BR262 - Wideband Voice Capture and Noise

BelaSigna R262
Wideband Voice Capture
and Noise Reduction
Solution
Introduction
Key Features and Benefits
• Drop−in Solution that Works without Special Tuning
• Consistently Captures Voice Regardless of Acoustic Environment or
•
•
•
•
•
•
the Orientation of the Handheld Device While in Use
360° Voice Pick−up Adjustable From 5 cm to 5 m
No Constraints on Industrial Design or Microphone Model
Simultaneous Dual−configurable Outputs
De−reverberation
Low Power Consumption (17 mA active and 40 mA stand−by)
Miniature Size Allows Easy Integration into Existing Industrial
Designs
•
•
•
•
•
Mobile Phones
Notebook and Tablet Computers
Two−Way Radios and PTT Devices
VoIP Applications
Any Device that would Benefit from Improved Voice Pick−up
© Semiconductor Components Industries, LLC, 2012
November, 2012 − Rev. 2
WLCSP−26
W SUFFIX
CASE 567CY
WLCSP−30
W SUFFIX
CASE 567CT
MARKING DIAGRAMS
1
1
BR262
W30
ALYW
BR262
W30
W26
A
L
YW
BR262
W26
ALYW
= BelaSigna R262
= 30−ball version
= 26−ball version
= Assembly Location
= Wafer Lot
= Date Code Year & Week
= Pb−Free Package
= A1 Corner Indicator
ORIENTATION
ÈÈ
ÈÈ
1
Typical Applications
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BR262
W30
ALYW
BelaSigna® R262 is a complete system−on−chip (SoC) solution that
provides wideband advanced noise reduction in voice capture
applications such as mobile phones, VoIP applications including
webcams and tablet computers, two−way radios and other applications
that can benefit from improved voice clarity.
Featuring a novel approach to removing mechanical, stationary and
non−stationary noise, the chip preserves voice naturalness for greater
voice clarity and speech intelligibility even when the talker is further
away or not optimally aligned with the microphones, providing
unmatched freedom of movement for end−users. Designed to be
compatible with a wide range of codecs, baseband chips and
microphones without the need for calibration, BelaSigna R262 is easy
to integrate, improving manufacturers’ time to market.
Additional features include the ability to provide two
simultaneously processed outputs and to configure them depending on
the needs of a manufacturer’s device. The chip includes a highly
optimized DSP−based application controller with industry−leading
energy efficiency and is packaged in a highly compact 5.3 mm2
WLCSPs to fit into even the most sized−constrained architectures
while allowing the use of common industry printed circuit board
design technologies.
1
(Top View)
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 22 of this data sheet.
Publication Order Number:
BR262/D
BelaSigna R262
Table 1. ABSOLUTE MAXIMUM RATINGS
Parameter
Min
Max
Unit
−0.3
4.0
V
VSSD − 0.3 V
VDDO + 0.3 V
V
Operating temperature range
−40
85
°C
Storage temperature range
−40
85
°C
Power Supply (Applies on VBAT, VBATRCVR and VDDO for “Max” and for
VSSA, VSSRCVR and VSSD for “Min”) (Note 1)
Digital input pin voltage
Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the
Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect
device reliability.
1. Time limit at maximum voltage must be less than 100 ms.
NOTE: Refer to ELECTRICAL CHARACTERISTICS and APPLICATION INFORMATION for Safe Operating Area.
This device series incorporates ESD protection and is tested by the following methods:
− ESD Human Body Model (HBM) tested per AEC−Q100−002 (EIA/JESD22−A114)
− ESD Machine Model (MM) tested per AEC−Q100−003 (EIA/JESD22−A115)
This device series incorporates latch−up immunity and is tested in accordance with JESD78.
Electrical Performance Specifications
Table 2. ELECTRICAL CHARACTERISTICS (The typical parameters in Table 2 were measured at 20°C with a clean
3.3 V supply voltage (unless noted differently). Parameters marked as screened are tested on each chip. Other parameters are qualified
for all process corners but not tested on every part.)
Parameter
Symbol
Test Conditions / Notes
Min
Typ
Max
Unit
1.65
3.3
3.63
V
10
ms
Screened
OVERALL
Supply voltage
VBAT
Maximum rise time
Between 0 V and 1.8 V
Average current consumption
Active mode, VBAT = 3.3 V,
EXT_CLK = 2.048 MHz
16.0
16.5
17.0
mA
Bypass mode, VBAT = 3.3 V,
EXT_CLK = 2.048 MHz
16.0
16.5
17.0
mA
Bypass mode, VBAT = 3.3 V,
Internal clock
2.7
2.8
2.9
mA
Sleep mode, VBAT = 3.3 V
39
40
Peak active current
VBAT = 3.63 V
mA
19
21
mA
1.00
1.05
V
5
20
mV/mA
2
mA
5
mV/V
2.1
V
VREG (1 mF External Capacitor)
Output voltage
VREG
Without load, or with microphone attached (0 to 200 mA)
PSRR
@ 1 kHz
Load regulation
@ 2 mA
0.95
40
dB
Load current
Line regulation
l
−1
VDDA (1 mF External Capacitor on VDDA + 100 nF External Capacitor on CAP0/CAP1)
Output voltage
VDDA
Unloaded with VREG = 1 V
1.8
PSRR
@ 1 kHz
45
Load regulation
@ 1 mA
2.0
l
dB
140
mV/mA
Load current
100
1
mA
Line regulation
2
mV/V
1.98
V
VDDD (1 mF External Capacitor)
Output voltage
VDDD
1.62
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2
1.70
l
BelaSigna R262
Table 2. ELECTRICAL CHARACTERISTICS (continued) (The typical parameters in Table 2 were measured at 20°C with a clean
3.3 V supply voltage (unless noted differently). Parameters marked as screened are tested on each chip. Other parameters are qualified
for all process corners but not tested on every part.)
Parameter
Symbol
Test Conditions / Notes
Min
Typ
Max
Unit
Screened
VMIC = VREG
0.95
1.00
1.05
V
l
VMIC = VDDA
1.8
2.0
2.1
V
l
VMIC = VREG
25
40
mV/mA
VMIC = VDDA
100
150
mV/mA
VMIC
Output voltage
Load Regulation
POWER ON RESET
POR Threshold
Boot Time
POR Release
(VBAT going up)
1.52
1.60
1.71
V
l
POR Activation
(VBAT going down)
1.52
1.60
1.65
V
l
NRST to DMIC active using
LSAD boot method
16.3
ms
NRST to DMIC active using
SPI EEPROM boot method
(Default custom application)
90
ms
NRST to DMIC active using
I2C EEPROM boot method
(Default custom application)
135
ms
21.333
kHz
INPUT STAGE
Sampling frequency
Fs
Defined by ROM−based
application. (Note 2)
Analog input voltage
Vin
No preamp gain on AI1
and AI3
0
2
Vpp
Vin
24 dB preamp gain by default
on MIC0 and MIC2
0
125
mVpp
1 kHz
−2
2
dB
Preamplifier gain tolerance
Input impedance
Rin
0 dB preamplifier gain
All other gain settings
Input offset voltage
250
510
585
kW
0 dB preamp gain
7
mV
All other gains
3
mV
−84
−60
dB
20
30
kHz
Channel cross coupling
Any 2 channels
Analog Filter cut−off frequency
LPF enabled (default)
10
LPF disabled
50
Analog Filter passband flatness
−1
Analog filter stopband
attenuation
60
Digital Filter cut−off frequency
kHz
1
dB
dB
Fs/2
Digital Filter cut−off stopband
attenuation
Total Harmonic Distortion +
Noise (Peak value)
kW
80
kHz
dB
THDN
24 dB preamplifier gain
VBAT = 3.3 V
−67
−70
dB
Dynamic Range
DR
24 dB preamplifier gain
VBAT = 3.3 V
81
82.5
dB
Equivalent Input Noise
EIN
24 dB preamplifier gain
VBAT = 3.3 V
3.7
mV
2. Processed bandwidth limited to 8 kHz.
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3
l
BelaSigna R262
Table 2. ELECTRICAL CHARACTERISTICS (The typical parameters in Table 2 were measured at 20°C with a clean
3.3 V supply voltage (unless noted differently). Parameters marked as screened are tested on each chip. Other parameters are qualified
for all process corners but not tested on every part.)
Parameter
Symbol
Test Conditions / Notes
Min
Typ
Max
Unit
Screened
DIGITAL MICROPHONE OUTPUT
DMIC input clock frequency
With preset 0 selected on
CLOCK_SEL (Note 3)
2.048
MHz
With preset 3 selected on
CLOCK_SEL (Note 3)
2.4
MHz
With preset 4 selected on
CLOCK_SEL (Note 3)
2.8
MHz
With preset 5 selected on
CLOCK_SEL (Note 3)
3.072
MHz
Clock duty cycle
Any clock configuration
Input clock jitter
Maximum allowed jitter on the
DMIC_CLK
Clock to output transition time
DMIC_OUT
40
10
50
20
60
%
10
ns
50
ns
ANALOG OUTPUT STAGE
Signal Range
Vout
One single ended DAC used
0
2
Vpp
Two DACs used as one
differential output
0
4
Vpp
−2
2
dB
@ 12 dB output attenuation
19
kW
@ 0 dB output attenuation
3
kW
−50
dB
13.0
13.5
kHz
25
26
kHz
−1
1
dB
Attenuator gain tolerance
Output impedance
Rout
Channel cross coupling
@ 1 kHz
Analog Filter cut−off frequency
LPF Enabled (default)
LPF Disabled
Analog Filter passband flatness
Analog filter stopband
attenuation
> 60 kHz
90
Digital Filter cut−off frequency
Total Harmonic Distortion +
Noise (Peak value)
Dynamic Range
dB
Fs/2
Digital Filter cut−off stopband
attenuation
l
kHz
80
dB
THDN
63
65
dB
l
DR
78
80
dB
l
l
Noise Floor
70
100
mV
3.3
3.63
V
DIRECT DIGITAL OUTPUT (available only through custom configuration)
Supply voltage
VBATRCVR
Signal Range
Vout
Output Impedance
Rout
1.8
Differential Output @ 1 kHz
0
2*VBAT
RCVR
Vpp
Single ended Output @ 1 kHz
0
VBAT
RCVR
Vpp
10
W
25
mA
Load between
1 mA and 30 mA @ 0°C
2.5
Maximum Current
Total Harmonic Distortion +
Noise (Peak value)
THDN
64
70
dB
l
3. Many other clock frequencies are available through custom configuration of the internal PLL and clocking subsystem. See later in this
document and in the BelaSigna R262 Communications and Configuration Guide for more information on custom mode usage.
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BelaSigna R262
Table 2. ELECTRICAL CHARACTERISTICS (continued) (The typical parameters in Table 2 were measured at 20°C with a clean
3.3 V supply voltage (unless noted differently). Parameters marked as screened are tested on each chip. Other parameters are qualified
for all process corners but not tested on every part.)
Parameter
Symbol
Test Conditions / Notes
Min
Typ
80
86
Max
Unit
Screened
dB
l
75
mV
l
2*VREG
V
4.8
kHz
DIRECT DIGITAL OUTPUT (available only through custom configuration)
Dynamic Range
DR
Noise Floor
50
LOW−SPEED A/D
Input voltage
Vin
Sampling frequency
Input impedance
0
For each LSAD channel
Rin
1.6
MCLK/28
1
MW
Offset error
Input at VREG
−10
10
LSB
Gain error
Input to VSSA or 2*VREG
−10
10
LSB
INL
INL
−4
4
LSB
DNL
DNL
−2
2
LSB
Voltage level for Low input
VIL
−0.3
0.4
V
Voltage level for High input
VIH
1.30
1.98
V
DIGITAL PADS (VDDO = 1.8 V)
Pull−up resistance
63
114
162
kW
Pull−down resistance
87
153
205
kW
2
3
5
ns
Rise and Fall Time
20 pF load
DIGITAL PADS (VDDO = 3.3 V)
Voltage level for Low input
VIL
−0.3
0.8
V
l
Voltage level for High input
VIH
1.8
3.6
V
l
74
kW
l
l
Pull−up resistance
34
Pull−down resistance
Rise and Fall Time
20 pF load
46
29
56
86
kW
1.0
1.5
2.0
ns
DIGITAL PADS (Common parameters)
12
Drive Strength
ESD Immunity
HBM
Human Body Model
MM
Latch−up Immunity
mA
2
kV
Machine Model
200
V
25°C, V < GNDO, V > VDDO
150
mA
CLOCKING CIRCUITRY
External clock frequency
EXT_CLK
With preset 6 selected on
CLOCK_SEL (Note 3)
26
MHz
Internal clock frequency
INT_CLK
With preset 7 selected on
CLOCK_SEL (Note 3)
Bypass Mode
5.2
MHz
With preset 7 selected on
CLOCK_SEL (Note 3)
Active Mode
48.2
MHz
Reference clock duty cycle
External Input clock jitter
40
Maximum allowed jitter on
EXT_CLK
50
60
%
10
ns
400
kbps
I2C INTERFACE
Maximum speed
3. Many other clock frequencies are available through custom configuration of the internal PLL and clocking subsystem. See later in this
document and in the BelaSigna R262 Communications and Configuration Guide for more information on custom mode usage.
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BelaSigna R262
Table 3. PIN CONNECTIONS
Pin Index
Pin Name
G1
MIC0
E5*
AI1/LOUT1
E1
MIC2
E3
AI3/VMIC/LOUT0
D6*
Description
A/D/P
I/O
Active
Pull
First microphone input
A
I
Direct audio input / line−out preamp 1
A
I/O
Second microphone input
A
I
Direct audio input / microphone bias /
line−out preamp 0
A
I/O
A_OUT0
Audio output 0
A
O
E7
A_OUT1
Audio output 1
A
O
G7
CAP0
Charge pump capacitor connection
A
I/O
F8
CAP1
Charge pump capacitor connection
A
I/O
A1
DEBUG_RX
RS232 debug port serial input
D
I
L
U
B2
DEBUG_TX
RS232 debug port serial output
D
O
L
F2
RESERVED
Reserved
A3
EXT_CLK
D
I
A7
SPI_CLK/CLOCK_SEL
A9
SPI_CS/BOOT_SEL
SPI clock / Clock selection
D/A
O/I
SPI chip select / Booting method selection
D/A
O/I
B8
SPI_SERO/CHAN_SEL
SPI serial output / Channel selection
D/A
O/I
C9
SPI_SERI/ALPHA_SEL
SPI serial input / Mixing ratio selection
D/A
I/I
C7
DMIC_OUT
Digital microphone output
D
O
C5*
SWAP_CHAN
Channel swap control
D
I
External clock input
U
L/−
U/−
U
C3
I2C_SDA
I2C
D
IO
L
U
C1
I2C_SCL
I2C clock
D
IO
L
U
D4*
NRESET
Reset
D
I
L
U
F6
VBAT
Power supply
P
I
G9
VBATRCVR
Output driver power supply
P
I
G5
VDDA
Analog supply voltage
P
O
B6
VDDD
Digital power supply
P
O
B4
VDDO
Digital I/O power supply
P
I
G3
VREG
Analog supply voltage
P
O
F4
VSSA
Analog ground
P
I
A5
VSSD
Digital ground
P
I
E9
VSSRCVR
Output driver ground
P
I
data
* Pins C5, D4, D6 and E5 are not available on the WLCSP26 package.
All pins are available on the WLCSP30 package.
A: Analog pin
D: Digital pin
P: Power pin
I: Input
O: Output
IO: Bi−directional
I/O & O/IL: Input or Output depending on the function being used
L: Active Low
H: Active High
U: Pulled up internally
D: Pulled down internally
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BelaSigna R262
Application Diagrams
1.8V − 3.3V
1uF
VSSD
VSSD
VDDO
VSSA
VDDA
VREG
VBAT
VSSA
VBATRCVR
1uF
VSSD
VMIC
1uF
1uF
1uF
VDDD
+
−
2.2 kW
A_OUT0
10nF
MIC2
Microphone 2
Advanced
Speech and
Noise
Management
A/D
MUX
MIC0
Microphone 0
A/D
A_OUT1
D/A
DMIC
CLOCK_SEL
VREG
2.2uF
D/A
BOOT_SEL
Laptop Codec
or
Baseband Chip
DMIC_OUT
EXT_CLK
VREG
AGND
CHAN_SEL
BelaSigna R262
VREG
ALPHA_SEL
CAP0
CAP1
AGND
VSSD
VSSRCVR
VREG
VSSA
AGND
AGND
100nF
Figure 1. Typical Application Diagram for 30−ball WLCSP Package Option
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BelaSigna R262
Applications Information
Recommended Circuit Design Guidelines
Recommended Ground Design Strategy
BelaSigna R262 is designed to allow both digital and
analog processing in a single system. Due to the mixed−
signal nature of this system, careful design consideration of
the printed circuit board (PCB) layout is critical to maintain
the high audio fidelity of BelaSigna R262. To avoid
coupling noise into the audio signal path, keep the digital
traces away from the analog traces. To avoid electrical
feedback coupling, isolate the input traces from the output
traces.
The ground plane should be partitioned into two parts: the
analog ground plane (VSSA) and the digital ground plane
(VSSD). These two planes should be connected together at
a single point, known as the star point. The star point should
be located close to the negative terminal of the power source,
as illustrated in Figure 2.
All ground returns should be routed separately back to the
appropriate ground plane, i.e. do not share a ground return.
Ensure that different ground and/or power planes do not
overlap each other if located on different layers in the board.
1.8V − 3.3V
VBATRCVR
VBAT
+
BelaSigna R262
Battery
VDDO
VDDA
VREG
Start Ground
Point
VSSA
VDDD
VSSRCVR
VSSD
Digital Ground Plane
Analog Ground Plane
(place under analog side of BR262)
VSSRCVR Ground
(route separately to star ground point)
Figure 2. Schematic of Ground Scheme
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(keep away from
analog ground plane,
place under digital side of BR262)
BelaSigna R262
G1 = MIC0
E1 = MIC2
Analog Ground Plane
1
2
3
4
5
6
7
8
9
F2 = RESERVED
G3 = VREG
E3 = VMIC
G
F4 = VSSA
D4 = NRESET
F
G5 = VDDA
E5 = AI1
E
G1
G3
F2
E1
F4
E3
A1 = DEBUG_RX
B2 = DEBUG_TX
G7
F6
E5
D4
D
C1 = I2C_SCL
C3 = I2C_SDA
G5
G9
E9
C5 = SWAP_CHAN
G9 = VBATRCVR
E9 = VSSRCVR
D6
B6 = VDDD
C7 = DMIC_OUT
C
C1
C3
C5
C7
C9
A7 = SPI_CLK
A7 = CLOCK_SEL
B2
B
B4
B6
B8
B8 = SPI_SERO
B8 = CHAN_SEL
A3 = EXT_CLK
B4 = VDDO
A5 = VSSD
D6 = A_OUT0
E7 = A_OUT1
G7 = CAP0
F8 = CAP1
F8
E7
F6 = VBAT
A
A1
A3
A5
A7
A9
Digital Ground Plane
C9 = SPI_SERI
C9 = ALPHA_SEL
A9 = SPI_CS
A9 = BOOT_SEL
Figure 3. Proposed Ground Plane Positioning (soldering footprint view)
Internal Power Supplies
The VSSD plane is used as the ground return for digital
circuits and should be placed under digital circuits. The
VSSA plane should be kept as noise−free as possible. It is
used as the ground return for analog circuits and it should
surround analog components and pins. It should not be
connected to or placed under any noisy circuits such as RF
chips, switching supplies or digital pads of BelaSigna R262
itself. Analog ground returns associated with the audio
output stage should connect back to the star point on separate
individual traces.
For details on which signals require special design
consideration, see Table 4 and Table 5.
In some designs, space constraints may make separate
ground planes impractical. In this case a star configuration
strategy should be used. Each analog ground return should
connect to the star point with separate traces.
Power management circuitry in BelaSigna R262
generates separate digital (VDDD) and analog (VREG,
VDDA) regulated supplies. Each supply requires an
external decoupling capacitor, even if the supply is not used
externally. Decoupling capacitors should be placed as close
as possible to the power pads.
The digital I/O levels are defined by a separate power
supply pin on BelaSigna R262 (VDDO). This pin must be
externally connected by the application PCB, usually to
VBAT.
Further details on these critical signals are provided in
Table 4. Non−critical signals are outlined in Table 5. More
information on the power supply architecture can be found
in the Power Supply Unit section.
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BelaSigna R262
Table 4. CRITICAL SIGNALS
Pin Name
Description
Connection Guidelines
VBAT
Power supply
Place 1 mF (min) decoupling capacitor close to pin
Connect negative terminal of capacitor to digital ground plane
VREG, VDDA
Internal regulator for analog
blocks
Place separate 1 mF decoupling capacitors close to each pin
Connect negative capacitor terminal to analog ground plane
Keep away from digital traces and output traces
VREG and VDDA may be used to generate microphone bias
VSSA
Analog ground return
VDDD
Internal regulator for digital core
VSSD
Digital ground return
VDDO
Digital I/O power
MIC0, MIC2,
AI1/LOUT1,
AI3/VMIC/LOUT0
Audio inputs / Microphone bias
A_OUT0, A_OUT1
Audio outputs
VSSRCVR
Output stage ground return
Connect to star ground point
Keep away from all analog audio inputs
EXT_CLK
External clock input
Minimize trace length
Keep away from analog signals
If possible, surround with digital ground
DMIC_OUT
Digital Microphone Output
Minimize trace length
Keep away from analog signals
If possible, surround with digital ground
Connect to analog ground plane
Place 1 mF decoupling capacitor close to pin
Connect negative terminal of capacitor to digital ground plane
Connect to digital ground plane
Place 1 mF decoupling capacitor close to pin
Connect negative terminal of capacitor to digital ground plane
Connect to VBAT, unless the pad ring must use different voltage levels
Keep traces as short as possible
Keep away from all digital traces and audio outputs
Avoid routing in parallel with other traces
Never connect AI3/VMIC/LOUT0 to ground
Keep away from audio inputs
Differential traces should be of approximately the same length
Ideally, route lines parallel to each other
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BelaSigna R262
Table 5. NON−CRITICAL SIGNALS
Pin Name
Description
Connection Guidelines
CAP0, CAP1
Internal charge pump −
capacitor connection
Place 100 nF capacitor very close to pins
I2C_SDA, I2C_SCL
I2C port
Keep as short as possible. Place pull−up resistors (10 kW) to VDDO
SWAP_CHAN
Control GPIO
Not critical when used as GPIO
CLOCK_SEL,
BOOT_SEL,
CHAN_SEL and
ALPHA_SEL
Low−speed A/D converters
(Multiplexed with SPI port)
Not critical when used as LSAD
Place resistive divider for hardware configuration of BelaSigna R262
SPI_CLK, SPI_CS,
SPI_SERO,
SPI_SERI
Serial peripheral interface port
(Multiplexed with LSAD and
GPIOs)
Keep away from analog input lines when used as SPI signals
NRESET
Reset
Not critical
Leave unconnected if unused
DEBUG_RX,
DEBUG_TX
Debug Port
Not critical
If possible, connect to test points, otherwise connect DEBUG_RX to VDDO
and leave DEBUG_TX floating
RESERVED
Reserved pin
Leave unconnected or connect to VSSA if PCB routing constraints force it
VBATRCVR
Output driver power supply
If the output driver is being used:
− Place a separate 4.7 mF (min. 2.2 mF) decoupling capacitor close to pin
− Connect positive terminal of capacitor to VBAT & VBATRCVR
− Connect negative terminal of capacitor to VSSRCVR
If the analog outputs or the DMIC output are being used:
− Separate decoupling capacitor on VBATRCVR is not required
− Connect VBATRCVR to VDDA (which has its own decoupling capacitor)
Audio Inputs
because of PCB routing constraints, the power supplies
VREG (1.0 V) or VDDA (2.0 V) can alternatively be used.
Keep audio input traces strictly away from output traces.
Audio outputs must be kept away from microphone inputs
to avoid cross−coupling.
The audio input traces should be as short as possible. The
input impedance of each audio input pad (e.g., MIC0, AI1,
MIC2, AI3) is high (approximately 500 kW with
preamplifiers enabled); therefore a 10 nF capacitor is
sufficient to decouple the DC bias. This capacitor and the
internal resistance form a first−order analog high pass filter
whose cut−off frequency can be calculated by
f3dB (Hz) = 1/(R x C x 2π), which results in ~30 Hz for a
10 nF capacitor. This 10 nF capacitor value applies when the
preamplifier is being used, in other words, when a non−unity
gain is applied to the signals; for MIC0 and MIC2, the
preamplifier is enabled by the ROM−based application.
When the preamplifier is bypassed, the impedance is
reduced; hence, the cut−off frequency of the resulting
high−pass filter could be too high. In such a case, the use of
a 30−40 nF serial capacitor is recommended. In cases where
line−level analog inputs without DC bias are used, the
capacitor may be omitted for transparent bass response.
ON Semiconductor recommends the use of NPO/COG
dielectric for SMT capacitors, as they have demonstrated
better performance compared to other capacitors with X7R
dielectric.
Audio Outputs
The audio output traces should be as short as possible. The
trace length of the two signals should be approximately the
same to provide matched impedances.
Recommendation for Unused Pins
Table 6 shows the connection details for each pin when
they are not used.
Table 6. UNUSED PIN RECOMMENDATIONS
Signal Name
Microphone Power Supply
BelaSigna R262 provides a microphone power supply
(VMIC) and ground (VSSA). In case VMIC cannot be used
A_OUT0
Do not connect
A_OUT1
Do not connect
AI3/VMIC/LOUT0
Do not connect
AI1/LOUT1
Connect to VSSA
DMIC_OUT
Do not connect
SWAP_CHAN
Do not connect
NRESET
Do not connect
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Connection Guidelines
BelaSigna R262
Architecture Detailed Information
The architecture of BelaSigna R262 is shown in Figure 4.
Interpolation
Preamps Decimation
MUX
A/D
A/D
Advanced
Speech and
Noise
Management
DSP−Based
Application Controller
SPI
Debug
Port
LSAD
Custom
Mode
Handler
Algorithm
Control
Boot
Selection
Sleep Mode
Control
D/A
D/A
DMIC
GPIO
PCM/I2S
UART
I2C
Command
Handler
H/W Config
Selection
PLL and
Clock
Detection
Mode
Switching
System
Monitoring
Power Mgt
I2C
BelaSigna R262
Figure 4. BelaSigna R262 Architecture: A Complete Audio Processing System
Algorithm Performance and Configuration
For details on the configuration of the algorithm, refer to
the BelaSigna R262 Communications and Configuration
Guide.
A detailed description of the functional blocks of the
algorithm contained in BelaSigna R262, as well as
performance metrics can be found in AND9109/D − Getting
Started with BelaSigna R262.
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BelaSigna R262
Microphone Placement & Selection
• The dynamic range of BelaSigna R262 on its analog
The flexibility of the BelaSigna R262 noise reduction
algorithm doesn’t restrict microphone placements, but the
default algorithm will operate optimally with
omnidirectional microphones placed in the following
configuration:
• The two microphones are facing the user’s mouth
• The microphone centers are located within 10 to 25 mm
from each other
As mentioned, other configurations that differ from the
above guidelines are supported. For example, a 15 cm
distance between the two microphones will not degrade the
performance as long as the microphones are both facing the
user’s mouth. Alternatively, a configuration with one
microphone at the front and one microphone at the back will
not degrade the performance either, as long as the distance
between the microphones is no more than 2 cm.
BelaSigna R262 does not require any acoustic
microphone calibration procedure.
When selecting microphones to be used with
BelaSigna R262, the following guidelines should be used:
• Two omni−directional microphones with similar
characteristics should be used
• The microphone sensitivity should be approximately
−42 dB (where 0 dB = 1 V/Pa, at 1 kHz)
• The microphones are two−terminal microphones
• The microphone power supply is either 1 V
(recommended), or 2 V if it is to be provided by
BelaSigna R262
•
•
input channels is 2.0 V peak−to−peak, after
amplification by the default gain value of 24 dB using
BelaSigna R262’s input preamplifiers
When higher sensitivity microphones are used, the
preamp gain should be adjusted to match the 2.0 Vpp
input voltage swing on BelaSigna R262, but this will
require special configuration of the ROM application,
as described later. As an example, using microphones
with a −22 dB sensitivity typically requires that the
preamplifier gains be changed down to 12 dB.
When MEMS microphone are to be used, a general
increase of the algorithm performance can be expected
due to the improved self noise of these microphones,
compared to conventional electret microphones. For
applications requiring microphone configurations
differing significantly from the above recommendations,
contact your local ON Semiconductor support
representative.
Operating Modes
The default application stored in the ROM of
BelaSigna R262 has four Operating Modes. The Operating
Modes are summarized in Table 7.
Table 7. OPERATING MODES SUMMARY
Operating
Mode
Switching
Description
Active
Active mode can be entered at boot time,
depending on the BOOT_SEL configuration and
when exiting Sleep mode. Active mode can also
be entered via an I2C command from another
mode.
In Active mode, the noise reduction algorithm is executed. While
in Active mode, BelaSigna R262 collects statistics on the input
signals that can be retrieved via I2C. These signal statistics can
be used for level calibration and other debugging. For more
information using Active mode for calibration and debugging see
the BelaSigna R262 Communications and Configuration Guide.
Bypass
Bypass mode can be entered at boot time,
depending on the BOOT_SEL configuration. It
can also be entered via an I2C command from
another mode.
In Bypass mode, no signal processing is done on the audio
inputs. The inputs are passed directly to the audio outputs. While
in Bypass mode, BelaSigna R262 collects statistics on the input
signals that can be retrieved via I2C. These signal statistics can
be used for level calibration and other debugging. For more
information using Bypass mode for calibration and debugging see
the BelaSigna R262 Communications and Configuration Guide.
Sleep mode can be entered via I2C commands.
When Sleep mode is entered via I2C, the chip will
exit Sleep mode only based on activity on the
I2C_SCL pin. Sleep mode will be automatically
entered if BelaSigna R262 detects that a required
external clock is no longer present. For more
information, see the Sleep Control section below.
In Sleep mode no signal processing is done. All analog blocks of
the chip are disabled and the digital core continues to run off an
internal low−speed oscillator, thereby allowing the external clock
to be disabled when the chip is asleep. This is BelaSigna R262’s
lowest power operating mode.
Stand−By mode is an intermediate mode that is
only used when exiting sleep mode by an I2C
command.
When I2C is used to exit Sleep mode, the application will
transition to Stand−By mode, and will wait until the master I2C
device issues a Switch_Mode command to enter another
processing mode like Active or Bypass. If no such command is
issued, BelaSigna R262 will return to Sleep mode and wait for a
valid wake−up sequence.
Sleep
Stand−By
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BelaSigna R262
Boot Control, Hardware Configuration and
Digital Control
At power−on−reset, BelaSigna R262 will normally
execute the application stored in ROM. During the boot
process, BelaSigna R262 will read voltage levels on four
different pins, which will determine the algorithm and
hardware configuration that will be executed. All the
configuration options are described later in this section; the
four pins are CLOCK_SEL, BOOT_SEL, CHAN_SEL and
ALPHA_SEL.
The BOOT_SEL pin controls the booting methods of
BelaSigna R262. The signal on this pin is sampled by
BelaSigna R262 during its booting process using a
low−speed A/D converter (LSAD). Based on the actual
voltage that the chip will read on this pin, it will
automatically select a particular booting configuration, as
described in Table 8.
Table 8. BOOT SELECTION OPTIONS (Note 4)
Preset
Voltage Level
Boot Method
Description
0−2
0.65 − 1.00 V
External Boot Mode
In this mode, BelaSigna R262 will not run the ROM based application. It will start looking for an SPI EEPROM to bootload a custom
application from. If unsuccessful, it will look for an I2C EEPROM to
bootload a custom application; and lastly, if neither of the two previous operations to find an EEPROM are successful, it will enter a
wait loop, allowing a master I2C device to start downloading a custom application (e.g. a baseband controller).
3
0.50 − 0.63 V
Active Mode
Talking distance selectable from
Near− to Far−Talk
(50 cm to 500 cm)
The noise reduction algorithm is running and can be configured for
talking distances between 50 cm (Near−Talk) and 5 m (Far−Talk)
4
0.36 − 0.49 V
Active Mode
Talking distance selectable from
Close− to Far−Talk
(5 cm to 500 cm)
The noise reduction algorithm is running and can be configured for
talking distances between 5 cm (Close−Talk) and 5 m (Far−Talk)
5
0.22 − 0.35 V
Active Mode
Talking distance selectable from
Close− to Near−Talk
(5 cm to 100 cm)
The noise reduction algorithm is running and can be configured for
talking distances between 5 cm (Close−Talk) and 1 m (Near−Talk)
6
0.08 − 0.21 V
Bypass Diagnostic Mode
1 kHz sine wave play−out
BelaSigna R262 outputs a pure tone on the two output channels.
This sine wave has a frequency of 1 kHz and an output level of
12 dB below full scale.
7
0 − 0.07 V
Bypass Diagnostic Mode
Full stereo passthrough
BelaSigna R262 simply copies the input signals to the outputs.
4. For more details on the various operating modes of BelaSigna R262, please consult the BelaSigna R262 Communications and Configuration
Guide.
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BelaSigna R262
Clocking, Channels & Algorithm Configuration
using a low−speed A/D converters (LSAD). Based on the
actual voltage that the chip reads on these pins, it will
automatically select a particular clock, output stage,
channels and algorithm configuration, as described in
Tables 9, 10 and 11.
As mentioned in the Boot Control section,
BelaSigna R262 is controlled by hardware configuration.
Just like the BOOT_SEL signal discussed earlier, the
CLOCK_SEL, CHAN_SEL and ALPHA_SEL pins are also
sampled by BelaSigna R262 during its booting process
Table 9. CLOCK CONFIGURATION OPTIONS
Preset
Voltage Level
Clock Frequency
Description
0−2
0.65 − 1.00 V
2.048 MHz
A 2.048 MHz external clock is expected to be present on the EXT_CLK pin of
BelaSigna R262
3
0.50 − 0.63 V
2.4 MHz
A 2.4 MHz external clock is expected to be present on the EXT_CLK pin of
BelaSigna R262
4
0.36 − 0.49 V
2.8 MHz
A 2.8 MHz external clock is expected to be present on the EXT_CLK pin of
BelaSigna R262
5
0.22 − 0.35 V
3.072 MHz
6
0.08 − 0.21 V
26 MHz
7
0 − 0.07 V
Internal Oscillator
A 3.072 MHz external clock is expected to be present on the EXT_CLK pin of
BelaSigna R262
A 26 MHz external clock is expected to be present on the EXT_CLK pin of
BelaSigna R262
BelaSigna R262 runs off its internal system clock. No clock signal must be
present on the EXT_CLK pin. In this mode the sampling frequency can fluctuate slightly from one device to another; see the electrical characteristics for
additional details. The performance of the algorithm itself is fully guaranteed.
Table 10. CHANNEL CONFIGURATION OPTIONS
Preset
Voltage Level
NR Outputs
Channel 0
Channel 1
Output Stage Configuration
0−2
0.65 − 1.00 V
Single
Start of Range
(as per BOOT_SEL)
N/A
Mono,
Differential
3
0.50 − 0.63 V
Dual
Start of Range
(as per BOOT_SEL)
Mixed Output
(as per BOOT_SEL &
ALPHA_SEL)
Stereo,
Single Ended
4
0.36 − 0.49 V
Dual
Mixed Output
(as per BOOT_SEL &
ALPHA_SEL)
End of Range
(as per BOOT_SEL)
Stereo,
Single Ended
5
0.22 − 0.35 V
Single
Mixed Output
(as per BOOT_SEL &
ALPHA_SEL)
N/A
Mono,
Differential
6
0.08 − 0.21 V
Single
Mixed Output
(as per BOOT_SEL &
ALPHA_SEL)
Algorithm Disabled
Stereo,
Single Ended
7
0 − 0.07 V
Single
Algorithm Disabled
Mixed Output
(as per BOOT_SEL &
ALPHA_SEL)
Stereo,
Single Ended
Table 11. MIXER CONFIGURATION OPTIONS
Preset
Voltage Level
Mixing Ratio
0−2
0.65 − 1.00 V
0% (Start of Range)
3
0.50 − 0.63 V
20% (Between Start and End of Range)
4
0.36 − 0.49 V
40% (Between Start and End of Range)
5
0.22 − 0.35 V
60% (Between Start and End of Range)
6
0.08 − 0.21 V
80% (Between Start and End of Range)
7
0 − 0.07 V
100% (End of Range)
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BelaSigna R262
The use of a resistive divider as shown in Figure 5 allows
the application to select the appropriate combination of
clock, output stage and algorithm mode. The LSAD is using
a voltage range between 0 and 1 V. The actual voltage levels
that need to be guaranteed by the application circuitry are
also mentioned in Figure 5. The figure proposes actual
resistor values to reach the eight different presets.
VREG
Preset
R1
R2
Voltage Range
0−2
10 kW
−
0.65 − 1.00 V
3
75 kW
100 kW
0.50 − 0.63 V
4
100 kW
75 kW
0.36 − 0.49 V
5
100 kW
39 kW
0.22 − 0.35 V
6
100 kW
16 kW
0.08 − 0.21 V
7
−
10 kW
0 − 0.07 V
The configuration is only read by the chip at boot time.
Consequently, if the voltage on any of the four LSAD inputs
changes during operation, it will only have an impact at the
next power cycle.
R1
LSAD Pin
R2
Channel Swapping
BelaSigna R262 has provisions to swap the two output
channels by using an external GPIO pin (SWAP_CHAN).
The two output channels of BelaSigna R262 can be swapped
whenever the digital signal on this pin transitions to low and
stays low for at least 200 ms, as shown in Figure 6. The actual
channel swapping can occur at any time during the 200 ms
low period of the signal. This control mechanism has built-in
button de-bouncing and will work with either a digital signal
driven high or low by a host controller, or with a control
signal provided by a mechanical button or switch.
Figure 5. Resistive Dividers for LSAD Preset
Selection
200 ms (min)
200 ms (min)
SWAP_CHAN
Channel State
Normal
Swapped
Normal
Figure 6. SWAP_CHAN Timing Diagram
Sleep Control
2. Send the Get_Status command in a while−type loop,
until a response from BelaSigna R262 is sent, and
that confirms that the application is in Standby Mode.
3. Send a Switch_Mode command to enter the desired
mode (Active or Bypass).
When the NOP command is sent and the chip wakes up,
the master has about one second to complete the above
procedure before the chip goes back to Sleep mode. This
mechanism was put in place to deal with I2C bus traffic that
would wake the chip up unintentionally (i.e. communications
between the master and another slave on the I2C bus).
The second mechanism for entering Sleep mode is
considered a fail safe mechanism to maintain a graceful
system shutdown in the event that the clock source suddenly
disappears. In this circumstance, the chip will enter sleep
mode to ensure proper shutdown. More information on this
can be found in the System Monitoring section.
As described in Table 7, there are two methods to enter and
exit from Sleep mode. Both of these methods are meant to
be used independently, i.e. methods of putting the system
into Sleep mode and waking it up from Sleep mode cannot
be mixed in the same system design.
The first method for Sleep mode control is via the I2C
interface. The Switch_Mode command can be used directly
to switch the system into and out of Sleep mode. If the
Switch_Mode command is used to put the chip into Sleep
mode, only another Switch_Mode command or a reset will
take the system out of Sleep mode. When waking up by I2C
commands, the following I2C operations have to be
performed by the master I2C to ensure proper wake−up:
1. Send a NOP command to wake up the I2C
interface. This command will not be interpreted by
BelaSigna R262, so the master will have to deal
with any I2C errors that result.
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BelaSigna R262
I2C Command Handler
Analog Blocks
The BelaSigna R262 ROM application contains an
I2C−based command and control interface, allowing many
aspects of the chip’s operation and hardware configuration
to be controlled via I2C. This I2C interface is the
recommended way to control the chip and to configure the
application at run−time. The default I2C address of
BelaSigna R262 is 0x61. The I2C interface protocol is fully
supported by the SignaKlara Device Utility (SKDU) and
other software tools provided by ON Semiconductor.
For more information on the I2C interface, please refer to
the I2C interface section of this document, as well as the
BelaSigna R262 Communications and Configuration
Guide.
Input Stages
The BelaSigna R262 analog audio input stage is shown in
Figure 7. The input stage is comprised of two individual
channels. There are four configurable aspects of each
channel – input multiplexing, preamplifier gain, filtering
and line out. The input multiplexing allows one input to be
selected from any of the four possible inputs and then routed
to the input of the preamplifier. Each preamplifier can be
configured for bypass or gain values of 12 to 30 dB in 3 dB
steps. The filters can be configured as well; the DC removal
high−pass filter can be bypassed, or set to a cut−off
frequency of 5 Hz, 10 Hz or 20 Hz (default). The low−pass
filter can be either enabled with a 20 kHz cut−off frequency
(default), or bypassed. The lineout selection allows the
preamplifier outputs to be routed back out via the auxiliary
audio input pins. Note that the AI1/LOUT1 pin is not
available on the 26−ball WLCSP package option.
Two analog−to−digital converters then convert the analog
signals into the digital domain. The ADCs are running at a
sampling rate of 21.3 kHz in Active mode and 16 kHz in
Bypass mode. The sampling rate can potentially be changed
using the I2C interface. Changing the sampling rate in
Active mode will cause the noise cancellation algorithm to
stop operating properly, so this should not be done; however,
the sampling rate in Bypass mode could be changed to other
values. Contact your local technical support for more
information.
Input signal amplitudes can also be adjusted in the digital
domain; digital gain for both converted signals can be
adjusted by using I2C commands.
The ROM−based application pre−configures all these
parameters in the input stage such that the algorithm
operates properly. These parameters can be changed using
the I2C interface, but careful design consideration should be
taken when doing so, as this could alter the performance of
the algorithm.
The AI3 pin is multiplexed with the microphone power
supply (VMIC). The default mode for the microphone bias
is to be used as a 2 V power supply. Consequently, any
application that plans to use the AI3 input pin or the LOUT0
functionality has to change the VMIC setting to high−
impedance mode, such as the pin can be properly used as an
analog input or a line−out.
Reset
BelaSigna R262 can be forced to execute a
power−on−reset by pulling the NRESET pin to ground for
at least 100 ns. NRESET is not available on the 26−ball
WLCSP package.
System Monitoring
The application software within BelaSigna R262 is
equipped with a few blocks that monitor system sanity. A
watchdog timer is used to ensure proper execution of the
signal processing application. It is always active and is
periodically acknowledged as a check that the application is
still running. Once the watchdog times out, a hardware
system reset will occur. System sanity is also monitored by
the clock detection mechanism; the chip will automatically
enter Sleep mode if it is in Active or Bypass mode and it
detects that the external clock source (the signal on
EXT_CLK) is stopped. In this case, the system will only exit
Sleep mode when it detects that the external clock source has
been restored or a reset occurs.
The power supply blocks of the system also monitor for
minimum supply voltages as part of the power supervision
strategy, as described in the Power Management section.
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BelaSigna R262
MIC0
AI1/LOUT1
M
U
X
MIC2
PA0
LPF0
ADC0
AI3/VMIC/LOUT0
Line
out
M
U
X
PA1
LPF1
ADC1
Line
out
Analog
Decimation
Filter
Input Stage
Channel 0
To IOP
Decimation
Filter
Input Stage
Channel 1
To IOP
Digital
Figure 7. Input Stage
Output Stage
The BelaSigna R262 output stage is shown in Figure 8.
The output stage processes two channels although,
depending on the configuration, one or both of the output
signals are available on the output pins. There are four
options for audio outputs from BelaSigna R262 – a digital
microphone (DMIC) interface, a low−impedance output
driver, a stereo single−ended analog output or a mono
differential analog output. All outputs are generated from a
sigma−delta modulator which produces a pulse density
modulated (PDM) output signal and then provides it to the
appropriate output system, based on the system
configuration.
At all times, the application will produce two output
channels. The content of each channel is determined by the
hardware configuration.
The amplitude of both output channels can be controlled
by I2C commands, independently from the actual output
stage configuration that was selected. A first parameter
controls gain in 6 dB steps. A second parameter is a variable
for fine gain adjustment. With these two parameters, a great
level of flexibility is achieved to match the output level
requirements of the target device, independently for each of
the two output channels. The application has initialized these
parameters for proper operation of the algorithm and correct
output so careful design consideration should be taken when
modifying these parameters.
DMIC_OUT
Combiner
From
Application
Channel 0
Interpolation
Filter
Delay,
inversion
and
muxing
Output
Modulator
Output Stage Channel 0
From
Application
Channel 1
Inversion
Interpolation
Filter
M
U
X
Output
Modulator
A_OUT0
Output
Driver 0
A_OUT1
DAC0
OA0
LPF
DAC1
OA1
LPF
Output Stage Channel 1
Digital
Analog
Figure 8. Output Stage
the incoming DMIC_CLK and the output data produced by
BelaSigna R262 on its DMIC_OUT pin. Various
DMIC_CLK frequencies are supported through hardware
configuration on the CLOCK_SEL pin, as discussed earlier.
Other frequencies can also be supported under certain
conditions; see the clocking section of this document for
The digital microphone interface provides the PDM
signals directly on a pin (DMIC_OUT), for interfacing with
the DMIC input of external systems. When using this
interface, the EXT_CLK input to BelaSigna R262 must be
given a DMIC_CLK signal and the system clocking must be
set up such that proper synchronization can happen between
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BelaSigna R262
stage channel 1. Also, both left and right can be configured
to be muted independently (driving a ‘0’ all the time).
Figure 9 shows the timing of the DMIC output data
relative to the incoming DMIC_CLK signal. See Table 2 for
electrical specifications of the timing parameters.
more information on the supported DMIC clock
frequencies.
The DMIC output can be configured to carry a mono or
stereo signal. In fact both left and right signals can be
configured to either contain output stage channel 0 or output
DMIC_CLK
Right
Data 0
DMIC_DATA
DMIC_
HOLD
DMIC_
HOLD
Left
Data 0
Right
Data 1
DMIC_
SETUP
Left
Data 1
Right
Data 2
DMIC_
SETUP
Figure 9. DMIC Timing Diagram
for single ended stereo or differential mono through the
same I2C commands as described for the analog outputs.
The output driver is disabled by the default application in
ROM.
For optimal audio performance it is important to note that
the VBATRCVR power supply must be connected
differently, depending on whether the output driver or the
analog outputs are being used:
• When using the analog outputs, VBATRCVR must be
connected to VDDA on the application PCB
• When using the output driver, VBATRCVR must be
connected to VBAT on the application PCB and must
be decoupled with an external capacitor
The application pre−configures the DMIC interface based
on the CHAN_SEL pin; when in a stereo configuration, it
always outputs a stereo signal with Channel 0 as the left
signal, and Channel 1 as the right signal. When in a mono
configuration, both the right and left signals will contain the
data processed on Channel 0, unless the SWAP_CHAN pin
was used to toggle the channels, in which case the DMIC
output would see the Channel 1 output on both left and right
signals.
When the DMIC interface is not required, the analog
outputs can be used for interfacing at line−level or other signal
levels, e.g. microphone levels for an external system such as
an analog baseband chipset which expects low−level
signals.
There are two configurable aspects of the analog output
stage – the selection of stereo (two single−ended outputs) or
mono (one differential output) and the output attenuation.
When a stereo single−ended option is selected, each channel
is filtered to generate an analog signal which is then scaled
by a configurable output attenuator (OA in Figure 9). In
mono differential mode, Channel 1 is replaced by an
inverted version of Channel 0 such that the two output pins
contain a differential signal for Channel 0. In this latter case,
both output attenuators are used, so it is mandatory to ensure
that they have the same attenuation settings. The default
attenuation value is 0 dB for both channels. This can be
configured using I2C commands.
The 26−ball WLCSP package option doesn’t provide
access to A_OUT0. Consequently, only A_OUT1 is available
as an analog output. When using this package, careful design
consideration must be taken to ensure that the desired signal
is available on Channel 1, i.e. on the A_OUT1 pin.
A third output stage option is available on
BelaSigna R262; using the Class−D output driver which can
drive an output transducer without the need for a separate
power amplifier. The output driver can also be configured
When interfacing BelaSigna R262 with other processors
like codecs or baseband chipsets, it is not recommended to
use the Class−D output driver, but rather the analog outputs.
Clock Generation Circuitry
BelaSigna R262 is equipped with a fully configurable and
flexible clocking system, which allows for many clocking
configurations for various use cases. Computing
applications typically require the use of a DMIC interface,
which requires the BelaSigna R262 clocking system to
provide full synchronization between an incoming DMIC
clock and the DMIC data that the chip will produce. The
clock frequencies that these systems usually operate with are
in the range of 2.048 to 3.072 MHz. Mobile phone
applications would typically use much higher clock
frequencies; historically, baseband systems have been using
13 MHz or 26 MHz, or even 19.2 MHz or 38.4 MHz.
To support such a wide variety of clocking scenarios,
BelaSigna R262 has a phase locked loop (PLL) integrated as
one of the components of its clock generation circuitry.
Clock frequencies can be selected using the CLOCK_SEL
pin, as discussed previously. BelaSigna R262 can also
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BelaSigna R262
For more information on the configuration of this
clocking architecture, refer to the BelaSigna R262
Communications and Configuration Guide.
operate on its internal RC oscillator, offering the same
performance, with the slight drawback that the sampling
frequency will vary from device to device due to process
variation affecting the RC oscillation frequency. When
BelaSigna R262 is used with its analog outputs, this has no
affect on performance and can be used safely. When
synchronization with an external system is required, such as
a DMIC codec, it is not possible to use the internal oscillator.
Power Supply Unit
BelaSigna R262 uses multiple power supplies as can be
seen on the simplified representation of the power supply
unit in Figure 10.
1.8 V
VDDD
Regulator
VDDD
1V
Bandgaps
&
Regulators
VREG
2V
Charge
Pump
VREG
Regulator
VDDA
POR & Power
Supervision
VBATRCVR VDDO VBAT
M
U
X
VMIC
CAP0 CAP1 VSSD VSSA
Figure 10. Power Supply Structure
Table 12 provides a short description of all the power
supply pins of BelaSigna R262.
Digital and analog sections of the chip have their own
power supplies to allow exceptional audio quality. Several
band gap reference circuits and voltage regulators are used
to separate the power supplies to the various blocks that
compose the BelaSigna R262 architecture.
Table 12. POWER SUPPLY VOLTAGES
Voltage
Abbreviation
Description
Battery Supply
Voltage
VBAT
The primary voltage supplied to BelaSigna R262 is VBAT. It is typically in the range 1.8 V – 3.3 V.
BelaSigna R262 has internal voltage regulators that allow the application PCB to avoid the use of
external voltage regulators.
Output Driver
Supply Voltage
VBATRCVR
If powered independently and the output driver is to be used, VBATRCVR must be connected to
VBAT on the application PCB. Alternatively, if the analog outputs are used, VBATRCVR should be
connected to VDDA. A decoupling capacitor is only required when the output driver is being used.
Internal Digital
Supply Voltage
VDDD
The internal digital supply voltage is used as the supply voltage for all internal digital components,
including being used as the interface voltage at the internal side of the level translation circuitry
attached to all of the digital pins. VDDD is provided as an output pad, where a decoupling capacitor to ground must be placed to filter power supply noise.
External I/O
Supply Voltage
VDDO
VDDO is an externally provided power source. It is used by BelaSigna R262 as the external side
of the level translation circuitry attached to all of the digital pins. Communication with external
devices on digital pins will happen at the level defined on this pin.
Regulated
Supply Voltage
VREG
VREG is a 1 V reference to the analog circuitry. It is available externally to allow for additional
noise filtering of the regulated voltages within the system. VREG can also be used as a microphone power supply, when the VMIC pin cannot be used.
Analog Supply
Voltage
VDDA
VDDA is a 2 V reference voltage generated from the internal charge pump. It is a reference to the
analog circuitry. It is available externally to allow for additional noise filtering of the regulated
voltages within the system. The internal charge pump uses an external capacitor that is periodically refreshed to maintain the 2 V supply. VDDA can also be used as a microphone power supply,
when the VMIC pin cannot be used.
Microphone
Bias Voltage
VMIC
VMIC is a configurable microphone bias voltage. VMIC can be configured by the application to
provide a 1 V or 2 V power supply to the microphones. It can also be grounded or put to High−Z
mode to save power when the microphones don’t have to be used. The ROM−based application
configures VMIC to provide 2 V to the microphones when they are in use, and High−Z when the
system is in Sleep mode.
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BelaSigna R262
Power Management Strategy & Battery Monitoring
clock, and take the appropriate actions whenever it disappears.
See the system monitoring section for more information.
BelaSigna R262 has a built−in power management unit
that guarantees valid system operation under any voltage
supply condition to prevent any unexpected audio output as
the result of any supply irregularity. The unit constantly
monitors the power supply and shuts down all functional
units (including all units in the audio path) when the power
supply voltage goes below a level at which point valid
operation can no longer be guaranteed.
The power management unit on BelaSigna R262 includes
power−on−reset (POR) functionality as well as power
supervisory circuitry, as shown in Figure 10. These two
components work together to ensure proper device
operation under all supply conditions.
The POR sequence is designed to ensure proper system
behavior during start−up and proper system configuration
after start−up. At the start of the POR sequence, the audio
output is disabled and all configuration and control registers
are asynchronously reset to their default values.
The power supervisory circuitry monitors the supply
voltage (VBAT). This circuit is used to start the system when
VBAT reaches a safe startup voltage, and to reset the system
when it drops below a relevant voltage threshold. The
relevant parameters are shown in Table 13.
Digital Communication Interfaces
Debug Port (UART)
BelaSigna R262 has an RS232−based UART that can be
used to interface the chip from ON Semiconductor’s
communication tools. The debug port cannot be used for
customer applications. BelaSigna R262 can only be
configured using the I2C interface. See the I2C interface
section for information on how communication tools can
interface with BelaSigna R262.
General−Purpose Input Output (GPIO)
BelaSigna R262 has five GPIO pins which are all used
with specific functionalities. The five signals are SPI_CLK/
CLOCK_SEL,
SPI_CS/BOOT_SEL,
SPI_SERO/
CHAN_SEL, SPI_SERI/ALPHA_SEL and SWAP_CHAN.
SWAP_CHAN is used as a GPIO, consequently, it has an
internal pull*up resistor. When used as LSADs
(CLOCK_SEL,
BOOT_SEL,
CHAN_SEL
and
ALPHA_SEL), the pull*ups are disabled. If left floating in
LSAD mode, the pins have a weak pull*down to ground.
See the Booting Control, Output and Channel Control and
Algorithm Control sections earlier in this document for
details on the behavior of these GPIO and LSAD pins.
Table 13. POWER MANAGEMENT PARAMETERS
Parameters
Voltage Level
VBAT startup
1.65 V ± 80 mV
VBAT shutdown
1.6 V ± 50 mV
Serial Peripheral Interface (SPI) Port
An SPI port is available on BelaSigna R262 for
applications such as communication with non−volatile
memory (EEPROM). The I/O levels on this port are defined
by the voltage on the VDDO pin. The SPI port operates in
master mode only, which supports communications with
slave SPI devices. The four signals needed by the SPI port
are multiplexed with other functions on BelaSigna R262
(GPIOs, LSADs). The use of the SPI port requires careful
design consideration with regards to the use of these other
functions.
The POR sequence consists of two phases: voltage supply
stabilization and boot ROM initialization. During the voltage
supply stabilization phase, the following steps are performed:
1. The internal regulators are enabled and allowed to
stabilize
2. The internal charge pump is enabled and allowed
to stabilize
3. SYSCLK is connected to all of the system
components (free−running PLL output)
4. The system runs the ROM application
At step 1, once the supply voltage rises above the startup
voltage and remains there for more than 5 ms, a signal will
enable the charge pump.
At step 2, another 5 ms delay is implemented to allow the
charge pump to stabilize before toggling the POR signal, and
thus enabling the digital core.
If the supply is consistent, the internal system voltage will
then remain at a fixed nominal voltage. If a spike occurs that
causes the voltage to drop below the shutdown internal
system voltage, the system will shut down. If the voltage
rises again above the startup voltage and remains there for
the required time, a POR sequence will occur again.
Once the ROM application is running, more system
monitoring is performed by the application; typically, the
software will permanently monitor the presence of an external
I2C Interface
The I2C interface is an industry*standard interface that
can be used for high*speed transmission of data between
BelaSigna R262 and an external device. The interface
operates at speeds up to 400 kbit/sec. In product
development mode, the I2C interface is used for application
debugging
purposes,
communicating
with
the
BelaSigna R262 development tools, also known as
SignaKlara Development Utility (SKDU). The interface
always operates in slave mode and the slave address is 0x61.
A comprehensive command interface can be used with the
SKDU and other tools provided by ON Semiconductor. It
will offer a variety of support functions grouped in different
categories like general system control (system reset, status
information), application control (switching between
operating modes, enabling or disabling the algorithm),
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21
BelaSigna R262
Interfaces Unused by the ROM−based Application
hardware setup (for custom configuration of the various
hardware units like clocking, input/output stages),
algorithm setup (amplitude management, tuning selection)
and finally the low*level I2C protocol is also supported.
The I2C interface can also be used to communicate with
a slave I2C EEPROM. Using an I2C EEPROM instead of an
SPI EEPROM provides better flexibility as it avoids
potential conflicts between GPIO/LSAD pins and the SPI
pins. More details on this command interface can be found
in the BelaSigna R262 Communications and Configuration
Guide.
BelaSigna R262 also contains hardware provisions for a
high speed PCM interface, as well as a high speed UART.
These two interfaces are not used by the ROM−based
application, hence cannot be used by default. Custom
applications developed by ON Semiconductor could enable
the use of these interfaces, should this be required.
Miscellaneous
Chip Identification
Long Term Storage Conditions
Chip identification information can be retrieved by using
the Communications Accelerator Adaptor (CAA) along
with protocol software provided by ON Semiconductor. For
BelaSigna R262, the key identifier components and values
are as follows:
ON Semiconductor specifies a 24−month maximum
storage time for WLCSP devices in pocket tapes and
conditioned in dry bags, as stated in Table 14 below and
defined by ON Semiconductor’s guidelines on long term
storage.
Chip Family
Chip Version
0x02 (SK2)
0x3021
Table 14. LONG TERM STORAGE CONDITIONS
Storage Condition
Maximum Storage Time
Remarks
Temperature 18−28°C,
Humidity 30−65%RH
24 months after die
singulation/sawing date
Maximum 12 months storage at condition 18−28°C, 30−65%RH. Afterwards storage in vacuum moisture bag with desiccant and humidity card.
Storage in nitrogen cabinet allowed.
Device Weight
WLCSP should all be covered in soldermask. The assembly
process can use underfill under the WLCSP; it will provide
another physical dielectric barrier, and will also enhance
long term reliability over temperature and physical shock.
ON Semiconductor can provide BelaSigna R262
mounting footprint guidelines to assist your PCB design
upon request. For additional information on the use of Chip
Scale Packages and for advanced guidelines on mounting
such devices to a PCB, please download AND8081/D −
Flip−Chip CSP Packages from www.onsemi.com.
BelaSigna R262 has an average weight of 10.84 mg.
Re−Flow Information
BelaSigna R262 is a Green, Pb−Free device. Download
SOLDERRM/D − Soldering and Mounting Techniques
Reference Guide.
Assembly / Design Notes
For PCB manufacture with the 26−ball WLCSP version of
BelaSigna R262, any vias that might be placed below the
Table 15. ORDERING INFORMATION
Device
Marking
Package
Shipping †
BR262W30A103E1G
BR262W30
WLCSP30
(Pb−Free)
2500 / Tape & Reel
BR262W26A103E1G
BR262W26
WLCSP26
(Pb−Free)
2500 / Tape & Reel
†For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging
Specification Brochure, BRD8011/D.
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22
BelaSigna R262
PACKAGE DIMENSIONS
WLCSP30, 2.233x2.388
CASE 567CT
ISSUE A
D
PIN A1
REFERENCE
2X
0.10 C
2X
ÈÈ
ÈÈ
0.10 C
A
NOTES:
1. DIMENSIONING AND TOLERANCING PER
ASME Y14.5M, 1994.
2. CONTROLLING DIMENSION: MILLIMETERS.
3. COPLANARITY APPLIES TO SPHERICAL
CROWNS OF SOLDER BALLS.
B
DIM
A
A1
A2
b
D
E
eA
eB
E
TOP VIEW
MILLIMETERS
MIN
MAX
0.84
1.00
0.17
0.23
0.72 REF
0.24
0.29
2.388 BSC
2.233 BSC
0.252 BSC
0.310 BSC
A2
0.10 C
A
0.05 C
NOTE 3
C
SIDE VIEW
A1
eA
RECOMMENDED
SOLDERING FOOTPRINT*
SEATING
PLANE
PACKAGE
OUTLINE
b
30X
0.05 C A B
0.03 C
A
B
0.310
eB
C
D
A1
E
F
G
1 2 3 4 5 6 7 8 9
BOTTOM VIEW
30X
0.504
PITCH
0.25
DIMENSIONS: MILLIMETERS
*For additional information on our Pb−Free strategy and soldering
details, please download the ON Semiconductor Soldering and
Mounting Techniques Reference Manual, SOLDERRM/D.
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23
BelaSigna R262
PACKAGE DIMENSIONS
WLCSP26, 2.388x2.233
CASE 567CY
ISSUE A
D
A
NOTES:
1. DIMENSIONING AND TOLERANCING PER
ASME Y14.5M, 1994.
2. CONTROLLING DIMENSION: MILLIMETERS.
3. COPLANARITY APPLIES TO SPHERICAL
CROWNS OF SOLDER BALLS.
B
DIM
A
A1
A2
b
D
E
eD
eE
E
PIN A1
REFERENCE
2X
0.10 C
2X
ÈÈ
0.10 C
TOP VIEW
MILLIMETERS
MIN
MAX
0.84
1.00
0.17
0.23
0.72 REF
0.24
0.29
2.388 BSC
2.233 BSC
0.252 BSC
0.310 BSC
A2
0.10 C
A
0.05 C
NOTE 3
C
SIDE VIEW
A1
eD
RECOMMENDED
SOLDERING FOOTPRINT*
SEATING
PLANE
PACKAGE
OUTLINE
b
26X
0.05 C A B
0.03 C
A
B
0.31
eE
C
D
A1
E
F
26X
0.504
PITCH
G
1 2 3 4 5 6 7 8 9
BOTTOM VIEW
0.25
DIMENSIONS: MILLIMETERS
*For additional information on our Pb−Free strategy and soldering
details, please download the ON Semiconductor Soldering and
Mounting Techniques Reference Manual, SOLDERRM/D.
BELASIGNA is a registered trademark of Semiconductor Components Industries, LLC.
ON Semiconductor and
are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC owns the rights to a number of patents, trademarks,
copyrights, trade secrets, and other intellectual property. A listing of SCILLC’s product/patent coverage may be accessed at www.onsemi.com/site/pdf/Patent−Marking.pdf. SCILLC
reserves the right to make changes without further notice to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any
particular purpose, nor does SCILLC assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without
limitation special, consequential or incidental damages. “Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications
and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. SCILLC
does not convey any license under its patent rights nor the rights of others. SCILLC products are not designed, intended, or authorized for use as components in systems intended for
surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where
personal injury or death may occur. Should Buyer purchase or use SCILLC products for any such unintended or unauthorized application, Buyer shall indemnify and hold SCILLC and
its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly,
any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that SCILLC was negligent regarding the design or manufacture
of the part. SCILLC is an Equal Opportunity/Affirmative Action Employer. This literature is subject to all applicable copyright laws and is not for resale in any manner.
PUBLICATION ORDERING INFORMATION
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ON Semiconductor Website: www.onsemi.com
Order Literature: http://www.onsemi.com/orderlit
For additional information, please contact your local
Sales Representative
BR262/D