AMS AS1312 Datasheet
The AMS AS1312 is an ultra-low quiescent current, hysteretic DC-to-DC step-up converter designed to operate from a +0.7V to +5.0V supply. With an efficiency of up to 94%, it's ideal for single Li-Ion battery-powered applications. The device features a wide input voltage range, extended battery life, and a low shutdown current of less than 100nA. Its fixed output voltage range of 2.5V to 5.0V and peak output current of 200mA make it suitable for various end applications, including handheld devices and battery-powered products.
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AS1312
Ultra Low Quiescent Current,
Hysteretic DC-DC Step-Up Converter
General Description
The AS1312 is an ultra low I
Q
hysteretic step-up DC-DC converter.
The AS1312 achieves an efficiency of up to 94% and is designed to operate from a +0.7V to +5.0V supply, the output voltage is fixed in 50mV steps from +2.5V to 5.0V.
In order to save power the AS1312 features a shutdown mode, where it draws less than 100nA. In shutdown mode the battery is not connected to the output.
If the input voltage exceeds the output voltage the device is in a feedthrough mode and the input is directly connected to the output voltage.
In light load operation, the device enters a sleep mode when most of the internal operating blocks are turned off in order to save power. This mode is active approximately 50μs after a current pulse provided that the output is in regulation.
The AS1312 also offers an adjustable low battery detection. If the battery voltage decreases below a threshold defined by two external resistors on pin LBI, the LBO output is pulled to logic low. LBO is working as Power-OK when LBI is connected to GND.
The AS1312 is available in a 8-pin (2x2) TDFN and a 0.4mm pitch
8-pin WL-CSP package.
and
Content Guide appear at end of
datasheet.
Figure 1:
Added Value of Using AS1312
Benefits
• Ideal for single Li-Ion battery powered applications
• Extended battery life
• Less power consumption
• Supports a variety of end applications
Key Benefits & Features
The benefits and features of AS1312, Ultra Low Quiescent
Current, Hysteretic DC-DC Step-Up Converter are listed below:
Features
• Wide input voltage range (0.7V to 5.0V)
• Feedthrough mode when V
IN
> V
OUT
• High efficiency up to 94%
• Low quiescent current of typ. 1
μ
A
• Low shutdown current of less than 100nA
• Fixed output voltage range (2.5V to 5.0V)
• Peak output current of 200mA
• Output disconnect in shutdown
ams Datasheet
[v1-19] 2016-Apr-14
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AS1312 −
General Description
Benefits
• Over temperature protection and shutdown
• Early power-fail warning
• Cost effective, small package
Features
• Integrated temperature monitoring
• Low battery detection
• 8-pin WL-CSP with 0.4mm pitch
• 8-pin TDFN (2mm x 2mm)
Applications
The AS1312 is an ideal solution for:
• Handheld devices
• Battery powered products
Block Diagram
The functional blocks of this device are shown below:
Figure 2:
AS1312 Block Diagram
V
IN
0.7V to 5.0V
LX
L1 6.8µF
LBI
ON
OFF
EN
VIN
C
IN
22µF
GND
Zero
Crossing
Detector
AS1312
Driver &
Control
Logic
Imax
Detection
-
+
VREF
Startup
Circuitry
0.6V
92.5% VREF
-
+
+
100mV
VOUT
C
OUT
22µF
V
OUT
2.5V to 5.0V
R3
100 k
LBO
REF
C
REF
100nF
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AS1312 −
Pin Assignment
Pin Assignment
Figure 3:
Pinout (Top View)
LBI 1
GND 2
LX 3
VOUT 4
AS1312
TDFN 8-pin 2x2mm
Exposed pad: GND
9
8 VIN
7 EN
6 LBO
5 REF
Pin A1 indicator
A1
LBI
B1
VIN
A2
GND
B2
EN
A3
LX
B3
LBO
A4
VOUT
B4
REF
Figure 4:
Pin Description
Pin Number
WL-CSP TDFN
Pin Name
A1
A2
A3
A4
B4
B3
1
2
3
4
5
6
LBI
GND
LX
VOUT
REF
LBO
B2
B1
-
7
8
9
EN
VIN
NC
Description
Low Battery Comparator Input
. 0.6V Threshold. May not be left floating. If connected to GND, LBO is working as Power Output OK.
Ground
External Inductor Connector.
Output Voltage.
Decouple VOUT with a ceramic capacitor as close as possible to VOUT and
GND
.
Reference Pin.
Connect a 100nF ceramic capacitor to this pin.
Low Battery Comparator Output
. Open-drain output.
Enable Pin
. Logic controlled shutdown input.
1 = Normal operation;
0 = Shutdown; shutdown current <100nA.
Battery Voltage Input.
Decouple VIN with a ceramic capacitor as close as possible to VIN and GND.
Exposed Pad.
This pad is not connected internally. Can be left floating or connect to
GND
to achieve an optimal thermal performance.
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[v1-19] 2016-Apr-14
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AS1312 −
Absolute Maximum R atings
Absolute Maximum Ratings
Stresses beyond those listed in
cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in
Characteristics is not implied. Exposure to absolute maximum
rating conditions for extended periods may affect device reliability.
Figure 5:
Absolute Maximum Ratings
Symbol
ESD
HBM
θ
T
AMB
T
J
T
STRG
T
BODY
RH
NC
Parameter Min Max Unit Comments
Electrical Parameters
VIN, VOUT, EN, LBI, LBO to
GND
LX, REF to GND
Input Current
(latch-up immunity)
-0.3
-0.3
-100
V
OUT
7
+ 0.3
100
V
V mA JEDEC 78
Electrostatic Discharge HBM
Electrostatic Discharge
±2 kV MIL 883 E method 3015
Thermal
Resistance
Temperature Ranges and Storage Conditions
WL-CSP 97
ºC/W
TDFN 60
Operating Temperature -40 85 ºC
Junction
Temperature
WL-CSP
TDFN
Storage Temperature Range
WL-CSP
-55
-55
125
150
150
125
ºC
ºC
ºC
ºC for 8-pin (2x2) TDFN for 8-pin WL-CSP
IPC/JEDEC J-STD-020
Package Body
Temperature
TDFN
260 ºC
IPC/JEDEC J-STD-020
The lead for Pb-free leaded packages is matte tin (100%
Sn)
Relative Humidity
(non-condensing)
5 85 %
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AS1312 −
Electrical Characteristics
Symbol
MSL
Parameter
WL-CSP
Moisture
Sensitivity Level
TDFN
Min
1
Max Unit Comments
Represents an unlimited floor life time
Represents an unlimited floor life time
Note(s) and/or Footnote(s):
1. Junction-to-ambient thermal resistance is very dependent on application and board-layout. In situations where high maximum power dissipation exists, special attention must be paid to thermal dissipation during board design.
2. The reflow peak soldering temperature (body temperature) is specified according IPC/JEDEC J-STD-020 “Moisture/Reflow Sensitivity
Classification for Nonhermetic Solid State Surface Mount Devices”
Electrical Characteristics
All limits are guaranteed. The parameters with Min and Max values are guaranteed by production tests or SQC (Statistical
Quality Control) methods.
V
IN
= 1.5V, C1 = C2 = 22μF, C
REF
= 100nF, Typical values are at
T
AMB
= 25ºC. Unless otherwise specified.
All limits are guaranteed.
The parameters with min and max values are guaranteed with production tests or SQC (Statistical Quality Control) methods.
Figure 6:
Electrical Characteristics
Symbol
V
IN
V
OUT
I
Q
Parameter Conditions
Input
Input Voltage Range
Minimum Startup Voltage T
AMB
= 25°C
Regulation
Output Voltage Range
Output Voltage Tolerance
V
OUT
Lockout Threshold
Quiescent Current V
Quiescent Current V
IN
OUT
I
LOAD
= 0mA to 10mA,
T
AMB
= 25°C
I
LOAD
= 0mA to 10mA
I
LOAD
= 0mA to 30mA,
T
AMB
= -20°C to 60°C
Rising Edge
Operating Current
V
OUT
= 1.02xV
OUTNOM
,
REF = 0.99xV
OUTNOM
,
T
AMB
= 25°C
V
OUT
= 5V, No load,
T
AMB
= 25°C
Min
0.7
-4
-2
2.5
-2
0.7
Typ
0.9
2.45
1
Max Unit
5.0
4
2
5.0
2
%
%
V
%
V
100 nA
1.3
V
V
μA
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AS1312 −
Electrical Characteristics
Symbol
I
QSHDN
R
ON
I
PEAK
V
ENH
V
ENL
I
EN
I
REF
V
LBI
I
LBI
V
LBO
I
LBO
Parameter
Shutdown Current
NMOS
PMOS
NMOS maximum on-time
Peak current limit
Zero crossing current
EN input voltage ‘high’
EN input voltage ‘low’
EN input bias current
REF input bias current
LBI threshold
LBI hysteresis
LBI leakage current
LBO voltage low
LBO leakage current
Power-OK threshold
Conditions
T
AMB
=
25ºC
Switches
Min Typ Max Unit
100 nA
V
OUT
= 5V
3.3
5
0.4
0.45
4.0
400
20
4.6
35
Enable, Reference
0.7
EN = 5V, T
AMB
= 25°C
REF = 0.99xV
OUTNOM
,
T
AMB
= 25°C
Low Battery & Power-OK
Falling edge 0.57
0.6
25
LBI
≤
V
IN
or V
OUT
(which ever is higher), T
AMB
= 25°C
I
LBO
= 1mA
T
AMB
= 25°C
LBI = 0V, Falling Edge
Thermal Protection
10°C Hysteresis
87
5
91
150
0.1
100
100
100
20
100
95
0.63
V mV nA mV nA
%
°C
V
V nA nA
Ω
Ω
μs mA mA
Caution:
Do not apply full load current until the device output > 2.5V
Note(s) and/or Footnote(s):
1. The regulator is in startup mode until this voltage is reached.
2. LBO goes low in startup mode as well as during normal operation if,
(i) The voltage at the LBI pin is lower than LBI threshold.
(ii) The voltage at the LBI pin is below 0.1V (connected to GND) and VOUT is below 92.5% of its nominal value.
3. Further switching is inhibited.
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AS1312 −
Typical Operating Characteristics
Typical Operating
Characteristics
V
OUT
= 5.0V,
T
AMB
= 25°C, unless otherwise specified.
Figure 7:
Efficiency vs. Output Current
100
90
80
70
60
50
40
30
20
10
0
0.001
L1: LPS4018-682M
0.01
0.1
1
Output Current (mA)
10
Vin = 0.9V
Vin = 1.5V
Vin = 2.5V
Vin = 4.0V
100
Figure 8:
Efficiency vs. Output Current
100
90
80
70
60
50
40
30
20
10
0
0.001
L1: XPL2010-682M
0.01
0.1
1
Output Current (mA)
10
Vin = 0.9V
Vin = 1.5V
Vin = 2.5V
Vin = 4.0V
100
ams Datasheet
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AS1312 −
Typical Operating Characteristics
Figure 9:
Efficiency vs. Input Voltage
100
90
80
70
60
50
40
L1: XPL2010-682M
30
20
Iout = 1mA
Iout=10mA
Iout=50mA
Iout=100mA
10
0
0.5
1 1.5
2 2.5
3 3.5
4 4.5
5
Input Voltage (V)
Figure 10:
Maximum Output Current vs. Input Voltage
200
175
150
125
100
75
50
25
0
1 1.5
2 2.5
3
Input Voltage (V)
3.5
4 4.5
ams Datasheet
[v1-19] 2016-Apr-14
AS1312 −
Typical Operating Characteristics
Figure 11:
Start-Up Voltage vs. Output Current
1
0.95
0.9
0.85
0.8
0.75
0.7
0.65
0.6
0.55
0.5
0 1 2 3 4 5 6 7
Output Current (mA)
8 9 10
Figure 12:
Output Voltage Ripple; V
IN
= 2V, R load
= 100
Ω
5µs/Div
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Detailed Description
AS1312 −
Detailed Description
Hysteretic Boost Converter
Hysteretic boost converters are so called because comparators are the active elements used to determine on-off timing via current and voltage measurements. There is no continuously operating fixed oscillator, providing an independent timing reference. As a result, a hysteretic or comparator based converter has a very low quiescent current. In addition, because there is no fixed timing reference, the operating frequency is determined by external component (inductor and capacitors) and also the loading on the output.
Ripple at the output is an essential operating component. A power cycle is initiated when the output regulated voltage drops below the nominal value of V
OUT
(0.99 x V
OUT
).
Inductor current is monitored by the control loop, ensuring that operation is always dis-continuous.
The application circuit shown in
will support many requirements. However, further optimization may be useful, and the following is offered as a guide to changing the passive components to more closely match the end requirement.
Input Loop Timing
The input loop consists of the source dc supply, the input capacitor, the main inductor, and the N-channel power switch.
The on timing of the N-channel switch is determined by a peak current measurement or a maximum on time. In the AS1312, peak current is 400mA (typ) and maximum on time is 4.2μs (typ).
Peak current measurement ensures that the on time varies as the input voltage varies. This imparts line regulation to the converter.
The fixed on-time measurement is something of a safety feature to ensure that the power switch is never permanently on. The fixed on-time is independent of input voltage changes. As a result, no line regulation exists.
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AS1312 −
Detailed Description
Figure 13:
Simplified Boost DC-DC Architecture
V
IN
C
IN
L1
SW1
SW2
Q
Q
I
PK
GND
FB
0V
C
OUT
V
OUT
R
LOAD
0V
On time of the power switch (Faraday’s Law) is given by:
(EQ1)
T
ON
=
IN
–
(
I
PK
R
SW
1
+
I
PK
R
L
1
)
sec [volts, amps, ohms, Henry]
(EQ2)
Applying Min and Max values and neglecting the resistive voltage drop across L1 and SW1;
T
ON
_
MIN
=
L
MIN
I
PK
_
MIN
V
IN
_
MAX
(EQ3)
T
ON
_
MAX
=
L
MAX
I
PK
_
MAX
V
IN
_
MIN
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AS1312 −
Detailed Description
Figure 14:
Simplified Voltage and Current Waveforms
V
0.99V
OUT_NOM
V
OUT
V
IND_TOFF
B
V
IND_TON
V
IN
0
C D A
B
C D
I
PK
0
I
L
T
OFF
T
WAIT
T
ON
SW1_on
SW2_off
T
T
OFF
T
SW2_on
SW1_off
T
WAIT
V
OUT
Ripple
T
T
Another important relationship is the “volt-seconds” law.
Expressed as following:
(EQ4)
V
ON
T
ON
=
V
OFF
T
OFF
Voltages are those measured across the inductor during each time segment.
Figure 14 shows this graphically with the shaded
segments marked “A & B”. Re-arranging
:
(EQ5)
T
T
OFF
=
V
V
–
IN
V
----------------------------
The time segment called T
WAIT
in
“hold-up” time of the output capacitor. While the output voltage is above the threshold (0.99xV
OUT
), the output is assumed to be in regulation and no further switching occurs.
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AS1312 −
Detailed Description
Inductor Choice Example
For the AS1312 V
IN_MIN
= 0.9V, V
OUT_MAX
T
ON
=2.66T
OFF
.
Let the maximum operating on-time = 1μs.
Note that this is shorter than the minimum limit on-time of
3.6μs. Therefore from
OFF
= 0.376μs. Using
MAX is obtained:
L
MAX
= 1.875μH. The nearest preferred value is 2.2μH.
This value provides the maximum energy storage for the chosen fixed on-time limit at the minimum V
IN
.
Energy stored during the on time is given by:
(EQ6)
E
= 0.5
L I
PK
)
2
Joules (Region A in
)
If the overall time period (T
ON
+ T
OFF
) is T, the power taken from the input is:
(EQ7)
P
IN
=
0.5
L I
PK
)
T
2
Watts
Assume output power is 0.8 P
IN
to establish an initial value of operating period T.
T
WAIT
is determined by the time taken for the output voltage to fall to 0.99xV
OUT
. The longer the wait time, the lower will be the supply current of the converter. Longer wait times require increased output capacitance. Choose T
WAIT
= 10% T as a minimum starting point for maximum energy transfer. For very low power load applications, choose T
WAIT
≥ 50% T.
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AS1312 −
Detailed Description
Output Loop Timing
The output loop consists of the main inductor, P-channel synchronous switch (or diode if fitted), output capacitor and load. When the input loop is interrupted, the voltage on the LX pin rises (Lenz’s Law). At the same time a comparator enables the synchronous switch, and energy stored in the inductor is transferred to the output capacitor and load. Inductor peak current supports the load and replenishes the charge lost from the output capacitor. The magnitude of the current from the inductor is monitored, and as it approaches zero, the synchronous switch is turned off. No switching action continues until the output voltage falls below the output reference point
(0.99 x V
OUT
).
Output power is composed of the dc component (Region C in
(EQ8)
P
REGION_C
=
V
IN
I
PK
T
OFF
Output power is also composed of the inductor component
(Region B in
), neglecting efficiency loss:
(EQ9)
P
REGION_B
=
0.5
L I
)
2
T
Total power delivered to the load is the sum of
and
(EQ10)
P
TOTAL
=
V
IN
I
2
T
OFF
+
0.5
L I
)
2
T
From (EQ 3) (using nominal values) peak current is given by:
(EQ11)
I
PK
=
T
ON
L
V
-------------------
Substituting
(EQ 11) into (EQ 10) and re-arranging:
(EQ12)
P
TOTAL
=
V
2
IN
2
T
TL
ON
(
T
)
0.9T incorporates a wait time T
WAIT
= 10% T
Output power in terms of regulated output voltage and load resistance is:
(EQ13)
P
OUT
=
R
2
LOAD
ams Datasheet
[v1-19] 2016-Apr-14
AS1312 −
Detailed Description
(EQ14)
Combining
V
2
R
LOAD
=
V
2
IN
2
T
TL
ON
(
T
)η
Symbol
η
reflects total energy loss between input and output and is approximately 0.8 for these calculations. Use
plot duty cycle (T
ON
/T) changes for various output loadings and changes to V
IN
.
Input Capacitor Selection
The input capacitor supports the triangular current during the on-time of the power switch, and maintains a broadly constant input voltage during this time. The capacitance value is obtained from choosing a ripple voltage during the on-time of the power switch. Additionally, ripple voltage is generated by the equivalent series resistance (ESR) of the capacitor. For worst case, use maximum peak current values from the datasheet.
(EQ15)
C
IN
=
I
PEAK
T
V
RIPPLE
Using T
ON
= 1μs, and I
PEAK
= 400mA (typ), and V
RIPPLE
= 50mV,
EQ 15 yields:
C
IN
= 8.0μF
Nearest preferred would be 10μF.
(EQ16)
V
PK
_
RIPPLE
_
ESR
=
I
PK
R
ESR
Typically, the ripple due to ESR is not dominant. ESR for the recommended capacitors (Murata GMR), ESR = 5m
Ω
to 10m
Ω
.
For the AS1312, maximum peak current is 400mA. Ripple due to ESR is 2.0mV to 4.0mV.
Ripple at the input propagates through the common supply connections, and if too high in value can cause problems elsewhere in the system. The input capacitance is an important component to get right.
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AS1312 −
Detailed Description
Output Capacitor Selection
The output capacitor supports the triangular current during the off-time of the power switch (inductor discharge period), and also the load current during the wait time (Region D in
Figure 14 ) and on-time (Region A in Figure 14
) of the power switch.
(EQ17)
C
OUT
=
I
LOAD
( 1
−
0 .
(
T
ON
+
T
99 )
V
OUT
WAIT
_
NOM
)
Note(s):
There is also a ripple component due to the equivalent series resistance (ESR) of the capacitor.
Summary
User Application Defines:
V
IN min, V
IN max, V
OUT min, V
OUT max, I
LOAD min, I
LOAD max
Inductor Selection:
Select Max on-time = 0.5μs to 3μs for AS1312. Use (EQ 3) to
calculate inductor value.
Use
Use
(EQ 6) to check that power delivery matches load
requirements assume 70% conversion efficiency.
Use
(EQ 13) to find overall timing period value of T at min V
IN and max V
OUT
for maximum load conditions.
Input Capacitor Selection:
Choose a ripple value and use
Output Capacitor Selection:
Determine T
WAIT
via
or
to find the value.
ams Datasheet
[v1-19] 2016-Apr-14
AS1312 −
Application Information
Application Information
Figure 15:
Typical Application Diagram
The AS1312 is available with fixed output voltages from 2.5V to
5.0V in 50mV steps.
C
IN
V
IN
0.7V to 5.0V
22µF
ON
OFF
L1
6.8µH
LX
VIN
LBI
EN
AS131 2
LBO
OUT
REF
GND
C
REF
100 nF
Low Battery
Detect
V
OUT
2.5V to 5.0V
C
OUT
22µF
0V
AS1312 Features
Shutdown
The part is in shutdown mode while the voltage at pin EN is below 0.1V and is active when the voltage is higher than 0.7V.
Note(s):
EN can be driven above V
IN
or V
OUT
, as long as it is limited to less than 5.0V.
Output Disconnect
During shutdown V
OUT
is going to 0V and no current from the input source is running through the device.
Feedthrough Mode
If the input voltage is higher than the output voltage (and the
AS1312 is enabled) the supply voltage is connected to the load through the device. To guarantee a proper function of the
AS1312 it is not allowed that the supply exceeds the maximum allowed input voltage (5.0V).
In this feedthrough mode the quiescent current is 35μA (typ.).
The device goes back into step-up mode when the output voltage is 4% (typ.) below V
OUTNOM
.
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AS1312 −
Application Information
Power-OK and Low-Battery-Detect Functionality
LBO goes low in startup mode as well as during normal operation if:
• The voltage at the LBI pin is below LBI threshold (0.6V).
This can be used to monitor the battery voltage.
• LBI pin is connected to GND and V
OUT
is below 92.5% of its nominal value. LBO works as a power-OK signal in this case.
The LBI pin can be connected to a resistive-divider to monitor a particular definable voltage and compare it with a 0.6V internal reference. If LBI is connected to GND an internal resistive-divider is activated and connected to the output.
Therefore, the Power-OK functionality can be realized with no additional external components.
The Power-OK feature is not active during shutdown and provides a power-on-reset function that can operate down to
V
IN
= 0.7V. A capacitor to GND may be added to generate a power-on-reset delay. To obtain a logic-level output, connect a pull-up resistor R
3
from pin LBO to pin V
OUT
. Larger values for this resistor will help to minimize current consumption; a 100k
Ω resistor is perfect for most applications see
For the circuit shown in the left of
current into LBI is very low, permitting large-value resistor-divider networks while maintaining accuracy. Place the resistor-divider network as close to the device as possible. Use a defined resistor for R
2
and then calculate R
1
as:
(EQ18)
R
1
=
R
2
⋅
V
V
LBI
–
1
Where: VLB
I
is 0.6V
Figure 16:
Typical Application with Adjustable Battery Monitoring
V
IN
0.7V to 5.0V
C
IN
22µF
ON
OFF
L1
6.8µH
LX
VIN
LBI
EN
AS131 2
LBO
OUT
REF
GND
C
REF
100 nF
Low Battery
Detect
V
OUT
2.5V to 5.0V
C
OUT
22µF
0V
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AS1312 −
Application Information
Figure 17:
Typical Application with LBO Working as Power-OK
V
IN
0.7V to 5.0V
C
IN
22µF
ON
OFF
L1
6.8µH
LX
VIN
LBO
AS131 2
OUT
LBI
EN
REF
GND
C
REF
100 nF
Power OK
Output
V
OUT
2.5V to 5.0V
C
OUT
22µF
0V
Thermal Shutdown
To prevent the AS1312 from short-term misuse and overload conditions the chip includes a thermal overload protection. To block the normal operation mode all further switching is inhibited for output voltage above V
OUT
lockout threshold. The device is in thermal shutdown when the junction temperature exceeds 150°C. To resume the normal operation the temperature has to drop below 140°C.
A good thermal path has to be provided to dissipate the heat generated within the package. Otherwise it’s not possible to operate the AS1312 at its usable maximal power. To dissipate as much heat as possible from the package into a copper plane with as much area as possible, it’s recommended to use multiple vias in the printed circuit board. It’s also recommended to solder the Exposed Pad (pin 9) to the GND plane.
Note(s):
Continuing operation in thermal overload conditions may damage the device and is considered bad practice.
ams Datasheet
[v1-19] 2016-Apr-14
Page 19
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AS1312 −
Application Information
Component Selection
Only four components are required to complete the design of the step-up converter. The low peak currents of the AS1312 allow the use of low value, low profile inductors and tiny external ceramic capacitors.
Inductor Selection
For best efficiency, choose an inductor with high frequency core material, such as ferrite, to reduce core losses. The inductor should have low DCR (DC resistance) to reduce the I²R losses, and must be able to handle the peak inductor current without saturating. A 6.8μH inductor with a > 500mA current rating and
< 500m
Ω
DCR is recommended.
Figure 18:
Recommended Inductors
Part Number
ELLVEG6R8N
ELLVFG6R8MC
ELLVGG6R8N
LQH3NPN6R8MM0
LQH3NPN6R8NM0
LQH3NPN6R8MJ0
LQH3NPN6R8NJ0
LQH3NPN6R8MMR
VLS2012ET-6R8M
VLS252015ET-6R8M
VLS3010ET-6R8M
VLS3012ET-6R8M
VLS3015ET-6R8M
LPS4018-682ML
L
6.8
μ
H
6.8
μ
H
6.8
μ
H
6.8
μ
H
6.8
μ
H
6.8
μ
H
6.8
μ
H
6.8
μ
H
6.8
μ
H
6.8
μ
H
6.8
μ
H
6.8
μ
H
6.8
μ
H
6.8
μ
H
DCR
0.35Ω
0.23Ω
0.23Ω
0.24Ω
0.24Ω
0.252Ω
0.252Ω
0.186Ω
0.498Ω
0.48Ω
0.312Ω
0.228Ω
0.216Ω
0.15Ω
Current
Rating
0.58A
0.6A
1A
1A
1A
0.85A
0.85A
1.25A
0.57A
0.85A
0.69A
0.81A
0.92A
1.2A
Size in mm
(L/W/T)
3x3x1
3x3x1.2
3x3x1.5
3x3x1.4
3x3x1.4
3x3x1.1
3x3x1.1
3x3x1.1
2x2x1.2
2.5x2x1.5
3x3x1
3x3x1.2
3x3x1.5
Manufacturer
Panasonic www.industrial.panasonic.com
Murata www.murata.com
TDK www.tdk.com
4x4x1.7
Coilcraft www.coilcraft.com
Page 20
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AS1312 −
Application Information
Capacitor Selection
The convertor requires three capacitors. Ceramic X5R or X7R types will minimize ESL and ESR while maintaining capacitance at rated voltage over temperature. The V
IN
capacitor should be
22μF. The V
OUT
capacitor should be between 22μF and 47μF. A larger output capacitor should be used if lower peak to peak output voltage ripple is desired. A larger output capacitor will also improve load regulation on V
OUT
. See table below for a list of capacitors for input and output capacitor selection.
Figure 19:
Recommended Input and Output Capacitors
Part Number
GRM21BR60J226ME39L
GRM31CR61A226ME19L
12066D226KAT_A
1210ZD226KAT_A
1210YD226KAT_A
C2012X5R0J226K/1.25
C2012X5R1A226K/1.25
C2012X5R1C226K
C
22
μ
F
22
μ
F
22
μ
F
22
μ
F
22
μ
F
22
μ
F
22
μ
F
22
μ
F
TC
Code
X5R
X5R
X5R
X5R
X5R
X5R
X5R
X5R
Rated
Voltage
16V
6.3V
10V
16V
6.3V
10V
6.3V
10V
Size in mm
(L/W/T)
2x1.25x1.25
3.2x1.6x1.6
3.2x1.6x1.78
3.2x1.6x1.78
3.2x1.6x1.78
2x1.2x1.25
2x1.2x1.25
2x1.2x1.25
Manufacturer
Murata www.murata.com
AVX www.avx.com
TDK www.tdk.com
On the pin REF a 100nF capacitor with an
Insulation resistance >1G
Ω
is recommended.
Figure 20:
Recommended Capacitors for REF
Part Number C
GRM188R71C104KA01 100nF
TC
Code
X7R
Insulation
Resistance
>5G
Ω
Rated
Voltage
Dimensions
(L/W/T)
16V
Manufacturer
0603, T=0.8mm
Murata www.murata.com
ams Datasheet
[v1-19] 2016-Apr-14
Layout Considerations
Relatively high peak currents of 400mA (typ) circulate during normal operation of the AS1312. Long printed circuit tracks can generate additional ripple and noise that mask correct operation and prove difficult to “de-bug” during production testing. Referring to
, the input loop formed by C1, VIN and GND pins should be minimized. Similarly, the output loop formed by C2, VOUT and GND should also be minimized. Ideally both loops should connect to GND in a “star” fashion. Finally, it is important to return C
REF
to the GND pin directly.
Page 21
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AS1312 −
Pack age Drawings & Mark ings
Package Drawings & Markings
The device is available in a 8-pin (2x2) TDFN and 8-pin WL-CSP package.
Figure 21:
8-pin (2x2) TDFN Marking
XXX
YY
Figure 22:
8-pin WL-CSP Marking
YY
XXXX
Figure 23:
Packaging Code
XXX
Tracecode for TDFN
Page 22
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XXXX
Tracecode for WL-CSP
YY
Marking
ams Datasheet
[v1-19] 2016-Apr-14
AS1312 −
Package Drawings & Markings
Figure 24:
8-pin (2x2) TDFN Drawings and Dimensions
RoHS
Green
Note(s) and/or Footnote(s):
1. Dimensioning & tolerancing conform to
ASME Y14.5M-1994
.
2. All dimensions are in millimeters. Angles are in degrees.
3. Coplanarity applies to the exposed heat slug as well as the terminal.
4. Radius on terminal is optional.
5. N is the total number of terminals.
D2
E2 aaa bbb ccc ddd eee fff
N
E e b
D
A
A1
A3
L
s
Symbol Min Nom Max
0.51
0.00
0.55
0.02
0.25
2.00 BSC
0.60
0.05
0.15 REF
0.225
0.325
0.425
0.18
0.30
1.45
0.75
-
-
2.00 BSC
0.50 BSC
1.60
0.90
0.15
0.10
0.10
0.05
1.70
1.00
-
-
-
-
-
0.08
0.10
8
-
-
-
-
ams Datasheet
[v1-19] 2016-Apr-14
Page 23
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Figure 25:
8-pin WL-CSP Drawings and Dimensions
AS1312 −
Pack age Drawings & Mark ings
Die size excluding the scribeline: 1570 x 790µm
RoHS
Green
Dimensions Min [
μ
m] Nom [
μ
m] Max [
μ
m]
Package x-dimension
Package y-dimension
Package height
Bump height
Bump Diameter
Die thickness
1595
815
470
180
250
270
1615
835
500
200
270
275
1635
855
530
220
290
280
Note(s) and/or Footnote(s):
1. ccc Coplanarity.
2. All dimensions are in μm.
3. “Bottom view” and “top trough view” values indicate the die dimensions without scribe lines. The “die size after cutting” values gives the package dimensions with tolerance.
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ams Datasheet
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AS1312 −
Ordering & Contact Information
Ordering & Contact Information
The device is available as the standard products listed below.
Figure 26:
Ordering Information
Ordering Code
V
OUT
AS1312-BTDT-50
5.0V
AS1312-BTDM-50
Package
8-pin (2x2) TDFN
8-pin (2x2) TDFN
Marking Delivery Form Delivery Quantity
BE
Tape and Reel
Tape and Reel
10k pcs/reel
1k pcs/reel
AS1312-BTDT-33
AS1312-BTDM-33
3.3V
8-pin (2x2) TDFN
8-pin (2x2) TDFN
AS1312-BTDT-30
AS1312-BTDM-30
3.0V
8-pin (2x2) TDFN
8-pin (2x2) TDFN
AS1312-BTDT-27
AS1312-BTDM-27
2.7V
8-pin (2x2) TDFN
8-pin (2x2) TDFN
AS1312-BWLT-50
AS1312-BWLM-50
5.0V
8-pin WL-CSP
8-pin WL-CSP
AS1312-BWLT-45
AS1312-BWLM-45
4.5V
AS1312-BWLT-33
3.3V
AS1312-BWLM-33
AS1312
tbd
8-pin WL-CSP
8-pin WL-CSP
8-pin WL-CSP
8-pin WL-CSP tbd
BX
BY
C1
BF
BQ
CO tbd
Tape and Reel
Tape and Reel
Tape and Reel
Tape and Reel
Tape and Reel
Tape and Reel
Tape and Reel
Tape and Reel
Tape and Reel
Tape and Reel
Tape and Reel
Tape and Reel tbd
10k pcs/reel
1k pcs/reel
10k pcs/reel
1k pcs/reel
10k pcs/reel
1k pcs/reel
10k pcs/reel
1k pcs/reel
10k pcs/reel
1k pcs/reel
10k pcs/reel
1k pcs/reel tbd
Note(s) and/or Footnote(s):
1. Non-standard devices from 2.5V to 5.0V are available in 50mV steps.
The above figure shows the ordering codes for Tape & Reel deliveries (suffix
T
in the ordering code). It is also possible to have all the variants on mini reels, when the ordering codes are
AS1312-BTDM-xx or AS1312-BWLM (where suffix
M
stands for mini reel). The components are the same in both reel sizes.
ams Datasheet
[v1-19] 2016-Apr-14
Page 25
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AS1312 −
Ordering & Contac t Information
Buy our products or get free samples online at: www.ams.com/ICdirect
Technical Support is available at: www.ams.com/Technical-Support
Provide feedback about this document at: www.ams.com/Document-Feedback
For further information and requests, e-mail us at: [email protected]
For sales offices, distributors and representatives, please visit: www.ams.com/contact
Headquarters
ams AG
Tobelbaderstrasse 30
8141 Premstaetten
Austria, Europe
Tel: +43 (0) 3136 500 0
Website: www.ams.com
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ams Datasheet
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AS1312 −
RoHS Compliant & ams Green Statement
RoHS Compliant & ams Green
Statement
RoHS:
The term RoHS compliant means that ams AG products fully comply with current RoHS directives. Our semiconductor products do not contain any chemicals for all 6 substance categories, including the requirement that lead not exceed
0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, RoHS compliant products are suitable for use in specified lead-free processes.
ams Green (RoHS compliant and no Sb/Br):
ams Green defines that in addition to RoHS compliance, our products are free of Bromine (Br) and Antimony (Sb) based flame retardants
(Br or Sb do not exceed 0.1% by weight in homogeneous material).
Important Information:
The information provided in this statement represents ams AG knowledge and belief as of the date that it is provided. ams AG bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. ams AG has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. ams AG and ams AG suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
ams Datasheet
[v1-19] 2016-Apr-14
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Copyrights & Disclaimer
AS1312 −
Copyrights & Disclaimer
Copyright ams AG, Tobelbader Strasse 30, 8141 Premstaetten,
Austria-Europe. Trademarks Registered. All rights reserved. The material herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner.
Devices sold by ams AG are covered by the warranty and patent indemnification provisions appearing in its General Terms of
Trade. ams AG makes no warranty, express, statutory, implied, or by description regarding the information set forth herein. ams AG reserves the right to change specifications and prices at any time and without notice. Therefore, prior to designing this product into a system, it is necessary to check with ams AG for current information. This product is intended for use in commercial applications. Applications requiring extended temperature range, unusual environmental requirements, or high reliability applications, such as military, medical life-support or life-sustaining equipment are specifically not recommended without additional processing by ams AG for each application. This product is provided by ams AG “AS IS” and any express or implied warranties, including, but not limited to the implied warranties of merchantability and fitness for a particular purpose are disclaimed.
ams AG shall not be liable to recipient or any third party for any damages, including but not limited to personal injury, property damage, loss of profits, loss of use, interruption of business or indirect, special, incidental or consequential damages, of any kind, in connection with or arising out of the furnishing, performance or use of the technical data herein. No obligation or liability to recipient or any third party shall arise or flow out of ams AG rendering of technical or other services.
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ams Datasheet
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AS1312 −
Document Status
Document Status
Document Status
Product Preview
Preliminary Datasheet
Datasheet
Datasheet (discontinued)
Product Status
Pre-Development
Pre-Production
Production
Discontinued
Definition
Information in this datasheet is based on product ideas in the planning phase of development. All specifications are design goals without any warranty and are subject to change without notice
Information in this datasheet is based on products in the design, validation or qualification phase of development.
The performance and parameters shown in this document are preliminary without any warranty and are subject to change without notice
Information in this datasheet is based on products in ramp-up to full production or full production which conform to specifications in accordance with the terms of ams AG standard warranty as given in the General Terms of
Trade
Information in this datasheet is based on products which conform to specifications in accordance with the terms of ams AG standard warranty as given in the General Terms of
Trade, but these products have been superseded and should not be used for new designs
ams Datasheet
[v1-19] 2016-Apr-14
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AS1312 −
Revision Information
Revision Information
Changes from 1-18 (2014-Dec-15) to current revision 1-19 (2016-Apr-14)
Updated Figure 26
Note(s) and/or Footnote(s):
1. Page and figure numbers for the previous version may differ from page and figure numbers in the current revision.
2. Correction of typographical errors is not explicitly mentioned.
Page
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ams Datasheet
[v1-19] 2016-Apr-14
AS1312 −
Content Guide
Content Guide
1 General Description
1 Key Benefits & Features
2 Applications
2 Block Diagram
3 Pin Assignment
4 Absolute Maximum Ratings
5 Electrical Characteristics
7 Typical Operating Characteristics
10 Detailed Description
10 Hysteretic Boost Converter
10 Input Loop Timing
13 Inductor Choice Example
14 Output Loop Timing
15 Input Capacitor Selection
16 Output Capacitor Selection
16 Summary
17 Application Information
17 AS1312 Features
17 Shutdown
17 Output Disconnect
17 Feedthrough Mode
18 Power-OK and Low-Battery-Detect Functionality
19 Thermal Shutdown
20 Component Selection
20 Inductor Selection
21 Capacitor Selection
21 Layout Considerations
22 Package Drawings & Markings
25 Ordering & Contact Information
27 RoHS Compliant & ams Green Statement
28 Copyrights & Disclaimer
29 Document Status
30 Revision Information
ams Datasheet
[v1-19] 2016-Apr-14
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