FAN5341 Series Boost LED Driver with Integrated Schottky Diode

FAN5341 Series Boost LED Driver with Integrated Schottky Diode
Is Now Part of
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FAN5341
Series Boost LED Driver with Integrated Schottky Diode and
Single-Wire Digital Interface
Features
Description
ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
The FAN5341 is an asynchronous constant-current LED
driver capable of efficiently delivering up to 500mW to a
string of up to five LEDs in series. Optimized for small formfactor applications, the 1.2MHz fixed switching frequency
allows the use of small chip inductors and capacitors.
Asynchronous Boost Converter
Internal Schottky Diode
Up to 500mW Output Power
Drives 3 to 5 LEDs in Series
2.7V to 5.5V Input Voltage Range
Single-Wire Digital Control Interface to Set LED
Brightness Levels
− 32 Linear Steps
ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
1.2MHz Fixed Switching Frequency
Soft-Start Capability
Input Under-Voltage Lockout (UVLO)
Output Over-Voltage Protection (OVP)
The FAN5341 uses a simple single-wire digital control
interface to program the brightness levels of the LEDs in 32
linear steps by applying digital pulses.
For safety, the device features integrated over-voltage, overcurrent, short-circuit detection, and thermal-shutdown
protection. In addition, input under-voltage lockout protection
is triggered if the battery voltage is too low.
The FAN5341 is available in a very low profile, small formfactor 2mm x 2mm x 0.55mm 6-lead UMLP package that is
green and RoHS compliant.
Short-Circuit Detection
Thermal Shutdown (TSD) Protection
Low Profile 6-lead 2.0 x 2.0 x 0.55mm UMLP Package
Applications
ƒ
ƒ
ƒ
ƒ
Cellular Mobile Handsets
Mobile Internet Devices
Portable Media Players
PDA, DSC, MP3 Players
Ordering Information
Part Number
Temperature Range
Package
Packing
FAN5341UMPX
-40 to 85°C
6-lead, 2.0 x 2.0mm UMLP
Tape and Reel
© 2009 Fairchild Semiconductor Corporation
FAN5341 • Rev. 1.0.1
www.fairchildsemi.com
FAN5341 — Series Boost LED Driver with Integrated Schottky Diode and Single-Wire Digital Interface
August 2010
FAN5341 — Series Boost LED Driver with Integrated Schottky Diode and Single-Wire Digital Interface
Typical Application Diagram
Figure 1. Typical Application
Block Diagram
Figure 2. Functional Block Diagram
© 2009 Fairchild Semiconductor Corporation
FAN5341 • Rev. 1.0.1
www.fairchildsemi.com
2
VOUT 1
VIN
2
EN
3
P1
GND
6
GND
5
SW
4
FB
Figure 3. UMLP6 Package, ^Top View
Pin Definitions
Pin #
Name
Description
1
VOUT
Boost Output Voltage. Output of the boost regulator. Connect the LEDs to this pin. Connect COUT
(Output Capacitor) to GND.
2
VIN
Input Voltage. Connect to power source and decouple with CIN to GND.
3
EN
Enable Brightness Control. Program dimming levels by driving pin with digital pulses.
4
FB
Voltage Feedback. The boost regulator regulates this pin to 0.253V to control the LED string current.
Tie this pin to a current setting resistor (RSET) between GND and the cathode of the LED string.
5
SW
Switching node. Tie inductor L1 from VIN to SW pin.
6
GND
Ground. Tie directly to a GND plane.
© 2009 Fairchild Semiconductor Corporation
FAN5341 • Rev. 1.0.1
www.fairchildsemi.com
3
FAN5341 — Series Boost LED Driver with Integrated Schottky Diode and Single-Wire Digital Interface
Pin Configuration
Stresses exceeding the absolute maximum ratings may damage the device. The device may not function or be operable above
the recommended operating conditions and stressing the parts to these levels is not recommended. In addition, extended
exposure to stresses above the recommended operating conditions may affect device reliability. The absolute maximum ratings
are stress ratings only.
Symbol Parameter
Min.
Max.
Units
VIN
-0.3
6.0
V
FB, EN Pins
-0.3
VIN + 0.3
V
VSW
SW Pin
-0.3
22.0
V
VOUT
VOUT Pin
–0.3
22.0
V
ESD
Electrostatic Discharge Protection Human Body Model per JESD22-A114
Level
Charged Device Model per JESD22-C101
VIN
VFB, VEN
3.3
kV
2.0
TJ
Junction Temperature
-40
+150
°C
TSTG
Storage Temperature
-65
+150
°C
+260
°C
TL
Lead Soldering Temperature, 10 Seconds
Recommended Operating Conditions
The Recommended Operating Conditions table defines the conditions for actual device operation. Recommended operating
conditions are specified to ensure optimal performance to the datasheet specifications. Fairchild does not recommend exceeding
them or designing to absolute maximum ratings.
Symbol
VIN
Parameter
Comments
VIN Supply Voltage
(1)
VOUT
VOUT Voltage
IOUT
VOUT Load Current
Max.
Units
2.7
5.5
V
6.2
17.5
V
5
25
mA
TA
Ambient Temperature
-40
+85
°C
TJ
Note:
Junction Temperature
-40
+125
°C
1.
500mW Maximum Output Power
Min.
Application should guarantee that minimum and maximum duty-cycle should fall between 20-85% to meet the specified
range
Thermal Properties
Junction-to-ambient thermal resistance is a function of application and board layout. This data is measured with four-layer 2s2p
boards in accordance to JEDEC standard JESD51. Special attention must be paid not to exceed junction temperature TJ(max) at a
given ambient temperature TA.
Symbol Parameter
θJA
Junction-to-Ambient Thermal Resistance, UMLP6 Package
© 2009 Fairchild Semiconductor Corporation
FAN5341 • Rev. 1.0.1
Typical
Units
70
°C/W
www.fairchildsemi.com
4
FAN5341 — Series Boost LED Driver with Integrated Schottky Diode and Single-Wire Digital Interface
Absolute Maximum Ratings
VIN = 2.7V to 5.5V and TA = -40°C to +85°C unless otherwise noted. Typical values are at TA = 25°C and VIN = 3.6V.
Symbol
Parameter
Conditions
Min.
Typ.
Max.
Units
0.30
0.75
μA
2.35
2.15
2.60
2.40
V
Power Supplies
ISD
Shutdown Supply Current
EN = GND, VIN = 3.6V
VUVLO
Under-Voltage Lockout
Threshold
VIN Rising
VIN Falling
VUVHYST
Under-Voltage Lockout
Hysteresis
2.10
1.90
250
mV
EN: Enable Pin
VIH
HIGH-Level Input Voltage
VIL
LOW-Level Input Voltage
1.2
200
V
300
0.4
V
400
kΩ
300
µs
REN
EN Pull-Down Resistance
TLO
EN Low Time for Dimming
VIN = 3.6V; See Figure 14
0.5
THI
Time Delay Between Steps
VIN = 3.6V; See Figure 14
0.5
µs
TSD
EN Low, Shutdown Pulse Width
VIN = 3.6V; from Falling Edge of EN
1
ms
Feedback and Reference
VFB
Feedback Voltage
ILED = 20mA from -40°C to +85°C,
2.7V ≤ VIN ≤ 5.5V
IFB
Feedback Input Current
240
253
266
mV
VFB = 253mV
0.1
1.0
μA
VIN = 3.6V, ISW = 100mA
600
VIN = 2.7V, ISW = 100mA
650
SW Node Leakage
EN = 0, VIN = VSW = VOUT = 5.5V,
VLED = 0
0.1
Boost Switch Peak Current Limit
VIN = 3.6V
750
Power Outputs
RDS(ON)_Q1
ISW(OFF)
ILIM-PK
Boost Switch On-Resistance
(1)
mΩ
2.0
μA
mA
Oscillator
fSW
Boost Regulator Switching
Frequency
1.0
1.2
1.4
18.0
18.9
21.0
MHz
Output and Protection
VOVP
Boost Output Over-Voltage
Protection
OVP Hysteresis
V
0.8
VTLSC
VOUT Short Circuit Detection
Threshold
VOUT Falling
VIN – 1.4
V
VTHSC
VOUT Short Circuit Detection
Threshold
VOUT Rising
VIN – 1.2
V
DMAX
Maximum Boost Duty Cycle
(2,3)
85
(2,3)
DMIN
Minimum Boost Duty Cycle
TTSD
THYS
Thermal Shutdown
Thermal Shutdown Hysteresis
20
150
35
%
°C
°C
Notes:
1. SW leakage current includes the leakage current of 2 internal switches; SW to GND and SW to VOUT.
2. Not tested in production and guaranteed by design.
3. Application should guarantee that minimum and maximum duty cycle should fall between 20-85% to meet the specified
range.
© 2009 Fairchild Semiconductor Corporation
FAN5341 • Rev. 1.0.1
www.fairchildsemi.com
5
FAN5341 — Series Boost LED Driver with Integrated Schottky Diode and Single-Wire Digital Interface
Electrical Specifications
90
90
5 LEDs
L = 10µH
COUT = 1.0µF
ILED = 25mA
80
Efficiency (%)
Efficiency (%)
80
70
VIN=2.7V
60
5 LEDs
L = 4.7µH
COUT = 1.0µF
ILED = 25mA
70
60
VIN=2.8V
VIN=3.6V
VIN=3.6V
VIN=4.2V
VIN=4.2V
50
50
5
10
15
20
25
5
10
LED Current (mA)
Figure 4. 5 LEDs: Efficiency vs. LED Current
vs. Input Voltage
25
0.8
Delta Feedback Voltage (m V)
4 LEDs
L = 10µH
COUT = 1.0µF
ILED = 25mA
80
Efficiency (%)
20
Figure 5. 5 LEDs: Efficiency vs. LED Current
vs. Input Voltage
90
70
VIN=2.7V
60
VIN=3.6V
VIN=4.2V
50
0.6
0.4
0.2
0
-0.2
-40°C
+25°C
-0.4
+85°C
-0.6
5
10
15
20
25
2.7
3
LED Current (mA)
3.6
3.9
4.2
Figure 7. Delta of VFB Over Input Voltage and
Temperature for 4 LEDs with L=10µH and
COUT=1.0µF at ILED=25mA
90
20.0
3 LEDs
L = 10µH
COUT = 1.0µF
ILED = 25mA
80
3.3
Input Voltage (V)
Figure 6. 4 LEDs: Efficiency vs. LED Current
vs. Input Voltage
4 LEDs
L = 10µH
COUT = 1.0µF
ILED = 25mA
19.5
19.0
OVP (V)
Efficiency (%)
15
LED Current (mA)
70
18.5
18.0
60
VIN=2.8V
17.5
VIN=3.6V
VIN=4.2V
17.0
50
5
10
15
20
2.7
25
Figure 8. 3 LEDs: Efficiency vs. LED Current
vs. Input Voltage
© 2009 Fairchild Semiconductor Corporation
FAN5341 • Rev. 1.0.1
3
3.3
3.6
3.9
4.2
Input Voltage (V)
LED Current (mA)
Figure 9. Over-Voltage Protection vs. Input Voltage
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6
FAN5341 — Series Boost LED Driver with Integrated Schottky Diode and Single-Wire Digital Interface
Electrical Specifications
Figure 10. Line Transient Response for 4 LEDs at
VIN=3.6V ± 0.6V with L=10µH, COUT=1.0µF and
ILED=25mA
Figure 11. FAN5341 Dimming Operation at VIN=3.6V for 4
LEDs with L=10µH, COUT=1.0µF and ILED=25mA
Figure 13.Steady-State Waveform for VOUT, Switch Voltage
and Inductor Current for 4 LEDs at VIN=3.6V ±
0.6V with L=10µH, COUT=1.0µF and ILED=25mA
Figure 12. Startup Waveform for Switch Voltage, Inductor
Current, VFB and EN for 4 LEDs at VIN=3.6V±
0.6V with L=10µH, COUT=1.0µF and ILED=25mA
© 2009 Fairchild Semiconductor Corporation
FAN5341 • Rev. 1.0.1
www.fairchildsemi.com
7
FAN5341 — Series Boost LED Driver with Integrated Schottky Diode and Single-Wire Digital Interface
Electrical Specifications
FAN5341 does not require the system processor to
constantly supply a signal to it to drive the LEDs.
Overview
The FAN5341 is an inductive current-mode boost serial
LED driver that achieves LED current regulation by
maintaining 0.253V across the RSET resistor. The current
through the LED string (ILED) is therefore given by:
I LED =
0.253
RSET
Digital Dimming Control
The FAN5341 starts driving the LEDs at the maximum
brightness level. After startup, the control logic is ready to
accept programming pulses to decrease the brightness
level by the number of positive edges applied to the EN pin.
Figure 14 shows the digital pulse dimming control.
(1)
The voltage VOUT is determined by the sum of the forward
voltages across each LED, plus the voltage across RSET,
which is always 253mV.
Over-Current and Short-Circuit Detection
Driving Five LEDs in Series
Over-Voltage / Open-Circuit Protection
FAN5341 can drive five LEDs in series but, the forward
voltage (VF) of the LED MUST be less than 3.5V such that it
remains under the over-voltage specification of 18.9V.
If the LED string is an open circuit, FB remains at 0V and
the output voltag continues to increase in the absence of an
over-voltage protection (OVP) circuit. The FAN5341’s OVP
circuit disables the boost regulator when VOUT exceeds
18.9V and continues to keep the regulator off until VOUT
drops below 18.1V.
The boost regulator employs a cycle-by-cycle peak inductor
current limit of ~750mA.
UVLO and Soft-Start
If EN has been low for more than 1ms, the IC may initiate a
“cold start” soft-start cycle when EN rises, provided VIN is
above the UVLO threshold.
Thermal Shutdown
When the die temperature exceeds 150°C, a reset occurs
and remains in effect until the die cools to 125°C, at which
time, the circuit is allowed to begin the soft-start sequence.
Digital Interface
The FAN5341 implements a single-wire digital interface to
program the LED brightness to one of thirty-two (32) levels
spaced in linear steps. With this single-wire solution, the
Figure 14. Digital Pulse-Dimming Control Diagram
© 2009 Fairchild Semiconductor Corporation
FAN5341 • Rev. 1.0.1
www.fairchildsemi.com
8
FAN5341 — Series Boost LED Driver with Integrated Schottky Diode and Single-Wire Digital Interface
Circuit Description
Inductor & Output Capacitor Selection
# of LEDs
Inductor (L)
10.0µH
3, 4, 5
4.7µH
Part Number
Manufacturer
LQH43MN100K03
Murata
NLCV32T-100K-PFR
TDK
VLF3010AT-100MR49-1
TDK
LQH43MN4R7K03
Murata
NLCV32T-4R7M-PFR
TDK
LPF2010T-4R7M
ABCO
Min COUT
Part Number
Manufacturer
1.00µF
CV105X5R105K25AT
AVX/Kyocera
1.00µF
CV105X5R105K25AT
AVX/Kyocera
Table 1. Recommended External Components
Component Placement and PCB Recomendations
Figure 15. Recommended Component Placement
PCB Recommendations
Input Capacitance
In a typical application, the input and output capacitors
should be placed as close to the IC as possible; no
additional capacitance is needed to ensure proper
functionality. However, in a testing environment, where the
FAN5341 is typically powered by a power supply with
relatively long cables, an additional input capacitor (10µF)
may be needed to ensure stable functioning. This capacitor
should be placed close to where the power supply cables
attach to the FAN5341 evaluation board.
© 2009 Fairchild Semiconductor Corporation
FAN5341 • Rev. 1.0.1
ƒ The inductor can be connected to VIN with vias through
another layer if needed.
ƒ The feedback pin should be connected back to the IC on
a sub-layer.
www.fairchildsemi.com
9
FAN5341 — Series Boost LED Driver with Integrated Schottky Diode and Single-Wire Digital Interface
Application Information
0.10 C
A
2.0
2X
B
1.45
2.0
PIN1
IDENT
(0.25)
0.10 C
0.80 1.80
2X
6X 0.50
TOP VIEW
6X 0.35
0.55 MAX
0.65
A
0.10 C
RECOMMENDED LAND PATTERN
(0.15)
0.08 C
0.05
0.00
C
SEATING
PLANE
SIDE VIEW
NOTES:
A. PACKAGE CONFORMS TO JEDEC MO-229
EXCEPT WHERE NOTED.
1.35
1.45
PIN1
IDENT
1
3
B. DIMENSIONS ARE IN MILLIMETERS.
6X 0.35
0.25
0.10 C A B
0.05 C
C. DIMENSIONS AND TOLERANCES PER
ASME Y14.5M, 1994.
0.70
0.80
6
D. LANDPATTERN RECOMMENDATION IS BASED
ON FSC DESIGN ONLY.
E. DRAWING FILENAME: MKT-UMLP06Erev2.
4
0.65
0.35
6X 0.25
BOTTOM VIEW
Figure 16. 6-Lead Molded Leadless Package (UMLP)
Package drawings are provided as a service to customers considering Fairchild components. Drawings may change in any manner without
notice. Please note the revision and/or date on the drawing and contact a Fairchild Semiconductor representative to verify or obtain the most
recent revision. Package specifications do not expand the terms of Fairchild’s worldwide terms and conditions, specifically the warranty therein, which covers
Fairchild products.
Always visit Fairchild Semiconductor’s online packaging area for the most recent package drawings:
http://www.fairchildsemi.com/packaging/.
© 2009 Fairchild Semiconductor Corporation
FAN5341 • Rev. 1.0.1
www.fairchildsemi.com
10
FAN5341 — Series Boost LED Driver with Integrated Schottky Diode and Single-Wire Digital Interface
Physical Dimensions
FAN5341 — Series Boost LED Driver with Integrated Schottky Diode and Single-Wire Digital Interface
11
www.fairchildsemi.com
© 2009 Fairchild Semiconductor Corporation
FAN5341 • Rev. 1.0.1
ON Semiconductor and
are trademarks of Semiconductor Components Industries, LLC dba ON Semiconductor or its subsidiaries in the United States and/or other countries.
ON Semiconductor owns the rights to a number of patents, trademarks, copyrights, trade secrets, and other intellectual property. A listing of ON Semiconductor’s product/patent
coverage may be accessed at www.onsemi.com/site/pdf/Patent−Marking.pdf. ON Semiconductor reserves the right to make changes without further notice to any products herein.
ON Semiconductor makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does ON Semiconductor 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.
Buyer is responsible for its products and applications using ON Semiconductor products, including compliance with all laws, regulations and safety requirements or standards,
regardless of any support or applications information provided by ON Semiconductor. “Typical” parameters which may be provided in ON Semiconductor 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. ON Semiconductor does not convey any license under its patent rights nor the rights of others. ON Semiconductor products are not
designed, intended, or authorized for use as a critical component in life support systems or any FDA Class 3 medical devices or medical devices with a same or similar classification
in a foreign jurisdiction or any devices intended for implantation in the human body. Should Buyer purchase or use ON Semiconductor products for any such unintended or unauthorized
application, Buyer shall indemnify and hold ON Semiconductor 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 ON Semiconductor was negligent regarding the design or manufacture of the part. ON Semiconductor is an Equal Opportunity/Affirmative Action Employer. This
literature is subject to all applicable copyright laws and is not for resale in any manner.
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