AW3641E
Feb 2019 V1.3
Flash Current & Flash Timer Programmable
1A Flash LED Driver
FEATURES
GENERAL DESCRIPTION
8 Flash LED Current Levels Selectable
by 1-wire Interface:
The AW3641E is a current-regulated charge pump
ideal for powering high brightness LEDs for
camera flash applications. The charge pump can
be set to regulate two current levels for FLASH
and TORCH modes.
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Flash LED Current up to 1A Among Full
Power Supply Range
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100%*IFLASH, 90%*IFLASH……30%*IFLASH
PWM Dimming Control in Torch Mode
Automatic 1X/2X Mode Switchover
Up to 92% Efficiency in Torch Mode
Low 47mV Reference for Low Loss Sensing
Built-In Soft Start Limits Inrush Current
Over-Temperature Protection
Over-Voltage and Short-Circuit Protection
Low Ripple and EMI
Available in 3mm*3mm-10L DFN Package
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Ultra low RDSON: 0.4Ω(1X Mode), 2Ω(2X
Mode)
The AW3641E supports PWM dimming to adjust
the LED brightness during torch application by
simply providing a PWM signal to FLASH pin.
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The AW3641E incorporates a 1-wire interface to
program the flash LED current at 8 levels and flash
timeout at 2 levels.
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2 Flash Timeout Levels Selectable by
1-wire Interface: 220ms, 1.3s
The AW3641E features an ultra low RDSON, and
automatically switches modes between 1X and
2X, not only ensuring that LED current does not
depend on the forward voltage, but also optimizing
the efficiency at the whole power supply and load
range.
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APPLICATIONS
The AW3641E is available in a small 3mm*3mm
DFN-10L package and is specified over the -40℃
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Mobile Phones
PAD
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The AW3641E also features an automatic
soft-start mode to limit inrush current, as well as
over-temperature, over-voltage and short-circuit
protection.
to +85℃ ambient temperature range.
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TYPICAL APPLICATION CIRCUIT
VIN
1
CIN
10μF
2
CF
1μF
TORCH/FLASH
3
4
5
ENABLE
VIN
C1
PGND
C2
SGND
AW3641EDNR
FB
FLASH
VOUT
10
9
COUT
4.7μF
8
7
6
EN
Rdown
47kΩ
Figure 1
VOUT
RSET
EXPOSED PAD
11
RSET
86.6kΩ
RSENSE
0.22Ω
Typical Application Circuit of AW3641E
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Copyright © 2014~2015 SHANGHAI AWINIC TECHNOLOGY CO., LTD
AW3641E
Feb 2019 V1.3
PIN CONFIGURATION AND TOP MARK
AW3641EDNR MARKING
AW3641EDNR TOP VIEW
2
C2
3
FLASH 4
11
Exposed
Pad
8 SGND
7
EN 5
FB
6 RSET
3641E-AW3641EDNR
XXXX-Manufacture Date Code
Pin Configuration and Top Mark
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Figure 2
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DFN3x3-10L Package
PIN DEFINITION
NAME
1
VIN
Input voltage for the charge pump. Decouple with 10µF ceramic capacitor
(X5R/X7R) close to the pins of the IC.
2
C1
Positive input for the external flying capacitor. Connect a ceramic 1µF
capacitor (X5R/X7R) close to the pins of the IC.
3
C2
Negative input for the external flying capacitor. Connect a ceramic 1µF
capacitor (X5R/X7R) close to the pins of the IC.
FLASH
5
EN
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Logic input to toggle operation between FLASH and TORCH mode. In
Torch mode, FB is regulated to the internal 47mV reference. In Flash
mode, FB reference voltage can be adjusted by changing the resistor from
RSET pin to ground. Choose the external current sense resistor (R SENSE)
based on desired current in Torch mode and Flash mode
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DESCRIPTION
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No.
Shutdown control input. Connect to logic high for normal operation, and
logic low for shutdown. In FLASH mode, the flash current and timeout
period can be adjusted by EN 1-wire pulse control signal.
RSET
Connect a resistor from this pin to ground. When in FLASH mode (FLASH
= High), this resistor sets the current regulation point according to the
following equation:
VFB=(1.26V/RSET)×10.2kΩ
7
FB
Feedback input for the current control loop. Connect directly to the current
sense resistor: ILED=VFB/RSENSE
8
SGND
Internal ground pin. Control circuitry returns current to this pin.
9
PGND
Power ground pin. Flying capacitor current returns through this pin.
10
VOUT
Charge Pump Output Voltage. Decouple with an external X5R/X7R
capacitor. A 4.7µF capacitor is recommended.
11
Exposed Pad
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3641E
XXXX
9 PGND
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C1
10 VOUT
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VIN
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Exposed Pad must be soldered to the PCB board and connected to GND.
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Copyright © 2014~2015 SHANGHAI AWINIC TECHNOLOGY CO., LTD
AW3641E
Feb 2019 V1.3
FUNCTIONAL BLOCK DIAGRAM
AW3641E
VIN
1X/2X
CHARGE
PUMP
MODE
CONTROL
FLASH
+
SGND
-
FB
RSET
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RSET
BLOCK
Functional Block Diagram
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Figure 3
VRSET
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47mV
REFERENCE
1
0
VREF
EN
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OSC
&
TIMER
COMP
C2
PGND
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C1
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VOUT
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Copyright © 2014~2015 SHANGHAI AWINIC TECHNOLOGY CO., LTD
AW3641E
Feb 2019 V1.3
TYPICAL APPLICATION CIRCUITS
The typical application is shown Figure 4, where IFLASH=675mA，ITORCH=214mA.
2
CF
1μF
3
4
TORCH/FLASH
5
ENABLE
VOUT
C1
PGND
C2
SGND
AW3641EDNR
9
COUT
4.7μF
8
7
6
EN
RSET
Rdown
47kΩ
RSET
86.6kΩ
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EXPOSED PAD
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11
RSENSE
0.22Ω
Typical Application of 700mA Flash Current
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Figure 4
FB
FLASH
VOUT
10
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CIN
10μF
VIN
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VIN
VIN
CIN
10μF
2
3
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CF
1μF
TORCH/FLASH
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in
ENABLE
NOTE1:
VIN
C
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The typical application is shown Figure 5, where IFLASH=1.04A，ITORCH=214mA.
4
5
C1
PGND
C2
SGND
AW3641EDNR
FB
FLASH
VOUT
10
9
COUT
4.7μF
8
7
6
EN
RSET
Rdown
47kΩ
Figure 5
VOUT
EXPOSED PAD
11
RSET
56kΩ
RSENSE
0.22Ω
Typical Application of 1A(NOTE1) Flash Current
The exact flash current is 1.04A due to the typical value RSET=56kΩ and RSENSE=0.22Ω.
IFLASH=VFB / RSENSE=(1.26V/RSET )×10.2kΩ / RSENSE=1.04A.
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Copyright © 2014~2015 SHANGHAI AWINIC TECHNOLOGY CO., LTD
AW3641E
Feb 2019 V1.3
The AW3641E also can be used to drive two flash LEDs in portable equipment, the schematic is shown in
Figure 6. In this application, IFLASH_D1=IFLASH_D2=488mA, ITORCH_D1=ITORCH_D2=100mA.
TORCH/FLASH
3
4
5
ENABLE
C1
PGND
C2
SGND
AW3641EDNR
COUT
4.7μF
D1
500mA LED
8
R1
10kΩ
FB
FLASH
9
R2
10kΩ
7
6
EN
RSET
Rdown
47kΩ
RSET
56kΩ
EXPOSED PAD
11
Figure 6
RSENSE
0.47Ω
D2
500mA LED
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CF
1μF
VOUT
10
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2
VOUT
RSENSE
0.47Ω
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CIN
10μF
VIN
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Two Flash LEDs Application
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VIN
Notice for Typical Application Circuits:
CIN, CF, COUT, RSET, RSENSE close to the pins of the IC, and the ground terminal of RSENSE close to the SGND/PGND
pins of the IC.
2.
Red line is high current path. Consider driving ability, for example ，IOUT=700mA，the power path
VOUT--LED--RSENSE--GND should be as short and wide as possible, at least 30mil trace is recommended
(IOUT=700mA).The power path between Battery and VIN, at least 60mil trace is recommended (IIN=1.4A@2X Mode).
3.
For better thermal performance and noise performance, the Exposed Pad, PGND pin and SGND pin should be
connected directly to a large area of the PCB ground plane.
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1.
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Copyright © 2014~2015 SHANGHAI AWINIC TECHNOLOGY CO., LTD
AW3641E
Feb 2019 V1.3
ORDERING INFORMATION
Part Number
Temperature
Package
Marking
Delivery Form
AW3641EDNR
-40℃～85℃
DFN 3mm*3mm-10L
3641E
6000 units/
Tape and Reel
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AW3641E
Shipping
R: Tape & Reel
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Package Type
DN: DFN
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ABSOLUTE MAXIMUM RATINGS(NOTE2)
PARAMETERS
RANGE
-0.3V to 6V
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Voltage at VIN,VOUT
−0.3V to the lesser of (VIN+0.3V) w/ 6V max
Voltage at EN, FLASH
Output Current Pulse(Flash)
Junction to Ambient Thermal Resistance θJA
Max Junction Temperature TJMAX
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Storage Temperature TSTG
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Ambient Temperature
Lead Soldering Temperature, 10 Seconds
ESD, All Pins(NOTE3)
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Output Current Continuous(Torch)
0.4A
57℃/W
-40℃ to 85℃
150℃
-65℃ to 150℃
260℃
8000V
CDM
MM
2000V
350V
in
Latch-up
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HBM
1.2A
+IT：+450mA
JEDEC STANDARD NO.78B DECEMBER 2008
-IT：-450mA
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Testing Standard：
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NOTE2: Stresses beyond those listed under absolute maximum ratings may 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 under recommended operating conditions is not implied. Exposure to absolute-maximum-rated conditions for
extended periods my affect device reliability.
NOTE3: The human body model is a 100-pF capacitor discharged through a 1.5kΩ resistor into each pin. The machine
model is a 200-pF capacitor discharged directly into each pin. Testing standard：MIL-STD-883G Method 3015.7.
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Copyright © 2014~2015 SHANGHAI AWINIC TECHNOLOGY CO., LTD
AW3641E
Feb 2019 V1.3
ELECTRICAL CHARACTERISTICS
Test Condition: TA = 25℃, VIN = 3.6V, EN = VIN, FLASH =VIN (Unless otherwise specified)
PARAMETER
TEST CONDITION
MIN
TYP
MAX
UNIT
5.5
V
1
μA
IQ
Quiescent Current
EN=0V
0.1
FLASH=0V，ILOAD=100uA
0.4
FLASH=VIN，2X Mode
FOSC
Oscillator Frequency
RDSON_2X
Charge Pump Equivalent
Resistance (2X mode)
RDSON_1X
Charge Pump Equivalent
Resistance (1X mode)
VFB
FB Reference Voltage
1.4
FLASH=VIN, RSET=86.6kΩ
EN, FLASH Logic High
VIL
EN, FLASH Logic Low
IEN
EN, FLASH Pin Current
TON
VOUT Turn-on Time
VFB=0.3V
160
42
47
52
C
Thermal Shutdown
Temperature
MHz
Ω
Ω
mV
1
μA
V
0.4
VIN = 3.6V, FB within 90%
of regulation
Flash Timeout Period
V
5
μA
500
μs
1-wire pulse rising edge
number: 1~8
180
220
310
ms
1-wire pulse rising edge
number: 9~16
1.05
1.3
1.85
s
147
℃
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TSD
150
1.3
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TFLASH
2.4
137
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VIH
mA
0.4
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FB Pin Current
1.9
mA
2
FLASH=GND
IFB
6
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Shutdown Current
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ISD
2.8
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Input voltage range
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VIN
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SUPPLY VOLTAGE AND CURRENT
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Copyright © 2014~2015 SHANGHAI AWINIC TECHNOLOGY CO., LTD
AW3641E
Feb 2019 V1.3
TYPICAL CHARACTERISTICS
Test Condition: CIN=10μF, COUT=4.7μF, CF=1μF (Unless otherwise specified)
Soft Start
Soft Start
VIN=4.2V, 1X Mode, Flash, IOUT=500mA
VIN=3.6V, 2X Mode, Flash, IOUT=500mA
VEN
5V/div
VOUT
2V/div
VOUT
2V/div
IIN
0.5A/div
IIN
0.5A/div
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Time(200μs/div)
Soft Start
VIN=4.2V, 1X Mode, Flash, IOUT=700mA
Soft Start
VIN=3.6V, 2X Mode, Flash, IOUT=700mA
VEN
5V/div
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VEN
5V/div
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VOUT
2V/div
IIN
0.5A/div
VOUT
2V/div
IOUT
0.5A/div
Time(200μs/div)
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Time(200μs/div)
Soft Start
Soft Start
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VIN=3.4V, 2X Mode, Flash, IOUT=1A
VIN=4.2V, 2X Mode, Flash, IOUT=1A
VEN
5V/div
VEN
5V/div
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Time(200μs/div)
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VEN
5V/div
VOUT
2V/div
VOUT
2V/div
IIN
1A/div
IIN
1A/div
Time(200μs/div)
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Time(200μs/div)
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Copyright © 2014~2015 SHANGHAI AWINIC TECHNOLOGY CO., LTD
AW3641E
Feb 2019 V1.3
Test Condition: CIN=10μF, COUT=4.7μF, CF=1μF (Unless otherwise specified)
Soft Start
Soft Start
VIN=3.6V, 1X Mode, Torch, IOUT=140mA
VIN=3.6V, 1X Mode,Torch, IOUT=214mA
VEN
5V/div
VOUT
1V/div
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VEN
5V/div
VOUT
1V/div
IIN
0.2A/div
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IIN
0.2A/div
Time(200μs/div)
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Time(200μs/div)
Flash time 220ms
Flash time 1.3s
VIN=4.2V, IFLASH=1A
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VIN=4.2V, IFLASH=1A
VOUT
5V/div
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VOUT
5V/div
VFLASH
2V/div
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VFLASH
2V/div
ILED
1A/div
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ILED
500mA/div
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Time(50ms/div)
Time(200ms/div)
PWM Dimming for Torch Current
Flash Current Setting by 1-Wire Interface
in
VIN=4.2V, IFLASH=1A (Pulse=1)
VIN=4.2V, IFLASH=1A, ITORCH=0.1A, Duty=20%
PWM
5V/div
100%*IF LASH
VOUT
2V/div
90%*IF LASH
80%*IF LASH
70%*IF LASH
60%*IF LASH
50%*IF LASH
40%*IF LASH
30%*IF LASH
Pulse= 1
2
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IFLASH
250mA/div
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3
4
5
6
7
8
VFB
200mV/div
ILED
200mA/div
Time(50 μs/div)
Time(200ms/div)
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Copyright © 2014~2015 SHANGHAI AWINIC TECHNOLOGY CO., LTD
AW3641E
Feb 2019 V1.3
Test Condition: CIN=10μF, COUT=4.7μF, CF=1μF (Unless otherwise specified)
Torch 1X to Flash 1X
Torch 1X to Flash 2X
VOUT
2V/div
VOUT
2V/div
VFB
200mV/div
VFB
100mV/div
ILED
1A/div
ILED
500mA/div
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VFLASH
5V/div
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VIN=3.6V, IFLASH=1A, ITORCH=214mA
VFLASH
5V/div
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VIN=4.2V, IFLASH=500mA, ITORCH=214mA
Time(50ms/div)
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Time(50ms/div)
Output Ripple
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Output Ripple
VIN=4.2V, 1X Mode, Flash, ILED=500mA
VIN=4.2V, 1X Mode, Torch, ILED=214mA
VIN
AC coupled
20mV/div
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VIN
AC coupled
20mV/div
VOUT
AC coupled
20mV/div
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VOUT
AC coupled
20mV/div
Time(1μs/div)
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Time(1μs/div)
Output Ripple
Output Ripple
VIN=3.6V, 2X Mode, Flash, ILED=500mA
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VIN=3.6V, 2X Mode, Flash, ILED=1A
VIN
AC coupled
100mV/div
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VIN
AC coupled
100mV/div
VOUT
AC coupled
100mV/div
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VOUT
AC coupled
100mV/div
Time(1μs/div)
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Time(1μs/div)
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Copyright © 2014~2015 SHANGHAI AWINIC TECHNOLOGY CO., LTD
AW3641E
Feb 2019 V1.3
Test Condition: CIN=10μF, COUT=4.7μF, CF=1μF (Unless otherwise specified)
Battery Current vs. Input Voltage
Output Current vs. Input Voltage
1200
2400
(6)
(4)
400
(3)
(2)
(5)
1200
(4)
800
(1)
(1)
0
3.0
3.2
3.4
3.6
3.8
4.0
0
4.4
4.2
Input Voltage(V)
3.0
3.2
3.6
3.4
3.8
4.0
4.2
4.4
Input Voltage(V)
(2) Torch 200mA, VF=3.12V
(1) Torch 100mA, VF=2.93V
(2) Torch 200mA, VF=3.12V
(3) Flash 300mA, VF=3.19V
(4) Flash 500mA, VF=3.46V
(3) Flash 300mA, VF=3.19V
(4) Flash 500mA, VF=3.46V
(5) Flash 700mA, VF=3.62V
(6) Flash 1000mA, VF=3.98V
(5) Flash 700mA, VF=3.62V
(6) Flash 1000mA, VF=3.98V
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(1) Torch 100mA, VF=2.93V
Efficiency vs. Input Voltage
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100
(1)
80
(3)
(4)
60
(5)
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(2)
(6)
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EFficiency(%)
(3)
(2)
400
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200
1600
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(5)
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Battery Current(mA)
Output Current(mA)
800
600
(6)
2000
1000
40
0
3.0
3.2
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20
3.4
3.6
3.8
4.0
4.2
4.4
Input Voltage(V)
in
(1) Torch 100mA, VF=2.93V
(2) Torch 200mA, VF=3.12V
(4) Flash 500mA, VF=3.46V
(5) Flash 700mA, VF=3.62V
(6) Flash 1000mA, VF=3.98V
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(3) Flash 300mA, VF=3.19V
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Copyright © 2014~2015 SHANGHAI AWINIC TECHNOLOGY CO., LTD
AW3641E
Feb 2019 V1.3
DETAILED FUNCTIONAL DESCRIPTION
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The AW3641E is a charge pump regulator designed to drive white LEDs supplied by a Li-Ion battery of 2.8V
to 4.4V for digital still camera Flash and Torch applications. The AW3641E is pin selectable to operate in
either Flash or Torch mode. Flash mode is usually with a pulse of about 200 to 300 milliseconds to generate a
high intensity Flash. Torch can be used continuously at a lower output current than Flash and is often used for
several seconds in a digital still camera “movie” mode.
Adaptive Charge Pump
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The AW3641E also has two operating modes to control the output current: the 1X mode and 2X mode. After
50μs’ delay of the enable pin EN receiving logic high, the Bandgap reference wakes up. Then AW3641E goes
through a soft-start mode designed to limit inrush current. The AW3641E starts in the 1X mode firstly, which
acts like a linear regulator to control the output current by continuously monitoring the feedback pin FB. In 1X
mode, if the FB pin is below the reference voltage for more than 8μs, the AW3641E will automatically switch
to 2X mode. In 2X mode, if the working condition satisfy VIN > VOUT + IOUT*RDSON_1X + ΔV for more than 32μs, it
will switch back to 1X mode, otherwise stay in 2X mode. Wherein ΔV is a fixed hysteresis voltage, RDSON_1X is
the equivalent resistance in 1X mode.
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Flash Mode
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Flash mode is activated by pulling the EN and FLASH pin high. And the feedback regulation voltage VFB,
which is set by the resistor RSET connected between the RSET pin and SGND pin, equals to
VFB = (1.26V/RSET)*10.2kΩ (Flash mode)
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Where 1.26V is the internal Bandgap reference voltage and 10.2kΩ is an internal resistance used to scale the
RSET current. Typically, RSET ranges from 42kΩ to 170kΩ, with VFB corresponding from 306mV to 76mV. Then,
the output current IOUT can be calculated for both Flash and Torch modes by the equation:
IOUT = VFB / RSENSE
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For example , in Figure 4, RSENSE=0.22Ω，RSET=86.6kΩ，it’s obtained:
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VFB = (1.26V/86.6kΩ)*10.2kΩ = 148.4mV
IFLASH = 148.4mV/0.22Ω = 675mA
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Once the RSENSE and RSET is selected, the AW3641E provides 8 flash LED current levels from 100%* IFLASH to
30%* IFLASH in 10%* IFLASH steps by 1-wire interface in the EN pin.
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Torch Mode
Setting the EN pin to logic high and the FLASH pin to logic low, the AW3641E will enter Torch mode. The
feedback voltage VFB is regulated to be 47mV, which can’t be adjusted by external components.
VFB = 47mV (Torch Mode)
For example , in Figure 4, RSENSE=0.22Ω，it’s obtained:
ITORCH = 47mV/0.22Ω = 214mA
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Copyright © 2014~2015 SHANGHAI AWINIC TECHNOLOGY CO., LTD
AW3641E
Feb 2019 V1.3
Flash Timeout Protection
The duration of a single flash is limited automatically to TTIMEOUT, which applies only for Flash mode. This
protects the flash LED against thermal damage.
The AW3641E also provides 2 flash timeout levels (220ms/1.3s) by 1-wire interface in the EN pin.
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1-wire Interface
The AW3641E incorporates a 1-wire interface to program the flash LED current at 8 levels and flash timeout
at 2 levels.
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The relationship between the number of 1-wire pulse rising edge and flash LED current & flash timeout is
shown in Table 1.
Flash Timeout
EN Waveform
(TTIMEOUT)
1
2
3
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4
90%*IFLASH
80%*IFLASH
70%*IFLASH
220ms
6
............
7
............
8
............
30%*IFLASH
9
............
100%*IFLASH
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............
50%*IFLASH
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40%*IFLASH
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60%*IFLASH
............
90%*IFLASH
............
80%*IFLASH
in
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100%*IFLASH
5
10
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Flash LED Current
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Pulse
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Table 1 flash LED current & flash timeout adjusting by 1-wire interface
............
70%*IFLASH
1.3s
13
............
14
............
50%*IFLASH
15
............
40%*IFLASH
16
............
30%*IFLASH
60%*IFLASH
The 1-wire pulse timing sequence is shown in Figure 7. The duration of logic high (T HI) and logic low (TLO) is
recommended between 0.75us to 10us. And shutdown duration TOFF should be longer than 500us.
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Copyright © 2014~2015 SHANGHAI AWINIC TECHNOLOGY CO., LTD
AW3641E
Feb 2019 V1.3
0.75μs≤THI≤10μs
EN
1
TOFF≥500μs
2
3
SHUTDOWN
NORMAL STATE
Figure 7
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0.75μs≤TLO≤10μs
1-wire pulse timing sequence（take 80%*IFLASH/220ms for example）
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Flash Current & RDSON
VIN - IOUT*RDSON_1X = VOUT
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The maximum drive capacity in 2X mode is:
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For 1X/2X mode charge pump flash LED driver, the maximum drive capacity in 1X mode is:
2*VIN - IOUT*RDSON_2X = VOUT
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The output voltage VOUT depends on the flash LED forward voltage VF. However, VF is widely dispersed. For
example, for 1A flash LED, VF varies from minimum 2.95V to maximum 4.35V, whose deviation
reaches1.4V. Assuming such condition: the LED driver supplied by a battery with voltage VIN = 3.6V，and
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driving a flash LED with VF=4.35V. It’s estimated that VOUT=VF+VFB≈4.5V. According to the formula of 2X
mode charge pump, the equivalent resistance on 2X mode must satisfy:
RDSON_2X < (2*VIN - VOUT) / IOUT=(2*3.6V - 4.5V)/1A = 2.7Ω.
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That means driving the 1A flash LED with VF = 4.35V, RDSON_2X should not exceed 2.7Ω. The equivalent
resistance of AW3641E in is 2X mode RDSON_2X = 2Ω, equivalent resistance in 1X mode is RDSON_1X = 0.35Ω,
ensuring 1A output current in the whole battery voltage range, even for the worst VF.
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When VF < VIN - IOUT*RDSON_1X = 3.6V - 1A*0.35Ω = 3.25V, the AW3641E can work in 1X mode, with higher
overall efficiency.
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PWM Dimming
ITORCH_PWM = IFLASH*D + ITORCH*(1-D)
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The AW3641E supports PWM dimming to adjust the LED brightness during Torch application by simply
providing a PWM signal to FLASH pin. In this condition, the AW3641E switches between FLASH mode and
TORCH mode. For AW3641E, the dimming frequency is recommended between 20kHz to 50kHz. The
relationship between the output current IOUT and the duty cycle of PWM signal D is written as below:
In which IFLASH is output current setting for FLASH mode and ITORCH is output current setting for TORCH mode.
For example, if ITORCH = 100mA, IFLASH = 700mA and D=20%, the output current increases to:
ITORCH_PWM＝700mA*20% + 100mA*(1-20%)=220mA(NOTE4)
The PWM dimming sequence is shown in Figure 8. Firstly, setting the EN pin to logic high and the FLASH pin
to logic low, the AW3641E will enter Torch mode. After a delay of TDELAY, PWM signal may be applied to the
Flash pin, where the TDELAY must be longer than 2ms.
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Copyright © 2014~2015 SHANGHAI AWINIC TECHNOLOGY CO., LTD
AW3641E
Feb 2019 V1.3
EN
TDELAY≥2ms
PWM Dimming signal
FLASH
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PWM dimming sequence
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Figure 8
NOTE4: The ITORCH_PWM must be less than the LED DC Forward Current which is described in the LED datasheet, and
usually Don’t exceed 350mA.
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Over-Voltage Protection (OVP)
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The AW3641E provides over-voltage protection. If the output voltage rises above the threshold of 5.5V, the
over voltage protection shuts down all the output switches, to prevent the output voltage from rising further.
After that, when the output voltage drops below 5.3V, the device resumes normal operation.
Over-Temperature Protection
When the temperature of the AW3641E rises above 135℃, the AW3641E begins to reduce the output current,
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and when the temperature rises above 147℃, the over-temperature protection circuitry turns off the output
Short-Circuit Protection
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switches to prevent damage to the device. If the temperature drops back down below 125℃, the device
automatically recovers and executes a soft start cycle.
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When the VOUT pin is shorted to GND, which makes the VOUT falls below to 1V, the device stops switching
and operates as a current source limiting the output current to 70mA.
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Copyright © 2014~2015 SHANGHAI AWINIC TECHNOLOGY CO., LTD
AW3641E
Feb 2019 V1.3
APPLICATION INFORMATION
Capacitor Selection
The AW3641E requires three capacitors. The recommended value: Input Capacitance CIN = 10μF,
capacitor COUT = 4.7μF, flying capacitor CF = 1μF.
output
Table 2 Recommended Capacitor Value and Size
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Use low-ESR ceramic capacitors with X7R or X5R dielectric. These capacitors allow good filtering and have a
wide temperature range. The connections of all external capacitors should be kept as short as possible.
Value
Withstanding Voltage
Size
Vendor
CIN
10μF
6.3V
0603
EYANG or Murata
COUT
4.7μF
6.3V
0402
EYANG or Murata
CF
1μF
5V
0402
EYANG or Murata
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Part
Resistor Selection/Current Setting
Step1: Select RSENSE
The sense resistor RSENSE is determined by the desired output current in Torch mode by the equation:
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RSENSE = VFB_TORCH / ITORCH
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Where VFB_TROCH = 47mV (Torch Mode)
Step2: Calculate VFB
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Once the RSENSE resistor has been selected for Torch mode, the feedback voltage in Flash mode VFB_FLASH
obtained using the following equation:
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VFB_FLASH = IFLASH*RSENSE (Flash Mode)
Step3: Select RSET
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Where IFLASH is the flash LED current.
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RSET resistor can be selected for Flash mode using the following equation:
RSET = (1.26V/VFB_FLASH)*10.2kΩ
(Flash Mode)
For an example of 200mA Torch mode and 800mA Flash mode:
the values RSENSE = 47mV/200mA = 0.235Ω;
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1)
VFB = 800mA×0.235Ω = 188mV (Flash Mode);
3)
RSET = (1.26V/188mV)×10.2kΩ = 68.4kΩ are calculated;
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The power consumption on RSENSE in the Flash mode would be:
PRSENSE_FLASH = VFB_FLASH*IFLASH = 188mV*800mA = 150mW.
The normal 0603 surface mount resistor is rated as 0.1 Watt for continuous power and 0.2 Watt for pulsed
power, and the normal 0805 surface mount resistor is rated as 0.125 Watt for continuous power and 0.25 Watt
for pulsed power, the power 0805 surface mount resistor is rated as 0.25 Watt for continuous power and 0.5
Watt for pulsed power. The PRSENSE_FLASH power can be calculated and resistor size selected accordingly.
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AW3641E
Feb 2019 V1.3
Considering the power deviation, it is strongly recommended to use the power 0805 surface mount resistor.
Referring to the following Table 3 to choose RSENSE size.
Resistance
Tolerance(+/-)
IFLASH(A)
PRSENSE(W)
Type
Size
RSENSE
0.22Ω
1%
0.5
0.055
Normal
0603
RSENSE
0.22Ω
1%
0.7
0.108
Normal
0805
RSENSE
0.22Ω
1%
1.0
0.22
Power
0805
RSENSE
0.33Ω
1%
0.5
0.083
Normal
RSENSE
0.33Ω
1%
0.7
0.16
Power
RSENSE
0.47Ω
1%
0.5
0.12
Normal
RSENSE
0.47Ω
1%
0.7
0.23
Power
0805
0805
0805
0805
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Table 3 Typical RSENSE Resistor Value and Size
The range of normal RSET resistor values and sizes are shown here in Table 4.
Resistance
Tolerance(+/-)
RSET
56kΩ
1%
RSET
61kΩ
1%
RSET
68kΩ
1%
RSET
75kΩ
1%
RSET
82kΩ
1%
RSET
91kΩ
RSET
100kΩ
RSET
0402
EYANG or Murata
0402
EYANG or Murata
0402
EYANG or Murata
0402
EYANG or Murata
0402
EYANG or Murata
1%
0402
EYANG or Murata
1%
0402
EYANG or Murata
110kΩ
1%
0402
EYANG or Murata
120kΩ
1%
0402
EYANG or Murata
130kΩ
1%
0402
EYANG or Murata
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RSET
Vendor
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RSET
Size
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Table 4 RSET Resistor Value and Size
140kΩ
1%
0402
EYANG or Murata
RSET
150kΩ
1%
0402
EYANG or Murata
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RSET
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Copyright © 2014~2015 SHANGHAI AWINIC TECHNOLOGY CO., LTD
AW3641E
Feb 2019 V1.3
PCB LAYOUT CONSIDERATION
To achieve adequate electrical and thermal performance, careful attention must be paid to the PCB layout. In
the worst-case operating condition, the chip must dissipate considerable power at full load. Adequate
heat-sinking must be achieved to ensure intended operation.
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1. The flying capacitor CF should be connected close to the chip. Trace length should be kept short to
minimize path resistance and potential coupling. The input and output capacitors should also be placed
as close to the chip as possible.
2. Keep the IC far from FM, RF and PA modules to avoid EMI interference.
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3. The bottom of the package features an exposed metal paddle. The exposed paddle acts, thermally, to
transfer heat from the chip and, electrically, as a ground connection.
AW3641E PCB Layout Consideration
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Figure 9
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Copyright © 2014~2015 SHANGHAI AWINIC TECHNOLOGY CO., LTD
AW3641E
Feb 2019 V1.3
TAPE AND REEL INFORMATION
Carrier Tape
Φ 1.5 +0.1/-0.0
8.00
Φ 1.50 MIN
2.00 ±.05 SEE NOTE3
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1.75 ±.10
4.00 SEE NOTE1
0.30 ±.05
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5.50 ±.05
SEE NOTE 3
R 0.3 MAX
B0
12.0 ±.3
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A
K0
R.25
Unit: mm
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SECTION A - A
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0.25
A0
NOTES:
1. 10 SPROCKET HOLE CLIMULATIVE TOLERANCE ±0.2
2. CAMBER IN CMPLIANCE WITH EIA 481
3. POCKET POSITION RELATIVE TO SPROCKET HOLE MEASURED
AS TRUE POSITION OF POCKET, NOT OCKET HOLE
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A0 = 3.30
B0 = 3.30
K0 = 1.10
Pin 1 direction
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Pin 1
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AW3641E
Feb 2019 V1.3
Reel
R1 REF
Φ 330±2
R159 REF
0.5
2.4±0.3
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SEE DETAIL C
R121 REF
R127 REF
30o
30o
30o
R6 TYP
R48.00
R50.00
30o
R55 REF
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30o
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TX12 - 04 – EC1
6 TYP
+2.0
12.4 -0
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NOTES:
UNLESS OTHERWISE SPECIFIED
1. MATERIAL: DISSIPATIVE (BLACK)
2. FLANGE WARPAGE: 3 MM MAXIMUM
3. ALL DIMENSIONS ARE IN MM
4. ESD – SURFACE RESISTIVITY
– 105 TO 1011 OHMS/SQ
5. GENERAL TOLERANCE: –X.X=±0.4 , –X.XX=±0.20
6. TOTAL THICKNESS OF REEL: 18.4 MAX
7. PART NO: TX12–04-EC1
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SEE DETAIL C
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Copyright © 2014~2015 SHANGHAI AWINIC TECHNOLOGY CO., LTD
AW3641E
Feb 2019 V1.3
PACKAGE DESCRIPTION
0.250±0.050
3.000±0.100
0.500±0.100
1.650±0.100
Exp.DAP
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3.000±0.100
PIN #1 IDENTIFICATION
R 0.200 Ref
0.275±0.100
LASER MARK
PIN 1 I.D.
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2.400±0.100
Exp.DAP
Top View
MAX
A
NOM
MIN
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Bottom View
DFN
0.800
A
0.750
0.700
0.000~0.050
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unit : mm
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0.400±0.050
10L DFN
(3×3 mm)
0.200 Ref.
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Side View
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Copyright © 2014~2015 SHANGHAI AWINIC TECHNOLOGY CO., LTD
AW3641E
Feb 2019 V1.3
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Package Reflow Oven Thermal Profile
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Figure 22
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REFLOW
spec
Average ramp-up rate (217℃ to Peak)
Max. 3℃/sec
Time of Preheat temp.(from 150℃ to 200℃)
60-120sec
Time to be maintained above 217℃
60-150sec
Peak Temperature
>260℃
Time within 5℃ of actual peak temp
20-40sec.
Ramp-down rate
Max. 6℃/sec
Time from 25℃ to peak temp
Max. 8min.
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Reflow Note
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Copyright © 2014~2015 SHANGHAI AWINIC TECHNOLOGY CO., LTD
AW3641E
Feb 2019 V1.3
REVISION HISTORY
Vision
Date
Change Record
V0.9
Mar 2014
AW3641EDNR Datasheet Preliminary
V1.0
Oct 2014
AW3641EDNR Datasheet Released
V1.1
Feb 2015
Add PWM dimming sequence description
V1.2
Aug 2015
Add recommended land pattern (Page21)
V1.3
Mar 2019
Modify diagrams in typical characteristics (Page9-10)
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(Page14-15)
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23
Copyright © 2014~2015 SHANGHAI AWINIC TECHNOLOGY CO., LTD
AW3641E
Feb 2019 V1.3
DISCLAIMER
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Information in this document is believed to be accurate and reliable. However, Shanghai AWINIC Technology
Co., Ltd (AWINIC Technology) does not give any representations or warranties, expressed or implied, as to
the accuracy or completeness of such information and shall have no liability for the consequences of use of
such information.
AWINIC Technology reserves the right to make changes to information published in this document, including
without limitation specifications and product descriptions, at any time and without notice. Customers shall
obtain the latest relevant information before placing orders and shall verify that such information is current and
complete. This document supersedes and replaces all information supplied prior to the publication hereof.
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AWINIC Technology products are not designed, authorized or warranted to be suitable for use in medical,
military, aircraft, space or life support equipment, nor in applications where failure or malfunction of an
AWINIC Technology product can reasonably be expected to result in personal injury, death or severe property
or environmental damage. AWINIC Technology accepts no liability for inclusion and/or use of AWINIC
Technology products in such equipment or applications and therefore such inclusion and/or use is at the
customer’s own risk.
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Applications that are described herein for any of these products are for illustrative purposes only. AWINIC
Technology makes no representation or warranty that such applications will be suitable for the specified use
without further testing or modification.
All products are sold subject to the general terms and conditions of commercial sale supplied at the time of
order acknowledgement.
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Nothing in this document may be interpreted or construed as an offer to sell products that is open for
acceptance or the grant, conveyance or implication of any license under any copyrights, patents or other
industrial or intellectual property rights.
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Reproduction of AWINIC information in AWINIC data books or data sheets is permissible only if reproduction
is without alteration and is accompanied by all associated warranties, conditions, limitations, and notices.
AWINIC is not responsible or liable for such altered documentation. Information of third parties may be subject
to additional restrictions.
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Resale of AWINIC components or services with statements different from or beyond the parameters stated by
AWINIC for that component or service voids all express and any implied warranties for the associated
AWINIC component or service and is an unfair and deceptive business practice. AWINIC is not responsible or
liable for any such statements.
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