1.5 A LED Flash Driver with
I2C-Compatible Interface
ADP1650
FEATURES
APPLICATIONS
Camera-enabled cellular phones and smart phones
Digital still cameras, camcorders, and PDAs
FUNCTIONAL BLOCK DIAGRAM
INPUT VOLTAGE = 2.7V TO 5.0V
10µF
1.0µH
TX1/TORCH
VIN
GPIO1
SW
VOUT
TX2/ILED/ADC
GPIO2
10µF
ADP1650
STROBE
LED_OUT
MAX 1.5A
SCL
SGND
PGND
08837-001
SDA
EN
Figure 1.
Li-ION +
C1
L1
PGND
Li-ION +
C2
INDUCTOR
DIGITAL
INPUT/
OUTPUT
AREA = 16.4mm 2
LED
ANODE
08837-002
Ultracompact solution
Small, 2 mm × 1.5 mm, 12-ball WLCSP package
Thin, 3 mm × 3 mm × 0.75 mm, 10-lead LFCSP package
Smallest footprint, 1 mm height, 1 μH power inductor
LED current source for local LED grounding
Simplified routing to/from LED
Improved LED thermals
Synchronous 3 MHz PWM boost converter, no external diode
High efficiency: 90% peak
Reduces high levels of input battery current during flash
Limits battery current drain in torch mode
I2C programmable
Currents up to 1500 mA in flash mode for 1 LED with
±7% accuracy over all conditions
Currents up to 200 mA in torch mode
Programmable dc battery current limit (4 settings)
Programmable flash timer up to 1600 ms
Low VBAT mode to reduce LED current automatically
4-bit ADC for LED VF, die/LED temperature readback
Control
I2C-compatible control registers
External STROBE and torch input pins
2 transmitter mask (TxMASK) inputs
Safety
Thermal overload protection
Inductor fault detection
LED short-/open-circuit protection
Figure 2. PCB Layout (WLCSP)
GENERAL DESCRIPTION
The ADP1650 is a very compact, highly efficient, single white
LED flash driver for high resolution camera phones that
improves picture and video quality in low light environments.
The device integrates a programmable 1.5 MHz or 3 MHz
synchronous inductive boost converter, an I2C-compatible
interface, and a 1500 mA current source. The high switching
frequency enables the use of a tiny, 1 mm high, low cost, 1 μH
power inductor, and the current source permits LED cathode
grounding for thermally enhanced, low EMI, and compact
layouts.
The LED driver maximizes efficiency over the entire battery
voltage range to maximize the input-power-to-LED-power
conversion and to minimize battery current draw during flash
events. A programmable dc battery current limit safely maximizes
LED current for all LED VF and battery voltage conditions.
Two independent TxMASK inputs permit the flash LED current
and battery current to reduce quickly during a power amplifier
current burst. The I2C-compatible interface enables the programmability of timers, currents, and status bit readback for
operation monitoring and safety control.
The ADP1650 is available in a compact 12-ball, 0.5 mm pitch
WLCSP package and a 10-lead LFCSP package, and operates
within specification over the full −40°C to +125°C junction
temperature range.
Rev. C
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responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
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Fax: 781.461.3113 ©2010–2011 Analog Devices, Inc. All rights reserved.
ADP1650
TABLE OF CONTENTS
Features .............................................................................................. 1
Indicator LED Driver................................................................. 14
Applications....................................................................................... 1
Low Battery LED Current Foldback ........................................ 14
Functional Block Diagram .............................................................. 1
Programmable Battery DC Current Limit.............................. 15
General Description ......................................................................... 1
Analog-to-Digital Converter Operation ................................. 15
Revision History ............................................................................... 2
5 V Output Operation ............................................................... 16
Specifications..................................................................................... 3
Safety Features................................................................................. 18
Recommended Specifications: Input and Output Capacitance
and Inductance ............................................................................. 5
Short-Circuit Fault ..................................................................... 18
I2C-Compatible Interface Timing Specifications ..................... 5
Dynamic Overvoltage Mode (DOVP) .................................... 18
Absolute Maximum Ratings............................................................ 6
Timeout Fault.............................................................................. 18
Thermal Data ................................................................................ 6
Overtemperature Fault .............................................................. 18
Thermal Resistance ...................................................................... 6
Indicator LED Fault ................................................................... 18
ESD Caution.................................................................................. 6
Current Limit.............................................................................. 18
Pin Configurations and Function Descriptions ........................... 7
Input Undervoltage .................................................................... 18
Typical Performance Characteristics ............................................. 8
Soft Start ...................................................................................... 18
Theory of Operation ...................................................................... 12
Reset Using the Enable (EN) Pin ............................................. 18
White LED Driver ...................................................................... 12
Clearing Faults ............................................................................ 18
Modes of Operation ................................................................... 12
I2C Interface ................................................................................ 19
Assist Light .................................................................................. 13
I2C Register Map............................................................................. 20
Flash Mode .................................................................................. 13
Applications Information .............................................................. 26
Assist-to-Flash Operation ......................................................... 13
External Component Selection ................................................ 26
Torch Mode ................................................................................. 13
PCB Layout...................................................................................... 28
Torch-to-Flash Mode ................................................................. 14
Outline Dimensions ....................................................................... 29
TxMASK Operation................................................................... 14
Ordering Guide .......................................................................... 29
Overvoltage Fault ....................................................................... 18
Frequency Foldback ................................................................... 14
REVISION HISTORY
4/11—Rev. B to Rev. C
Added 10-Lead LFCSP Package........................................Universal
Changes to Features Section, General Description Section, and
Figure 2 Caption ............................................................................... 1
Changes to Table 1............................................................................ 3
Changes to Table 5............................................................................ 6
Added Figure 5; Renumbered Sequentially .................................. 7
Changes to Table 6............................................................................ 7
Changes to PCB Layout Section and Figure 45 Caption........... 28
Added Figure 46.............................................................................. 28
Updated Outline Dimensions ....................................................... 29
Changes to Ordering Guide .......................................................... 29
Changed GND to Power Ground Throughout .............................6
Changed IL to IL, ILED to ILED, LED OUT to LED_OUT, and
IBAT to IBAT Throughout ..................................................................8
Change to Figure 10 Caption ...........................................................8
Change to Figure 11 Caption ...........................................................9
Changed LED_MOD = 10 to LED_MOD = 11 in Figure 32 ... 14
Changes to Analog-to-Digital Converter Operation Section and
Figure 37 .......................................................................................... 15
Changes to Selecting the Output Capacitor Section.................. 26
2/11—Rev. A to Rev. B
Changes to Features Section and General Description Section . 1
Changes to Switching Regulator, Voltage Output Mode, VOUT
Voltage Parameter and Digital Inputs/GPIO, Torch Glitch
Filtering Delay Parameter, Table 1.................................................. 3
5/10—Revision 0: Initial Version
6/10—Rev. 0 to Rev. A
Changes to Contact Information.....................................................1
Rev. C | Page 2 of 32
ADP1650
SPECIFICATIONS
VIN 1 = 3.6 V, TJ = −40°C to +125°C for minimum/maximum specifications, and TA = 25°C for typical specifications, unless otherwise noted.
Table 1.
Parameter 2
SUPPLY
Input Voltage Range
Undervoltage Lockout Threshold
Undervoltage Lockout Hysteresis
Shutdown Current (IQ), EN = 0 V
Standby Current (ISTBY), EN = 1.8 V
Operating Quiescent Current
SW Switch Leakage
LED DRIVER
LED Current
Assist Light, Torch
Flash
LED Current Error—WLCSP
LED Current Error—LFCSP
LED Current Source Headroom—WLCSP
LED Current Source Headroom—LFCSP
LED_OUT Ramp-Up Time
LED_OUT Ramp-Down Time
SWITCHING REGULATOR
Switching Frequency
Minimum Duty Cycle
nFET Resistance—WLCSP
pFET Resistance—WLCSP
nFET Resistance—LFCSP
pFET Resistance—LFCSP
Voltage Output Mode
VOUT Voltage—WLCSP
VOUT Voltage—LFCSP
Output Current
Line Regulation
Load Regulation
Conditions
Min
VIN falling
2.7
2.3
50
TJ = −40°C to +85°C, current into VIN pin, VIN = 2.7 V to 4.5 V
TJ = −40°C to +85°C, current into VIN pin, VIN = 2.7 V to 4.5 V
Torch mode, LED current = 100 mA
TJ = −40°C to +85°C, VSW 3 = 4.5 V
TJ = 25°C, VSW 3 = 4.5 V
Assist light value setting = 0 (000 binary)
Assist light value setting = 7 (111 binary)
Flash value setting = 0 (00000 binary)
Flash value setting = 24 (11000 binary)
ILED = 700 mA to 1100 mA
ILED = 300 mA to 650 mA, 1150 mA to 1500 mA
ILED = 75 mA to 200 mA
ILED = 25 mA to 50 mA
ILED = 700 mA to 1100 mA
ILED = 300 mA to 650 mA, 1150 mA to 1500 mA
ILED = 75 mA to 200 mA
ILED = 25 mA to 50 mA
Flash, 1200 mA LED current
Torch, 200 mA LED current
Flash, 1200 mA LED current
Torch, 200 mA LED current
Typ
2.4
100
0.2
3
5.3
Max
Unit
5.0
2.5
150
1
10
V
V
mV
μA
μA
mA
μA
μA
2
0.5
25
200
300
1500
−6
−7
−10
−15
−6
−7
−10
−15
+6
+7
+10
+15
+6
+7
+10
+18
290
190
370
220
0.6
0.1
Switching frequency = 3 MHz
Switching frequency = 1.5 MHz
Switching frequency = 3 MHz
Switching frequency = 1.5 MHz
ILOAD at VOUT = 300 mA
Rev. C | Page 3 of 32
mA
mA
mA
mA
%
%
%
%
%
%
%
%
mV
mV
mV
mV
ms
ms
2.8
1.4
3
1.5
14
7
60
50
77
85
3.2
1.6
MHz
MHz
%
%
mΩ
mΩ
mΩ
mΩ
4.575
4.575
5.000
5.000
5.425
5.500
500
V
V
mA
%/V
%/A
0.3
−0.7
ADP1650
Parameter 2
Pass-Through Mode Transition, Flash
VIN to LED_OUT, Entry
VIN to LED_OUT, Exit
Pass-Through Mode Transition, Torch
VIN to LED_OUT, Entry
VIN to LED_OUT, Exit
DIGITAL INPUTS/GPIO
Input Logic Low Voltage
Input Logic High Voltage
GPIO1, GPIO2, STROBE Pull-Down
Torch Glitch Filtering Delay
INDICATOR LED
LED Current Accuracy
Short-Circuit Detection Threshold
Open-Circuit Detection Threshold
ADC
Resolution
Error
Input Voltage Range, GPIO2
SAFETY FEATURES
Maximum Timeout For Flash
Timer Accuracy
DC Current Limit
Low VBAT Mode Transition Voltage
Error
Hysteresis
Coil Peak Current Limit
Conditions
Min
Typ
Max
Unit
1200 mA LED current
1200 mA LED current
580
435
mV
mV
200 mA LED current
200 mA LED current
380
285
mV
mV
0.54
1.26
From torch rising edge to device start
5.5
390
7
−22
7.5
+22
1.2
2.45
4
External voltage mode
VF mode, TJ = 25°C
VF mode, TJ = −40°C to +125°C
External voltage mode
0
0
DC current value setting = 0 (00 binary)
DC current value setting = 1 (01 binary)
DC current value setting = 2 (10 binary)
DC current value setting = 3 (11 binary)
−7.0
1.35
1.55
1.8
2.02
Bits
LSB
LSB
LSB
V
+7.0
1.65
1.95
2.2
2.5
ms
%
A
A
A
A
3.2
Peak current value setting = 0 (00 binary)
Peak current value setting = 1 (01 binary)
Peak current value setting = 2 (10 binary)
Peak current value setting = 3 (11 binary)
Overvoltage Detection Threshold
LED_OUT Short-Circuit Detection
Comparator Reference Voltage
Thermal Shutdown Threshold
TJ Rising
TJ Falling
1.55
2.02
2.47
2.7
5.15
50
1.75
2.25
2.75
3.0
5.5
1.2
150
140
1
VIN is the input voltage to the circuit.
All limits at temperature extremes are guaranteed via correlation using standard statistical quality control (SQC).
3
VSW is the voltage on the SW switch pin.
2
Rev. C | Page 4 of 32
%
V
V
±1
±1
±1.5
0. 5
1600
1.5
1.75
2.0
2.25
V
V
kΩ
ms
1.95
2.5
3.0
3.3
5.9
1.3
%
mV
A
A
A
A
V
V
°C
°C
ADP1650
RECOMMENDED SPECIFICATIONS: INPUT AND OUTPUT CAPACITANCE AND INDUCTANCE
Table 2.
Parameter
CAPACITANCE
Input
Output
MINIMUM AND MAXIMUM INDUCTANCE
Symbol
CMIN
L
Conditions
Min
Typ
Max
Unit
TA = −40°C to +125°C
TA = −40°C to +125°C
TA = −40°C to +125°C
4.0
3.0
0.6
10
10
1.0
20
1.5
μF
μF
μH
I2C-COMPATIBLE INTERFACE TIMING SPECIFICATIONS
Table 3.
Parameter 1
fSCL
tHIGH
tLOW
tSU, DAT
tHD, DAT
tSU, STA
tHD, STA
tBUF
tSU, STO
tR
tF
tSP
CB 2
2
Max
400
0.6
1.3
100
0
0.6
0.6
1.3
0.6
20 + 0.1 CB 2
20 + 0.1 CB2
0
Unit
kHz
μs
μs
ns
μs
μs
μs
μs
μs
ns
ns
ns
pF
0.9
300
300
50
400
Description
SCL clock frequency
SCL high time
SCL low time
Data setup time
Data hold time
Setup time for repeated start
Hold time for start/repeated start
Bus free time between a stop and a start condition
Setup time for stop condition
Rise time of SCL and SDA
Fall time of SCL and SDA
Pulse width of suppressed spike
Capacitive load for each bus line
Guaranteed by design.
CB is the total capacitance of one bus line in picofarads.
SDA
tLOW
tR
tF
tSU, DAT
tF
tHD, STA
tSP
tBUF
tR
SCL
S
tHD, DAT
tHIGH
tSU, STA
Sr
S = START CONDITION
Sr = REPEATED START CONDITION
P = STOP CONDITION
tSU, STO
P
S
08837-003
1
Min
Figure 3. I2C-Compatible Interface Timing Diagram
Rev. C | Page 5 of 32
ADP1650
ABSOLUTE MAXIMUM RATINGS
THERMAL RESISTANCE
Table 4.
Parameter
VIN, SDA, SCL, EN, GPIO1, GPIO2, STROBE,
LED_OUT, SW, VOUT to Power Ground
PGND to SGND
Ambient Temperature Range (TA)
Junction Temperature Range (TJ)
Storage Temperature
ESD Human Body Model
ESD Charged Device Model
ESD Machine Model
Rating
−0.3 V to +6 V
−0.3 V to +0.3 V
−40°C to +85°C
−40°C to +125°C
JEDEC J-STD-020
±2000 V
±500 V
±150 V
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
θJA of the package is based on modeling and calculation using
a 4-layer board. θJA is highly dependent on the application and
board layout. In applications where high maximum power dissipation exists, attention to thermal board design is required. The
value of θJA may vary, depending on PCB material, layout, and
environmental conditions. The specified value of θJA is based
on a 4-layer, 4 in × 3 in, 2 ½ oz copper board, per JEDEC
standards. For more information, see the AN-617 Application
Note, MicroCSP™ Wafer Level Chip Scale Package.
θJA is specified for a device mounted on a JEDEC 2S2P PCB.
Table 5. Thermal Resistance
Package Type
12-Ball WLCSP
10-Lead LFCSP
ESD CAUTION
THERMAL DATA
The ADP1650 may be damaged if the junction temperature
limits are exceeded. Monitoring TA does not guarantee that TJ
is within the specified temperature limits. In applications with
high power dissipation and poor thermal resistance, the maximum
TA may have to be derated. In applications with moderate power
dissipation and low PCB thermal resistance, the maximum TA
can exceed the maximum limit as long as the TJ is within specification limits. TJ of the device is dependent on the TA, the power
dissipation (PD) of the device, and the junction-to-ambient
thermal resistance (θJA) of the package. Maximum TJ is
calculated from the TA and PD using the following formula:
TJ = TA + (PD × θJA)
Rev. C | Page 6 of 32
θJA
75
42.5
Unit
°C/W
°C/W
ADP1650
PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS
BALL A1
INDICATOR
1
2
3
PGND
SGND
VIN
SW
GPIO2
GPIO1
VOUT
STROBE
EN
A
B
VIN 1
GPIO2 2
GPIO1 3
LED_OUT
SDA
SDA 4
SCL
SCL 5
D
ADP1650
TOP VIEW
9
EN
8
SW
7
VOUT
6
LED_OUT
NOTES
1. THE EXPOSED PADDLE MUST BE CONNECTED
TO GROUND.
08837-004
TOP VIEW
(BALL SIDE DOWN)
Not to Scale
10 STROBE
Figure 4. WLCSP Pin Configuration
08837-070
C
Figure 5. LFCSP Pin Configuration
Table 6. Pin Function Descriptions
WLCSP
A1
A2
A3
B1
B2
Pin No.
LFCSP
N/A 1
N/A1
1
8
2
Mnemonic
PGND
SGND
VIN
SW
GPIO2
B3
3
GPIO1
C1
7
VOUT
C2
10
STROBE
C3
9
EN
D1
D2
D3
6
4
5
0
LED_OUT
SDA
SCL
EPAD
1
Description
Power Ground.
Signal Ground.
Input Voltage for the Device. Connect an input bypass capacitor close to this pin.
Boost Switch. Connect the power inductor between SW and the input capacitor.
ILED/TX2/ADC. Mode is register selectable. Red indicator LED current source or
TxMASK2 or ADC input.
ILED Mode. Connect to red LED anode. Connect the LED cathode to power ground.
TxMASK2 Mode. Reduces the current to the programmable TxMASK2 current.
ADC Mode. This pin is used as the input pin for the ADC.
Torch/TX1. Mode is register selectable. External torch mode or TxMASK1 input.
Torch Mode. Enables the integrated circuit (IC) in direct torch mode.
TxMASK1 Mode. Reduces the flash current to the programmable TxMASK1 current.
Boost Output. Connect an output bypass capacitor very close to this pin. This is the
output for the 5 V external voltage mode.
Strobe Signal Input. This pin synchronizes the flash pulse to the image capture. In
most cases, this signal comes directly from the image sensor.
Enable. Set EN low to bring the quiescent current (IQ) to