Data Sheet
FEATURES
Charge Pump, 7-Channel
Smart LED Driver with I
2
C Interface
ADP8861
TYPICAL OPERATING CIRCUIT
Charge pump with automatic gain selection of 1×, 1.5×, and 2×
for maximum efficiency
7 independent, programmable LED drivers
7 drivers capable of 30 mA (typical)
1 driver also capable of 60 mA (typical)
Programmable maximum current limit (128 levels)
Standby mode for <1 μA current consumption
16 programmable fade in and fade out times
0.1 sec to 5.5 sec
Choose from linear, square, or cubic rates
Fading override
I
2
C-compatible interface for all programming
Dedicated reset pin and built-in power-on reset (POR)
Short-circuit, overvoltage, and overtemperature protection
Internal soft start to limit inrush currents
Input-to-output isolation during faults or shutdown
Operation down to V
IN
= 2.5 V with undervoltage lockout
(UVLO) at V
IN
= 2.0 V
Available in a small 20-ball, 2.15 mm × 2.36 mm × 0.6 mm
WLCSP or a 20-lead, 4 mm × 4 mm × 0.75 mm LFCSP
D1
VIN
D2
D3
D4
D5
D6
D7
C
IN
1µF
VDDIO
VOUT
C
OUT
1µF
C1+
nRST
VDDIO
ADP8861
SDA
VDDIO
C1–
C2+
C2–
C1
1µF
SCL
VDDIO
C2
1µF
nINT
GND1
GND2
08391-001
Figure 1.
APPLICATIONS
Mobile display backlighting
Mobile phone keypad backlighting
Dual RGB backlighting
LED indication
General backlighting of small format displays
GENERAL DESCRIPTION
The
ADP8861
provides a powerful charge pump driver with
independent control of up to seven LEDs. These seven LEDs
can be independently driven up to 30 mA (typical). The seventh
LED can also be driven to 60 mA (typical). All LEDs are pro-
grammable for maximum current and fade in/out times via
the I
2
C interface. These LEDs can also be combined into groups to
reduce the processor instructions during fade in/out.
This entire configuration is driven by a two-capacitor charge
pump with gains of 1×, 1.5×, and 2×. The charge pump is
capable of driving a maximum I
OUT
of 240 mA from a supply
of 2.5 V to 5.5 V. A full suite of safety features, including short-
circuit, overvoltage, and overtemperature protection, allows
easy implementation of a safe and robust design. Additionally,
input inrush currents are limited via an integrated soft start
combined with controlled input-to-output isolation.
Rev. C
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•
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ADP8861
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications ....................................................................................... 1
Typical Operating Circuit ................................................................ 1
General Description ......................................................................... 1
Revision History ............................................................................... 2
Specifications..................................................................................... 3
I
2
C Timing Diagram .................................................................... 4
Absolute Maximum Ratings ............................................................ 5
Maximum Temperature Ranges ................................................. 5
Thermal Resistance ...................................................................... 5
ESD Caution .................................................................................. 5
Pin Configurations and Function Descriptions ........................... 6
Typical Performance Characteristics ............................................. 7
Theory of Operation ...................................................................... 11
Power Stage.................................................................................. 12
Operating Modes ........................................................................ 13
Backlight Operating Levels ....................................................... 14
Backlight Maximum and Dim Settings ................................... 14
Data Sheet
Automated Fade In and Fade Out ............................................ 14
Backlight Turn On/Turn Off/Dim ........................................... 15
Automatic Dim and Turn Off Timers ..................................... 15
Fade Override ............................................................................. 16
Independent Sink Control ........................................................ 16
Short-Circuit Protection Mode ................................................ 16
Overvoltage Protection .............................................................. 17
Thermal Shutdown/Overtemperature Protection ................. 17
Interrupts ..................................................................................... 17
Applications Information .............................................................. 19
Determining the Transition Point of the Charge Pump ....... 19
Layout Guidelines....................................................................... 19
Example Circuits ........................................................................ 20
I
2
C Programming and Digital Control ........................................ 21
Backlight Register Descriptions ............................................... 26
Independent Sink Register Descriptions................................. 31
Outline Dimensions ....................................................................... 39
Ordering Guide .......................................................................... 40
REVISION HISTORY
2/2017—Rev. B to Rev. C
Updated Outline Dimensions ....................................................... 39
Changes to Ordering Guide .......................................................... 40
4/2012—Rev. A to Rev. B
Changes to Table 1 ............................................................................ 4
Updated Outline Dimensions ....................................................... 40
Changes to Ordering Guide .......................................................... 40
6/2010—Rev. 0 to Rev. A
Changes to Features Section and General Description Section . 1
Changes to Thermal Resistance Section and Table 3................... 5
Added Figure 4; Renumbered Sequentially .................................. 6
Changes to Table 4 ............................................................................ 6
Changes to Layout Guidelines Section ........................................ 19
Updated Outline Dimensions ....................................................... 39
Changes to Ordering Guide .......................................................... 40
4/2010—Revision 0: Initial Version
Rev. C | Page 2 of 40
Data Sheet
SPECIFICATIONS
ADP8861
VIN = 3.6 V, SCL = 2.7 V, SDA = 2.7 V, nINT = open, nRST = 2.7 V, V
D1:D7
= 0.4 V, Capacitor C1 = 1 μF, Capacitor C2 = 1 μF, C
OUT
= 1 μF,
typical values are at T
A
= 25°C and are not guaranteed, minimum and maximum limits are guaranteed from T
A
= −40°C to +85°C, unless
otherwise noted.
Table 1.
Parameter
SUPPLY
Input Voltage
Operating Range
Start-Up Level
Low Level
V
IN(START)
Hysteresis
UVLO Noise Filter
Quiescent Current
Prior to V
IN(START)
During Standby
After Startup and Switching
OSCILLATOR
Switching Frequency
Duty Cycle
OUTPUT CURRENT CONTROL
Maximum Drive Current
Diode1 to Diode 7
T
J
= 25°C
T
J
= −40°C to +85°C
Diode 7 Only (60 mA Setting)
T
J
= 25°C
T
J
= −40°C to +85°C
LED Current Source Matching
1
All Current Sinks
Diode 2 to Diode 7 Current
Sinks
Leakage Current on LED Pins
Equivalent Output Resistance
Gain = 1×
Gain = 1.5×
Gain = 2×
Regulated Output Voltage
AUTOMATIC GAIN SELECTION
Minimum Voltage
Gain Increases
Minimum Current Sink Headroom
Voltage
Gain Delay
Symbol
Test Conditions/Comments
Min
Typ
Max
Unit
V
IN
V
IN(START)
V
IN(STOP)
V
IN(HYS)
t
UVLO
I
Q
I
Q(START)
I
Q(STBY)
I
Q(ACTIVE)
f
SW
D
I
D1:D7(MAX)
2.5
V
IN
increasing
V
IN
decreasing
After startup
1.75
2.05
1.97
80
10
10
0.3
4.5
0.8
1
50
5.5
2.30
V
V
V
mV
μs
μA
μA
mA
MHz
%
V
IN
= V
IN(START)
− 100 mV
V
IN
= 3.6 V, Bit nSTBY = 0, SCL = SDA = 0 V
V
IN
= 3.6 V, Bit nSTBY = 1, I
OUT
= 0 mA, gain = 2×
Charge pump gain = 2×
1.0
7.2
1.32
V
D1:D7
= 0.4 V
Bit SCR = 0 in the ISC7 register
26.2
24.4
30
34.1
34.1
67
67
mA
mA
mA
mA
%
%
0.5
0.5
3.0
3.8
4.9
μA
Ω
Ω
Ω
V
I
D7(60 mA)
V
D7
= 0.4 V, Bit SCR = 1 in the ISC7 register
52.5
48.8
60
I
MATCH
I
MATCH7
I
MATCH6
I
D1:D7(LKG)
R
OUT
V
D1:D7
= 0.4 V
V
D2:D7
= 0.4 V
V
IN
= 5.5 V, V
D1:D7
= 2.5 V, Bit nSTBY = 1
V
IN
= 3.6 V, I
OUT
= 100 mA
V
IN
= 3.1 V, I
OUT
= 100 mA
V
IN
= 2.5 V, I
OUT
= 100 mA
V
IN
= 3 V, gain = 2×, I
OUT
= 10 mA
2.0
1.5
V
OUT(REG)
4.3
5.5
V
HR(UP)
V
HR(MIN)
t
GAIN
Decrease V
D1:D7
until the gain switches up
I
DX
= I
DX(MAX)
× 95%
The delay after gain has changed and before
gain is allowed to change again
162
200
180
100
276
mV
mV
μs
Rev. C | Page 3 of 40
ADP8861
Parameter
FAULT PROTECTION
Start-Up Charging Current Source
Output Voltage Threshold
Exit Soft Start
Short-Circuit Protection
Output Overvoltage Protection
Activation Level
OVP Recovery Hysteresis
Thermal Shutdown
Threshold
Hysteresis
Isolation from Input to Output
During Fault
Time to Validate a Fault
2
I C INTERFACE
Operating V
DDIO
Voltage
Logic Low Input
2
Logic High Input
3
I
2
C TIMING SPECIFICATIONS
Delay from Reset Deassertion to
I
2
C Access
SCL Frequency
SCL High Time
SCL Low Time
Setup Time
Data
Repeated Start
Stop Condition
Hold Time
Data
Start/Repeated Start
Bus Free Time (Stop and Start
Conditions)
Rise Time (SCL and SDA)
Fall Time (SCL and SDA)
Pulse Width of Suppressed Spike
Capacitive Load per Bus Line
1
2
Data Sheet
Symbol
I
SS
V
OUT
V
OUT(START)
V
OUT(SC)
V
OVP
Test Conditions/Comments
V
IN
= 3.6 V, V
OUT
= 0.8 × V
IN
V
OUT
rising
V
OUT
falling
Min
2.5
Typ
3.75
0.92 × V
IN
0.55 × V
IN
5.8
500
TSD
TSD
(HYS)
I
OUTLKG
t
FAULT
V
DDIO
V
IL
V
IH
t
RESET
f
SCL
t
HIGH
t
LOW
t
SU, DAT
t
SU, STA
t
SU, STO
t
HD, DAT
t
HD, STA
t
BUF
t
R
t
F
t
SP
C
B
150
20
V
IN
= 5.5 V, V
OUT
= 0 V, Bit nSTBY = 0
2
5.5
0.5
1.55
20
400
0.6
1.3
100
0.6
0.6
0
0.6
1.3
20 + 0.1 C
B
0
0.9
1.5
Max
5.5
Unit
mA
V
V
V
mV
°C
°C
μA
μs
V
V
V
μs
kHz
μs
μs
ns
μs
μs
μs
μs
μs
ns
ns
ns
pF
V
IN
= 2.5 V
V
IN
= 5.5 V
Guaranteed by design
300
300
50
400
Current source matching is calculated by dividing the difference between the maximum and minimum currents from the sum of the maximum and minimum.
V
IL
is a function of the input voltage. See Figure 16 in the Typical Performance Characteristics section for typical values over operating ranges.
3
V
IH
is a function of the input voltage. See Figure 16 in the Typical Performance Characteristics section for typical values over operating ranges.
I
2
C TIMING DIAGRAM
SDA
t
LOW
SCL
t
R
t
SU, DAT
t
F
t
F
t
HD, STA
t
SP
t
R
t
BUF
S
t
HD, DAT
t
HIGH
t
SU, STA
Sr
t
SU, STO
P
S
08391-002
S = START CONDITION
Sr = REPEATED START CONDITION
P = STOP CONDITION
Figure 2. I
2
C Interface Timing Diagram
Rev. C | Page 4 of 40
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