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Data Sheet
Charge Pump, 7-Channel Smart LED Driver with I2C Interface
ADP8860
FEATURES
Charge pump with automatic gain selection of 1×, 1.5×, and 2× for maximum efficiency
Up to two built-in comparator inputs with programmable modes for ambient light sensing
Outdoor, office, and dark modes for maximum backlight power savings
7 independent and programmable LED drivers 6 drivers capable of 30 mA (typical) 1 driver 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 I2C-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 VIN = 2.5 V with undervoltage lockout (UVLO) at VIN = 2.0 V Small wafer level chip scale package (WLCSP) or lead frame chip scale package (LFCSP)
APPLICATIONS
Mobile display backlighting Mobile phone keypad backlighting Dual RGB backlighting LED indication General backlighting of small format displays
GENERAL DESCRIPTION
The ADP8860 combines a programmable backlight LED charge pump driver with automatic phototransistor control. This combination allows for significant power savings because it changes the current intensity in office and dark ambient light conditions. By performing this function automatically, it eliminates the need for a processor to monitor the phototransistor.
The light intensity thresholds are fully programmable via the I2C® interface. A second phototransistor input, with dedicated comparators, improves the ambient light detection levels for various user operating conditions.
TYPICAL OPERATING CIRCUIT
VOUT
VALS OPTIONAL PHOTOSENSOR
PHOTOSENSOR
0.1µF
VIN 1µF
D1 D2 D3 D4 D5
D7 CMP_IN
D3 E3 E4 D4 C4 B4 B3
C3
A3
D6/
CMP_IN2
A2
VDDIO
0.1µF
VOUT 1µF
nRST
E1
VDDIO
SDA
C2
VDDIO
SCL
E2
VDDIO
ADP8860
C1+
A1
C1 C1– 1µF
C1
C2+
B1
C2
B2 C2–
1µF
07967-001
nINT
D2
A4
GND1
D1
GND2
Figure 1.
The ADP8860 allows as many as six LEDs to be independently driven up to 30 mA (typical). A seventh LED can be driven to 60 mA (typical). All LEDs are programmable for minimum/maximum current and fade in/out times via the I2C interface. These LEDs can also be combined into groups to reduce the processor instructions during fade in/out.
Driving this entire configuration is a two-capacitor charge pump with gains of 1×, 1.5×, and 2×. This setup is capable of driving a maximum IOUT of 240 mA from a supply of 2.5 V to 5.5 V. The device includes a variety of safety features including short-circuit, overvoltage, and overtemperature protection. These features allow 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.
The ADP8860 is available in two package types, either a compact 2 mm × 2.4 mm × 0.6 mm WLCSP (wafer level chip scale package) or a small LFCSP (lead frame chip scale package).
Rev. A
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ADP8860
TABLE OF CONTENTS
Features .............................................................................................. 1 Applications....................................................................................... 1 General Description ......................................................................... 1 Typical Operating Circuit................................................................ 1 Revision History ............................................................................... 2 Specifications..................................................................................... 3
I2C Timing Diagram .................................................................... 4 Absolute Maximum Ratings............................................................ 5
Maximum Temperature Ranges ................................................. 5 Thermal Resistance ...................................................................... 5 ESD Caution.................................................................................. 5 Pin Configurations and.