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ADP8860 Schematic ( PDF Datasheet ) - Analog Devices

Teilenummer ADP8860
Beschreibung 7-Channel Smart LED Driver
Hersteller Analog Devices
Logo Analog Devices Logo 




Gesamt 30 Seiten
ADP8860 Datasheet, Funktion
Charge Pump, 7-Channelwww.DataSheet4U.com
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 combi-
nation 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
VDDIO
A2
0.1µF
VOUT
1µF
nRST
E1
VDDIO
SDA
C2
VDDIO
SCL
E2
VDDIO
ADP8860
A1 C1+
C1–
C1
B1 C2+
C2–
B2
C1
1µF
C2
1µF
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/max-
imum 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. Addi-
tionally, 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. 0
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibilityisassumedbyAnalog Devicesforitsuse,norforanyinfringementsofpatentsorother
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.
Trademarks and registered trademarks are the property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
www.analog.com
Fax: 781.461.3113
©2009 Analog Devices, Inc. All rights reserved.






ADP8860 Datasheet, Funktion
ADP8860
ABSOLUTE MAXIMUM RATINGS
Table 2.
Parameter
VIN, VOUT
D1, D2, D3, D4, D5, D6, and D7
CMP_IN
nINT, nRST, SCL, and SDA
Output Short-Circuit Duration
Operating Ambient Temperature Range
Operating Junction Temperature Range
Storage Temperature Range
Soldering Conditions
ESD (Electrostatic Discharge)
Human Body Model (HBM)
Charged Device Model (CDM)
Rating
−0.3 V to +6 V
−0.3 V to +6 V
−0.3 V to +6 V
−0.3 V to +6 V
Indefinite
–40°C to +85°C1
–40°C to +125°C
–65°C to +150°C
JEDEC J-STD-020
±2 kV
±2 kV
1 The maximum operating junction temperature (TJ(MAX)) supersedes the
maximum operating ambient temperature (TA(MAX)). See the Maximum
Temperature Ranges section for more information.
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.
Absolute maximum ratings apply individually only, not in
combination. Unless otherwise specified, all voltages are
referenced to GND.
MAXIMUM TEMPERATURE RANGES
The maximum operating junction temperature (TJ(MAX))
supersedes the maximum operating ambient temperature
(TA(MAX)). Therefore, in situations where the ADP8860 is
exposed to poor thermal resistance and a high power
dissipation (PD), the maximum ambient temperature may need
to be derated. In these cases, the ambient temperature
maximum can be calculated with the following equation:
TA(MAX) = TJ(MAX) − (θJA × PD(MAX))
www.DataSheet4U.com
THERMAL RESISTANCE
θJA (junction to air) is specified for the worst-case conditions,
that is, a device soldered in a circuit board for surface-mount
packages. The θJA, θJB (junction to board), and θJC (junction to
case) are determined according to JESD51-9 on a 4-layer
printed circuit board (PCB) with natural convection cooling.
For the LFCSP package, the exposed pad must be soldered to
the GND1 and/or GND2 terminal(s) on the board.
Table 3. Thermal Resistance1
Package Type θJA
θJB
WLCSP
48 9
LFCSP_VQ
49.5 N/A
1 N/A means not applicable.
θJC
N/A
5.3
Unit
°C/W
°C/W
ESD CAUTION
Rev. 0 | Page 6 of 52

6 Page









ADP8860 pdf, datenblatt
ADP8860
THEORY OF OPERATION
The ADP8860 combines a programmable backlight LED charge
pump driver with automatic phototransistor control. This combi-
nation allows for significant power savings because it is able to
change the current intensity based on the lighting conditions. It
performs this function automatically thereby removing the
need for a processor to monitor the phototransistor. The light
intensity levels are fully programmable via the I2C interface. A
second phototransistor input, with dedicated comparators,
improves the ambient light detection abilities for various user-
operating conditions.
www.DataSheet4U.com
The ADP8860 allows up to seven LEDs to be independently
driven up to 30 mA (typical). The seventh LED can also be
driven to 60 mA (typical). All LEDs can be individually pro-
grammed or combined into a group to operate backlight LEDs.
A full set of safety features including short-circuit, overvoltage,
and overtemperature protection with input-to-output isolation
allow for a robust and safe design. The integrated soft start
limits inrush currents at startup, restart attempts, and gain
transitions.
OPTIONAL
PHOTOSENSOR
VALS
D3 D1 E3 D2 E4 D3 D4 D4 C4 D5 B4 D6 B3 D7
ID1 ID2 ID3 ID4 ID5 ID6 ID7
GAIN
SELECT
LOGIC
CMP_IN
C3
PHOTOSENSOR
CONVERSION
VIN
ISS
VBAT
A3
CIN
VDDIO
E1
nRST
SCL
E2
SDA
C2
nINT
D2
VIN
UVLO
STNDBY
NOISE FILTER
50µs
VIN
EN
VREFS
IREFS
CLK
LIGHT
SENSOR
LOGIC
RESET
STNDBY
I2C
LOGIC
SWITCH CONTROL
ILED CONTROL
CHARGE
PUMP
LOGIC
SOFT START
CHARGE
PUMP
(1×, 1.5×, 2×)
VOUT
A2
COUT
A1 C1+
C1 C1–
B1 C2+
B2 C2–
C1
1µF
C2
1µF
A4
GND1
D1
GND2
Figure 26. Detailed Block Diagram
Rev. 0 | Page 12 of 52

12 Page





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