LDS8866
6-Channel Ultra Low Dropout LED Driver
FEATURES
o
o
o
o
o
o
o
o
o
o
o
o
o
High efficiency 1.33x charge pump
Ultra low dropout PowerLite Current
Regulator*
Multi-mode charge pump: 1x, 1.33x, 1.5x, 2x
Drives up to 6 LEDs at 32mA each
Factory preset current value at each LED
bank in 0.5mA steps
PWM brightness control
Power efficiency up to 95%
Low noise input ripple in all modes
Low current shutdown mode
Soft start and current limiting
Short circuit protection
Thermal shutdown protection
Tiny 3 x 3 mm 16-pin TQFN package
dropout PowerLite Current Regulator increases
device’ efficiency up to 95%. New mode requires no
additional external capacitors.
The PWM1/PWM2 logic inputs function as a chip
enable and a PWM mode LED brightness control.
PWM1 pin contorls LEDA and LEDB banks with four
LEDs, while PWM2 controls bank with two LEDs.
The maximum LEDs current is factory preset. Every
LED bank with two LEDs each programmed
separately in the range from 0.5 to 32mA in 0.5mA
steps.
Low noise input ripple is achieved by operating at a
constant switching frequency which allows the use of
small external ceramic capacitors. The multi-
fractional charge pump supports a wide range of
input voltages from 2.7V to 5.5V.
The device is available in in 16-lead TQFN 3mm x
3mm package with a max height of 0.8mm.
APPLICATION
o
o
o
o
LCD Display Backlight
Cellular Phones
Digital Still Cameras
Handheld Devices
DESCRIPTION
The LDS8866 is a high efficiency multi-mode
fractional charge pump with ultra low feedback
voltage that can drive up to six LEDs. Inclusion of a
1.33x fractional charge pump mode and ultra low
TYPICAL APPLICATION CIRCUIT
___________________________________
*) Leadis Technology patent pending
© 2007 Leadis Technology
Characteristics subject to change without notice
1
Doc. No. 8866DS, Rev. 0.22
LDS8866
ABSOLUTE MAXIMUM RATINGS
Parameter
Vin, LEDx, C1±, C2± voltage
Vout voltage
PWM1, PWM2 voltage
Storage Temperature Range
Junction Temperature Range
Lead Temperature
Rating
6
6
Vin + 0.7V
-65 to +160
-40 to +125
300
Unit
V
V
V
°C
°C
°C
RECOMMENDED OPERATING CONDITIONS
Parameter
Vin
Ambient Temperature Range
I
LED
per LED pin
Total Output Current
Rating
2.7 to 5.5
-40 to +85
0 to 32
0 to 192
Unit
V
°C
mA
mA
ELECTRICAL OPERATING CHARACTERISTICS
(Over recommended operating conditions unless specified otherwise) Vin = 3.6V, EN = High, T
AMB
= 25°C
Name
Quiescent Current
Shutdown Current
LED Current Accuracy
LED Channel Matching
Output Resistance (open loop)
Conditions
1x mode, no load
1.33 x mode, no load
1.5x mode, no load
2x mode, no load
V
PWM
= 0V
To factory preset value
(I
LED
- I
LEDAVG
) / I
LEDAVG
1x mode
1.33x mode, Vin = 3V
1.5x mode, Vin = 2.7V
2x mode, Vin = 2.4V
1.33x and 2x mode
1.5x mode
Vout < 0.5V
Vout > 1V
Min
Typ
0.5
3.5
3
2.5
±3
±1
0.5
3.5
4.5
6
0.8
1.1
80
450
50
400
500
Max
Units
mA
1
µA
%
%
Ω
Charge Pump Frequency
Output short circuit Current Limit
Input Current Limit
1x to 1.33x, 1.33x to 1.5x, or 1.5x to 2x
Transition Thresholds at any LED pin
1.33x to 1x Mode Transition Hysteresis
Transition Filter Delay
PWM1,
Input Leakage
PWM2
High
Logic Level
pins
Low
PWM frequency
PWM duty cycle
Thermal Shutdown
Thermal Hysteresis
Under Voltage Lockout (UVLO)
Threshold
Over Voltage Protection
0.6
0.8
1.1
1.4
MHz
mA
mA
mV
mV
µs
µA
V
Hz
%
°C
-1
1.3
100
1
150
20
2.0
1
0.4
10000
100
6.2
V
V
© 2007 Leadis Technology
Characteristics subject to change without notice
2
Doc. No. 8866DS, Rev. 0.22
LDS8866
TYPICAL CHARACTERISTICS
Vin = 3.6V, I
OUT
= 120mA (6 LEDs at 20mA), C
1
= C
2
= C
IN
= C
OUT
= 1μF, T
AMB
= 25°C unless otherwise specified
Efficiency vs. Input Voltage
Efficiency vs. Li-Ion Voltage
LED Current Change vs. Input Voltage
LED Current Change vs. Temperature
Switching Frequency vs. Temperature
Output resistance vs. Input Voltage
© 2007 Leadis Technology
Characteristics subject to change without notice
3
Doc. No. 8866DS, Rev. 0.22
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
