BL8088

BL8088
8-Channel WLED Linear Driver
DESCRIPTION
FEATURES
The BL8088 is a CMOS based White/Blue LED
driver with stand-alone capability. The driver is
primarily designed for LED backlighting of LCD
display powered by Li-ion battery. With its high
efficiency, low standby current and wide range of
input supply voltage, the BL8088 is suitable for
applications such as portable device display and
keypad backlighting. There are eight identical
channels in BL8088, each of which can drive one
LED by current rating of 20mA.
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BL8088 is available with QFN 3X3-16 package
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TYPICAL APPLICATION
PIN ASSIGNMENT
APPLICATIONS
BLOCK DIAGRAM
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1
9
D4
D3
8
10
D5
7
11
D6
6
12
KD
LLNYW
NC
GND
D1
5
13
14
D7
EN
4
D8 D7
D8
NC
3
GND
VIN
NC
2
LC1988
BL8088
NC
NC
1
EN
D1
D2
D3
D4
D5
D6
LCD screen backlights driver
Mobile phone, portable device keypad
backlights driver
15
VIN
1uF
EN

16
Vin

8-channel output
2.7 to 5.5V input range
PWM dimming control, suggested 1KHz
LED sink current of 20mA
Independent current sink circuit for each LED
output
Low standby current
High accuracy current match on each channel
D2
BL8088
MARKING INFORMATION
ORDERING INFORMATION
BL8088 □
1 □
2 □
3
10
9
4
D5
D4
D3
8
11
D6
NC
7
12
KD
LLNYW
1
□
GND
6
EN
D1
5
NC
3
D7
NC
2
D8
NC
1
13
VIN
15
NC
16
KC: Product Code
LL: LOT No.
KC
N: FAB Code
LLNYW
Y: Year No.
W: Week No.
Code
BL8088CJKTR
14
Product Classification
Marking
D2
2
□
3
□
Description
Temperature & Rohs:
C: -40~85C, Pb Free Rohs Std.
Package type:
JK: QFN 3X3 –16
Packing type:
TR: Tape&Reel (Standard)
Top view
PIN DESCRIPTION
Name
D1-D8
EN
VIN
GND
NC
Function Description
RGB or WLED Cathode Connection Pin
Chip Enable and Dimming Control.
Power Supply
Ground
Not Connected
ABSOLUTE MAXIMUM RATING
Supply voltage
–0.3V to 7V
Voltage of LEDn, EN pin
Maximum Junction Temperature
Operating Ambient Temperature Range
Storage Temperature Range
Lead Temperature (Soldering, 10 sec)
–0.3V to 7V
125°C
–40°C to 85°C
–40°C to 150°C
260°C
Note: Exceed these limits to damage to the device.
Note: Exposure to absolute maximum rating conditions may affect device reliability.
RECOMMENDED OPERATING CONDITIONS
Items
Supply Voltage Range
Operating Temperature
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MIN
2.7
-25
2
MAX
5.5
85
Unit
V
°C
BL8088
ELECTRICAL CHARACTERISTICS
VCC=3.7V, Ta=25°C, No Load, Input: VEN=3.7V. (Unless otherwise noted)
Conditions
SPEC
TYP
Symbols
Parameters
VIL
VIH
IIL
IIH
VLEDL
ILED
ILEDn
IQ
ISTBY
EN Pin “Low” Logic
EN Pin “High” Logic
1.7
V
V
EN Pin “Low” Input Current
-1
uA
EN Pin “High” Input Current
LEDn Dropout Voltage
LEDn Sink Current
LEDn Sink Current Deviation
MIN
MAX
0.4
1
18
100
20
-5
Quiescent Current
500
Standby Supply Current
VEN=”0”
0.5
Unit
22
5
uA
mV
mA
%
800
uA
uA
DETAILED DESCRIPTION
BL8088 works with a wide range of supply voltage, from 2.7V to 6V. The forward voltage of commercial
white/blue LED is in the range of 2.9V to 3.5V at a current level of 20mA. Proper selection of the LED to
match the supply voltage can fully utilize the Li-ion battery. For example, there is 1% ~ 3 % power left in the
Li-ion battery when its voltage reaches 3.275V. So a LED with a forward voltage value of 3.2V can use up to
99% of the battery power under normal working condition. When the voltage of the battery drops below
3.2V, the current through the LED (hence the brightness) starts to decrease.
Due to its uniquely designed current regulator, BL8088 offers low output dropout and provide superior
efficiency performance over standard Inductive boost type and capacitive charge pump type LED driver.
The EN pin controls the on/off state of the device. A high level state turns on the device and a low level
turns off the device, results in the low off state current. This pin needs to be terminated since a floating
level of the EN pin will cause the instability of the device.
The sink current has a constant value of 20mA. The
brightness of the LED can be adjusted by controlling the duty
cycle of the BL8088’s LEDn output. This can be accomplished
by applying a PWM signal to the EN pin. In BL8088, the
internal power on sequence presents a delay time of 6us
from EN pin to LEDn pin. Hence, in order to modulate the
output of LEDn in every cycle normally, the width of dimming
signal applied EN pin have to be no less than 6us. For
example, when a dimming signal of 20KHz is applied, the
minimum range of dimming is about 12%, that is, the average
output current on each channel is 2.4mA.
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3
BL8088
TYPICAL PERFORMANCE CHARACTERISTICS
Quiescent Current vs Temperature
(VCC=3.7V)
350
450
300
400
Quiescent Current (uA)
Quiescent Current (uA)
Quiescent Current vs Supply Current
(Ta=25℃)
250
200
150
100
50
350
300
250
200
150
100
50
0
0
3.0
3.5
4.0
4.5
-40 -20
5.0
ILED vs Supply Voltage
25
20
20
LED Current (mA)
ILED (mA)
22
18
16
14
10
3.3 3.4 3.5 3.6 3.7 3.8 3.9 4.0 4.1 4.2
0
0.01
Supply Voltage (V)
ILED (mA)
20.2
20.2
20.1
20.1
20.0
20.0
19.9
19.9
19.8
19.8
19.7
50
75
100
125
Temperature (℃)
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80
100 120 140
0.1
1
LEDn Dropout Voltage (V)
ILED vs Temperature
(VCC=3.7V)
25
60
10
5
0
40
15
12
-25
20
ILED vs LEDn Dropout Voltage
(VCC=3.7V)
(VCC=3.7V, VLEDn=3.2V)
-50
0
Temperature (℃)
Supply Voltage (V)
4
10
BL8088
PACKAGE INFORMATION
Package
QFN3X3-16
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Devices per reel
5
3000
Unit
mm