CAT3626
6-Channel LED Driver with I
2
C™ Interface
FEATURES
Drives 6 LED channels
Independent current on 3 pairs of LEDs
I
2
C serial interface programming
Adjustable current to 32mA in 0.5mA step
Power efficiency up to 91%
Fractional pump 1x/1.5x
Low noise input ripple
Fixed High Frequency Operation 1MHz
“Zero” Current Shutdown Mode
Soft start and current limiting
Short circuit protection
Thermal shutdown protection
PRODUCT DESCRIPTION
The CAT3626 is a high efficiency 1x/1.5x fractional
charge pump with programmable dimming current in
six LED channels. To ensure uniform brightness in
LCD backlight applications, each LED channel delivers
an accurate regulated current.
Low noise and input ripple is achieved by operating at
a constant switching frequency of 1MHz which allows
the use of small external ceramic capacitors. The
1x/1.5x fractional charge pump supports a wide range
of input voltages from 3V to 5.5V with efficiency up to
91%, and is ideal for Li-Ion battery powered devices.
The LED channels are configured into three indepen-
dent pairs, each containing 2 matched channels. Each
pair can be separately programmed from zero to 32mA,
2
in 0.5mA resolution steps, using the I C serial interface.
Any individual channel can be disabled while others
remain active. When the enable input (EN) is low, the
device is in shutdown mode drawing zero current.
The device is available in a 16-pad
TQFN
package
with a max height of 0.8mm.
Package
Marking
G626
CDAJ
APPLICATIONS
RGB LEDs
LCD and keypad Backlighting
Cellular Phones, PDAs
Digital Cameras
ORDERING INFORMATION
Part Number
Package
CAT3626HV4-T2 TQFN-16
(1)
CAT3626HV4-GT2 TQFN-16
(2)
Quantity
per Reel
2000
2000
For Ordering Information details, see page 14.
Notes:
(1) Matte-Tin Plated Finish (RoHS-compliant)
(2) NiPdAu Plated Finish (RoHS-compliant)
PIN CONFIGURATION
TQFN 16-pad 4 x 4mm
(Top View)
LEDA2 LEDB1 LEDB2 LEDC1
16
LEDA1
SDA
SCL
EN
1
2
3
4
5
VOUT
2
TYPICAL APPLICATION CIRCUIT
1µF
1µF
15
14
13
12 LEDC2
11 GND
10 C2+
9 C2-
V
IN
3V to
5.5V
C
IN
1µF
C1-
VIN
C1+
C2-
C2+
VOUT
pair A
pair B
pair C
CAT3626
LEDA1
LEDA2
LEDB1
LEDB2
LEDC1
LEDC2
GND
C
O
1µF
ENABLE
I
2
C Interface
EN
SDA
SCL
20mA
6
VIN
7
C1-
8
C1+
2
I C is a trademark of Philips Corporation. Catalyst Semiconductor is licensed by Philips Corporation to carry the I C bus protocol.
© Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
1
Doc. No. MD-5014 Rev. D
CAT3626
ABSOLUTE MAXIMUM RATINGS
Parameters
VIN, LEDxx voltage
VOUT, C1±, C2± voltage
EN, SDA, SCL voltage
Storage Temperature Range
Junction Temperature Range
Lead Temperature
Ratings
6
7
VIN + 0.7V
-65 to +160
-40 to +150
300
Units
V
V
V
ºC
ºC
ºC
RECOMMENDED OPERATING CONDITIONS
Parameter
VIN
Ambient Temperature Range
LED forward voltage
I
LED
per LED pin
Range
3 to 5.5
-40 to +85
Up to 4.2
0 to 32
Units
V
ºC
V
mA
Typical application circuit with external components is shown on page 1.
ELECTRICAL OPERATING CHARACTERISTICS
V
IN
= 3.6V, EN = High, ambient temperature of 25ºC (over recommended operating conditions unless specified
otherwise)
Symbol
I
Q
I
QSHDN
I
LED
I
LED-ACC
I
LED-DEV
R
OUT
F
OSC
I
SC_MAX
I
IN_MAX
I
EN
V
HI-EN
V
LO-EN
V
HI
V
LO
T
SD
T
HYS
V
UVLO
Parameter
Quiescent Current
Shutdown Current
LED Current Range with 6 LEDs
LED Current Accuracy
LED Channel Matching
Output Resistance (open loop)
Charge Pump Frequency
Output short circuit Current Limit
Input Current Limit
EN Pin
- Input Leakage
- Logic High Level
- Logic Low Level
2
I C SDA, SCL
- High Level Input Voltage
- Low Level Input Voltage
Thermal Shutdown
Thermal Hysteresis
Under-voltage lock out (UVLO)
threshold
V
OUT
< 0.5V
1x mode, V
OUT
> 1V
-1
1.3
0.7 x V
IN
165
20
2
1mA
≤
I
LED
≤
31mA
(I
LED
- I
LEDAVG
) / I
LEDAVG
1x mode, I
OUT
= 120mA
1.5x mode, I
OUT
= 120mA
0.8
Test Conditions
1x mode, all LEDs Off
1x mode, all LEDs On
1.5x mode, all LEDs Off
V
EN
= 0V
Min
Typ
0.5
2.2
3.5
0
±3
±3
0.5
2.8
1
60
300
1
0.4
1.3
Max
Units
mA
mA
mA
µA
mA
%
%
Ω
Ω
MHz
mA
mA
µA
V
V
V
V
ºC
ºC
V
1
32
0
0.3 x V
IN
Doc. No. MD-5014 Rev. D
2
© Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
CAT3626
A.C. CHARACTERISTICS
For 3V
≤
V
IN
≤
5.5V, over full ambient temperature range -40 to +125°C (over recommended operating conditions
unless specified otherwise).
Symbol
f
SCL
t
AA
t
BUF
t
HD:STA
t
LOW
t
HIGH
t
SU:STA
t
HD:DAT
t
SU:DAT
t
R
t
F
t
SU:STO
t
DH
Parameter
Clock Frequency
SCL Low to SDA Data Out and ACK Out
Bus Free Time Before a New Transmission Can Start
Start Condition Hold Time
Clock Low Period
Clock High Period
Start Condition Setup Time (For a Repeated Condition)
Data In Hold Time
Data In Setup Time
SDA and SCL Rise Time
SDA and SCL Fall Time
Stop Condition Setup Time
Data Out Hold Time
0.6
50
1.2
0.6
1.2
0.6
0.6
0
100
0.3
300
Min
Typ
Max
400
0.9
Unit
kHz
µs
µs
µs
µs
µs
µs
ns
ns
µs
ns
µs
ns
t
F
t
LOW
SCL
t
SU:STA
SDA IN
t
AA
t
HD:SDA
t
HIGH
t
LOW
t
R
t
SU:DAT
t
SU:STO
t
HD:DAT
t
DH
t
BUF
SDA OUT
Figure 1. I
2
C Bus Timing Characteristics
© Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
3
Doc. No. MD-5014 Rev. D
CAT3626
TYPICAL CHARACTERISTICS
V
IN
= 3.6V, I
OUT
= 90mA (6 LEDs at 15mA), EN = V
IN
, C
IN
= C
1
= C
2
= C
OUT
= 1µF, T
AMB
= 25ºC, unless otherwise specified.
Efficiency vs. Supply Voltage (6 LEDs)
100
90
EFFICIENCY [%]
EFFICIENCY [%]
Efficiency vs. Total LED Current (6 LEDs)
100
90
80
70
60
50
40
VIN = 3.2V (1.5x mode)
VIN = 4V (1x mode)
1x Mode
15mA per LED
80
70
60
50
40
4.2 4.0 3.8 3.6 3.4 3.2 3.0
SUPPLY VOLTAGE [V]
20mA per LED
1.5x Mode
0
50
100
150
200
TOTAL LED CURRENT [mA]
Quiescent Current vs. Supply Voltage (1x Mode)
QUIESCENT CURRENT [mA]
0.8
0.6
0.4
6 LEDs OFF
0.2
0
3.0
3.2 3.4 3.6 3.8 4.0 4.2
SUPPLY VOLTAGE [V]
Quiescent Current vs. Temperature (1x Mode)
QUIESCENT CURRENT [mA].
0.8
0.6
0.4
0.2
6 LEDs OFF
0.0
-40
0
40
80
TEMPERATURE [°C]
120
Quiescent Current vs. Supply Voltage (1.5x Mode)
QUIESCENT CURRENT [mA].
5
4
3
2
1
0
3.0
3.2 3.4 3.6 3.8 4.0
SUPPLY VOLTAGE [V]
4.2
6 LEDs OFF
Quiescent Current vs. Temperature (1.5x Mode)
QUIESCENT CURRENT [mA].
5
4
3
2
1
6 LEDs OFF
0
-40
0
40
80
TEMPERATURE [°C]
120
Doc. No. MD-5014 Rev. D
4
© Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
CAT3626
TYPICAL CHARACTERISTICS
V
IN
= 3.6V, I
OUT
= 90mA (6 LEDs at 15mA), EN = V
IN
, C
IN
= C
1
= C
2
= C
OUT
= 1µF, T
AMB
= 25ºC, unless otherwise specified.
LED Current Change vs. Supply Voltage
5.0
4.0
3.0
2.0
1.0
0.0
-1.0
-2.0
-3.0
-4.0
-5.0
3.0
LED CURRENT CHANGE [%]
LED Current Change vs. Temperature
5.0
4.0
3.0
2.0
1.0
0.0
-1.0
-2.0
-3.0
-4.0
-5.0
-40
-20 0
20 40 60
TEMPERATURE [°C]
80
LED CURRENT CHANGE [%]
1x Mode
1.5x Mode
3.2 3.4 3.6 3.8 4.0
SUPPLY VOLTAGE [V]
4.2
Switching Frequency vs. Supply Voltage
SWITCHING FREQUENCY [MHz]
1.3
1.2
1.1
1.0
0.9
0.8
0.7
3.0
3.2
3.4
3.6
3.8
SUPPLY VOLTAGE [V]
4.0
Switching Frequency vs. Temperature
SWITCHING FREQUENCY [MHz]
1.3
1.2
1.1
1.0
0.9
0.8
0.7
-40
0
40
80
TEMPERATURE [°C]
120
Output Resistance vs. Supply Voltage (1x Mode)
1.0
OUTPUT RESISTANCE [Ω] .
Output Resistance vs. Supply Voltage(1.5x Mode)
4.0
OUTPUT RESISTANCE [Ω] .
3.5
3.0
2.5
2.0
1.5
1.0
3.0
3.2 3.4 3.6 3.8 4.0
SUPPLY VOLTAGE [V]
4.2
0.8
0.6
0.4
0.2
0.0
3.0
3.2 3.4 3.6 3.8 4.0
SUPPLY VOLTAGE [V]
4.2
© Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
5
Doc. No. MD-5014 Rev. D
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