CAT3643
3-Channel Ultra High Efficiency Quad-Mode™
LED Driver
FEATURES
High efficiency 1.33x charge pump
Quad-mode charge pump: 1x, 1.33x, 1.5x, 2x
Drives up to 3 LEDs at 32mA each
1-wire EZDim™ LED current programming
Power efficiency up to 92%
Low noise input ripple in all modes
“Zero” current shutdown mode
Soft start and current limiting
Short circuit protection
Thermal shutdown protection
Tiny 12-pad XQFN, 12-pad TDFN and 16-pad
TQFN packages
DESCRIPTION
The CAT3643 is a high efficiency Quad-Mode
TM
fractional charge pump that can drive up to three
LEDs programmable by a one wire digital interface.
The inclusion of a 1.33x fractional charge pump mode
increases device efficiency by up to 10% over
traditional 1.5x charge pumps with no added external
capacitors.
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 2.4V to 5.5V.
The EN/DIM logic input functions as a chip enable and
a digital dimming interface for current setting of all
LEDs. Six different current ratios are available via the
interface.
The device is available in the tiny 12-pad XQFN 2.5 x
2.5mm with max height of 0.4mm or in 16-pad TQFN
or 12-pad TDFN 3mm x 3mm package with a max
height of 0.8mm.
TM
Catalyst Semiconductor’s Quad-Mode 1.33x charge
pump switching architecture is patented.
APPLICATION
LCD Display Backlight
Cellular Phones
Digital Still Cameras
Handheld Devices
ORDERING INFORMATION
Part Number
CAT3643HV2-T2
CAT3643HV2-GT2
CAT3643HV3-T2
CAT3643HV3-GT2
CAT3643HL1-T2
Package
TDFN-12 3 x 3
(1)
TDFN-12 3 x 3
(2)
Marking
HABF
HABG
JAAE
JAAF
LB
V
IN
2.4V
to
5.5V
C
IN
1µF
EN/DIM
RSET
4.02kΩ
GND
C1+
V
IN
TQFN-16 3 x 3
(1)
TQFN-16 3 x 3
(2)
TYPICAL APPLICATION CIRCUIT
1µF
1µF
XQFN-12 2.5 x 2.5
(1)
Notes:
(1) Matte-Tin Plated Finish (RoHS-compliant)
(2)
(3)
NiPdAu Plated Finish (RoHS-compliant)
Quantity per reel is 2000
C1- C2+
C2-
V
OUT
V
OUT
C
OUT
1µF
CAT3643
LED1
LED2
LED3
For Ordering Information details, see page 16.
1-Wire
EZDim
TM
Programming
20mA
© Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
1
Doc. No. MD-5022 Rev. E
CAT3643
PIN CONFIGURATION
TDFN 12-Pad 3 x 3mm
(Top View)
TQFN 16-Pad 3 x 3mm
(Top View)
LED1
GND
NC
NC
LED1
LED2
LED3
RSET
EN/DIM
VOUT
1
2
3
4
5
6
12 GND
11 C2+
10 C2-
9 C1-
8 C1+
7 VIN
16
LED2
LED3
NC
RSET
1
2
3
4
5
EN/DIM
15
14
13
12 C2-
11 C2+
10 C1-
9 C1+
6
VOUT
7
NC
8
VIN
XQFN 12-Pad 2.5 x 2.5mm
(Top View)
12
C2-
GND
LED1
1
2
3
4
LED2
C2+
C1+
11
C1-
10
9 VIN
8 VOUT
7 EN/DIM
5
LED3
6
RSET
The CAT3643 is offered in three different packages.
The 12-pad TDFN 3mm x 3mm with a max height of
0.8mm is pin-compatible to the Catalyst CAT3603
LED driver. The 12-pad XQFN provides the smallest
footprint with a package size of 2.5mm x 2.5mm and
0.4mm max height. The 16-pad TQFN 3mm x 3mm
with max height of 0.8mm is also offered.
Doc. No. MD-5022 Rev. E
2
© Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
CAT3643
ABSOLUTE MAXIMUM RATINGS
Parameter
V
IN
, LEDx, C1±, C2±, EN/DIM, RSET voltage
V
OUT
voltage
Storage Temperature Range
Junction Temperature Range
RECOMMENDED OPERATING CONDITIONS
Parameter
Rating
V
IN
2.5 to 5.5
Ambient Temperature Range
-40 to +85
I
LED
per LED pin
up to 30
LED Forward Voltage Range
1.3 to 4.3
Typical application circuit with external components is shown on page 1.
Unit
V
°C
mA
V
Rating
6
7
-65 to +160
-40 to +150
Unit
V
V
°C
°C
ELECTRICAL OPERATING CHARACTERISTICS
(over recommended operating conditions unless specified otherwise) V
IN
= 3.6V, EN = High, T
AMB
= 25°C
Symbol
I
Q
I
QSHDN
I
LED-ACC
I
LED-DEV
V
RSET
R
OUT
Name
Quiescent Current
Shutdown Current
LED Current Accuracy
LED Channel Matching
RSET Regulated Voltage
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
EN
= 0V
(I
LEDAVG
– I
NOMINAL
) / I
NOMINAL
RSET = 5kΩ
(I
LED
- I
LEDAVG
) / I
LEDAVG
0.58
1x mode
1.33x mode, V
IN
= 3V
1.5x mode, V
IN
= 2.7V
2x mode, V
IN
= 2.4V
1.33x and 2x mode
1.5x mode
V
OUT
< 0.5V
V
OUT
> 1V
0.8
1
Min
Typ
1.0
1.7
2.2
2.4
1
±2
±1.5
0.6
0.8
5
5
10
1
1.3
50
250
130
400
500
100
1.3
0.4
150
20
1.8
1.3
1.6
0.62
Max
Units
mA
mA
mA
mA
µA
%
%
V
Ω
Ω
Ω
Ω
MHz
MHz
mA
mA
mV
mV
µs
kΩ
V
V
°C
°C
V
F
OSC
I
SC_MAX
I
IN_MAX
LED
TH
V
HYS
T
DF
R
EN/DIM
V
HI
V
LO
T
SD
T
HYS
V
UVLO
Charge Pump Frequency
Output short circuit Current Limit
Input Current Limit
1x to 1.33x or 1.33x to 1.5x or 1.5x to 2x
Transition Thresholds at any LED pin
1x Mode Transition Hysteresis
Transition Filter Delay
EN/DIM Pin
•
Internal Pull-down Resistor
•
Logic High Level
•
Logic Low Level
Thermal Shutdown
Thermal Hysteresis
Undervoltage lockout (UVLO) threshold
1.6
2.0
© Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
3
Doc. No. MD-5022 Rev. E
CAT3643
RECOMMENDED EN/DIM TIMING
For 2.4V
≤
V
IN
≤
5.5V, over full ambient temperature range -40ºC to +85ºC.
Symbol
T
SETUP
T
LO
T
HI
T
PWRDWN
T
LED
Name
EN/DIM setup from shutdown
EN/DIM program low time
EN/DIM program high time
EN/DIM low time to shutdown
LED current settling time
Conditions
Min
10
0.2
0.2
1.5
40
100
Typ
Max
Units
μs
μs
μs
ms
μs
T
SETUP
T
HI
T
PWRDWN
EN/DIM
T
LED
100%
50%
LED
Current
Shutdown
25%
T
LO
100%
12.5% 6.25%
3.12%
Shutdown
Figure 1. EN/DIM Digital Dimming Timing Diagram
LED Current Setting
The nominal LED current is set by the external
resistor connected between the RSET pin and
ground. Table 1 lists standard resistor values for
several LED current settings.
LED Current (mA)
2
5
10
15
20
25
30
RSET (kΩ)
40.0
15.8
7.87
5.23
4.02
3.16
2.67
Table 1. Resistor RSET and LED Current
Doc. No. MD-5022 Rev. E
4
© Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
CAT3643
TYPICAL PERFORMANCE CHARACTERISTICS
V
IN
= 3.6V, I
OUT
= 60mA (3 LEDs at 20mA), C
IN
= C
OUT
= C
1
= C
2
= 1μF, T
AMB
= 25°C unless otherwise specified.
Efficiency vs. Input Voltage
100
90
EFFICIENCY [%]
1x
80
70
60
50
40
4.5
4.0
3.5
3.0
2.5
INPUT VOLTAGE [V]
2.0
2x
V
F
= 3.3V
1.33x
1.5x
EFFICIENCY [%]
100
90
80
70
60
50
40
4.2
4.0 3.8 3.6 3.4 3.2
INPUT VOLTAGE [V]
3.0
Efficiency vs. Li-Ion Voltage
V
F
= 3.3V
1x
1.33x
Quiescent Current vs. Input Voltage
4.0
QUIESCENT CURRENT [mA]
QUIESCENT CURRENT [mA]
Quiescent Current vs. Temperature
4.0
V
F
= 3.3V
3.0
2.0
1.0
LEDs Off
0.0
5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0
INPUT VOLTAGE [V]
2x
3.0
1.5x
2.0
1.33x
1x
1.0
0.0
-40
0
40
80
TEMPERATURE [°C]
120
LED Current Change vs. Input Voltage
10
8
6
4
2
0
-2
-4
-6
-8
-10
LED CURRENT VARIATION [%] .
LED CURRENT VARIATION [%] .
LED Current Change vs. Temperature
10
8
6
4
2
0
-2
-4
-6
-8
-10
-40
0
40
80
TEMPERATURE [°C]
120
V
F
= 3.3V
V
F
= 3.3V
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
INPUT VOLTAGE [V]
© Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
5
Doc. No. MD-5022 Rev. E
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