CAT3606
6-Channel Low Noise
Charge Pump White LED
Driver
Description
The CAT3606 controls up to four LEDs for the main display and
two LEDs for the sub-display in cellular phones. The device is capable
of operating in either 1x (LDO) mode or 1.5x charge pump mode. All
LED pin currents are regulated and tightly matched to achieve
uniformity of brightness across the LCD backlight. An external
resistor (R
SET
) sets the nominal output current.
The device can deliver as much as 20 mA per channel during low
voltage operation (3 V), and 30 mA per channel during nominal
operation (3.3 V). A constant high-frequency switching scheme
(1 MHz) provides low noise and allows the use of very small value
ceramic capacitors.
A “zero” quiescent current mode can be achieved via the chip enable
pin EN. The Main and Sub LEDs each have their own dedicated
ON/OFF control pins ENM, ENS. Dimming can be achieved using
either a DC voltage to control the R
SET
pin current, or by applying a
PWM signal on the ENM and ENS pins.
The device is available in a 16−pad TQFN package with a max
height of 0.8 mm.
Features
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TQFN−16
HV4 SUFFIX
CASE 510AE
PIN CONNECTIONS
(Note 1)
LED5
LED4
LED3
LED2
LED6
EN
ENM
ENS
1
LED1
GND
C2+
C2−
C1−
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Drives up to 4 Main LEDs and 2 Sub LEDs
Separate Control for Main and Sub LEDs
Compatible with Supply Voltage of 3 V to 5.5 V
Power Efficiency up to 90%
Output Current up to 30 mA per LED
High−frequency Operation at 1 MHz
2 Modes of Operation 1x and 1.5x
White LED Detect Circuitry on All Channels
Shutdown Current less than 1
mA
Small Ceramic Capacitors
Soft Start and Current Limiting
Short Circuit Protection
16−pad TQFN Package, 0.8 mm Max Height
These Devices are Pb−Free, Halogen Free/BFR Free and are RoHS
Compliant
Cell Phone Main and Sub−display Backlight
Navigation
PDAs
Digital Cameras
RSET
(4 x 4 mm) (Top View)
MARKING DIAGRAMS
G366
CDBB
G366 = CAT3606HV4−T2
CDBB = CAT3606HV4−GT2
ORDERING INFORMATION
Device
CAT3606HV4−T2
CAT3606HV4−GT2
Package
TQFN−16
(Note 2)
TQFN−16
(Note 3)
Shipping
2,000/
Tape & Reel
Applications
•
•
•
•
1. The “exposed pad” under the package must be
connected to the ground plane on the PCB.
2. Matte−Tin Plated Finish (RoHS−compliant).
3. NiPdAu Plated Finish (RoHS−compliant).
VOUT
©
Semiconductor Components Industries, LLC, 2010
January, 2010
−
Rev. 3
1
Publication Order Number:
CAT3606/D
C1+
VIN
CAT3606
1
mF
C1+
VIN
C
IN
1
mF
ON/OFF
ENABLE
LED1−4
ENABLE
LED5−6
RSET
24 kW
EN
ENM
ENS
RSET
GND
CAT3606
LED1
LED2
LED3
LED4
LED5
LED6
20 mA
1
mF
Li−Ion
Battery +
−
C1− C2+ C2−
VOUT
Main Display
Sub Display
C
OUT
1
mF
Figure 1. Typical Application Circuit
Table 1. PIN DESCRIPTION
Pin #
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
PAD
Name
LED6
EN
ENM
ENS
RSET
VOUT
VIN
C1+
C1
C2
C2+
LED1
LED2
LED3
LED4
LED5
GND
LED6 cathode terminal
Enable/shutdown input, active high
Enable “main” input for LED1 to LED4, active low
Enable “sub” input for LED5 and LED6, active low
The LED output current is set by the current sourced out of the RSET pin
Charge pump output connected to the LED anodes
Supply voltage
Bucket capacitor 1 terminal
Bucket capacitor 1 terminal
Bucket capacitor 2 terminal
Bucket capacitor 2 terminal
LED 1 cathode terminal
LED 2 cathode terminal
LED 3 cathode terminal
LED 4 cathode terminal
LED 5 cathode terminal
Ground reference
Function
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2
CAT3606
Table 2. ABSOLUTE MAXIMUM RATINGS
Parameter
VIN, VOUT, LEDx voltage
EN, ENM, ENS voltage
RSET voltage
RSET current
Ambient Temperature Range
Storage Temperature Range
Lead Temperature
ESD Rating HBM (Human Body Model)
ESD Rating MM (Machine Model) (Note 4)
Rating
−0.3
to 7.0
−0.3
to VIN
−0.3
to VIN
±1
−40
to +85
−65
to +160
300
2,000
200
Unit
V
V
V
mA
_C
_C
_C
V
V
Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the
Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect
device reliability.
4. Machine model is with 200 pF capacitor discharged directly into each pin.
Table 3. RECOMMENDED OPERATING CONDITIONS
Parameter
VIN
Ambient Temperature Range
Input/Output/Bucket Capacitors
I
LED
per LED pin
I
OUT
Total Output Current
Range
3.0 to 5.5
−40
to +85
1
±20%
Typical
0 to 30
0 to 150
Unit
V
_C
mF
mA
mA
Table 4. ELECTRICAL OPERATING CHARACTERISTICS
Symbol
I
Q
Parameter
Quiescent Current
(
Limits over recommended operating conditions unless specified otherwise. Typical values at T
A
= 25°C, V
IN
= 3.5 V, I
RSET
= 5
mA.)
Conditions
V
EN
= 0 V
1x Mode, No Load
1.5x Mode, No Load
1.17
I
RSET
= 5
mA
I
RSET
= 37
mA
I
RSET
= 78
mA
3.3
≤
VIN
≤
4.5 V
3.0
≤
VIN
≤
4.5 V
3.3
≤
VIN
≤
4.5 V
0.5 mA
≤
I
LED
≤
3 mA
3 mA
≤
I
LED
≤
30 mA
(I
LED
– I
LEDAVG
) / I
LEDAVG
1x Mode,
1.5x Mode, I
OUT
= 100 mA
0.8
0.4
On Inputs EN, ENM, ENS
On Inputs EN, ENM, ENS
0.4
VOUT = GND
VOUT > 1 V
30
200
0.8
0.7
45
400
±15
±5
±3
1.4
6.5
1.0
0.6
2.5
10
1.3
0.9
1
1.3
60
600
Min
Typ
0.1
0.3
2.6
1.2
2.4
15.0
30.0
30
20
30
Max
1
1
5
1.23
Unit
mA
mA
mA
V
mA
V
RSET
I
LED
RSET Regulated Voltage
Programmed LED Current
I
LED
I
LED
I
LED−ACC
I
LED−DEV
R
OUT
f
OSC
T
DROPOUT
I
EN−CTR
V
EN−CTR
I
SC
I
LIM
LED Current Range with 6 LEDs
LED Current Range with 4 LEDs
LED Current Accuracy
LED Channel Matching
Output Resistance
(Open Loop)
Charge Pump Frequency
1x to 1.5x Mode Transition Dropout Delay
Input Leakage Current
High Detect Threshold
Low Detect Threshold
Input Current Limit
Maximum Input Current
mA
mA
%
%
W
MHz
ms
mA
V
mA
mA
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CAT3606
Block Diagram
1
mF
C1−
C1+ C2−
1
mF
C2+
VIN
Battery
V
IN
3 V to 4.2 V
C
IN
1
mF
1x mode (LDO)
1.5x Charge Pump
VOUT
C
OUT
1
mF
1 MHz
Oscillator
EN
Mode Control
LED1
LED2
LED3
LED4
LED5
20 mA
1.2 V Ref
RSET
R
SET
24 kW
ENM
ENS
Current
Setting
LED Output
Select
GND
Main
Sub
LED6
6 Current
Sink Regulators
Figure 2. CAT3606 Functional Block Diagram
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4
CAT3606
Basic Operation
At power-up, the CAT3606 starts operation in 1x mode. If
it is able to drive the programmed LED current, it continues
in 1x mode. If the battery voltage drops to a level where the
LED current cannot be met, the driver automatically
switches into 1.5x mode, to boost the output voltage high
enough to achieve the nominal LED current.
The above sequence is reinitialized each and every time
the chip is powered up or is taken out of shutdown mode (via
EN pin). The use of the Main and Sub display enable pins
(ENM or ENS) does not affect the mode of operation.
LED Current Setting
The enable lines ENM and ENS allow to turn On or Off
a group of LEDs as shown in Table 6.
Table 6. LED Selection
Control Lines
EN
0
1
1
1
1
ENM
X
1
0
1
0
ENS
X
1
1
0
0
LED Outputs
Main
LED1
−
LED4
–
–
ON
−
ON
Sub
LED5
−
LED6
–
–
−
ON
ON
The LED current is set by the external resistor R
SET
connected between the RSET pin and ground. Table 5 lists
various LED currents and the associated R
SET
resistor value
for standard 1% precision surface mount resistors.
Table 5. RSET Resistor Selection
LED Current (mA)
1
2
5
10
15
20
30
R
SET
(kW)
649
287
102
49.9
32.4
23.7
15.4
NOTES: 1 = logic high (or VIN)
0 = logic low (or GND)
– = LED output OFF
X = don’t care
The unused LED channels can also be turned off by
connecting the respective LED pins to VOUT. In which
case, the corresponding LED driver is disabled and the
typical LED sink current is only about 0.2 mA. When the
following equation is true on any channel, the driver turns
off the LED channel:
VOUT
*
V
LED
v
1 V (LED channel OFF)
Note:
The CAT3606 is designed to drive LEDs with forward
voltage greater than 1 V and is not compatible with resistive
loads.
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5
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