CAT4002A, CAT4004A
Constant Current LED
Driver with 32 Dimming
Levels and Rset
Description
The CAT4002A and CAT4004A provide respectively two and four
matched low dropout current sources to drive LEDs. The CAT400XA
uses an external resistor RSET to set the current in the LED channels.
Each LED channel includes an individual control loop allowing the
device to handle a wide range of LED forward voltages while still
maintaining tight current matching.
The EN/DIM logic inputs supports device enable and a digital
dimming interface for setting the LED channel current with 32 linear
dimming levels.
LEDs can be powered directly from a Lithium−ion battery due to the
low dropout (50 mV at 20 mA) current sinks. The device is available
in the tiny 8−pad UDFN 2 mm x 2 mm package with a max height of
0.55 mm, as well as the 6−lead TSOT−23 and SC−70.
Features
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UDFN−8
HU2G SUFFIX
CASE 517AW
TSOT23−6
TD SUFFIX
CASE 419AF
SC70−6
SD SUFFIX
CASE 419AD
•
•
•
•
•
•
•
•
•
•
2 and 4 LED Current Sinks with Tight Matching
32 Dimming Levels
Low Dropout Driver 50 mV at 20 mA
No Switching Noise
Shutdown Current less than 1
mA
LED Current set by External Resistor
Dimming via 1−wire EZDimt Interface
Thermal Shutdown Protection
6−lead TSOT−23, SC−70, and 8−pad UDFN 2 mm x 2 mm Packages
These Devices are Pb−Free, Halogen Free/BFR Free and are RoHS
Compliant
PIN CONNECTIONS
1
EN/DIM
GND
LED1
LED2
CAT4004A
UDFN−8
1
EN/DIM
GND
VIN
CAT4002A
TSOT23−6
1
LED1
RSET
LED2
VIN
RSET
LED4
LED3
Applications
•
LCD Display Backlight
•
Cellular Phones
V
IN
2.4 V
to
5.5 V
C
IN
1
mF
•
Digital Still Cameras
•
Handheld Devices
20 mA
EN/DIM
RSET
LED1
GND
LED2
CAT4002A
SC70−6
(Top Views)
LED1 LED2 LED3 LED4
VIN
One wire
programming
RSET
3.74 kW
EN/DIM
RSET
GND
CAT4004A
VIN
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 11 of this data sheet.
Figure 1. Typical Application Circuit
©
Semiconductor Components Industries, LLC, 2011
June, 2011
−
Rev. 2
1
Publication Order Number:
CAT4002A/D
CAT4002A, CAT4004A
MARKING DIAGRAMS
BGA
YM
VLYM
VJA
UDFN8 (2 x 2 mm)
BG
A
Y
M
= CAT4004A Device Code
= Assembly Location Code
= Production Year (last digit)
= Production Month: 1
−
9, A, B, C
VL
Y
M
TSOT23−6
= CAT4002A Device Code
= Production Year (last digit)
= Production Month: 1
−
9, A, B, C
VJ
A
SC70−6
= CAT4002A Device Code
= Assembly Location Code
Table 1. ABSOLUTE MAXIMUM RATINGS
Parameter
VIN, LEDx, RSET
EN/DIM Voltage
Storage Temperature Range
Junction Temperature Range
Lead Temperature
Rating
6
6
−65
to +160
−40
to +125
300
Unit
V
V
°C
°C
°C
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.
Table 2. ELECTRICAL OPERATING CHARACTERISTICS
(Min and Max values are over recommended operating conditions
unless specified otherwise. Typical values are at V
IN
= 4.0 V, EN/DIM = High, and T
AMB
= 25°C.)
Symbol
I
Q
I
QSHDN
I
LED
I
LED−ACC
I
LED−DEV
V
RSET
V
DOUT
Quiescent Current
Shutdown Current
LED Current Setting
Name
Conditions
No load, RSET = Float
No load, RSET = 4.8 kW
V
EN/DIM
= 0 V
RSET = 3.0 kW
RSET = 4.99 kW
LED Current Accuracy
LED Channel Matching (Note 1)
1 mA
≤
I
LED
≤
40 mA
I
LED
*
I
LEDAVG
I
LEDAVG
−5
25
15
±1
±1
0.6
50
25
200
1.3
0.4
150
20
2.0
+5
%
%
Min
Typ
0.2
0.5
1
Max
Units
mA
mA
mA
RSET pin regulated voltage
Dropout Voltage
(90% of nominal LED current)
EN/DIM Pin
−
Internal pull−down resistor
−
Logic High Level
−
Logic Low Level
Thermal Shutdown
Thermal Hysteresis
Undervoltage lockout (UVLO) threshold
I
LED
= 20 mA
I
LED
= 1 mA
0.57
0.63
V
mV
R
EN/DIM
V
HI
V
LO
T
SD
T
HYS
V
UVLO
kW
V
V
°C
°C
V
1. For CAT4004A, I
LEDAVG
= (I
LED,CH1
+ I
LED,CH2
+ I
LED,CH3
+ I
LED,CH4
) / 4
For CAT4002A, I
LEDAVG
= (I
LED,CH1
+ I
LED,CH2
) / 2
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2
CAT4002A, CAT4004A
Table 3. RECOMMENDED OPERATING CONDITIONS
Parameter
V
IN
Ambient Temperature Range
I
LED
per LED pin
NOTE:
Typical application circuit with external components is shown on page 1.
Rating
2.4 to 5.5
−40
to +85
0 to 40
Unit
V
°C
mA
Table 4. RECOMMENDED EN/DIM TIMING
(For 2.4 V
≤
V
IN
≤
5.5 V, over full ambient temperature range
−40°C
to +85°C.)
Symbol
T
LO
T
HI
T
LED
T
PWRDWN
Name
EN/DIM program low time
EN/DIM program high time
LED current settling time
EN/DIM low time to shutdown
T
HI
EN/DIM
T
LO
T
LED
100%
LED
Current
Shutdown
97% 94%
32 Levels
3%
0%
100%
T
PWRDWN
Conditions
Min
0.2
0.2
10
3
5
Typ
Max
100
Units
ms
ms
ms
ms
Shutdown
Figure 2. CAT400XA EN/DIM Dimming Timing Diagram
LED Current Setting
Table 5. RSET RESISTOR AND LED CURRENT
Full Scale
LED Current [mA]
2
5
10
15
20
25
30
40
RSET [kW]
40.2
15.4
7.68
4.99
3.74
3.00
2.49
1.87
On the CAT400XA, the full scale LED current is set by the
external resistor connected between the RSET pin and
ground. Table 5 lists standard resistor values for several
LED current settings.
When the EN/DIM is initially taken high, the CAT400XA
becomes enabled and the LED channel current is set to the
full scale current according to the resistor RSET.
LED current
≅
125 x V
RSET
/ RSET
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CAT4002A, CAT4004A
TYPICAL PERFORMANCE CHARACTERISTICS
(CAT4002A, V
IN
= 4 V, V
F
= 3.3 V, I
OUT
= 50 mA (2 LEDs at 25 mA), C
IN
= 1
mF,
T
AMB
= 25°C unless otherwise specified.)
2.0
QUIESCENT CURRENT (mA)
1.6
1.2
0.8
0.4
0
QUIESCENT CURRENT (mA)
0
20
RSET (kW)
40
60
1.4
1.2
1.0
0.8
0.6
2.5
3.0
3.5
4.0
4.5
5.0
5.5
INPUT VOLTAGE (V)
Figure 3. Quiescent Current vs. RSET Input
Voltage
1.0
LED CURRENT CHANGE (%)
0.6
0.4
0.2
0
−0.2
−0.4
−0.6
−0.8
−1.0
LED CURRENT CHANGE (%)
0.8
10
8
6
4
2
0
−2
−4
−6
Figure 4. Quiescent Current vs. Input Voltage
(Full Load)
2.5
3.0
3.5
4.0
4.5
5.0
5.5
−8
−10
−40
0
40
TEMPERATURE (°C)
80
120
INPUT VOLTAGE (V)
Figure 5. LED Current Change vs. Input
Voltage
1.4
ENABLE HIGH THRESHOLD (V)
1.2
1.0
0.8
0.6
0.4
25°C
−40°C
LED CURRENT (mA)
40
Figure 6. LED Current Change vs.
Temperature
30
20
80°C
10
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
0
1
10
RSET (kW)
100
INPUT VOLTAGE (V)
Figure 7. EN/DIM High Threshold vs. Input
Voltage
Figure 8. LED Current vs. RSET Resistor
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CAT4002A, CAT4004A
TYPICAL PERFORMANCE CHARACTERISTICS
(CAT4002A, V
IN
= 4 V, V
F
= 3.3 V, I
OUT
= 50 mA (2 LEDs at 25 mA), C
IN
= 1
mF,
T
AMB
= 25°C unless otherwise specified.)
30
25
LED CURRENT (mA)
20
15
10
5
0
1 mA
0
50
100
150
200
250
300
25 mA
90
EFFICIENCY (%)
80
70
60
50
100
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
LED PIN VOLTAGE (mV)
INPUT VOLTAGE (V)
Figure 9. Dropout Characteristics
Figure 10. Efficiency vs. Input Voltage
Figure 11. Power Up Waveform
Figure 12. Power Down Waveform
Figure 13. Line Transient Waveform
Figure 14. Dimming Levels
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