3-Channel LED Driver in 3 x 3mm Package

CAT3603
3-Channel LED Driver in
3 x 3 mm Package
Description
The CAT3603 is a charge pump LED driver operating in either 1x
(LDO) mode or 1.5x fractional mode regulating current through each
of the 3 LED pins. Operation at a constant switching frequency of
1 MHz allows the use of very small value ceramic capacitors.
The CAT3603 drives 3 white LEDs in parallel and provides tightly
matched regulated current to achieve uniform brightness in LCD
backlighting applications. An external resistor, RSET, controls the
output current level. The device can deliver up to 30 mA over an input
voltage supply range from 3 V to 5.5 V, making it ideal for battery−
powered applications.
LED dimming can be accomplished using several methods; using a
DC voltage to set the RSET pin current, applying a PWM signal on the
EN pin, or adding a switched resistor in parallel with RSET. The EN
input pin allows the device to be placed in power−down mode with
“near−zero” quiescent current.
The device is available in the tiny 12−lead thin DFN 3 mm x 3 mm
package with a max height of 0.8 mm.
Features
•
•
•
•
•
•
•
•
•
•
•
•
•
Drives up to 3 LEDs
Current Setting Resistor
Compatible with Supply Voltage of 3 V to 5.5 V
Power Efficiency up to 91%
Output Current up to 30 mA per LED
Fractional Pump 1x/1.5x
Low Noise Input Ripple
Fixed High Frequency Operation 1 MHz
“Zero” Current Shutdown Mode
Soft Start and Current Limiting
Short Circuit Protection
12−lead TDFN 3 mm x 3 mm Package
This Device is Pb−Free, Halogen Free/BFR Free and RoHS
Compliant
Applications
•
•
•
•
January, 2010 − Rev. 5
TDFN−12
HV2 SUFFIX
CASE 511AN
PIN CONNECTIONS
1
LED1
GND
LED2
C2+
LED3
C2−
RSET
C1−
EN
C1+
VOUT
VIN
(Top View)
MARKING DIAGRAM
HABB
HABB = CAT3603 Device Code
ORDERING INFORMATION
Device
Package
Shipping
CAT3603HV2
TDFN−12
(Pb−Free)
Green*
2,000/Tape & Reel
* Lead Finish Matte−Tin
LCD Display Backlight
Cellular Phones
Digital Still Cameras
Handheld Devices
© Semiconductor Components Industries, LLC, 2010
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Publication Order Number:
CAT3603/D
CAT3603
1 mF
C1+
VIN
C1− C2+
VIN
CIN
3V
to
5.5 V
1 mF
C2−
VOUT
CAT3603
1 mF
OFF ON
COUT
1 mF
EN
LED1
RSET
LED2
20 mA
LED3
GND
23.7 kW
VOUT
Note: Unused LED channels must be connected to VOUT.
Figure 1. Typical Application Circuit
Table 1. ABSOLUTE MAXIMUM RATINGS
Parameter
Rating
Unit
VIN, VOUT, LEDx voltage
−0.3 to 7.0
V
EN voltage
−0.3 to VIN
V
RSET voltage
−0.3 to VIN
V
Junction Temperature Range
−40 to +150
_C
Storage Temperature Range
−65 to +160
_C
300
_C
2,000
V
200
V
Lead Temperature
ESD Rating HBM (Human Body Model)
ESD Rating MM (Machine Model)
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. RECOMMENDED OPERATING CONDITIONS
Parameter
VIN
Ambient Temperature Range
Input, Output, Bucket Capacitors
ILED per LED pin
1. Typical application circuit with external components is shown above.
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Range
Unit
3 to 5.5
V
−40 to +85
_C
1 ±20% typical
mF
0 to 30
mA
CAT3603
Table 3. ELECTRICAL OPERATING CHARACTERISTICS
(VIN = 3.6 V, EN = High, TAMB = 25°C over recommended operating conditions unless otherwise stated.)
Symbol
IQ
Parameter
Quiescent Current
Conditions
Min
VEN = 0 V, shutdown mode
1x Mode, No Load
1.5x Mode, No Load
1.17
Typ
Max
Units
0.1
0.4
2.7
1
1
5
mA
mA
mA
1.2
1.23
V
VRSET
RSET Regulated Voltage
ILED
Programmed LED Current
IRSET = 5 mA
IRSET = 37 mA
IRSET = 78 mA
2.4
15.0
30.0
mA
ILED−ACC
LED Current Accuracy
0.5 mA ≤ ILED ≤ 3 mA
3 mA ≤ ILED ≤ 30 mA
±15
±5
%
ILED−DEV
LED Channel Matching
(ILED – ILEDAVG) / ILEDAVG
±3
%
ROUT
Output Resistance
(Open Loop)
1x Mode
1.5x Mode, IOUT = 100 mA
1.4
6.5
2.5
10
W
fOSC
Charge Pump Frequency
0.8
1.0
1.3
MHz
TDROPOUT
1x to 1.5x Mode Transition
Dropout Delay
0.4
0.6
0.9
ms
1
mA
IEN
Input Leakage Current
On Input EN
VEN
High Detect Threshold
Low Detect Threshold
On Input EN
ISC
Short Circuit Output Current
ILIM
Maximum Input Current
0.8
0.7
1.3
V
0.4
VOUT = GND
30
45
60
mA
VOUT > 1 V
200
400
600
mA
TSD
Thermal Shutdown
150
°C
THYS
Thermal Hysteresis
20
°C
VUVLO
Undervoltage lock out (UVLO) threshold
2
V
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CAT3603
TYPICAL CHARACTERISTICS
(VIN = 3.6 V, IOUT = 60 mA (3 LEDs at 20 mA), C1 = C2 = CIN = COUT = 1 mF, TAMB = 25°C unless otherwise specified.)
100
100
1x Mode
1.5x Mode
90
90
EFFICIENCY (%)
EFFICIENCY (%)
VIN = 4 V (1x Mode)
80
70
20 mA per LED
15 mA per LED
60
50
40
4.2
4.0
3.8
3.6
3.4
3.2
20
40
60
80
LED CURRENT (mA)
Figure 2. Efficiency vs. Input Voltage
(3 LEDs on)
Figure 3. Efficiency vs. Total LED Current
(3 LEDs)
100
0.8
QUIESCENT CURRENT (mA)
QUIESCENT CURRENT (mA)
0
INPUT VOLTAGE (V)
0.4
0.2
LEDs Off
3.0
3.2
3.4
3.6
3.8
4.0
0.6
0.4
0.2
LEDs Off
0
−40
4.2
0
40
80
120
INPUT VOLTAGE (V)
TEMPERATURE (°C)
Figure 4. Quiescent Current vs. Input Voltage
(1x Mode)
Figure 5. Quiescent Current vs. Temperature
(1x Mode)
6.0
QUIESCENT CURRENT (mA)
6.0
QUIESCENT CURRENT (mA)
VIN = 3.2 V (1.5x Mode)
60
40
3.0
0.6
5.0
4.0
3.0
2.0
1.0
0
70
50
0.8
0
80
LEDs Off
3.0
3.2
3.4
3.6
3.8
4.0
5.0
4.0
3.0
2.0
1.0
0
−40
4.2
LEDs Off
0
40
80
120
INPUT VOLTAGE (V)
TEMPERATURE (°C)
Figure 6. Quiescent Current vs. Input Voltage
(1.5x Mode)
Figure 7. Quiescent Current vs. Temperature
(1.5x Mode)
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CAT3603
TYPICAL CHARACTERISTICS
5.0
5.0
4.0
4.0
LED CURRENT CHANGE (%)
LED CURRENT CHANGE (%)
(VIN = 3.6 V, IOUT = 60 mA (3 LEDs at 20 mA), C1 = C2 = CIN = COUT = 1 mF, TAMB = 25°C unless otherwise specified.)
3.0
2.0
1x Mode
1.0
0
1.5x Mode
−1.0
−2.0
−3.0
−4.0
−5.0
3.0
3.2
3.4
3.6
3.8
4.0
4.2
−1.0
−2.0
−3.0
−4.0
−5.0
−40
VIN = 4 V
0
40
80
120
Figure 9. LED Current Change vs.
Temperature
1.3
SWITCHING FREQUENCY (MHz)
SWITCHING FREQUENCY (MHz)
0
Figure 8. LED Current Change vs. Input
Voltage
1.1
1.0
0.9
0.8
3.0
3.2
3.4
3.6
3.8
4.0
1.2
1.1
1.0
0.9
0.8
0.7
−40
4.2
0
40
80
120
INPUT VOLTAGE (V)
TEMPERATURE (°C)
Figure 10. Switching Frequency vs. Input
Voltage
Figure 11. Switching Frequency vs.
Temperature
10
OUTPUT RESISTANCE (W)
4
OUTPUT RESISTANCE (W)
1.0
TEMPERATURE (°C)
1.2
3
2
1
0
2.0
INPUT VOLTAGE (V)
1.3
0.7
3.0
3.0
3.2
3.4
3.6
3.8
4.0
8
6
4
2
4.2
3.0
3.2
3.4
3.6
3.8
4.0
4.2
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
Figure 12. Output Resistance vs. Input Voltage
(1x Mode)
Figure 13. Output Resistance vs. Input Voltage
(1.5x Mode)
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CAT3603
TYPICAL CHARACTERISTICS
(VIN = 3.6 V, IOUT = 60 mA (3 LEDs at 20 mA), C1 = C2 = CIN = COUT = 1 mF, TAMB = 25°C unless otherwise specified.)
VIN
50mV/div
VIN
50mV/div
AC Coupled
AC Coupled
Input
Current
10mA/div
Input
Current
10mA/div
AC Coupled
VOUT
50mV/div
AC Coupled
VOUT
50mV/div
AC Coupled
AC Coupled
500ns/div
500ns/div
Figure 14. Switching Waveforms in 1.5x Mode
Figure 15. Operating Waveforms in 1x Mode
EN
2V/div
EN
2V/div
Input
Current
100mA/
div
Input
Current
100mA/
div
VOUT
5V/div
VOUT
5V/div
500ms/div
500ms/div
Figure 16. Power Up 3 LEDs at 20 mA,
VIN = 3.2 V (1.5x Mode)
Figure 17. Power Up 3 LEDs at 20 mA,
VIN = 4 V (1x Mode)
100
LED CURRENT (mA)
VIN
2V/div
LED
Current
5mA/div
10
VOUT
5V/div
1
10
100
1,000
200ms/div
RSET (kW)
Figure 18. LED Current vs. RSET
Figure 19. Line Transient Response
in 1x Mode
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CAT3603
TYPICAL CHARACTERISTICS
(VIN = 3.6 V, IOUT = 60 mA (3 LEDs at 20 mA), C1 = C2 = CIN = COUT = 1 mF, TAMB = 25°C unless otherwise specified.)
OUTPUT VOLTAGE (V)
5
4
1x Mode
3
2
1
0
0
100
200
300
400
500
OUTPUT CURRENT (mA)
Figure 20. Foldback Current Limit
Table 4. PIN DESCRIPTION
Pin #
Name
Function
1
LED1
LED1 cathode terminal (if not used, connect to VOUT) (Note 2)
2
LED2
LED2 cathode terminal (if not used, connect to VOUT) (Note 2)
3
LED3
LED3 cathode terminal (if not used, connect to VOUT) (Note 2)
4
RSET
The LED output current is set by the current sourced out of the RSET pin
5
EN
6
VOUT
Device enable (active high)
Charge pump output connected to the LED anodes
7
VIN
Supply voltage
8
C1+
Bucket capacitor 1 terminal
9
C1−
Bucket capacitor 1 terminal
10
C2−
Bucket capacitor 2 terminal
11
C2+
Bucket capacitor 2 terminal
12
GND
Ground Reference
TAB
Connect to GND on the PCB
2. LED1, LED2, LED3 pins should not be left floating. They should be connected to the LED cathode, or tied to VOUT pin if not used.
Pin Function
C1+, C1− are connected to each side of the 1 mF ceramic
bucket capacitor C1.
VIN is the supply pin for the charge pump. A small 1 mF
ceramic bypass capacitor is required between the VIN pin
and ground near the device. The operating input voltage
range is from 3.0 V to 5.5 V.
EN is the enable control logic input for all LED channels.
Guaranteed levels of logic high and logic low are set at 1.3 V
and 0.4 V respectively.
RSET pin is regulated at 1.2 V. An external resistor RSET
connected from the RSET pin to GND sets the LED current.
VOUT is the charge pump output that is connected to the
LED anodes. A small 1 mF ceramic bypass capacitor is
required between the VOUT pin and ground near the device.
GND is the ground reference for the charge pump. The pin
must be connected to the ground plane on the PCB.
C2+, C2− are connected to each side of the 1 mF ceramic
bucket capacitor C2.
LED1 to LED3 provide the internal regulated current for
each of the LED cathodes. These pins enter a high
impedance, zero current state whenever the device is placed
in shutdown mode. In applications using less than three
LEDs, all unused channels should be wired directly to
VOUT. This ensures the channel is automatically disabled
dissipating less than 200 mA.
TAB is the exposed pad underneath the package. For best
thermal performance, the tab should be soldered to the PCB
and connected to the ground plane.
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CAT3603
Block Diagram
Figure 21. CAT3603 Functional Block Diagram
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CAT3603
Basic Operation
At power−up, the CAT3603 starts operating in 1x mode
where the output will be approximately equal to the input
supply voltage (minus any internal voltage losses). If the
output voltage is sufficient to regulate all LED currents, the
device remains in 1x operating mode.
If the input voltage falls to a level where the regulated
currents cannot be maintained, the device automatically
switches into 1.5x mode.
In 1.5x mode, the output is approximately equal to 1.5
times the input supply voltage (minus any internal voltage
losses), and high enough to achieve the nominal LED
current.
The above sequence is reinitialized every time the chip is
powered−up or is taken out of shutdown mode (via EN pin).
External Components
The driver requires a total of four external 1 mF ceramic
capacitors: two for decoupling input and output, and two for
the charge pump. Both capacitor types X5R and X7R are
recommended for the LED driver application. In the 1.5x
charge pump mode, the input current ripple is kept very low
by design, and an input bypass capacitor of 1 mF is sufficient.
In 1x mode, the device operating in linear mode does not
introduce switching noise back onto the supply.
Recommended Layout
In 1.5x charge pump mode, the driver switches internally
at a high frequency of 1 MHz. It is recommended to
minimize trace length to all four capacitors. A ground plane
should cover the area under the driver IC as well as the
bypass capacitors. Short connection to ground on capacitors
CIN and COUT can be implemented with the use of multiple
via. A copper area matching the TDFN exposed pad (GND)
must be connected to the ground plane underneath. The use
of multiple via improves the package heat dissipation.
LED Current Setting
The LED current is set by the external resistor RSET
connected between the RSET pin and ground. Table 5 lists
various LED currents and the associated RSET resistor value
for standard 1% precision surface mount resistors.
Table 5. RSET Resistor Selection
LED Current [mA]
RSET [kW]
1
649
2
287
5
102
10
49.9
15
32.4
20
23.7
30
15.4
The unused LED channels must be disabled by connecting
the respective LED pins to VOUT. A disabled channel sinks
only 0.2 mA typical. When the following equation is true on
any channel, the driver turns off the LED channel:
Figure 22. Recommended Layout
VOUT * V LED v 1 V (LED channel OFF)
Note: The CAT3603 is designed to drive LEDs with forward
voltage greater than 1 V and is not compatible with resistive
loads less than 5 kW.
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CAT3603
PACKAGE DIMENSIONS
TDFN12, 3x3
CASE 511AN−01
ISSUE A
D
A
e
b
L
E
E2
PIN#1 ID
PIN#1 INDEX AREA
A1
TOP VIEW
MIN
NOM
MAX
A
0.70
0.75
0.80
A1
0.00
0.02
0.05
A3
0.178
0.203
0.228
b
0.18
0.23
0.30
D
2.90
3.00
3.10
D2
2.30
2.40
2.50
E
2.90
3.00
3.10
E2
1.55
1.70
1.75
A
A3
A1
FRONT VIEW
RECOMMENDED LAND PATTERN
R
e
M
0.45 BSC
L
0.30
0.40
0.50
M
0.25
0.30
0.35
N
0.60
0.70
0.80
P
2.70
3.00
3.10
R
BOTTOM VIEW
SIDE VIEW
SYMBOL
e
D2
N
P
2.25 TYP
E2
Notes:
(1) All dimensions are in millimeters.
(2) Complies with JEDEC MO-229.
D2
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CAT3603
Example of Ordering Information (Notes 3, 4)
3.
4.
5.
6.
7.
Prefix
Device #
Suffix
CAT
3603
HV2
− T2
Company ID
(Optional)
Product Number
3603
Package
HV2: TDFN (Lead−free, Halogen−free)
Tape & Reel (Note 7)
T: Tape & Reel
2: 2,000 / Reel
The device used in the above example is a CAT3603HV2−T2 (TDFN, Tape & Reel, 2,000/Reel).
All packages are RoHS−compliant (Lead−free, Halogen−free).
The standard lead finish is Matte−Tin.
For additional package and temperature options, please contact your nearest ON Semiconductor Sales office.
For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging
Specifications Brochure, BRD8011/D.
ON Semiconductor and
are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice
to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability
arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages.
“Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All
operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. SCILLC does not convey any license under its patent rights
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Order Literature: http://www.onsemi.com/orderlit
For additional information, please contact your local
Sales Representative
CAT3603/D
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