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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
VIN 2.4 V to 5.5 V CIN 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
(c) Semiconductor Components Industries, LLC, 2010
July, 2010 - Rev. 0
1
Publication Order Number: CAT4002A/D
CAT4002A, CAT4004A
MARKING DIAGRAMS
BMA XXX YM UDFN8 (2 x 2 mm) BM = CAT4004A Device Code A = Assembly Location Code XXX = Last Three Digits of Assembly Lot Number Y = Production Year (last digit) M = Production Month: 1 - 9, A, B, C VL Y M
VLYM
VJA
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 VIN = 4.0 V, EN/DIM = High, and TAMB = 25C.)
Symbol IQ IQSHDN ILED ILED-ACC ILED-DEV VRSET VDOUT Quiescent Current Shutdown Current LED Current Setting Name Conditions No load, RSET = Float No load, RSET = 4.8 kW VEN/DIM = 0 V RSET = 3.0 kW RSET = 4.99 kW LED Current Accuracy LED Channel Matching (Note 1) 1 mA ILED 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 ILED = 20 mA ILED = 1 mA
0.57
0.63
V mV
REN/DIM VHI VLO TSD THYS VUVLO
kW V V C C V
1. For CAT4004A, ILEDAVG = (ILED,CH1 + ILED,CH2 + ILED,CH3 + ILED,CH4) / 4 For CAT4002A, ILEDAVG = (ILED,CH1 + ILED,CH2) / 2
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CAT4002A, CAT4004A
Table 3. RECOMMENDED OPERATING CONDITIONS
Parameter VIN Ambient Temperature Range ILED 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 VIN 5.5 V, over full ambient temperature range -40C to +85C.)
Symbol TLO THI TLED TPWRDWN Name EN/DIM program low time EN/DIM program high time LED current settling time EN/DIM low time to shutdown THI EN/DIM TLO TLED 100% LED Current Shutdown 97% 94% 32 Levels 3% 0% 100% TPWRDWN 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 VRSET / RSET
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CAT4002A, CAT4004A
TYPICAL PERFORMANCE CHARACTERISTICS
(CAT4002A, VIN = 4 V, VF = 3.3 V, IOUT = 50 mA (2 LEDs at 25 mA), CIN = 1 mF, TAMB = 25C unless otherwise specified.) 2.0 QUIESCENT CURRENT (mA) 1.6 1.2 0.8 0.4 0 QUIESCENT CURRENT (mA) 1.4
1.2
1.0
0.8
0
20 RSET (kW)
40
60
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 25C -40C LED CURRENT (mA) 40
Figure 6. LED Current Change vs. Temperature
30
20
80C
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, VIN = 4 V, VF = 3.3 V, IOUT = 50 mA (2 LEDs at 25 mA), CIN = 1 mF, TAMB = 25C 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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CAT4002A, CAT4004A
Table 6. PIN DESCRIPTIONS
Name EN/DIM GND LED1 LED2 LED3 LED4 RSET VIN TAB Device enable (active high) and dimming control Ground reference LED1 cathode terminal LED2 cathode terminal LED3 cathode terminal (CAT4004A only) LED4 cathode terminal (CAT4004A only) Connect external RSET resistor to set the LED current Device supply input, connect to battery or supply Connect to GND on the PCB (CAT4004A only) Function
Pin Function
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 2.5 V to 5.5 V. Whenever the input supply falls below the under-voltage threshold (2.0 V), all the LED channels are disabled and the device enters shutdown mode. EN/DIM is the enable and one wire dimming input for all LED channels. Levels of logic high and logic low are set at 1.3 V and 0.4 V respectively. When EN/DIM is initially taken high, the CAT400XA becomes enabled and the LED channel current is set to the full scale according to the resistor RSET. To place the device into "zero current" shutdown mode, the EN/DIM pin must be held low for 3 ms typical.
Block Diagram
VIN
LED1 to LED4 provide the internal regulated current for each of the LED cathodes. There pins enter a high impedance zero current state whenver the device is placed in shutdown mode. RSET is connected to the resistor (RSET) to set the full scale current for the LEDs. The voltage at this pin is regulated to 0.6 V. The ground side of the external resistor should be star connected back to the GND of the PCB. In shutdown mode, the RSET input becomes high impedance. GND is the ground reference for the device. The pin must be connected to the ground plane on the PCB. TAB (CAT4004A only) 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.
LED1
LED2
LED3
VIN
Undervoltage Lockout Reference Voltage
RSET
Current Setting DAC
EN/DIM
Serial Interface 100 kW
Register
4 Current Sink Regulators
GND
Figure 15. CAT4004A Functional Block Diagram
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LED4
CAT4002A, CAT4004A
Basic Operation
The CAT400XA uses tightly matched current sinks to accurately regulate LED current in each channel proportional to the current sourced from the RSET pin. There are 32 different settings for LED brightness that can be programmed through the EN/DIM pin. Tight current regulation for all channels is possible over a wide range of input and LED voltages due to independent current sensing circuitry on each channel. Each LED channel needs a minimum of 50 mV headroom to sink a constant regulated current of 20 mA. If the input supply falls below 2.0 V typical, the under-voltage lockout circuit disables all LED channels and resets the circuit to default values. Any unused LED channels should be left open.
LED Current Selection
Table 7. DIMMING LEVELS
Full Scale (Current in %) 100 97 94 90 87 84 81 77 74 71 68 65 61 58 55 52 48 45 42 39 35 32 29 26 23 19 16 13 10 6 3 0 100 Dimming Pulses [n] 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
After power-up, the LED current is set by the external resistor (RSET) value and the number of pulses (n) on the EN/DIM input as follows:
LED current + 125 0.6 V R SET 31 * n 31
The full scale current is calculated from the above formula with n equal to zero. The EN/DIM pin has two primary functions. One function enables and disables the device. The other function is LED current dimming with 32 different levels by pulsing the input signal, as shown on Figure 16. On each consecutive pulse rising edge, the LED current is decreased by about 3.2% (1/31th of the full scale value). After 30 pulses, the LED current is 3.2% of the full scale current. On the 31st pulse, the current drops to zero, and then goes back to full scale on the following pulse. Each pulse width should be between 200 ns and 100 ms. Pulses faster than the minimum TLO may be ignored and filtered by the device. Pulses longer than the maximum TLO may shutdown the device. By pulsing the EN/DIM signal at high frequency, the LED current can quickly be set to zero. The LED driver enters a "zero current" shutdown mode if EN/DIM is held low for 3 ms typical. The dimming level is set by the number of pulses on the EN/DIM after the power-up, as shown in Table 7.
THI EN/DIM TLO TLED 100% LED Current 97% 94% 32 Levels 3%
TPWRDWN 100% Shutdown
Shutdown
0%
Figure 16. EN/DIM Digital Dimming Timing Diagram
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CAT4002A, CAT4004A
PACKAGE DIMENSIONS
UDFN8, 2x2 CASE 517AW-01 ISSUE O
D A D2 DETAIL A
E
E2
PIN #1 IDENTIFICATION A1 PIN #1 INDEX AREA TOP VIEW SIDE VIEW BOTTOM VIEW
SYMBOL A A1 b D D2 E E2 e L
MIN 0.45 0.00 0.18 1.90 1.50 1.90 0.80 0.20
NOM 0.50 0.02 0.25 2.00 1.60 2.00 0.90 0.50 BSC 0.30
MAX 0.55 0.05 0.30 2.10 1.70 2.10 1.00 0.45 DETAIL A L e b
Notes: (1) All dimensions are in millimeters. (2) Complies with JEDEC MO-229.
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CAT4002A, CAT4004A
PACKAGE DIMENSIONS
SC-70, 6 Lead, 1.25x2 CASE 419AD-01 ISSUE O
SYMBOL D e e A A1 A2 b c E1 E D E E1 e L L1 TOP VIEW L2 0.26 MIN 0.80 0.00 0.80 0.15 0.10 1.80 1.80 1.15 2.00 2.10 1.25 0.65 BSC 0.36 0.42 REF 0.15 BSC 0.46 NOM MAX 1.10 0.10 1.00 0.30 0.18 2.20 2.40 1.35
1
0 4
8 10
q1
A2 A q L L1
q1
b
A1
c END VIEW
L2
SIDE VIEW Notes: (1) All dimensions are in millimeters. Angles in degrees. (2) Complies with JEDEC MO-203.
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CAT4002A, CAT4004A
PACKAGE DIMENSIONS
TSOT-23, 6 LEAD CASE 419AF-01 ISSUE O SYMBOL
A A1 A2 b c D E1 E E E1 e L L1 L2 0.30 0.01 0.80 0.30 0.12 0.15 2.90 BSC 2.80 BSC 1.60 BSC 0.95 TYP 0.40 0.60 REF 0.25 BSC 0.50 0.05 0.87
D e
MIN
NOM
MAX
1.00 0.10 0.90 0.45 0.20
TOP VIEW
0
8
A2 A
q
b
A1 L1
L
c
L2
SIDE VIEW Notes: (1) All dimensions are in millimeters. Angles in degrees. (2) Complies with JEDEC MO-193.
END VIEW
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CAT4002A, CAT4004A
Example of Ordering Information (Note 4)
Prefix CAT Device # 4004A Suffix HU2 -G T3
Company ID (Optional) Product Number 4002A 4004A
Package HU2: UDFN TD: TSOT SD: SC70
Lead Finish G: NiPdAu
Tape & Reel (Note 6) T: Tape & Reel 3: 3,000 Units / Reel
Table 8. ORDERING INFORMATION
Part Number CAT4002ASD-GT3 CAT4002ATD-GT3 CAT4004AHU2-GT3 2. 3. 4. 5. 6. Package SC70-6 TSOT-23 UDFN-8 (2 x 2 mm) Quantity per Reel 3,000 3,000 3,000
All packages are RoHS-compliant (Lead-free, Halogen-free). The standard lead finish is NiPdAu. The device used in the above example is a CAT4004AHU2-GT3 (UDFN, NiPdAu, Tape & Reel, 3,000/Reel). 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 nor the rights of others. SCILLC products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death may occur. Should Buyer purchase or use SCILLC products for any such unintended or unauthorized application, Buyer shall indemnify and hold SCILLC and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal Opportunity/Affirmative Action Employer. This literature is subject to all applicable copyright laws and is not for resale in any manner.
PUBLICATION ORDERING INFORMATION
LITERATURE FULFILLMENT: Literature Distribution Center for ON Semiconductor P.O. Box 5163, Denver, Colorado 80217 USA Phone: 303-675-2175 or 800-344-3860 Toll Free USA/Canada Fax: 303-675-2176 or 800-344-3867 Toll Free USA/Canada Email: orderlit@onsemi.com N. American Technical Support: 800-282-9855 Toll Free USA/Canada Europe, Middle East and Africa Technical Support: Phone: 421 33 790 2910 Japan Customer Focus Center Phone: 81-3-5773-3850 ON Semiconductor Website: www.onsemi.com Order Literature: http://www.onsemi.com/orderlit For additional information, please contact your local Sales Representative
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CAT4002A/D

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