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CAT4101 1 A Constant-Current LED Driver with PWM Dimming
Description
The CAT4101 is a constant-current sink driving a string of high-brightness LEDs up to 1 A with very low dropout of 0.5 V at full load. It requires no inductor, provides a low noise operation and minimizes the number of components. The LED current is set by an external resistor connected to the RSET pin. The LED pin is compatible with high voltage up to 25 V, allowing the driving of long strings of LEDs. The device ensures an accurate and regulated current in the LEDs independent of supply and LED forward voltage variation. The PWM/EN input allows the device shutdown and the LED brightness adjustment by using an external pulse width modulation (PWM) signal. The driver features a thermal shutdown protection that becomes active whenever the die temperature exceeds 150C. The device is available in a high-power, 5-lead TO-263 package offering excellent thermal dissipation characteristics.
Features
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TO-263 TV SUFFIX CASE 221AE
PIN CONNECTIONS
EN/PWM VIN GND RSET LED (Top View) 1
TAB
* * * * * * * * *
Accurate 1 A Current Sink Up to 25 V Operation on LED Pin Low Dropout 500 mV at 1 A LED Current Set by External Resistor High Resolution PWM Dimming via EN/PWM "Zero" Current Shutdown Mode Thermal Shutdown Protection TO-263 5-lead Package These Devices are Pb-Free, Halogen Free/BFR Free and are RoHS Compliant
MARKING DIAGRAM
CAT4101TV 3LYMXXXXA
Applications
* High Power LED up to 1 A * Architectural and General Lighting * Automotive Lighting
VCC 3 V to 25 V VIN 5V OFF ON LEDs 1A VIN CAT4101 EN/PWM LED RSET GND
CAT4101TV = Specific Device Code 3 = Lead Finish (Matte-Tin) L = Assembly Location Code Y = Production Year (Last Digit) M = Production Month (1-9, A, B, C) XXXX = Last Four Digits of Assembly Lot Number A = Production Revision (Fixed as "A")
ORDERING INFORMATION
Device CAT4101TV-T75 (Note 1) Package TO-263 (Pb-Free) Shipping 750/ Tape & Reel
549 W
Figure 1. Typical Application Circuit
1
1. Lead Finish Matte-Tin
(c) Semiconductor Components Industries, LLC, 2010
February, 2010 - Rev. 4
Publication Order Number: CAT4101/D
CAT4101
Table 1. ABSOLUTE MAXIMUM RATINGS
Parameter VIN, RSET, EN/PWM LED Voltage Storage Temperature Range Junction Temperature Range Lead Temperature Rating 6 25 -65 to +160 -40 to +150 300 Units 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. RECOMMENDED OPERATING CONDITIONS
Parameter VIN Ambient Temperature Range LED Pin Current NOTE: Typical application circuit with external components is shown on page 1. Rating 3.0 to 5.5 -40 to +85 Up to 1 Units V _C A
Table 3. ELECTRICAL OPERATING CHARACTERISTICS (Min and Max values in bold are over recommended operating
conditions unless specified otherwise. Typical values are at VIN = 5.0 V, TAMB = 25C) Symbol ILED-ACC Parameter LED Current Accuracy Conditions VLED = 1 V, RSET = 1.47 kW VLED = 1 V, RSET = 750 W VLED = 1 V, RSET = 549 W VDOUT VRSET IQ IQSHDN REN/PWM VHI VLO TSD THYS ILED/IRSET VUVLO Dropout Voltage RSET Pin Voltage Quiescent Current No LED, RSET = Floating No LED, RSET = 549 W Shutdown Current EN/PWM Pin - Pull-down resistance - Logic High Level - Logic Low Level Thermal Shutdown Thermal Hysteresis RSET to LED Current gain ratio Undervoltage lockout (UVLO) Threshold 100 mA LED current VEN = 0 V 200 1.3 0.4 150 20 400 2.0 V ILED = 1 A 1.17 Min 315 Typ 350 700 1000 500 1.20 0.8 8.0 1 mA kW V V _C _C 1.23 mV V mA Max 385 Units mA
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CAT4101
Table 4. RECOMMENDED EN/PWM TIMING
(For 3.0 V VIN 5.5 V, over full ambient temperature range -40C to +85C.) Symbol TPS TP1 TP2 TR TF TLO THI TPWRDWN Name Turn-On time, EN/PWM rising to ILED from Shutdown Turn-On time, EN/PWM rising to ILED Turn-Off time, EN/PWM falling to ILED LED rise time LED fall time EN/PWM low time EN/PWM high time EN/PWM low time to shutdown delay THI TLO EN/PWM SHUTDOWN TP2 TPS LED CURRENT 50% SHUTDOWN 0 mA 50% 10% 0 mA TP1 TR 90% TF ILED = (1.2 V / RSET) x 400 SHUTDOWN Conditions ILED = 1 A ILED = 350 mA ILED = 1 A ILED = 350 mA ILED = 1 A ILED = 350 mA ILED = 1 A ILED = 350 mA ILED = 1 A ILED = 350 mA 1 5 8 TPWRDWN Min Typ 1.6 1.1 920 620 440 310 840 390 470 350 Max Units ms ns ns ns ns ms ms ms
VIN QUIESCENT CURRENT SHUTDOWN 0 mA SHUTDOWN
Figure 2. CAT4101 EN/PWM Timing
EN/PWM Operation The EN/PWM pin has two primary functions. One function enables and disables the device. The other function turns the LED channel on and off for PWM dimming control. The device has a very fast turn-on time (from EN/PWM rising to LED on) and allows "instant on" when dimming LED using a PWM signal. Accurate linear dimming is compatible with PWM frequencies from 100 Hz to 5 kHz for PWM duty cycle down to 1%. PWM frequencies up to 50 kHz can be supported for duty cycles greater than 10%.
When performing a combination of low frequencies and small duty cycles, the device may enter shutdown mode. This has no effect on the dimming accuracy, because the turn-on time TPS is very short, in the range of 1 ms. To ensure that PWM pulses are recognized, pulse width low time TLO should be longer than 1 ms. The CAT4101 enters a "zero current" shutdown mode after a 5 ms delay (typical) when EN/PWM is held low.
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CAT4101
TYPICAL PERFORMANCE CHARACTERISTICS
(VIN = 5 V, VCC = 5 V, VF = 3.5 V, ILED = 1 A (1 LED), CIN = 1 mF, TAMB = 25C unless otherwise specified.) 1.2 QUIESCENT CURRENT (mA) QUIESCENT CURRENT (mA) 4.5 5.0 5.5 No Load 1.0 8.0
6.0
0.8
4.0
0.6
2.0
0.4
3.0
3.5
4.0
0
0
200
400
600
800
1000
INPUT VOLTAGE (V)
LED CURRENT (mA)
Figure 3. Quiescent Current vs. VIN Voltage (ILED = 0 mA)
8.5 QUIESCENT CURRENT (mA) Full Load LED CURRENT (A) 8.0 1.2 1.0 0.8 0.6 0.4 0.2 6.5 0
Figure 4. Quiescent Current vs. LED Current
7.5
7.0
3.0
3.5
4.0
4.5
5.0
5.5
0
0.3
0.6
0.9
1.2
1.5
INPUT VOLTAGE (V)
LED PIN VOLTAGE (V)
Figure 5. Quiescent Current vs. VIN Voltage (Full Load)
1.2 1.1 1.0 LED CURRENT (A) LED CURRENT (A) 0.9 0.8 0.7 0.6 0.5 0.4 0.3 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 1.2 1.1 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 -40
Figure 6. LED Current vs. LED Pin Voltage
0
40 TEMPERATURE (C)
80
120
INPUT VOLTAGE (V)
Figure 7. LED Current Change vs. VIN Voltage
Figure 8. LED Current Change vs. Temperature
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CAT4101
TYPICAL PERFORMANCE CHARACTERISTICS
(VIN = 5 V, VCC = 5 V, VF = 3.5 V, ILED = 1 A (1 LED), CIN = 1 mF, TAMB = 25C unless otherwise specified.) 1.30 1.30
RSET VOLTAGE (V)
1.20
RSET VOLTAGE (V) 3.0 3.5 4.0 4.5 5.0 5.5
1.25
1.25
1.20
1.15
1.15
1.10
1.10 -40
0
40 TEMPERATURE (C)
80
120
INPUT VOLTAGE (V)
Figure 9. RSET Pin Voltage vs. VIN Voltage
1.2 1.0 LED CURRENT (A) 0.8 0.6 0.4 0.2 0
Figure 10. RSET Pin Voltage vs. Temperature
0
1
2
3
4
5
RSET (kW)
Figure 11. LED Current vs. RSET Resistor
100 ENABLE THRESHOLD (V) 1.4 1.2 1.0 0.8 0.6 0.4
Figure 12. PWM 200 Hz, 1% Duty Cycle
LED CURRENT (%)
10
-40C 25C 85C
1 100 Hz 0.1 1 kHz 0.1 5 kHz 1 50 kHz 10 100
3.0
3.5
4.0
4.5
5.0
5.5
DUTY CYCLE (%)
INPUT VOLTAGE (V)
Figure 13. LED Current vs. PWM Duty Cycle
Figure 14. EN/PWM Threshold vs. VIN
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CAT4101
Table 5. PIN DESCRIPTIONS
Name EN/PWM VIN GND RSET LED TAB Pin 1 2 3 4 5 - Function Device enable (active high) and PWM control. Device supply input, connect to battery or supply. Ground reference. A resistor connected between this pin and ground sets the LED current. Bottom LED cathode terminal. Connect TAB to the Ground plane.
Pin Function VIN is the supply pin for the device. A small 0.1 mF ceramic bypass capacitor is optional for noisy environments. The maximum operating voltage is 6.0 V. Whenever the input supply falls below the under-voltage threshold, the current sink will automatically be disabled. EN/PWM is the enable and one wire dimming input for the LED channel. Guaranteed levels of logic high and logic low are set at 1.3 V and 0.4 V respectively. When EN/PWM is initially taken high, the device becomes enabled and the LED current is set at a gain of 400 times the current in RSET. To place the device into zero current shutdown mode, the EN/PWM pin must be held low for 5 ms typical. LED pin is connected to the bottom LED cathode and provides a regulated current sink. The pin enters a
high-impedance zero-current state whenever the device is placed in shutdown mode. RSET pin is connected to an external resistor to set the LED current. The ground side of the external resistor should be star connected to the GND of the PCB. The pin source current mirrors the current to the LED sink. The voltage at this pin is regulated to 1.2 V. GND is the ground reference for the device. The pin must be connected to the ground plane on the PCB. 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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CAT4101
Block Diagram
VIN LED VIN Undervoltage & Thermal Lockout Shutdown Delay
EN/PWM
Reference Voltage
Current Regulator
RSET
RSET Regulator & Mirror GND
Figure 15. CAT4101 Functional Block Diagram
Basic Operation The CAT4101 has one highly accurate LED current sink to regulate LED current in a string of LEDs. The LED current is mirrored from the current flowing from the RSET pin. Table 6 lists various RSET resistor values for LED current in 100 mA increments. The LED channel needs a minimum of 500 mV headroom to sink constant regulated current. If the input supply falls below 2 V, the under-voltage lockout circuit disables the LED channel. For applications requiring current higher than 1 A, several CAT4101 devices can be connected in parallel. The LED channel can withstand and operate at voltages up to 25 V. This makes the device ideal for driving long strings of high power LEDs from a high voltage source.
Table 6. RSET RESISTOR SETTINGS
LED Current [mA] 100 200 300 400 500 600 700 800 900 1000 RSET [W] 4990 2490 1690 1270 1050 866 768 680 604 549
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CAT4101
Application Information
Single 12 V Supply
The circuit shown in Figure 16 shows how to power three LEDs in series from a single 12 V supply using the CAT4101. The CAT4101 can not be driven directly from 12 V, three components are needed to create a lower voltage for the VIN pin (below 5.5 V). Resistor R2 and zener diode D provide a regulated voltage while the quiescent current runs through the N-Channel transistor M. Suitable parts for this circuit are the ON Semiconductor MM3Z6V2 zener diode and the 2N7002L N-channel transistor (SOT23 package).
12 V C2 1 mF R2 5 kW D 6.2 V VIN C1 0.1 mF LED
For a given package style and board layout, the operating junction temperature TJ is a function of the power dissipation PD, and the ambient temperature, resulting in the following equation:
T J + TAMB ) P D(q JC ) q CA) + T AMB ) P D q JA
The CAT4101 TO-263 5-lead package provides a thermal resistance when the ground tab is soldered down to the PCB. When mounted on a double-sided printed circuit board with two square inches of copper allocated for "heat spreading", the resulting qJA is about 30C/W. For example, at 60C ambient temperature, the maximum power dissipation is calculated as follow:
P Dmax + T Jmax * T AMB + 150 * 60 + 3 W 30 q JA
M
Recommended Layout
CAT4101 EN/PWM RSET GND
R1
The board layout should provide good thermal dissipation through the PCB. Multiple via can be used to connect the tab of the CAT4101 to a large ground plane underneath the package. Input capacitor C1 should be placed as close to the driver IC as possible. The RSET resistor should have a Kelvin connection to the GND pin of the CAT4101.
Figure 16. Single Supply Driving Three LEDs Power Dissipation
The power dissipation (PD) of the CAT4101 can be calculated as follows:
P D + (V IN I IN) ) (V LED ILED)
where VLED is the voltage at the LED pin. Combinations of high VLED voltage or high ambient temperature can cause the CAT4101 to enter thermal shutdown. In applications where VLED is high, a resistor can be inserted in series with the LED string to lower PD. Thermal dissipation of the junction heat consists primarily of two paths in series. The first path is the junction to the case (qJC) thermal resistance which is defined by the package style, and the second path is the case to ambient (qCA) thermal resistance, which is dependent on board layout. The overall junction to ambient (qJA) thermal resistance is equal to:
q JA + q JC ) q CA Figure 17. CAT4101 Recommended Layout
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CAT4101
PACKAGE DIMENSIONS
TO-263, 5 Lead CASE 221AE-01 ISSUE O
E A c2 L1
D1
D H A1
PIN#1 ID
c L e TOP VIEW b END VIEW BOTTOM VIEW
SYMBOL A A1 b c c2 D D1 E e H L L1 q
MIN 4.20 0.00 0.60 0.33 1.15 8.40 6.86 9.80
NOM
MAX 4.80 0.25 0.88 0.50 1.60 9.60 10.67
1.70 BSC 14.61 1.78 15.87 2.79 1.67
Notes: (1) All dimensions are in millimeters. Angles in degrees. (2) Complies with JEDEC standard TO-263.
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CAT4101
Example of Ordering Information (Note 4)
Prefix CAT Device # 4101 Suffix TV- T75
Company ID (Optional)
Product Number 4101
Package TV: TO-263
Tape & Reel (Note 6) T: Tape & Reel 75: 750 / Reel
2. 3. 4. 5. 6.
All packages are RoHS-compliant (Lead-free, Halogen-free). The standard plated finish is Matte-Tin. The device used in the above example is a CAT4101TV-T75 (TO-263, Tape & Reel, 750/Reel). For additional 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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CAT4101/D

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