CAT4101 1 A Constant-Current LED Driver with PWM Dimming FEATURES 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. 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 APPLICATIONS The PWM/EN input allows the device shutdown and the LED brightness adjustment by using an external pulse width modulation (PWM) signal. High Power LED up to 1 A Architectural and General Lighting Automotive Lighting The driver features a thermal shutdown protection that becomes active whenever the die temperature exceeds 150ºC. ORDERING INFORMATION Part Number Package Quantity per Reel Package Marking 750 CAT4101TV CAT4101TV-T75 TO-263-5* The device is available in a high-power, 5-lead TO-263 package offering excellent thermal dissipation characteristics. * Lead Finish Matte-Tin PIN CONFIGURATION TYPICAL APPLICATION CIRCUIT VCC 3V to 25V Top View VIN 5V EN/PWM 1 VIN 2 GND 3 Tab OFF ON RSET 4 LED 5 © 2009 SCILLC. All rights reserved. Characteristics subject to change without notice 549Ω 1 LEDs 1A VIN CAT4101 EN/PWM LED RSET GND Doc. No. MD-5036, Rev. D CAT4101 ABSOLUTE MAXIMUM RATINGS Parameter Rating Units VIN, RSET, EN/PWM 6 V LED Voltage 25 V Storage Temperature Range -65 to +160 °C Junction Temperature Range -40 to +150 °C 300 °C Rating Units VIN 3.0 to 5.5 V Ambient Temperature Range -40 to +85 °C Up to 1 A Lead Temperature RECOMMENDED OPERATING CONDITIONS Parameter LED Pin Current Typical application circuit with external components is shown on page 1. 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 = 25°C Symbol ILED-ACC Name LED Current Accuracy VDOUT Dropout Voltage VRSET RSET Pin Voltage IQ Quiescent Current IQSHDN TSD Shutdown Current EN/PWM Pin • Pull-down resistance • Logic High Level • Logic Low Level Thermal Shutdown THYS Thermal Hysteresis REN/PWM VHI VLO ILED/IRSET VUVLO RSET to LED Current gain ratio Conditions Min Typ Max VLED = 1 V, RSET = 1.47 kΩ 315 350 385 VLED = 1 V, RSET = 750 Ω 700 VLED = 1 V, RSET = 549 Ω 1000 ILED = 1 A 500 1.17 No LED, RSET = Floating 0.8 No LED, RSET = 549 Ω 8.0 VEN = 0 V mA mV 1.23 1 µA 0.4 kΩ V V 200 100 mA LED current 150 °C 20 °C 400 2.0 2 V mA 1.3 Undervoltage lockout (UVLO) Threshold Doc. No. MD-5036, Rev. D 1.20 Units V © 2009 SCILLC. All rights reserved. Characteristics subject to change without notice CAT4101 RECOMMENDED EN/PWM TIMING For 3.0 V ≤ VIN ≤ 5.5 V, over full ambient temperature range -40ºC to +85ºC. Symbol Name Conditions TPS Turn-On time, EN/PWM rising to ILED from Shutdown ILED = 1 A ILED = 350 mA 1.6 1.1 μs TP1 Turn-On time, EN/PWM rising to ILED ILED = 1 A ILED = 350 mA 920 620 ns TP2 Turn-Off time, EN/PWM falling to ILED ILED = 1 A ILED = 350 mA 440 310 ns TR LED rise time ILED = 1 A ILED = 350 mA 840 390 ns TF LED fall time ILED = 1 A ILED = 350 mA 470 350 ns TLO EN/PWM low time 1 μs THI EN/PWM high time 5 μs TPWRDWN Min Typ EN/PWM low time to shutdown delay Max 8 Units ms TPWRDWN THI TLO EN/PWM SHUTDOWN SHUTDOWN 0mA TP2 TF TPS TP1 TR ILED = (1.2V/RSET) x 400 90% LED CURRENT 50% 50% 10% SHUTDOWN 0mA 0mA VIN QUIESCENT CURRENT SHUTDOWN 0mA SHUTDOWN 0mA Figure 1. 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. 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 µs. To ensure that PWM pulses are recognized, pulse width low time TLO should be longer than 1μs. The CAT4101 enters a “zero current” shutdown mode after a 5 ms delay (typical) when EN/PWM is held low. 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%. © 2009 SCILLC. All rights reserved. Characteristics subject to change without notice 3 Doc. No. MD-5036, Rev. D CAT4101 TYPICAL PERFORMANCE CHARACTERISTICS VIN = 5 V, VCC = 5 V, VF = 3.5 V, ILED = 1 A (1 LED), CIN = 1 μF, TAMB = 25°C unless otherwise specified. Quiescent Current vs. VIN Voltage (ILED = 0 mA) Quiescent Current vs. LED Current 8.0 QUIESCENT CURRENT [mA] QUIESCENT CURRENT [mA] 1.2 No Load 1.0 0.8 0.6 3.0 3.5 4.0 4.5 5.0 INPUT VOLTAGE [V] 2.0 0 5.5 Quiescent Current vs. VIN Voltage (Full Load) 200 400 600 800 LED CURRENT [mA] 1000 LED Current vs. LED Pin Voltage 1.2 8.5 Full Load 1.0 8.0 LED CURRENT [A] QUIESCENT CURRENT [mA] 4.0 0.0 0.4 7.5 7.0 0.8 0.6 0.4 0.2 0.0 6.5 3.0 3.5 4.0 4.5 5.0 INPUT VOLTAGE [V] 0.0 5.5 0.3 0.6 0.9 1.2 LED PIN VOLTAGE [V] 1.5 LED Current Change vs. Temperature LED Current Change vs. VIN Voltage 1.2 1.2 1.1 1.1 1.0 1.0 LED CURRENT [A] LED CURRENT [A] 6.0 0.9 0.8 0.7 0.6 0.5 0.4 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.3 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 INPUT VOLTAGE [V] Doc. No. MD-5036, Rev. D -40 4 0 40 80 TEMPERATURE [ºC] 120 © 2009 SCILLC. All rights reserved. Characteristics subject to change without notice CAT4101 TYPICAL PERFORMANCE CHARACTERISTICS VIN = 5 V, VCC = 5 V, VF = 3.5 V, ILED = 1 A (1 LED), CIN = 1 μF, TAMB = 25°C unless otherwise specified. RSET Pin Voltage vs. VIN Voltage RSET Pin Voltage vs. Temperature 1.30 RSET VOLTAGE [V] RSET VOLTAGE [V] 1.30 1.25 1.20 1.15 1.25 1.20 1.15 1.10 1.10 3.0 3.5 4.0 4.5 5.0 INPUT VOLTAGE [V] -40 5.5 0 40 80 TEMPERATURE [ºC] 120 PWM 200 Hz, 1% Duty Cycle LED Current vs. RSET Resistor 1.2 LED CURRENT [A] 1.0 0.8 0.6 0.4 0.2 0.0 0 1 2 3 RSET [kΩ] 4 5 LED Current vs. PWM Duty Cycle EN/PWM Threshold vs. VIN 1.4 ENABLE THRESHOLD [V] LED CURRENT [%] 100 10 100Hz 50kHz 1 5kHz 1kHz 0.1 0.1 1 10 -40ºC 25ºC 1.0 0.8 85ºC 0.6 0.4 100 3.0 DUTY CYCLE [%] © 2009 SCILLC. All rights reserved. Characteristics subject to change without notice 1.2 5 3.5 4.0 4.5 5.0 INPUT VOLTAGE [V] 5.5 Doc. No. MD-5036, Rev. D CAT4101 PIN DESCRIPTIONS Name Pin Function EN/PWM 1 Device enable (active high) and PWM control. VIN 2 Device supply input, connect to battery or supply. GND 3 Ground reference. RSET 4 A resistor connected between this pin and ground sets the LED current. LED 5 Bottom LED cathode terminal. TAB – Connect TAB to the Ground plane. PIN FUNCTION VIN is the supply pin for the device. A small 0.1 µF 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. 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. 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 respetively. 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. 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. LED pin is conneted to the bottom LED cathode and provides a regulated current sink. The pin enters a Doc. No. MD-5036, Rev. D 6 © 2009 SCILLC. All rights reserved. Characteristics subject to change without notice CAT4101 BLOCK DIAGRAM VIN LED VIN EN/PWM Undervoltage & Thermal Lockout Shutdown Delay Reference Voltage Current Regulator RSET RSET Regulator & Mirror GND Figure 2. 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 according to the following formula: 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. 1.2 V ILED ≅ 400 × RSET 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. © 2009 SCILLC. All rights reserved. Characteristics subject to change without notice Table 1. RSET Resistor Settings 7 LED Current [mA] RSET [Ω] 100 4870 350 1470 700 750 1000 549 Doc. No. MD-5036, Rev. D CAT4101 APPLICATION INFORMATION 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: SINGLE 12 V SUPPLY The circuit shown in Figure 3 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). TJ = TAMB + PD (θJC + θCA) = TAMB + PD θJA 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 θJA is about 30°C/W. For example, at 60°C ambient temperature, the maximum power dissipation is calculated as follow: 12 V C2 1 µF R2 5 kΩ PDmax = M D 6.2 V VIN LED RECOMMENDED LAYOUT C1 0.1 µF 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. CAT4101 EN/PWM R1 TJmax - TAMB 150 - 60 = = 3W θ JA 30 RSET GND 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 3. Single Supply Driving Three LEDs POWER DISSIPATION The power dissipation (PD) of the CAT4101 can be calculated as follows: PD = (VIN × IIN ) + (VLED × 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 (θJC) thermal resistance which is defined by the package style, and the second path is the case to ambient (θCA) thermal resistance, which is dependent on board layout. The overall junction to ambient (θJA) thermal resistance is equal to: θJA = θJC + θCA Doc. No. MD-5036, Rev. D Figure 4. CAT4101 Recommended Layout 8 © 2009 SCILLC. All rights reserved. Characteristics subject to change without notice CAT4101 PACKAGE OUTLINE DRAWING TO-263 5-Lead (TV) (1)(2) 0F0F E A c2 L1 D1 D H A1 PIN#1 ID c L e θ b TOP VIEW END VIEW BOTTOM VIEW SYMBOL MIN A A1 b c c2 D D1 E e H L L1 θ 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 0º 15.87 2.79 1.67 8º For current Tape and Reel information, download the PDF file from: http://www.catsemi.com/documents/tapeandreel.pdf. Notes: (1) All dimensions are in millimeters. Angles in degrees. (2) Complies with JEDEC standard TO-263. © 2009 SCILLC. All rights reserved. Characteristics subject to change without notice 9 Doc. No. MD-5036, Rev. D CAT4101 EXAMPLE OF ORDERING INFORMATION (1) 1F1F Prefix CAT Device # Suffix 4101 TV– Package TV: TO-263 Company ID Product Number T75 Tape & Reel T: Tape & Reel 75: 750/Reel 4101 Notes: (1) All packages are RoHS-compliant (Lead-free, Halogen-free). (2) The standard plated finish is Matte-Tin. (3) The device used in the above example is a CAT4101TV-T75 (TO-263, Matte-Tin, Tape & Reel, 750/Reel). (4) For additional temperature options, please contact your nearest ON Semiconductor Sales office. Doc. No. MD-5036, Rev. D 10 © 2009 SCILLC. All rights reserved. Characteristics subject to change without notice CAT4101 REVISION HISTORY Date 21-Aug-08 17-Nov-08 03-Feb-09 Revision A B C 13-Mar-09 D Description Initial Issue Change logo and fine print to ON Semiconductor Update Application Information – Single 12 V Supply Updated Electrical Operating Characteristics Added new Typical Performance Characteristics Updated Block Diagram Updated Application Information – Single 12 V Supply 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: [email protected] © 2009 SCILLC. All rights reserved. Characteristics subject to change without notice 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 11 ON Semiconductor Website: www.onsemi.com Order Literature: http://www.onsemi.com/orderlit For additional information, please contact your local Sales Representative Doc. No. MD-5036 Rev. D