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 http://onsemi.com 1 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. http://onsemi.com 2 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 http://onsemi.com 3 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) http://onsemi.com 4 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) http://onsemi.com 5 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 http://onsemi.com 6 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. http://onsemi.com 7 CAT3603 Block Diagram Figure 21. CAT3603 Functional Block Diagram http://onsemi.com 8 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. http://onsemi.com 9 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 http://onsemi.com 10 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. 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