CAT3604 4-Channel Regulated Charge Pump White LED Driver FEATURES ■ ■ Drives individually up to 4 LEDs ■ Output current up to 30mA per LED Automatic short circuit detect/disable ■ High-frequency Operation at 1MHz ■ Digital control On/Off of each LED ■ ■ Compatible with supply voltage of 3V to 5.5V Low value ceramic capacitors ■ "604" compatible pinout ■ Soft start and current limiting ■ Thin QFN 16-lead package, 4x4mm, 0.8mm max height ■ Power efficiency up to 93% ■ 2 modes of operation 1x and 1.5x APPLICATIONS ■ ■ Color LCD and keypad Backlighting ■ Cellular Phones ■ Handheld Devices Digital Cameras ■ PDAs ■ Portable MP3 players DESCRIPTION 5.5V, making the device ideal for battery-powered applications. The CAT3604 is a charge pump operating in either 1x (LDO) mode or 1.5x fractional mode regulating current through each of the 4 LED pins. Operation at a fixed high frequency of 1MHz typical allows the use of very small value ceramic capacitors. LED dimming can be accomplished by several methods including using a DC voltage to set the RSET pin current, applying a PWM signal on the Control signals, or adding a switched resistor in parallel with RSET. The Enable input pin allows the device to be placed in power-down mode with "zero” quiescent current. The CAT3604 drives white light-emitting diodes (LEDs) connected in parallel and provides tightly matched regulated current to achieve uniformity of brightness in LCD backlighting applications. An external resistor RSET controls the output current level. LED currents of up to 30mA are supported over a range of input supply voltages from 3V to The CAT3604 features short circuit and overcurrent limiting protection. The device is available in a 16lead thin QFN package with a max height of 0.8mm. TYPICAL APPLICATION C1+ C1- C2+ C2VOUT VIN COUT Battery + VIN 3V to 4.2V EN CIN EN CAT3604 Control 0 CTR0 LED1 Control 1 CTR1 LED2 Control 2 CTR2 LED3 20mA LED4 RSET GND RSET © 2005 by Catalyst Semiconductor, Inc. Characteristics subject to change without notice 1 Doc. No. 5008, Rev. I CAT3604 ORDERING INFORMATION Part Number Package Quantity per Reel Package Marking CAT3604HS4-TE13 Thin QFN-16 4x4mm 2000 C364 CAT3604HV4-TE13 Thin QFN-16 4x4mm Lead Free 2000 G364 PIN CONFIGURATION Top View LED1 LED2 LED3 LED4 16 15 14 13 EN 1 12 GND CTR0 2 11 C2+ CTR1 3 10 C2- CTR2 4 9 C1- GND 5 6 RSET VOUT 7 8 VIN C1+ 16-lead Thin QFN (4mm x 4mm) Note: The package exposed pad is electrically connected inside the package to GND and to pin 12. PIN DESCRIPTIONS Pin Number Name Function 1 EN Enable input, active HIGH 2 CTR0 Digital control input 0 3 CTR1 Digital control input 1 4 CTR2 Digital control input 2 5 RSET The LED output current is set by the current sourced out of the RSET pin 6 VOUT 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 13 LED4 LED 4 cathode terminal 14 LED3 LED 3 cathode terminal 15 LED2 LED 2 cathode terminal 16 LED1 LED 1 cathode terminal Pad GND Pad Ground reference Doc. No. 5008, Rev. I 2 © 2005 by Catalyst Semiconductor, Inc. Characteristics subject to change without notice CAT3604 ABSOLUTE MAXIMUM RATINGS Parameter Rating Unit VIN, VOUT, LEDx voltage -0.3 to 7.0 V EN, CTRx voltage -0.3 to VIN V RSET voltage -0.3 to VIN V RSET current +1 mA Ambient Temperature Range -40 to +85 o C Storage Temperature Range -65 to +160 o C Lead Temperature 300 o C ESD Ratings Human Body Model (HBM) Machine Model (MM) (note 1) 2000 200 Note 1: V V Machine model is with 200pF capacitor discharged directly into each pin. RECOMMENDED OPERATING CONDITIONS Parameter Rating Unit VIN 3.0 to 5.5 V Ambient Temperature Range -40 to +85 Input/Output/Bucket Capacitors o C 1 +20% typical µF 0 to 30 mA ILED per LED pin ELECTRICAL OPERATING CHARACTERISTICS Limits over recommended operating conditions unless specified otherwise. Typical values at TA = 25˚C, VIN = 3.5V, IRSET = 5µA Symbol Parameter Conditions IQ Quiescent Current VEN = 0V Shutdown Mode 1x Mode, No Load 1.5x Mode, No Load VRSET RSET Regulated Voltage ILED Programmed LED Current IRSET = 5µA IRSET = 37µA IRSET = 78µA 2.4 15.0 30.0 mA mA mA ILED-ACC LED Current Accuracy 0.5mA < ILED < 3mA 3mA < ILED < 30mA +15 +5 % % ILED-DEV LED Channel Matching (ILED - ILEDAVG) / ILEDAVG +3 ROUT Output Resistance (Open Loop) 1x Mode 1.5x Mode, IOUT = 100mA 1.4 6.5 2.5 10 % Ω Ω 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 IEN-CTR Input Leakage Current On Inputs EN, CTR0, 1 & 2 0.001 1 µA VEN-CTR High Detect Threshold Low Detect Threshold On Inputs EN, CTR0, 1 & 2 0.8 0.7 1.3 0.4 V V ISC Input Current Limit VOUT = GND 30 45 60 mA ILIM Maximum Input Current VOUT > 1V 200 400 600 mA © 2005 by Catalyst Semiconductor, Inc. Characteristics subject to change without notice Min 1.17 3 Typ Max Unit 0.05 0.3 2.6 1 1 5 µA mA mA 1.2 1.23 V Doc. No. 5008, Rev. I CAT3604 BLOCK DIAGRAM C1- 3<VIN<4.2V Battery C2+ 1x mode (LDO) 1.5x Charge Pump VIN + C1+ C2- VOUT CIN COUT - Mode Control 1MHz Oscillator EN LED1 LED2 LED3 1.2V Ref 20mA LED4 RSET CTR0 CTR1 CTR2 Current Setting 4 Current Sink Regulators LED Output Select Figure 1: CAT3604 Functional Block Diagram BASIC OPERATION At power-up, the CAT3604 starts operation in 1x mode. If it is able to drive the programmed LED current, it continues in 1x mode. If the battery voltage drops to a level where the LED current cannot be met, the driver automatically switches into 1.5x mode. The 1.5x charge pump will boost the output voltage accordingly to achieve the nominal LED current. Doc. No. 5008, Rev. I The operating mode is reinitialized each and every time the chip is powered up or is taken out of shutdown mode (via EN pin). The use of the control pins (CTR0, CTR1, CTR2) does not reconfigure the mode of operation. 4 © 2005 by Catalyst Semiconductor, Inc. Characteristics subject to change without notice CAT3604 LED CURRENT SETTING SHORT CIRCUIT DETECT/DISABLE The LED current is set by the external resistor RSET connected between the RSET pin and ground. Table 1 lists various LED currents and the associated RSET resistor value for standard 1% precision surface mount resistors. The unused LED channels can also be turned off by connecting the respective LED pins to VOUT. In which case, the corresponding LED driver is disabled and the typical LED sink current is only about 20µA. When the following equation is true on any channel, the driver turns off the LED channel: LED Current (mA) RSET (kΩ) VOUT - VLED ≤ 1V (LED channel OFF) Note: The CAT3604 is designed to drive LEDs with forward voltage greater than 1V and is not compatible with resistive loads. 1 649 2 287 5 102 10 49.9 15 32.4 20 23.7 30 15.4 Table 1. RSET Resistor Selection The digital control lines CTR0, CTR1 adn CTR2 allow to turn On or Off a combition of LEDs as shown in Table 2. Control Lines LED Outputs CTR2 CTR1 CTR0 LED4 LED3 LED2 LED1 0 0 0 - - - ON 0 0 1 - - ON - 0 1 0 - ON - - 0 1 1 ON - - - 1 0 0 - - ON ON 1 0 1 - ON ON ON 1 1 0 ON ON ON ON 1 1 1 - - - - Table 2: LED Selection Notes: 1 = logic high (or VIN) 0 = logic low (or GND) - = LED output OFF © 2005 by Catalyst Semiconductor, Inc. Characteristics subject to change without notice 5 Doc. No. 5008, Rev. I CAT3604 TYPICAL CHARACTERISTICS VIN = 3.6V, EN = VIN, CIN = COUT = 1µF, RSET = 24kΩ, TAMB = 25˚C, unless otherwise specified. Efficiency vs. Total LED Current (4 LEDs) Efficiency vs. Input Voltage (4 LEDs) 100 100 1x mode VIN = 4V (1x mode) 90 80 EFFICIENCY (%) EFFICIENCY (%) 90 1.5x mode 70 60 20mA per LED 15mA per LED 50 40 80 70 60 VIN = 3.2V (1.5x mode) 50 40 4.2 4.0 3.8 3.6 3.4 3.2 3.0 0 DISCHARGING BATTERY [V] 150 200 LED Current vs. Temperature 24 16.0 LED CURRENT [mA] 1 LED at 20mA 22 LED CURRENT [mA] 100 TOTAL LED CURRENT [mA] LED Current vs. Input Voltage 20 4 LEDs at 20mA 18 16 14 4 LEDs at 15mA 12 10 4 LEDs at 15mA Vin = 4V 15.5 15.0 14.5 14.0 3.0 3.2 3.4 3.6 3.8 4.0 INPUT VOLTAGE [V] 4.2 -50 -25 0 25 50 75 100 125 TEMPERATURE [˚C] Ground Current vs. Input Voltage (1x mode) Ground Current vs. Temperature (1x mode) 0.5 0.5 GROUND CURRENT [mA] GROUND CURRENT [mA] 50 0.4 0.3 0.2 4 LEDs OFF 0.1 0.0 0.4 0.3 0.2 0.1 4 LEDs OFF Rset = 500k 0.0 3.0 Doc. No. 5008, Rev. I 3.2 3.4 3.6 3.8 4.0 INPUT VOLTAGE [V] 4.2 -40 -20 0 20 40 60 80 100 TEMPERATURE [˚C] 6 © 2005 by Catalyst Semiconductor, Inc. Characteristics subject to change without notice CAT3604 TYPICAL CHARACTERISTICS VIN = 3.6V, EN = VIN, CIN = COUT = 1µF, RSET = 24kΩ, TAMB = 25˚C, unless otherwise specified. Supply Current vs. Input Voltage Ground Current vs. Input Voltage (1.5x mode) 100 SUPPLY CURRENT [mA] GROUND CURRENT [mA] 5.0 4.0 3.0 2.0 VIN = 3.6V all LEDs open 1.0 80 1.5x mode 60 40 20 4 LEDs at 15mA 0 0.0 3.0 3.2 3.4 3.6 3.8 4.0 INPUT VOLTAGE [V] 3.0 4.2 4.2 1.10 CLOCK FREQUENCY[MHz] 1.10 CLOCK FREQUENCY [MHz] 3.2 3.4 3.6 3.8 4.0 INPUT VOLTAGE [V] Oscillator Frequency vs. Temperature Oscillator Frequency vs. Input Voltage 1.05 1.00 4 LEDs at 20mA 0.95 0.90 3.0 3.2 3.4 3.6 3.8 4.0 1.05 1.00 0.95 VIN = 3.6V 4 LEDs at 15mA 0.90 4.2 -40 -20 0 20 40 60 80 100 TEMPERATURE [˚C] INPUT VOLTAGE [V] Output Resistance vs. Input Voltage (1.5x mode) Output Resistance vs. Input Voltage (1x mode) 4 ] 10 OUTPUT RESISTANCE ] OUTPUT RESISTANCE 1x mode 3 100mA load 2 1 0 8 100mA load 6 25mA load 4 2 3.0 3.2 3.4 3.6 3.8 4.0 INPUT VOLTAGE [V] © 2005 by Catalyst Semiconductor, Inc. Characteristics subject to change without notice 4.2 3.0 7 3.2 3.4 3.6 3.8 4.0 INPUT VOLTAGE [V] 4.2 Doc. No. 5008, Rev. I CAT3604 TYPICAL CHARACTERISTICS VIN = 3.6V, EN = VIN, CIN = COUT = 1µF, RSET = 24kΩ, TAMB = 25˚C, unless otherwise specified. Switching Waveforms in 1.5x Mode Operating Waveforms in 1x Mode Power Up 4 LEDs at 15mA, Vin = 3V (1.5x Mode) Power Up 4 LEDs at 15mA, Vin = 3.6V (1x Mode) LED Current vs. RSET Line Transient Response in 1x Mode LED CURRENT [mA] 100 10 1 10 Doc. No. 5008, Rev. I 100 RSET [kohm] 1000 8 © 2005 by Catalyst Semiconductor, Inc. Characteristics subject to change without notice CAT3604 TYPICAL CHARACTERISTICS VIN = 3.6V, EN = VIN, CIN = COUT = 1µF, unless otherwise specified. Foldback Current Limiting OUTPUT VOLTAGE [V] 5 1x mode 4 3 2 1 0 0 100 200 300 400 OUTPUT CURRENT [mA] 500 RECOMMENDED LAYOUT When the driver is in the 1.5x charge pump mode, the 1MHz switching frequency operation requires to minimize trace length and impedance to ground on all 4 capacitors. A ground plane should cover the area on the bottom side of the PCB opposite to the IC and the bypass capacitors. Capacitors Cin and Cout require short connection to ground which can be done with multiple vias as shown on Figure 2. A square copper area matches the QFN16 exposed pad (GND) which is connected by a trace to the pin 12 pad (GND). A large via (metalized hole) centered in the square pad provides a low impedance connection to the ground plane on the opposite side of the PCB and allows the heat dissipated by the driver IC to spread out resulting in excellent thermal performance. 4.41 mm 1.95 mm 2.25 mm 0.65 mm 0.76 mm 2.25 mm 0.35 mm Figure 2: PCB Layout © 2005 by Catalyst Semiconductor, Inc. Characteristics subject to change without notice Figure 3: Recommended QFN 16 Package Land Pattern 9 Doc. No. 5008, Rev. I CAT3604 PACKAGE DRAWING AND DIMENSIONS THIN QFN 16-LEAD 4MM X 4MM 4.41 mm 1.95 mm 2.25 mm 4.00+0.10 (S) Recommended Land Pattern 0.65 mm 0.76 mm 2.25 mm PIN 1 INDEX AREA 4.00+0.10 (S) 0.35 mm 0.20 REF. 0.75+0.05 DAP SIZE 2.5 X 2.5 2.10+0.10 2.10+0.10 C0.35 0.55+0.10 0.0-0.05 0.30+0.05 0.65 TYP NOTE: 1. ALL DIMENSIONS ARE IN mm. ANGLES IN DEGREES. 2. COPLANARITY APPLIES TO THE EXPOSED PAD AS WELL AS THE TERMINALS. COPLANARITY SHALL NOT EXCEED 0.08mm. 3. WARPAGE SHALL NOT EXCEED 0.10mm. 1.95 REF. (2x) 4. PACKAGE LENGTH/PACKAGE WIDTH ARE CONSIDERED AS SPECIAL CHARACTERISTIC. (S) Doc. No. 5008, Rev. I 10 © 2005 by Catalyst Semiconductor, Inc. Characteristics subject to change without notice REVISION HISTORY Date Rev. Reason 8/19/2004 A Initial issue 9/21/2004 B Minor Changes 9/22/2004 C Added Green package in all areas 9/29/2004 D Minor Changes 1/4/2005 E Added QFN land pattern (figure 3) 1/21/2005 F Minor Changes 04/15/2005 G Update Features Update Short Circuit Detect/Disable 06/06/2005 H Update Ordering Information 07/15/2005 I Update Basic Operation Copyrights, Trademarks and Patents Trademarks and registered trademarks of Catalyst Semiconductor include each of the following: DPP ™ AE2 ™ MiniPot™ Catalyst Semiconductor has been issued U.S. and foreign patents and has patent applications pending that protect its products. For a complete list of patents issued to Catalyst Semiconductor contact the Company’s corporate office at 408.542.1000. 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Products with data sheets labeled "Advance Information" or "Preliminary" and other products described herein may not be in production or offered for sale. Catalyst Semiconductor advises customers to obtain the current version of the relevant product information before placing orders. Circuit diagrams illustrate typical semiconductor applications and may not be complete. Catalyst Semiconductor, Inc. Corporate Headquarters 1250 Borregas Avenue Sunnyvale, CA 94089 Phone: 408.542.1000 Fax: 408.542.1200 www.caalyst-semiconductor.com Publication #: Revison: Issue date: 5008 I 07/15/05