CAT3614 4-Channel 1-Wire LED Driver in 3 x 3mm Package FEATURES DESCRIPTION The CAT3614 is a high efficiency 1x/1.5x fractional charge pump with programmable dimming current in four LED channels. To ensure uniform brightness in LCD backlight applications, each LED channel delivers an accurate regulated current. Drives up to 4 LED channels 1-wire EZDimTM Programmable LED Current Accurate 1mA Dimming Level Power efficiency up to 91% Fractional pump 1x/1.5x Low noise input ripple Fixed High Frequency Operation 1MHz “Zero” Current Shutdown Mode Soft start and current limiting Short circuit protection Thermal shutdown protection TDFN 12-pad 3mm x 3mm package Low noise and input ripple is achieved by operating at a constant switching frequency of 1MHz which allows the use of small external ceramic capacitors. The 1x/1.5x fractional charge pump supports a wide range of input voltages from 3V to 5.5V with efficiency up to 91%, and is ideal for Li-Ion battery powered devices. TM The EN/DIM logic input provides a 1-wire EZDim interface for dimming control of the LEDs. When enabled, a series of clock pulses reduces the LED brightness in 1mA steps on each negative going edge. Currents from 0mA to 31mA are supported. APPLICATIONS LCD Display Backlight Cellular Phones Digital Still Cameras Handheld Devices The device is available in the tiny 12-pad TDFN 3 x 3mm package with a max height of 0.8mm. ORDERING INFORMATION Quantity Part Number Package per Reel CAT3614HV2-T2 TDFN-12 (1) 2000 (2) CAT3614HV2-GT2 TDFN-12 2000 Package Marking HAAA HAAC For Ordering Information details, see page 12. Notes: (1) Matte-Tin Plated Finish (RoHS-compliant). (2) NiPdAu Plated Finish (RoHS-compliant). PIN CONFIGURATION TYPICAL APPLICATION CIRCUIT TDFN 12-Pad 3 x 3mm (Top View) VIN 1 12 VOUT C1+ 2 11 EN/DIM C1- 3 10 LED4 C2- 4 9 LED3 C2+ 5 8 LED2 GND 6 7 LED1 1µF VIN 3V to CIN 5.5V 1µF C1+ C1- C2+ VIN 1µF C2VOUT VOUT COUT 1µF CAT3614 LED1 LED2 ENABLE/ DIMMING 20mA LED3 EN/DIM GND LED4 Note: Unused LED channels must be connected to VOUT. © Catalyst Semiconductor, Inc. Characteristics subject to change without notice 1 Doc. No. MD-5035, Rev.B CAT3614 ABSOLUTE MAXIMUM RATINGS Parameter Rating Unit VIN, LEDx voltage 6 V VOUT, C1±, C2± voltage 7 V EN/DIM voltage VIN + 0.7V V Storage Temperature Range -65 to +160 °C Junction Temperature Range -40 to +150 °C 300 °C Lead Temperature RECOMMENDED OPERATING CONDITIONS Parameter Range Unit VIN 3 to 5.5 V -40 to +85 °C ILED per LED pin 0 to 31 mA Total Output Current 0 to 124 mA Ambient Temperature Range Typical application circuit with external components is shown on page 1. ELECTRICAL OPERATING CHARACTERISTICS VIN = 3.6V, EN = High, ambient temperature of 25ºC (over recommended operating conditions unless specified otherwise). Symbol Parameter Conditions Min Typ Max Unit 0.3 1 0.5 3 1 8 mA mA 1 µA IQ Quiescent Current 1x mode, no load 1.5x mode, no load IQSHDN Shutdown Current VEN = 0V ILED-ACC LED Current Accuracy 1mA ≤ ILED ≤ 31mA ±3 ±8 % ILED-DEV LED Channel Matching (ILED - ILEDAVG) / ILEDAVG ±3 ±7 % ROUT Output Resistance (open loop) 1x mode, IOUT = 100mA 1.5x mode, IOUT = 100mA 0.4 2.6 1 7 Ω Ω FOSC Charge Pump Frequency 0.8 1 1.3 MHz ISC_MAX Output short circuit Current Limit VOUT < 0.5V 30 60 100 mA IIN_MAX Input Current Limit 1x mode, VOUT > 1V 200 300 600 mA IEN/DIM VHI VLO 1 0.4 µA V V TSD EN/DIM Pin • Input Leakage • Logic High Level • Logic Low Level Thermal Shutdown 145 165 175 ºC THYS Thermal Hysteresis 10 20 30 ºC VUVLO Undervoltage lock out (UVLO) threshold 1.7 2 2.4 V Doc. No. MD-5035, Rev.B -1 1.3 2 © Catalyst Semiconductor, Inc. Characteristics subject to change without notice CAT3614 RECOMMENDED EN/DIM TIMING For 3V ≤ VIN ≤ 5.5V, over full ambient temperature range -40 to +85ºC. Symbol Parameter TSETP Conditions Min Typ Max Unit EN/DIM setup from shutdown 10 TLO EN/DIM program low time 0.3 THI EN/DIM program high time 0.3 µs EN/DIM low time to shutdown 1.5 ms TOFF TD TDEC µs 200 µs LED current enable 40 µs LED current decrement 0.1 µs TSETP THI TOFF EN/DIM TD TLO TDEC 31mA 31mA 30mA 29mA LED Current Shutdown 1mA 0mA Shutdown Figure 1. LED Dimming Timing Diagram © Catalyst Semiconductor, Inc. Characteristics subject to change without notice 3 Doc. No. MD-5035, Rev.B CAT3614 TYPICAL CHARACTERISTICS VIN = 3.6V, IOUT = 80mA (4 LEDs at 20mA), C1 = C2 = CIN = COUT = 1μF, TAMB = 25°C unless otherwise specified. Efficiency vs. Total LED Current (4 LEDs) Efficiency vs. Input Voltage (4 LEDs) 100 100 20mA per LED 90 1x mode EFFICIENCY [%] EFFICIENCY [%] 90 80 70 10mA per LED 60 50 70 60 VIN = 3.2V (1.5x mode) 40 4.2 4.0 3.8 3.6 3.4 3.2 INPUT VOLTAGE [V] 0 3.0 25 50 75 100 125 TOTAL LED CURRENT [mA] Quiescent Current vs. Temperature (1x mode) Quiescent Current vs. Input Voltage (1x mode) 0.8 QUIESCENT CURRENT [mA] 0.8 QUIESCENT CURRENT [mA] . 80 50 1.5x mode 40 0.6 0.4 4 LEDs OFF 0.2 0.6 0.4 4 LEDs OFF 0.2 0.0 0.0 3.0 3.2 3.4 3.6 3.8 4.0 INPUT VOLTAGE [V] -40 4.2 0 40 80 TEMPERATURE [°C] 120 Quiescent Current vs. Temperature (1.5x mode) Quiescent Current vs. Input Voltage (1.5x mode) 6.0 6.0 QUIESCENT CURRENT [mA] QUIESCENT CURRENT [mA] . VIN = 4V (1x mode) 5.0 4.0 3.0 2.0 4 LEDs OFF 1.0 0.0 3.0 3.2 3.4 3.6 3.8 4.0 4.0 3.0 2.0 4 LEDs OFF 1.0 0.0 4.2 -40 INPUT VOLTAGE [V] Doc. No. 8755 Rev. A 5.0 4 0 40 80 TEMPERATURE [°C] 120 © 2005 Catalyst Semiconductor, Inc. Characteristics subject to change without notice CAT3614 TYPICAL CHARACTERISTICS VIN = 3.6V, IOUT = 80mA (4 LEDs at 20mA), C1 = C2 = CIN = COUT = 1μF, TAMB = 25°C unless otherwise specified. LED Current Change vs. Temperature 5.0 5.0 4.0 3.0 4.0 2.0 1.0 LED CURRENT CHANGE [%] LED CURRENT CHANGE [%] . LED Current Change vs. Input Voltage 1x Mode 0.0 -1.0 -2.0 1.5x Mode -3.0 -4.0 3.0 2.0 1.0 0.0 -1.0 -2.0 -3.0 -4.0 -5.0 -5.0 3.0 3.2 3.4 3.6 3.8 4.0 4.2 -40 INPUT VOLTAGE [V] Oscillator Frequency vs. Input Voltage 80 1.3 CLOCK FREQUENCY [MHz] CLOCK FREQUENCY [MHz] 0 20 40 60 TEMPERATURE [°C] Oscillator Frequency vs. Temperature 1.3 1.2 1.1 1.0 4 LEDs at 20mA 0.9 0.8 0.7 1.2 1.1 1.0 0.9 0.8 0.7 3.0 3.2 3.4 3.6 3.8 INPUT VOLTAGE [V] 4.0 -40 0 40 80 TEMPERATURE [°C] 120 Output Resistance vs. Input Voltage (1.5x mode) 4.0 Output Resistance vs. Input Voltage (1x mode) OUTPUT RESISTANCE [Ω] . 1.0 OUTPUT RESISTANCE [Ω] . -20 0.8 0.6 0.4 0.2 3.5 3.0 2.5 2.0 1.5 1.0 0.0 3.0 3.2 3.4 3.6 3.8 4.0 INPUT VOLTAGE [V] © 2005 Catalyst Semiconductor, Inc. Characteristics subject to change without notice 3.0 4.2 5 3.2 3.4 3.6 3.8 4.0 INPUT VOLTAGE [V] 4.2 Doc. No. 8755 Rev. A CAT3614 TYPICAL CHARACTERISTICS VIN = 3.6V, IOUT = 80mA (4 LEDs at 20mA), C1 = C2 = CIN = COUT = 1μF, TAMB = 25°C unless otherwise specified. Power Up with 4 LEDs at 15mA (1x Mode) Power Up with 4 LEDs at 15mA (1.5x Mode) Enable Power Down Delay (1x Mode) Enable Power Down Delay (1.5x Mode) Switching Waveforms in 1.5x Mode Operating Waveforms in 1x Mode Doc. No. 8755 Rev. A 6 © 2005 Catalyst Semiconductor, Inc. Characteristics subject to change without notice CAT3614 TYPICAL CHARACTERISTICS VIN = 3.6V, IOUT = 80mA (4 LEDs at 20mA), C1 = C2 = CIN = COUT = 1μF, TAMB = 25°C unless otherwise specified. Enable and Output Current Dimming Waveforms Line Transient Response (3.6V to 5.5V) 1x Mode Enable High Minimum Program Time vs. Temperature Enable Low Minimum Program Time vs. Temperature 200 200 MINIMUM TIME [nS] . MINIMUM TIME [nS] . VIN = 3.5V 160 VIN = 3.5V 120 80 VIN = 4.2V 40 160 120 VIN = 4.2V 80 40 0 0 -40 0 40 80 TEMPERATURE [°C] -40 120 0 80 120 TEMPERATURE [°C] Foldback Current Limit Enable Voltage Threshold vs. Temperature 4.0 1.2 1.0 OUTPUT VOLTAGE [V] ENABLE VOLTAGE [V] 40 0.8 0.6 0.4 0.2 0.0 3.5 3.0 1x Mode 2.5 VIN = 3.5V 2.0 1.5 1.0 0.5 0.0 -40 0 40 80 120 0 TEMPERATURE [°C] © 2005 Catalyst Semiconductor, Inc. Characteristics subject to change without notice 7 100 200 300 OUTPUT CURRENT [mA] 400 Doc. No. 8755 Rev. A CAT3614 PIN DESCRIPTIONS Pin # 1 2 3 4 5 6 7 8 9 10 11 12 TAB Name VIN C1+ C1C2C2+ GND LED1 LED2 LED3 LED4 EN/DIM VOUT TAB Function Supply voltage. Bucket capacitor 1 terminal Bucket capacitor 1 terminal Bucket capacitor 2 terminal Bucket capacitor 2 terminal Ground reference LED1 cathode terminal (if not used, connect to VOUT) (1) LED2 cathode terminal (if not used, connect to VOUT)(1) LED3 cathode terminal (if not used, connect to VOUT)(1) LED4 cathode terminal (if not used, connect to VOUT)(1) Device enable (active high) and dimming control input Charge pump output connected to the LED anodes Connect to GND on the PCB PIN FUNCTION VIN is the supply pin for the charge pump. A small 1µF ceramic bypass capacitor is required between the VIN pin and ground near the device. The operating input voltage range is from 2.2V to 5.5V. Whenever the input supply falls below the undervoltage threshold (2V) all LEDs channels will be automatically disabled. VOUT is the charge pump output that is connected to the LED anodes. A small 1µF 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. EN/DIM is the enable and dimming control logic input for all LED channels. Guaranteed levels of logic high and logic low are set at 1.3V and 0.4V respectively. When EN/DIM is initially taken high, the device becomes enabled and all LED currents remain at 0mA. The falling edge of the first pulse applied to EN/DIM sets all LED currents to their full scale of 31mA. C1+, C1- are connected to each side of the 1µF ceramic bucket capacitor C1. C2+, C2- are connected to each side of the 1µF ceramic bucket capacitor C2. LED1 to LED4 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 four LEDs, all unused channels should be wired directly to VOUT. This ensures the channel is automatically disabled dissipating less than 200µA. On each consecutive falling edge of the pulse applied to EN/DIM, the LED current is decreased by 1mA step. On the 32nd pulse, the LED current is set to zero. The next pulse on EN/DIM resets the current back to their full scale of 31mA. 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. To place the device into zero current shutdown mode, the EN/DIM pin must be held low for 1.5ms or more. Notes: (1) LED1, LED2, LED3, LED4 pins should not be left floating. They should be connected to the LED cathode, or tied to VOUT pin if not used. Doc. No. MD-5035, Rev.B 8 © Catalyst Semiconductor, Inc. Characteristics subject to change without notice CAT3614 BLOCK DIAGRAM 1µF C1- VIN C1+ C2- 1µF C2+ VOUT 1x mode (LDO) 1.5x Charge Pump CIN 1µF Mode Control 1MHz Oscillator EN/DIM LED1 LED2 Reference Voltage LED3 LED4 Current Setting DAC LED Channel Current Regulators Serial Interface Registers GND Figure 2. CAT3614 Functional Block Diagram BASIC OPERATION At power-up, the CAT3614 starts operating in 1x mode where the output will be approximately equal to the input supply voltage (less any internal voltage losses). If the output voltage is sufficient to regulate all LED currents the device remains in 1x operating mode. In 1.5x mode, the output is approximately equal to 1.5 times the input supply voltage (less any internal voltage losses). The above sequence is repeated each and every time the chip is powered-up or is taken out of shutdown mode (via EN/DIM pin). If the input voltage is insufficient or falls to a level where the regulated currents cannot be maintained, the device automatically switches (after a fixed delay of 400µs) into 1.5x mode. © Catalyst Semiconductor, Inc. Characteristics subject to change without notice 9 Doc. No. MD-5035, Rev.B CAT3614 The driver enters a thermal shutdown mode as soon as the die temperature exceeds about +165ºC. When the device temperature drops down by about 20ºC, the device resumes normal operation. LED Current Setting Figure 1 shows the timing diagram necessary at the EN/DIM input for setting the LED currents. The EN/DIM set up time requires the signal to be held high for 10µs or longer to ensure the initialization of the driver at power-up. Each subsequent pulse on the EN/DIM (300ns to 200µs pulse duration) steps down the LED current from full scale of 31mA to zero with a 1mA resolution. Consecutive pulses should be separated by 300ns or longer. Pulsing beyond the 0mA level restores the current level back to full scale and the cycle repeats. Pulsing frequencies from 5kHz up to 1MHz can be supported during dimming operations. When the EN/DIM is held low for 1.5ms or more, the CAT3614 enters the shutdown mode and draws “zero” current. External Components The driver requires a total of four external 1µF 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 1µF 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 1MHz. 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 vias. A copper area matching the TDFN exposed pad (GND) must be connected to the ground plane underneath. The use of multiple vias improves the package heat dissipation. For applications with three LEDs or less, any unused LED pins should be tied to VOUT, as shown on Figure 3. Protection Mode If an LED becomes open-circuit, the output voltage VOUT is internally limited to about 5.5V. This is to prevent the output pin from exceeding its absolute maximum rating. 1µF VIN 3V to CIN 5.5V 1µF C1+ C1- C2+ VIN C2- COUT CAT3614 C1+ VIN VOUT LED1 ENABLE/ DIMMING 1µF 1µF 1µF 3V to CIN 5.5V 1µF 1µF C1- C2+ VIN VOUT LED1 ENABLE/ DIMMING LED3 GND LED4 Flash LED 120mA LED2 EN/DIM LED3 GND Figure 3. Three LED Application Doc. No. MD-5035, Rev.B COUT 1µF CAT3614 LED2 EN/DIM C2- LED4 Figure 4. Single Flash LED Application 10 © Catalyst Semiconductor, Inc. Characteristics subject to change without notice CAT3614 PACKAGE OUTLINE DRAWING TDFN 12-Pad 3 x 3mm (HV2) (1)(2) D A e b L E E2 PIN#1 ID PIN#1 INDEX AREA A1 D2 SIDE VIEW TOP VIEW BOTTOM VIEW A A3 SYMBOL 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 e A1 FRONT VIEW RECOMMENDED LAND PATTERN R e M N 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 P E2 2.25 TYP D2 Notes: (1) All dimensions in millimeters. (2) Compiles with JEDEC MO-229. © Catalyst Semiconductor, Inc. Characteristics subject to change without notice 11 Doc. No. MD-5035, Rev.B CAT3614 EXAMPLE OF ORDERING INFORMATION (1) Prefix CAT Device # 3614 Suffix HV2 – Product Number 3614 Optional Company ID G T2 Lead Finish G: NiPdAu Blank: Matte-Tin(4) Tape & Reel T: Tape & Reel 2: 2000/Reel Package HV2: TDFN 3 x 3mm Notes: (1) All packages are RoHS-compliant (Lead-free, Halogen-free). (2) The standard lead finish is NiPdAu. (3) The device used in the above example is a CAT3614HV2-GT2 (TDFN, NiPdAu Plated Finish,Tape & Reel 2000). (4) For additional package, please contact your nearest Catalyst Semiconductor Sales office. Doc. No. MD-5035, Rev.B 12 © Catalyst Semiconductor, Inc. Characteristics subject to change without notice REVISION HISTORY Date Rev. 02/09/2006 00 07/21/2006 01 01/07/08 B Reason Initial Release Update Typical Application Circuit Update Pin Descriptions Update Electrical Operating Characteristics Add NiPdAu lead finish. Add Extended Temperature Range. Update Package Outline Drawing. Add Example of Ordering Information. Change document number from 25095 to MD-5035. Copyrights, Trademarks and Patents © Catalyst Semiconductor, Inc. Trademarks and registered trademarks of Catalyst Semiconductor include each of the following: Adaptive Analog™, Beyond Memory™, DPP™, EZDim™, LDD™, MiniPot™, Quad-Mode™ and Quantum Charge Programmable™ Catalyst Semiconductor has been issued U.S. and foreign patents and has patent applications pending that protect its products. CATALYST SEMICONDUCTOR MAKES NO WARRANTY, REPRESENTATION OR GUARANTEE, EXPRESS OR IMPLIED, REGARDING THE SUITABILITY OF ITS PRODUCTS FOR ANY PARTICULAR PURPOSE, NOR THAT THE USE OF ITS PRODUCTS WILL NOT INFRINGE ITS INTELLECTUAL PROPERTY RIGHTS OR THE RIGHTS OF THIRD PARTIES WITH RESPECT TO ANY PARTICULAR USE OR APPLICATION AND SPECIFICALLY DISCLAIMS ANY AND ALL LIABILITY ARISING OUT OF ANY SUCH USE OR APPLICATION, INCLUDING BUT NOT LIMITED TO, CONSEQUENTIAL OR INCIDENTAL DAMAGES. Catalyst Semiconductor 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 Catalyst Semiconductor product could create a situation where personal injury or death may occur. Catalyst Semiconductor reserves the right to make changes to or discontinue any product or service described herein without notice. 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 2975 Stender Way Santa Clara, CA 95054 Phone: 408.542.1000 Fax: 408.542.1200 0Hwww.catsemi.com Document No: MD-5035 Revision: B Issue date: 01/07/08