CAT3606 6-Channel Low Noise Charge Pump White LED Driver FEATURES ■ ■ Drives up to 4 main LEDs and 2 sub LEDs ■ Separate control for main and sub LEDs White LED detect circuitry on all channels ■ Shutdown current less than 1µA ■ Compatible with supply voltage of 3V to 5.5V ■ ■ Power efficiency up to 90% Small ceramic capacitors ■ Soft start and current limiting ■ Short circuit protection ■ 16-lead thin QFN package, 0.8mm max height ■ Output current up to 30mA per LED ■ High-frequency Operation at 1MHz ■ 2 modes of operation 1x and 1.5x APPLICATIONS ■ Cell phone main and sub-display backlight ■ Navigation ■ PDAs ■ Digital Cameras DESCRIPTION (1MHz) provides low noise and allows the use of very small value ceramic capacitors. The CAT3606 controls up to four LEDs for the main display and two LEDs for the sub-display in cellular phones. The device is capable of operating in either 1x (LDO) mode or 1.5x charge pump mode. All LED pin currents are regulated and tightly matched to achieve uniformity of brightness across the LCD backlight. An external resistor (RSET) sets the nominal output current. A “zero” quiescent current mode can be achieved via the chip enable pin EN. The Main and Sub LEDs each have their own dedicated ON/OFF control pins (ENM, ENS). Dimming can be achieved using either a DC voltage to control the RSET pin current, or by applying a PWM signal on the ENM and ENS pins. The device can deliver as much as 20mA per channel during low voltage operation (3V), and 30mA per channel during nominal operation (3.3V). A constant high-frequency switching scheme The device is available in a 16-lead thin QFN package with a max height of 0.8mm. TYPICAL APPLICATION CIRCUIT C1+ C1- C2+ Li-Ion Battery C2- Main Display Sub Display VOUT VIN COUT + CIN - CAT3606 ON/OFF EN ENABLE LED1-4 ENM ENABLE LED5-6 ENS LED1 LED2 LED3 20mA LED4 LED5 RSET RSET © 2005 by Catalyst Semiconductor, Inc. Characteristics subject to change without notice LED6 GND 1 Doc. No. 5009, Rev. B CAT3606 ORDERING INFORMATION Part Number Package Quantity per Reel Package Marking CAT3606HS4 Thin QFN-16 4x4mm 2000 C366 CAT3606HV4 Thin QFN-16 4x4mm Lead Free 2000 G366 PIN CONFIGURATION Top View LED5 LED4 LED3 LED2 16 15 14 13 LED6 1 12 LED1 EN 2 11 C2+ ENM 3 10 C2- ENS 4 9 C1- GND PAD 5 6 RSET VOUT 7 8 VIN C1+ 16-lead Thin QFN (4mm x 4mm) Note: The "exposed pad" under the package must be connected to the ground plane on the PCB. PIN DESCRIPTIONS Pin Number 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 PAD Doc. No. 5009, Rev. B Name LED6 EN ENM ENS RSET VOUT VIN C1+ C1C2C2+ LED1 LED2 LED3 LED4 LED5 GND Function LED6 cathode terminal Enable/shutdown input, active high Enable "main" input for LED1 to LED4, active low Enable "sub" input for LED5 and LED6, active low The LED output current is set by the current sourced out of the RSET pin Charge pump output connected to the LED anodes Supply voltage Bucket capacitor 1 terminal Bucket capacitor 1 terminal Bucket capacitor 2 terminal Bucket capacitor 2 terminal LED 1 cathode terminal LED 2 cathode terminal LED 3 cathode terminal LED 4 cathode terminal LED 5 cathode terminal Ground reference 2 © 2005 by Catalyst Semiconductor, Inc. Characteristics subject to change without notice CAT3606 ABSOLUTE MAXIMUM RATINGS Parameter VIN, VOUT, LEDx voltage Rating -0.3 to 7.0 Unit V EN, ENM, ENS voltage -0.3 to VIN V RSET voltage RSET current Ambient Temperature Range Storage Temperature Range Lead Temperature ESD Ratings Human Body Model (HBM) Machine Model (MM) (note 1) -0.3 to VIN +1 -40 to +85 -65 to +160 300 V mA o C o C o C 2000 200 V V Note 1: Machine model is with 200pF capacitor discharged directly into each pin. RECOMMENDED OPERATING CONDITIONS Parameter VIN Ambient Temperature Range Input/Output/Bucket Capacitors ILED per LED pin IOUT Total Output Current Rating 3.0 to 5.5 -40 to +85 1 +20% typical 0 to 30 0 to 150 Unit V o C µF mA mA 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 1x Mode, No Load 1.5x Mode, No Load VRSET RSET Regulated Voltage ILED Programmed LED Current ILED LED Current Range with 6 LEDs ILED LED Current Range with 4 LEDs ILED-ACC LED Current Accuracy ILED-DEV Min Typ Max Unit 1.17 0.1 0.3 2.6 1.2 1 1 5 1.23 µA mA mA V 30 20 30 mA mA mA mA mA mA % % IRSET = 5µA IRSET = 37µA IRSET = 78µA 3.3 ≤ VIN ≤ 4.5 V 3.0 ≤ VIN ≤ 4.5 V 3.0 ≤ VIN ≤ 4.5V 0.5mA ≤ ILED ≤ 3mA 3mA ≤ ILED ≤ 30mA 2.4 15.0 30.0 LED Channel Matching (ILED - ILEDAVG) / ILEDAVG +3 1x Mode 1.5x Mode, IOUT = 100mA 0.8 1.4 6.5 1.0 2.5 10 1.3 MHz TDROPOUT Output Resistance (Open Loop) Charge Pump Frequency 1x to 1.5x Mode Transition Dropout Delay 0.4 0.6 0.9 ms IEN-CTR Input Leakage Current On Inputs EN, ENM, ENS 1 µA On Inputs EN, ENM, ENS ISC High Detect Threshold Low Detect Threshold Input Current Limit ILIM Maximum Input Current ROUT fOSC VEN-CTR © 2005 by Catalyst Semiconductor, Inc. Characteristics subject to change without notice +15 +5 % Ω Ω VOUT = GND 0.8 0.7 45 1.3 0.4 30 60 V V mA VOUT > 1V 200 400 600 mA 3 Doc. No. 5009, Rev. B CAT3606 BLOCK DIAGRAM C1- 3≤VIN≤4.2V VIN + CIN Battery C1+ C2- C2+ 1x mode (LDO) 1.5x Charge Pump VOUT COUT - Mode Control 1MHz Oscillator EN LED1 LED2 LED3 LED4 1.2V Reference RSET Current Setting 20mA LED5 LED6 Main Sub 6 Current Sink Regulators ENM ENS LED Output Selection GND Figure 1: CAT3606 Functional Block Diagram BASIC OPERATION LED CURRENT SETTING At power-up, the CAT3606 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, to boost the output voltage high enough to achieve the nominal LED current. 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 above sequence 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 Main and Sub display enable pins (ENM or ENS) does not affect the mode of operation. LED Current (mA) RSET (kΩ) 1 649 2 287 5 102 10 49.9 15 32.4 20 23.7 30 15.4 Table 1. RSET Resistor Selection Doc. No. 5009, Rev. B 4 © 2005 by Catalyst Semiconductor, Inc. Characteristics subject to change without notice CAT3606 The enable lines ENM and ENS allow to turn On or Off a group of LEDs as shown in Table 2. Control Lines EN ENM ENS 0 1 1 1 1 X 1 0 1 0 X 1 1 0 0 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 0.2mA. When the following equation is true on any channel, the driver turns off the LED channel: LED Outputs Sub Main LED1 - LED4 LED5 - LED6 ON ON ON ON VOUT - VLED ≤ 1V (LED channel OFF) Note: The CAT3606 is designed to drive LEDs with forward voltage greater than 1V and is not compatible with resistive loads. Table 2: LED Selection Notes: 1 = logic high (or VIN) 0 = logic low (or GND) - = LED output OFF X = don't care © 2005 by Catalyst Semiconductor, Inc. Characteristics subject to change without notice 5 Doc. No. 5009, Rev. B CAT3606 TYPICAL CHARACTERISTICS VIN = 3.6V, EN = VIN, ENM = ENS = GND, CIN = COUT = 1µF, RSET = 24kΩ (20mA per LED), TAMB = 25˚C, unless otherwise specified. Efficiency vs. Input Voltage (6 LEDs) Efficiency vs. Total LED Current (6 LEDs) 100 90 EFFICIENCY [%] EFFICIENCY [%] 100 1x mode 80 1.5x mode 70 60 50 20mA per LED 90 VIN = 4V (1x mode) 80 70 60 VIN = 3.2V (1.5x mode) 50 15mA per LED 40 40 4.2 4.0 3.8 3.6 3.4 3.2 3.0 0 50 LED Current Change vs. Input Voltage LED CURRENT CHANGE [%] LED CURRENT CHANGE [%] 1.0 6 LEDs at 15mA 0.5 0.0 -0.5 -1.0 -1.5 3.4 3.6 3.8 4.0 4 3 6 LEDs at 15mA Vin = 4V 2 1 0 -1 -2 -3 -4 -50 4.2 -25 INPUT VOLTAGE [V] 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] 200 LED Current Change vs. Temperature 1.5 3.2 150 TOTAL LED CURRENT [mA] INPUT VOLTAGE [V] 3.0 100 0.4 0.3 0.2 6 LEDs OFF 0.1 0.0 3.0 3.2 3.4 3.6 3.8 4.0 0.3 0.2 6 LEDs OFF Rset = 500kΩ 0.1 0.0 4.2 -40 INPUT VOLTAGE [V] Doc. No. 5009, Rev. B 0.4 -20 0 20 40 60 80 100 TEMPERATURE [°C] 6 © 2005 by Catalyst Semiconductor, Inc. Characteristics subject to change without notice CAT3606 TYPICAL CHARACTERISTICS VIN = 3.6V, EN = VIN, ENM = ENS = GND, CIN = COUT = 1µF, RSET = 24kΩ (20mA per LED), TAMB = 25˚C, unless otherwise specified. Supply Current vs. Input Voltage 5.0 SUPPLY CURRENT [mA] GROUND CURRENT [mA] Ground Current vs. Input Voltage (1.5x mode) 4.0 3.0 2.0 VIN = 3.6V all LEDs open 1.0 3.2 3.4 3.6 3.8 1.5x mode 120 100 1x mode 6 LEDs at 15mA 80 3.0 0.0 3.0 140 4.0 4.2 3.2 Oscillator Frequency vs. Input Voltage 3.8 4.0 4.2 Oscillator Frequency vs. Temperature 1.10 CLOCK FREQUENCY [MHz] 1.10 CLOCK FREQUENCY [MHz] 3.6 INPUT VOLTAGE [V] INPUT VOLTAGE [V] 1.05 1.00 6 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 6 LEDs at 15mA 0.90 4.2 -40 -20 INPUT VOLTAGE [V] Output Resistance vs. Input Voltage (1x mode) 100 10 OUTPUT RESISTANCE [Ω] 3 100mA load 100mA load 2 1 0 3.0 0 20 40 60 80 TEMPERATURE [°C] Output Resistance vs. Input Voltage (1.5x mode) 4 OUTPUT RESISTANCE [Ω] 3.4 3.2 3.4 3.6 3.8 4.0 6 100mA load 100mA load 4 2 3.0 4.2 INPUT VOLTAGE [V] © 2005 by Catalyst Semiconductor, Inc. Characteristics subject to change without notice 8 3.2 3.4 3.6 3.8 4.0 4.2 INPUT VOLTAGE [V] 7 Doc. No. 5009, Rev. B CAT3606 TYPICAL CHARACTERISTICS VIN = 3.6V, EN = VIN, ENM = ENS = GND, CIN = COUT = 1µF, RSET = 24kΩ (20mA per LED), TAMB = 25˚C, unless otherwise specified. Switching Waveforms in 1.5x Mode Operating Waveforms in 1x Mode Power Up 6 LEDs at 15mA, VIN = 3V (1.5x Mode) Power Up 6 LEDs at 15mA, VIN = 3.6V (1x Mode) LED Current vs. RSET Line Transient Response in 1x Mode LED CURRENT [mA] 100.0 10.0 1.0 0.1 10 100 1000 10000 RSET [kohm] Doc. No. 5009, Rev. B 8 © 2005 by Catalyst Semiconductor, Inc. Characteristics subject to change without notice CAT3606 TYPICAL CHARACTERISTICS VIN = 3.6V, EN = VIN, ENM = ENS = GND, CIN = COUT = 1µF, TAMB = 25˚C, unless otherwise specified. Foldback Current Limiting RSET Pin Voltage vs. Temperature 1.24 RSET PIN VOLTAGE [v] OUTPUT VOLTAGE [v] 5 1x mode 4 3 2 1 0 1.22 1.20 1.18 1.16 0 100 200 300 400 OUTPUT CURRENT [mA] 500 -50 -25 0 25 50 75 100 125 TEMPERATURE [°C] PWM Dimming at 1kHz on ENM and ENS 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) and must be connected to the ground plane underneath. The use of multiple via will improve the heat dissipation. Figure 2: PCB Layout © 2005 by Catalyst Semiconductor, Inc. Characteristics subject to change without notice 9 Doc. No. 5009, Rev. B CAT3606 PACKAGE DRAWING AND DIMENSIONS THIN QFN 16-LEAD 4MM X 4MM Recommended Land Pattern 4.41 mm 1.95 mm 2.25 mm 4.00+0.10 (S) 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 NOTE: 1. ALL DIMENSIONS ARE IN mm. ANGLES IN DEGREES. C0.35 0.55+0.10 0.0-0.05 0.30+0.05 0.65 TYP 3. WARPAGE SHALL NOT EXCEED 0.10mm. 4. PACKAGE LENGTH/PACKAGE WIDTH ARE CONSIDERED AS SPECIAL CHARACTERISTIC. (S) 1.95 REF. (2x) Doc. No. 5009, Rev. B 2. COPLANARITY APPLIES TO THE EXPOSED PAD AS WELL AS THE TERMINALS. COPLANARITY SHALL NOT EXCEED 0.08mm. 10 © 2005 by Catalyst Semiconductor, Inc. Characteristics subject to change without notice REVISION HISTORY Date Rev. Reason 1/21/2005 A Initial issue 08/01/2005 B Update LED Current Setting 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. 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 1250 Borregas Avenue Sunnyvale, CA 94089 Phone: 408.542.1000 Fax: 408.542.1200 www.caalyst-semiconductor.com Publication #: Revison: Issue date: 5009 B 08/01/05