CAT3612 Programmable 300mA Camera Flash LED Driver FEATURES PRODUCT DESCRIPTION Dual matched regulated LED channels 300mA output current (150mA per channel) 1-wire EZDimTM Programmable LED Current 32 accurate dimming levels Power efficiency up to 90% 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 12-lead TDFN 3mm x 3mm package The CAT3612 is a high-efficiency 1x/1.5x fractional charge pump with programmable current in two LED channels. Each channel delivers accurate regulated current up to 150mA and make CAT3612 ideal for driving one or two flash LEDs. Low noise operation 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 90%, and is ideal for Li-Ion battery powered devices. APPLICATION The EN/DIM logic input provides a 1-wire EZDimTM interface for dimming control of the LEDs. When enabled, pulsing the EN/DIM reduces the LED current on each negative edge in 31 linear steps from 150mA down to zero current. Camera Flash Cellular Phones Digital Still Cameras ORDERING INFORMATION Part Number Package The device is available in the tiny 12-lead thin DFN 3mm x 3mm package with a max height of 0.8mm. Quantity Package per Reel Marking CAT3612HV2-T2 TDFN-12 3x3 Green * 2000 HAAD Note *: Plated lead finish is Matte Tin. For other lead finish option, please contact factory. PIN CONFIGURATION TYPICAL APPLICATION CIRCUIT Top View 12-lead TDFN 3mm x 3mm Note: Unused LED channel must be connected to VOUT © 2006 Catalyst Semiconductor, Inc. Characteristics subject to change without notice 1 Doc. No. 5016 Rev. A CAT3612 ABSOLUTE MAXIMUM RATINGS Parameter VIN, LED1, LED2 voltage VOUT, C1±, C2± voltage EN/DIM voltage Storage Temperature Range Junction Temperature Range Lead Temperature Rating 6 7 VIN + 0.7V -65 to +160 -40 to +125 300 Unit V V V °C °C °C RECOMMENDED OPERATING CONDITIONS Parameter VIN Ambient Temperature Range ILED per LED pin Total Output Current Range 3 to 5.5 -40 to +85 0 to 150 0 to 300 Unit V °C mA mA Typical application circuit with external components is shown on page 1. ELECTRICAL OPERATING CHARACTERISTICS (over recommended operating conditions unless specified otherwise) VIN = 3.6V, EN = High, ambient temperature of 25ºC. Symbol Parameter IQ Quiescent Current IQSHDN ILED-ACC ILED-DEV ROUT Shutdown Current LED Current Accuracy LED Channel Matching Output Resistance (open loop) FOSC ISC_MAX IIN_MAX Charge Pump Frequency Output short circuit Current Limit Input Current Limit EN/DIM Pin • Input Leakage • Logic High Level • Logic Low Level Thermal Shutdown Thermal Hysteresis Undervoltage lock out (UVLO) Threshold IEN/DIM VHI VLO TSD THYS VUVLO Doc. No. 5016 Rev. A Conditions 1x mode, no load 1.5x mode, no load VEN = 0V 5mA ≤ ILED ≤ 150mA (ILED - ILEDAVG) / ILEDAVG 1x mode, IOUT = 100mA 1.5x mode, IOUT = 100mA Min Typ 0.5 3 Max 1 0.8 VOUT < 0.5V 1x mode, VOUT > 1V ±3 ±3 0.4 2.6 1 60 350 -1 1.3 1.3 1 0.4 165 20 2 2 Unit mA mA µA % % Ω Ω MHz mA mA µA V V ºC ºC V © 2006 Catalyst Semiconductor, Inc. Characteristics subject to change without notice CAT3612 RECOMENDED EN/DIM TIMING For 3V ≤ VIN ≤ 5.5V, over full ambient temperature range -40°C to +85°C. Symbol TSETP TLO THI TOFF TD TDEC Parameter EN/DIM setup from shutdown EN/DIM program low time EN/DIM program high time EN/DIM low time to shutdown LED current enable LED current decrement Conditions Min 10 0.3 0.3 1.5 Typ Max 200 40 0.1 Unit µs µs µs ms µs µs Figure 1. LED Dimming Timing Diagram © 2006 Catalyst Semiconductor, Inc. Characteristics subject to change without notice 3 Doc. No. 5016 Rev. A CAT3612 TYPICAL CHARACTERISTICS VIN = 3.6V, IOUT = 100mA, CIN = COUT = 2.2µF, C1 = C2 = 1µF, TAMB = 25°C unless otherwise specified. Efficiency vs. LED Current Efficiency vs. Input Voltage 100 100 EFFICIENCY [%] 90 VF = 3V 80 70 60 IOUT = 250mA 50 40 4.0 3.8 3.6 3.4 3.2 INPUT VOLTAGE [V] 60 VIN = 3.2V (1.5x Mode) 50 100 150 200 250 LED CURRENT [mA] 300 Quiescent Current vs. Temperature (1x mode) 0.8 QUIESCENT CURRENT [mA] 0.8 QUIESCENT CURRENT [mA] 70 40 3.0 Quiescent Current vs. Input Voltage (1x mode) 0.6 0.4 0.2 LED Off 0.0 3.0 3.2 3.4 3.6 3.8 4.0 INPUT VOLTAGE [V] 0.6 0.4 0.2 LED Off 0.0 -40 4.2 Quiescent Current vs. Input Voltage (1.5x mode) 0 40 80 TEMPERATURE [°C] 120 Quiescent Current vs. Temperature (1.5x mode) 6.0 6.0 QUIESCENT CURRENT [mA] QUIESCENT CURRENT [mA] 80 50 IOUT = 100mA 4.2 VIN = 4.2V (1x Mode) 90 EFFICIENCY [%] VF = 3.4V 5.0 4.0 3.0 2.0 1.0 LED Off 0.0 3.0 Doc. No. 5016 Rev. A 3.2 3.4 3.6 3.8 4.0 INPUT VOLTAGE [V] 5.0 4.0 3.0 2.0 1.0 LED Off 0.0 -40 4.2 4 0 40 80 TEMPERATURE [°C] 120 © 2006 Catalyst Semiconductor, Inc. Characteristics subject to change without notice CAT3612 TYPICAL CHARACTERISTICS VIN = 3.6V, IOUT = 100mA, CIN = COUT = 2.2µF, C1 = C2 = 1µF, TAMB = 25°C unless otherwise specified. LED Current Change vs. Temperature 5.0 4.0 3.0 2.0 1.0 0.0 -1.0 -2.0 -3.0 -4.0 -5.0 LED CURRENT CHANGE [%] LED CURRENT CHANGE [%] LED Current Change vs. Input Voltage 1x Mode 1.5x Mode 3.0 3.2 3.4 3.6 3.8 4.0 INPUT VOLTAGE [V] 4.2 -40 Oscillator Frequency vs. Input Voltage 120 1.3 CLOCK FREQUENCY [MHz] CLOCK FREQUENCY [MHz] 0 40 80 TEMPERATURE [°C] Oscillator Frequency vs. Temperature 1.3 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] 1.2 1.1 1.0 0.9 0.8 0.7 -40 4.0 0 40 80 TEMPERATURE [°C] 120 Output Resistance vs. Input Voltage(1.5x mode) Output Resistance vs. Input Voltage (1x mode) 1.0 4.0 OUTPUT RESISTANCE [Ω] . OUTPUT RESISTANCE [Ω] . 5.0 4.0 3.0 2.0 1.0 0.0 -1.0 -2.0 -3.0 -4.0 -5.0 0.8 0.6 0.4 0.2 0.0 3.0 3.2 3.4 3.6 3.8 4.0 INPUT VOLTAGE [V] © 2006 Catalyst Semiconductor, Inc. Characteristics subject to change without notice 4.2 3.5 3.0 2.5 2.0 1.5 1.0 3.0 5 3.2 3.4 3.6 3.8 4.0 INPUT VOLTAGE [V] 4.2 Doc. No. 5016 Rev. A CAT3612 TYPICAL CHARACTERISTICS VIN = 3.6V, IOUT = 100mA, CIN = COUT = 2.2µF, C1 = C2 = 1µF, TAMB = 25°C unless otherwise specified. Power Up with 1 LED at 100mA (1x Mode) Power Up with 1 LED at 100mA (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. 5016 Rev. A 6 © 2006 Catalyst Semiconductor, Inc. Characteristics subject to change without notice CAT3612 TYPICAL CHARACTERISTICS VIN = 3.6V, IOUT = 100mA, CIN = COUT = 2.2µF, C1 = C2 = 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 40 80 120 TEMPERATURE [°C] Foldback Current Limit Enable Voltage Threshold vs. Temperature 1.2 4.0 1.0 3.5 OUTPUT VOLTAGE [V] EN A B LE V OLTA G E [V ] 0 0.8 0.6 0.4 0.2 0.0 3.0 1x Mode LED Off 2.5 2.0 1.5 1.0 0.5 0.0 -40 0 40 80 120 0 TEMPERATURE [°C] © 2006 Catalyst Semiconductor, Inc. Characteristics subject to change without notice 7 100 200 300 400 OUTPUT CURRENT [mA] 500 Doc. No. 5016 Rev. A CAT3612 PIN DESCRIPTIONS Pin # 1 2 3 4 5 6 7 8 9 10 11 12 TAB Name VIN C1+ C1C2GND LED1 LED2 C2+ EN/DIM VOUT TAB Function Supply voltage. Bucket capacitor 1 terminal Bucket capacitor 1 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. Bucket capacitor 2 terminal Not connected Device enable (active high) and dimming control input. Not connected Charge pump output connected to the LED anodes. Connect to GND on the PCB. Note 1: LED1, LED2 pins should not be left floating. They should be connected to the LED cathode, or tied to the VOUT pin if not used. PIN FUNCTION 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. VIN is the supply pin for the device. A small 1µF ceramic bypass capacitor is required between the VIN pin and ground near the device. The operating input voltage range is up to 5.5V. When the input supply falls below the undervoltage threshold (2V), all LEDs channels are disabled. 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 the LED currents remain at 0mA. The falling edge of the first pulse on EN/DIM sets the LED currents to the full scale 150mA. 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, LED2 provide the internal regulated current for each of the LED cathodes. These pins enter a high impedance zero current state whenever the device is in shutdown mode. In applications using only one LED channel, the unused channel should be tied directly to VOUT. The disabled channel only draws about 0.5mA. On each consecutive falling edge of the pulse on EN/DIM, the LED current decreases by 150/31mA. On the 32nd pulse, the LED current is set to zero. The next pulse on EN/DIM resets the current back to full scale 150mA. 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. Doc. No. 5016 Rev. A 8 © 2006 Catalyst Semiconductor, Inc. Characteristics subject to change without notice CAT3612 BLOCK DIAGRAM Figure 2. CAT3612 Functional Block Diagram BASIC OPERATION At power-up, the CAT3612 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 LEDs 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 of 400µs) into 1.5x mode. © 2006 Catalyst Semiconductor, Inc. Characteristics subject to change without notice 9 Doc. No. 5016 Rev. A CAT3612 LED Current Setting Table 1. Selection of LED current per Channel Figure 1 shows the EN/DIM input timing diagram 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 150mA to zero with nearly 5mA resolution. The selection of the LED current per channel is shown in Table 1. 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 CAT3612 enters the shutdown mode and draws “zero” current. Number of pulses on EN/DIM 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 For applications with a single LED connected to one LED pin only, the unused LED pin must be tied to VOUT, as shown on Figure 3. Figure 3. Single LED on one LED pin LED current (mA) 150 145 140 135.5 131 126 121 116 111 106.5 101.5 97 92 87 82 77.5 72.5 68 63 58 53 48.5 43.5 39 34 29 24 19 14.5 10 5 0 Figure 4. Application with 2 LEDs Doc. No. 5016 Rev. A 10 © 2006 Catalyst Semiconductor, Inc. Characteristics subject to change without notice CAT3612 Protection mode Recommended Layout 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. 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 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. 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. 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. Figure 5. Recommended Layout © 2006 Catalyst Semiconductor, Inc. Characteristics subject to change without notice 11 Doc. No. 5016 Rev. A CAT3612 PACKAGE DRAWING AND DIMENSIONS Thin DFN 12-Lead 3mm x 3mm, 0.45mm Pitch RECOMMENDED LAND PATTERN Dimensions in millimeters Doc. No. 5016 Rev. A 12 © 2006 Catalyst Semiconductor, Inc. Characteristics subject to change without notice REVISION HISTORY Date 07/21/2006 Rev. A Reason Initial Issue Copyrights, Trademarks and Patents Trademarks and registered trademarks of Catalyst Semiconductor include each of the following: DPP ™ AE2 ™ 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 www.catsemi.com Document No: 5016 Revision: A Issue date: 07/21/2006