CAT3644 4-Channel Ultra High Efficiency Quad-Mode™ LED Driver FEATURES DESCRIPTION High efficiency 1.33x charge pump The CAT3644 is a high efficiency quad-mode fractional charge pump that can drive up to four LEDs programmable by a one wire digital interface. The inclusion of a 1.33x fractional charge pump mode increases device efficiency by up to 10% over tradi– tional 1.5x charge pumps with no added external capacitors. Quad-mode charge pump: 1x, 1.33x, 1.5x, 2x Drives up to 4 LEDs at 25mA each 1-wire EZDim™ LED current programming Power efficiency up to 92% Low noise input ripple in all modes Low noise input ripple is achieved by operating at a constant switching frequency which allows the use of small external ceramic capacitors. The multi-fractional charge pump supports a wide range of input voltages from 2.5V to 5.5V. “Zero” current shutdown mode Soft start and current limiting Short circuit protection Thermal shutdown protection The EN/DIM logic input functions as a chip enable and a digital dimming interface for current setting of all LEDs. Six different current ratios are available via the interface. 3mm x 3mm, 16-lead TQFN package APPLICATION LCD Display Backlight The device is available in the tiny 16-lead TQFN 3mm x 3mm package with a max height of 0.8mm. Cellular Phones Digital Still Cameras The 1.33x charge pump with two fly capacitors is a patent pending architecture exclusive to Catalyst Semiconductor. Handheld Devices ORDERING INFORMATION Part Number Package Marking Package CAT3644HV3-T2 TQFN-16 3x3mm(1) For Ordering Information details, see page 13. JAAG Note: (1) Matte-Tin Plated Finish (RoHS-compliant) TYPICAL APPLICATION CIRCUIT PIN CONFIGURATION LED1 GND NC NC 1µF 16 15 14 13 LED2 1 12 C2- LED3 2 11 C2+ LED4 3 10 C1- RSET 4 9 C1+ 5 6 7 8 EN/DIM VOUT NC VIN © 2007 Catalyst Semiconductor, Inc. Characteristics subject to change without notice C1+ VIN 2.4V to 5.5V CIN 1µF 1-Wire EZDimTM Programming 3.8kΩ 1 C1- C2+ VIN 1µF C2VOUT White LEDs VOUT COUT 1µF CAT3644 LED1 EN/DIM LED2 RSET LED3 GND 20mA LED4 Doc. No. 5023, Rev. B CAT3644 ABSOLUTE MAXIMUM RATINGS Parameter VIN, LEDx, C1±, C2± voltage VOUT voltage EN/DIM voltage Storage Temperature Range Junction Temperature Range Lead Temperature Rating 6 7 6 -65 to +160 -40 to +125 300 Unit V V V °C °C °C Rating 2.5 to 5.5 -40 to +85 0 to 25 0 to 100 1.3 to 4.3 Unit V °C mA mA V RECOMMENDED OPERATING CONDITIONS Parameter VIN Ambient Temperature Range ILED per LED pin Total Output Current LED Forward Voltage Range 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, TAMB = 25°C Symbol Name IQSHDN Shutdown Current Conditions 1x mode, no load 1.33 x mode, no load 1.5x mode, no load 2x mode, no load VEN = 0V ILED-ACC LED Current Accuracy ILEDAVG / ILEDAVG-NOMINAL ±2 % ILED-DEV LED Channel Matching (ILED - ILEDAVG) / ILEDAVG ±1.5 % IQ Quiescent Current VRSET RSET Regulated Voltage ROUT Output Resistance (open loop) FOSC Charge Pump Frequency ISC_MAX Output short circuit Current Limit IIN_MAX LEDTH VHYS Input Current Limit 1x to 1.33x or 1.33x to 1.5x or 1.5x to 2x Transition Thresholds at any LED pin 1x Mode Transition Hysteresis TDF Transition Filter Delay REN/DIM VHI VLO Min 0.8 1 VOUT > 1V EN/DIM Pin • Internal Pull-down Resistor • Logic High Level • Logic Low Level Max 1 0.58 1x mode 1.33x mode, VIN = 3V 1.5x mode, VIN = 2.7V 2x mode, VIN = 2.4V 1.33x and 2x mode 1.5x mode VOUT < 0.5V Typ 1.0 1.7 2.2 2.4 0.6 0.8 5 5 10 1 1.3 50 0.62 1.3 1.6 Units mA mA mA mA µA V Ω Ω Ω Ω MHz MHz mA 250 mA 130 400 mV mV 500 µs 100 kΩ V V 1.3 0.4 TSD Thermal Shutdown 150 °C THYS Thermal Hysteresis 20 °C VUVLO Undervoltage lockout (UVLO) threshold Doc. No. 5023, Rev. B 1.6 2 1.8 2.0 V © 2007 Catalyst Semiconductor, Inc. Characteristics subject to change without notice CAT3644 RECOMMENDED EN/DIM TIMING For 2.4V ≤ VIN ≤ 5.5V, over full ambient temperature range -40ºC to +85ºC. Symbol Name Conditions TSETUP EN/DIM setup from shutdown 10 TLO EN/DIM program low time 0.2 THI EN/DIM program high time 0.2 μs TPWRDWN EN/DIM low time to shutdown 1.5 ms TLED LED current settling time TSETUP Min Typ Max Units μs 100 40 μs μs TPWRDWN THI EN/DIM TLED TLO 100% 100% 50% LED Current Shutdown 25% 12.5% 6.25% 3.12% Shutdown Figure 1. EN/DIM Digital Dimming Timing Diagram © 2007 Catalyst Semiconductor, Inc. Characteristics subject to change without notice 3 Doc. No. 5023, Rev. B CAT3644 TYPICAL PERFORMANCE CHARACTERISTICS VIN = 3.6V, IOUT = 80mA (4 LEDs at 20mA), CIN = COUT = C1 = C2 = 1μF, TAMB = 25°C unless otherwise specified. Efficiency vs. Input Voltage 100 VF = 3.3V Efficiency vs. Li-Ion Voltage 100 1.33x 1.5x 90 90 EFFICIENCY [%] EFFICIENCY [%] 1x 80 2x 70 60 40 4.2 2.0 QUIESCENT CURRENT [mA] VF = 3.3V 3.0 2.0 1.0 LEDs Off 0.0 2x 1.5x 3.0 2.0 1.33x 1.0 1x 0.0 -40 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 INPUT VOLTAGE [V] 0 40 80 TEMPERATURE [°C] 120 LED Current Change vs. Temperature LED CURRENT VARIATION [%] . LED Current Change vs. Input Voltage LED CURRENT VARIATION [%] . 3.0 4.0 4.0 VF = 3.3V 10 8 6 4 2 VF = 3.3V 0 -2 -4 -6 -8 -10 -40 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 INPUT VOLTAGE [V] Doc. No. 5023, Rev. B 4.0 3.8 3.6 3.4 3.2 INPUT VOLTAGE [V] Quiescent Current vs. Temperature Quiescent Current vs. Input Voltage QUIESCENT CURRENT [mA] 60 40 10 8 6 4 2 0 -2 -4 -6 -8 -10 1.33x 70 50 4.0 3.5 3.0 2.5 INPUT VOLTAGE [V] 1x 80 50 4.5 VF = 3.3V 4 0 40 80 TEMPERATURE [°C] 120 © 2007 Catalyst Semiconductor, Inc. Characteristics subject to change without notice CAT3644 TYPICAL PERFORMANCE CHARACTERISTICS VIN = 3.6V, IOUT = 80mA (4 LEDs at 20mA), CIN = COUT = C1 = C2 = 1μF, TAMB = 25°C unless otherwise specified. Output Resistance vs. Input Voltage 12 1.3 1.2 OUTPUT RESISTANCE [Ω] . SWITCHING FREQUENCY [MHz] Switching Frequency vs. Temperature 1.5x Mode 1.1 1.0 0.9 1.33x, 2x Mode 0.8 0.7 -40 0 40 80 TEMPERATURE [°C] 2x 10 8 6 4 2 1.33x 1.5x 1x 0 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 INPUT VOLTAGE [V] 120 Power Up in 1x Mode Power Up in 1.33x Mode Power Up in 1.5x Mode Power Up in 2x Mode © 2007 Catalyst Semiconductor, Inc. Characteristics subject to change without notice 5 Doc. No. 5023, Rev. B CAT3644 TYPICAL PERFORMANCE CHARACTERISTICS VIN = 3.6V, IOUT = 80mA (4 LEDs at 20mA), CIN = COUT = C1 = C2 = 1μF, TAMB = 25°C unless otherwise specified. Power Up Delay (1x Mode) Doc. No. 5023, Rev. B Power Down Delay (1x Mode) Operating Waveforms in 1x Mode Switching Waveforms in 1.33x Mode Switching Waveforms in 1.5x Mode Switching Waveforms in 2x Mode 6 © 2007 Catalyst Semiconductor, Inc. Characteristics subject to change without notice CAT3644 TYPICAL PERFORMANCE CHARACTERISTICS VIN = 3.6V, IOUT = 80mA (4 LEDs at 20mA), CIN = COUT = C1 = C2 = 1μF, TAMB = 25°C unless otherwise specified. LED Current vs. LED Pin Voltage Foldback Current Limit 40 1x Mode 3.5 LED CURRENT [mA] OUTPUT VOLTAGE [V] 4.0 3.0 2.5 2.0 1.5 1.0 0.5 0.0 30 20 10 0 0 100 200 300 OUTPUT CURRENT [mA] 400 0 50 100 150 200 250 LED PIN VOLTAGE [mV] 300 Dimming Waveform © 2007 Catalyst Semiconductor, Inc. Characteristics subject to change without notice 7 Doc. No. 5023, Rev. B CAT3644 PIN DESCRIPTION Pin # Name Function 1 LED2 LED2 cathode terminal. 2 LED3 LED3 cathode terminal. 3 LED4 LED4 cathode terminal. 4 RSET Connect resistor RSET to set the LED current. 5 EN/DIM 6 VOUT 7 NC Not connected inside the package. 8 VIN Charge pump input, connect to battery or supply. 9 C1+ Bucket capacitor 1 Positive terminal 10 C1- Bucket capacitor 1 Negative terminal 11 C2+ Bucket capacitor 2 Positive terminal 12 C2- Bucket capacitor 2 Negative terminal 13 NC Not connected inside the package. 14 NC Not connected inside the package. 15 GND Ground Reference 16 LED1 LED1 cathode terminal. TAB GND Connect to GND on the PCB. Device enable (active high) and Dimming Control. Charge pump output connected to the LED anodes. 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 2.5V to 5.5V. Whenever the input supply falls below the under-voltage threshold (1.8V), all the LED channels are disabled and the device enters shutdown mode. C1+, C1- are connected to each side of the ceramic bucket capacitor C1. C2+, C2- are connected to each side of the ceramic bucket capacitor C2. LED1 to LED4 provide the internal regulated current source for each of the LED cathodes. These pins enter high-impedance zero current state whenever the device is placed in shutdown mode. EN/DIM is the enable and one wire dimming input for all LED channels. 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 are set to the full scale according to the resistor RSET. To place the device into “zero current” shutdown mode, the EN/DIM pin must be held low for at least 1.5ms. 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. RSET is connected to the resistor (RSET) to set the full scale current for the LEDs. The voltage at this pin regulated to 0.6V. The ground side of the external resistor should be star connected back to the GND of the PCB. In shutdown mode, RSET beomes high impedance. 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. Doc. No. 5023, Rev. B 8 © 2007 Catalyst Semiconductor, Inc. Characteristics subject to change without notice CAT3644 BLOCK DIAGRAM C1- VIN C1+ C2- C2+ VOUT 1x mode (LDO) 4/3x, 3/2x, 2x Charge Pump Mode Control 1, 1.3MHz Oscillator EN/DIM LED1 100kΩ LED2 Serial Interface Referece Voltage Registers Current Setting DAC LED3 LED4 LED Channel Current Regulators RSET GND Figure 2. CAT3644 Functional Block Diagram BASIC OPERATION At power-up, the CAT3644 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. This sequence repeats in the 1.33x and 1.5x mode until the driver enters the 2x mode. In 1.5x mode, the output voltage is approximately equal to 1.5 times the input supply voltage. While in 2x mode, the output is approximately equal to 2 times the input supply voltage. If the device detects a sufficient input voltage is present to drive all LED currents in 1x mode, it will change automatically back to 1x mode. This only applies for changing back to the 1x mode. The difference between the input voltage when exiting 1x mode and returning to 1x mode is called the 1x mode transition hysteresis (VHYS) and is about 500mV. If the input voltage is insufficient or falls to a level where the regulated currents cannot be maintained, the device automatically switches into 1.33x mode (after a fixed delay time of about 400μs). In 1.33x mode, the output voltage is approximately equal to 1.33 times the input supply voltage (less any internal voltage losses). © 2007 Catalyst Semiconductor, Inc. Characteristics subject to change without notice 9 Doc. No. 5023, Rev. B CAT3644 LED Current Selection At power-up, the initial LED current is set to full scale (100% brightness) by the external resistor RSET as follows: 0 .6 V LED current = 132 × R SET The EN/DIM pin has two primary functions. One function enables and disables the device. The other function is LED current dimming with six different TSETUP levels by pulsing the input signal, as shown on Figure 3. On each consecutive pulse rising edge, the LED current is divided by half to 50%, then 25%, 12.5%, 6.25% and 3.125% dimming levels. Pulses faster than the minimum TLO may be ignored and filtered by the device. Pulses longer than the maximum TLO may shutdown the device. The LED driver enters a “zero current” shutdown mode if EN/DIM is held low for 1.5ms or more. TPWRDWN THI EN/DIM TLED TLO 100% 100% 50% LED Current 25% Shutdown 12.5% 6.25% 3.12% Shutdown Figure 3. EN/DIM Digital Dimming Timing Diagram Table 1. LED Current Dimming Levels EN/DIM # of pulses * RSET Gain EN = High 132 132 × 0.6 V R SET st 66 66 × 0.6 V R SET nd 33 1 2 LED Current 33 × 0.6 V R SET rd 16.5 16.5 × 0.6 V R SET 4 th 8.25 8.25 × 0.6 V R SET 5 th 4.125 4.125 × 0.6 V R SET 6 th 132 th Device cycling through gain selection 3 x 132 × 0.6 V R SET GAIN × 0.6 V R SET * The gain is changed on the rising edges of the EN/DIM input. Doc. No. 5023, Rev. B 10 © 2007 Catalyst Semiconductor, Inc. Characteristics subject to change without notice CAT3644 Unused LED Channels External Components For applications not requiring all the channels, it is recommended the unused LED pins be tied directly to VOUT (see Figure 4). The driver requires four external 1μF ceramic capacitors for decoupling input, output, and for the charge pump. Both capacitors type X5R and X7R are recommended for the LED driver application. In all charge pump modes, the input current ripple is kept very low by design and an input bypass capacitor of 1μF is sufficient. 1µF C1+ VIN CIN C2VOUT COUT 1µF ENABLE DIMMING C1- C2+ VIN 1µF CAT3644 LED1 1µF In 1x mode, the device operates in linear mode and does not introduce switching noise back onto the supply. EN/DIM LED2 RSET LED3 Recommended Layout LED4 In charge pump mode, the driver switches internally at a high frequency. 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 TQFN exposed pad (TAB) must be connected to the ground plane underneath. The use of multiple via improves the package heat dissipation. GND RSET Figure 4. Application with 3 LEDs Protection Mode If an LED is disconnected, the driver senses that and automatically ignores that channel. When all LEDs are disconnected, the driver goes to 1x mode where the output is equal to the input voltage. GND As soon as the output exceeds about 6V, the driver resets itself and reevaluate the mode. If the die temperature exceeds +150°C, the driver will enter a thermal protection shutdown mode. When the device temperature drops by about 20°C, the device will resume normal operation. Pin1 C2 LED Selection LEDs with forward voltages (VF) ranging from 1.3V to 4.3V may be used. Selecting LEDs with lower VF is recommended in order to improve the efficiency by keeping the driver in 1x mode longer as the battery voltage decreases. EN/DIM VIN GND For example, if a white LED with a VF of 3.3V is selected over one with VF of 3.5V, the driver will stay in 1x mode for lower supply voltage of 0.2V. This helps improve the efficiency and extends battery life. © 2007 Catalyst Semiconductor, Inc. Characteristics subject to change without notice C1 RSET COUT CIN GND Figure 5. Recommended Layout 11 Doc. No. 5023, Rev. B CAT3644 PACKAGE OUTLINES 16 LEAD TQFN (HV3), 3mm x 3mm, 0.5mm PITCH 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 0.28 D 2.90 3.00 3.10 D2 1.40 1.55 1.70 E 2.90 3.00 3.10 E2 1.40 1.55 1.70 e L 0.50 TYP 0.35 0.40 0.45 For current Tape and Reel information, download the PDF file from: http://www.catsemi.com/documents/tapeandreel.pdf. Notes: (1) All dimensions are in millimeters, angles in degrees. (2) Complies with JEDEC Standard MO-220. Doc. No. 5023, Rev. B 12 © 2007 Catalyst Semiconductor, Inc. Characteristics subject to change without notice CAT3644 EXAMPLE OF ORDERING INFORMATION Prefix CAT Device # Suffix 3644 HV3 Product Number Optional Company ID Package – T2 Tape & Reel T: Tape & Reel 2: 2000/Reel HV3: TQFN Notes: (1) All packages are RoHS-compliant (Lead-free, Halogen-free). (2) The standard lead finish is Matte-Tin. (3) The device used in the above example is a CAT3644HV3–T2 (TQFN, Tape & Reel). (4) For additional package and temperature options, please contact your nearest Catalyst Semiconductor Sales office. © 2007 Catalyst Semiconductor, Inc. Characteristics subject to change without notice 13 Doc. No. 5023, Rev. B REVISION HISTORY Date Rev. Reason 01/29/2007 A Initial Release 02/26/2007 B Electrical Operating Characteristics – Add the pull-down resistor value 100kΩ Block Diagram – Add a 100kΩ pull-down resistor Copyrights, Trademarks and Patents Trademarks and registered trademarks of Catalyst Semiconductor include ech of the following: Beyond Memory™, DPP™, EZDim™, MiniPot™, and Quad-Mode™ 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: 5023 Revision: B Issue date: 02/26/07