CAT32_08 CATALYST | Alldatasheet
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© Catalyst Semiconductor, Inc. 1 Doc. No. MD-5001 Rev. AD Characteristics subject to change without notice CMOS White LED Driver
FEATURES
Low quiescent ground current (0.5mA typical) Power efficiency over 80% Compatible pinout with LT1932 Adjustable output current (up to 40mA) High frequency 1.2MHz operation Input voltage operation down to 2.0V Low resistance (0.5Ω) high voltage power switch Drives up to 4 White LEDs in series Shutdown current less than 1µA Load fault protection against open-circuits Low value external components Low profile (1mm) TSOT-23 6-lead and TDFN 8-pad (0.8mm) package APPLICATION Color LCD and keypad backlighting Cellular phones Handheld terminals Digital cameras PDAs/Games Portable MP3 players For Ordering Information details, see page 14.
DESCRIPTION
The CAT32 is a DC/DC step up converter that delivers a regulated output current. Operation at a constant switching frequency of 1.2MHz allows the device to be used with very small value external inductor and ceramic capacitors. The CAT32 is targeted to drive multiple white light- emitting diodes (LEDs) connected in series and provides the necessary regul ated current to control the brightness and the color purity. An external resistor R SET controls the output current level. LED currents of up to 40mA can be supported over a wide range of input supply voltages from 2V to 7V, making the device ideal for battery-powered applications. A high voltage output stage allows up to 4 White LEDs to be driven in series. Series drive provides inherent current matching. LED dimming can be done by using a DC voltage, a logic signal, or a pulse width modulation (PWM) signal. The shutdown input pin allows the device to be placed in power-down mode with “near zero” quiescent current. In addition to overcurrent limiting protection, the device also includes detection circuitry to ensure protection against open-circuit load fault conditions. The device is available in a low profile (1mm max height) 6-lead TSOT-23 package and in an 8-pad TDFN (0.8mm max height) package. TYPICAL APPLICATION CIRCUIT Figure 1. Li-Ion Driver for Four High-Brightness White LEDs
Doc. No. MD-5001 Rev. AD 2 © Catalyst Semiconductor, Inc. Characteristics subject to change without notice
ORDERING INFORMATION
Part Number Package Reel Quantity Package Marking Code CAT32TDI-T3 TSOT23-6 3000 LL CAT32ZD4-GT3 TDFN-8 3000 CCKV CAT32TDI-GT3 TSOT23-6 3000 VF PIN CONFIGURATION TSOT-23 6-Lead Top View 1mm maximum height θJA = 250ºC/W [free air] TDFN 3 x 3mm Power GROUND VIN SHDN RSET SW NC LED GND 0.8mm maximum height (Top View) PIN DESCRIPTION Pin Number SOT23 Pin Number TDFN Name Function 1 8 SW Switch pin. This is the drain of the internal power switch. For minimum EMI, minimize the trace area connected to this pin. 2 5 GND Ground pin. Connect pin 2 to ground. 3 6 LED LED (cathode) connection pin. 4 4 RSET RESET pin. A resistor connected from pin 4 to ground sets the LED current. This pin is also used to dim the LEDs. 5 3 SHDN¯¯¯¯¯ Shutdown pin. 6 2 VIN Input supply pin. This pin should be bypassed with a capacitor to ground. A 4.7µF capacitor mounted close to the pin is recommended. — 1 Power Ground Power Ground SHDN5 VIN LED RSET SW GND
© Catalyst Semiconductor, Inc. 3 Doc. No. MD-5001 Rev. AD Characteristics subject to change without notice ABSOLUTE MAXIMUM RATINGS (1) Parameter Rating Unit VIN, LED, SHDN¯¯¯¯¯ voltage 8 V SW voltage 20 V RSET voltage 1 V Storage Temperature Range -65 to +150 ºC Junction Temperature 125 ºC Lead Soldering Temperature (10 secs) 300 ºC ESD Rating – Human Body Model 2000 V RECOMMENDED OPERATING CONDITIONS Parameter Range Unit VIN 2 to 7 V Ambient Temperature Range -40 to +85 ºC Inductor L1 6.8 ±20% typical µH Input Capacitor C1 4.7 ±20% typical µF Output Capacitor C2 1.0 ±20% typical µF ILED with 1 to 4 LEDs in series 0 to 20 mA Typical application circuit with external components is shown on page 1. ELECTRICAL OPERATING CHARACTERISTICS Over recommended operating conditions unless otherwise specified. TA = 25ºC, VIN = 2V and VSHDN¯¯¯¯¯ = 1.2V. Symbol Parameter Conditions Min Typ Max Unit IQ Quiescent Current V RSET = 0.2V 0.5 0.7 mA IGND Ground Current in Shutdown VSHDN¯¯¯¯¯ = 0V 0.05 1 µA VLED LED Pin Voltage V IN < VOUT, ILED =15mA 120 180 mV ILED LED Current Adjust Range 5 40 mA RSET = 562Ω 33 38 45 RSET = 750Ω 25 30 36 RSET = 1.5kΩ 12.5 15 17.5 ILED Programmed LED Current RSET = 4.53kΩ 5 mA ILED LED Pin Current Temperature Coefficient I LED = 15mA -0.01 mA/°C VRSET RSET Pin Voltage R SET = 1.5kΩ 100 mV Shutdown Pin Logic High Level 0.85 V Shutdown Pin Logic Low Level 0.25 V fSW Boost Converter Frequency 0.8 1.2 1.6 MHz ISWL Switch Current Limit 400 550 780 mA VIN = 2V, ISW = 100mA 0.7 1.2 Ω RSW Switch Resistance VIN = 3V, ISW = 100mA 0.5 0.9 Ω Switch Leakage Curr ent Switch Off, V SW = 5V 0.01 5 µA Efficiency Components shown on Figure 1 83 % Notes: (1) These are stress ratings only and functi onal operation is not implied. Exposure to absolute maximum ratings for prolonged t ime periods may affect device reliability. All voltages are with respect to ground.
Doc. No. MD-5001 Rev. AD 4 © Catalyst Semiconductor, Inc. Characteristics subject to change without notice TYPICAL CHARACTERISTICS VIN = 3.6V, TAMB = 25ºC, CIN = 4.7µF, COUT = 1µF, L = 6.8µH, unless otherwise specified. Quiescent Current vs. Input Voltage 200 300 400 500 600 23 4 5 67 INPUT VOLTAGE [V] QUIESCENT CURRENT [µA] Quiescent Current vs. Temperature 200 300 400 500 600 - 5 0 - 2 50 2 55 07 5 1 0 0 1 2 5 VIN = 7V VIN = 2V TEMPERATURE [ºC] QUIESCENT CURRENT [µA] Switching Frequency vs. Input Voltage INPUT VOLTAGE [V] SWITCH FREQUENC Y [MHz] 0.00 0.40 0.80 1.20 1.60 2.00 234567 Switching Frequency vs. Temperature 0.0 0.4 0.8 1.2 1.6 2.0 -50 -25 0 25 50 75 100 125 TEMPERATURE [ºC] SWITCH FREQUENC Y [MHz] LED Current vs. Input Voltage 23 45 67 RSET =7 5 0Ω RSET = 1.13kΩ RSET = 1.50kΩ RSET = 2.26kΩ INPUT VOLTAGE [V] LED CURRENT [mA] LED Current vs. Temperature -50 -25 0 25 50 75 100 12 5 TEMPERATURE [ºC] LED CURRENT [mA]
© Catalyst Semiconductor, Inc. 5 Doc. No. MD-5001 Rev. AD Characteristics subject to change without notice TYPICAL CHARACTERISTICS VIN = 3.6V, TAMB = 25ºC , CIN = 4.7µF, COUT = 1µF, L = 6.8µH, unless otherwise specified. Switch Resistance vs. Input Voltage 0.0 0.2 0.4 0.6 0.8 1.0 23456 INPUT VOLTAGE [V] SWITCH RESISTANCE [Ω] Switch Resistance vs. Temperature 0.0 0.2 0.4 0.6 0.8 1.0 -50 -25 0 25 50 75 100 125 TEMPERATURE [ºC] VIN = 3V SWITCH RESISTANCE [Ω] LED Pin Voltage vs. LED current 100 150 200 250 300 0 8 16 24 32 40 LED PIN VOLTAGE [mV] LED CURRENT [mA] VSW, IL, & VOUT Signal Waveforms Efficiency vs. Input Voltage 23 4 5 6 INPUT VOLTAGE [V]
4 LEDs at 15m A
VOUT = 13V EFFICIENCY [%] PWM on SHDN¯¯¯¯¯ pin Waveform
Doc. No. MD-5001 Rev. AD 6 © Catalyst Semiconductor, Inc. frequency, current regulating boost converter. with a multiplication factor of 225. protecting the device, for the remainder of the cycle. Figure 2. CAT32 Block Diagram
© Catalyst Semiconductor, Inc. 7 Doc. No. MD-5001 Rev. AD Characteristics subject to change without notice
APPLICATION INFORMATION
INDUCTOR SELECTION AND EFFICIENCY Inductor vendors are shown below. Contact the manufac turer for detailed technical data and new product information. Table 1: Inductor Manufacturers Inductor L (μH) Maximum DCR (mΩ) Maximum Height (mm) Vendor Web ELJEA4R7 4.7 180 2.2 ELJEA6R8 6.8 250 2.2 Panasonic 714.373.7334 www.panasonic.com LQH3C4R7M24, LQH32CN4R7M11 4.7 260 2.2 LQH3C100K24, LQH32CN100K11 10 300 2.2 Murata 770.436.1300 www.murata.com LB2016B4R7 4.7 250 2.0 LB2016B100 3.8 350 2.0 Taiyo Yuden 408.573.4150 www.t-yuden.com CMD4D06-4R7 4.7 216 0.8 CMD4D06-6R8 6.8 296 0.8 CLQ4D10-4R7 4.7 162 1.2 CLQ4D10-6R8 6.8 195 1.2 Sumida 847.956.0666 www.sumida.com CAPACITOR SELECTION Low ESR (equivalent series resistance) capacitors should be used at the output to minimize the output ripple voltage. The low ESR and small package options available with multilayer ceramic capacitors make them excellent choices. The X5R and X7R capacitor types are preferred because they retain their capacitance over wider voltage and temperature ranges than the Y5V or Z5U types. A 1.0µF or 2.2µF output capacitor is recommended for most applications. The voltage rating of the output capacitor C2 depends on the number of LEDs driven in series. A 10V ceramic capacitor is recommended when driving two LEDs. A 16V ceramic capacitor is recommended when driving 3 or 4 LEDs. Table 2: Ceramic Capacitor Manufacturers Supplier Phone Web Taiyo Yuden 408.573.4150 www.t-yuden.com Murata 814.237.1431 www.murata.com Kemet 408.986.0424 www.kemet.com Low profile ceramic capacitors with a 1mm maximum height/thickness are available for designs height requirements. Ceramic capacitors also make a good choice for the input capacitor, which should be mounted as close as possible to the CAT32. A 2.2µF or 4.7µF input capacitor is recommended. Table 2 shows a list of several ceramic capacitor manufacturers. Consult the manufacturers for detailed information as new products and package options are introduced regularly.
Doc. No. MD-5001 Rev. AD 8 © Catalyst Semiconductor, Inc. Characteristics subject to change without notice DIODE SELECTION Schottky diodes, with their low forward voltage drop and fast switching speed, are the ideal choice for high efficiency applications. Table 3 shows several different Schottky diodes that work well with the CAT32. Make sure that the diode has a voltage rating greater than the output vo ltage. The diode conducts current only when the power switch is turned off (typically less than one-third the time), so a 0.4A or 0.5A diode will be sufficient for most designs. Table 3: Schottky Diode Suppliers Part Supplier MBR0520 MBR0530 s MBR0540 ON Semiconductor www.onsemi.com 800.282.9855 ZHCS400 Zetex LED CURRENT PROGRAMMING The LED current is programmed with a single resistor connected to the RSET pin The RSET pin is internally regulated to 100mV, which sets the current flowing out of this pin, ISET, equal to 100mV/RSET. The CAT32 regulates the current into the LED pin, ILED, to 225 times the value of I SET. For the best accuracy, a 1% or better resistor is recommended. Table 4 shows several typical 1% RSET values. Table 4: RSET Resistor Values ILED (mA) RSET 40 562 Ω 30 750 Ω 25 909 Ω 20 1.13k Ω 15 1.50k Ω 10 2.26k Ω 5 4.53k Ω For other LED current values, use the following equation to choose RSET. Most white LEDs are driven at maximum currents of 15mA to 20mA. Some higher power designs will use two parallel strings of LEDs for greater light output, resulting in 30mA to 40mA (two strings of 15mA to 20mA) flowing into the LED pin. LED DIMMING WITH PWM SIGNAL PWM brightness control provides the widest dimming range (greater than 20:1). By turning the LEDs ON and OFF using the control signal the LEDs operate at either zero or full current, but their average current changes with the PWM signal duty cycle. Typically, a 5kHz to 40kHz PWM signal is used. PWM dimming with the CAT32 can be accomplished two different ways. The SHDN ¯¯¯¯¯ pin can be driven directly or a resistor can be added to drive the RSET pin. If the SHDN¯¯¯¯¯ pin is used, increasing the duty cycle will increase the LED brightness. Using this method, the LEDs can be dimmed and turned off completely using the same control signal. A 0% duty cycle signal will turn off the CAT32, reducing the total quiescent current to near zero. If the RSET pin is used, increasing the duty cycle will decrease the brightness. Using this method, the LEDs are dimmed using RSET and turned off completely using SHDN ¯¯¯¯¯. If the RSET pin is used to provide PWM dimming, the approximate value of R PWM should be calculated (where VMAX is the “HIGH” value of the PWM signal): In addition to providing the widest dimming range, PWM brightness control also ensures the “purest” white LED color over the entire dimming range. The true color of a white LED changes with operating current, and is the “purest” white at a specific forward current, usually 15mA or 20mA. If the LED current is less than or more than this value, the emitted light becomes more blue. Applications involving color LCDs can find the blue tint objectionable. When a PWM control signal is used to drive the SHDN ¯¯¯¯¯ pin of the CAT32, the LEDs are turned off and on at the PWM frequency. The current through them alternates between full current and zero current, so the average current changes with duty cycle. This ensures that when the LEDs are on, they can be driven at the appropriate current to give the purest white light. LED brightness varies linearly with the PWM duty cycle. LED SET I V1.0×255=R )1–V15.0 V(×R=R MAX SETPWM
when the external NMOS switch is turned ON. plane under the switching regulator. shared with other components. Figure 3. LED Dimming Circuits
Doc. No. MD-5001 Rev. AD 10 © Catalyst Semiconductor, Inc. Characteristics subject to change without notice TYPICAL APPLICATION CIRCUITS The application diagrams below are shown for the TSOT-23 packages. Two LEDs with DC Level Dimming Control Three LEDs with DC Level Dimming Control Efficiency - Three LEDs Four LEDs with PWM Dimming Control 15mA4 RSET 1.50kΩ 6.8µH SWVIN SHDN RSET 1µF 4.7µF VIN PWM DIMMING CONTROL CAT32 LED GND Efficiency - Four LEDs EFFICIENCY [%] LED CURRENT [mA] 0 5 10 15 20 VIN = 4.2V VIN =3 . 0 V EFFICIENCY [%] LED CURRENT [mA] 0 5 10 15 20 VIN =4 . 2 V VIN =3 . 0 V 2.5V DC DIMMING CONTROL 15mA4 RSET 1.50kΩ 60.40kΩ 6.8µH SWVIN SHDN RSET 1µF 4.7µF VIN CAT32 LED GND 2.5V DC DIMMING CONTROL 15mA RSET 1.50kΩ 60.40kΩ 6.8µH SWVIN SHDN RSET 2.2µF 4.7µF VIN CAT32 LED GND
© Catalyst Semiconductor, Inc. 11 Doc. No. MD-5001 Rev. AD Characteristics subject to change without notice PACKAGE OUTLINE DRAWINGS TSOT-23 6-Lead (TD) (1)(2) Notes: (1) All dimensions are in millimeters. Angles in degrees. (2) Complies with JEDEC standard MO-193. For current Tape and Reel information, download the PDF file from: http://www.catsemi.com/documents/TapeandReel.pdf θ E1 E e b D c A TOP VIEW SIDE VIEW END VIEW L SYMBOL MIN NOM MAX A1 . 0 0 A1 0.01 0.05 0.10 A2 0.80 0.87 0.90 b0 . 3 0 0 . 4 5 c 0.12 0.15 0.20 D 2.90 BSC E 2.80 BSC E1 1.60 BSC e0 . 9 5 T Y P L 0.30 0.40 0.50 L1 0.60 REF L2 0.25 BSC θ 0º 8º
Doc. No. MD-5001 Rev. AD 12 © Catalyst Semiconductor, Inc. Characteristics subject to change without notice TDFN 8-Pad, 3 x 3mm (ZD4) (1)(2) Notes: (1) All dimensions are in millimeters. (2) Complies with JEDEC standard MO-229. For current Tape and Reel information, download the PDF file from: http://www.catsemi.com/documents/TapeandReel.pdf eb A SIDE VIEW BOTTOM VIEW E D TOP VIEW PIN#1 INDEX AREA PIN#1 ID FRONT VIEW A L SYMBOL MIN NOM MAX A 0.70 0.75 0.80 A1 0.00 0.02 0.05 A3 0.20 REF b 0.23 0.30 0.37 D 2.90 3.00 3.10 D2 2.20 — 2.50 E 2.90 3.00 3.10 E2 1.40 — 1.80 e0 . 6 5 T Y P L 0.20 0.30 0.40
© Catalyst Semiconductor, Inc. 13 Doc. No. MD-5001 Rev. AD Characteristics subject to change without notice EXAMPLE OF ORDERING INFORMATION1 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 CAT32Z D4-GT3 (TDFN, NiPdAu, Tape & Reel, 3,000/Reel). (4) For additional package and temperature options, please contact your nearest Catalyst Semiconductor Sales office. Prefix Device # Suffix CAT 32 ZD4 – G T3 Product Number Tape & Reel T: Tape & Reel 3: 3 ,000/Reel Lead Finish G: NiPdAu Package ZD4: TDFN TD: TSOT-23 Optional Company ID For Product Top Mark Codes, click here: http://www.catsemi.com/techsupport/producttopmark.asp
REVISION HISTORY
Date Rev. Reason 9-Oct-03 AA Revised Typica l Characteristics plots 11-Feb-04 AB Revised Efficiency plots 1-Nov-04 AC Added Green package designation Eliminated TDFN (3 x 4.9mm) package 23-May-08 AD Update Package Outline Drawings Delete PbSn plated finish; add NiPdAu plated finish Add Example of Ordering Information Add MD- to document number. Catalyst Semiconductor, Inc. Corporate Headquarters
2975 Stender Way
Santa Clara, CA 95054 Phone: 408.542.1000 Document No: MD-5001 Fax: 408.542.1200 Revision: AD www.catsemi.com Issue date: 05/23 /2008 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 Quant um 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.