AP1534 PWM CONTROL 2A STEP-DOWN CONVERTER General Description Features • • • • • • • • • AP1534 consists of step-down switching regulator with PWM control. These devices include a reference voltage source, oscillation circuit, error amplifier, internal PMOS. Input voltage: 4.4V to 18V Output voltage: 0.8V to VCC. Duty ratio: 0% to 99% PWM control Oscillation frequency: 300KHz typ. Current limit, Enable function Thermal Shutdown function Built-in internal SW P-channel MOS SOP-8L: Available in “Green” Molding Compound (no Br, Sb) Lead Free Finish/RoHS Compliant (Note 1) AP1534 provides low-ripple power, high efficiency, and excellent transient characteristics. The PWM control circuit is able to vary the duty ratio linearly from 0 up to 99%. This converter also contains an error amplifier circuit as well as a soft-start circuit that prevents overshoot at startup. An enable function, an over current protect function and a short circuit protect function are built inside, and when OCP or SCP happens, the operation frequency will be reduced from 300KHz to 50KHz. Also, an internal compensation block is built in to minimize external component count. With the addition of an internal P-channel Power MOS, a coil, capacitors, and a diode connected externally, these ICs can function as step-down switching regulators. They serve as ideal power supply units for portable devices when coupled with the SOP-8L mini-packages, providing such outstanding features as low current consumption. Since this converter can accommodate an input voltage up to 18V, it is also suitable for the operation via an AC adapter. Applications • • • • • • • • PC Motherboard LCD Monitor Graphic Card DVD-Video Player Telecom Equipment ADSL Modem Printer and other Peripheral Equipment Microprocessor Core Supply Ordering Information AP1534 X X X Note: Note: Package Lead Free S : SOP-8L G : Green Packing -U : Tube -13 : Tape & Reel 1. RoHS revision 13.2.2003. Glass and High Temperature Solder Exemptions Applied, see EU Directive Annex Notes 5 and 7. Device Package Code Packaging (Note 2) Quantity AP1534S S SOP-8L 100 Tube Part Number Suffix -U 13” Tape and Reel Part Number Suffix 2500/Tape & Reel -13 Quantity 2. Pad layout as shown on Diodes Inc. suggested pad layout document AP02001, which can be found on our website at http://www.diodes.com/datasheets/ap02001.pdf. AP1534 Rev. 2 1 of 8 www.diodes.com DECEMBER 2007 © Diodes Incorporated AP1534 PWM CONTROL 2A STEP-DOWN CONVERTER Pin Assignments FB 1 8 Vss EN 2 7 Vss OCSET 3 6 Output VCC 4 5 Output AP1534 SOP-8L Pin Descriptions Pin Name Pin No. FB 1 Feedback pin EN 2 Power-off pin H: Normal operation (Step-down operation) L: Step-down operation stopped (All circuits deactivated) OCSET 3 Add an external resistor to set max output current VCC 4 IC power supply pin Output 5, 6 Switch Pin. Connect external inductor/diode here. Minimize trace area at this pin to reduce EMI VSS 7, 8 GND Pin AP1534 Rev. 2 Description 2 of 8 www.diodes.com DECEMBER 2007 © Diodes Incorporated AP1534 PWM CONTROL 2A STEP-DOWN CONVERTER Block Diagram Output Oscillation Circuit Reference Voltage Source Vcc + PWM-Switched Control Circuit FB - Thermal Shutdown VEN EN 100uA Vss OCSET Absolute Maximum Ratings Symbol Parameter ESD HBM Human Body Model ESD Protection ESD MM Machine Model ESD Protection Rating Unit 4.5 150 KV V VCC VCC Pin Voltage VSS - 0.3 to VSS + 20 V VFB Feedback Pin Voltage VSS - 0.3 to VCC V VEN EN Pin Voltage VSS - 0.3 to VIN V VOUT Switch Pin Voltage VSS - 0.3 to VIN V PD Power Dissipation Internally limited mW TJ Operating Junction Temperature Range TST Storage Temperature Range -20 to +125 o C -40 to +150 o C Caution: The absolute maximum ratings are rated values exceeding which the product could suffer physical damage. These values must therefore not be exceeded under any conditions. Recommended Operating Conditions Symbol VIN IOUT TA AP1534 Rev. 2 Parameter Input Voltage Output Current Operating Ambient Temperature 3 of 8 www.diodes.com Min 4.4 0 -25 Max 18 2 85 Unit V A o C DECEMBER 2007 © Diodes Incorporated AP1534 PWM CONTROL 2A STEP-DOWN CONVERTER Electrical Characteristics Symbol Parameter VFB Feedback Voltage IFB Feedback Bias Current ISW Switch Current Current Consumption ISHDN During Power Off ∆VOUT Line Regulation / VIN ∆VOUT Load Regulation /VOUT fOSC Oscillation Frequency Frequency of Current Limit fOSC1 or Short Circuit Protect VIH EN Pin Input Voltage VIL EN Pin Input Leakage ISH Current ISL IOCSET OCSET Pin Bias Current RDS(ON) Internal MOSFET RDS(ON) ( VIN = 12V, TA = 25°C, unless otherwise specified ) Conditions Min 0.784 2.0 Typ. 0.8 0.1 - Max 0.816 0.5 - Unit V µA A VEN = 0V - 10 - µA VIN = 5V~18V - 1 2 % IOUT = 0.1 to 2A - 0.2 0.5 % Measure waveform at SW pin 240 300 400 KHz Measure waveform at SW pin - 50 - KHz 2.0 75 - 20 -10 90 160 100 0.8 105 - - 91 - % - 150 - °C - 55 - °C - 127 - o C/W - 28 - o C/W IOUT = 0.1A IOUT = 0.1A -- Evaluate oscillation at SW pin Evaluate oscillation stop at SW pin ---VIN = 5V, VFB = 0V VIN = 12V, VFB = 0V VIN = 12V, VOUT = 5V IOUT = 2A EFFI Efficiency TSHDN Thermal shutdown threshold Thermal shutdown hysteresis Thermal Resistance SOP-8L (Note 3) Junction-to-Ambient Thermal Resistance SOP-8L (Note 3) Junction-to-Case THYS θJA θJC Note: V µA µA µA mΩ 3. Test condition for SOP-8L: Device mounted on FR-4 substrate PC board, 2oz copper, with minimum recommended pad layout. For better thermal performance, larger copper pad for heatsink is needed. Typical Application Circuit 22uH L1 Vcc V IN R OCSET COCSET 5.6K Option CIN CC Optional AP1534 CVcc 0.1uF REN 100K EN RA 6.8K + FB OCSET 470uF V OUT =5V/2A Output VSS D1 B240A (Note 4) - + C 0.1uF - COUT 470uF RB 1.3K CEN 0.1uF Note: VOUT = VFB x (1+RA /RB ) RB =0.7K~5K ohm Note: 4. Suggested DIODES Power Schottky P/N: B240/B340 series. AP1534 Rev. 2 4 of 8 www.diodes.com DECEMBER 2007 © Diodes Incorporated AP1534 PWM CONTROL 2A STEP-DOWN CONVERTER Typical Performance Characteristics VIN vs VFB (VOUT=3.3V, IOUT=0.2A) 0.820 0.815 0.810 0.805 0.800 0.795 0.790 0.785 0.780 VFB (V) FOSC (kHz) 326 324 322 320 318 316 314 312 310 308 306 VIN vs Frequency (VOUT=3.3V, IOUT=0.2A) 0 2 4 8 10 VIN (V) 12 14 16 0 18 6 8 10 VIN (V) 12 Load Regulation (VIN=5V, VOUT=3.3V) 1.0% 0.0% -1.0% -2.0% -3.0% 2 4 Line Regulation 2.0% 0 2 (VOUT=3.3V, IOUT=0.2A) VOUT CHANGE (%) VOUT CHANGE (%) 3.0% 6 4 6 8 10 VIN (V) 12 14 16 18 1.0% 0.8% 0.6% 0.4% 0.2% 0.0% -0.2% -0.4% -0.6% -0.8% -1.0% 0.0 0.5 1.0 IOUT (A) 14 1.5 16 18 2.0 Efficiency Efficiency (%) 100 90 80 70 60 50 40 30 20 10 0 VOUT=3.3V VOUT=5V 0.0 AP1534 Rev. 2 0.5 1.0 IOUT (A) 1.5 2.0 5 of 8 www.diodes.com DECEMBER 2007 © Diodes Incorporated AP1534 PWM CONTROL 2A STEP-DOWN CONVERTER Typical Performance Characteristics (Continued) Vout Ripple (Vin=5V, Vout=3.3V, Iout=0.1A) Vout Ripple (Vin=5V, Vout=3.3V, Iout=2A) Test Circuit VCC OUTPUT FB Oscillation open open OCSET A EN + - VSS Enable function test VCC + - A OUTPUT VCC OUTPUT OCSET EN FB VSS Feedback function test FB OCSET EN VSS + V - Operation function test AP1534 Rev. 2 6 of 8 www.diodes.com DECEMBER 2007 © Diodes Incorporated AP1534 PWM CONTROL 2A STEP-DOWN CONVERTER Function Description PWM Control The AP1534 is a DC/DC converter that employs pulse width modulation (PWM) scheme. Its pulse width varies in the range of 0% to 99%, based on the output current loading. The output ripple voltage caused by the PWM high frequency switching can easily be reduced through an output filter. Therefore, this converter provides a low ripple output supply over a broad range of input voltage & output current loading The current limit threshold is given by the following equation: IPEAK × RDS(ON) = IOCSET × R OCSET ( ΔI) IPEAK > IOUT (MAX) + 2 where, Under Voltage Lockout The under voltage lockout circuit of the AP1534 assures that the high-side MOSFET driver remains in the off state whenever the supply voltage drops below 3.3V. Normal operation resumes once VCC rises above 3.5V. ΔI = VIN − VOUT FSxL x VOUT VIN IPEAK is the output peak current; RDS (ON) is the MOSFET ON resistance; FS is the PWM frequency (300KHz typical). Also, the inductor value will affect the ripple current ΔI. Current Limit Protection The current limit threshold is set by external resistor ROCSET connected from VCC supply to OCSET pin. The internal sink current IOCSET (90uA typical) across this resistor sets the voltage at OCSET pin. When the PWM voltage is less than the voltage at OCSET, an over-current condition is triggered. The above equation is recommended for input voltage range of 5V to 18V. For input voltage lower than 5V, higher than 18V or ambient temperature over 100°C, ROCSET≧6.8KΩ is recommended. The recommended minimum ROCSET value is summarized below: VIN (V) VOUT (V) ROCSET (Ω) 4 1 6.8K 5 3.3 5.6K 12 5 3.9K 18 12 4.7K The maximum ROCSET value should not exceed AP1533 maximum current output. Marking Information ( Top View ) 8 5 Logo Part No. AP1534 YYWW X X 1 4 G : Green Internal code Xth week: 01~52 Year : "07" = 2007 "08" = 2008 ~ SOP-8L AP1534 Rev. 2 7 of 8 www.diodes.com DECEMBER 2007 © Diodes Incorporated AP1534 PWM CONTROL 2A STEP-DOWN CONVERTER Package Information 0.254 0.08/0.25 5.79/6.20 3.70/4.10 (All Dimensions in mm) Gauge Plane Seating Plane 0.38/1.27 Detail "A" 1.27typ 0.3/0.5 0.20typ 0.35max.45° 1.75max. 1.30/1.50 7°~9° 7°~9° Detail "A" 0.78 3.70/4.10 4.80/5.30 5.4 8x-0.60 8x-1.55 6x-1.27 Land Pattern Recommendation (Unit: mm) IMPORTANT NOTICE Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other changes without further notice to any product herein. Diodes Incorporated does not assume any liability arising out of the application or use of any product described herein; neither does it convey any license under its patent rights, nor the rights of others. The user of products in such applications shall assume all risks of such use and will agree to hold Diodes Incorporated and all the companies whose products are represented on our website, harmless against all damages. LIFE SUPPORT Diodes Incorporated products are not authorized for use as critical components in life support devices or systems without the expressed written approval of the President of Diodes Incorporated. AP1534 Rev. 2 8 of 8 www.diodes.com DECEMBER 2007 © Diodes Incorporated