AP1520 PWM CONTROL 2A STEP-DOWN CONVERTER General Description Features • • • • • • • • • AP1520 consists of step-down switching regulator with PWM control. These devices include a reference voltage source, oscillation circuit, error amplifier, and internal PMOS. Input Voltage: 3.6V to 23V Output Voltage: 0.8V to VCC Duty Ratio: 0% to 100% PWM Control Oscillation Frequency: 300KHz typ. Soft-Start, Current Limit, Enable Function Thermal Shutdown Function Built-in Internal SW P-Channel MOS SOP-8L Pb-Free Package Lead Free Finish/RoHS Compliant (Note 1) AP1520 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 100%. This converter also contains an error amplifier circuit as well as a soft-start circuit that prevents overshooting 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 30KHz. Also, an internal compensation block is built in to minimum 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-package, providing such outstanding features as low current consumption. Since this converter can accommodate an input voltage up to 23V, 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 Networking Power Supply Ordering Information AP 1520 X X X Lead-Free L : Lead- Free Package S : SOP-8L Note: Packing -U : Tube -13 : Taping 1. RoHS revision 13.2.2003. Glass and High Temperature Solder Exemptions Applied, see EU Directive Annex Notes 5 and 7. Device (Note 2) Lead-free AP1520S Package Packaging Code S SOP-8L Quantity 100/Tube Tube Part Number Suffix -U 13” Tape and Reel Quantity Part Number Suffix 2500/Tape & Reel Note: 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. AP1520 Rev. 1 1 of 8 www.diodes.com JANUARY 2007 © Diodes Incorporated -13 AP1520 PWM CONTROL 2A STEP-DOWN CONVERTER Pin Descriptions Pin Assignments Pin Pin Description Name No. FB 1 Feedback pin Power-off pin H: Normal operation EN 2 (Step-down operation) L: Step-down operation stopped (All circuits deactivated) Add an external resistor to set max OCSET 3 output current 4 IC power supply pin VCC Switch Pin. Connect external Output 5, 6 inductor/diode here. Minimize trace area at this pin to reduce EMI 7, 8 GND Pin VSS ( Top View ) FB 1 8 Vss EN 2 7 Vss OCSET 3 6 Output VCC 4 5 Output AP1520 SOP-8L Block Diagram Output Oscillation Circuit Reference Voltage Source with Soft Start Vcc + PWM-Switched Control Circuit FB - Thermal Shutdown VEN EN AP1520 Rev. 1 2 of 8 www.diodes.com 100uA Vss OCSET JANUARY 2007 © Diodes Incorporated AP1520 PWM CONTROL 2A STEP-DOWN CONVERTER Absolute Maximum Ratings Symbol VCC VFB VEN VOUT PD TOPR TSTG Parameter VCC Pin Voltage Feedback Pin Voltage EN Pin Voltage Switch Pin Voltage Power Dissipation Operating Temperature Range Storage Temperature Range Rating VSS - 0.3 to VSS + 25 VSS - 0.3 to VCC VSS - 0.3 to VIN + 0.3 VSS - 0.3 to VIN + 0.3 Internally limited -20 to +85 -40 to +150 Unit V V V V mW o C 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. Electrical Characteristics Symbol VIN VFB IFB ISW ISSS Parameter Input Voltage Feedback Voltage Feedback Bias Current Switch Current Current Consumption During Power off ∆VOUT Line Regulation /VOUT ∆VOUT Load Regulation /VOUT fOSC Oscillation Frequency Frequency of Current Limit fOSC1 or Short Circuit Protect VSH EN Pin Input Voltage VSL ISH EN Pin Input Leakage Current ISL IOCSET OCSET Pin Bias Current TSS Soft-Start Time RDSON Internal MOSFET RDSON EFFI θJA Efficiency ( VIN = 12V, Ta = 25°C, unless otherwise specified ) Conditions -IOUT = 0.1A IOUT = 0.1A -- Min. 3.6 0.784 2.5 Typ. 0.8 0.1 - Max. 23 0.816 0.5 - Unit V V µA A VEN = 0V - 10 - µA VIN = 5V~23V - 1 2 % IOUT = 0.1 to 2A - 0.2 0.5 % Measure waveform at SW pin 240 300 360 KHz Measure waveform at SW pin 10 - - KHz 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 2.0 75 0.3 - 20 -10 90 1 110 70 0.8 105 2 150 100 - 92 - - 65 - Thermal Resistance Junction-to-Ambient AP1520 Rev. 1 3 of 8 www.diodes.com V µA µA µA ms mΩ % o C/W JANUARY 2007 © Diodes Incorporated AP1520 PWM CONTROL 2A STEP-DOWN CONVERTER Typical Application Circuit VIN ROCSET COCSET 3K Option CIN AP1520 CVcc 0.1uF RA 6.8K + FB + C - 0.1uF- VSS EN REN 100K VOUT 22uH CC Optional OCSET 680uF L1 Output Vcc COUT 470uF RB 1.3K D1* CEN 0.1uF Note: VOUT = VFB x (1+RA/RB) RB=0.7K~5K ohm VIN = 12V, IMAX = 2A 2.5V 3.3V 22uH 27uH VOUT L1 Value 5V 33uH *D1 = Diodes Inc. part number DFLS230L or SBR3U30P1. Typical Performance Characteristics AP1520 Vin vs. Frequency (Vout=3.3V; Iout=0.2A) 350 345 335 FB (V) Fosc (KHz) 340 330 325 320 315 310 3.6 AP1520 Rev. 1 4 6 8 10 Vin (V) 12 14 16 18 4 of 8 www.diodes.com AP1520 Vin vs. FB (Vout=3.3V; Iout=0.2A) 0.84 0.83 0.82 0.81 0.80 0.79 0.78 0.77 0.76 0.75 0.74 3.6 4 6 8 10 Vin (V) 12 14 16 18 JANUARY 2007 © Diodes Incorporated AP1520 PWM CONTROL 2A STEP-DOWN CONVERTER Typical Performance Characteristics ( Continued ) AP1520 Line Regulation (Vin=12V; Iout=0.2A) 3.40 3.30 Vout (A) Vout (V) 3.35 3.25 3.20 3.15 3.10 3.6 4 6 8 10 Vin (V) 12 14 16 18 AP1520 Load Regulation (Vin=12V) 5.10 5.09 5.08 5.07 5.06 5.05 5.04 5.03 5.02 5.01 5.00 0.0 1.0 2.0 3.0 4.0 Iout (A) Efficiency (%) AP1520 Efficiency 100 90 80 70 60 50 40 30 20 10 0 Vout:5.0V Vout:3.3V 0.0 0.5 1.0 1.5 2.0 Iout (A) AP1520 Vout Ripple ( Vin = 12V; Vout = 3.3V; Iout = 0.1A ) AP1520 Rev. 1 5 of 8 www.diodes.com AP1520 Vout Ripple ( Vin = 12V; Vout = 3.3V; Iout = 2A ) JANUARY 2007 © Diodes Incorporated AP1520 PWM CONTROL 2A STEP-DOWN CONVERTER Test Circuit VCC OUTPUT FB Oscillation open open OCSET A EN VCC + - A + - VSS OUTPUT VCC OUTPUT OCSET EN FB VSS FB OCSET EN VSS + V - Function Description PWM Control The AP1520 consists of DC/DC converters that employ a Pulse-Width Modulation (PWM) system. In converters of the AP1520, the pulse width varies in a range from 0 to 100%, according to the load current. The ripple voltage produced by the switching can easily be removed through a filter because the switching frequency remains constant. Therefore, these converters provide a low-ripple power over broad ranges of input voltage and load current. resumes once VCC rises above 3.5V. RDS(ON) Current Limiting The current limit threshold is setting by the external resistor connecting from VCC supply to OCSET. The internal 100uA sink current crossing the resistor sets the voltage at the pin of OCSET. When the PWM voltage is less than the voltage at OCSET, an over-current condition is triggered. ILOAD × RDS(ON) = IOCSET × ROCSET Under Voltage Lockout The Under Voltage Lockout circuit of the AP1520 assures that the high-side MOSFET driver outputs remain in the off state whenever the supply voltage drops below 3.3V. Normal operation AP1520 Rev. 1 See above formula for setting the current limit value. 6 of 8 www.diodes.com JANUARY 2007 © Diodes Incorporated AP1520 PWM CONTROL 2A STEP-DOWN CONVERTER Marking Information (1) SOP-8L ( Top View ) 8 5 Logo Part no. AP1520 YY WW X 4 ~ 1 ID code: internal Xth week: 01~52 Year: "01" =2001 "02" =2002 Device Package Identification Code AP1520S SOP-8L AP1520 Package Information ( All Dimensions in mm ) 0.254 0.08/0.25 5.79/6.20 3.70/4.10 Package Type: SOP-8L Gauge Plane Seating Plane 0.38/1.27 Detail "A" 7°~9° 0.20typ 1.75max. 1.30/1.50 0.35max. 45° 0.3/0.5 1.27typ 7°~9° Detail "A" 3.70/4.10 4.80/5.30 AP1520 Rev. 1 7 of 8 www.diodes.com JANUARY 2007 © Diodes Incorporated AP1520 PWM CONTROL 2A STEP-DOWN CONVERTER 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. AP1520 Rev. 1 8 of 8 www.diodes.com JANUARY 2007 © Diodes Incorporated