AP5004 PWM CONTROL 2.5A STEP-DOWN CONVERTER General Description Features • • • • • • • • • • • Input Voltage: 10V to 32V Adjustable Output Voltage from 0.8V to 6V Duty Ratio: 0% to 90% PWM control Oscillation Frequency: 300KHz typical Short Circuit Protect Frequency:50 KHz 2uA Maximum Standby Current Current Limit, Enable Function Thermal Shutdown Function Built-in Internal SW N-channel MOS SOP-8L: Available in “Green” Molding Compound (No Br, Sb) Lead Free Finish/RoHS Compliant (Note 1) AP5004 consists of step-down switching regulator with PWM control. These devices include a reference voltage source, oscillation circuit, error amplifier, internal NMOS. AP5004 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 90%. 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 300 KHz to 50 KHz. Also, an internal compensation block is built to minimize external component count. With built-in power NMOS, a step-down switching regulator is easy to be built by adding a coil, capacitors and a diode. The high efficiency, low standby current, high input voltage (32V) and output current (2.5A) combining with small SOP-8L package give AP5004 unprecedented advantage in high power system applications. Applications • • • • Microprocessor Core Supply Networking Power Supply LCD MNT, TV Power Supply Telecom Power Supply Ordering Information AP5004 S G - X Device AP5004SG-U AP5004SG-13 Notes: Package Lead Free S : SOP-8L G : Green Package Packaging Code (Note 2) S S SOP-8L SOP-8L Packing U : Tube 13 : Tape & Reel Tube Part Number Quantity Suffix 100 -U NA NA 13” Tape and Reel Part Number Quantity Suffix NA NA 2500/Tape & Reel -13 1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied, see EU Directive 2002/95/EC Annex Notes. 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. AP5004 Rev. 3 1 of 10 www.diodes.com JUNE 2008 © Diodes Incorporated AP5004 PWM CONTROL 2.5A STEP-DOWN CONVERTER Pin Descriptions Pin Assignments (Top View ) EN FB 1 2 Vboost Output 3 AP5004 4 Pin Name 8 7 GND GND EN 6 Vcc 5 Vcc FB Vboost Output VCC GND SOP-8L Pin # Description H: Normal operation L: Step-down operation stopped 2 Feedback pin 3 High-side gate driver boost pin 4 Switch output pin 5、6 Signal VCC 7、8 GND pin 1 Block Diagram Output Vcc Oscillation Circuit Driver Reference Voltage + PWM - Switched Control Circuit - FB VL Thermal Shutdown EN Vboost AP5004 Rev. 3 VEN 2 of 10 www.diodes.com GND JUNE 2008 © Diodes Incorporated AP5004 PWM CONTROL 2.5A STEP-DOWN CONVERTER Absolute Maximum Ratings Symbol ESD HBM ESD MM VCC VFB VEN Vboost VOUTPUT TJ TST Parameter Human Body Model ESD Protection Machine Model ESD Protection VCC Pin Voltage VOUT Pin Voltage EN Pin Voltage Vboost Pin Voltage Switch Pin Voltage Operating Junction Temperature Range Storage Temperature Range Rating 1.8 550 VSS - 0.3 to VSS + 35 VSS - 0.3 to VCC VSS - 0.3 to VCC + 0.3 VOUTPUT + 7V VSS - 0.3 to VCC + 0.3 -10 to +125 -40 to +150 Unit KV V V V V V V 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. Recommended Operating Conditions Symbol VIN IOUT TA AP5004 Rev. 3 Parameter Input Voltage Output Current Operating Ambient Temperature 3 of 10 www.diodes.com Min 10 0 -10 Max 32 2.5 85 Unit V A o C JUNE 2008 © Diodes Incorporated AP5004 PWM CONTROL 2.5A STEP-DOWN CONVERTER Electrical Characteristics Symbol VFB VIN ISTBY ∆VOUT/VOUT ∆VOUT/VOUT fOSC fOSC1 DC VIH VIL ISH ISL Parameter Feedback Voltage Input Voltage Standby Current Line Regulation Load Regulation Oscillation Frequency Frequency of Current Limit or Short Circuit Protect Maximum Duty Cycle Minimum Duty Cycle EN Pin Logic Input Threshold Voltage Conditions VEN =0V VIN = 10V~32V IOUT = 0.1 to 2.5A Measure waveform at SW pin Min 0.780 10 240 Typ. 0.8 2 ±1.0 1 300 Max 0.820 32 ±1.5 1.5 360 Unit V V µA %/V % KHz Measure waveform at SW pin - 50 - KHz 2.0 3.5 - 90 0 20 -10 80 90 0.8 120 - % % SOP-8L (Note 3) - 124 - o SOP-8L (Note 3) - 25 - o VFB =0.5V VFB =1.0V Regulator ON Regulator OFF EN Pin Input Leakage Current RDS(ON) ILIMIT η θJA θJC Notes: (VIN = 12V, TA=25°C, unless otherwise specified) Internal MOSFET RDS(ON) Current Limit Efficiency Thermal Resistance Junction-to-Ambient Thermal Resistance Junction-to-Case VIN = 12V, VOUT = 5V, IOUT = 2.5A V µA µA mΩ A % C/W C/W 3. Test condition for SOP-8L: Device mounted on 2oz copper, minimum recommended pad layout, FR-4 PCB. Typical Application Circuit C7 0.1uF U1 3 VIN 5 6 R5 100K 1 Vboost Output VCC FB AP5004 VCC GND EN GND 4 1 2 7 8 R1 685ohm D1 B340 R2 130ohm C2 220uF/63V VOUT = 5V L1-(WURTH 744132) 33uH 2 C1 100pF C4 C5 470uF/16V 0.1uF C3 0.1uF C6 0.1uF Note: V OUT = VFB x (1+R1/R2) R B = 100 ~ 300 ohm Notes: 4. Suggested DIODES Power Schottky P/N: PDS540 or B540C. AP5004 Rev. 3 4 of 10 www.diodes.com JUNE 2008 © Diodes Incorporated AP5004 PWM CONTROL 2.5A STEP-DOWN CONVERTER Typical Performance Characteristics Load Regulation 1.2 1.5 1 1.2 Line Regulation(%) Load Regulation(%) Line Regulation 0.8 0.6 0.4 0.9 0.6 0.3 0.2 0 0 0 0 1 2 4 8 12 3 Iout(A) Frequency vs. Vin 16 Vin(V) 20 24 28 32 Iccq vs. Vin 330 7.45 Vout=5V;Iout=0.2A VFB=1V 7.4 Quiescent Current(mA) Frequency(KHz) 325 320 315 7.35 7.3 7.25 7.2 7.15 7.1 7.05 310 0 5 10 15 20 25 30 35 0 5 10 15 20 25 30 35 Vin(V) Vin(V) Istandby vs. Vin 0.15 VEN=0V Standby Current(uA) 0.12 0.09 0.06 0.03 0 0 5 10 15 20 25 30 35 Vin(V) AP5004 Rev. 3 5 of 10 www.diodes.com JUNE 2008 © Diodes Incorporated AP5004 PWM CONTROL 2.5A STEP-DOWN CONVERTER Typical Performance Characteristics (Continued) Vout Ripple Vout Ripple (Vcc= 12V, Vout= 5V, Iout= 0A, Vripple= 19.0mV) (Vcc= 12V, Vout= 5V, Iout= 2.5A, Vripple= 35.0mV) Power Transient Wave (Iout= 0.1~2.5A, Vin= 12V, Vout= 5V) Power Transient Wave (Iout= 0.1~2.5A, Vin= 32V, Vout= 5V) AP5004 Rev. 3 6 of 10 www.diodes.com JUNE 2008 © Diodes Incorporated AP5004 PWM CONTROL 2.5A STEP-DOWN CONVERTER Test Circuit OUTPUT Vcc A EN FB Vboost Oscillation open open A OUTPUT Vcc Vboost FB + open - GND Enable function test EN GND Feedback function test 33uH 0.1uF Vboost OUTPUT FB Vcc 530 ohm + - 220uF EN + GND 470uF - V 100 ohm Operation function test AP5004 Rev. 3 7 of 10 www.diodes.com JUNE 2008 © Diodes Incorporated AP5004 PWM CONTROL 2.5A STEP-DOWN CONVERTER Functional Description PWM Control The AP5004 consists of DC/DC converters that employ a pulse-width modulation (PWM) system. The PWM controller is internally clocked by a fixed 300KHz oscillator. In converters of the AP5004, the pulse width varies in a range from 0 to 90%, 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. Output Capacitor Selection The output capacitor is required to maintain the DC output voltage. Low ESR capacitors are preferred to keep the output voltage ripple low. The characteristics of the output capacitor also affect the stability of the regulation control system. The ESR dominates the impedance at the switching frequency, and so the output ripple is calculated as: Enable Control This allows the output of AP5004 to be turned ON or OFF. Connecting this pin to GND or any voltage lower than 0.8V turn off the output OFF. At OFF state current drawn through the VCC input is approximately 2uA. Note that the slew rate from ON to OFF must be >0.013v/us to ensure proper operation. Output Rectifier Diode The output rectifier diode supplies the current to the inductor when the high-side switch is off. To reduce losses due to the diode forward voltage and recovery times, use a Schottky rectifier. C BOOST A capacitor must be connected from pin 3 to the switch output, pin 4. This capacitor boosts the gate drive to the internal MOSFET above VIN to fully turn it ON. This minimizes conduction losses in the power switch to maintain high efficiency. The recommended value for C Boost is 0.1uF. FEEDBACK This is the input to a two-stage high gain amplifier, which drivers the PWM controller. It is necessary to connect pin 2 to the actual output of the power supply to set the DC output voltage. Two external resistors are required to set the DC output voltage. For stable operation of the power supply, it is important to prevent coupling of any inductor flux to the feedback input. V RIPPLE ≅ ΔI × RESR PCB Layout Guide If you need low TC & TJ or large PD(Power Dissipation), The dual Output pin(4) and VSS pins(7& 8)on the SOP-8L package are internally connected to die pad, The PCB layout should allow for maximum possible copper area at the SW pins. 1. Connect C3 to VCC and VSS pin as closely as possible to get good power filter effect. 2. Connect ground side of the C2 & D1 as closely as possible. Typical PC Board Layout Top Side Layout Guide Current Limit The current limit threshold is set by the internal circuit that minimum switching current is 3.5A. The output voltage will be reduced immediately and switching frequency will be dropped to 50KHz when switching current over limit threshold. Inductor Selection For most designs, the operates with inductors of 15µH to 33µH. The inductor value can be derived from the following equation: L= (VIN − VOUT )TON ΔI L × f osc Bottom Side Layout Guide Where is inductor Ripple Current. Large value inductors lower ripple current and small value inductors result in high ripple currents. Choose inductor ripple current approximately 15% of the maximum load current 2.5A, ∆IL=0.375A. The DC current rating of the inductor should be at least equal to the maximum load current plus half the ripple current to prevent core saturation (2A+0.19A). Input Capacitor Selection The input current to the step-down converter is discontinuous, and therefore an input capacitor C2 is required to supply the AC current to the step-down converter while maintaining the DC input voltage. A low ESR capacitor is required to keep the noise at the IC to a minimum. Its RMS current rating should be greater than approximately 1/2 of the DC load current. AP5004 Rev. 3 8 of 10 www.diodes.com JUNE 2008 © Diodes Incorporated AP5004 PWM CONTROL 2.5A STEP-DOWN CONVERTER Marking Information ( Top View ) 5 8 Logo A~Z : Green AP5004 YY WW X X Part No. 1 Internal code Xth week : 01~52 Year : "07" = 2007 "08" = 2008 4 ~ SOP-8L 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" 7°~9° 7°~9° 0.20typ 1.30/1.50 0.3/0.5 1.27typ 1.75max. 0.35max. 45° 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) AP5004 Rev. 3 9 of 10 www.diodes.com JUNE 2008 © Diodes Incorporated AP5004 PWM CONTROL 2.5A 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. AP5004 Rev. 3 10 of 10 www.diodes.com JUNE 2008 © Diodes Incorporated