AP5002 PWM CONTROL 2A STEP-DOWN CONVERTER General Description Features • • • • • • • • • • • Input voltage: 3.6V to 20V Output voltage: 0.8V to VCC Duty ratio: up to 100% PWM control Oscillation frequency: 500KHz typical Soft-start Current Limit, Enable function Thermal Shutdown function Built-in internal SW P-channel MOS Low ESR output capacitor (MLCC, multi-layer ceramic capacitor) support Efficiency 90% SOP-8L: Available in “Green” Molding Compound (No Br, Sb) Lead Free Finish / RoHS Compliant (Note 1) AP5002 consists of step-down switching regulator with PWM control. These devices include a reference voltage source, oscillation circuit, error amplifier, internal PMOS. AP5002 provides low-ripple power, high efficiency, and excellent transient characteristics. The PWM control circuit is able to vary the duty ratio linearly up to 100%. 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 500KHz to 50KHz. 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 22V, 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 AP5002 S G - 13 Package S : SOP-8L Device AP5002SG-13 Notes: Package Code S Green G : Green Packaging (Note 2) SOP-8L Packing 13 : Tape & Reel 13” Tape and Reel Quantity Part Number Suffix 2500/Tape & Reel -13 1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied. Please visit our website at http://www.diodes.com/products/lead_free.html. 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. AP5002 Rev. 8 1 of 10 www.diodes.com FEBRUARY 2009 © Diodes Incorporated AP5002 PWM CONTROL 2A STEP-DOWN CONVERTER Pin Assignments Pin Descriptions ( Top View ) FB 1 8 Vss EN 2 7 Vss Comp 3 6 Output VCC 4 5 Output Name Pin FB 1 EN AP5002 Comp VCC Output SOP-8L VSS Description Feedback pin Power-off pin H: Normal operation 2 (Step-down operation) L: Step-down operation stopped (All circuits deactivated) 3 Compensation pin 4 IC power supply pin Switch Pin. Connect external 5、6 inductor/diode here. Minimize trace area at this pin to reduce EMI. 7、8 GND Pin Block Diagram Output Oscillation Circuit Reference Voltage Source Vcc + PWM-Switched Control Circuit FB - Thermal Shutdown 100uA VEN EN AP5002 Rev. 8 2 of 10 www.diodes.com Vss Comp FEBRUARY 2009 © Diodes Incorporated AP5002 PWM CONTROL 2A STEP-DOWN CONVERTER Absolute Maximum Ratings Symbol Parameter ESD HBM Human Body Model ESD Protection ESD MM VCC VFB VEN VOUTPUT PD TJ TST Machine Model ESD Protection VCC Pin Voltage Feedback Pin Voltage EN Pin Voltage Switch Pin Voltage Power Dissipation Operating Junction Temperature Range Storage Temperature Range Rating Unit 5 200 VSS - 0.3 to VSS + 22 VSS - 0.3 to VCC VSS - 0.3 to VIN VSS - 0.3 to VIN 1000 -20 to +125 -65 to +150 KV V 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. Recommended Operating Conditions Symbol VIN IOUT TA AP5002 Rev. 8 Parameter Input Voltage Output Current Operating Ambient Temperature 3 of 10 www.diodes.com Min 3.6 0 -20 Max 20 2 85 Unit V A o C FEBRUARY 2009 © Diodes Incorporated AP5002 PWM CONTROL 2A STEP-DOWN CONVERTER Electrical Characteristics Symbol VFB IFB ICCQ ISW ISD ∆VOUT /VOUT ∆VOUT /VOUT fOSC VSH VSL ISH ISL TSS RDSON θJA θJC Notes: (VIN = 12V, TA = 25°C, unless otherwise specified) Parameter Feedback Voltage Feedback Bias Current Quiescent Current Switch Current Shutdown Supply Current Conditions IOUT = 0.1A IOUT = 0.1A VFB = 1.2 force drive off -VEN = 0V Min 0.784 3.5 - Typ. 0.8 0.1 3 10 Max 0.816 0.5 5 - Unit V µA mA A µA Line Regulation VIN = 4V~20V, IOUT = 0.2A - 1 2 % Load Regulation IOUT = 0.1 to 2A - 0.5 1 % Oscillation Frequency Measure waveform at SW pin Evaluate oscillation at SW pin Evaluate oscillation stop at SW pin Ven = 2V Ven = 0.8V -VIN = 5V, VFB = 0V VIN = 12V, VFB = 0V 400 2.0 -10 -10 - 500 3 110 70 600 0.8 10 10 150 100 KHz EN Pin Input Voltage EN Pin Input Leakage Current Soft-Start Time Internal MOSFET Rdson V µA µA ms mΩ Thermal shutdown 140 o Minimum Duty Cycle 6.5 % Thermal Resistance Junction-to-Ambient Thermal Resistance Junction-to-Case C SOP-8L (Note 3) 124 o C/W SOP-8L (Note 3) 25 o C/W 3. Test condition: Device mounted on 2oz copper, minimum recommended pad layout, FR-4 PCB. AP5002 Rev. 8 4 of 10 www.diodes.com FEBRUARY 2009 © Diodes Incorporated AP5002 PWM CONTROL 2A STEP-DOWN CONVERTER Typical Application Circuit U1 VIN+12V 1 C2 22uF C3 ON/OFF R5 100K 2 3 0.1uF C6 0.1uF 4 FB VSS EN VSS COMP Output VCC Output 8 7 L1-(WURTH S05100104) 10uH 2 1 6 D1 Dii 723 B340A 5 R1 3.8K VOUT = 3.3V C1 330pF C8 0.1uF AP5002 R4 0.8~2K C4 22uF R2 1.2K C7 0.1uF Compensation Capacitor Selection(MLCC) VIN VOUT R4 C7 C1 12V 5/ 3.3/ 2.5/ 1.8/ 1.5V 0.8~2K 0.1µF 330pF 5V 3.3/ 2.5/ 1.8/ 1.5V 0.8~2K 27nF 330pF VIN+12V U1 C2 470uF C3 0.1uF R5 100K 1 FB VSS 2 EN VSS ON/OFF C6 0.1uF 3 COMP Output 4 VCC Output 4. VOUT = VFB × (1+ AP5002 Rev. 8 R1 L1-(WURTH S05100104) 10uH 7 6 5 AP5002 R4 4.7~6.8K Notes: 8 C7 33nF 1 D1 Dii 723 B340A VOUT = 3.3V 2 R1 3.8K C1 330pF C8 0.1uF C4 470uF R2 1.2K ) R2 5 of 10 www.diodes.com FEBRUARY 2009 © Diodes Incorporated AP5002 PWM CONTROL 2A STEP-DOWN CONVERTER Typical Performance Characteristics 570 575 560 Frequency(KHZ) Frequency(KHZ) AP5002 Temperature vs. Frequency (Vout=3.3V; Iout=0.2A) AP5002 Vin vs. Frequency (Vout=3.3V; Iout=0.2A) 550 540 530 545 530 515 500 520 485 510 0 5 10 Vin(V) 15 20 -20 25 0 20 40 60 Temperature( ℃) 80 100 120 AP5002 Temperature vs. FB (Vout=3.3V; Iout=0.2A) AP5002 Vin vs. FB (Vout=3.3V; Iout=0.2A) 0.808 0.82 0.806 0.81 VFB(V) VFB(V) 560 0.804 0.802 0.8 0.79 0.8 0.78 0 5 10 15 Vin(V) 20 25 -20 30 80 Temperature(℃) 130 AP5002 Efficiency 100 90 Vout=5V Efficiency(%) 80 70 Vout=3.3V 60 50 40 30 20 10 0 0 AP5002 Rev. 8 0.5 1 Iout(A) 1.5 2 6 of 10 www.diodes.com FEBRUARY 2009 © Diodes Incorporated AP5002 PWM CONTROL 2A STEP-DOWN CONVERTER Typical Performance Characteristics (Continued) AP5002 Line Regulation 3.35 3.34 3.34 3.33 3.33 Vout(V) Vout(V) AP5002 Load Regulation 3.35 3.32 3.31 3.32 3.31 3.3 0 0.5 1 Iout(A) 1.5 3.3 2 0 5 ICCQ(mA) ICCQ(mA) 4 3 2 1 AP5002 Rev. 8 10 Vin(V) 15 Vin(V) 15 20 25 5 4.5 4 3.5 3 2.5 2 1.5 1 0.5 0 -20 0 5 10 AP5002 Temperature vs. I CCQ (Vout=3.3V) AP5002 Vin vs. ICCQ (Vout=3.3V) 0 5 20 7 of 10 www.diodes.com 0 20 40 60 Temperature( ℃) 80 100 120 FEBRUARY 2009 © Diodes Incorporated AP5002 PWM CONTROL 2A STEP-DOWN CONVERTER Typical Performance Characteristics (Continued) AP5002 Vout Ripple (Vin=12V; Vout=5V; Iout=0.2A) AP5002 Vout Ripple (Vin=12V; Vout=5V; Iout=2A) Test Circuit VCC OUTPUT FB Oscillation open open COMP A EN + - VSS Enable function test VCC OUTPUT OUTPUT COMP EN FB VSS FB COMP EN VCC Feedback function test 22u 6.8K 6.8K 1500p + - A V + VSS - 1.2K Operation function test AP5002 Rev. 8 8 of 10 www.diodes.com FEBRUARY 2009 © Diodes Incorporated AP5002 PWM CONTROL 2A STEP-DOWN CONVERTER Functional Description PWM Control The AP5002 consists of DC/DC converters that employ a pulse-width modulation (PWM) system. In converters of the AP5002, the pulse width varies in a range up 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. RDS(ON) Current Limiting The current limit threshold is set by the internal circuit. Setting the Output Voltage Application circuit item shows the basic application circuit with adjustable output version. The external resistor sets the output voltage according to the following equation: VOUT (V) 5 3.3 2.5 1.8 1.5 1.2 1 R1 (KΩ) 6.4 3.8 2.6 3.3 3.3 3.3 3.3 VRIPPLE = ΔIL × ESR The bulk capacitor’s ESR will determine the output ripple voltage and the initial voltage drop after a high slew-rate transient. An aluminum electrolytic capacitor's ESR value is related to the capacitance and its voltage rating. In most case, higher voltage electrolytic capacitors have lower ESR values. Most of the time, capacitors with much higher voltage ratings may be needed to provide the low ESR values required for low output ripple voltage. MLCC CAP A 22µF MLCC capacitor for most applications is sufficient. PCB Layout Guide If you need low TC & TJ or large PD(Power Dissipation), The dual SW pins(5& 6) 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 R4 to VCC and OCSET pin as closely as possible. 3. Connect ground side of the C2 & D1 as closely as possible. Typical PC Board Layout R2 (KΩ) 1.2 1.2 1.2 2.6 3.7 6.5 13 Inductor Selection For most designs, the operates with inductors of 10µH to 22µH. The inductor value can be derived from the following equation: L= value. For the output capacitor, the ESR value is the most important parameter. The output ripple can be calculated from the following formula. Top Side Layout Guide (VIN − VOUT )TON 2 × ΔIL × fosc 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 2A, ∆IL=0.3A. 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+0.15A). Input Capacitor Selection EL CAP This capacitor should be located close to the IC using short leads and the voltage rating should be approximately 1.5 times the maximum input voltage. The RMS current rating requirement for the input capacitor of a buck regulator is approximately 1⁄2 the DC load current. A low ESR input capacitor sized for maximum RMS current must be used. A 470µF low ESR capacitor for most applications is sufficient. Use vias to conduct the heat into the backside of PCB layer. The PCB heat sink copper area should be solder-painted without masked. This approaches a “best case” pad heat sink. Bottom Side Layout Guide MLCC CAP A 22µF MLCC capacitor for most applications is sufficient. Output Capacitor Selection EL CAP The output capacitor is required to filter the output voltage and provides regulator loop stability. The important capacitor parameters are the 100KHz Equivalent Series Resistance (ESR), the RMS ripples current rating, voltage rating and capacitance AP5002 Rev. 8 9 of 10 www.diodes.com FEBRUARY 2009 © Diodes Incorporated AP5002 PWM CONTROL 2A STEP-DOWN CONVERTER Marking Information ( Top View ) 5 8 Logo G : Green YY : Year : 08, 09,10~ WW : Week : 01~52; 52 represents 52 and 53 week X : Internal Code AP5002 YY WW X X Part Number 1 0.254 0.10/0.20 3.85/3.95 (All Dimensions in mm) 5.90/6.10 Package Information 4 Gauge Plane Seating Plane 0.62/0.82 Detail "A" 7°~9° 0.15/0.25 1.30/1.50 1.75max. 0.35max. 45° 7°~9° Detail "A" 0°/8° 0.3/0.5 1.27typ 4.85/4.95 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. AP5002 Rev. 8 10 of 10 www.diodes.com FEBRUARY 2009 © Diodes Incorporated