AP1520 PWM CONTROL 2A STEP-DOWN CONVERTER Description Pin Assignments AP1520 consists of step-down switching regulator with PWM control. These devices include a reference voltage source, oscillation circuit, (Top View) error amplifier and internal PMOS. AP1520 provides low-ripple power, high efficiency and excellent FB 1 8 Vss 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. An enable function, an over current protection EN 2 7 Vss and a short circuit protection are built inside, and when OCP or SCP AP1520 happens, the operation frequency will be reduced from 300kHz to OCSET 3 6 Output 30kHz. Also, an internal compensation block is built in to minimum external component count. VCC 4 5 Output With the addition of an internal P-channel Power MOS, a coil, capacitors, and a diode connected externally, these ICs can function SO-8 as step-down switching regulators. They serve as ideal power supply units for portable devices when coupled with the SO-8 package, providing such outstanding features as low current consumption. Applications Since this converter can accommodate an input voltage up to 23V, it is also suitable for the operation via an AC adapter.  PC Motherboard  LCD Monitor Features  Graphic Card  DVD-Video Player  Input Voltage: 3.6V to 23V  Telecom Equipment  Output Voltage: 0.8V to VCC  ADSL Modem  Duty Ratio: 0% to 100% PWM Control  Printer and Other Peripheral Equipment  Oscillation Frequency: 300kHz Typ  Microprocessor Core Supply  Current Limit, Enable Function  Networking Power Supply  Thermal Shutdown Function  Built-in Internal SW P-channel MOS  Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2)  Halogen and Antimony Free.“Green” Device (Note 3) Notes: 1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant. 2. See http://www.diodes.com/quality/lead_free.html for more information about Diodes Incorporated’s definitions of Halogen- and Antimony-free,"Green" and Lead-free. 3. Halogen- and Antimony-free "Green” products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl) and <1000ppm antimony compounds. Typical Applications Circuit L1 VIN Vcc Output VOUT 22µH ROCSET COCSET AP1520 CC 6R.A8K 3K Option Optional + + CIN OCSET FB C COUT 680µF EN VSS - 0.1µF- 470µF CVcc 1R0E0NK D1 RB 1.3K 0.1µF CEN 0.1µF Note: V =V x (1+R /R ) OUT FB A B RB=0.7kΩ to 5kΩ AP1520 1 of 9 December 2017 Document number: DS31174 Rev. 6 - 2 www.diodes.com © Diodes Incorporated

AP1520 Pin Descriptions Pin Number Pin Name Description 1 FB Feedback pin Enable Input pin H: Normal operation 2 EN (Step-down operation) L: Step-down operation stopped (All circuits deactivated) 3 OCSET Add an external resistor to set max output current 4 VCC IC power supply pin 5, 6 Output Switch Pin. Connect external inductor/diode here. Minimize trace area at this pin to reduce EMI 7, 8 VSS GND Pin Functional Block Diagram Output Oscillation Reference Voltage Circuit Source with Soft Start V cc + PWM-Switched FB Control Circuit - Thermal Shutdown 100uA V Vss EN EN OCSET Absolute Maximum Ratings Symbol Parameter Rating Unit VCC VCC Pin Voltage VSS - 0.3 to VSS + 25 V VFB FB Pin Voltage VSS - 0.3 to VCC V VEN EN Pin Voltage VSS - 0.3 to VIN + 0.3 V VOUT Output Pin Voltage VSS - 0.3 to VIN + 0.3 V PD Power Dissipation Internally Limited mW TOP Operating Junction Temperature Range -20 to +125 °C TST Storage Temperature Range -65 to +150 °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. AP1520 2 of 9 December 2017 Document number: DS31174 Rev. 6 - 2 www.diodes.com © Diodes Incorporated

AP1520 Recommended Operating Conditions Symbol Parameter Min Max Unit VIN Input Voltage 3.6 23 V IOUT Output Current 0 1.8 A TA Operating Ambient Temperature -25 +85 °C Electrical Characteristics (VIN = 12V, TA = +25°C, unless otherwise specified.) Symbol Parameter Conditions Min Typ Max Unit VFB Feedback Voltage IOUT = 0.1A 0.784 0.8 0.816 V IFB Feedback Bias Current IOUT = 0.1A — 0.1 0.5 µA ISW Switch Current — 2.5 — — A ISHDN Current Consumption During Power off VEN = 0V — 10 — µA ∆VOUT Line Regulation VIN = 5V to 23V — 1 2 % /VIN ∆VOUT Load Regulation IOUT = 0.1 to 2A — 0.2 0.5 % /VOUT fOSC Oscillation Frequency Measure waveform at Output pin 240 300 360 kHz Frequency of Current Limit or Short fOSC1 Measure waveform at Output pin 10 — — kHz Circuit Protection VIH Evaluate oscillation at Output pin 2.0 — — EN Pin Input Voltage V VIL Evaluate oscillation stop at Output pin — — 0.8 IENH — — 20 — µA EN Pin Input Leakage Current IENL — — -10 — µA IOCSET OCSET Pin Bias Current — 75 90 105 µA tSS Soft-Start Time — 0.3 1 2 ms TSHDN Thermal Shutdown Threshold — — +150 — °C THYS Thermal Shutdown Hysteresis — — +55 — °C VIN = 5V, VFB = 0V — 110 150 RDSON Internal MOSFET RDSON mΩ VIN = 12V, VFB = 0V — 70 100 VIN = 12V, VOUT = 5V EFFI Efficiency — 92 — % IOUT = 2A θJA Thermal Resistance Junction-to-Ambient SO-8 (Note 4) — 134 — oC/W θJC Thermal Resistance Junction-to-Case SO-8 (Note 4) — 22 — oC/W Note: 4. Test condition: Device mounted on FR-4 substrate 2oz copper, minimum recommended pad layout, single side. For better thermal performance, please arrange larger copper pad of layout for heatsink. AP1520 3 of 9 December 2017 Document number: DS31174 Rev. 6 - 2 www.diodes.com © Diodes Incorporated

AP1520 Performance Characteristics AP1520 Vin vs. Frequency AP1520 Vin vs. FB (Vout=3.3V; Iout=0.2A) (Vout=3.3V; Iout=0.2A) 350 0.84 345 0.83 0.82 340 0.81 z) 335 kH V) 0.80 c ( 330 B ( 0.79 os 325 F 0.78 F 320 0.77 0.76 315 0.75 310 0.74 3.6 4 6 8 10 12 14 16 18 3.6 4 6 8 10 12 14 16 18 Vin (V) Vin (V) AP1520 Line Regulation AP1520 Load Regulation (Vin=12V; Iout=0.2A) (Vin=12V) 3.40 5.10 5.09 3.35 5.08 5.07 3.30 V) A) 5.06 ut ( 3.25 ut ( 5.05 Vo Vo 5.04 3.20 5.03 5.02 3.15 5.01 3.10 5.00 3.6 4 6 8 10 12 14 16 18 0.0 1.0 2.0 3.0 4.0 Vin (V) Iout (A) AP1520 Efficiency 100 90 80 ) 70 % y ( 60 nc 50 e ci 40 Effi 30 Vout:5.0V 20 Vout:3.3V 10 0 0.0 0.5 1.0 1.5 2.0 Iout (A) AP1520 4 of 9 December 2017 Document number: DS31174 Rev. 6 - 2 www.diodes.com © Diodes Incorporated

AP1520 Performance Characteristics (Cont.) AP1520 Vout Ripple AP1520 Vout Ripple (V = 12V; V = 3.3V; I = 0.1A) (V = 12V; V = 3.3V; I = 2A) in out out in out out Test Circuit open n o VVCC CC OOUuTtPpUutT FB open scillati A VVC CCC OOUuTtpPuUtT FB O OCSET + OCSET A EN VVS SSS - EN VVS SSS Enable function test Feedback function test VVCC CC OOUuTtpPuUtT FB OCSET + - EN VV SSSS + V - Operation function test AP1520 5 of 9 December 2017 Document number: DS31174 Rev. 6 - 2 www.diodes.com © Diodes Incorporated

AP1520 Functional Description PWM Control The AP1520 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. Under Voltage Lockout The under voltage lockout circuit of the AP1520 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. 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 (90μA 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 current limit threshold is given by the following equation: I R I R PEAK DS(ON) OCSET OCSET (I) I I  PEAK OUT(MAX) 2 where, V V V I IN OUT OUT fsL V IN 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. The above equation is recommended for input voltage range of 5V to 18V. For input voltage lower than 5V or ambient temperature over +100°C, higher ROCSET is recommended. Inductor Selection For most designs, the operation range with inductors is from 22µH to 33µH. The inductor value can be derived from the following equation: V V V L IN OUT OUT fsI V IN Where IL is inductor Ripple Current. Large value inductors lower ripple current and small value inductors result in high ripple current. Choose inductor ripple current approximately 15% of the maximum load current 2A, ∆IL=0.30A. 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 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. Output Capacitor Selection 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 value. For the output capacitor, the ESR value is the most important parameter. The output ripple can be calculated from the following formula. AP1520 6 of 9 December 2017 Document number: DS31174 Rev. 6 - 2 www.diodes.com © Diodes Incorporated

AP1520 Functional Description (Cont.) V ΔI ESR RIPPLE L 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. PCB Layout Guide If you need low TC & TJ or large PD (Power Dissipation), the dual Output pins (5 & 6) and VSS pins (7 & 8) on the SO-8 package are internally connected to die pad, the evaluation board should be allowed for maximum copper area at output pins. 1. Connect FB circuits as closely as possible and keep away from inductor flux for pure VFB. 2. Connect input capacitor to VCC and VSS pin as closely as possible to get good power filter effect. 3. Connect ROCSET to VCC and OCSET pin as closely as possible. 4. Connect ground side of the input capacitor & Schottky & output capacitor as closely as possible and use ground plane for best performance. Ordering Information AP1520 S X - 13 Package Green Packing S : SO-8 L : Lead Free 13 : Tape & Reel G : Green Part Number Suffix Part Number Package Status Package Code Green Quantity 13’’Tape and (Note 5) (Note 6) Tube (Note 5) reel AP1520SG-13 S SO-8 Green 2500 NA -13 In production Notes: 5. All Lead-Free variants are End of life without replacement. 6. For packaging details, go to our website at: https://www.diodes.com/design/support/packaging/diodes-packaging/diodes-package-outlines-and-pad-layouts/. Marking Information (Note 5) (1) SO-8 ( Top View ) 8 5 Logo L : Lead Free G : Green Part Number AP1520 YY : Year : 08, 09,10~ YYWWXX WW : Week : 01~52; 52 represents 52 and 53 week X : Internal Code 1 4 AP1520 7 of 9 December 2017 Document number: DS31174 Rev. 6 - 2 www.diodes.com © Diodes Incorporated

AP1520 Package Outline Dimensions Please see http://www.diodes.com/package-outlines.html for the latest version. SO-8 SO-8 Dim Min Max Typ A 1.40 1.50 1.45 E A1 0.10 0.20 0.15 b 0.30 0.50 0.40 1 c 0.15 0.25 0.20 D 4.85 4.95 4.90 E 5.90 6.10 6.00 E1 3.80 3.90 3.85 b E0 3.85 3.95 3.90 E1 e -- -- 1.27 9° (All sides) 7° 4h5 Q c QhL  00..-66 20 00..-87- 20 000...376525 ° All Dimensions in mm 4°±3° A Gauge Plane Seating Plane R 0.1 e A1 E0 L D Suggested Pad Layout Please see http://www.diodes.com/package-outlines.html for the latest version. SO-8 X1 Dimensions Value (in mm) C 1.27 X 0.802 X1 4.612 Y 1.505 Y1 6.50 Y1 Y C X AP1520 8 of 9 December 2017 Document number: DS31174 Rev. 6 - 2 www.diodes.com © Diodes Incorporated

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