NOT RECOMMENDED FOR NEW DESIGN CONTACT US AP1533 PWM CONTROL 1.8A STEP-DOWN CONVERTER Description Pin Assignments AP1533 consists of step-down switching regulator with PWM control. ( T o p V ie w ) These devices include a reference voltage source, oscillation circuit, error amplifier, internal PMOS. 1 8 V FB SS AP1533 provides low-ripple power, high efficiency, and excellent 2 7 V SS EN AP1533 transient characteristics. The PWM control circuit is able to vary the 3 6 O u tp u t O C S E T 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 V 4 5 CC O u tp u t overshoot at startup. An enable function, an over current protect function and a short circuit protect function are built inside, and when S O P -8 L OCP or SCP happens, the operation frequency will be reduced from 300KHz to 50KHz. Also, an internal compensation block is built in to Applications minimum external component count. PC Motherboard LCD Monitor With the addition of an internal P-channel Power MOS, a coil, Graphic Card capacitors, and a diode connected externally, these ICs can function as DVD-Video Player step-down switching regulators. They serve as ideal power supply units Telecom Equipment for portable devices when coupled with the SOP-8L mini-package, ADSL Modem providing such outstanding features as low current consumption. Since Printer and other Peripheral Equipment this converter can accommodate an input voltage up to 23V, it is also Microprocessor core supply suitable for the operation via an AC adapter. Features Input voltage: 4V to 23V Output voltage: 0.8V to V CC Output current: 1.8A up to peak 2A Duty ratio: 0% to 99% PWM control Oscillation frequency: 300KHz typ. Soft-start like, Current limit and Enable function Thermal Shutdown function Built-in internal SW P-channel MOS SOP-8L: Available in Green Molding Compound (No Br, Sb) Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2) Halogen and Antimony Free. Green Device (Note 3) For automotive applications requiring specific change control (i.e. parts qualified to AEC-Q100/101/200, PPAP capable, and manufactured in IATF 16949 certified facilities), please contact us or your local Diodes representative. AP1533 Typical Application Circuit V = 5 V /1 .8 A O U T L 1 V V c c O u tp u t IN 33uH R A R C C O C S E T O C S E T C 6 .8 K AP1533 3 .3 K O p tio n O p tio n a l + + FB C O C S E T C C IN O U T 0 .1uF 470uF 470uF V EN - - SS R EN R C V c c B 100 K D 1* 1 .3 K 0 .1uF C EN 0 .1uF V = V x (1 + R / R B ) O U T FB A R = 0 .7 K ~ 5 K o h m B * S u g g e s te d D io d e s In c o rp o ra te d P o w e r S c h o ttk y P /N : B340 s e rie s o r P D S 340 . Pin Descriptions Pin Name Pin No. Description FB 1 Feedback pin Power-off pin H: Normal operation EN 2 (Step-down operation) L: Step-down operation stopped (All circuits deactivated) OCSET 3 Add an external resistor to set max output current 4 IC power supply pin VCC Output 5, 6 Switch Pin. Connect external inductor/diode here. Minimize trace area at this pin to reduce EMI V 7, 8 GND Pin SS 2 of 10 AP1533 March 2020 Diodes Incorporated www.diodes.com Document number: DS31192 Rev. 6 - 3