AP3428/A 1.5MHZ, 1A STEP-DOWN DC-DC BUCK CONVERTER Description Pin Assignments The AP3428/A is a 1A step-down DC-DC converter. At heavy load, the constant-frequency PWM control performs excellent stability and (Top View) transient response. No external compensation components are required. The AP3428/A supports a range of input voltages from 2.5V to 5.5V, allowing the use of a single Li+/Li-polymer cell, multiple Alkaline/NiMH cell, and other standard power sources. The output voltage is adjustable from 0.6V to the input voltage. The AP3428/A employs internal power switch and synchronous rectifier to minimize external part count and realize high efficiency. During shutdown, the input is disconnected from the output and the shutdown current is less than TSOT25/TSOT25 (Type SM) for AP3428 1A. Other key features include over-temperature and short circuit (Top View) protection, and under-voltage lockout to prevent deep battery discharge. The AP3428/A delivers 1A maximum output current while consuming only 40A of no-load quiescent current. Ultra-low R integrated DS(ON) MOSFETs and 100% duty cycle operation make the AP3428/A an ideal choice for high output voltage, high current applications which require a low dropout threshold. Pulse skip mode allows to maintain high efficiency at light-load conditions. TSOT25/TSOT25 (Type SM) for AP3428A The AP3428/A is available in TSOT25, TSOT25 (Type SM), U- DFN2020-6 (Type J) packages. (Top View) Features Output Current: Up to 1A Output Voltage: 0.6V to V IN Input Voltage: 2.5V to 5.5V 0.6V Reference Voltage with 2% Precision 40A (typ) No Load Quiescent Current Shutdown Current: <1A 100% Duty Cycle Operation 1.5MHz Switching Frequency U-DFN2020-6 (Type J) Internal Soft Start No External Compensation Required Current Limit Protection Applications Thermal Shutdown TSOT25, TSOT25 (Type SM), U-DFN2020-6 (Type J) Packages Post DC-DC Voltage Regulation Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2) Set Top Boxes Halogen and Antimony Free. Green Device (Note 3) Notebook Computer For automotive applications requiring specific change PAD 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. AP3428/A AP3428/A Typical Applications Circuit V =2.5V to 5.5V IN VIN C IN L1 2.2mH 1 0 mF V =1.8V OUT LX R1 C1 C OUT GND 22pF 300k 10mF FB EN ON OFF R2 150k Pin Descriptions Pin Number Pin TSOT25/ TSOT25 TSOT25/ TSOT25 Function U-DFN2020-6 Name (Type SM) (Type SM) (Type J) for AP3428 for AP3428A Enable control input. Force this pin voltage above 1.5V enables 1 3 2 EN the chip, and below 0.4V shuts down the device. 2 2 5 GND Ground pin The drains of the internal main and synchronous power 3 5 4 LX MOSFET. 4 1 3 VIN Bias supply. Chip main power supply pin Feedback voltage to internal error amplifier, the threshold 5 4 6 FB voltage is 0.6V. 1 NC NC 2 of 14 May 2021 AP3428/A Diodes Incorporated www.diodes.com Document number: DS37417 Rev. 5 - 2