Diodes Incorporated

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AP3429 (Not Recommended for new design)

NRND = Not Recommended for New Design

1.0MHz, 2A Step-Down DC-DC Buck Converter

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The AP3429/A is a 2A step-down DC-DC converter. At heavy load, the constant frequency PWM control performs excellent stability and transient response. No external compensation components are required.

The AP3429/A supports a range of input voltages from 2.7V 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 AP3429/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 1μA. Other key features include over temperature and short-circuit protection, and undervoltage lockout to prevent deep battery discharge.

The AP3429/A delivers 2A maximum output current while consuming only 90μA of no-load quiescent current. Ultra-low RDS(ON) integrated MOSFETs and 100% duty cycle operation make the AP3429/A an ideal choice for high output voltage, high current applications which require a low dropout threshold.

The AP3429/A is available in TSOT25 package.


  • Output Current: Up to 2A
  • Output Voltage: 0.6V to VIN
  • Input Voltage: 2.7V to 5.5V
  • Shutdown Current: <1μA
  • 100% Duty Cycle Operation
  • 1MHz Switching Frequency
  • Internal Soft Start
  • No External Compensation Required
  • Short-Circuit Protection
  • AP3429: Latch Off Protection
  • AP3429A: Hiccup Mode Protection
  • Overvoltage Protection
  • AP3429: Latch Off Protection
  • AP3429A: No Latch Off Protection
  • Thermal Shutdown
  • TSOT25 package
  • 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-Q100/101/104/200, PPAP capable, and manufactured in IATF 16949 certified facilities), please contact us or your local Diodes representative. https://www.diodes.com/quality/product-definitions/


  • 5V or 3.3V points of load conversions
  • Telecoms/networking equipment
  • Set-top boxes
  • Storage equipment
  • Video cards
  • DDR power supplies

Product Specifications

Product Parameters

Compliance(Only Automotive supports PPAP) Standard
Frequency Typ (kHz) 1000
HS RDS(ON) (mΩ) 110
LS RDS(ON) (mΩ) 80
Maximum Input Voltage (V) 5.5
Maximum Output Voltage (V) VIN
Minimum Input Voltage (V) 2.7
Minimum Output Voltage (V) 0.6
Output Current (A) 2
Quiescent Current Typ (µA) 0.1
Shutdown Current Typ (µA) 0.1
Type Buck

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