AP1605 PWM/PFM DUAL-MODE STEP-DOWN SWITCHING REGULATOR Description Pin Assignments AP1605 consists of CMOS step-down switching regulator with PWM/PFM dual mode control. These devices include a reference (Top View) voltage source, oscillation circuit, error amplifier, internal PMOS and etc. FB 1 8 Vss AP1605 provides low-ripple power, high efficiency, and excellent transient characteristics. The PWM/PFM control circuit is able to vary Vss 2 7 CE the duty ratio linearly 0%~0.25% (PFM) and 25%~100% (PWM). 3 6 SW Vcc With the addition of an internal P-channel Power MOS, a coil, capacitors, and a diode connected externally, these ICs can function 4 5 PVcc SW as step-down switching regulators. They serve as ideal power supply units for portable devices when coupled with the SO-8 mini-package, providing such outstanding features as low current consumption. SO-8 Since this converter can accommodate an input voltage of up to 7V, it is also ideal when operating via an AC adapter. Applications Features On-board Power Supply of Battery Devices for Portable Low Current Consumption: Telephones, Electronic Notebooks, PDA, and Other Hand-held Sets In Operation: 100A max. Power Supplies for Audio Equipment, Including Portable CD Power Off: 2A max. Players and Headphone Stereo Equipment Input Voltage: 2.5V to 7V Fixed Voltage Power Supply for Cameras, Video Equipment and Adjustable Version (2.5%) Communications Equipment PWM/PFM Dual Mode Power Supplies for Microcomputers Oscillation Frequency: 300kHz (Typ.) Conversion from Four Ni-H or Ni-Cd Cells or With a Power-off Function Two Lithium-ion Cells to 3.3V/3V Built-in Internal SW P-channel MOS Conversion of AC Adapter Input to 5V/3V 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 AP1605 Typical Applications Circuit (1) Normal Application OUT PV CC SW C R C A R VCC FB + AP1605 R VCC B =~200K - D1 C VCC R CE 100K CE V SS C CE 0.1F RA V VFB (1 ) OUT RB (2) Application with Short Circuit Protection VIN : 2.5V~7V VOUT : 1.8V PV CC SW DVCC 1N4148 for above 5V Vin and C R Schottky for below 5V Vin C A AP 1605 VCC FB RON/OFF CON/OFF + 3.5M 0.2uF COUTPUT RB CE 100 uF V SS =~10K - D1 RBias RSENCE 10M 1M RA CPVCC CVCC Vout VFB (1 ) 100 uF 0.1uF RB 2 of 7 AP1605 December 2017 Diodes Incorporated www.diodes.com Document number: DS31021 Rev. 3 - 2