Diodes AP3581A/B/C - Manual

Data Sheet
Single Phase Synchronous Buck PWM Controller AP3581A/B/C
Oct. 2011 Rev. 1. 0 BCD Semiconductor Manufacturing Limited
1
General Description
The
1 AP3581A/B/C 1 is 1 a 1 compact 1 synchronous-rect
ified buck controller specifically designed to operate
from 5V/12V supply and deliver high-quality output
voltage as low as 0.6V (AP3581A) or 0.8V
(AP3581B/C). The AP3581A/B/C operates at fixed
frequency of 300kHz (AP3581A/B) or 200kHz
(AP3581C) and provides an optimal level of
integration to reduce size and cost of the power
supply.
This controller integrates internal MOSFET drivers
that support 12V+12V bootstrapped voltage for high-
efficiency power conversion. The bootstrap diode is
built-in to simplify the circuit design and minimize
external part count.
This controller provides single feedback loop,
voltage-mode control with fast transient response.
The error amplifier features a 10MHz gain-bandwidth
product and 6V/µs slew rate which enables high
converter bandwidth for fast transient performance.
Other features include internal soft-start, under
voltage protection, over current protection and
shutdown function. With afore-mentioned functions,
this part provides customers a compact, high
efficiency, well-protected and cost-effective
solutions.
The AP3581A/B/C is available in PSOP-8 package.
Features
• Supply Voltage: 5V/12V
• V
IN
Input Range: 3.0V to 13.2V
• 0.6V/0.8V to 80% of V
IN
Output Range
• Internal Reference: 0.6V/0.8V
• Simple Single-loop Control
• Voltage-mode PWM Control
• Duty Cycle: 0% to 80%
• Fast Transient Response
• 10MHz High-bandwidth Error Amplifier with
6V/µs Slew Rate
• Fixed Oscillator Frequency: 300kHz/200kHz
• Lossless, Programmable Over Current Protection
(Uses Lower MOSFET R
DS(ON)
)
• Start-up into Pre-biased Output
• Built-in Thermal Shutdown
• Built-in Soft-start
• Over Current/Voltage Protection
• Under Voltage Protection
• Integrated Boot Diode
Applications
• Power Supplies for Microprocessors/Peripherals
• PCs, Embedded Controllers, Memory Supplies
• DSP and Core Communications Processor
Supplies
• Subsystem Power Supplies
• PCI, AGP, Graphics Cards, Digital TV
• SSTL-2 and DDR/2/3 SDRAM Bus Termination
Supply
• Cable Modems, Set Top Boxes, and DSL
Modems
• Industrial Power Supplies and General Purpose
Supplies
• 5V/12V Input DC-DC Regulators
• Low-voltage Distributed Power Supplies
Figure 1. Package Type of AP3581A/B/C
PSOP-8