10

AAT1130

2.5MHz 400mA Step-Down DC/DC Converter

DATA SHEET

Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com

201977B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 15, 2013

Functional Description

The AAT1130 is a high performance 400mA 2.5MHz

(maximum switching frequency during steady-state

operation) monolithic step-down converter. It minimizes

external component size, enabling the use of a tiny 0603

inductor that is only 1mm tall, and optimizes efficiency

over the complete load range. Apart from the small

bypass input capacitor, only a small L-C filter is required

at the output. Typically, a 1μH inductor and a 4.7μF

ceramic capacitor are recommended for <1.2V output

voltage applications (see table of values).

are required. Output voltage is programmed with exter-

nal feedback resistors, ranging from 0.6V to 1.8V. An

additional feed-forward capacitor can also be added to

the external feedback to provide improved transient

response (see Figure 1).

The input voltage range is 2.7V to 5.5V. The converter

efficiency has been optimized for all load conditions,

ranging from no load to 400mA.

The internal error comparator and incorporated compen-

sation provide excellent transient response, load, and line

regulation. Soft-start eliminates any output voltage over-

shoot when the enable or the input voltage is applied.

Control Loop

The AAT1130 uses a current-mode control scheme that

allows it to operate at very high switching frequencies.

The current-mode control scheme operates with a pre-

dicted on-time for a given output to input voltage ratio.

The on-time varies inversely proportional to the input

voltage and proportional to the output voltage giving the

regulator a fixed switching frequency when in steady-

state. This allows the use of very small external inductor

and capacitor. The small size coupled with the low quies-

Functional Block Diagram

Shoot

Through

Protection

Error

Comparator

+

-

Current

Limit

Comparator

EN

Current

Sense

Amplifier

Soft-Start

Control and

FET Driver

Logic Circuitry

VOUT

FB

VCC

VP

GND

GND

LX