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AS1337

Datasheet - D e t a i l e d D e s c r i p t i o n

8 Detailed Description

and PMOS switches, the device maintains high-efficiency from light to heavy loads.

Modern portable devices frequently spend extended time in low-power or standby modes, switching to high power-

drain only when certain functions are enabled. The AS1337 is ideal for portable devices since they maintain high-

power conversion efficiency over a wide output power range, thus increasing battery life in these types of devices.

In addition to high-efficiency at moderate and heavy loads, the AS1337 includes an automatic powersave mode that

improves efficiency of the power converter at light loads. The powersave mode is initiated if the output load current

falls below a factory programmed threshold.

The Overtemperature protection circuitry turn-off both switches for a short time when the temperature reaches 145ºC

in the device .

Figure 13. AS1337 - Block Diagram

AS1337

+

–

Start Up

OSC

PWM

Control

A/B

MUX

Slope

Compensator

1.2MHz

Ramp

Generator

+

–

Powersave

Operation

Control

–

Shutdown

Control

PWM

Comp

Σ

+

–

1.23V

Ref

Sync Drive

Control

A

B

Good

2.3V

Amp

Shutdown

Powersave

0.35

Ω

0.45

Ω

640k

Ω

1%

1.02M

Ω

1%

4.7µF

3.3V

Output

1µF

1.5V

Single

Cell

* Optional

Current

Sense

80k

Ω

2.5pF

150pF

GND

2

SW

1

4

EN

3

FB

6

VIN

5

VOUT

L1

4.7µH

4

POK