AP1605

PWM/PFM Dual-mode Step-Down Switching Regulator

This datasheet contains new product information. Anachip Corp. reserves the rights to modify the product specification without notice. No liability is assumed as a result of the use of

this product. No rights under any patent accompany the sale of the product.

Rev. 1.1 Jan 18, 2005

1/6

Features

- Low current consumption:

In operation: 100µA max.

Power off: 2µA max.

- Input voltage: 2.5V to 7V.

Adjustable version (+2.5%)

- PWM/PFM dual Mode

- Oscillation frequency: 300KHz (Typ.)

- With a power-off function.

- Built-in internal SW P-channel MOS

- SOP-8L/TSSOP-8L Package.

Applications

- On-board power supplies of battery devices for

portable telephones, electronic notebooks, PDA,

and other hand-held sets.

- Power supplies for audio equipment, including

portable CD players and headphone stereo

equipment.

- Fixed voltage power supply for cameras, video

equipment and communications equipment.

- Power supplies for microcomputers.

- Conversion from four Ni-H or Ni-Cd cells or two

lithium-ion cells to 3.3V/3V.

- Conversion of AC adapter input to 5V/3V.

General Description

AP1605 consists of CMOS step-down switching

regulator with PWM/PFM dual mode control. These

devices include a reference voltage source, oscillation

circuit, error amplifier, internal PMOS and etc.

AP1605 provides low-ripple power, high efficiency,

and

excellent

transient

characteristics.

The

PWM/PFM control circuit is able to very the duty ratio

linearly 0%~0.25% (PFM) and 25%~100% (PWM).

With the addition of an internal P-channel Power MOS,

a coil, capacitors, and a diode connected externally,

these ICs can function as step-down switching

regulators. They serve as ideal power supply units for

portable devices when coupled with the SOP–8L

mini-package, providing such outstanding features as

low current consumption. Since this converter can

accommodate an input voltage of up to 7V, it is also

ideal when operating via an AC adapter.

Pin Assignments

1

2

3

4

8

7

6

5

FB

SW

Vcc

AP1605

SW

Vss

Vss

PVcc

CE

SOP-8L

1

3

2

4

8

6

7

5

Vss

CE

CE

FB

SW

PVcc

PVcc

Vcc

AP1605

TSSOP-8L

Pin Descriptions

Pin No.

Pin

Name SOP TSSOP

Description

FB

1

4

Feedback pin

CE

2

2、3

Chip Enable:

H: Enable

L: Disable

Vcc

3

5

IC signal power supply pin,

add a 10Ω resistor to PVcc

and a 0.1µF capacitor to

GND.

PVcc

4

6、7

IC power supply pin

SW

5、6

8

Switch Pin. Connect external

inductor/diode here.

Minimize trace area at this

pin to reduce EMI.

Vss

7、8

1

GND Pin