www.ams.com/DC-DC_Step-Up/AS1340

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AS1340

50V, Micropower, DC-DC Boost Converter

1 General Description

The AS1340 boost converter contains a 1.4A internal switch in a tiny

TDFN-8 3x3mm package. The device operates from a 2.7 to 5.5V

supply, and can boost voltages up to 50V output.

The output voltage can easily be adjusted by an external resistor

divider.

The AS1340 uses a unique control scheme providing the highest

efficiency over a wide range of load conditions. An internal 1.4A

MOSFET reduces external component count, and a fixed high

switching frequency (1MHz) allows for tiny surface-mount

components.

The AS1340 also features power-OK circuitry which monitors the

output voltage.

Additionally the AS1340 features a low quiescent supply current and

a shutdown mode to save power. During shutdown an output

disconnect switch separates the input from the output.

The AS1340 is ideal for LCD or OLED panels with low current

requirements and can also be used in a wide range of other

applications.

The device is available in a low-profile TDFN-8 3x3mm package.

Figure 1. AS1340 - Typical Application Diagram

2 Key Features



2.7V to 50V Adjustable Output Voltage



2.7V to 50V Input Voltage Range



2.7V to 5.5V Supply Voltage Range



High Output Currents:

- 100mA @ 12V from 3.3V VIN

- 50mA @ 24V from 3.3V VIN

- 30mA @ 36V from 3.3V VIN



Efficiency: Up to 93%



Switching Frequency: 1MHz



Output Disconnect



Power-OK Output



Operating Supply Current: 30µA



Shutdown Current: 0.1µA



TDFN-8 3x3mm Package

3 Applications

The device is ideal for OLED display power supply, LED power

supply, LCD bias generators, mobile/cordless phones, palmtop

computers, PDAs and organizers, handy terminals or any other

portable, battery-powered device.

VIN

= 2.7V

to 5.5V

1

EN

3

SWVIN

2

VCC

8

FB

4

POK

5

LX

On

Off

R2

R1

VOUT = > VIN to 50V

AS1340

L1

4.7µH

CIN

COUT

6

SWOUT

7, 9

GND

3

L1

6

LX

VCC

VIN = 2.7V to

5.5V

3

L1

6

LX

VCC

VIN = 2.7V to

5.5V

VIN = 2.7V to

~VOUT

If not needed the output disconnect switch can be left unconnected which will also increase the efficiency.

Additionally the supply of the chip can be split to allow higher supply voltages for the coil. In this case the output disconnect switch must not be used.

VOUT

VOUT