www.ams.com/DC-DC_Step-Up/AS1340 Revision 1.20 1 - 17
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 powe r-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 V
IN
- 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
V
IN = 2.7V to
5.5V
3
L1
6
LX
VCC
V
IN = 2.7V to
5.5V
VIN = 2.7V to
~V
OUT
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
