AS1337 Datasheet, PDF (1/14 Pages) ams AG – 200mA, DC-DC Step-Up Converter with Buck Mode

Datasheet
AS1337
200mA, DC-DC Step-Up Converter with Buck Mode
1 General Description
The AS1337 is a synchronous, fixed frequency,
highefficiency DC-DC boost converter capable of
supplying 3.3V @ 200mA from two AA Cells. Com-
pact size and minimum external parts require-
ments make these devices perfect for modern
portable devices. The AS1337 offers automatic
powersave mode to increase efficiency at light
loads. For input voltages higher than VOUT the
AS1337 will switch in a step down mode, so that a
Buck Boost function is realized.
The AS1337A offers a shutdown mode where the
battery is connected directly to the output enabling
the supply of real-time-clocks or memories.
The AS1337 offers a POK (open-drain) feature
which detects output power fail of 10%.
The AS1337 is available in a TDFN (3x3mm) 8-pin
package.
2 Key Features
! Input Voltage Range: 0.65V to 4.5V
! Low Start-Up Voltage: 0.85V
! Output Voltage Range: 2.5V to 5.0V
! Delivers 200mA @ 3.3V (from two AA Cell)
! up to 97% Efficiency
! High-Speed Fixed-Frequency: 1.2MHz
! Single-Cell Operation
! Internal PMOS Synchronous Rectifier
! Automatic Powersave Operation
! Anti-Ringing Control Minimizes EMI
! Logic Controlled Shutdown (< 1µA)
! TDFN (3x3mm) 8-pin Package
3 Applications
The AS1337 is ideal for low-power applications
where ultra-small size is critical as in medical diag-
nostic equipment, hand-held instruments, pagers,
digital cameras, remote wireless transmitters, MP3
players, LCD bias supplies, cordless phones, GPS
receivers, and PC cards.
Figure 1. AS1337 - Typical Application Diagram – Dual Cell to 3.3V Synchronous Boost Converter
3.6V
Buck Mode
V_OUT=3.3V
V_IN Curve
Boost Mode
1.6V
L1
4.7µH
VIN = 2xAA
LX
1.6V to 3.6V
C_IN
10µF
VIN
On
Off
EN
GND
AS1337
VOUT
FB
POK
PGND
VOUT = 3.3V
C_OUT
22µF
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