
A S1 3 2 9
L o w Vo lt a g e, M i c ro p o w e r, D C- DC St ep - U p C o n v e r te r s
1 General Description
The AS1329A, AS1329B and the AS1329C are synchronous, fixed
frequency, very high-efficiency DC-DC boost converters capable of
supplying 3.3V at 160mA from a single AA-supply. Compact size and
minimum external parts requirements make these devices perfect for
modern portable devices.
High-speed switching frequency (1.2MHz) and internally
compensated PWM current mode design provide highly-reliable DC-
DC conversion, especially when driving white LEDs. The converters
are available as the standard products listed in Table 1 .
2 Key Features
Low Start-Up Voltage: 0.85V
Output Range: 2.5V to 5.0V
Single-Cell Operation
Operating with coils down to 2.2μH
Delivers 160mA @ 3.3V (from Single AA Cell)
Delivers 220mA @ 5.0V (from Two AA Cells)
Table 1. Standard Products
Model
Light Load Switching
Delivers 570mA @ 3.3V (from Two AA Cells)
AS1329A
AS1329B
AS1329C
Medium Load
Automatic Powersave Operation
Light Load Automatic Powersave Operation
Continuous Switching
95% Efficiency
High-Speed Fixed-Frequency: 1.2MHz
Internal PMOS Synchronous Rectifier
Automatic Powersave Operation (AS1329A&B)
The devices contain two internal MOSFET switches: one NMOS
switch and one PMOS synchronous rectifier. Anti-ringing control
circuitry reduces EMI by damping the inductor in discontinuous
mode, and the devices exhibit extremely low quiescent current (<
1μA) in shutdown.
In shutdown mode the battery is connected directly to the output
enabling the supply of real-time-clocks. The AS1329 is available in a
6-pin TSOT-23 package.
Figure 1. Typical Application Diagram – Single Cell to 3.3V
Synchronous Boost Converter
L1
4.7μH
1
SW
Continuous Switching at Light Loads (AS1329C)
Logic Controlled Shutdown (< 1μA)
6-pin TSOT-23 Package
3 Applications
The AS1329 is ideal for low-power applications where ultra-small
size is critical as in medical diagnostic equipment, hand-held
instruments, pagers, digital cameras, remote wireless transmitters,
MP3 players, LCD bias supplies, cordless phones, GPS receivers,
and PC cards.
AA Battery
C 1
10μF
6
VIN
AS1329
5
VOUT
R 1
1.02M ?
1%
C 2
10μF
V OUT
3.3V
160mA
On
Off
4
SHDNN
3
FB
www.ams.com/DC-DC_Step-Up/AS1329
2
GND
Revision 1.12
R 2
604k ?
1%
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