AS1322 Step-Up Converter IC

Description

The AS1322A and the AS1322B are synchronous, fixed frequency, very high-efficiency DC-DC boost converters capable of supplying 3.3V at 150mA 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:

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.

The AS1322 is available in a 6-pin TSOT-23 package.

Key Features

• Input Voltage: 0.65 to 5.0V
• Output Range: 2.5 to 5.0V
• 95% Efficiency
• Delivers 150mA @ 3.3V (from Single AA Cell)
• Delivers 500mA @ 3.3V (from Two AA Cells)
• High-Speed Fixed-Frequency: 1.2MHz
• Internal PMOS Synchronous Rectifier
• Automatic Powersave Operation (AS1322A)
• Fixed Frequency Operation (AS1322B)
• Anti-Ringing Control Minimizes EMI
• Logic Controlled Shutdown (< 1μA)
• 6-pin TSOT-23 Package

Applications

The AS1322 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.

Block Diagram