AS1325 Step-Up Converter IC

Description

The AS1325 is a high-efficiency step-up DC-DC converter designed to generate a fixed output voltage of +3.3V or +5V.

The AS1325 achieves an efficiency of up to 96% and the minimum input voltage is 1.5V. The AS1325-BSTT-33 delivers up to 300mA output current at the fixed output voltage of +3.3V (@ 2V VBATT). With the fixed output voltage of +5V the AS1325-BSST-50 supplies up to 185mA output current (@ 2V VBATT).

In order to save power the AS1325 features a shutdown mode, where it draws less than 1μA. In shutdown mode the battery is connected directly to the output enabling the supply of real-time-clocks.

The AS1325 provides a power-on reset output that goes high-impedance when the output reaches 90% of its regulation point.

The SHDNN trip threshold of the AS1325 can be used as an input voltage detector that disables the device when the battery voltage falls to a predetermined level.

An internal synchronous rectifier is included.

The AS1325 is available in a 6-pin SOT23 package.

Key Features

• Input Voltage: 1.5 to 3.5V
• Fixed Output Voltage: 3.3V (AS1325-BSTT-33) or 5V (AS1325-BSST-50)
• Output Current:
  • Up to 300mA (AS1325-BSTT-33) @ 2V VBATT
  • Up to 185mA (AS1325-BSST-50) @ 2V VBATT
• Internal Synchronous Rectifier
• Shutdown Mode Supply Current: Less Than 1µA
• Efficiency: Up to 96%
• Accurate Shutdown Low-Battery Cutoff Threshold
• Battery Input Connected to OUT in Shutdown Mode for Backup Power
• Antiringing Control Minimizes EMI
• Ripple Reduction at Light Loads
• 6-pin SOT23 Package

Applications

The AS1325 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, cordless phones, and PC cards.

The device is also perfect as a local supply or as a battery backup.

Block Diagram