AS1302 Step-Up Converter IC

Description

The AS1302 is a 30mA inductorless boost converter using a double H-bridge charge-pump topology with two external flying capacitors. The AS1302 charge pump features 1:2 and 2:3 operation modes as well as a 1:1 operation mode where the input is directly connected to the output.

The AS1302 runs on a 1.2MHz fixed frequency and is utilized with a low noise regulation scheme to allow usage together with sensitive RF circuitry from the same battery supply. Additionally to increase efficiency, the AS1302 switches to 49kHz at light loads.

Designed to reside in portable and space limited equipment, the 1.2MHz charge pump converts a 2.9V to 5.15V input to regulated 5V output with 3% accuracy.

The shutdown function reduces the supply current to <1μA and disconnects the load from the output. The integrated soft-start circuitry prevents high inrush currents being drawn from the battery during start-up.

The AS1302 includes built-in under-voltage lockout, short circuit-, and thermal protection circuitry.

The AS1302 is available in TDFN (3x3x0.8mm) 10-pin and an extremely small 1.2x1.2mm WL-CSP 8-bumps package with 0.4mm pitch.

Key Features

• Up to 90% Efficiency
• 2.9V to 5.15V Input Voltage
• Regulated 5V Output
• Automatic Mode Switching
• <1μA Shutdown Current
• Startup with Full Load (within 1ms)
• Up to 30mA Load Current
• Short Circuit Protection
• Output Disconnected during Shutdown
• Soft-Start
• No Inductor Required
• Small External Components required
  • (COUT =2.2μF, CFLY =220nF)
• Low Noise Fixed Frequency (1.2MHz, 49kHz)
• Charge Pump:
  • 1:1 Battery Feed Through Mode
  • 2:3 Single Phase Mode
  • 1:2 Single Phase Mode
• Package Options:
  • TDFN (3x3x0.8mm) 10-pin
  • WL-CSP 8-bumps with 0.4mm Pitch

Applications

The device is ideal for two or three AA cells or a single Li-Ion battery cell to 5V conversion, mobile phones, portable instruments, microprocessor based systems and remote data-acquisition systems.

Block Diagram