5V/100mA PFM Asynchronous Step-up Converter

The HT77xxB series is a set of PFM step-up DC/DC converters with high efficiency and low ripple. The series features extremely low start-up voltage and high output voltage accuracy. They require only few external components to provide a fixed output voltage of 1.8V, 2.2V, 2.7V, 3.0V, 3.3V, 3.7V and 5.0V. CMOS technology ensures low supply current and makes them ideal for battery-operated applications powered from one or more cells.

The HT77xxB series consist of an oscillator, a PFM control circuit, a driver transistor, a reference voltage unit and a high speed comparator. They employ pulse frequency modulation (PFM) for minimum supply current and ripple at light output loading. These devices are available in space saving 3-pin SOT89, 3-pin SOT23 and 5-pin SOT23 packages. For the 5-pin SOT23 package, it also contains a chip enable function to reduce power consumption during shutdown mode.

Features:

• low startup voltage: 0.85V (typical)
• high efficiency up to 80%
• ultra low no load input current
• high output voltage accuracy: ±2.5%
• fixed output voltage: 1.8V
• ultra low shutdown current: 0.1uA (typical)
• package type: SOT89-3 and SOT23-5

Specification:

• input voltage: 0.7V~6.0V
• output voltage: 1.8V
• output current: 0.1A
• switching frequency: 115kHz
• accuracy: VOUT±2.5%
• shutdown current: 1.0μA
• operationn current: 4μA
• efficiency: 80%
• mode: PFM
• case: SOT89