LTC1751 Micropower, Regulated Charge Pump DC/DC Converters
The LTC1751 family are micropower charge pump DC/DC converters that produce a regulated output voltage at up to 100mA. The input voltage range is 2V to 5.5V. Extremely low operating current (20µA typical with no load) and low external parts count (one flying capacitor and two small bypass capacitors at VIN and VOUT) make them ideally suited for small, battery-powered applications.
The LTC1751 family operate as Burst Mode™ switched capacitor voltage doublers to achieve ultralow quiescent current. They have thermal shutdown capability and can survive a continuous short circuit from Vout to GND. The PGOOD pin on the LTC1751-3.3 and LTC1751-5 indicates when the output voltage has reached its final value and if the output has an undervoltage fault condition. The FB pin of the adjustable LTC1751 can be used to program the desired output voltage or current. An optional soft-start capacitor may be used at the SS pin to prevent excessive inrush current during start-up.
The LTC1751 family is available in an 8-pin MSOP package.
- Li-Ion Battery Backup Supplies
- Local 3V and 5V Conversion
- Smart Card Readers
- PCMCIA Local 5V Supplies
- White LED Backlighting
Features and Benefits
- 5V Output Current: 100mA (VIN ≥ 3V)
- 3.3V Output Current: 80mA (VIN ≥ 2.5V)
- Ultralow Power: 20µA Quiescent Current
- Regulated Output Voltage: 3.3V ±4%, 5V ±4%, ADJ
- VIN Range: 2V to 5.5V
- 800kHz Switching Frequency
- No Inductors
- Very Low Shutdown Current: <2µA
- Shutdown Disconnects Load from VIN
- PowerGood/Undervoltage Output
- Adjustable Soft-Start Time
- Short-Circuit/Thermal Protection