Wide Input Range, No R Current Mode Boost, Flyback and SEPIC Controller

LTC1871X is a wide input range, current mode, boost, flyback or SEPIC controller that drives an N-channel power MOSFET. LTC1871X is rated to 175°C junction temperature and is 100% tested at 175°C. Intended for low to medium power applications, it eliminates the need for a current sense resistor by utilizing the power MOSFET’s on-resistance, thereby maximizing efficiency.

The IC’s operating frequency can be set with an external resistor over a 65kHz to 900kHz range, and can be synchronized to an external clock using the MODE/SYNC pin. Burst Mode operation at light loads, a low minimum operating supply voltage of 2.5V and a low shutdown quiescent current of 10μA make the LTC1871X ideally suited for battery-operated systems.

For applications requiring constant frequency operation, Burst Mode operation can be defeated using the MODE/SYNC pin. Higher output voltage boost, SEPIC and flyback applications are possible with the LTC1871X by connecting the SENSE pin to a resistor in the source of the power MOSFET. The LTC1871X is available in the 10-lead MSOP package.

VIN Range

INTVCC

Features

LTC1871

2.5V to 36V

5.2V

LTC1871-1

2.5V to 36V

5.2V

Lower Burst Mode Threshold (0.195V vs. 0.3V)

LTC1871-7

6V to 36V

7V

Drives 6V Gate N-Channel MOSFETs

LTC1871X

2.5V to 36V

5.2V

175°C Junction Temp, 100% Tested at 175°C

Applications

* Telecom Power Supplies

* Portable Electronic Equipment

* High Efficiency (No Sense Resistor Required)

* Wide Input Voltage Range: 2.5V to 36V

* Current Mode Control Provides Excellent Transient Response

* High Maximum Duty Cycle (92% Typ)

* ±2% RUN Pin Threshold with 100mV Hysteresis

* ±2% Internal Voltage Reference

* Micropower Shutdown: IQ = 10μA

* Programmable Operating Frequency (65kHz to 900kHz) with One External Resistor