The LTC1871HMS is a wide input range, current mode, boost, flyback or SEPIC controller that drives an N-channel power MOSFET and requires very few external components. 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 50kHz to 1MHz 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 LTC1871HMS 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 LTC1871HMS by connecting the SENSE pin to a resistor in the source of the power MOSFET.
The LTC1871HMS is available in the 10-lead MSOP package.
Vin RangeINTVccFeaturesLTC18712.5V to 36V5.2V-LTC1871-12.5V to 36V5.2VLower Burst Mode Threshold (0.195V vs. 0.3V)LTC1871-76V to 36V7VDrives 6V Gate N-Channel MOSFETsLTC1871X2.5V to 36V5.2V175°C Junction Temp, 100% Tested at 175°CFeature
- 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
- ±1% Internal Voltage Reference
- Micropower Shutdown: IQ = 10μA
- Programmable Operating Frequency (50kHz to 1MHz) with One External Resistor
- Synchronizable to an External Clock Up to 1.3 × fOSC
- User-Controlled Pulse Skip or Burst Mode® Operation
- Internal 5.2V Low Dropout Voltage Regulator
- Output Overvoltage Protection
- Capable of Operating with a Sense Resistor for High Output Voltage Applications
- Small 10-Lead MSOP Package
Applications
- Telecom Power Supplies
- Portable Electronic Equipment
(Picture: Pinout)
