LTC7149EFE

LTC7149 is a high-voltage synchronous inverting step-down DC/DC regulator designed for positive-to-negative voltage conversion. E stands for extended commercial temperature grade specification. FE refers to thermally enhanced 28-lead TSSOP surface mount package with exposed thermal pad, shipped in tube packaging for prototype validation and small batch production assembly.

This monolithic synchronous buck converter is dedicated to generating negative output voltages, supporting an ultra-wide input voltage range from 3.4 V up to 60 V. It delivers adjustable negative output ranging from 0 V down to -28 V, with a maximum continuous inductor current of 4 A. Output voltage is precisely programmed via a single external resistor, achieving tight output accuracy of ±0.8% across full operating conditions.

Both top and bottom N-channel power MOSFETs are fully integrated inside the chip, with typical on-resistance of 110 mΩ and 50 mΩ respectively, enabling peak power conversion efficiency up to 92%. Multiple operation modes are selectable: Burst Mode for ultra-high light-load efficiency, forced continuous mode for low noise and minimal output ripple, plus external clock synchronization function to eliminate switching frequency interference between multiple power supplies.

Switching frequency can be configured from 300 kHz to 3 MHz through an external resistor, allowing designers to choose small-sized inductors and capacitors for compact power solutions. Key power consumption parameters include 440 μA regulated quiescent current under no-load condition and only 15 μA shutdown current. Built-in programmable soft-start circuit suppresses inrush current during power-up startup.

Comprehensive protection mechanisms are embedded, including thermal shutdown, overcurrent protection, output short-circuit protection and power-good monitoring function. All control pins are ground-referenced, requiring no extra level shifting circuits for simple digital logic control.

Packaged in 28-pin thermally enhanced TSSOP surface mount housing with central exposed pad. The exposed thermal pad greatly improves heat dissipation performance during full-load continuous operation and restrains internal junction temperature rise. Moisture Sensitivity Level is MSL3; all reflow soldering procedures must be completed within 168 hours once the original vacuum package is opened. Tube delivery mode is adopted to facilitate manual breadboard debugging and small-volume equipment trial production.

The operating junction temperature range covers -40 °C to +125 °C, ensuring stable operation in industrial automation equipment, automotive electronic systems, laboratory test instruments and telecommunication power modules exposed to severe temperature fluctuations. Manufactured with lead-free construction, the component complies with global RoHS environmental directives. Full integration of power switches simplifies peripheral circuit layout, reduces overall component count and shortens power supply development cycle.

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