The LTC7138 from Linear Technology is a step-down DC/DC voltage regulator that can be powered from a remarkably wide input voltage range.  The regulator has good efficiency and draws just 12 µA while maintaining a regulated output voltage at no load. It can supply up to 400 mA and features a programmable peak current limit which helps optimize efficiency by reducing output ripple and external component size.

The LTC7138 includes a precise run threshold and soft-start feature to guarantee that the power system start-up is well-controlled. A feedback comparator output enables multiple LTC7138s to be connected in parallel for higher current applications. The output voltage can be configured by the logic state of two VPRG inputs to give a fixed output of 1.8, 3.3 or 5V or adjustable via a resistor divider network giving an output between 0.8 V and VIN.

Key features of the LTC7138:

  • Operating input voltage range: 4V to 140V
  • Internal low resistance power MOSFET
  • No compensation required
  • Adjustable 100mA to 400mA max output current
  • Low dropout operation: 100% duty cycle
  • Quiescent Current: 12 μA
  • Output range: 0.8V to VIN
  • 0.8V ±1% feedback voltage reference
  • Precise RUN pin threshold
  • Internal or external soft-start
  • Programmable 1.8 V, 3.3 V, 5 V or adjustable output
  • Programmable input overvoltage lockout
  • Thermally enhanced high voltage MSOP package

The LTC7138 is available in a thermally enhanced high voltage-capable 16-lead MSE package with four missing pins.