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LS78ST1xx -- Drop-in replacement for PT78ST1xx

Drop in replacement for PT78ST1xx
High Efficiency, +5, +12, or _15VDC, 2Amp, Step-Down Converter / Switching Regulators

LSI Controls, Inc., introduces its small footprint, high efficiency, Integrated Switching Regulators. With a 33% greater current rating (2A continuous / 3A peak), the LS78ST1xx regulators are higher power pin compatible drop-in replacements for the now obsolete TI/Power Trends PT78ST1xx. The LS78ST1xx follows the same pinout and footprint as the PT78ST1xx. The installed surface mount height of the LSI equivalent is only 0.17” taller to deliver additional current capacity. It can be configured as a thru Hole (Horizontal or Vertical) or Surface mount device.

The regulator module boasts a high-output-current PWM converter that integrates a low resistance, high side N-Channel MOSFET and offers a wide input voltage range of +5.5 to 36VDC. The LS78ST1xx regulators run cool with conversion efficiencies up to 95%, and provides built-in current limiting, over voltage protection, and thermal shutdown safety features. Operating range is -40⁰C to 80⁰C with storage from -40⁰C to 125⁰C. The device also features a high performance voltage amplifier that provides tight voltage regulation accuracy under transient conditions, as well as an under voltage lockout feature that prevents startup until the input voltage reaches the minimum supply level. It also incorporates a slow-start circuit to limit inrush currents and a voltage feed forward circuit to improve transient response.

The LS78ST1xx is available for delivery with short lead-times in both thru-hole and surface mount configurations as part of LSI Control’s AcuWatt™ product line. Pricing for either option starts at $23.85 each with a 20 piece minimum quantity. Call for higher volume discounts.

Summary of Features: LS78ST1xx

  • Pin compatible drop in replacement for the TI or Power Trends PN: PT78ST105S
  • Wide Input Voltage Range: + 8 / 15 / 18 VDC to 36 VDC
  • High Conversion Efficiency up to 95%
  • Current Rating: 2 Amps Continuous, (3 Amp Peak) Output Current
  • Full Overcurrent limiting, over voltage and thermal shutdown protection
  • Can be configured as a Thru Hole (TH or TV) or as a Surface Mount (S) Device
  • Operating temperature: -40°C to 80°C
  • Storage temperature: -40°C to 125°C
  • Footprint: 800 mil x 1100 mil (20.3 x 28 mm)
  • Height: 490 mil (12.4mm)

LSI Controls, Inc. ( has provided comprehensive design and manufacturing services of high density electronic systems and components for both OEM and aftermarket upgrade applications since 1979.