700V Non-Isolated Off-Line Regulator, Up to 400mA Output Current with Improved EMI Performance

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Product Description

The MP174A is a primary-side regulator that provides accurate constant voltage (CV) regulation without an opto-coupler. It supports buck, buck-boost, boost, and flyback topologies. It has an integrated 700V MOSFET to simplify the structure and reduce costs. These features make it an ideal regulator for off-line low power applications, such as home appliances and standby power.

The MP174A is a green-mode‑operation regulator. Both the peak current and switching frequency decrease as the load decreases. This feature provides excellent efficiency at light load and improves the overall average efficiency.

The MP174A has various protection features, including thermal shutdown (OTP), VCC under-voltage lockout (UVLO), over-load protection (OLP), short-circuit protection (SCP), and open-loop detection.

The MP174A is available in a small TSOT23-5 package and SOIC8 package.

Product Features

  • Primary-Side CV Control, supporting Buck, Buck-Boost, Boost, and Flyback Topologies
  • Integrated 700V/13.5Ω MOSFET and Current Source
  • <30mW No-Load Power Consumption
  • Up to 5W Output Power
  • Maximum DCM Output Current Less than 250mA
  • Maximum CCM Output Current Less than 400mA
  • Low VCC Operating Current
  • Frequency Foldback
  • Limited Maximum Frequency
  • Peak-Current Compression
  • Internally Biased VCC
  • OTP, UVLO, OLP, SCP, Open-Loop Detection


  • Vac (max) (V)305
  • Vfb (V)2.55
  • Vbr (V)700
  • Rds(on) (Ω)13.5
  • fsw (max) (kHz)83
  • Isw Limit (mA)660
  • Iout (DCM) (max) (mA)250
  • Iout (CCM) (max) (mA)400
  • Pout (max) (W)5
  • Vac (min) (V)20
  • Power Range DefinedNo
  • Control MethodOn-Off
  • PackageSOIC-8, TSOT23-5
  • TypeBuck Regulator
  • No-Load Pout (max) (mW)30
  • Iregulator (mA)4.1
  • Ileak (µA)10
Quality Policy, Certificates & Reliability Reports
All MPS parts are lead-free, halogen-free and adhere to the RoHS directive. See Environmental section for details.