Monolithic Power Systems Inc. MP175LGS-P

Overview

MP175LGS-P from Monolithic Power Systems is a 700V primary-side constant-voltage (CV) offline regulator with integrated 700V/4.5Ω MOSFET, supporting buck/buck-boost/boost/flyback topologies, delivering up to 600mA output current and featuring brown-in protection, <30mW no-load power consumption, and SOIC-8 packaging - deployed in home appliance standby supplies and low-power industrial controls.

For engineers reviewing the MP175LGS-P datasheet, MP175LGS-P pinout, MP175LGS-P application, or MP175LGS-P equivalent, this page delivers verified technical context, topology-specific design meaning for key parameters, validated pin functions, real-world application cards, and two confirmed alternative parts with documented functional and application-level differences.

Technical Context

The MP175LGS-P implements primary-side CV regulation without optocoupler feedback, using FB pin voltage (2.43V typ) to control MOSFET on-time via internal peak-current limiting (1.1A typ) and minimum off-time (24μs typ). Its green-mode operation dynamically reduces switching frequency and peak current under light load to maintain efficiency.

It integrates a 700V high-voltage current source for VCC startup, brown-in detection at 40V (VDS_BI), and protection logic including OTP (150°C), SCP (155% ILIMIT), OLP (4096-cycle counter), and open-loop detection (0.3V VOLD). All protections trigger hiccup-mode recovery except OTP, which holds shutdown until junction cools.

Key Specifications

Pinout & Package

MP175LGS-P is housed in a standard SOIC-8 package (JEDEC MS-012, variation AA) with exposed DRAIN pads for thermal relief and creepage-compliant pin spacing. The 8-pin layout supports primary-side regulation with dedicated GNDA/GNDP separation for noise immunity.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar primary-side offline regulator applications.

Compared with MP175LGS-P, MP174GSG-P sacrifices brown-in and voltage margin for lower R_ON, while LNK3206P demands more external components and delivers inferior light-load performance - making MP175LGS-P optimal for new universal-input, low-standby, high-reliability designs.

Availability

MP175LGS-P is available at Aetrix Electronics and suitable for home appliance standby power, industrial sensor node biasing, and commercial lighting auxiliary supplies requiring stable component supply, long-lifecycle support, and RoHS-compliant sourcing.

Supply support for MP175LGS-P includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Monolithic Power Systems (MPS) is a fabless semiconductor company specializing in high-performance power management ICs, with over 20 years of expertise in DC/DC converters, AC/DC controllers, and motor drivers.

The MP175L product line targets cost-sensitive, non-isolated offline power conversion in white goods and industrial controls, emphasizing integration, low no-load loss, and robust protection for unattended operation.

FAQ

What topologies does MP175LGS-P support, and how is configuration achieved?

The MP175LGS-P supports buck, buck-boost, boost, and flyback topologies through external component selection - not internal configuration. Inductor placement, diode orientation, and transformer turns ratio determine topology; the IC's primary-side CV control adapts automatically without mode pins or programming.

How does brown-in protection function, and what is its practical impact on system behavior?

Brown-in protection samples DRAIN-to-GND voltage and prevents restart until V_DS exceeds 40V after shutdown. This avoids repeated failed start attempts during marginal line conditions, reducing thermal stress and audible noise - critical for appliances where users expect silent, reliable standby operation.

Can MP175LGS-P operate without an external VCC capacitor, and what is the minimum recommended value?

No - an external VCC capacitor is mandatory for stable operation. MPS specifies a minimum of 1μF ceramic (X7R) placed near Pin 1. A 4.7μF/25V electrolytic is typical; undersizing causes VCC droop during peak load, triggering UVLO and intermittent shutdown.

What is the role of GNDA and GNDP separation, and what happens if they are not shorted externally?

GNDA (Pin 3) is the analog ground reference for FB and internal comparators; GNDP (Pin 4) is the power ground return. They must be shorted externally with a low-inductance trace. Failure to do so introduces noise into FB sensing, causing output voltage instability and premature OLD triggering.

How does the soft-start sequence affect overload protection timing during initial power-up?

The 8-step soft-start (SS) disables OLP, SCP, and OLD for its duration (~10ms). This prevents false OLP triggering during inrush, as the counter only begins counting after SS completes. Designers must size input capacitance to ensure VCC remains above VCCL throughout SS to avoid reset loops.

Is MP175LGS-P qualified for use in safety-certified end equipment, and what certifications apply?

MP175LGS-P itself is not safety-certified, but it is designed to meet requirements for end-equipment certification (UL/IEC 62368-1, EN 61000-3-2). Its 700V DRAIN rating, reinforced creepage in SOIC-8, and comprehensive protection suite enable certified designs when used per MPS AN-107 layout and transformer guidelines.

What is the maximum achievable output power, and what limits it in practice?

Maximum continuous output power is 9W (e.g., 12V/750mA), limited by thermal dissipation in SOIC-8 (1.64W P_D max at 25°C ambient) and the 600mA CCM current limit. At full load, board-level thermal design - especially DRAIN copper area - determines actual deliverable power before OTP activation.