Monolithic Power Systems Inc. MP175GS

Overview

MP175GS from Monolithic Power Systems is a 700V primary-side constant-voltage (CV) offline regulator IC with integrated 700V/4.5Ω MOSFET, supporting buck, buck-boost, boost, and flyback topologies. It delivers up to 600mA output current in CCM, achieves <30mW no-load power consumption, and operates across -40°C to +125°C junction temperature for non-isolated AC/DC conversion in home appliances and standby power supplies.

For engineers reviewing the MP175GS datasheet, MP175GS pinout, MP175GS application, or MP175GS equivalent, this page provides verified technical context, SOIC-8 package mapping, CV regulation behavior under light-load foldback, OTP/SCP/OLP/BOP/OLD protection implementation, and real-world design trade-offs for fixed vs. adjustable output configurations.

Technical Context

The MP175GS implements primary-side CV regulation without optocoupler feedback by sensing VCC or FB voltage-enabling fixed-output operation when FB is unconnected (internal 500kΩ lower divider) or adjustable output via external resistor divider. Its green-mode operation dynamically reduces both peak current limit (1.1A typ.) and switching frequency under decreasing load to maintain >85% efficiency at 115–230VAC input.

Start-up relies on an internal 700V high-voltage current source charging the VCC capacitor; regulation begins when VCC reaches 8.4–9.6V (VHVoff), and HV supply re-engages if VCC drops below 7.9–9.1V (VHVon). Protection logic includes 8192-cycle OLP counter, 135–175% ILimit SCP threshold, 0.2–0.4V open-loop detection, and thermal shutdown at 150°C.

Key Specifications

Pinout & Package

MP175GS is housed in a standard SOIC-8 package with exposed thermal pad connection on DRAIN pins (5–8); GNDP (pin 4) and GNDA (pin 3) must be shorted externally per layout guidelines.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP175GS, MP174GS sacrifices surge margin and protection completeness for lower unit cost, while LNK3206G trades integration and light-load performance for compatibility with existing InnoSwitch-based layouts-neither matches MP175GS's combination of 700V rating, <30mW no-load, and six-layer protection stack.

Availability

MP175GS is available at Aetrix Electronics and suitable for home appliance auxiliary power, smart plug standby conversion, and industrial sensor node auxiliary supplies requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MP175GS 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 analog and power ICs, with focus on energy-efficient DC/DC and AC/DC solutions.

The MP175 product line targets cost-sensitive, non-isolated offline power conversion in consumer and white-goods applications-designed to replace discrete HV FET + controller combinations with single-chip integration and green-mode operation.

FAQ

What is the maximum output power achievable with MP175GS in continuous conduction mode?

The MP175GS supports up to 10W output power in CCM, determined by its 600mA maximum CCM output current, 700V drain rating, and thermal limits. Real-world output depends on inductor selection, PCB copper area for DRAIN thermal dissipation, and ambient temperature-designs exceeding 8W require careful attention to θ_JA derating per the 76°C/W SOIC-8 specification.

Can MP175GS operate without an external feedback resistor divider?

Yes-MP175GS supports fixed-output operation by using VCC as the feedback node when FB is left unconnected. An internal 500kΩ lower resistor forms a divider with the external output-to-VCC resistor, setting output voltage to ~17V. This configuration eliminates external FB components but disables open-loop detection (OLD) and requires stable VCC capacitor selection per application note AN-101.

How does the MP175GS implement brown-out protection (BOP)?

BOP triggers when the MOSFET turn-on time reaches t_MAXON (29.5–39.5μs) for four consecutive switching cycles-indicating insufficient input voltage to sustain regulation. This prevents erratic operation during deep AC sags. BOP recovery occurs automatically once input voltage rises sufficiently to reduce on-time below the threshold, without requiring power-cycle reset.

What is the purpose of the dual ground pins (GNDA and GNDP) on MP175GS?

GNDA (pin 3) serves as the analog reference for the FB comparator and internal error amplifier, while GNDP (pin 4) carries high di/dt return current from the internal MOSFET source. Shorting them externally minimizes ground shift between signal and power paths, preventing CV regulation instability caused by shared-impedance noise coupling into the FB node.

Does MP175GS require a minimum load to maintain regulation?

MP175GS does not require a minimum load for regulation, but a dummy load (typically 1–5mA) is recommended to absorb residual energy during no-load operation and prevent output voltage overshoot. Without it, light-load regulation degrades due to reduced switching frequency and increased output capacitor ESR effects-especially in fixed-output configurations relying on VCC feedback.

How is over-temperature protection (OTP) implemented in MP175GS?

OTP uses an on-die thermal sensor that monitors junction temperature continuously. When temperature exceeds 150°C (guaranteed), the IC halts switching and enters thermal shutdown. Recovery occurs only after junction temperature falls below the hysteresis threshold (~140°C), ensuring safe restart without manual intervention or external reset circuitry.

What layout practices are critical for MP175GS EMI performance?

Minimize the high-di/dt loop formed by C_IN, DRAIN pins (5–8), freewheeling diode, and output capacitor; place a 1nF bypass capacitor between FB and GND as close as possible to the IC; connect DRAIN pins to a large copper pour for thermal and EMI control; and separate AC input traces from FB and VCC routing to avoid capacitive coupling of line noise into regulation nodes.