Monolithic Power Systems Inc. MP172AGS-P

Overview

MP172AGS-P from Monolithic Power Systems is a 700V primary-side offline regulator IC with integrated MOSFET, supporting buck/boost/buck-boost/flyback topologies for non-isolated AC/DC conversion. It delivers up to 120mA output current in CCM, achieves <30mW no-load consumption, and features green-mode operation with frequency foldback and peak current compression for high light-load efficiency - deployed in home appliance standby power supplies.

For engineers reviewing the MP172AGS-P datasheet, MP172AGS-P pinout, MP172AGS-P application, or MP172AGS-P equivalent, this page provides verified technical context, SOIC-8 package mapping, CV regulation behavior, protection thresholds (TSD @ 150°C, SCP @ 440mA typ), and topology-specific design meaning for rapid integration into low-power offline systems.

Technical Context

The MP172AGS-P implements primary-side constant voltage (CV) regulation using internal 2.55V reference feedback sampling via external resistor divider, eliminating optocoupler dependency. Its integrated 700V/20Ω MOSFET enables direct high-voltage switching, while leading-edge blanking (350ns) suppresses turn-on spike false triggering.

Green-mode operation dynamically reduces both switching frequency and peak current limit under decreasing load - achieving 3W max output power with 120mA CCM and 80mA DCM limits. Protection logic includes auto-restart OLP (175ms delay), latch-off SCP, thermal shutdown (150°C trip / 120°C recovery), and open-loop detection (VFB < 0.5V).

Key Specifications

Pinout & Package

MP172AGS-P is housed in an SOIC-8 package with exposed pad (non-thermal-pad variant per Rev. 1.0 datasheet), rated MSL Level 2, and optimized for surface-mount assembly in space-constrained consumer power stages.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP174AGS-Z, MP172AGS-P trades peak current headroom for tighter EMI control and lower system cost; versus LNK3206G, it delivers measurable efficiency gains below 20% load and eliminates need for external compensation components.

Availability

MP172AGS-P is available at Aetrix Electronics and suitable for home appliance control, industrial sensor node standby, and consumer electronics low-power adapter applications requiring stable component supply and long-lifecycle support.

Supply support for MP172AGS-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 MP172A product line targets cost-sensitive, non-isolated offline power conversion in white goods and consumer electronics, emphasizing integration, regulatory compliance, and ease of certification.

FAQ

What is the maximum continuous output power achievable with MP172AGS-P in SOIC-8 package?

The MP172AGS-P supports up to 3W continuous output power in CCM operation at 25°C ambient, limited by SOIC-8 thermal resistance (θ_JA = 96°C/W) and internal 120mA current limit. Derating is required above 60°C ambient; full 3W requires ≤40°C case temperature per datasheet Figure 1.

Can MP172AGS-P operate in flyback topology with transformer isolation?

Yes - MP172AGS-P supports isolated flyback configurations using an external transformer, with indirect feedback via auxiliary winding. The IC regulates based on reflected voltage timing, enabling safety-isolated outputs while retaining primary-side control advantages.

How does the MP172AGS-P achieve <30mW no-load consumption?

It combines green-mode frequency foldback, peak current compression, and ultra-low quiescent current (200µA in no-switching state). At no load, switching frequency drops below 10kHz and peak current falls to ~50mA, minimizing both conduction and switching losses in the integrated MOSFET.

What is the purpose of the dual SOURCE pins (pins 2 and 3) in SOIC-8 package?

Pins 2 and 3 are internally bonded to the same MOSFET source node to reduce parasitic inductance and improve current sharing during high di/dt switching events. This dual connection lowers effective source impedance by ~30%, enhancing stability in high-frequency flyback designs.

Does MP172AGS-P require an external startup resistor?

No - the device incorporates an internal high-voltage current source connected to the DRAIN pin, enabling self-starting from rectified AC line without external resistor. Startup occurs when DRAIN voltage exceeds 100V, drawing 4.1mA typical to charge the VCC capacitor.

What is the minimum recommended output capacitor value for stable regulation?

A minimum 47µF low-ESR electrolytic or ceramic capacitor is recommended at the output to ensure sufficient energy storage during minimum off-time intervals. Values below 22µF risk instability under light-load conditions due to insufficient hold-up for FB sampling.

How does open-loop detection function during start-up?

Open-loop detection is blanked for the first 512 switching cycles to prevent false triggering during initial capacitor charging. After blanking, it monitors FB voltage continuously; if VFB falls below 0.5V, the IC stops switching and initiates auto-restart after VCC discharges to 2.5V.