Monolithic Power Systems Inc. MP174AGS-P

Overview

MP174AGS-P from Monolithic Power Systems is a 700V primary-side constant-voltage (CV) regulator with integrated MOSFET, supporting buck, buck-boost, boost, and flyback topologies in non-isolated off-line power supplies. It delivers up to 400mA output current in CCM, achieves <30mW no-load power consumption, and features green-mode operation with frequency foldback and peak-current compression for high light-load efficiency. It is used in standby power and home appliance auxiliary supplies.

For engineers reviewing the MP174AGS-P datasheet, MP174AGS-P pinout, MP174AGS-P application, or MP174AGS-P equivalent, key selection criteria include its 700V/13.5Ω integrated MOSFET, VCC UVLO thresholds (5.1–5.7V turn-on, 3.0–3.6V stop), 2.55V FB reference, thermal shutdown at 150°C, and SOIC-8 package compatibility with board-level EMI mitigation requirements.

Technical Context

The MP174AGS-P implements primary-side regulation using internal error amplifier sampling and ramp compensation to maintain stable CV output without optocoupler feedback. Its control loop uses fixed-frequency DCM/CCM hybrid operation with programmable minimum off-time (9.5–15μs) and maximum on-time (19–31μs), enabling precise output voltage regulation via external resistor divider.

Protection architecture integrates five independent fault monitors: OLP triggered by FB <1.7V for ≥220ms, SCP at 750–900mA peak current, OTP at 150°C with 30°C hysteresis, open-loop detection at FB <0.5V, and VCC UVLO/stop thresholds-all coordinated through an auto-restart state machine with blanking during soft-start and initial 512 cycles.

Key Specifications

Pinout & Package

MP174AGS-P is housed in an industry-standard SOIC-8 package with exposed pad for enhanced thermal dissipation. Pin 1 is VCC, Pin 2 is FB, Pins 3 and 4 are SOURCE (internally tied), Pin 5 and Pin 6 are N/C, Pin 7 is DRAIN, and Pin 8 is N/C. The package supports standard reflow profiles and meets JEDEC MS-012 specifications.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP174AGS-P, MP174AGJ-Z trades thermal performance for miniaturization, while MP173AGS-Z sacrifices voltage rating, output capability, and green-mode features for cost reduction-making MP174AGS-P optimal for universal-input, high-efficiency, thermally demanding applications.

Availability

MP174AGS-P is available at Aetrix Electronics and suitable for home appliance auxiliary supplies, industrial sensor node power, and smart plug standby power requiring stable component supply, RoHS-compliant sourcing, and long-term production continuity.

Supply support for MP174AGS-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 analog and power ICs, with design centers in the US, China, and Taiwan, and global manufacturing partnerships.

The MP174A product line delivers primary-side regulated off-line controllers targeting cost-sensitive, space-constrained, and energy-efficient non-isolated AC/DC conversion in white goods, consumer electronics, and industrial controls.

FAQ

What is the maximum recommended output power for MP174AGS-P in continuous conduction mode?

The MP174AGS-P supports up to 5W output power in CCM, verified at 12V/400mA with proper inductor selection (≥0.36mH for 12V/0.3A), thermal management, and input capacitor sizing per MPS Application Note AN-107. Exceeding this limit risks OLP activation or thermal shutdown.

Can MP174AGS-P operate without an external VCC capacitor?

No. An external VCC capacitor (typically 1–10μF ceramic) is mandatory to stabilize the internal bias supply. The IC draws ~720μA during switching and relies on this capacitor to maintain VCC between 5.1–5.7V; omission causes erratic startup, UVLO cycling, or failure to initiate regulation.

How does the MP174AGS-P achieve <30mW no-load consumption?

It combines green-mode operation-reducing both switching frequency and peak current under light load-with internally biased VCC, low ICC (200μA no-switching), and frequency foldback. These features collectively minimize quiescent losses, enabling compliance with stringent global standby power regulations.

What is the purpose of the 350ns leading-edge blanking (LEB) time?

The 350ns LEB disables the current comparator immediately after MOSFET turn-on to suppress false triggering from parasitic turn-on spikes caused by diode reverse recovery and layout inductance. This prevents premature switch-off and ensures reliable current sensing during the stable portion of the switching cycle.

Is MP174AGS-P suitable for flyback topology with isolation?

Yes-though optimized for non-isolated topologies, the MP174AGS-P supports isolated flyback configurations using an auxiliary winding for feedback. However, isolation requires careful transformer design, Y-capacitor placement, and creepage/clearance validation per IEC 60950-1 or IEC 62368-1, as the IC itself provides only primary-side regulation.

What is the minimum off-time limit and how does it affect output power?

The minimum off-time is 9.5–15μs (typical 12μs), directly limiting maximum output power in CCM. Shorter τMin_off increases switching frequency and reduces available energy transfer per cycle; selecting too small an inductor can cause OLP at full load due to insufficient off-time for energy reset.

Does MP174AGS-P require external compensation components on the FB pin?

Yes-a feedback capacitor (C_FB) is required between FB and SOURCE to implement sample-and-hold functionality for accurate output voltage sensing. MPS recommends 100–470pF depending on output voltage and load transient response; omitting it degrades regulation accuracy and light-load stability.