Monolithic Power Systems Inc. MP44018-AGS-P

Overview

MP44018-AGS-P from Monolithic Power Systems is a CrM/DCM multi-mode active PFC controller in SOIC-8 package, designed for high-efficiency AC/DC front-end stages. It delivers valley-switching control, <30mW no-load power, 2.5V reference voltage with ±0.037V tolerance, and integrated brown-in/brownout detection at 1.0V/0.9V thresholds-enabling compliance with IEC 61000-3-2 Class C in LCD TVs and open-frame SMPS.

For engineers reviewing the MP44018-AGS-P datasheet, MP44018-AGS-P pinout, MP44018-AGS-P application, or MP44018-AGS-P equivalent, key selection criteria include light-load efficiency via dead-time extension, THD improvement through variable-on-time DCM control, OCP/OCL thresholds (0.5V/0.75V), burst-mode soft-on/off sequencing, and mains feed-forward compensation for dynamic line regulation.

Technical Context

The MP44018-AGS-P implements dual-mode operation: critical conduction mode (CrM) at full load for low THD, transitioning seamlessly to discontinuous conduction mode (DCM) under light load using COMP-voltage–driven dead-time extension (tDEAD_MAX = 23µs). Its nonlinear transconductance amplifier (GM1–GM3: 80–940 µS) enables enhanced dynamic response during load transients by scaling gain up to 8× on 4% output deviation.

Valley switching is enforced via zero-current detection (ZCD) with 0.3µs leading-edge blanking, 0.75V/0.25V hysteresis thresholds, and 150ns turn-on delay. Protection logic includes cycle-by-cycle OCL (500mV), latched OCP (750mV, 80ms auto-recovery), FB-based UVP (0.4V) and OVP (2.7V), and thermal shutdown at 150°C with 40°C hysteresis.

Key Specifications

Pinout & Package

MP44018-AGS-P is housed in an industry-standard SOIC-8 package (4.9mm × 3.9mm, 1.27mm pitch), optimized for surface-mount assembly and thermal dissipation in compact PFC boost stages.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar CrM/DCM PFC controller applications.

Compared with UCC28056DR and FAN6300MX, MP44018-AGS-P uniquely combines CrM/DCM dual-mode operation, valley switching, and burst-mode soft sequencing-delivering superior THD, lower standby power, and broader line/load adaptability in single-chip PFC solutions.

Availability

MP44018-AGS-P is available at Aetrix Electronics and suitable for LCD/OLED TVs, desktop PC power supplies, and industrial open-frame SMPS requiring stable component supply, long-term lifecycle support, and RoHS-compliant manufacturing.

Supply support for MP44018-AGS-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 design centers in the US, China, and Taiwan.

The MP44018A product line targets high-efficiency, low-standby-power active PFC applications in consumer and industrial AC/DC converters-emphasizing integration, thermal robustness, and regulatory compliance.

FAQ

What is the maximum recommended junction temperature for continuous operation?

The MP44018-AGS-P is rated for continuous operation up to 125°C junction temperature. Its thermal shutdown activates at 150°C with 40°C hysteresis, and the SOIC-8 package has θJA = 90°C/W on a 4-layer PCB. Derating is required above 100°C ambient to maintain TJ ≤ 125°C under full load.

How does the device achieve THD improvement in DCM mode?

Unlike conventional constant-on-time controllers, MP44018-AGS-P uses variable-on-time control in DCM-where tON scales with mains voltage and COMP level. This maintains near-resistive input impedance across the AC cycle, reducing 3rd and 5th harmonic content and ensuring IEC 61000-3-2 Class C compliance even at 20% load.

Can the ZCD pin be used with a resistive divider instead of an auxiliary winding?

No-the ZCD pin requires a clean, low-impedance signal derived from an auxiliary winding on the boost inductor. A resistive divider from the main switch node introduces excessive ringing and false zero-crossing detection due to lack of phase alignment and insufficient slew rate, violating the 0.3µs blanking requirement.

What is the purpose of the nonlinear GM amplifier, and how is it configured?

The nonlinear GM amplifier dynamically adjusts transconductance (80–940 µS) based on FB voltage deviation from 2.5V. At ±4% deviation, gain increases 4× or 8× to accelerate COMP response-reducing output undershoot/overshoot during load steps without external compensation changes.

Does the device support automatic restart after over-temperature shutdown?

Yes-after OTP triggers at 150°C, the device halts switching and holds COMP low. Once junction temperature falls below 110°C (150°C – 40°C hysteresis), UVLO resets and normal operation resumes automatically without external intervention or power cycle.

How is mains feed-forward compensation implemented using the MAINSIN pin?

MAINSIN voltage (scaled AC peak) modulates the slope of the internal COMP ramp generator. As line voltage rises, ramp slope increases proportionally-shortening on-time to maintain constant power and improve line regulation. This reduces output voltage variation from 85VAC to 265VAC to ±0.5% without additional feedback components.

What is the minimum recommended value for the ZCD pull-up resistor?

The ZCD pin requires a pull-up resistor (RZCD) sized to ensure ≥0.75V at peak auxiliary voltage while limiting current to <3mA. For a 265VAC input and 1:10 auxiliary ratio, RZCD ≥ 2.2kΩ is typical. Values below 1.5kΩ risk excessive current and thermal drift; values above 10kΩ increase noise susceptibility.