Monolithic Power Systems Inc. MP44018-AGS-Z

Overview

MP44018-AGS-Z 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, <30 mW no-load power consumption, 2.5 V reference voltage with ±1.5% tolerance, and integrated brown-in/brownout detection at 1.0 V / 0.9 V thresholds-enabling compliance with IEC 61000-3-2 Class C in LCD TVs and open-frame SMPS.

For engineers reviewing the MP44018-AGS-Z datasheet, MP44018-AGS-Z pinout, MP44018-AGS-Z application, or MP44018-AGS-Z equivalent, key selection criteria include light-load efficiency optimization via dead-time extension, THD improvement through variable-on-time DCM control, OVP/UVP thresholds with blanking timers, burst-mode soft-on/off sequencing, and mains feed-forward compensation for dynamic line regulation.

Technical Context

The MP44018-AGS-Z 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. Its valley-switching logic relies on ZCD pin detection with 0.3 µs leading-edge blanking and 150 ns turn-on delay after zero-current crossing.

It features nonlinear transconductance amplification (GM1 = 105 µS, GM2 = 280 µS, GM3 = 780 µS) for enhanced transient response, plus dedicated mains-sense feed-forward scaling to maintain constant power across 85–265 VAC input. Protection includes cycle-by-cycle OCL at 500 mV, latched OCP at 750 mV with 80 ms auto-recovery, and thermal shutdown at 150 °C.

Key Specifications

Pinout & Package

MP44018-AGS-Z is housed in an industry-standard SOIC-8 package with exposed pad (not thermally enhanced), rated for 1.4 W power dissipation at 25 °C ambient. Pin numbering follows JEDEC MS-012, with GND (Pin 6) placed adjacent to GATE (Pin 7) to minimize gate loop inductance.

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-Z uniquely combines CrM/DCM dual-mode operation, variable-on-time control for THD reduction, and mains-compensated feed-forward-making it the only option among the three that achieves both IEC 61000-3-2 Class C compliance and sub-30 mW no-load power in a single SOIC-8 device.

Availability

MP44018-AGS-Z is available at Aetrix Electronics and suitable for LCD/OLED TV power supplies, desktop/server front-ends, and open-frame AC/DC adapters requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for MP44018-AGS-Z 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, and manufacturing partners across Asia.

The MP44018A product line targets high-efficiency, low-standby-power active PFC solutions for consumer, computing, and industrial AC/DC power conversion-emphasizing integration, thermal robustness, and regulatory compliance without external complexity.

FAQ

What is the minimum recommended FB divider resistor value for MP44018-AGS-Z?

The datasheet recommends RO1 ≥ 10 MΩ to minimize standby power consumption. Using lower values increases quiescent current and degrades no-load efficiency. For 400 V output regulation, RO1 = 10 MΩ and RO2 ≈ 62.5 kΩ yields 2.5 V at FB, satisfying UVP/OVP thresholds and bias current limits.

How does the MP44018-AGS-Z achieve improved THD versus constant-on-time PFC controllers?

It uses variable-on-time control in DCM mode, where tON scales with mains voltage and load to maintain sinusoidal input current. This avoids the harmonic distortion inherent in fixed-on-time architectures, achieving <10% THD at 50% load per IEC 61000-3-2 Class C testing conditions.

Can MP44018-AGS-Z operate without an auxiliary winding for ZCD sensing?

No. The ZCD pin requires connection to an auxiliary winding on the boost inductor to detect valley conditions. Omitting it disables valley switching, forcing hard-switching operation and increasing MOSFET losses and EMI-invalidating the core efficiency and reliability claims.

What is the purpose of the 50 ms brownout timer, and how is it reset?

The timer confirms brownout when MAINSIN peak voltage remains below 0.9 V for 50 ms. It resets automatically upon detection of a brown-in event (MAINSIN > 1.0 V), triggering COMP soft-start and resuming PFC operation-ensuring clean recovery from deep sags without manual intervention.

Does MP44018-AGS-Z support external synchronization?

No. It operates autonomously with internal oscillator and valley-based timing. There is no SYNC pin or frequency-lock capability. Synchronization must be implemented externally using discrete logic if required for multi-phase systems, but this is not supported in the reference design.

How is the maximum dead time (23 µs) enforced during light-load operation?

Dead time is extended linearly as internal VCOMPI drops below 0.38 V. When VCOMPI reaches ~0 V, tDEAD_MAX = 23 µs is reached. This is hardware-controlled via analog circuitry-not software-configurable-and ensures consistent valley alignment even at near-zero load.

What failure modes trigger immediate shutdown versus auto-recovery?

OCP and OTP cause immediate shutdown with auto-recovery (80 ms OCP timer, thermal hysteresis). OVP, UVP, and brownout trigger latched shutdown until fault condition clears. ZCD/CS/FB open-circuit faults disable switching until power cycle or VCC reset.