Monolithic Power Systems Inc. MP44011HS-LF-Z

Overview

MP44011HS-LF-Z from Monolithic Power Systems is a boundary-conduction-mode (BCM) active power-factor correction (PFC) controller with integrated harmonic injection, designed for pre-regulation in AC/DC converters. It delivers precise output voltage regulation via internal 2.5V reference and error amplifier, supports 13.4–22V supply operation, features ultra-low 40µA start-up current and 0.65mA quiescent current, and targets LED lighting drivers with two-stage architectures.

For engineers reviewing the MP44011HS-LF-Z datasheet, MP44011HS-LF-Z pinout, MP44011HS-LF-Z application, or MP44011HS-LF-Z equivalent, key selection criteria include harmonic-injection capability for bus capacitance reduction, ZCS-triggered MOSFET turn-on timing, adjustable over-voltage protection thresholds, and SOIC-8 package compatibility with high-density LED driver layouts.

Technical Context

The MP44011HS-LF-Z implements boundary-conduction-mode control using zero-current sensing (ZCS) on pin 5 to trigger MOSFET turn-on at inductor current zero-crossing, with internal 2.1V rising and 1.35V falling thresholds. Its harmonic injection function modifies the multiplier output (pin 3) by injecting constant-ratio harmonics into the rectified AC line signal, generating a "choppy sinusoidal" current reference that reduces peak primary current in flyback PFC topologies.

This architecture enables reduced transformer core size and lower bus capacitor requirements-verified in 30W LED driver designs with 70V_bus and 350mA output-while maintaining >0.9 PF. The device integrates on-chip current-sense filtering (pin 4), gate-driver clamping (15V max on pin 7), and dual OVP (static threshold 2.2V on COMP, dynamic detection at 40µA).

Key Specifications

Pinout & Package

MP44011HS-LF-Z is housed in an industry-standard 8-pin SOIC package (JEDEC MS-012, variation AA), with 1.27mm lead pitch and 3.9mm × 4.9mm body dimensions. Thermal resistance θ_JA = 90°C/W enables reliable operation up to +125°C junction temperature.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar boundary-mode PFC controller applications.

Compared with MP44010HS-LF-Z, MP44011HS-LF-Z delivers measurable reductions in bus capacitance and transformer size via harmonic injection; versus UCC28051DR, it offers simpler layout, lower component count, and inherent BCM timing-but lacks fixed-frequency EMI shaping.

Availability

MP44011HS-LF-Z is available at Aetrix Electronics and suitable for LED lighting drivers, two-stage AC/DC converters, flyback PFC pre-regulators, and high-efficiency boost PFC applications requiring stable component supply, RoHS compliance, and tape-and-reel packaging.

Supply support for MP44011HS-LF-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 analog and power ICs, with design centers in the US, China, and Taiwan, and global manufacturing partnerships.

The MP44011 belongs to MPS's Boundary-Mode PFC Controller product line, engineered specifically to simplify active power-factor correction in space-constrained, cost-sensitive LED lighting and general-purpose AC/DC power supplies.

FAQ

What is the purpose of the harmonic injection function in MP44011HS-LF-Z?

The harmonic injection function modifies the multiplier output to generate a "choppy sinusoidal" current reference, reducing peak primary current in flyback PFC topologies. This enables smaller transformer cores and lower bus capacitance-verified in 30W LED driver designs where it cut capacitor size by 35% and allowed use of an EE25 instead of EE30 core.

How does the ZCS pin (Pin 5) control MOSFET turn-on timing?

Pin 5 senses the falling edge of voltage on the transformer's auxiliary winding. When ZCS voltage drops below 1.35V (with 2.1V/1.35V hysteresis), the internal comparator triggers MOSFET turn-on, ensuring true boundary-conduction-mode operation. A 175µs internal timer provides fallback turn-on during startup when no ZCS signal is present.

What are the absolute maximum ratings for VIN and the ZCS pin?

VIN has an absolute maximum rating of +23V; exceeding this risks permanent damage. The ZCS pin tolerates -50mA to +10mA current and features internal clamps at 7.8V (high) and 0.55V (low); applying voltage beyond these clamps may degrade long-term reliability even if within current limits.

Can MP44011HS-LF-Z be used in boost PFC topologies, or is it limited to flyback?

MP44011HS-LF-Z supports both boost and flyback PFC topologies. Its harmonic injection and ZCS-triggered timing are equally effective in boost configurations-application notes confirm successful 65W boost PFC designs achieving >0.95 PF and <15% THD with standard ETD29 cores and 22µF bus capacitors.

What is the role of the COMP pin in over-voltage protection?

The COMP pin serves dual OVP functions: static OVP activates when COMP voltage falls below 2.2V (indicating sustained overvoltage), while dynamic OVP triggers when COMP current exceeds 40µA (detecting rapid output voltage rise). Both conditions disable the gate driver and place the IC in idle state until recovery conditions are met.

How does the on-chip filter on the CS pin improve system robustness?

The integrated RC filter on the CS pin attenuates high-frequency switching noise and ringing from the current-sense resistor path. This prevents false triggering of the current-comparator turn-off threshold, eliminating erratic MOSFET switching-especially critical in high-dV/dt flyback designs where external noise coupling is common.

Is MP44011HS-LF-Z pin-compatible with MP44010HS-LF-Z?

Yes-MP44011HS-LF-Z is a functional superset of MP44010HS-LF-Z with identical pinout, electrical specifications, and SOIC-8 package. The only difference is the addition of harmonic injection logic; all other parameters-including UVLO thresholds, gate drive strength, and thermal characteristics-are identical.