Monolithic Power Systems Inc. MPQ4590GS-AEC1-Z

Overview

MPQ4590GS-AEC1-Z from Monolithic Power Systems is a 640V primary-side constant-voltage regulator IC with integrated 640V/13.5Ω MOSFET, supporting buck/buck-boost/boost/flyback topologies and delivering up to 400mA output current in CCM mode. It operates without optocoupler feedback, achieves <30mW no-load power consumption, and is AEC-Q100 qualified for automotive-grade reliability in PTC heater and standby power systems.

For engineers reviewing the MPQ4590GS-AEC1-Z datasheet, MPQ4590GS-AEC1-Z pinout, MPQ4590GS-AEC1-Z application, or MPQ4590GS-AEC1-Z equivalent, key selection criteria include primary-side CV regulation accuracy (2.55V FB reference), 640V drain breakdown voltage, SOIC-8 thermal resistance (θJA = 96°C/W), green-mode frequency foldback, and integrated OLP/SCP/OTP protection.

Technical Context

The MPQ4590GS-AEC1-Z implements primary-side constant-voltage regulation via sampling capacitor-based output sensing and internal error amplifier with 6µs post-MOSFET-turn-off sampling window. Its green-mode operation dynamically reduces switching frequency and peak current limit (660mA typ → down to ~480mA at -40°C) under light load to maintain high efficiency.

Protection architecture includes auto-restart OLP (220ms delay at 28kHz), SCP (900mA threshold), OTP (150°C shutdown / 120°C recovery), open-loop detection (<0.5V FB), and UVLO (5.3V turn-on / 5.6V turn-off hysteresis). The integrated 640V MOSFET enables direct high-voltage input handling in non-isolated topologies.

Key Specifications

Pinout & Package

MPQ4590GS-AEC1-Z is housed in a standard SOIC-8 package with exposed drain pad for thermal management. Pin 7 (DRAIN) connects directly to the internal 640V MOSFET drain and serves as high-voltage current source input; Pin 4 (SOURCE) is the MOSFET source and ground reference for VCC and FB; Pins 3,5,6,8 are NC and must remain unconnected.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MPQ4590GS-AEC1-Z, MPQ4570GS-AEC1-Z trades 140V headroom and 100mA output for lower R_DS(on) drift over temperature, while UCC28740DR offers superior CV accuracy at the expense of isolation requirement and external FET design overhead.

Availability

MPQ4590GS-AEC1-Z is available at Aetrix Electronics and suitable for automotive PTC heater control, electric/hybrid vehicle standby power, and industrial motor drive auxiliary supply requiring stable component supply with AEC-Q100 compliance and long-term lifecycle support.

Supply support for MPQ4590GS-AEC1-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 expertise in integrated power stages, DC/DC converters, and motor drivers.

The MPQ4590 product line delivers AEC-Q100-qualified primary-side regulators targeting non-isolated, high-voltage DC-DC conversion in automotive thermal management and industrial power systems where optocoupler-free design and ultra-low standby power are critical.

FAQ

What topologies does MPQ4590GS-AEC1-Z support?

The MPQ4590GS-AEC1-Z supports buck, buck-boost, boost, and flyback topologies. Its primary-side regulation architecture eliminates the need for optocouplers in non-isolated configurations (buck/buck-boost/boost) and enables simplified isolated flyback designs using indirect feedback. Each topology leverages the integrated 640V MOSFET and internal current sense for minimal external component count.

How does the MPQ4590GS-AEC1-Z achieve <30mW no-load power consumption?

It achieves <30mW no-load consumption through green-mode operation: switching frequency folds back and peak current limit compresses as load decreases, reducing dynamic losses. Combined with low VCC operating current (200μA in no-switching mode) and internally biased VCC, this minimizes quiescent power without requiring external bias windings or auxiliary supplies.

What is the function of the NC pins (3,5,6,8) on the SOIC-8 package?

Pins 3, 5, 6, and 8 are no-connect (NC) terminals - they are not bonded to the die and serve no electrical function. These pins must remain unconnected in PCB layout and schematic design. Leaving them floating avoids unintended coupling; soldering or routing to ground or other nets may cause malfunction or violate thermal derating assumptions.

Can MPQ4590GS-AEC1-Z be used in isolated flyback designs?

Yes, it supports isolated flyback topologies using indirect feedback via an auxiliary winding. The IC regulates output voltage by sampling the auxiliary winding voltage proportional to the output, eliminating the need for optocouplers. Design requires careful turns ratio selection and compensation for winding leakage inductance to maintain ±5% regulation across line/load/temperature.

What is the significance of the 640V drain rating in practical applications?

The 640V drain rating allows direct connection to rectified 400VAC mains (≈565V_PK) or 600V_DC battery buses with sufficient margin for voltage spikes and ringing. This eliminates external HV MOSFETs in automotive PTC heaters and industrial controls, simplifying design, improving reliability, and reducing EMI from external switching nodes.

How does the OLP protection mechanism work in MPQ4590GS-AEC1-Z?

OLP triggers when FB voltage drops below 1.7V (typical), indicating excessive load current. A 220ms timer starts counting at 28kHz switching frequency; if the condition persists, the IC enters latch-off mode, discharging VCC to 2.4V before attempting auto-restart. This delay prevents false triggering during startup transients while ensuring reliable shutdown under sustained overload.