Monolithic Power Systems Inc. MP6545AGF-Z

Overview

MP6545AGF-Z from Monolithic Power Systems is a three-phase half-bridge power stage IC designed for brushless DC motor drive applications. It integrates six N-channel MOSFETs (three independent half-bridges), operates from 4.5V to 45V input, delivers up to 2.5A per phase, and supports external shunt-based current measurement via dedicated LSSx pins. Used in laser printers and textile machines where compact, integrated motor drive with fault reporting is required.

For engineers reviewing the MP6545AGF-Z datasheet, MP6545AGF-Z pinout, MP6545AGF-Z application, or MP6545AGF-Z equivalent, this page provides verified technical context, validated pin functions, confirmed thermal and protection thresholds, and real-world implementation constraints including charge pump capacitor requirements and sleep-mode timing.

Technical Context

The MP6545AGF-Z implements independent high-side and low-side gate drivers per phase, each with internal pull-down resistors and logic-level inputs (VIH = 2V, VIL = 0.8V). It features automatic synchronous rectification triggered by OUTx voltage excursions beyond VIN or GND, reducing body-diode conduction losses during inductive recirculation.

Protection architecture includes latchable over-current detection (IOCP1/IOCP2 = 3–4.5A, tOCP = 1µs), input OVP (VOVP = 45–48V) and UVLO (VUVLO = 4.5V, hysteresis = 300mV), plus thermal shutdown at TJ = 165°C (hysteresis = 15°C). Fault status is reported via open-drain nFAULT with external pull-up requirement.

Key Specifications

Pinout & Package

MP6545AGF-Z uses the TSSOP-28EP package (9.6mm × 4.4mm, 0.65mm pitch) with exposed thermal pad. Pin numbering follows JEDEC MO-153 variation AET; pin 1 is marked by notch or dot. All logic inputs include internal 100kΩ pull-down resistors.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar three-phase half-bridge power stage applications.

Compared with MP6545AGF-Z, MP6550AGF-Z offers scalable headroom for future power increases without redesign, while DRV8313PWPR trades discrete current sensing simplicity for integrated analog sensing-requiring careful PCB layout but enabling faster current-loop bandwidth.

Availability

MP6545AGF-Z is available at Aetrix Electronics and suitable for laser printer motor drives, textile machine spindle controls, small-form-factor HVAC fans, and industrial vacuum pump controllers requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.

Supply support for MP6545AGF-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 global manufacturing partnerships.

The MP6545A product line targets cost-sensitive, space-constrained BLDC motor applications requiring integrated power stages with diagnostic capability-designed to replace discrete MOSFET + gate driver solutions in industrial and office automation.

FAQ

What is the minimum recommended PCB copper area for thermal management of MP6545AGF-Z?

For continuous 2.5A per phase operation at TA = 85°C, MPS recommends ≥400mm² of 2oz copper connected to the exposed thermal pad via ≥9 thermal vias (0.3mm diameter, filled or capped). Layout Figure 4 in the datasheet shows optimized copper pour placement adjacent to all VIN, GND, and OUT pins to minimize thermal resistance (θJA = 32°C/W).

Can MP6545AGF-Z operate with 100% duty cycle on high-side FETs?

Yes. The integrated charge pump (VCP = VIN + 5V) eliminates bootstrap capacitor limitations, enabling indefinite high-side FET conduction without voltage droop. This is confirmed in the Functional Block Diagram and Operation section, which specifies VCP generation independent of OUTx switching state.

How does the automatic synchronous rectification function respond to reverse EMF during motor deceleration?

When OUTx voltage falls below GND (e.g., due to inductive kickback), the LS-FET turns on until recirculation current approaches zero or an HS-FET command is received. This is explicitly defined in the Operation section and validated in Typical Performance Characteristic waveforms (pages 10–11) showing controlled current decay during power ramping down.

Is the nFAULT pin compatible with 3.3V microcontrollers?

Yes. nFAULT is an open-drain output with VOL ≤ 0.5V at 5mA sink current. A 10kΩ pull-up to 3.3V yields sufficient noise margin (VIH = 2V min), and the pin's leakage current (IOH ≤ 1µA) ensures negligible voltage drop-verified in Electrical Characteristics Table (page 5).

What is the maximum allowable dead time between HSx and LSx transitions?

The device enforces a fixed 80ns dead time between HSx turn-off and LSx turn-on (and vice versa) to prevent shoot-through. This value is specified in Typical Timing Characteristics (page 6) and is hardware-implemented-no external configuration is required or possible.

Does MP6545AGF-Z support PWM frequencies above 20kHz?

Yes. The datasheet confirms operation up to 100kHz in Application Information (page 15), with timing parameters (t1–t4 = 40–360ns, t5 = 1ns, t6 = 165ns) supporting clean switching at 50kHz. Thermal limits-not timing-govern maximum usable frequency in practice.

Are the LSSx pins internally connected to GND or isolated?

LSSx pins are electrically isolated low-side source terminals-not tied to internal GND. Each connects directly to the source of its respective LS-FET, enabling true Kelvin sensing when paired with external shunts. This is confirmed in the PIN FUNCTIONS table (page 3) and Typical Application Circuit (page 16).