Monolithic Power Systems Inc. MP6545GF-P

Overview

MP6545GF-P 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 high-side and three low-side), operates from 4.5V to 45V input, delivers up to 2.5A per phase, features 150mΩ typical R_DS(ON) per FET, and includes OCP, OVP, UVLO, and thermal shutdown. It is used in compact BLDC motor control stages where space-constrained PCB layout and integrated protection are critical.

For engineers reviewing the MP6545GF-P datasheet, MP6545GF-P pinout, MP6545GF-P application, or MP6545GF-P equivalent, this page provides verified technical context, validated pin functions, confirmed package mapping to TSSOP-28EP, real-world timing characteristics (e.g., 40–360ns gate delays), and alternative selection guidance based on functional equivalence in three-phase motor driver stages.

Technical Context

The MP6545GF-P implements independent three-channel half-bridge drivers with separate HSx/LSx logic inputs per phase, enabling direct microcontroller PWM control without external gate drivers. Its internal charge pump (VCP) generates >VIN+5V for high-side gate drive, while VREG supplies 5V for low-side logic and gate circuitry.

It supports automatic synchronous rectification: when both HS and LS FETs are off and OUTx voltage drops below GND or rises above VIN, the corresponding LS or HS FET turns on to recirculate inductive current-reducing body-diode conduction loss. Fault reporting is handled via open-drain nFAULT with active-low latched indication for OCP, OVP, and thermal events.

Key Specifications

Pinout & Package

MP6545GF-P is packaged in TSSOP-28EP (9.7mm × 4.4mm × 1.2mm), featuring an exposed thermal pad for enhanced heat dissipation. The package complies with JEDEC MO-153, Variation AET, and has MSL Level 2a moisture sensitivity.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MP6545GF-P, MP6550GF-Z offers higher current headroom at the cost of increased thermal demand, while DRV8313PWPR trades analog simplicity for digital control flexibility and added sensing-but increases component count and firmware complexity.

Availability

MP6545GF-P is available at Aetrix Electronics and suitable for brushless DC motor control, industrial fan regulation, and automated office equipment requiring stable component supply across extended production lifecycles.

Supply support for MP6545GF-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, and global manufacturing partnerships.

The MP6545 belongs to MPS's Simple Three-Phase Power Stage product line, engineered to replace discrete MOSFET + gate driver solutions in space- and cost-sensitive BLDC motor applications-emphasizing integration, protection, and ease of layout.

FAQ

What is the maximum recommended PCB copper area and thermal via count for MP6545GF-P at 2.5A continuous per phase?

The datasheet specifies 3.9W maximum power dissipation at 25°C ambient for the TSSOP-28EP package. To sustain 2.5A per phase continuously, use ≥2oz copper on top/bottom layers, a 12mm² exposed thermal pad soldered to internal ground planes, and at least eight 0.3mm-diameter thermal vias (filled or plated) connecting the pad to inner-layer ground planes. This achieves θ_JA ≈32°C/W and keeps junction temperature below 125°C at 60°C ambient.

Can MP6545GF-P operate with a 3.3V microcontroller directly driving HSx/LSx pins?

Yes. The HSx and LSx inputs have CMOS-compatible thresholds (VIH = 2V min, VIL = 0.8V max) and internal 100kΩ pull-down resistors. A 3.3V MCU GPIO meets these levels without level-shifting. However, ensure trace lengths are short (<10mm) and routed away from noisy power paths to prevent false triggering due to coupling.

How does the automatic synchronous rectification function interact with external freewheeling diodes?

MP6545GF-P's automatic synchronous rectification actively turns on the appropriate LS or HS FET during inductive flyback-making external diodes unnecessary and potentially harmful. Adding external diodes can cause shoot-through or reverse-bias stress on the internal FETs. The IC's body diodes are only used if synchronous rectification is disabled (not supported) or during sub-100ns transitions before gate drive activation.

Is the nFAULT pin latched or auto-recovering after an over-current event?

nFAULT is latched low after OCP, OVP, or thermal shutdown. It remains asserted until the fault condition clears *and* the device is reset-either by pulling nRESET low for >100ns or by cycling VIN. Simply removing the overload does not restore operation; explicit reset is required to re-enable gate drive outputs and clear the fault latch.

What is the minimum required external capacitor on the VCP pin, and why must it be connected to VIN instead of GND?

A minimum 1µF, 16V X7R ceramic capacitor is required between VCP and VIN. This capacitor stores charge to boost the high-side gate drive voltage above VIN (typically VIN + 5V), enabling full enhancement of the N-channel HS FETs. Connecting it to GND would disable the charge pump function and prevent HS FET turn-on, resulting in single-ended (LS-only) operation and motor stall.

Does MP6545GF-P support 100% duty cycle on any output channel?

No. Due to its charge pump architecture, MP6545GF-P cannot sustain 100% high-side duty cycle-the VCP capacitor discharges over time without periodic LS-FET conduction to refresh the pump. Maximum practical HS duty cycle is ~95% at 20kHz; for true 100% drive, an external bootstrap or isolated supply is required, which this IC does not provide.

How does the OCP threshold vary with temperature, and is external adjustment possible?

OCP threshold decreases slightly with rising temperature: HS-FET trip point drops from ~4.5A at −50°C to ~4.2A at +125°C; LS-FET follows similar drift. The threshold is fixed by internal current-sense amplifier gain and reference-no external resistor or pin adjusts it. For stable current limiting across temperature, design with worst-case (low-temp) threshold and verify margin at max operating temperature.