Monolithic Power Systems Inc. MPM3864GPQ-Z

Overview

MPM3864GPQ-Z from Monolithic Power Systems is a fully integrated, synchronous step-down power module with internal inductor, delivering 6A continuous output current across 2.75V–7V input range. It features constant-on-time (COT) control, fixed 1.2MHz switching frequency, and integrated protection including OCP, SCP, UVLO, and thermal shutdown - deployed in FPGA core voltage regulation and optical module power supplies.

For engineers reviewing the MPM3864GPQ-Z datasheet, MPM3864GPQ-Z pinout, MPM3864GPQ-Z application, or MPM3864GPQ-Z equivalent, key selection criteria include its ECLGA-19 package footprint, pre-biased start-up capability, forced CCM operation for low ripple, PG/EN sequencing support, and 0.6V adjustable VOUT with ±1% FB reference accuracy.

Technical Context

The MPM3864GPQ-Z implements constant-on-time (COT) control with internal ramp compensation to achieve fast transient response and stable regulation without external loop compensation. Its valley-current-limit OCP and hiccup-mode recovery ensure robust fault handling under sustained overload.

It operates in forced continuous conduction mode (FCCM) across full load range, maintaining tight 1.2MHz switching frequency regardless of line or load variation. The integrated VCC LDO regulates from VIN down to 2.55V UVLO threshold, enabling reliable startup even at low input rails.

Key Specifications

Pinout & Package

ECLGA-19 (3mm × 3mm × 1.85mm) package with exposed thermal pad on bottom; requires solder paste stencil optimization and thermal vias to inner ground plane for 125°C junction operation at 6A.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar step-down power module applications.

Compared with TSM12060 and RTM2020B, the MPM3864GPQ-Z uniquely balances wide 2.75–7V input, 6A output, PG/EN sequencing, and configurable soft-start in a 3mm×3mm footprint - making it optimal for space-constrained FPGA and optical module designs requiring deterministic power-up behavior.

Availability

MPM3864GPQ-Z is available at Aetrix Electronics and suitable for FPGA core supplies, optical transceiver biasing, and industrial Ethernet PHY power requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for MPM3864GPQ-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 and modules, headquartered in Kirkland, WA, with global design and support centers.

The MPM3864 belongs to MPS's integrated power module product line, engineered for compact, high-current DC-DC conversion in space- and thermal-constrained applications such as networking, optical infrastructure, and programmable logic systems.

FAQ

What is the maximum recommended output capacitance for stable soft-start?

The MPM3864GPQ-Z supports up to 440µF total output capacitance when using a 47nF soft-start capacitor and 6A load, calculated per Equation (10) in the datasheet. Exceeding this limit risks failure to reach target VOUT before soft-start completes, triggering hiccup mode. Ceramic or POSCAP types are preferred for low ESR and predictable EMI behavior.

Does the device support forced discontinuous conduction mode (DCM)?

No - the MPM3864GPQ-Z operates exclusively in forced continuous conduction mode (FCCM) to maintain fixed 1.2MHz switching frequency across all load conditions. This eliminates variable-frequency artifacts and ensures consistent EMI filtering requirements, unlike adaptive CCM/DCM controllers.

How is thermal performance affected by PCB layout?

Thermal resistance θJA drops from 27.5°C/W (standard 4-layer board) to ≤18°C/W with ≥6 thermal vias under the exposed pad and 2oz copper pours on inner layers. Poor layout - such as insufficient PGND copper or missing vias - can raise junction temperature by >35°C at 6A, triggering thermal shutdown prematurely.

Can the PG pin drive an LED directly?

Yes - the PG pin sinks up to 4mA at 0.4V drop, sufficient to drive a standard green LED (2mA, 2.1V forward voltage) with a 1kΩ pull-up to 3.3V. However, for logic-level interfacing, a 100kΩ pull-up is recommended to minimize leakage-induced false asserts during low-power states.

Is the BST capacitor mandatory, and what value is required?

Yes - a 0.1µF X7R ceramic capacitor between BST and SW is mandatory to sustain high-side gate drive voltage. It must be placed within 2mm of the BST/SW pins with short, wide traces; failure to do so causes HS-FET dropout and catastrophic efficiency loss or thermal shutdown under load.

What happens during pre-biased start-up if VOUT > VREF before EN assertion?

The MPM3864GPQ-Z enters monotonic start-up: the internal BST refresh circuit recharges the bootstrap capacitor, and the SS capacitor charges in parallel with VOUT. Output regulation begins only after SS voltage exceeds sensed FB voltage - preventing reverse current and output collapse.

Does the part support output voltages below 0.6V?

No - the internal 600mV reference sets the absolute minimum VOUT at 0.6V. Attempting lower outputs via external scaling violates the FB input range specification and causes regulation failure. For sub-0.6V rails, a dedicated low-VOUT module (e.g., MPM3830) is required.