Monolithic Power Systems Inc. EVM82504-BH-03A

Overview

EVM82504-BH-03A from Monolithic Power Systems is a split-input, 200A output evaluation board for the MPM82504 quad 25A synchronous step-down power module. It demonstrates dual-input operation (VIN1/VIN2 = 10.8–13.2V), configurable 0.85V output, 600kHz default switching frequency, and active current balancing across up to four paralleled modules-targeting PCIe card power delivery with auxiliary 12V support.

For engineers reviewing the EVM82504-BH-03A datasheet, EVM82504-BH-03A pinout, EVM82504-BH-03A application setup, or EVM82504-BH-03A equivalent evaluation platforms, this board provides validated dual-mode operation (200A dual-input / 50A single-input), PMBus-enabled monitoring via integrated MPM3632C bias supply, and direct interface to 6-pin/8-pin PCIe AUX connectors for real-world system integration testing.

Technical Context

The EVM82504-BH-03A implements a scalable, split-rail architecture using two MPM82504GBH modules (each quad 25A) to deliver up to 200A at 0.85V from dual 12V inputs. It integrates input detection circuitry, automatic mode selection (dual/single input), and a dedicated MPM3632C-based 5V bias supply that powers control logic when VIN2 is absent.

Operation relies on SENSE pin detection from PCIe AUX connectors to enable/disable SWITCH2 and configure current sharing. The board supports PMBus communication via an optional 10-pin header and includes full thermal management, input/output capacitor banks (22μF–100μF ceramic/polymer), and precision 2mΩ current-sense resistors for accurate ISUM monitoring across all eight phases.

Key Specifications

Availability

EVM82504-BH-03A is available at Aetrix Electronics and suitable for PCIe card development, high-current server VRM validation, multi-rail power architecture prototyping, and industrial embedded power subsystem qualification requiring stable component supply and documented reference design fidelity.

Supply support for EVM82504-BH-03A 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, with core expertise in integrated DC/DC solutions for computing, telecom, and industrial applications.

The EVM82504-BH-03A belongs to MPS's evaluation platform series for scalable, high-density power modules-designed specifically to accelerate adoption of split-input architectures in PCIe Gen4/Gen5 add-in cards and AI accelerator boards.

FAQ

What is the primary function of the MPM3632C on this board?

The MPM3632C provides a regulated 5V bias supply to maintain control circuit operation during single-input mode when VIN2 is disconnected. It connects to VIN2 through a diode and is enabled via SWITCH2, ensuring logic power remains active for phase management and PMBus communication even without auxiliary input.

How does the board detect whether the PCIe AUX power cable is connected?

It uses the SENSE pin from the 6-pin or 8-pin PCIe AUX connector, pulled up to 3.3V via a 10kΩ resistor. This signal drives the CTRL pin of the MPM3632C and controls SWITCH2 state-enabling the 5V bias supply only when no AUX power is detected, as defined in Tables 1 and 2 of the reference document.

Can the output voltage be adjusted, and how?

Yes-VOUT is set by an external resistor divider network connected to the VOSENSE pins. The default configuration yields 0.85V, but values can be recalculated using the MPM82504's feedback equation (VREF = 0.6V). Resistor values R92 (2.4kΩ) and R95 (0Ω) are shown in Figure 7; R95 may be replaced to adjust scaling.

What is the role of the 2mΩ sense resistors (e.g., R20, R27)?

These precision film resistors serve as current-sense elements for the ISUM pins of each MPM82504 quadrant. They enable accurate measurement of per-phase current and facilitate active current balancing across paralleled modules-critical for thermal uniformity and derating compliance at 200A total output.

Does the board support PMBus communication out of the box?

Yes-the board includes a 10-pin PMBus header (PMBUS) with labeled SCL, SDA, ALT, GND, and VCC_3V3 pins. No soldering or configuration is required beyond connecting a compliant PMBus host; all MPM82504 instances are pre-wired for addressable communication via ADDR1–ADDR4 pins.

What thermal management features are implemented?

The board uses 15mm × 30mm BGA-packaged MPM82504GBH modules with exposed thermal pads soldered directly to internal copper planes. It includes 12-layer PCB stack-up (Figures 11–18), extensive ground/power planes, and thermal vias under each module-validated for continuous 200A operation with forced airflow or heatsink attachment per MPS thermal guidelines.