Monolithic Power Systems Inc. EV2639A-R-00A

Overview

EV2639A-R-00A from Monolithic Power Systems is a reference design board for the MP2639AGR integrated 2-cell Li-ion/Li-polymer switching charger and bidirectional power manager. It implements boost-mode charging (2.5A at 5V input) and buck-mode discharge (5A at 5V output), with integrated 4-LED fuel gauge, thermal shutdown, battery temperature monitoring, and charge timer. It targets portable power-bank applications requiring seamless mode transition between USB-powered charging and battery-powered system supply.

For engineers reviewing the EV2639A-R-00A datasheet, EV2639A-R-00A pinout, EV2639A-R-00A application, or EV2639A-R-00A equivalent, this evaluation board enables rapid validation of MP2639A's dual-mode operation, input-current-limit programming via RILIM, charge-current setting via RISET, discharge-current limiting via ROLIM, and battery-voltage-based LED indication logic under real-world load and source conditions.

Technical Context

The EV2639A-R-00A implements a fully configured demonstration of the MP2639AGR IC in QFN4×4-26 package, supporting two distinct operating modes controlled by the MODE pin: charge mode (boost converter from 5V input to 8.4V battery) and discharge mode (buck converter from 8.4V battery to regulated 5V output). It integrates discrete components including Wurth 744323220 inductor, B330A Schottky diode, AM4825-P P-channel MOSFET, and Murata GRM31CR61E226KE15L 22μF output capacitors.

Board-level protection includes input over-voltage clamping (4.49V threshold set by R3/R4), battery over-voltage lockout at 8.4V ±0.5%, thermal shutdown, NTC-based battery temperature monitoring (RNTC1/RNTC2), and a programmable charge timer. The 4-LED driver circuit uses Yageo RC0603JR-072KL resistors to decode battery voltage into discrete fuel-level states.

Key Specifications

Availability

EV2639A-R-00A is available at Aetrix Electronics and suitable for power-bank development, portable device sub-battery integration, and USB-C PD accessory prototyping requiring stable component supply, pre-validated layout, and production-ready firmware-agnostic hardware.

Supply support for EV2639A-R-00A 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 analog and power ICs, with core expertise in DC/DC conversion, battery management, and motor control solutions for consumer, industrial, and automotive markets.

The EV2639A-R-00A belongs to MPS's evaluation board product line designed specifically to accelerate adoption of its integrated battery chargers-enabling fast functional verification, parameter tuning (RILIM/RISET/ROLIM), and system-level power-path validation without custom PCB spin.

FAQ

What is the primary function of the EV2639A-R-00A board?

The EV2639A-R-00A is a reference design board for the MP2639AGR IC, demonstrating bidirectional power management: it charges a 2-cell Li-ion battery from a 5V USB source at up to 2.5A, and discharges the battery to deliver 5V/5A to a load. It is not a standalone IC but a fully assembled, tested PCB with all critical passives, MOSFETs, and LED drivers pre-populated per the MP2639AGR datasheet recommendations.

How do I configure the input current limit for charging?

The input current limit is set by resistor RILIM connected to the ILIM pin of U1 (MP2639AGR). Using the formula I_{IN_LIM} = 640kΩ / R_ILIM, a 76.6kΩ resistor (RILIM = 76.6kΩ as listed in BOM) configures a 2.79A limit. This prevents overloading weak USB sources while maintaining priority for system power during charging.

Can the board operate without a microcontroller or external firmware?

Yes. The EV2639A-R-00A operates autonomously using hardwired configuration: MODE pin selects charge (low) or discharge (high); RILIM, RISET, and ROLIM set current limits; and the 4-LED fuel gauge responds directly to battery voltage without software. No MCU, firmware, or communication interface is required for basic functionality.

What battery types and configurations are supported?

The board is validated exclusively for 2-cell series Li-ion or Li-polymer batteries with nominal voltage 7.4V and full-charge voltage 8.4V. It supports battery voltage range 5.75–8.4V and includes NTC thermistor inputs (RNTC1/RNTC2) for temperature monitoring. It does not support single-cell, 3S+, or non-Li chemistries without redesign.

How is discharge mode enabled and controlled?

Discharge mode is activated by pulling the MODE pin high, then pressing push-button PB for <2.5 seconds. The board delivers regulated 5V to USB2/VL. Pressing PB >2.5 seconds disables discharge. During operation, short presses light LEDs for 5 seconds to indicate battery voltage level. Discharge terminates automatically after 16 seconds if load is removed from USB2.

Does the board include ESD or surge protection on USB input?

No. The EV2639A-R-00A has no dedicated ESD protection diodes or TVS devices on the USB input path (U2 micro-USB connector). System-level ESD robustness relies on the host USB port's protection and external design. For production use, designers must add appropriate IEC 61000-4-2 compliant protection upstream of the board's USB input.