Monolithic Power Systems Inc. MPF42791DRT-0B-0000-P

Overview

MPF42791DRT-0B-0000-P from Monolithic Power Systems is a 2–16 series-cell lithium-ion battery fuel gauge IC with integrated resistance detection, thermal modeling, and 5-level LED SOC indication. It estimates per-cell and pack state-of-charge (±2.5% accuracy with MP279x AFE), state-of-health, remaining runtime, charge time, and instantaneous available power. It operates from 2.5V supply and supports 400kHz I²C with CRC for robust host MCU communication in light EV and industrial energy storage systems.

For engineers reviewing the MPF42791DRT-0B-0000-P datasheet, MPF42791DRT-0B-0000-P pinout, MPF42791DRT-0B-0000-P application, or MPF42791DRT-0B-0000-P equivalent, key selection criteria include its 2–16-cell stack support, ±2.5% SOC accuracy when paired with MP279x AFEs, adaptive SOH/ESR learning, lifetime parameter logging, and dual I²C interface architecture with CHSL-controlled channel switching.

Technical Context

The MPF42791DRT-0B-0000-P implements a model-based fuel gauge algorithm that fuses cell voltage, current, and temperature inputs (supplied externally by an AFE like MP279x) to compute real-time SOC and SOH using embedded thermal and impedance models. Its execution is triggered via EXE_CMD from the host MCU, with results reported through dedicated registers including VRDG_CELLxx, IRDG_CELLxx, and TRDG_TSx.

It features two independent I²C slave interfaces: primary (SCL/SDA) for host MCU data exchange and secondary (SCLMON/SDAMON) for real-time monitoring or GUI configuration-enabled only when CHSL is pulled high. The device supports three operating modes-Active (4.3mA typical), Standby (50μA), and Disabled (6μA)-with CE pin control and IRQ-driven event notification.

Key Specifications

Pinout & Package

MPF42791DRT-0B-0000-P is housed in a thermally enhanced TQFN-32 (4mm × 4mm) package with exposed thermal pad (Pin 33) requiring solder connection to PCB ground plane for optimal thermal performance and EMI suppression.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar multi-cell lithium-ion fuel gauge applications.

Compared with BQ34Z100-G1 and MAX17055, MPF42791DRT-0B-0000-P uniquely integrates dual I²C channels for concurrent host/GUI access, on-die LED drivers eliminating external components, and adaptive thermal modeling specifically tuned for high-power industrial Li-ion stacks-making it optimal for cost-sensitive, thermally demanding BMS applications.

Availability

MPF42791DRT-0B-0000-P is available at Aetrix Electronics and suitable for light EVs, uninterruptible power supplies, industrial robotics, and cordless power tools requiring stable component supply, long-lifecycle support, and production-ready fuel gauge integration.

Supply support for MPF42791DRT-0B-0000-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, including DC/DC converters, battery monitors, and fuel gauges, with design centers in the US, China, and Taiwan.

The MPF42791 belongs to MPS's Battery Management Solutions product line, engineered for high-accuracy, multi-cell lithium-ion fuel gauging in industrial and mobility applications where thermal resilience, adaptive aging compensation, and system-level integration are critical.

FAQ

What AFEs are compatible with MPF42791DRT-0B-0000-P?

The MPF42791DRT-0B-0000-P is explicitly validated with MPS's MP279x family (MP2791DFP, MP2797DFP) for ±2.5% SOC accuracy. It accepts standardized cell voltage, current, and temperature inputs via host MCU registers (VRDG_CELLxx, IRDG_CELLxx, TRDG_TSx), so any AFE providing those parameters in correct format and timing can interface-though accuracy guarantees apply only to MP279x pairings.

How does the dual I²C interface function in practice?

The primary I²C (SCL/SDA) handles host MCU communication for configuration and data reads; the secondary (SCLMON/SDAMON) enables real-time monitoring or GUI-based tuning without interrupting host operations. Write access to the secondary channel requires CHSL pin high; otherwise, writes are ignored. Both channels share the same 7-bit address (0x08 default) but operate independently.

Can MPF42791DRT-0B-0000-P operate without an external MCU?

No. The MPF42791DRT-0B-0000-P is a fuel gauge co-processor requiring an external M0-class MCU (≥48KB Flash, ≥4KB RAM) to acquire sensor data from the AFE, synchronize execution timing (EXE_TIME), issue EXE_CMD triggers, and read output registers. It has no autonomous sensing or decision-making capability.

What is the role of the PB pin beyond LED triggering?

The PB (push-button) pin serves exclusively as a hardware trigger for immediate LED SOC display. When LEDS_ON_BTN is enabled, pulling PB low forces the LED drivers to reflect current pack SOC regardless of charge state or timer settings. It does not initiate calibration, reset, or configuration changes-only activates the visual indicator.

How is lifetime logging implemented and accessed?

Lifetime logging stores key parameters-including SOC history, SOH trends, temperature exposure, and cycle count-in on-chip non-volatile memory. Data is written automatically during normal operation and accessed via dedicated I²C registers (e.g., LOG_SOC, LOG_SOH). No external EEPROM or flash is required, and logs persist across power cycles and resets.

Does MPF42791DRT-0B-0000-P support LiFePO₄ chemistry?

Yes. The MPF42791DRT-0B-0000-P supports a wide variety of lithium chemistries, including LiFePO₄, NMC, NCA, and LCO. Its adaptive learning engine refines initial charge/discharge settings and SOH tracking for each chemistry type during field use, though factory calibration may require chemistry-specific configuration files provided by MPS FAEs.

What thermal management is required for reliable operation at 85°C?

At maximum junction temperature (85°C), the TQFN-32 package requires a minimum 400mm² copper pour connected to Pin 33 (exposed pad) and internal ground planes. Thermal resistance θJA is 47°C/W on a 4-layer PCB; derating is recommended above 70°C ambient to maintain <125°C junction temp. No heatsink is needed for typical industrial airflow.