Microchip Technology MCP73838T-FJI/MF

Overview

MCP73838T-FJI/MF from Microchip Technology is a fully integrated linear Li-Ion/Li-Polymer battery charge management controller with autonomous AC adapter or USB port source selection, ±0.5% voltage regulation accuracy, 4.20V fixed charge voltage, 100 mA–1 A programmable AC charge current, and Timer Enable (TE) pin for safety timer control. It operates in portable medical devices and ultra-mobile systems requiring dual-source charging with thermal regulation.

For engineers reviewing the MCP73838T-FJI/MF datasheet, MCP73838T-FJI/MF pinout, MCP73838T-FJI/MF application, or MCP73838T-FJI/MF equivalent, key selection criteria include its 10-lead 3 mm × 3 mm DFN package, TE pin functionality (absent on MCP73837), 4.20V regulation option, thermal shutdown at 150°C, and support for preconditioning and automatic recharge.

Technical Context

The MCP73838T-FJI/MF implements a CC/CV charge algorithm with factory-set 4.20V regulation, selectable preconditioning (10% of I_REG), and termination at 5% of I_REG. Its autonomous power source selection prioritizes VAC over VUSB, and it integrates pass transistors, current sense (G = 0.001), reverse discharge protection, and LDO mode.

Thermal regulation dynamically limits charge current above die temperature thresholds, while the TE pin enables/disables the safety timer (4/6/8 hr options). Battery temperature monitoring uses a 50 µA thermistor bias current with dual-voltage comparators (VT1 = 1.23 V, VT2 = 0.25 V) for NTC-based thermal fault detection.

Key Specifications

Pinout & Package

Package: 10-Lead 3 mm × 3 mm DFN with exposed thermal pad (EP), internally connected to VSS. Requires PCB thermal pad connection to ground plane for optimal thermal performance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Li-ion linear charge management applications.

Compared with MCP73837T-FJI/MF, the MCP73838T-FJI/MF trades PG output for TE control-enabling hardware-based timer enforcement without MCU involvement. Versus BQ24075RGTR, it offers tighter source arbitration and integrated thermal foldback but lower max current, making it preferable for thermally constrained, safety-focused designs.

Availability

MCP73838T-FJI/MF is available at Aetrix Electronics and suitable for smartphones, portable medical devices, and ultra-mobile devices requiring stable component supply, long-term lifecycle support, and automotive-grade reliability validation.

Supply support for MCP73838T-FJI/MF 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

Microchip Technology is a leading provider of microcontrollers, analog, FPGA, and connectivity solutions, serving industrial, automotive, communications, and consumer markets with high-reliability silicon and development tools.

The MCP73837/8 product line delivers standalone, highly accurate linear battery chargers optimized for space-constrained portable electronics with dual-input power sources and stringent safety requirements.

FAQ

What distinguishes MCP73838T-FJI/MF from MCP73837T-FJI/MF?

The MCP73838T-FJI/MF features a Timer Enable (TE) pin for hardware-controlled safety timer activation, whereas the MCP73837T-FJI/MF substitutes a Power-Good (PG) output. Both share identical 4.20V regulation, 10-lead DFN packaging, and dual-source selection logic-but only MCP73838T-FJI/MF allows direct timer enable/disable without MCU firmware intervention.

Does MCP73838T-FJI/MF support 4.35V or other charge voltage options?

No. The MCP73838T-FJI/MF is specifically configured for 4.20V ±0.5% regulation. Other voltage options (4.35V, 4.40V, 4.50V) are implemented in different part numbers within the MCP73837/8 family-such as MCP73838T-2FCI/MF for 4.35V-and are not interchangeable with MCP73838T-FJI/MF.

How is the safety timer duration selected on MCP73838T-FJI/MF?

The MCP73838T-FJI/MF supports 4-hour, 6-hour, or 8-hour safety timer durations, factory-configured per part number. The TE pin enables or disables the timer but does not adjust its duration. Duration selection is fixed at manufacturing; users must choose the appropriate variant (e.g., -FJI = 4 hr, -FCI = 6 hr) based on battery capacity and thermal profile.

Can MCP73838T-FJI/MF charge batteries without a thermistor connected?

Yes. The THERM pin is optional. If left unconnected or pulled to VSS, the thermistor comparator is disabled and thermal monitoring is inactive. All other charging functions-including CC/CV, source selection, and timer-operate normally. However, this removes overtemperature protection, so use only in thermally benign environments.

What is the minimum bypass capacitance required at VBAT for stable operation of MCP73838T-FJI/MF?

The MCP73838T-FJI/MF requires a minimum 1 µF ceramic capacitor between VBAT and VSS for loop stability, especially when the battery is disconnected. For I_OUT > 250 mA, Microchip recommends ≥4.7 µF to ensure robust transient response and reduce output ripple during load steps.