Microchip Technology MCP73826-4.1VCHTR

Overview

MCP73826-4.1VCHTR from Microchip Technology is a linear single-cell lithium-ion battery charge management controller in a 6-pin SOT-23A package, featuring ±1% voltage regulation accuracy at 4.1 V, programmable fast-charge current via external sense resistor, and automatic preconditioning for deeply depleted cells down to 2.4 V. It operates from 4.5 V to 5.5 V input and supports industrial temperature range (–20°C to +85°C), used in space-constrained portable electronics requiring standalone charging with thermal safety.

For engineers reviewing the MCP73826-4.1VCHTR datasheet, MCP73826-4.1VCHTR pinout, MCP73826-4.1VCHTR application, or MCP73826-4.1VCHTR equivalent, key selection criteria include fixed 4.1 V regulation for coke-anode Li-ion cells, external P-channel MOSFET drive capability (VDRV), precision cell voltage monitoring (VBAT), current-sense input (VSNS), and logic-controlled shutdown (SHDN) - all critical for low-cost, thermally constrained charger designs.

Technical Context

The MCP73826-4.1VCHTR implements a three-phase charge algorithm: preconditioning (foldback current at ~43% of peak I_OUT when V_BAT < 2.4 V), controlled-current fast charge (regulated by VSNS voltage drop across R_SENSE), and constant-voltage regulation (4.1 V ±1% over –20°C to +85°C). Its analog control loop uses internal 1.2 V reference and precision resistor dividers (340.5 kΩ for 4.1 V version) to maintain voltage accuracy independent of supply variation.

It drives an external P-channel MOSFET via VDRV (capable of 0.08 mA sink / 1 mA source in CV mode), monitors battery voltage directly at VBAT with ≥10 µF bypass for stability, and enters auto power-down when VIN falls below VBAT - eliminating reverse battery drain. Shutdown input (SHDN) enables host-controlled charge initiation/termination with sub-1 µA leakage and 0.5 µA shutdown current.

Key Specifications

Pinout & Package

6-pin SOT-23A package (EIAJ SC-74), tape-and-reel (TR) format, marked "MCP73826-4.1VCH" per Microchip DS21705B-page 14.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP73826-4.2VCHTR, the MCP73826-4.1VCHTR provides chemically matched 4.1 V regulation essential for coke-anode cells, while versus BQ24040DRVR it offers discrete MOSFET control, lower shutdown current, and proven compatibility with legacy portable designs - but requires external FET and thermal design oversight.

Availability

MCP73826-4.1VCHTR is available at Aetrix Electronics and suitable for personal data assistants, cellular telephones, and hand held instruments requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MCP73826-4.1VCHTR 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 Inc. is a U.S.-based semiconductor manufacturer specializing in microcontrollers, analog devices, and battery management ICs, with global distribution and design support infrastructure.

The MCP738xx family delivers cost-optimized, space-efficient linear charge controllers for single-cell Li-ion applications - designed specifically for portable electronics where simplicity, small footprint, and battery chemistry-specific voltage accuracy outweigh the efficiency benefits of switching topologies.

FAQ

What is the exact voltage regulation setting of the MCP73826-4.1VCHTR?

The MCP73826-4.1VCHTR is factory-trimmed to regulate at 4.1 V with ±1% accuracy over –20°C to +85°C ambient temperature and 4.5 V to 5.5 V input voltage. This value is fixed and non-adjustable; it corresponds to the internal 340.5 kΩ feedback resistor network specified in DS21705B-page 3, Note 1. The MCP73826-4.1VCHTR must be used exclusively where 4.1 V termination is required by the battery chemistry.

How does the MCP73826-4.1VCHTR handle deeply discharged batteries?

The MCP73826-4.1VCHTR initiates preconditioning when the VBAT pin reads below 2.4 V (typical), applying a reduced charge current scaled to ~43% of the programmed fast-charge level. This foldback current minimizes heat dissipation in the external P-MOSFET and protects the Li-ion cell from damage during recovery. Preconditioning continues until VBAT exceeds 2.4 V, after which the device transitions to controlled-current fast charge.

Can the MCP73826-4.1VCHTR operate without a microcontroller?

Yes, the MCP73826-4.1VCHTR is designed for stand-alone operation: tie SHDN to VIN to enable automatic charging upon input application, and rely on its built-in three-phase algorithm (preconditioning → fast charge → constant voltage) for full battery management. No firmware or host control is required, though SHDN remains available for optional MCU coordination of charge start/stop or recharge cycles.

What external components are mandatory for basic operation of the MCP73826-4.1VCHTR?

Four external components are mandatory: (1) an external P-channel MOSFET (e.g., NDS8434) driven by VDRV, (2) a precision current-sense resistor (R_SENSE) between VIN and MOSFET source to set fast-charge current, (3) ≥10 µF capacitor from VBAT to GND for loop stability, and (4) ≥10 µF capacitor from VIN to GND for supply decoupling. The SHDN pin may be tied directly to VIN for always-on operation.

Does the MCP73826-4.1VCHTR provide reverse battery protection?

No, the MCP73826-4.1VCHTR does not include reverse battery or reverse-input protection. Its architecture relies on the body diode of the external P-channel MOSFET for basic reverse-current blocking, but this is insufficient for fault conditions. Microchip recommends adding an external Schottky diode in series with VIN (as shown in DS21705B-page 13, Figure 6-1) to prevent battery discharge through the MOSFET body diode during input short or reverse polarity events.