Texas Instruments BQ40Z50RSMT

Overview

BQ40Z50RSMT from Texas Instruments is a fully integrated 1–4-series Li-ion/Li-polymer battery pack manager IC with Impedance Track™ gas gauging, high-side N-CH FET drive, integrated cell balancing, SMBus v1.1 interface, SHA-1 authentication, and TURBO BOOST mode. It performs real-time voltage, current, temperature, and capacity monitoring for smart battery packs in portable computing and medical devices.

For engineers reviewing the BQ40Z50RSMT datasheet, BQ40Z50RSMT pinout, BQ40Z50RSMT application, or BQ40Z50RSMT equivalent, this page delivers verified technical context, validated pin functions, confirmed protection thresholds (OCD/SCD/OCV), authentic alternative part comparisons, and design-meaningful specifications - all extracted from TI's production-grade SLUSBS8B datasheet (Nov 2019).

Technical Context

The BQ40Z50RSMT implements a dual-domain analog front-end: one path digitizes cell voltages (VC1–VC4) and pack voltage (PACK) via a precision 16-bit ADC with ±0.2% gain error and 15-bit effective resolution; another path integrates SRP–SRN differential voltage using a dedicated coulomb counter with ±5 µV offset error and 250-ms conversion time. Its AFE supports programmable overcurrent detection (OCD/SCD1/SCD2) with 128–256 µs trip delay and configurable wake thresholds down to ±0.625 mV.

It executes JEITA, adaptive, and enhanced charging algorithms while managing up to four thermistor inputs (TS1–TS4), PTC safety monitoring, Battery Trip Point (BTP) interrupts, and black-box diagnostic logging. The device operates across –40°C to +85°C with 2.2 V to 26 V supply range and enters SHUTDOWN mode at ≤1.6 µA quiescent current.

Key Specifications

Pinout & Package

Package: 32-pin VQFN (RSM), 4.00 mm × 4.00 mm with exposed thermal pad - optimized for compact battery pack PCB layouts and thermal dissipation in sealed enclosures.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar battery pack management applications.

Compared with BQ40Z50RSMT, the BQ40Z60RSMT extends cell count and safety features but increases firmware complexity, while the BQ34Z100-G1 reduces integration level and requires external FET control - making BQ40Z50RSMT the optimal balance of autonomy, footprint, and qualification readiness for 1–4S medical and computing packs.

Availability

BQ40Z50RSMT is available at Aetrix Electronics and suitable for notebook battery packs, portable medical monitors, industrial handheld scanners, and test equipment power modules requiring stable component supply and long-term lifecycle support.

Supply support for BQ40Z50RSMT 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

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and power management technologies with over 90 years of innovation in industrial, automotive, and computing markets.

The BQ40Z50RSMT belongs to TI's BQ family of battery management ICs, engineered specifically for single-chip, pack-integrated solutions that unify gas gauging, protection, authentication, and communication in space-constrained Li-ion applications.

FAQ

What is the primary function of the BQ40Z50RSMT in a battery pack?

The BQ40Z50RSMT serves as a complete pack-level battery manager - performing real-time gas gauging via Impedance Track™, controlling external CHG/DSG/PCHG FETs, enforcing programmable voltage/current/temperature protections, communicating over SMBus v1.1, and providing SHA-1 authentication. It replaces discrete gauging, protection, and security functions with a single IC, as confirmed in TI's SLUSBS8B datasheet Section 3.

Does the BQ40Z50RSMT support 4-cell lithium-ion battery configurations?

Yes, the BQ40Z50RSMT explicitly supports 1-series through 4-series Li-ion and Li-polymer configurations, as stated in its product title and Feature section of the official datasheet. Its VC1–VC4 pins provide dedicated voltage sensing for each cell in a 4S stack, and its protection logic scales accordingly - enabling direct use in quad-cell laptop and medical battery packs without external multiplexers.

How does the BQ40Z50RSMT achieve high-accuracy state-of-charge estimation?

The BQ40Z50RSMT achieves ±1% SOC accuracy using TI's patented Impedance Track™ algorithm, which dynamically models battery impedance across temperature, aging, and load conditions. This is enabled by its 16-bit ADC (±0.2% gain error), 250-ms coulomb counter conversion, and integrated temperature sensing (TS1–TS4). These hardware and algorithmic features are validated in TI's application reports SLUA927 and SLUAB34.

What protection features are programmable in the BQ40Z50RSMT?

The BQ40Z50RSMT offers fully programmable protection including overvoltage (per-cell and pack), undervoltage, overcurrent (OCD, SCD1, SCD2), short-circuit, charge timeout, FET overtemperature, and AFE faults - all configurable via SMBus commands and stored in nonvolatile memory. Timing parameters like OCD trip delay (128–256 µs) and thresholds are user-defined, as detailed in Sections 7.31–7.32 of the SLUSBS8B datasheet.

Is the BQ40Z50RSMT compatible with standard SMBus hosts?

Yes, the BQ40Z50RSMT implements a full SMBus v1.1 interface with SMBC and SMBD pins supporting standard command protocols (e.g., Read Word, Block Read), 100-kHz clock rate, and open-drain signaling with 1-MΩ internal pulldowns. It responds to standard SBS (Smart Battery System) commands and is interoperable with host controllers from Intel, AMD, and embedded microcontrollers without custom drivers.