Texas Instruments BQ33100PW

Overview

BQ33100 from Texas Instruments is a fully integrated super capacitor manager IC for 2- to 5-series stacks with individual cell monitoring and balancing, supporting up to 9-series stacks with stack-voltage-only measurement. It delivers active voltage balancing, 16-bit delta-sigma ADC-based V/I/T sensing, SMBus 1.1 interface, and integrated protection for overvoltage, overtemperature, short circuit, and excessive leakage - deployed in RAID systems, server blade cards, and UPS backup power.

For engineers reviewing the BQ33100 datasheet, BQ33100 pinout, BQ33100 application, or BQ33100 equivalent, key selection considerations include its 24-pin TSSOP package, 5-series cell balancing capability, ±10 mV capacitor voltage measurement accuracy (–10°C to 60°C), <660 µA normal-mode supply current, and firmware-configurable current protection thresholds via SMBus.

Technical Context

The BQ33100 implements a dual-oscillator architecture (2.097 MHz CPU clock + 32.768 kHz low-frequency oscillator) to support real-time coulomb counting, state-of-charge/health estimation, and RAM backup during power loss. Its analog front end includes a 16-channel multiplexer feeding a 16-bit delta-sigma ADC with dedicated inputs for SRP/SRN (current sense), TS (thermistor), VC1–VC5 (cell voltages), and RBI (RAM backup).

Protection logic combines hardware-fast response (e.g., 35–160 µs current fault detection) with firmware-configurable thresholds for overcurrent discharge (OCD), short-circuit charge/discharge (SCC/SCD), and thermal shutdown (125–175°C). Cell balancing uses internal pulldown drivers (0.85–5.7 kΩ) per VCx pin, enabling active equalization across up to five series-connected supercapacitors.

Key Specifications

Pinout & Package

Package: 24-pin TSSOP (PW), 7.8 mm × 4.4 mm body size, 0.65 mm pitch.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar super capacitor management applications.

Compared with BQ33100, BQ34Z100-G1 lacks supercap-specific balancing and voltage range scaling, while MAX17853 offers higher channel count but no SMBus integration or built-in SoH firmware - making BQ33100 uniquely suited for compact, self-contained supercapacitor backup systems requiring minimal host intervention.

Availability

BQ33100 is available at Aetrix Electronics and suitable for RAID systems, server blade cards, and UPS backup units requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for BQ33100 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 company specializing in analog, embedded processing, and power management technologies, with leadership in precision analog and battery management solutions.

The BQ33100 belongs to TI's supercapacitor management product line, designed specifically to replace discrete monitoring circuits in industrial backup power systems by integrating cell balancing, health analytics, and SMBus telemetry into a single 24-pin TSSOP IC.

FAQ

What is the maximum number of supercapacitors the BQ33100 can monitor with individual cell voltage sensing?

The BQ33100 supports individual voltage monitoring and active balancing for up to five series-connected supercapacitors using its VC1–VC5 pins. For configurations with six to nine series capacitors, it operates in stack-voltage-only mode without per-cell sensing - relying on external balancing or passive methods. This dual-mode capability makes the BQ33100 adaptable across diverse backup power architectures while maintaining accuracy and safety within its specified operating range.

Does the BQ33100 support both charge and discharge current protection?

Yes, the BQ33100 provides independent hardware-based protection for both charge and discharge paths. It detects short-circuit conditions during charging (SCC) and discharging (SCD) with configurable thresholds, plus overcurrent in discharge (OCD). Detection times are as fast as 35 µs for current faults, and all thresholds are programmable via SMBus registers. The BQ33100 also includes overvoltage, overtemperature, and excessive leakage monitoring - delivering comprehensive protection for supercapacitor-based hold-up systems.

How does the BQ33100 handle power loss during critical operations?

The BQ33100 uses its RBI (RAM Backup Input) pin to maintain data integrity during brief VCC interruptions. When an external capacitor is connected between RBI and GND, the internal DATA RAM retains configuration and telemetry even if main power drops below 3.2 V. Combined with its <1 µA shutdown current and REG27 LDO, the BQ33100 ensures continuous state-of-health tracking and fault logging - essential for applications like medical test equipment where data persistence is non-negotiable.

Can the BQ33100 be used with supercapacitor stacks exceeding 25 V total voltage?

No - the BQ33100's absolute maximum VCC rating is 34 V, but its recommended operating condition specifies VCC ≤ VVC2 + 5 V, and VCn–VC(n+1) ≤ 5 V per cell. With a maximum per-cell voltage of ~5 V and five cells, the practical stack limit remains ≤25 V. Exceeding this risks violating the differential voltage limits on VCx pins and may trigger internal protection or damage. For higher-voltage stacks, external level-shifting or cascaded BQ33100 devices are required - not supported natively by the BQ33100.

What communication protocol does the BQ33100 use, and is it compatible with standard microcontrollers?

The BQ33100 uses a 2-wire SMBus 1.1-compatible interface with open-drain SCL and SDA pins, operating at 10–100 kHz. It is fully compatible with standard I²C-capable microcontrollers, though SMBus-specific features like packet error checking and timeouts are optional. Host firmware can read real-time telemetry (voltage, current, temperature, SoC, SoH), configure protection thresholds, and trigger calibration routines - all without requiring proprietary hardware, making the BQ33100 straightforward to integrate into existing embedded systems using the BQ33100.