Single-cell Li-Ion protector in a 1.5 mm square package
The Texas Instruments BQ29737DSET is a single-cell lithium-ion/polymer battery protection IC built for portable and industrial packs. It monitors one series cell and triggers protection on over-current, over-voltage, under-voltage, and short-circuit conditions — the four fault modes a 1S Li-Ion pack needs to survive charging and discharging without venting or degrading. The part comes in a 6-WFDFN package measuring 1.5 x 1.5 mm, which is small enough to fit inside a battery-pack flex or a handheld-device PCB. The operating temperature range of -40°C to 85°C covers industrial enclosures, outdoor portable gear, and consumer electronics — but not automotive under-hood, where the BQ79612PAPRQ1's 125°C rating would be needed.
Protection logic and BOM fit
The fault protection block handles the four events a 1-cell Li-Ion protection IC must manage: over-current during discharge, over-voltage during charge (cell overcharge), under-voltage (deep discharge cutoff), and short-circuit. There is no integrated fuel gauge, no SMBus communication, and no cell balancing — this is a pure protection switch controller, not a monitor. The BOM decision is straightforward: if the design needs only a hardware protection fence around the cell, this IC fits; if it also needs state-of-charge reporting or multi-cell balancing, look at the BQ2084 series (2–4 cells, SMBus) instead. Surface-mount assembly in the 6-WFDFN footprint keeps the placement compatible with standard reflow profiles. The Tape & Reel supply is the typical channel for volume production; Cut Tape (CT) is available for prototype or low-volume builds. No separate heat sink is needed — the package relies on the PCB copper for thermal dissipation at the protection FET's dissipation level.
Lifecycle and sourcing posture
The BQ29737DSET carries an active lifecycle status, meaning Texas Instruments continues to manufacture it with no announced last-time-buy or end-of-life notice. Channel supply is normal — no allocation risk flagged. For dual-sourcing or a higher-temperature variant, the BQ79612PAPRQ1 (AEC-Q100, -40°C to 125°C) is a functional alternative but not a pin-for-pin drop-in; it adds SPI/UART communication and over-temperature protection, which changes the BOM interface requirements. Because this is an active, single-sourced TI part, the procurement risk is low as long as the BOM stays within TI's standard distribution. No minimum order quantity beyond the reel increment applies for standard orders.