BQ7790509PWR

BQ7790509PWR is a standalone battery protector for packs of 3 to 5 cells, stackable to 20 cells, in a TSSOP-20 (PW) package. This 09 factory configuration sets the overvoltage threshold at 4.25 V with a 1 s delay and the undervoltage threshold at 2.5 V, and it adds open-wire detection for broken sense connections. Typical NORMAL current is only 6 µA, and the operating range is -40 C to +85 C. Because protection runs autonomously without a host processor or firmware, packs gain a hardware safety layer that keeps working during sleep, shipping and system faults, which reduces both safety risk and qualification effort for multi-cell products. Selection advice: order the 09 code only when its fixed 4.25 V overvoltage and 2.5 V undervoltage thresholds match your cell chemistry and pack design; other configuration codes in the same family set different thresholds, so a near-match code is not a drop-in substitute. Parameters verified against Texas Instruments documentation.