Single-cell Li-Ion USB charger — 500 mA ceiling, 10-VSON
The BQ24020DRCRG4 is a linear charger for single-cell Lithium Ion or Lithium Polymer packs, drawing power from a USB port. The charge current is programmable up to 500 mA, which means a typical 1000 mAh cell charges in about two hours — enough for compact handhelds where the 10-VSON (3x3 mm) footprint saves board area. Supply voltage maxes at 6.5 V, so the part tolerates the 5 V USB bus with margin for hot-plug transients. The charge termination voltage is fixed at 4.2 V — standard for Li-Ion cells. Over-temperature fault protection shuts down the pass element if the die exceeds the safe limit, which is a practical safeguard when the charger sits near a processor or radio.
Programmable current and timer — no I²C needed
Charge current and safety timer are set with external resistors, not a digital bus — the BQ24020DRCRG4 operates standalone. That simplifies the BOM for designs where a microcontroller is already present but not dedicated to charger management. The constant-current/constant-voltage profile is automatic; the part transitions to 4.2 V regulation once the cell reaches the voltage threshold. The junction temperature range spans -40°C to 125°C, which covers outdoor and under-hood environments.
Active production — sourcing through distribution
The part is available through franchised distribution; we source and quote to order against your BOM line — confirm the quantity and target lead time with an RFQ. No official second-source or pin-compatible alternative is listed in the bqTINY-II family, so the BOM position is single-sourced to TI.