MCP73831

@@ -0,0 +1,49 @@+# MCP73831++**Microchip Technology** · Li-Ion / LiPo battery charger · SOT-23-5++Miniature, fully integrated single-cell Li-Ion / Li-Polymer linear charge-management controller in a SOT-23-5 package. It regulates a 4.20 V constant-voltage float with a constant-current phase set by one resistor on PROG (up to 500 mA), and integrates the pass transistor, current sensing, and reverse-discharge protection. A STAT pin drives a charge-status LED. The default USB-powered LiPo charger for small devices; just add the PROG resistor and a status LED.++## Pinout++| Pin | Name | Type | Function |+|---|---|---|---|+| 1 | STAT | tri_state | Charge Status Output. Tri-state logic output on the MCP73831 (open-drain on MCP73832). Drives an indicator LED directly (ISINK up to 25 mA, VOL ≈ 0.4 V at 4 mA; ISOURCE up to 35 mA, VOH ≥ VDD-1 at 4 mA) or can be pulled up for interfacing to a host microcontroller. |+| 2 | VSS | power_in | Battery Management 0 V Reference. Connect to the negative terminal of the battery and the input supply return. |+| 3 | VBAT | power_out | Battery Charge Control Output. Connect to the positive terminal of the single-cell Li-Ion/Li-Polymer battery; this is the drain of the internal P-channel MOSFET pass transistor (RDSON ≈ 350 mΩ). Bypass to VSS with a minimum of 4.7 µF to ensure loop stability when the battery is disconnected. Regulated to VREG (4.20/4.35/4.40/4.50 V option) at ±0.75%. |+| 4 | VDD | power_in | Battery Management Input Supply. Recommended range [VREG(typical) + 0.3 V] to 6 V (absolute max 7 V). Bypass to VSS with a minimum of 4.7 µF. Supply current is 510 µA typical while charging. |+| 5 | PROG | input | Current Regulation Set and Charge Control Enable. A resistor from PROG to VSS programs the preconditioning, fast-charge, and termination currents (RPROG range 2 kΩ to 67 kΩ; e.g., 2 kΩ → 505 mA, 10 kΩ → 100 mA, 67 kΩ → 14.5 mA typical). Allowing PROG to float (impedance ≥ 70 kΩ, minimum shutdown impedance) disables the charge management controller. |++## Key specifications++| Parameter | Value |+|---|---|+| Type | Single-cell Li-Ion/LiPo linear charger |+| Regulation voltage | 4.20 V (-2 variant) |+| Charge current | Programmable via PROG (15-500 mA) |+| Integrated | Pass transistor, current sense, reverse-discharge protection |+| Status | STAT open-drain (charge LED) |+| Preconditioning + termination | Automatic |+| Package | SOT-23-5 |+| Body (L×W×H) | 2.9 × 1.6 × 1.1 mm |++## Ordering variants++- `MCP73831T-2ACI/OT (SOT-23-5, 4.20 V)`+- `MCP73831-2ACI/OT (SOT-23-5)`++## CAD (KiCad official)++- Symbol: `Battery_Management:MCP73831-2-OT`+- Footprint: `Package_TO_SOT_SMD:SOT-23-5`+- 3D model: SOT-23-5 (KiCad packages3D)++## Provenance++Data extracted from the manufacturer datasheet, not a distributor listing:++- **Datasheet:** [Microchip Technology datasheet](https://ww1.microchip.com/downloads/en/DeviceDoc/MCP73831-Family-Data-Sheet-DS20001984H.pdf) (29 pp, sha256 `75297f2a52355993`, retrieved 2026-08-17, tier: manufacturer)+- **Extractor:** `ds2sf` (Claude) — every pin and dimension is cited to a datasheet page; refuses to fabricate.+- **CAD:** KiCad official libraries (CC-BY-SA 4.0).++[Datasheet PDF](docs/mcp73831-datasheet.pdf)

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