# OB2001WKCPA

**OB On Bright Elec** · AC-DC Controllers and Regulators · SOP-8

OB2001WKCPA from OB On Bright Elec, in a SOP-8. Pinout and pin descriptions extracted from the manufacturer datasheet by ds2sf; symbol, footprint, and 3D from KiCad-official CAD.

## Pinout

| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | VS | input | Connected to the source of the internal N-channel SR MOSFET; serves as the local ground/source reference for Vds sensing. Should be shorted to GND under the package before connecting to the output capacitor negative terminal. Absolute max: -0.6V to 7V. |
| 2 | VS | input | Second VS pin, connected to the source of the internal N-channel SR MOSFET. Doubled up for current handling and heat dissipation. Absolute max: -0.6V to 7V. |
| 3 | VD | input | Drain-voltage sense input for the N-channel SR MOSFET. Detects the negative body-diode drop (~-350 mV threshold to turn on, -5 mV threshold to turn off) to time SR gate switching. A 10 ohm 0805 series resistor between VD and Drain is recommended for ESD. Absolute max: -2.5V to 50V. |
| 4 | Drain | power_out | Drain of the internal SR MOSFET. Connects to the secondary-side winding of the flyback transformer. BVdss = 40 V, Rds(on) typ 15 mOhm. Absolute max: -0.6V to BVdss (self-clamped at -0.6V). |
| 5 | GND | power_in | Device ground reference for the controller logic and analog blocks. Return for VDD bypass and RT resistor. |
| 6 | VDD | power_in | Controller power supply. Recommended operating range 4V to 5.5V. UVLO(ON) typ 3.0V, UVLO(OFF) typ 3.1V. Operating current ~1.5 mA at 65 kHz. Requires a bypass capacitor placed close to the pin with its negative node returned directly to GND. Absolute max -0.6V to 7V. |
| 7 | Vin | input | System output voltage detection input for overshoot control. Trips a 1st overshoot clamp at ~5.65V (SR freq <7.5 kHz) and a 2nd clamp at ~6.15V, opening a ~70 mA discharge path from Vin to GND. Absolute max -0.6V to 7V. |
| 8 | RT | output | Minimum on-time programming pin. Connect a resistor from RT to GND to set the SR MOSFET minimum on time (Tonmin = 8 * RT * 1e-11; e.g. RT = 25 kOhm gives ~1.9 us). Internal reference voltage Vrt = 1.0V typ. Absolute max -0.6V to 7V. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | OB On Bright Elec |
| Package | SOP-8 |
| Category | PMIC |
| Pins | 8 |

## Ordering variants

Same part, different packaging or reel option.

- `OB2001WKCPA`

## CAD (KiCad official)

- Symbol: `OB2001WKCPA`
- Footprint: `Package_SO:SOIC-8_3.9x4.9mm_P1.27mm`
- 3D model: SOP-8 (KiCad packages3D, STEP)

## Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

- **Datasheet:** [OB On Bright Elec datasheet](docs/ob2001wkcpa-datasheet.pdf) (10 pp, sha256 `c4c7bad88806f8fa`, retrieved 2026-08-17, tier: lcsc)
- **Extractor:** `ds2sf` (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
- **CAD:** KiCad official libraries (CC-BY-SA 4.0).

[Datasheet PDF](docs/ob2001wkcpa-datasheet.pdf)