# UCC2809PWTR-1

**Texas Instruments** · AC-DC Controllers & Regulators · TSSOP-8

UCC2809PWTR-1 from Texas Instruments, in a TSSOP-8. Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.

## Pinout

| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | FB | input | Summing node for current sense feedback, optocoupler voltage feedback and slope compensation, compared against a 1V threshold; an internal 250 on-resistance NMOS discharges external leading-edge-blanking capacitance during PWM off time. |
| 2 | SS | passive | Soft-start timing capacitor node, charged by an internal 6µA current source; if taken below 0.5V the output driver is inhibited and held low. |
| 3 | RT1 | passive | Connects timing resistor RT1 and sets the oscillator positive ramp time, Tr = 0.74 × (CT + 27pF) × RT1; minimum recommended value is 10kΩ. |
| 4 | RT2 | passive | Connects timing resistor RT2 and sets the oscillator negative ramp time, Tf = 0.74 × (CT + 27pF) × RT2; minimum recommended value is 4.32kΩ. |
| 5 | GND | power_in | Reference ground and power ground for all functions of the device. |
| 6 | OUT | output | High-current power driver output for an N-channel MOSFET, with a minimum series gate resistor of 3.9 recommended and an absolute IOUT limit of -0.4A to 0.8A (tpw < 1µs, duty cycle < 10%). |
| 7 | VDD | power_in | Power input, shunt-regulated at 17.5V (absolute maximum VDD 19V), to be bypassed with a 1µF ceramic capacitor. |
| 8 | REF | power_out | Buffered internal 5V reference output (5.0V typical, 4.75V to 5.25V), to be bypassed with at least a 0.47µF ceramic capacitor. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Texas Instruments |
| Package | TSSOP-8 |
| Category | Power Supply Chip |
| Pins | 8 |

## CAD (KiCad official)

- Symbol: `UCC2809PWTR-1`
- Footprint: `Package_SO:TSSOP-8_3x3mm_P0.65mm`
- 3D model: TSSOP-8 (KiCad packages3D, STEP)
- 3D model files: `ucc2809pwtr-1-etched.step` / `ucc2809pwtr-1-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `ucc2809pwtr-1.step` / `ucc2809pwtr-1.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Texas Instruments datasheet](https://www.ti.com/cn/lit/gpn/ucc2809-2) (24 pp, sha256 `7fc852aa75a77966`, retrieved 2026-10-08, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-haiku-5-5` (text), consensus `claude-sonnet-5-5` (agreed), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish.
- **CAD:** KiCad official libraries (CC-BY-SA 4.0).

[Datasheet PDF](docs/ucc2809pwtr-1-datasheet.pdf)