# UCC3946DTR

**Texas Instruments** · Supervisor And Reset ICs · SOIC-8

UCC3946DTR from Texas Instruments, in a SOIC-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 | GND | power_in | Ground reference for the device. |
| 2 | RTH | input | Compares its voltage to an internal 1.25-V reference, so external resistors can program any desired reset threshold; the application information gives the threshold as VRESET = 1.235 V × (R1 + R2) / R2. |
| 3 | RES | output | Reset output is high only when RTH has risen above 1.235 V, stays low for the reset period once RTH rises above the threshold, and asserts low for an amount of time set by Figure 1 if RTH dips below 1.235 V. |
| 4 | RP | input | Programs the reset period with an external capacitor, where TRP = 3.125 × CRP (TRP in ms, CRP in nF) and CRP is charged by a 400-nA precision source. |
| 5 | WDO | output | Watchdog output is asserted low if WDI is not strobed or toggled within the watchdog period, and it returns high when RES is asserted. |
| 6 | WP | input | Programs the watchdog period with an external capacitor, where TWP = 25 × CWP (TWP in ms, CWP in nF). |
| 7 | WDI | input | Input to the watchdog timer; if it is not toggled or strobed within the watchdog period, WDO is asserted (VIH min 0.7×VDD, VIL max 0.3×VDD). |
| 8 | VDD | power_in | Supply voltage for the device, 2.0 V to 5.5 V for the UCC3946 with a minimum operating voltage of 1.0 V where RES is considered valid. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Texas Instruments |
| Package | SOIC-8 |
| Category | Power Management (PMIC) |
| Pins | 8 |

## CAD (KiCad official)

- Symbol: `UCC3946DTR`
- Footprint: `Package_SO:SOIC-8_3.9x4.9mm_P1.27mm`
- 3D model: SOIC-8 (KiCad packages3D, STEP)
- 3D model files: `ucc3946dtr-etched.step` / `ucc3946dtr-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `ucc3946dtr.step` / `ucc3946dtr.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/ucc3946) (20 pp, sha256 `6dea29f2ee7ad735`, 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/ucc3946dtr-datasheet.pdf)