# TPS3851H33EDRBT

**Texas Instruments** · Supervisor And Reset ICs · VSON-8-EP(3x3)

TPS3851H33EDRBT from Texas Instruments, in a VSON-8-EP(3x3). 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 | VDD | power_in | Supply voltage input, 1.6V to 6.5V range; add 0.1µF bypass capacitor for noisy applications. |
| 2 | CWD | input | Programmable watchdog timeout input; configure via external capacitor to GND, 10kΩ pull-up to VDD, or left unconnected; charging current 375nA typical; threshold 1.196-1.224V. |
| 3 | MR | input | Manual reset input with internal 500-700nA pull-up; logic low pulse (minimum 1µs) triggers RESET output; internally pulled high when unused. |
| 4 | GND | power_in | Ground reference; internally connected to thermal pad; connect thermal pad to large ground plane. |
| 5 | SET1 | input | Logic input to enable/disable watchdog timer; low <0.25V disables watchdog, high >0.8V enables operation; settling time 150µs when transitioning from disabled to enabled. |
| 6 | WDI | input | Watchdog timer input responsive to falling edge; minimum pulse duration 50ns; logic low <0.3×VDD, logic high >0.8×VDD; must be driven to VDD or GND when watchdog disabled. |
| 7 | WDO | output | Open-drain watchdog output driven low upon timeout for tRST delay (170-230ms) only when RESET is high, high-impedance when RESET low; maximum output low 0.4V at 3mA sink current. |
| 8 | RESET | output | Open-drain reset output driven low when VDD falls below undervoltage threshold VITN, released high-impedance after tRST delay (170-230ms); maximum output low 0.4V at 3mA; requires 1-100kΩ pull-up resistor. |
| 9 | Thermal Pad | passive | Exposed pad (from the footprint; not named in the datasheet pin table). |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Texas Instruments |
| Package | VSON-8-EP(3x3) |
| Category | Power Management (PMIC) |
| Pins | 9 |

## CAD (KiCad official)

- Symbol: `TPS3851H33EDRBT`
- Footprint: `Package_SON:VSON-8-1EP_3x3mm_P0.65mm_EP1.6x2.4mm`
- 3D model: VSON-8-EP(3x3), generated from the KiCad footprint (body from the F.Fab outline, terminals on the pads, 0.9 mm nominal VQFN height). Neither the vendor nor KiCad ships a 3D model for this package, so the dimensions are nominal, not the manufacturer's CAD (STEP)
- 3D model files: `tps3851h33edrbt-etched.step` / `tps3851h33edrbt-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `tps3851h33edrbt.step` / `tps3851h33edrbt.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/tps3851) (36 pp, sha256 `45ddb32c5436aeef`, retrieved 2026-10-07, tier: lcsc)
- **Datasheet language:** Chinese. Pin names, descriptions, and specs on this page were extracted and translated to English by ds2sf; the linked PDF is the manufacturer original.
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-haiku-4-5-20251001` (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/tps3851h33edrbt-datasheet.pdf)