# AT42QT2120-XUR

**Microchip Tech** · Touch Sensors · TSSOP-20

AT42QT2120-XUR from Microchip Tech, in a TSSOP-20. 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 | KEY8/GPO6 | bidirectional | Comms mode: Key 8 / general-purpose output (standalone mode: OUT3, push-pull output for key 3); leave open if unused. |
| 2 | KEY7/GPO5 | bidirectional | Comms mode: Key 7 / general-purpose output (standalone mode: OUT2, push-pull output for key 2); leave open if unused. |
| 3 | KEY6/GPO4 | bidirectional | Comms mode: Key 6 / general-purpose output (standalone mode: Key 6); leave open if unused. |
| 4 | KEY5/GPO3 | bidirectional | Comms mode: Key 5 / general-purpose output (standalone mode: Key 5); leave open if unused. |
| 5 | KEY4/GPO2 | bidirectional | Comms mode: Key 4 / general-purpose output (standalone mode: Key 4); leave open if unused. |
| 6 | KEY3/GPO1 | bidirectional | Comms mode: Key 3 / general-purpose output (standalone mode: Key 3); leave open if unused. |
| 7 | KEY2/GPO0 | bidirectional | Comms mode: Key/slider/wheel 2 / general-purpose output (standalone mode: Key 2); leave open if unused. |
| 8 | KEY1 | bidirectional | Comms mode: Key/slider/wheel 1 (standalone mode: GUARD channel); leave open if unused. |
| 9 | KEY0 | bidirectional | Comms mode: Key/slider/wheel 0 (standalone mode: PROX proximity channel); leave open if unused. |
| 10 | VSS | power_in | Ground. |
| 11 | VDD | power_in | Power supply, 1.8 V to 5.5 V. |
| 12 | MODE | input | Mode selection pin: connect to Vss for Comms mode, connect to Vdd for Standalone mode. |
| 13 | SDA | bidirectional | Comms mode: open-drain I2C serial interface data, pull up to Vdd (unused in standalone mode). |
| 14 | RESET | input | Active-low reset with internal 60 kΩ pull-up; tie to Vdd if unused. |
| 15 | N/C | unconnected | Comms mode: no connection (standalone mode: PXOUT, open-drain output for the proximity channel); leave open. |
| 16 | SCL | bidirectional | Comms mode: open-drain I2C serial interface clock, pull up to Vdd (unused in standalone mode). |
| 17 | CHANGE | output | Comms mode: active-low open-drain state change interrupt requiring an external pull-up resistor (unused in standalone mode). |
| 18 | KEY11/GPO9 | bidirectional | Comms mode: Key 11 / general-purpose output (standalone mode: OUT6, push-pull output for key 6); leave open if unused. |
| 19 | KEY10/GPO8 | bidirectional | Comms mode: Key 10 / general-purpose output (standalone mode: OUT5, push-pull output for key 5); leave open if unused. |
| 20 | KEY9/GPO7 | bidirectional | Comms mode: Key 9 / general-purpose output (standalone mode: OUT4, push-pull output for key 4); leave open if unused. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Microchip Tech |
| Package | TSSOP-20 |
| Category | Sensors |
| Pins | 20 |

## Electrical characteristics

Limits as printed in the datasheet (page.json `metadata.characteristics` carries them as data).

| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Supply voltage Vdd | Vdd | -0.5 |  | 6 | V |  | 30 |
| Max continuous pin current, any control or drive pin |  | -10 |  | 10 | mA |  | 30 |
| Storage temperature |  | -55 |  | 125 | °C |  | 30 |
| Operating temperature |  | -40 |  | 85 | °C |  | 30 |
| Supply voltage Vdd | Vdd | 1.8 |  | 5.5 | V |  | 30 |
| Supply ripple+noise |  | -25 |  | 25 | mV |  | 30 |
| Cx load capacitance per key | Cx | 1 |  | 30 | pF | per key | 30 |
| Low output voltage | Vol |  |  | 0.6 | V |  | 30 |
| Input leakage current | Iil | -1 |  | 1 | µA |  | 30 |
| Sample frequency | FQT | 10.5 | 12.5 |  | kHz | Modulated spread-spectrum (chirp) | 31 |
| I2C-compatible clock rate | FI2C |  |  | 400 | kHz |  | 31 |
| Burst modulation, percentage | Fm | 15 |  |  | % |  | 31 |
| RESET pulse width |  | 2 |  |  | µs | 2 µs at 1.8 V | 31 |

## CAD (KiCad official)

- Symbol: `AT42QT2120-XUR`
- Footprint: `Package_SO:TSSOP-20_4.4x6.5mm_P0.65mm`
- 3D model: TSSOP-20 (KiCad packages3D, STEP)
- 3D model files: `at42qt2120-xur-etched.step` / `at42qt2120-xur-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `at42qt2120-xur.step` / `at42qt2120-xur.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Microchip Tech datasheet](https://ww1.microchip.com/downloads/en/DeviceDoc/doc9634.pdf) (46 pp, sha256 `2ae816b6e110f11c`, retrieved 2026-11-08, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-sonnet-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/at42qt2120-xur-datasheet.pdf)