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AT42QT1244-MU

Microchip Tech · Touch Sensors · QFN-32-EP(5x5)

AT42QT1244-MU from Microchip Tech, in a QFN-32-EP(5x5). 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 M_SYNC input Mains sync input; if unused, connect to Vdd.
2 CHANGE output State change notification output, active low, with an internal 20 k - 50 k pull-up resistor; leave open if unused.
3 VSS power_in Ground.
4 VDD power_in Power supply; the regulator output capacitor should be kept close to pins 4 and 6.
5 VSS power_in Ground.
6 VDD power_in Power supply; the regulator output capacitor should be kept close to pins 4 and 6.
7 X6 output X matrix drive line; leave open if unused.
8 X7 output X matrix drive line; leave open if unused.
9 DBG_CLK output Debug clock output; leave open if unused.
10 VREF power_in Reference input; connect to Vss.
11 S_SYNC/DBG_DATA output Oscilloscope sync / debug data output; leave open if unused.
12 X0 output X matrix drive line; leave open if unused.
13 X1 output X matrix drive line; leave open if unused.
14 X2 output X matrix drive line; leave open if unused.
15 X3 output X matrix drive line; leave open if unused.
16 X4 output X matrix drive line; leave open if unused.
17 X5 output X matrix drive line; leave open if unused.
18 VDD power_in Power supply; a 100 nF capacitor should be placed close to this pin.
19 A1 input I2C address bit 1, read after reset.
20 VDD power_in Power supply.
21 VSS power_in Ground.
22 A0 input I2C address bit 0, read after reset.
23 Y0B bidirectional Y line connection; leave open if unused.
24 Y1B bidirectional Y line connection; leave open if unused.
25 Y2B bidirectional Y line connection; leave open if unused.
26 SMP output Sample output.
27 SDA output Serial data line (open-drain per datasheet).
28 SCL output Serial clock line (open-drain per datasheet).
29 RST input Active-low reset with an internal 30 k - 60 k pull-up resistor; should be controlled by the host, and may be left open or connected to Vdd.
30 Y0A bidirectional Y line connection; leave open if unused.
31 Y1A bidirectional Y line connection; leave open if unused.
32 Y2A bidirectional Y line connection; leave open if unused.
33 EP passive Exposed pad (from the footprint; not named in the datasheet pin table).

Key specifications

Parameter Value
Manufacturer Microchip Tech
Package QFN-32-EP(5x5)
Category Sensors
Pins 33

Electrical characteristics

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

Parameter Symbol Min Typ Max Unit Conditions Page
Operating temp -40 105 °C 47
Storage temp -55 125 °C 47
Vdd Vdd 6 V 47
Max continuous pin current -10 10 mA Any control or drive pin 47
Voltage forced onto any pin -0.5 V 47
EEPROM setups maximum writes 100000 write cycles 47
Vdd supply voltage Vdd 3 5 V 47
Supply ripple + noise 20 mV p-p 47
Cx transverse load capacitance per key Cx 2 20 pF 47
Low input logic level Vil 0.3 × Vdd 47
High input logic level Vih 0.6 × Vdd 47
Low output voltage Vol 0.6 V Vdd = 3.0 V 47
High output voltage Voh 2.3 V Vdd = 3.0 V 47
Input leakage current Iil 1 µA 47
Internal pull-up resistors (CHANGE pin) Rp 20 50 k Cs = 4.7 nF, Rs = 470 k, Ta = recommended range 48
Internal RST pull-up resistor Rrst 30 60 k Cs = 4.7 nF, Rs = 470 k, Ta = recommended range 48
Burst center frequency Fc 9.7 590 kHz Cs = 4.7 nF, Rs = 470 k, Ta = recommended range 48

Materials and finish

As the datasheet states them (page.json metadata.appearance; the 3D model's colours follow it).

Part Material Colour / plating Datasheet says Page
housing abs When a finger is sensed, the signal falls since the human body acts to absorb charge from the cross-coupling 29
contacts gold Pin 1 ID AU 3 51

CAD (KiCad official)

  • Symbol: AT42QT1244-MU
  • Footprint: Package_DFN_QFN:QFN-32-1EP_5x5mm_P0.5mm_EP3.3x3.3mm
  • 3D model: QFN-32-EP(5x5) (KiCad packages3D, STEP)
  • 3D model files: at42qt1244-mu-etched.step / at42qt1244-mu-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); at42qt1244-mu.step / at42qt1244-mu.glb are the bare package body.

Provenance

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

  • Datasheet: Microchip Tech datasheet (61 pp, sha256 c5b64a3fb868a3eb, retrieved 2026-10-29, tier: manufacturer)
  • 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