ATTINY13A-SSU from Microchip, in a SOIC-8. Pinout and pin descriptions extracted from the manufacturer datasheet by ds2sf; symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin	Name	Type	Function
1	PB5/PCINT5/RESET/ADC0/dW	bidirectional	Port B bit 5, weak I/O pin. Muxed with active-low RESET input (low pulse > tRST triggers system reset), ADC channel 0 input, PCINT5 pin-change interrupt, and debugWIRE (dW) single-wire debug I/O. Tri-stated in reset.
2	PB3/PCINT3/CLKI/ADC3	bidirectional	Port B bit 3 with internal pull-up. Muxed with external clock input (CLKI) when the external-clock fuse is programmed, ADC channel 3 input, and PCINT3 pin-change interrupt.
3	PB4/PCINT4/ADC2	bidirectional	Port B bit 4 with internal pull-up. Muxed with ADC channel 2 input and PCINT4 pin-change interrupt.
4	GND	power_in	Ground reference. Connect to system 0V.
5	PB0/MOSI/AIN0/OC0A/PCINT0	bidirectional	Port B bit 0 with internal pull-up. Muxed with SPI/ISP MOSI (data-in during serial programming), analog comparator positive input AIN0, Timer/Counter0 compare-match output OC0A (PWM channel A), and PCINT0 pin-change interrupt.
6	PB1/MISO/AIN1/OC0B/INT0/PCINT1	bidirectional	Port B bit 1 with internal pull-up. Muxed with SPI/ISP MISO (data-out during serial programming), analog comparator negative input AIN1, Timer/Counter0 compare-match output OC0B (PWM channel B), external interrupt INT0, and PCINT1 pin-change interrupt.
7	PB2/SCK/ADC1/T0/PCINT2	bidirectional	Port B bit 2 with internal pull-up. Muxed with SPI/ISP serial clock SCK, ADC channel 1 input, Timer/Counter0 external clock/count input T0, and PCINT2 pin-change interrupt.
8	VCC	power_in	Positive supply, 1.8-5.5V. Decouple to GND with a 100nF ceramic close to the pin.

Key specifications

Parameter	Value
Manufacturer	Microchip
Package	SOIC-8
Category	MCU
Pins	8

Ordering variants

Same part, different packaging or reel option.

ATTINY13A-SSU
ATTINY13A-SSUR
ATTINY13A-SSUPU
ATTINY13A-SSUMMU
ATTINY13A-SSUMMUR
ATTINY13A-SSUMU
ATTINY13A-SSUMUR

CAD (KiCad official)

Symbol: ATTINY13A-SSU
Footprint: Package_SO:SOIC-8_3.9x4.9mm_P1.27mm
3D model: SOIC-8 (KiCad packages3D, STEP)

Provenance

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

Datasheet: Microchip datasheet (20 pp, sha256 1dfcd4b93e646f28, retrieved 2026-08-17, tier: lcsc)
Extractor: ds2sf (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF