ATMEGA48PA-AU from Microchip, in a TQFP-32(7x7). 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	PD3/PCINT19/OC2B/INT1	bidirectional	Port D bit 3, general-purpose bidirectional I/O with internal pull-up. Alt: PCINT19 (pin-change interrupt), OC2B (Timer/Counter2 output-compare B / PWM), INT1 (external interrupt 1).
2	PD4/PCINT20/XCK/T0	bidirectional	Port D bit 4, general-purpose bidirectional I/O with internal pull-up. Alt: PCINT20, XCK (USART external clock), T0 (Timer/Counter0 external clock input).
3	GND	power_in	Digital ground (0 V) reference.
4	VCC	power_in	Digital supply voltage, 1.8 V to 5.5 V. Decouple locally to GND.
5	GND	power_in	Digital ground (0 V) reference.
6	VCC	power_in	Digital supply voltage, 1.8 V to 5.5 V. Decouple locally to GND.
7	PB6/PCINT6/XTAL1/TOSC1	bidirectional	Port B bit 6 with pull-up. Depending on CKSEL fuses, serves as XTAL1 (crystal oscillator input) or TOSC1 (async Timer/Counter2 oscillator input when AS2 is set). Otherwise general I/O.
8	PB7/PCINT7/XTAL2/TOSC2	bidirectional	Port B bit 7 with pull-up. Depending on CKSEL fuses, serves as XTAL2 (crystal oscillator output) or TOSC2 (async Timer/Counter2 oscillator when AS2 is set).
9	PD5/PCINT21/OC0B/T1	bidirectional	Port D bit 5, general-purpose bidirectional I/O with pull-up. Alt: PCINT21, OC0B (Timer/Counter0 output-compare B / PWM), T1 (Timer/Counter1 external clock input).
10	PD6/PCINT22/OC0A/AIN0	bidirectional	Port D bit 6, general-purpose bidirectional I/O with pull-up. Alt: PCINT22, OC0A (Timer0 output-compare A / PWM), AIN0 (analog comparator positive input).
11	PD7/PCINT23/AIN1	bidirectional	Port D bit 7, general-purpose bidirectional I/O with pull-up. Alt: PCINT23, AIN1 (analog comparator negative input).
12	PB0/PCINT0/CLKO/ICP1	bidirectional	Port B bit 0, general-purpose bidirectional I/O with pull-up. Alt: PCINT0, CLKO (system clock output when CKOUT fuse programmed), ICP1 (Timer/Counter1 input capture).
13	PB1/PCINT1/OC1A	bidirectional	Port B bit 1, general-purpose bidirectional I/O with pull-up. Alt: PCINT1, OC1A (Timer/Counter1 output-compare A / PWM).
14	PB2/PCINT2/SS/OC1B	bidirectional	Port B bit 2, general-purpose I/O with pull-up. Alt: PCINT2, /SS (SPI slave-select, active low), OC1B (Timer1 output-compare B / PWM). Must be input for SPI master mode.
15	PB3/PCINT3/OC2A/MOSI	bidirectional	Port B bit 3, general-purpose I/O with pull-up. Alt: PCINT3, OC2A (Timer2 output-compare A / PWM), MOSI (SPI master-out slave-in; also used for ISP serial programming).
16	PB4/PCINT4/MISO	bidirectional	Port B bit 4, general-purpose I/O with pull-up. Alt: PCINT4, MISO (SPI master-in slave-out; also used for ISP serial programming).
17	PB5/PCINT5/SCK	bidirectional	Port B bit 5, general-purpose I/O with pull-up. Alt: PCINT5, SCK (SPI serial clock; also used for ISP serial programming).
18	AVCC	power_in	Analog supply voltage for the ADC and PC3:0/ADC7:6. Must be within 0.3 V of VCC; connect to VCC through an LC filter when ADC is used.
19	ADC6	input	Analog-only input, ADC channel 6 (10-bit). Available in TQFP/QFN packages only.
20	AREF	passive	Analog reference input for the ADC. Decouple to GND (typ. 100 nF).
21	GND	power_in	Ground (0 V) reference (analog return).
22	ADC7	input	Analog-only input, ADC channel 7 (10-bit). Available in TQFP/QFN packages only.
23	PC0/ADC0/PCINT8	bidirectional	Port C bit 0, general-purpose bidirectional I/O with pull-up. Alt: ADC0 (10-bit ADC channel 0), PCINT8.
24	PC1/ADC1/PCINT9	bidirectional	Port C bit 1, general-purpose bidirectional I/O with pull-up. Alt: ADC1, PCINT9.
25	PC2/ADC2/PCINT10	bidirectional	Port C bit 2, general-purpose bidirectional I/O with pull-up. Alt: ADC2, PCINT10.
26	PC3/ADC3/PCINT11	bidirectional	Port C bit 3, general-purpose bidirectional I/O with pull-up. Alt: ADC3, PCINT11.
27	PC4/ADC4/SDA/PCINT12	bidirectional	Port C bit 4, general-purpose I/O with pull-up. Alt: ADC4, SDA (2-wire/I2C serial data), PCINT12.
28	PC5/ADC5/SCL/PCINT13	bidirectional	Port C bit 5, general-purpose I/O with pull-up. Alt: ADC5, SCL (2-wire/I2C serial clock), PCINT13.
29	PC6/RESET/PCINT14	input	Active-low external reset input (needs pulse ≥ min pulse width). When RSTDISBL fuse is programmed, functions as PC6 general-purpose I/O with different electrical characteristics; also PCINT14.
30	PD0/RXD/PCINT16	bidirectional	Port D bit 0, general-purpose bidirectional I/O with pull-up. Alt: RXD (USART receive data), PCINT16.
31	PD1/TXD/PCINT17	bidirectional	Port D bit 1, general-purpose bidirectional I/O with pull-up. Alt: TXD (USART transmit data), PCINT17.
32	PD2/INT0/PCINT18	bidirectional	Port D bit 2, general-purpose bidirectional I/O with pull-up. Alt: INT0 (external interrupt 0), PCINT18.

Key specifications

Parameter	Value
Manufacturer	Microchip
Package	TQFP-32(7x7)
Category	MCU
Pins	32

Ordering variants

ATMEGA48PA-AU
ATMEGA48PA-AUR
ATMEGA48PA-AUPU
ATMEGA48PA-AUMU
ATMEGA48PA-AUMMH
ATMEGA48PA-AUMUR

CAD (KiCad official)

Symbol: ATMEGA48PA-AU
Footprint: Package_QFP:LQFP-32_7x7mm_P0.8mm
3D model: TQFP-32(7x7) (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`atmega48pa-au.step`	413 KB	You want the bare part, or you mark your own boards.
`atmega48pa-au-etched.step`	3.3 MB	You want the part with `ATMEGA48PA-AU` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 864 faces against 507 in the bare model. It survives export, section views, and rendering in any CAD tool, and it drops straight into KiCad or Fusion with no extra setup.

Provenance

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

Datasheet: Microchip datasheet (26 pp, sha256 a4fd7bf8176c39b1, 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