ATMEGA48PA-AU - 8-Bit AVR 20MHz 4KB Flash MCU | Microchip
MPN: ATMEGA48PA-AU β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.15 | $2.15 |
| 10 | $1.94 | $19.40 |
| 100 | $1.72 | $172.00 |
| 500 | $1.55 | $775.00 |
| 1,000 | $1.38 | $1,380.00 |
ATMEGA48PA-AU Overview
An 8-bit microcontroller is a single-chip computer that integrates a CPU core, program memory, data memory, and peripherals such as timers, serial interfaces, and analog-to-digital converters. Within the semiconductor taxonomy, the ATmega48PA sits in the AVR family, which belongs to the 8-bit microcontroller class, itself a subset of embedded processors and microcontrollers. The picoPower architecture is designed for battery-powered and always-on embedded systems where deterministic real-time response matters more than raw throughput.
Key features include 4 KB ISP Flash with 10,000 write/erase cycles, 256 bytes EEPROM with 100,000 write cycles, 512 bytes SRAM, 23 programmable I/O lines, and three flexible timer/counters with compare and PWM modes. The device integrates a 10-bit ADC with 8 channels, a programmable watchdog timer, and internal calibrated RC oscillator, reducing external component count.
The ATmega48PA uses the AVR enhanced RISC architecture with 131 powerful instructions, most executing in a single clock cycle, achieving up to 20 MIPS at 20 MHz. The picoPower technology delivers sub-1 uA power-down current, making it suitable for battery-operated sensor nodes and portable instruments.
Typical applications include industrial control panels, consumer appliance control, battery management, sensor signal conditioning, and low-power IoT edge nodes. The 32-pin TQFP footprint is shared across the ATmega48PA/88PA/168PA/328P family, allowing firmware and PCB reuse with memory scaling.
When designing with this device, decouple every VCC pin with a 100 nF ceramic capacitor placed close to the pin, and use a 10 uF bulk capacitor on the board rail. The internal 8 MHz RC oscillator can eliminate the external crystal in cost-sensitive designs, but external crystals are recommended when UART baud accuracy or USB timing is critical.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet, giving engineers a single reference for selection, replacement, and layout decisions.
Drop-in alternatives for ATMEGA48PA-AU β same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with ATMEGA48PA-AU (same form factor and footprint) β differing in Serial Interfaces, Package, EEPROM, SRAM, Timers/Counters.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATMEGA88PA-AU
β Drop-Inπ Reference alternative (not in catalog)
ATMEGA168PA-AU
β Drop-Inβ In Stock
$0.98 / Unit
View Datasheet βATMEGA328P-AU
β Drop-Inβ In Stock
$1.85 / Unit
View Datasheet βATMEGA48-20AU
β Drop-Inβ In Stock
$1.6 / Unit
View Datasheet βATMEGA48PA-AU Maximum Ratings & Electrical Characteristics
| Core Processor | AVR 8-bit RISC |
| Program Memory Size | 4 KB (2K x 16) Flash |
| EEPROM Size | 256 B |
| SRAM Size | 512 B |
| Maximum Clock Frequency | 20 MHz |
| Operating Voltage Range | 1.8 V to 5.5 V |
| Supply Voltage (5V operation) | 4.5 V to 5.5 V |
| Number of I/O Lines | 23 |
| General Purpose Working Registers | 32 |
| Instruction Set | 131 instructions, most single-cycle |
| ADC Resolution | 10-bit |
| ADC Channels | 8 |
| Timer/Counters | 3 (two 8-bit, one 16-bit) |
| Package | 32-TQFP (7x7 mm) |
| Mounting Type | Surface Mount |
| Operating Temperature | -40 C to +85 C (industrial) |
| Flash Write/Erase Cycles | 10,000 |
| EEPROM Write Cycles | 100,000 |
| RoHS Status | Compliant |
ATMEGA48PA-AU Pin Configuration
| Pin 1 | PD3 β Port D bit 3 / INT1 / OC2B |
| Pin 2 | PD4 β Port D bit 4 / T0 / XCK |
| Pin 3 | GND β Ground |
| Pin 4 | VCC β Digital supply voltage |
| Pin 5 | GND β Ground |
| Pin 6 | VCC β Digital supply voltage |
| Pin 7 | PB6 β Port B bit 6 / XTAL1 / TOSC1 |
| Pin 8 | PB7 β Port B bit 7 / XTAL2 / TOSC2 |
| Pin 9 | PD5 β Port D bit 5 / T1 / OC0B |
| Pin 10 | PD6 β Port D bit 6 / AIN0 / OC0A |
| Pin 11 | PD7 β Port D bit 7 / AIN1 |
| Pin 12 | PB0 β Port B bit 0 / ICP1 / CLKO |
| Pin 13 | PB1 β Port B bit 1 / OC1A |
| Pin 14 | PB2 β Port B bit 2 / SS / OC1B |
| Pin 15 | PB3 β Port B bit 3 / MOSI / OC2A |
| Pin 16 | PB4 β Port B bit 4 / MISO |
| Pin 17 | PB5 β Port B bit 5 / SCK |
| Pin 18 | AVCC β Analog supply voltage for ADC |
| Pin 19 | ADC6 β Analog input channel 6 |
| Pin 20 | AREF β Analog reference voltage |
| Pin 21 | GND β Ground |
| Pin 22 | ADC7 β Analog input channel 7 |
| Pin 23 | PC0 β Port C bit 0 / ADC0 |
| Pin 24 | PC1 β Port C bit 1 / ADC1 |
| Pin 25 | PC2 β Port C bit 2 / ADC2 |
| Pin 26 | PC3 β Port C bit 3 / ADC3 |
| Pin 27 | PC4 β Port C bit 4 / ADC4 / SDA |
| Pin 28 | PC5 β Port C bit 5 / ADC5 / SCL |
| Pin 29 | PC6 β Port C bit 6 / RESET |
| Pin 30 | PD0 β Port D bit 0 / RXD |
| Pin 31 | PD1 β Port D bit 1 / TXD |
| Pin 32 | PD2 β Port D bit 2 / INT0 |
Typical Applications
ATMEGA48PA-AU is suitable for 6 applications: Industrial Control Panels, Battery-Powered Sensor Nodes, Consumer Appliance Control, Low-Power IoT Edge Nodes, Portable Medical Instruments, Automotive Aftermarket Modules.
Industrial Control Panels
The ATMEGA48PA-AU fits industrial control panels because its 23 I/O lines, three timer/counters, and 10-bit ADC can directly drive relays, read limit switches, and sample analog sensors without external glue logic. Running at 20 MHz from a 5 V rail, it executes control loops deterministically with single-cycle instruction throughput. The 4 KB Flash is sufficient for ladder-logic emulation, Modbus RTU slave stacks, and menu-driven HMI firmware. A typical implementation places the MCU behind an opto-isolated RS-485 transceiver, using the 16-bit Timer1 for baud-rate generation and the watchdog for fail-safe recovery. The trade-off is limited SRAM: 512 bytes constrains buffer depth, so designs should stream data rather than queue it. The -40 C to +85 C industrial temperature rating supports factory-floor environments.
Recommended
Battery-Powered Sensor Nodes
The ATMEGA48PA-AU is well suited to battery-powered sensor nodes because picoPower technology keeps power-down current in the sub-microamp range and the 1.8 V minimum supply allows direct operation from two AA cells. In a typical duty-cycled design the MCU wakes from power-save mode on a Timer2 overflow, samples a thermistor or bridge sensor through the 8-channel 10-bit ADC, averages the reading in SRAM, and transmits over a UART or SPI radio before returning to sleep. The internal calibrated RC oscillator removes the external crystal, cutting BOM cost and board area. The trade-off is that 4 KB Flash limits protocol stack complexity, so lightweight proprietary framing is preferred over full TCP/IP. Estimated average current in a 1% duty cycle at 1 MHz is in the tens of microamps.
Recommended
Consumer Appliance Control
The ATMEGA48PA-AU is widely used in consumer appliance control because it integrates the ADC, timers, and PWM outputs needed for touch buttons, motor triac firing, and temperature sensing on a single 32-pin device. Three timer/counters generate the PWM used for fan speed and heater duty-cycle control, while the 10-bit ADC reads NTC thermistors and capacitive touch pads through a simple RC network. The 4 KB Flash accommodates state-machine firmware for wash cycles, cooking profiles, or charge sequences. Operating from a 5 V rail, the device drives LEDs and relays through external transistors. The main design consideration is noise: keep the analog AVCC pin decoupled with a 100 nF capacitor and route motor return currents away from the MCU ground to protect ADC accuracy.
Recommended
Low-Power IoT Edge Nodes
The ATMEGA48PA-AU serves low-power IoT edge nodes where deterministic real-time response and long battery life outweigh high throughput. Its AVR core executes most instructions in one clock cycle, so a 20 MHz clock delivers predictable latency for interrupt-driven sensor sampling, while multiple sleep modes reduce average current to microamp levels between transmissions. The 23 I/O lines connect directly to SPI LoRa or sub-GHz radio modules, and the hardware UART handles AT-command framing. With only 4 KB Flash, the firmware must be lean: a sensor driver, a compact MAC layer, and a wake-schedule state machine fit comfortably, but full TLS stacks do not. Pairing the MCU with an external radio and using the watchdog timer for recovery yields a robust, low-cost edge node.
Recommended
Portable Medical Instruments
The ATMEGA48PA-AU suits portable medical instruments such as glucose meters, digital thermometers, and pulse oximeter front ends because its 10-bit ADC and low-noise analog supply pins support accurate sensor digitization at low cost. The device runs from 1.8 V to 5.5 V, allowing direct operation from a single Li-ion cell, and its picoPower sleep modes extend battery life between measurements. Firmware typically sequences an analog front-end amplifier, averages multiple ADC samples to reduce noise, applies a calibration polynomial stored in the 256-byte EEPROM, and displays results on a small segment LCD driven by I/O pins. The 4 KB Flash is adequate for measurement, calibration, and display routines. Designers should decouple AVCC separately and use the internal bandgap reference for ratiometric measurements.
Recommended
Automotive Aftermarket Modules
The ATMEGA48PA-AU is used in automotive aftermarket modules such as LED controllers, window-rollup timers, and CAN-gateway adapters where a compact, low-cost 8-bit controller is sufficient. Its 23 I/O lines drive MOSFET gates for lighting PWM, read switch inputs, and interface to CAN or LIN transceivers through the hardware UART and SPI. The 16-bit Timer1 provides precise PWM timing for LED dimming without visible flicker, and the watchdog timer ensures recovery from transient electrical noise. The industrial -40 C to +85 C rating covers most cabin and aftermarket environments, though under-hood designs should verify thermal margins. The main consideration is supply protection: add reverse-polarity and load-dump clamping ahead of the 5 V regulator to protect the MCU in 12 V automotive rails.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA48PA-AU β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA88PA-AU | ATMEGA168PA-AU | ATMEGA328P-AU | ATMEGA48-20AU |
|---|---|---|---|---|---|
| Package | 32-TQFP (7x7 mm) | 32-TQFP (7x7 mm) - same | 32-TQFP (7x7 mm) - same | 32-TQFP (7x7 mm) - same | 32-TQFP (7x7 mm) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 4 KB | 8 KB | 16 KB | 32 KB | 4 KB |
| SRAM | 512 B | 1 KB | 1 KB | 2 KB | 512 B |
| EEPROM | 256 B | 512 B | 512 B | 1 KB | 256 B |
| Maximum Clock Frequency | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| Operating Voltage | 1.8 V to 5.5 V | 1.8 V to 5.5 V | 1.8 V to 5.5 V | 1.8 V to 5.5 V | 2.7 V to 5.5 V |
| I/O Lines | 23 | 23 | 23 | 23 | 23 |
| Power-Down Current | picoPower (sub-1 uA typical) | picoPower (sub-1 uA typical) | picoPower (sub-1 uA typical) | picoPower (sub-1 uA typical) | Higher standby current (non-picoPower) |
| ADC | 10-bit, 8 channels | 10-bit, 8 channels | 10-bit, 8 channels | 10-bit, 8 channels | 10-bit, 8 channels |
Key Differentiators
- Lowest-cost entry point in the 32-pin AVR family (vs ATMEGA328P-AU)
- picoPower low-power operation (vs ATMEGA48-20AU)
- Pin-compatible memory scaling path (vs ATMEGA88PA-AU)
- Integrated analog and timing peripherals (vs ATMEGA48PA-AN)
Design Notes
Decouple every VCC pin (pins 4 and 6) with a 100 nF ceramic capacitor placed within a few millimeters of the pin, and add a 10 uF bulk capacitor on the board rail. Decouple AVCC (pin 18) separately through a 100 nF capacitor plus a series ferrite bead to isolate ADC noise from the digital supply. If the ADC is unused, AVCC must still be connected to VCC. Estimated: at 20 MHz and 5 V, core current is on the order of 10-15 mA, so a 100 nF per-pin decoupling network keeps supply ripple well below the ADC LSB.
Keep the crystal or resonator loop between XTAL1 (pin 7) and XTAL2 (pin 8) as short as possible, with the load capacitors returned to a local ground plane directly under the device. Route the RESET line (pin 29) away from switching nodes and add a 100 nF capacitor to ground near the pin to prevent noise-induced resets. Place the ISP programming header close to the MCU so MOSI, MISO, SCK, and RESET traces stay short during in-system programming.
Do not leave AREF (pin 20) floating when the ADC is used; connect it to AVCC through a 100 nF capacitor or to an external reference. The internal 8 MHz RC oscillator is factory-calibrated but has several percent frequency tolerance, so use an external crystal when UART baud accuracy or timer precision matters. Also verify that the brown-out detector level is set appropriately for the supply ramp; a slow-rising rail can cause unreliable startup if BOD is disabled.
The 32-TQFP package has low power dissipation at typical operating currents, so no heatsink is required. Estimated: at 5 V and 15 mA the device dissipates roughly 75 mW, giving a junction rise of only a few degrees Celsius above ambient in still air. Ensure the exposed thermal path through the PCB copper is adequate if the device is placed near other heat sources such as linear regulators or power MOSFETs.
Compliance Information
The ATMEGA48PA-AU is RoHS compliant and lead-free per distributor and manufacturer listings. It is not AEC-Q100 qualified; automotive-grade variants should be sourced separately. Halogen-free status is not stated in the verified data.
