ATMEGA48PA-PU - 8-bit AVR MCU 4KB Flash 20MHz DIP-28 | Microchip
MPN: ATMEGA48PA-PU β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.6 | $2.60 |
| 10 | $2.45 | $24.50 |
| 100 | $2.33 | $233.00 |
| 500 | $2.2 | $1,100.00 |
| 1,000 | $2.05 | $2,050.00 |
ATMEGA48PA-PU Overview
An 8-bit microcontroller is a single-chip computer whose CPU processes data 8 bits at a time. The AVR family sits within the broader microcontroller hierarchy: microcontroller unit (MCU) -> embedded processor -> integrated circuit. AVR MCUs use a Harvard architecture with separate program and data buses, allowing most of the 131 instructions to execute in a single clock cycle, which yields up to 20 MIPS throughput at 20 MHz.
Key features of the ATMEGA48PA include the picoPower technology for ultra-low sleep-mode currents, 23 general-purpose I/O lines, three flexible timer/counters with compare modes, a 10-bit ADC with 8 channels, a USART, an SPI interface, and a two-wire (I2C-compatible) serial interface. The device operates from 2.5V to 5.5V, supporting both 3.3V and 5V systems, and offers six software-selectable power-saving modes including Power-down at very low current.
Architecturally, the ATMEGA48PA pairs the AVR enhanced RISC core with 32 general-purpose working registers, all directly connected to the ALU, enabling single-cycle access that eliminates the accumulator bottleneck of conventional 8051-style cores. The picoPower AVRs are fabricated on a low-leakage process, and the PA suffix denotes the power-optimized variant of the ATmega48 family.
Typical applications include hobbyist and educational projects (Arduino-compatible breadboard designs), appliance control, simple industrial sensing nodes, LED lighting controllers, and low-cost embedded systems where through-hole soldering and easy prototyping in DIP form matter.
A key design consideration: at 5V the device can run at the full 20 MHz, but at 3.3V the maximum safe clock is approximately 13.3 MHz per the datasheet frequency-versus-voltage curve; plan a 16 MHz or 8 MHz crystal for 3V operation.
This page synthesizes distributor pricing, drop-in family alternatives (ATmega88PA/168PA/328P-PU share the same DIP-28 footprint), and practical design notes not found in a single manufacturer datasheet.
Drop-in alternatives for ATMEGA48PA-PU 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-PU (same form factor and footprint) β differing in EEPROM, SRAM, Timers, Package, Flash Program Memory.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATMEGA48A-PU
β Drop-Inπ Reference alternative (not in catalog)
ATMEGA88PA-PU
β Drop-Inπ Reference alternative (not in catalog)
ATMEGA168PA-PU
β Drop-Inβ In Stock
$1.86 / Unit
View Datasheet βATMEGA328P-PU
β Drop-Inβ In Stock
Contact for price
View Datasheet βATMEGA48-20PI
β Drop-Inβ In Stock
$0.98 / Unit
View Datasheet βATMEGA48PA-PU Maximum Ratings & Electrical Characteristics
| Core Architecture | AVR 8-bit RISC |
| Flash Program Memory | 4 KB (2K x 16) |
| EEPROM | 256 B |
| SRAM | 512 B |
| Maximum Clock Frequency | 20 MHz |
| Max MIPS Throughput | 20 MIPS at 20 MHz |
| Supply Voltage Range | 2.5 V to 5.5 V |
| General Purpose I/O | 23 lines |
| Timers | Two 8-bit + one 16-bit timer/counter |
| ADC | 10-bit, 8 channels |
| Serial Interfaces | USART, SPI, 2-wire (I2C-compatible) |
| Operating Temperature | -40C to +85C (industrial) |
| Package | 28-PDIP |
| Mounting Type | Through Hole |
| Programming Method | In-System Programmable (ISP) |
| RoHS Status | Compliant |
| Instructions | 131 instructions, most single-cycle |
ATMEGA48PA-PU Pin Configuration
| Pin 1 | PC6/RESET β Reset input or Port C bit 6 |
| Pin 2 | PD0/RXD β USART receive or Port D bit 0 |
| Pin 3 | PD1/TXD β USART transmit or Port D bit 1 |
| Pin 4 | PD2/INT0 β External interrupt 0 or Port D bit 2 |
| Pin 5 | PD3/INT1/OC2B β External interrupt 1 / Timer2 PWM or Port D bit 3 |
| Pin 6 | PD4/T0/XCK β Timer0 clock / USART external clock or Port D bit 4 |
| Pin 7 | VCC β Digital supply voltage (2.5V to 5.5V) |
| Pin 8 | GND β Ground |
| Pin 9 | PB6/XTAL1/TOSC1 β Crystal oscillator input or Port B bit 6 |
| Pin 10 | PB7/XTAL2/TOSC2 β Crystal oscillator output or Port B bit 7 |
| Pin 11 | PD5/T1/OC0B β Timer1 clock / Timer0 PWM or Port D bit 5 |
| Pin 12 | PD6/AIN0/OC0A β Analog comparator positive input / Timer0 PWM or Port D bit 6 |
| Pin 13 | PD7/AIN1/OC1A β Analog comparator negative input / Timer1 PWM or Port D bit 7 |
| Pin 14 | PB0/ICP1/CLKO β Timer1 input capture / clock output or Port B bit 0 |
| Pin 15 | PB1/OC1A β Timer1 PWM output or Port B bit 1 |
| Pin 16 | PB2/SS/OC1B β SPI slave select / Timer1 PWM or Port B bit 2 |
| Pin 17 | PB3/MOSI/OC2A β SPI Master Out Slave In / Timer2 PWM or Port B bit 3 |
| Pin 18 | PB4/MISO β SPI Master In Slave Out or Port B bit 4 |
| Pin 19 | PB5/SCK β SPI serial clock or Port B bit 5 |
| Pin 20 | AVCC β ADC supply voltage (connect to VCC through low-pass filter) |
| Pin 21 | AREF β ADC analog reference input (decouple to GND) |
| Pin 22 | GND β Ground |
| Pin 23 | PC0/ADC0 β ADC channel 0 or Port C bit 0 |
| Pin 24 | PC1/ADC1 β ADC channel 1 or Port C bit 1 |
| Pin 25 | PC2/ADC2 β ADC channel 2 or Port C bit 2 |
| Pin 26 | PC3/ADC3 β ADC channel 3 or Port C bit 3 |
| Pin 27 | PC4/ADC4/SDA β ADC channel 4 / two-wire data or Port C bit 4 |
| Pin 28 | PC5/ADC5/SCL β ADC channel 5 / two-wire clock or Port C bit 5 |
Typical Applications
ATMEGA48PA-PU is suitable for 6 applications: Hobbyist and Educational Prototyping, Battery-Powered Sensor Nodes, Appliance and White-Goods Control, LED Lighting Controllers, Industrial Sensor Interfacing and Data Logging, Simple Embedded Communication Nodes.
Hobbyist and Educational Prototyping
The ATMEGA48PA-PU is a staple of breadboard electronics education because its 0.1-inch PDIP package plugs directly into solderless breadboards without adapters. Its 4 KB Flash is sufficient for classic exercises such as LED sequencing, button debouncing, PWM motor control, and serial telemetry, while the 20 MHz clock and single-cycle RISC execution give students responsive, predictable timing. Programming requires only a low-cost USBasp ISP programmer connected to the SPI header (MOSI/MISO/SCK on pins 17-19). The same footprint accepts ATMEGA88PA-PU or ATMEGA328P-PU upgrades, so a learning board scales with skill level without redesign.
Recommended
Battery-Powered Sensor Nodes
The picoPower ATMEGA48PA excels in battery-operated sensing where sleep current dominates battery life. In Power-down mode with watchdog running, supply current is in the microamp range per the Microchip datasheet, letting a coin-cell node idle for years between periodic ADC samples. The 10-bit, 8-channel ADC reads temperature, humidity, or light sensors directly, and the two-wire interface talks to I2C sensors at 100-400 kHz. Designers should drive I/O pins to defined levels before sleeping (avoid floating inputs) and select the 2.7V brown-out threshold for 3V coin-cell rails. A 3.3V/8 MHz crystal configuration keeps operation safely inside the frequency-voltage envelope.
Recommended
Appliance and White-Goods Control
Low-cost appliance control panels - fan speed, temperature cut-offs, indicator LEDs, and membrane-key handling - map naturally onto the ATMEGA48PA-PU's 23 GPIO lines and three timer/counters. The 16-bit timer supports phase-correct PWM for triac or relay phase control, while the internal 8 MHz RC oscillator eliminates crystal cost in non-critical timing applications. The 4 KB Flash holds a full state-machine application with serial diagnostics via the USART. Its industrial -40C to +85C rating covers unventilated appliance interiors, and the DIP package simplifies field-repairable designs or low-volume through-hole assembly in service markets.
Recommended
LED Lighting Controllers
Dimming and color-mixing LED fixtures benefit from the ATMEGA48PA-PU's hardware PWM: the two 8-bit timers each provide two compare channels and the 16-bit timer adds high-resolution dimming up to roughly 16-bit effective resolution with dithering. Driving MOSFET gate drivers from PB0-PB5 keeps switching losses predictable, and the 5V DIP device tolerates noisy lighting environments better than 3.3V-only MCUs. The ADC monitors supply voltage and LED thermal feedback through an NTC channel, enabling thermal fold-back firmware. At 20 MHz, a 300 Hz PWM carrier with 8-bit resolution and serial DMX-like control protocols fits comfortably in 4 KB.
Recommended
Industrial Sensor Interfacing and Data Logging
The ATMEGA48PA-PU serves as a low-cost front-end converting analog transducer signals into digital data. Its 10-bit ADC with differential inputs and 1x/20x gain stages measures thermocouple-amplified or bridge signals, while the USART streams readings to a host at up to 115.2 kbps (at 20 MHz). The 256 B EEPROM stores calibration constants that survive power cycles, and the watchdog timer provides autonomous recovery in unmanned installations. For higher-channel-count or 24-bit precision requirements, pair it with external ADCs over SPI. Designers should route AVCC (pin 20) separately through an LC filter and tie AREF to a decoupled reference for best noise performance.
Recommended
Simple Embedded Communication Nodes
The built-in USART plus SPI and two-wire interfaces make the ATMEGA48PA-PU a practical protocol converter: RS-485 field devices to I2C sensors, SPI EEPROM expansion, or software-UART debug bridges. The 20 MHz clock divides cleanly for standard baud rates (up to 1 Mbps USART in double-speed mode per the datasheet), and pin-change interrupts on all 23 GPIO lines allow bit-banged protocols such as 1-Wire or DHT sensor timing. At 5V, logic levels interface directly with classic RS-485 transceivers. Firmware overhead for framing, CRC, and buffering typically stays under 2 KB, leaving comfortable margin in the 4 KB Flash.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA48PA-PU β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA48A-PU | ATMEGA88PA-PU | ATMEGA168PA-PU | ATMEGA328P-PU | ATMEGA48-20PI |
|---|---|---|---|---|---|---|
| Package | 28-PDIP | 28-PDIP - same | 28-PDIP - same | 28-PDIP - same | 28-PDIP - same | 28-PDIP - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 4 KB | 4 KB | 8 KB | 16 KB | 32 KB | 4 KB |
| SRAM | 512 B | 512 B | 1 KB | 1 KB | 2 KB | 512 B |
| EEPROM | 256 B | 256 B | 512 B | 512 B | 1 KB | 256 B |
| Max Clock Frequency | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| Supply Voltage Range | 2.5 V to 5.5 V | 2.7 V to 5.5 V | 2.5 V to 5.5 V | 2.5 V to 5.5 V | 1.8 V to 5.5 V | 4.5 V to 5.5 V |
| Low Power (picoPower) | Yes (PA variant) | No (standard power) | Yes (PA variant) | Yes (PA variant) | Yes (P variant) | No (older generation) |
| Pin Compatibility | 28-pin mega48/88/168/328 DIP footprint | Pin-to-pin compatible | Pin-to-pin compatible | Pin-to-pin compatible | Pin-to-pin compatible | Pin-to-pin compatible |
Key Differentiators
- picoPower sleep currents in through-hole DIP (vs ATMEGA48A-PU)
- Lowest cost within a scalable pin-compatible family (vs ATMEGA328P-PU)
- Wider low-voltage operation than the older ATmega48 (vs ATMEGA48-20PI)
Design Notes
Respect the frequency-versus-voltage curve: 20 MHz is safe only at 4.5-5.5V. At 3.3V, limit the clock to roughly 13.3 MHz per the Microchip datasheet; use a 16 MHz crystal only if you accept marginal timing or run at 5V. Connect AVCC (pin 20) to VCC through an LC filter (10 uH + 100 nF) even if the ADC is unused - the datasheet requires AVCC within 0.3V of VCC. Set the brown-out detector via fuses (4.3V for 5V rails, 2.7V for 3.3V) so EEPROM writes are never corrupted during brown-out.
Even in through-hole designs, keep a 100 nF ceramic decoupling capacitor within a few millimeters of VCC (pin 7) and another at AVCC (pin 20). Decouple AREF (pin 21) with 100 nF to GND and never use it as a general power output unless the REFS bits select external reference mode deliberately. The DIP-28 lead inductance is modest, but long breadboard wires on the ISP header (pins 17-19) commonly cause SPI programming failures above 1 MHz SCK - slow the programmer clock if programming is unreliable.
Default fuse settings run the device from the internal 8 MHz RC oscillator divided by 8 (1 MHz), which surprises engineers expecting 20 MHz - set CKOUT/CKSEL fuses for your crystal and disable CKDIV8. Pin 1 (RESET) must be held high via a 10k pull-up; enabling RSTDISBL disables ISP programming. If migrating to ATmega48PB as Microchip's drop-in replacement, note the datasheet cautions: pin 3 must not be actively driven when tied to GND, and pin 6 must not be actively driven when tied to VCC.
Estimated: worst-case dissipation is negligible for this MCU. At 5.5V with a typical active-mode current on the order of 0.2-0.3 mA per MHz (about 5-6 mA at 20 MHz, per datasheet family curves), power is roughly 30 mW - no heatsink or copper pour consideration applies. Thermal design effort should instead go to adjacent power components (regulators, LED drivers). This estimate uses datasheet family typical-current figures; verify against the electrical characteristics table for your exact clock and voltage configuration.
Compliance Information
RoHS compliance and lead-free construction per Microchip current-production packaging for ATmega48PA. REACH, halogen-free, and conflict-minerals declarations should be pulled from Microchip's official compliance certificate for the exact date code.
