ATMEGA48-20PI - AVR 8-Bit MCU 20MHz 4KB Flash 28-PDIP | Microchip
MPN: ATMEGA48-20PI β End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.85 | $1.85 |
| 10 | $1.66 | $16.60 |
| 100 | $1.42 | $142.00 |
| 500 | $1.21 | $605.00 |
| 1,000 | $0.98 | $980.00 |
ATMEGA48-20PI Overview
An 8-bit microcontroller (MCU) is a single integrated circuit that contains a processor core, program memory, data memory, and peripherals such as timers, ADCs, and communication interfaces. Within the power-management and embedded-system hierarchy, the MCU sits at the heart of every embedded application, reading sensors, executing control logic, and driving actuators. The ATMEGA48 belongs to the AVR ATmega family, which uses a modified Harvard RISC architecture that executes most of its 131 powerful instructions in a single clock cycle.
Key features include the AVR advanced RISC core with 32 general-purpose working registers, throughput of up to 20 MIPS at 20MHz, 1.8V to 5.5V wide supply operation, an 8-channel 10-bit ADC, debugWIRE on-chip debug system, and self-programming Flash program memory with 512-byte SRAM and 256-byte EEPROM for non-volatile data storage.
Technically, the ATMEGA48 combines a fast single-cycle ALU with pipelined instruction fetch, achieving one MIPS per MHz. Its two-cycle hardware multiplier, three flexible timers (two 8-bit, one 16-bit with PWM), USART, SPI, and two-wire I2C (TWI) interfaces make it a complete system-on-chip for compact control tasks. In-System Programming (ISP) allows firmware updates without removing the device from the PCB.
Typical applications include industrial automation and sensor nodes, home appliance control, hobby and educational projects such as Arduino-compatible boards (MiniCore supports the ATmega48), and battery-powered instruments where the 1.8V operation and low-power modes extend battery life.
When designing with the ATMEGA48-20PI, note that full 20MHz speed is guaranteed only at 4.5V to 5.5V; at lower supply voltages the maximum clock frequency must be derated per the datasheet frequency-versus-voltage curve.
This page synthesizes distributor pricing, drop-in alternatives, pinout data, and practical design notes not found in the manufacturer datasheet alone.
Drop-in alternatives for ATMEGA48-20PI 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 ATMEGA48-20PI (same form factor and footprint) β differing in Timers, EEPROM, SRAM, RoHS Status, Mounting Type.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATMEGA48-20PU
β Drop-Inπ Reference alternative (not in catalog)
ATMEGA48A-PU
β Drop-In β οΈ εζ°εΎ ιͺθ―β In Stock
$0.78 / Unit
View Datasheet βATMEGA48PA-PU
β Drop-In β οΈ εζ°εΎ ιͺθ―β In Stock
$2.05 / Unit
View Datasheet βATMEGA88-20PI
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA168-20PI
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA328P-PU
β Drop-In β οΈ εζ°εΎ ιͺθ―β In Stock
Contact for price
View Datasheet βATMEGA48-20PI Maximum Ratings & Electrical Characteristics
| Core Processor | AVR |
| Core Size | 8-Bit |
| Speed | 20 MHz |
| Program Flash Memory | 4 KB (2K x 16) |
| SRAM | 512 x 8 B |
| EEPROM | 256 x 8 B |
| Supply Voltage (Vcc/Vdd) | 2.7 V to 5.5 V (1.8 V to 5.5 V family range) |
| ADC Resolution | 10 bit |
| ADC Channels | 8 |
| Connectivity | I2C, SPI, UART/USART |
| Timers | Two 8-bit, one 16-bit |
| Operating Temperature | -40C to +85C (Industrial, I grade) |
| Package / Case | 28-PDIP (0.300 inch, 7.62 mm) |
| Mounting Type | Through Hole |
| MIPS Throughput | Up to 20 MIPS at 20 MHz |
| On-Chip Debug | debugWIRE |
| Series | AVR ATmega |
ATMEGA48-20PI Pin Configuration
| Pin 1 | PC6 (RESET) β Reset input / PCINT14; active-low with internal pull-up |
| Pin 2 | PD0 (RXD) β Port D bit 0 / USART receive input; PCINT16 |
| Pin 3 | PD1 (TXD) β Port D bit 1 / USART transmit output; PCINT17 |
| Pin 4 | PD2 (INT0) β Port D bit 2 / External interrupt 0; PCINT18 |
| Pin 5 | PD3 (INT1/OC2B) β Port D bit 3 / External interrupt 1, Timer2 PWM output; PCINT19 |
| Pin 6 | PD4 (T0/XCK) β Port D bit 4 / Timer0 external clock, USART external clock; PCINT20 |
| Pin 7 | VCC β Digital supply voltage (2.7V to 5.5V) |
| Pin 8 | GND β Ground |
| Pin 9 | PB6 (XTAL1/TOSC1) β Crystal oscillator input 1 / Timer oscillator; PCINT6 |
| Pin 10 | PB7 (XTAL2/TOSC2) β Crystal oscillator output 2 / Timer oscillator; PCINT7 |
| Pin 11 | PD5 (T1/OC0B) β Port D bit 5 / Timer1 external clock, Timer0 PWM output B; PCINT21 |
| Pin 12 | PD6 (AIN0/OC0A) β Port D bit 6 / Analog comparator positive input, Timer0 PWM output A; PCINT22 |
| Pin 13 | PD7 (AIN1) β Port D bit 7 / Analog comparator negative input; PCINT23 |
| Pin 14 | PB0 (ICP1/CLKO) β Port B bit 0 / Timer1 input capture, system clock output; PCINT0 |
| Pin 15 | PB1 (OC1A) β Port B bit 1 / Timer1 PWM output A; PCINT1 |
| Pin 16 | PB2 (SS/OC1B) β Port B bit 2 / SPI slave select, Timer1 PWM output B; PCINT2 |
| Pin 17 | PB3 (MOSI/OC2A) β Port B bit 3 / SPI master output, Timer2 PWM output A; PCINT3 |
| Pin 18 | PB4 (MISO) β Port B bit 4 / SPI master input; PCINT4 |
| Pin 19 | PB5 (SCK) β Port B bit 5 / SPI serial clock, also ISP programming clock; PCINT5 |
| Pin 20 | AVCC β ADC supply voltage; connect to VCC through low-pass filter |
| Pin 21 | AREF β ADC analog reference voltage |
| Pin 22 | GND β Ground |
| Pin 23 | PC0 (ADC0) β Port C bit 0 / ADC input channel 0; PCINT8 |
| Pin 24 | PC1 (ADC1) β Port C bit 1 / ADC input channel 1; PCINT9 |
| Pin 25 | PC2 (ADC2) β Port C bit 2 / ADC input channel 2; PCINT10 |
| Pin 26 | PC3 (ADC3) β Port C bit 3 / ADC input channel 3; PCINT11 |
| Pin 27 | PC4 (ADC4/SDA) β Port C bit 4 / ADC channel 4, TWI data line; PCINT12 |
| Pin 28 | PC5 (ADC5/SCL) β Port C bit 5 / ADC channel 5, TWI clock line; PCINT13 |
Typical Applications
ATMEGA48-20PI is suitable for 6 applications: Industrial Automation and Sensor Nodes, Home Appliance Control, Educational and Hobby Electronics, Battery-Powered Portable Instruments, Motor Control and PWM Systems, Embedded Communication Interfaces.
Industrial Automation and Sensor Nodes
The ATMEGA48-20PI fits industrial sensor nodes and small control modules because its industrial -40C to +85C temperature grade and 2.7V-5.5V supply tolerance match typical 5V or 3.3V factory rails. The 8-channel 10-bit ADC digitizes up to eight analog sensors (thermistors, pressure bridges, potentiometers) without an external converter, while the USART, SPI, and TWI (I2C) interfaces link to displays, EEPROMs, and higher-level PLC controllers. In a typical node the MCU samples sensors at a few hundred Hz, filters data using the 512B SRAM, and streams results over UART or RS-485 via an external transceiver. Its 20 MIPS core easily handles PID loops for simple actuators, and the watchdog timer plus brown-out detection provide the fault recovery industrial environments demand, with no external supervisor IC required.
Recommended
Home Appliance Control
White goods, coffee machines, fan controllers, and thermostats use the ATMEGA48-20PI as a low-cost main controller. The 4KB Flash is sufficient for state machines, button debouncing, relay sequencing, and simple UI logic driving 7-segment or LCD displays over SPI/I2C. The 256B EEPROM stores user settings and calibration values that survive power cycles, and the 10-bit ADC reads NTC temperature sensors with adequate resolution for comfort-control loops (Β±1C class accuracy). PWM outputs from the 16-bit Timer1 drive triac or transistor-based heater and motor power stages. The through-hole PDIP package simplifies low-cost single-sided PCB assembly for appliance makers, and the wide 1.8V-5.5V family voltage range tolerates unregulated supply rails during mains sags, improving field robustness.
Recommended
Educational and Hobby Electronics
The ATMEGA48-20PI is a favorite for universities, makerspaces, and hobby projects because the 28-PDIP package is socketable and breadboard-friendly, letting students swap chips without soldering. The MiniCore Arduino hardware package (open-source on GitHub) brings Arduino IDE support to the ATmega48, covering ATmega8 through ATmega328PB, so learners can use familiar digitalWrite/Serial APIs and a USBasp ISP programmer. With 20 MIPS throughput, the chip handles LED matrices, servo control, infrared remote decoding, and small robots. A minimum working system needs only a crystal, two 22pF caps, a 10k reset pull-up, and decoupling capacitors - a true 5-component Arduino-class platform. The identical pinout across ATmega48/88/168/328 lets one breadboard design scale with project complexity.
Recommended
Battery-Powered Portable Instruments
Handheld meters, data loggers, and remote controls benefit from the ATMEGA48 family's low-power modes and 1.8V operation. In power-down mode the ATmega48 draws microamp-level current, and the picoPower ATMEGA48PA revision extends this below 0.1 uA, enabling multi-year coin-cell life in datalogger designs. The 8-channel ADC samples external sensors on demand, the Timer/Counters generate periodic wake events, and the 256B EEPROM buffers calibration or log indexes. A typical design runs the MCU from 3V (two AA cells or a CR2032), wakes every second, takes one ADC reading into 512B SRAM, and writes daily summaries over SPI to an external Flash chip. Designers must derate clock speed at low voltage per the datasheet frequency-versus-voltage curve - at 1.8V, maximum clock is roughly 4MHz.
Recommended
Motor Control and PWM Systems
Small DC-motor and fan controllers exploit the ATMEGA48-20PI's three timers: two 8-bit timers for fast PWM at tens of kHz (inaudible fan control) and the 16-bit Timer1 for precise servo or phase-correct PWM. The ADC monitors current via a sense resistor and back-EMF or tachometer feedback on another channel, closing a speed loop in software at 20 MIPS with plenty of cycle margin for 4KB-scale code. Outputs drive MOSFET gate drivers or H-bridges; the MCU's USART accepts setpoint commands from a host while TWI daisy-chains multiple controllers on one bus. Built-in dead-time-safe software sequencing, brown-out protection preventing partial PWM states during power dips, and the watchdog timer make the design robust in cost-sensitive automotive accessory and appliance motor applications.
Recommended
Embedded Communication Interfaces
The ATMEGA48-20PI serves as a protocol bridge and front-end processor in embedded systems: its hardware USART (with UART/USART framing), SPI master/slave, and TWI (I2C-compatible) interfaces let it translate between RS-232/RS-485 links, SPI sensors, and I2C buses simultaneously. A common topology uses the 20MHz core to parse Modbus-RTU frames from the UART, read registers from I2C RTC and sensor chips, and expose configuration over SPI - all within the 4KB Flash budget. debugWIRE allows single-wire in-circuit debugging through the RESET pin during firmware development, shortening bring-up time. With 20 MIPS and single-cycle I/O access, bit-banged protocols for unusual peripherals (1-Wire, DHT sensors, software UART) also run reliably when hardware pins are exhausted.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA48-20PI β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA48-20PU | ATMEGA48A-PU | ATMEGA48PA-PU | ATMEGA88-20PI | ATMEGA168-20PI | ATMEGA328P-PU |
|---|---|---|---|---|---|---|---|
| Package | 28-PDIP (0.300 inch) | 28-PDIP (0.300 inch) - same | 28-PDIP (0.300 inch) - same | 28-PDIP (0.300 inch) - same | 28-PDIP (0.300 inch) - same | 28-PDIP (0.300 inch) - same | 28-PDIP (0.300 inch) - same |
| Brand | Atmel (Microchip Technology) | Atmel (Microchip Technology) | Microchip Technology | Microchip Technology | Atmel (Microchip Technology) | Atmel (Microchip Technology) | Microchip Technology |
| Flash Memory | 4 KB | 4 KB | 4 KB | 4 KB | 8 KB | 16 KB | 32 KB |
| SRAM | 512 B | 512 B | 512 B | 512 B | 1 KB | 1 KB | 2 KB |
| EEPROM | 256 B | 256 B | 256 B | 256 B | 512 B | 512 B | 1 KB |
| Max Speed | 20 MHz (20 MIPS) | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| Temperature Range | -40C to +85C (Industrial) | 0C to +70C (Commercial) | -40C to +85C | -40C to +85C | -40C to +85C (Industrial) | -40C to +85C (Industrial) | -40C to +85C |
| Supply Voltage | 2.7 V to 5.5 V | 2.7 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 | 2.7 V to 5.5 V | 1.8 V to 5.5 V |
| Lifecycle Status | EOL | EOL | Active | Active | EOL | EOL | Active |
Key Differentiators
- Industrial temperature range in PDIP (vs ATMEGA48-20PU)
- Lowest cost per function in the megaAVR PDIP family (vs ATMEGA328P-PU)
- Socket-friendly through-hole package (vs ATMEGA48-20AU (TQFP-32))
Design Notes
Respect the datasheet frequency-versus-voltage derating: the ATMEGA48-20PI guarantees 20MHz only at 4.5V to 5.5V. If you run from a 3.3V rail, limit the clock to roughly 13.3MHz (per the safe operating region in the Atmel datasheet); otherwise the device may miss timing or fail to start. Use AVCC within 0.3V of VCC and filter it with a 10uH inductor or ferrite bead plus 100nF when the ADC is used, to keep ADC noise below the 10-bit LSB level.
For the through-hole PDIP design, place a 100nF ceramic capacitor directly across VCC (pin 7) and GND (pin 8) within a few millimeters of the socket, plus a bulk 10uF near the power entry. Connect pin 22 (second GND) solidly to the ground plane - it serves the ADC ground return. Tie AVCC (pin 20) to VCC through an LC filter and decouple AREF (pin 21) with 100nF to GND; never leave AREF floating when using the ADC.
Fuse settings are the most common failure point when migrating between ATmega48 variants: the ATmega48 has no extended-bits boot section and uses different default clock fuses than the ATmega328P. When drop-in replacing with ATMEGA48A/48PA, re-verify CKSEL/SUT, BODLEVEL, and LOCK bits with the programmer - brown-out default levels differ between die revisions. Also remember debugWIRE disables external RESET; fuse-reset with a 12V-capable programmer is needed to recover. A socketed PDIP makes fuse recovery easy during prototyping.
Estimated: at 5V, 20MHz, and full peripheral activity, typical active current is roughly 5 mA, giving only 25 mW dissipation - junction rise above ambient is well under 1 C/W with the PDIP's theta_JA around 65 C/W, so no thermal management is ever required. Thermal concerns apply only to the surrounding power stage (drivers, regulators), not to the MCU itself.
Compliance Information
Compliance data not present in the provided web data. Verify RoHS/REACH status on the Microchip product page or with the seller; note the part is EOL and supplied via Rochester Electronics authorized specialty manufacturing.
