ATMEGA48-20AI - 8-bit AVR MCU, 4KB Flash, 20MHz | Microchip
MPN: ATMEGA48-20AI β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.62 | $1.62 |
| 10 | $1.45 | $14.50 |
| 100 | $1.18 | $118.00 |
| 500 | $0.98 | $490.00 |
| 1,000 | $0.82 | $820.00 |
ATMEGA48-20AI Overview
An 8-bit microcontroller is a single-chip processor that executes instructions, controls peripherals, and interfaces with sensors and actuators on a single silicon die. The ATMEGA48 belongs to the AVR family within the broader hierarchy of MCU -> embedded processor -> semiconductor, and integrates Flash program memory, SRAM data memory, EEPROM nonvolatile storage, and analog peripherals into one package, eliminating external memory chips in cost-sensitive embedded designs.
Key features include the AVR enhanced RISC core executing 131 powerful instructions, most in a single clock cycle; 1.8V to 5.5V operation; an 8-channel 10-bit ADC; and three flexible timer/counters. The 32 general purpose working registers are directly connected to the arithmetic logic unit, allowing one-cycle access that boosts effective throughput far beyond classic CISC MCUs at the same clock rate.
Technical depth: the ATMEGA48 supports self-programming Flash with an in-system programming (ISP) interface and includes debugWIRE, an on-chip debug system that uses only one pin, preserving I/O for the application. Peripherals include SPI and TWI (I2C-compatible) serial interfaces, a USART, analog comparator, and watchdog timer with its own oscillator.
Typical applications include consumer appliance control, industrial sensor nodes, motor control front-ends, and battery-powered devices that exploit the AVR picoPower-class sleep modes and 1.8V low-voltage operation.
Design consideration: the ATMEGA48-20AI is rated to 20MHz at 4.5V-5.5V; at lower supply voltages the maximum safe clock frequency derates, so verify the voltage-frequency curve in the datasheet before fixing the crystal.
This page synthesizes distributor availability, same-family drop-in alternatives, and practical design notes not consolidated in the manufacturer datasheet.
Drop-in alternatives for ATMEGA48-20AI 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 ATMEGA48-20AI (same form factor and footprint) β differing in EEPROM, Operating Temperature, Package, RoHS Status, SRAM.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATMEGA48-20AU
β Drop-Inβ In Stock
$1.6 / Unit
View Datasheet βATMEGA48P-20AU
β Drop-Inπ Reference alternative (not in catalog)
ATMEGA48V-10AU
β Drop-Inπ Reference alternative (not in catalog)
ATMEGA88-20AU
β Drop-Inπ Reference alternative (not in catalog)
ATMEGA168-20AU
β Drop-Inβ In Stock
$1.82 / Unit
View Datasheet βATMEGA48-20AI Maximum Ratings & Electrical Characteristics
| Core Architecture | AVR 8-bit RISC |
| Flash Program Memory | 4 KB (2K x 16), ISP self-programming |
| SRAM | 512 B |
| EEPROM | 256 B |
| Maximum CPU Speed | 20 MHz (up to 20 MIPS) |
| Supply Voltage Range | 1.8 V to 5.5 V |
| GPIO Count | 23 general purpose I/O lines |
| ADC | 8-channel, 10-bit |
| Timer/Counters | 3 (two 8-bit, one 16-bit) |
| Serial Interfaces | SPI, TWI (I2C-compatible), USART |
| On-Chip Debug | debugWIRE |
| Operating Temperature | -40C to +85C (Industrial) |
| Package | 32-TQFP, 7x7 mm, square, gull-wing leads |
| Mounting Type | Surface Mount |
| Temperature Grade | Industrial |
| RoHS Status | Green (per distributor data) |
ATMEGA48-20AI Pin Configuration
| Pin 1 | PD3 β Port D bit 3 (PCINT19/INT1/OC2B/ADC3) |
| Pin 2 | PD4 β Port D bit 4 (PCINT20/XCK/T0/ADC4) |
| 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 (PCINT6/XTAL1/TOSC1) |
| Pin 8 | PB7 β Port B bit 7 (PCINT7/XTAL2/TOSC2) |
| Pin 9 | PD5 β Port D bit 5 (PCINT21/OC0B/T1/ADC5) |
| Pin 10 | PD6 β Port D bit 6 (PCINT22/OC0A/AIN0/ADC6) |
| Pin 11 | PD7 β Port D bit 7 (PCINT23/AIN1) |
| Pin 12 | PB0 β Port B bit 0 (PCINT0/CLKO/ICP1) |
| Pin 13 | PB1 β Port B bit 1 (PCINT1/OC1A) |
| Pin 14 | PB2 β Port B bit 2 (PCINT2/SS/OC1B) |
| Pin 15 | PB3 β Port B bit 3 (PCINT3/MOSI/OC2A) |
| Pin 16 | PB4 β Port B bit 4 (PCINT4/MISO) |
| Pin 17 | PB5 β Port B bit 5 (PCINT5/SCK) |
| Pin 18 | AVCC β ADC supply voltage |
| Pin 19 | ADC6 β ADC input channel 6 |
| Pin 20 | AREF β Analog reference voltage |
| Pin 21 | GND β Ground |
| Pin 22 | ADC7 β ADC input channel 7 |
| Pin 23 | PC0 β Port C bit 0 (PCINT8/ADC0) |
| Pin 24 | PC1 β Port C bit 1 (PCINT9/ADC1) |
| Pin 25 | PC2 β Port C bit 2 (PCINT10/ADC2) |
| Pin 26 | PC3 β Port C bit 3 (PCINT11/ADC3) |
| Pin 27 | PC4 β Port C bit 4 (PCINT12/ADC4/SDA) |
| Pin 28 | PC5 β Port C bit 5 (PCINT13/ADC5/SCL) |
| Pin 29 | PC6 β Port C bit 6 (PCINT14/RESET) |
| Pin 30 | PD0 β Port D bit 0 (PCINT16/RXD) |
| Pin 31 | PD1 β Port D bit 1 (PCINT17/TXD) |
| Pin 32 | PD2 β Port D bit 2 (PCINT18/INT0) |
Typical Applications
ATMEGA48-20AI is suitable for 6 applications: Consumer Appliance Control, Industrial Sensor Nodes, Battery-Powered Portable Devices, Motor Control and PWM Drive, IoT and Smart Home Edge Nodes, Test and Measurement Accessories.
Consumer Appliance Control
The ATMEGA48-20AI fits appliance control boards such as coffee machines, fans, and small heaters where a low-cost MCU drives buttons, LEDs, and a triac or relay. Its 4KB Flash is sufficient for state machines, debounce logic, and PWM heater or motor control, while 23 GPIO lines cover keypad scanning and indicator multiplexing without port expanders. The 10-bit ADC reads NTC thermistors or user potentiometers with 8 selectable channels. Operating from a 5V linear rail, the 20MHz core leaves ample timing headroom for precise zero-cross switching via the external interrupt pins. Because the ATmega48/88/168 family shares one pinout, manufacturers can scale firmware between 4KB, 8KB, and 16KB SKUs on the same PCB, reducing qualification cost across product tiers.
Recommended
Industrial Sensor Nodes
In industrial sensing nodes, the ATMEGA48-20AI converts sensor signals through its 8-channel 10-bit ADC and streams results over SPI, TWI (I2C), or USART. The -40C to +85C industrial temperature rating matches factory-floor and outdoor cabinet environments where commercial-grade parts drift or fail. The 1.8V-5.5V supply range permits direct operation from 24V backplanes via a simple LDO without regulator redesign across platforms. Its watchdog timer with dedicated on-chip oscillator provides autonomous fault recovery in unattended installations, while debugWIRE allows field engineers to debug through a single wire on the populated board. The 20 MIPS throughput handles oversampling, averaging, and CRC-checked communication framing within the same 10ms sampling budget, keeping external glue logic to nearly zero.
Recommended
Battery-Powered Portable Devices
For battery-operated products such as handheld meters and remote controls, the ATMEGA48-20AI operates from 1.8V to 5.5V, spanning two alkaline cells through a Li-Ion cell without a boost converter. The AVR power management system offers idle, ADC noise reduction, power-save, power-down, and standby sleep modes, letting the MCU sleep between user events and wake on pin-change interrupts in microseconds. The 256B EEPROM stores calibration data and user settings through thousands of erase-write cycles, eliminating external nonvolatile memory. Where sleep current dominates the duty cycle, the pin-compatible ATMEGA48P-20AU picoPower variant drops standby consumption further while preserving the same 32-TQFP footprint and firmware portability. The 10-bit ADC and analog comparator support front-end measurements directly on-chip.
Recommended
Motor Control and PWM Drive
The ATMEGA48-20AI generates motor drive waveforms using its three flexible timer/counters: two 8-bit timers with two output-compare PWM channels each and one 16-bit timer for high-resolution PWM or input capture. At 20MHz, an 8-bit PWM achieves roughly 78kHz carrier frequency, comfortably above audible range for DC fan and small brushless motor control. The dead-time generation and output-compare pins drive half-bridge gate drivers through GPIO, while the 10-bit ADC monitors current via a shunt and the analog comparator provides fast over-current trip without CPU intervention. The 16-bit timer's input-capture unit measures tachometer periods for closed-loop speed regulation. With 23 GPIO lines, one ATMEGA48 can control multiple motors plus limit switches and status LEDs on a single low-cost TQFP-32 device.
Recommended
IoT and Smart Home Edge Nodes
Smart home nodes such as wall switches, thermostat add-ons, and RF module hosts use the ATMEGA48-20AI as a low-cost controller that bit-bangs or hardware-drives sub-GHz and 2.4GHz radio modules over SPI. The 20 MIPS throughput runs lightweight protocol stacks for sensor reporting, while the USART bridges to Wi-Fi or Zigbee modules. Sleep modes extend coin-cell and AA-battery life by remaining in power-down between transmissions, waking on radio IRQ via pin-change interrupts. The 4KB Flash accommodates application logic plus a minimal OTA-style bootloader in the self-programming Flash, enabling field firmware updates through TWI or SPI-attached external EEPROM. Designers retain an upgrade path: the identical pinout accepts ATMEGA88 or ATMEGA168 parts when feature growth demands more memory, with no PCB respin.
Recommended
Test and Measurement Accessories
Low-cost test accessories such as logic probes, dongle-style data loggers, and calibration adapters benefit from the ATMEGA48-20AI's deterministic single-cycle instruction execution, which produces predictable GPIO timing at the 20MHz core clock. debugWIRE enables real-time register and memory inspection through the RESET line on the assembled board, a significant advantage for verifying timing-critical firmware without dedicating pins to a JTAG port. The 10-bit ADC with internal reference digitizes battery voltage and probe status, while the USART reports streamed measurements to a PC at standard baud rates. The industrial temperature rating allows use in outdoor instrumentation enclosures. Because program memory is self-programmable, a host can update accessory firmware over the existing serial link, extending product life without hardware recalls or service interventions.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA48-20AI β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA48-20AU | ATMEGA48P-20AU | ATMEGA48V-10AU | ATMEGA88-20AU | ATMEGA168-20AU |
|---|---|---|---|---|---|---|
| Package | 32-TQFP (7x7) | 32-TQFP (7x7) - same | 32-TQFP (7x7) - same | 32-TQFP (7x7) - same | 32-TQFP (7x7) - same | 32-TQFP (7x7) - same |
| Brand | Microchip Technology (Atmel) | Microchip Technology (Atmel) | Microchip Technology (Atmel) | Microchip Technology (Atmel) | Microchip Technology (Atmel) | Microchip Technology (Atmel) |
| Flash Program Memory | 4 KB | 4 KB | 4 KB | 4 KB | 8 KB | 16 KB |
| SRAM | 512 B | 512 B | 512 B | 512 B | 1 KB | 1 KB |
| EEPROM | 256 B | 256 B | 256 B | 256 B | 512 B | 512 B |
| Maximum CPU Speed | 20 MHz | 20 MHz | 20 MHz | 10 MHz | 20 MHz | 20 MHz |
| Supply Voltage Range | 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 | 1.8 V to 5.5 V | 1.8 V to 5.5 V |
| Power Technology | Standard AVR power profile | Standard AVR power profile | picoPower (reduced sleep currents) | Low-voltage/low-speed profile | Standard AVR power profile | Standard AVR power profile |
Key Differentiators
- Lowest cost in the ATmega48/88/168 family (vs ATMEGA88-20AU)
- Full 20MHz speed rating (vs ATMEGA48V-10AU)
- Standard power profile availability (vs ATMEGA48P-20AU)
Design Notes
Decouple both VCC pins (4 and 6) and AVCC (pin 18) individually with 100nF ceramic capacitors placed within 5 mm of each pin, plus one 10uF bulk capacitor near the device. AVCC must be connected to VCC even if the ADC is unused, per the Atmel ATmega48/88/168 datasheet; when the ADC is active, filter AVCC through an LC network (10uH inductor with 100nF) to keep converter noise below the 10-bit LSB level. AREF should use an external 100nF capacitor to ground and never be driven while the internal reference is selected.
The 20MHz speed grade is guaranteed only near the top of the 4.5V-5.5V supply range; the datasheet maximum-frequency-versus-VCC curve derates the safe clock at lower voltages. Running a 20MHz crystal at 3.3V violates the derating curve and causes marginal, temperature-dependent failures. Also note PC6 doubles as active-low RESET: enabling debugWIRE frees it, but once fuse RSTDISBL is programmed, high-voltage parallel programming is the only recovery path. Verify fuse settings (CKDIV8, CKOUT) before flashing production units.
Keep the crystal or resonator on PB6/PB7 within 10 mm of the device with short, symmetrical traces and local ground return; route other signals away from the oscillator nets. The exposed TQFP lead frame needs no thermal pad, but use a solid ground plane under the part to contain ADC switching noise. For ISP programming, add the standard 6-pin (2x3, 2.54 mm) header on MOSI/MISO/SCK/RESET with 10k pull-up on RESET, ensuring downstream loads on RESET do not exceed the datasheet sink requirement during programming.
Compliance Information
Distributor data lists the part as GREEN (RoHS) packaging; REACH and conflict-minerals status should be confirmed on the Microchip compliance portal.
