ATMEGA48-20AU - 8-bit AVR MCU 20MHz 4KB Flash | Microchip
MPN: ATMEGA48-20AU ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.47 | $2.47 |
| 10 | $2.22 | $22.20 |
| 100 | $1.98 | $198.00 |
| 500 | $1.78 | $890.00 |
| 1,000 | $1.6 | $1,600.00 |
ATMEGA48-20AU Overview
A microcontroller (MCU) is a single-chip computer that integrates a processor core, memory, and peripherals such as timers, ADCs, and serial interfaces on one die. The ATmega48 belongs to the 8-bit AVR family of microcontrollers, a subcategory of embedded processors within the broader semiconductor hierarchy, and executes powerful instructions in a single clock cycle, achieving throughput approaching 1 MIPS per MHz.
Key features include the Advanced RISC architecture with 130 instructions, mostly single-cycle execution, 32 general-purpose working registers, and fully static operation. The device offers three flexible timer/counters with compare modes, an internal and external interrupt system, a 6-channel 10-bit ADC in TQFP packages, a byte-oriented two-wire serial interface, an SPI serial port, a programmable serial USART, and an on-chip debug capability via debugWIRE.
The picoPower technology supports multiple sleep modes, including idle, ADC noise reduction, power-save, power-down, standby, and extended standby, enabling current consumption as low as microamp levels in power-down. The ATMEGA48-20AU is rated for 4.5V to 5.5V operation at 20 MHz (industrial grade), with in-system programmability through the SPI port allowing firmware updates on the finished PCB.
Typical applications include industrial control panels, home appliance control, sensor data acquisition nodes, low-cost motor control, and hobbyist/educational embedded systems where the mature AVR ecosystem, including AVR GCC toolchains and Arduino-compatible cores such as MiniCore, accelerates development.
When designing with this part, note that unlike the picoPower PA variants, this classic 20 MHz version targets 5V systems; for 1.8V-5.5V battery designs choose the ATMEGA48PA instead.
This page synthesizes distributor pricing, drop-in same-footprint alternatives across the ATmega48/88/168/328 family, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for ATMEGA48-20AU — 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 ATMEGA48-20AU (same form factor and footprint) — differing in Package, RoHS Status, EEPROM, Operating Temperature, SRAM.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATMEGA48-20AI
✅ Drop-In✓ In Stock
$0.82 / Unit
View Datasheet →ATMEGA48A-AU
✅ Drop-In ⚠️ 参数待验证📋 Reference alternative (not in catalog)
ATMEGA48PA-AU
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$1.38 / Unit
View Datasheet →ATMEGA88-20AU
✅ Drop-In📋 Reference alternative (not in catalog)
ATMEGA168-20AU
✅ Drop-In✓ In Stock
$1.82 / Unit
View Datasheet →ATMEGA328P-AU
✅ Drop-In✓ In Stock
$1.85 / Unit
View Datasheet →ATMEGA48-20AU Maximum Ratings & Electrical Characteristics
| Core Processor | AVR |
| Core Size | 8-Bit |
| Speed | 20 MHz |
| Flash Memory | 4 KB (2K x 16) |
| EEPROM | 256 B |
| SRAM | 512 B |
| Number of I/O | 23 |
| Operating Voltage | 4.5 V to 5.5 V |
| ADC Resolution | 10-bit |
| ADC Channels | 8 (6 external in TQFP package) |
| Timers/Counters | 3 (two 8-bit, one 16-bit) |
| Communication Interfaces | USART, SPI, I2C (Two-Wire) |
| Operating Temperature | -40C to +85C |
| Package | 32-TQFP (7x7 mm) |
| Mounting Type | Surface Mount |
| Program Memory Type | ISP Flash (In-System Programmable) |
| RoHS Status | Compliant |
ATMEGA48-20AU Pin Configuration
| Pin 1 | PD3 — Port D bit 3 (GPIO / INT1) |
| Pin 2 | PD4 — Port D bit 4 (GPIO / XCK/T0) |
| Pin 3 | GND — Ground |
| Pin 4 | VCC — Digital supply voltage |
| Pin 5 | GND — Ground |
| Pin 6 | VCC — Digital supply voltage |
| Pin 7 | PB6 — Port B bit 6 (XTAL1/TOSC1 - crystal input) |
| Pin 8 | PB7 — Port B bit 7 (XTAL2/TOSC2 - crystal output) |
| Pin 9 | PD5 — Port D bit 5 (GPIO / T1 / OC0B) |
| Pin 10 | PD6 — Port D bit 6 (GPIO / AIN0 / OC0A) |
| Pin 11 | PD7 — Port D bit 7 (GPIO / AIN1) |
| Pin 12 | PB0 — Port B bit 0 (GPIO / ICP1 / CLKO) |
| Pin 13 | PB1 — Port B bit 1 (GPIO / OC1A) |
| Pin 14 | PB2 — Port B bit 2 (GPIO / SS / OC1B) |
| Pin 15 | PB3 — Port B bit 3 (GPIO / MOSI / OC2A) |
| Pin 16 | PB4 — Port B bit 4 (GPIO / MISO) |
| Pin 17 | PB5 — Port B bit 5 (GPIO / SCK) |
| Pin 18 | AVCC — Analog supply voltage for ADC |
| Pin 19 | ADC6 — ADC input channel 6 |
| Pin 20 | AREF — Analog reference voltage |
| Pin 21 | GND — Ground |
| Pin 22 | ADC7 — ADC input channel 7 |
| Pin 23 | PC0 — Port C bit 0 (GPIO / ADC0 / SCL) |
| Pin 24 | PC1 — Port C bit 1 (GPIO / ADC1 / SDA) |
| Pin 25 | PC2 — Port C bit 2 (GPIO / ADC2) |
| Pin 26 | PC3 — Port C bit 3 (GPIO / ADC3) |
| Pin 27 | PC4 — Port C bit 4 (GPIO / ADC4 / SDA) |
| Pin 28 | PC5 — Port C bit 5 (GPIO / ADC5 / SCL) |
| Pin 29 | PC6 — Port C bit 6 (RESET - active low reset) |
| Pin 30 | PD0 — Port D bit 0 (GPIO / RXD) |
| Pin 31 | PD1 — Port D bit 1 (GPIO / TXD) |
| Pin 32 | PD2 — Port D bit 2 (GPIO / INT0) |
Typical Applications
ATMEGA48-20AU is suitable for 6 applications: Industrial Control and Automation, Home Appliance Control, Sensor Data Acquisition Nodes, Low-Cost Motor Control, Hobbyist and Educational Embedded Systems, Battery-Powered Portable Devices.
Industrial Control and Automation
The ATMEGA48-20AU fits industrial control nodes that need deterministic 8-bit control loops, multiple timers, and robust I/O. Its three timer/counters (two 8-bit, one 16-bit with compare and PWM modes) drive relay sequencing, motor PWM, and event timing, while the 10-bit ADC reads potentiometers, current shunts, and temperature sensors. The 4.5V-5.5V operating range tolerates noisy industrial 5V rails, and the -40C to +85C industrial temperature grade covers cabinet environments. Because the AVR executes most instructions in a single cycle at up to 20 MIPS, scan loops of a few microseconds are achievable. Use the watchdog timer and brown-out detector for fault recovery; in-system programming via SPI allows field firmware updates without desoldering the MCU, a key benefit for serviceable industrial equipment.
Recommended
Home Appliance Control
White-goods and small-appliance controllers benefit from the ATMEGA48-20AU's balance of cost, memory, and peripherals. A 4 KB Flash program typically holds button debounce, relay/SSR sequencing, buzzer tones, and ADC-based temperature monitoring (NTC via the 10-bit ADC) without overflowing. The internal RC oscillator allows crystal-less designs where timing accuracy is uncritical, reducing BOM cost, while the external 20 MHz crystal option supports precise PWM for induction or convection control. The picoPower sleep modes of the family enable low standby power for units always plugged into mains, and the brown-out detector prevents EEPROM corruption during brownouts. Its 23 I/O lines directly drive LED displays and seven-segment digits through the port registers with no external latch ICs needed.
Recommended
Sensor Data Acquisition Nodes
For wired sensor acquisition points, the ATMEGA48-20AU combines an 8-channel 10-bit ADC (6 external channels in TQFP), a differential-input programmable-gain stage, and the USART/SPI/two-wire interfaces needed to stream readings to a host. The ADC noise-reduction sleep mode quiets the digital core during conversions, improving effective resolution for bridge and thermistor inputs. AREF (pin 20) supports external precision references for ratio-metric measurements. At 20 MHz the device can sample and packetize several hundred conversions per second over UART at 115200 baud, sufficient for vibration, level, and environmental monitoring. The 512 B SRAM holds circular buffers for burst capture, and the 256 B EEPROM stores per-node calibration constants that survive power cycles without external memory.
Recommended
Low-Cost Motor Control
Small DC and stepper motor applications use the ATMEGA48-20AU's 16-bit Timer1 for four PWM outputs at up to 20 MHz resolution scaling, driving H-bridge and gate-driver inputs with constant-frequency, phase-correct, or fast-PWM modes. The input-capture unit timestamps quadrature or hall feedback edges in hardware, offloading the CPU for closed-loop speed control. Its single-cycle multiply (8x8 hardware multiplier) accelerates PI-loop arithmetic in fixed point. The 5V logic directly interfaces popular gate drivers without level shifting, and the 20 MHz clock gives 500 ns minimum PWM step for fine duty control. Protect the MCU with freewheeling diodes and separate analog ground; the ADC can monitor bus current through a shunt for stall detection and protection shutdown.
Recommended
Hobbyist and Educational Embedded Systems
The ATmega48 family is a staple of electronics education and maker projects because the AVR architecture is open, the toolchain (AVR-GCC, avrdude, MiniCore Arduino package) is free, and the 32-TQFP part is inexpensive as of 2026-09-18 at roughly $2.47 single quantity. Students learn registers, timers, interrupts, and ADCs directly without abstraction layers, then can scale to ATmega88/168/328 on the same PCB since the pinout is shared across the family. The debugWIRE interface permits single-wire on-chip debugging from Atmel Studio/Microchip Studio with only the RESET line, keeping breadboard layouts simple. DIP-adjacent breakout boards and countless tutorials make this part an ideal first microcontroller before moving to 32-bit ARM devices.
Recommended
Battery-Powered Portable Devices
For portable 5V or USB-powered instruments, the ATMEGA48-20AU's power management features minimize energy draw between measurements. Power-down mode stops the CPU and all clocks while retaining registers, with wake sources on pin-change interrupts, watchdog, and Timer2 asynchronous operation from a 32.768 kHz watch crystal in power-save mode for real-time keeping at microamp-scale current. The ADC noise-reduction mode yields cleaner conversions for battery gauging inputs. Note this classic 20 MHz part requires 4.5V-5.5V at full speed; designs using Li-ion cells (3.0V-4.2V) should select the ATMEGA48PA-AU drop-in variant, which meets voltage derating curves at reduced clock and cuts active current substantially. Firmware should exploit sleep between tasks to extend battery life.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA48-20AU — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA48-20AI | ATMEGA48A-AU | ATMEGA48PA-AU | ATMEGA88-20AU | ATMEGA168-20AU | ATMEGA328P-AU |
|---|---|---|---|---|---|---|---|
| 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 | 32-TQFP (7x7 mm) - same | 32-TQFP (7x7 mm) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | 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 Clock Speed | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| Operating Voltage | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 1.8 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 1.8 V to 5.5 V |
| Operating Temperature | -40C to +85C | -40C to +105C (automotive temp grade) | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C |
| picoPower Technology | No (classic core) | No | No | Yes | No | No | Yes |
Key Differentiators
- Lowest cost entry point in the pin-compatible family (vs ATMEGA328P-AU)
- Automotive temperature grade available in same footprint (vs ATMEGA48A-AU)
- Guaranteed 20 MHz operation specification (vs ATMEGA48PA-AU)
Design Notes
Estimated: with a 20 MHz crystal at 5V, active-mode current is roughly 8-10 mA typical per AVR family figures (verify against the current datasheet electrical characteristics table). Decouple both VCC pins (4 and 6) with 100 nF ceramic capacitors placed within 2 mm of each pin, plus one 4.7-10 uF bulk capacitor per board. Tie AVCC (pin 18) to VCC through a low-pass LC filter (10 uH + 100 nF + 100 nF) when ADC accuracy matters, and never leave AVCC floating even if the ADC is unused - the datasheet requires AVCC connected to VCC via an RC network for proper operation.
The 32-TQFP 0.8 mm pitch land pattern is shared across ATmega48/88/168/328, so lay out the footprint once and keep all port pins routed to 2.54 mm test headers for rework and in-circuit programming. Route the SPI ISP signals (MOSI, MISO, SCK, RESET on pins 15-17 and 29) to a standard 6-pin ISP header; this enables field updates and the debugWIRE single-wire debug on RESET. Keep the 20 MHz crystal (PB6/PB7, pins 7-8) within 10 mm of the MCU with 22 pF load capacitors and a ground guard ring to prevent jitter and startup failures.
Two frequent mistakes: (1) PC6 (pin 29) is the RESET pin, not a GPIO, unless the RSTDISBL fuse is programmed - doing so permanently disables ISP and debugWIRE, bricking the part for reprogramming, so avoid it in production. (2) Running 20 MHz below 4.5V violates the frequency-versus-voltage derating curve and causes unstable operation; if the supply is 3.3V, drop the clock to about 13.3 MHz or switch to the ATMEGA48PA variant. Also note the ATmega48 lacks a bootloader from the factory - an external ISP programmer is required for first-time programming.
Compliance Information
RoHS compliant per distributor listings (DigiKey/Mouser/LCSC). Halogen-free compliant per GlobalSpec cross-reference data. Not AEC-Q100 qualified; the -20AI variant offers extended temperature range but standard industrial qualification.
