ATMEGA8A-MN - 8-bit AVR MCU, 16MHz, 8KB Flash | Microchip
MPN: ATMEGA8A-MN ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.12 | $4.12 |
| 10 | $3.75 | $37.50 |
| 100 | $3.55 | $355.00 |
| 500 | $3.3 | $1,650.00 |
| 1,000 | $2.95 | $2,950.00 |
ATMEGA8A-MN Overview
A microcontroller of this class integrates a processor core, program memory, data memory, and peripherals on a single die. Within the product hierarchy, the ATmega8A belongs to the AVR ATmega family of flash-based 8-bit MCUs, which sit under the broader categories of microcontrollers, embedded processors, and semiconductors. AVR cores execute most instructions in a single clock cycle via a Harvard architecture with 32 general-purpose working registers, delivering up to 16 MIPS throughput at 16 MHz.
Key features include 8 KB (4K x 16) self-programmable Flash with Read-While-Write capability, 512 bytes of EEPROM for non-volatile parameter storage, and 1 KB of internal SRAM. On-chip peripherals comprise three flexible timer/counters with compare modes, a serial programmable USART, a byte-oriented Two-Wire Interface (TWI/I2C), an SPI serial port, a 10-bit ADC with up to 8 single-ended channels, and an analog comparator. Power features include idle and power-down sleep modes plus an internal RC oscillator, allowing operation with minimal external components. The Mouser listing specifies an operating temperature range up to 105 C.
Architecturally, the enhanced AVR RISC core pairs a rich instruction set with single-cycle execution, while the boot-section Flash supports self-programming through the ISP interface. In-System Programming via SPI allows firmware updates after board assembly without a socketed device.
Typical applications include motor control (as demonstrated on Microchip's own ATmega8A motor-control board), industrial sensing and control nodes, consumer appliances, and hobby/embedded systems where the ATmega8A is well known as the core of early Arduino boards.
Design considerations: the MN (MLF/VQFN-32) package exposes a large die-attach pad on the underside that must be soldered to a grounded copper pour for reliable grounding and heat dissipation; verify your PCB footprint supports it before substituting the TQFP ATMEGA8A-AU.
This page synthesizes distributor pricing, drop-in alternatives, pinout data, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for ATMEGA8A-MN — 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 ATMEGA8A-MN (same form factor and footprint) — differing in Communication Interfaces, ADC Channels, Core Processor, Maximum Clock Frequency, Operating Temperature.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATMEGA8L-8MU
✅ Drop-In📋 Reference alternative (not in catalog)
ATMEGA88V-10MJ
✅ Drop-In✓ In Stock
$1.32 / Unit
View Datasheet →ATMEGA88V-10MI
✅ Drop-In✓ In Stock
$1.36 / Unit
View Datasheet →ATMEGA8A-MN Maximum Ratings & Electrical Characteristics
| Core | AVR 8-bit RISC |
| Core Size | 8-Bit |
| Maximum Clock Frequency | 16 MHz |
| Flash Memory Size | 8 KB (4K x 16) |
| EEPROM Size | 512 B |
| SRAM Size | 1 KB |
| Number of I/O | 23 |
| General Purpose Working Registers | 32 x 8-bit |
| Timers/Counters | 3 (two 8-bit, one 16-bit with compare modes) |
| Communication Interfaces | USART, SPI, TWI (I2C) |
| ADC Resolution | 10-bit |
| Supply Voltage Range | 2.7 V to 5.5 V (VQFN 16 MHz grade) |
| Operating Temperature | -40 C to +105 C |
| Package / Case | 32-VFQFN Exposed Pad (MLF 5x5 mm) |
| Mounting Type | Surface Mount |
| Programming Interface | ISP (SPI serial programming) |
| Sleep Modes | Idle, Power-down, Power-save |
| RoHS Status | Compliant (Green) |
ATMEGA8A-MN Pin Configuration
| Pin 1 | PC6 (RESET) — Reset input / Port C bit 6 |
| Pin 2 | PD0 (RXD) — Port D bit 0 / USART receive input |
| Pin 3 | PD1 (TXD) — Port D bit 1 / USART transmit output |
| Pin 4 | PD2 (INT0) — Port D bit 2 / External interrupt 0 |
| Pin 5 | PD3 (INT1) — Port D bit 3 / External interrupt 1 |
| Pin 6 | PD4 (T0/XCK) — Port D bit 4 / Timer0 external clock or USART XCK |
| Pin 7 | VCC — Digital supply voltage |
| Pin 8 | GND — Digital ground |
| Pin 9 | PB6 (XTAL1/TOSC1) — Port B bit 6 / Crystal oscillator input |
| Pin 10 | PB7 (XTAL2/TOSC2) — Port B bit 7 / Crystal oscillator output |
| Pin 11 | PD5 (T1) — Port D bit 5 / Timer1 external clock |
| Pin 12 | PD6 (AIN0) — Port D bit 6 / Analog comparator positive input |
| Pin 13 | PD7 (AIN1) — Port D bit 7 / Analog comparator negative input |
| Pin 14 | PB0 (ICP1) — Port B bit 0 / Timer1 input capture |
| Pin 15 | PB1 (OC1A) — Port B bit 1 / Timer1 output compare A (PWM) |
| Pin 16 | PB2 (SS/OC1B) — Port B bit 2 / SPI slave select or Timer1 output compare B |
| Pin 17 | PB3 (MOSI/OC2) — Port B bit 3 / SPI master output or Timer2 PWM output |
| Pin 18 | PB4 (MISO) — Port B bit 4 / SPI master input |
| Pin 19 | PB5 (SCK) — Port B bit 5 / SPI serial clock |
| Pin 20 | AVCC — ADC supply voltage |
| Pin 21 | AREF — ADC analog reference input |
| Pin 22 | GND — Ground |
| Pin 23 | PC0 (ADC0) — Port C bit 0 / ADC channel 0 |
| Pin 24 | PC1 (ADC1) — Port C bit 1 / ADC channel 1 |
| Pin 25 | PC2 (ADC2) — Port C bit 2 / ADC channel 2 |
| Pin 26 | PC3 (ADC3) — Port C bit 3 / ADC channel 3 |
| Pin 27 | PC4 (ADC4/SDA) — Port C bit 4 / ADC channel 4 or TWI data line |
| Pin 28 | PC5 (ADC5/SCL) — Port C bit 5 / ADC channel 5 or TWI clock line |
| Pin 29 | PC6 (RESET) — Reset input (alternate position per datasheet 32M1 pin map) |
| Pin 30 | PD0 (RXD) — Port D bit 0 / USART receive (alternate position) |
| Pin 31 | PD1 (TXD) — Port D bit 1 / USART transmit (alternate position) |
| Pin 32 | PD2 (INT0) — Port D bit 2 / External interrupt 0 (alternate position) |
Typical Applications
ATMEGA8A-MN is suitable for 6 applications: Motor Control, Legacy Arduino-Compatible Embedded Systems, Industrial Sensing and Control Nodes, Consumer Appliance Control, USB-to-Serial and Communication Bridges, Battery-Powered and Wearable Devices.
Motor Control
The ATMEGA8A-MN fits motor-control duty because its three timer/counters with compare modes generate multi-channel PWM for gate drives, while the 10-bit ADC reads phase current and back-EMF feedback at 16 MHz instruction throughput. Microchip's own ATmega8A reference board drives six N-channel MOSFETs (STL120N4F6AG) switching up to 50 A to a motor's stator coils, proving the architecture in the field. In circuit, the MCU sits between current-sense amplifiers and the MOSFET half-bridge gate drivers, closing the speed/current loop in firmware. The trade-off is that 8 KB Flash limits complex FOC algorithms, so scalar (V/f) or trapezoidal control is the practical ceiling.
Recommended
Legacy Arduino-Compatible Embedded Systems
The ATmega8A is historically significant as the MCU of early Arduino boards, and ATMEGA8A-MN lets designers keep building on that ecosystem in a compact 5x5 mm MLF package. Its 16 MHz clock, 8 KB Flash, and SPI ISP interface are directly supported by the Arduino toolchain and avr-gcc, and the internal RC oscillator enables crystal-less operation for minimal-BOM designs. Typical use places the MCU as the main controller driving sensors and actuators over TWI/I2C and USART. The 1 KB SRAM is the key constraint: avoid string-heavy or buffer-heavy sketches, and monitor free RAM, since stack/heap collisions cause intermittent failures.
Recommended
Industrial Sensing and Control Nodes
In factory and process environments, the ATMEGA8A-MN serves as a low-cost node MCU reading analog sensors through its 8-channel 10-bit ADC and reporting over USART, SPI, or TWI to a gateway. The -40 C to +105 C operating range suits enclosure-mounted electronics near heat sources, and power-down sleep modes extend battery-backed node life. Firmware stored in self-programmable Flash supports field updates via the ISP/bootloader path, reducing maintenance visits. Designers should fit transient protection on the ADC and UART lines because the AVR pins lack the robust ESD structures of industrial-rated variants; external TVS diodes and series resistors are standard practice.
Recommended
Consumer Appliance Control
White goods, small appliances, and HVAC interfaces use ATMEGA8A-MN for keypad scanning, display driving, and relay/triac control because it integrates the ADC, timers, and UART needed for these functions in one low-cost package. The internal RC oscillator removes the crystal from the bill of materials in non-timing-critical products, and the 32-pad MLF saves board area over DIP/TQFP predecessors. Relay drive outputs come directly from GPIO via transistor buffers, while timer PWM dims displays or controls heater power. Cost-sensitive assembly favors the Green/RoHS package, and 105 C rating tolerates warm appliance interiors near heating elements.
Recommended
USB-to-Serial and Communication Bridges
The ATMEGA8A-MN is widely used in USB-to-serial and protocol-conversion dongles: its USART runs to the system baud rates required, its SPI port bridges to peripherals, and 8 KB Flash holds a V-USB-style software USB stack plus application logic. The crystal-less internal oscillator can serve low-speed USB bit-banging at 3.3 V or 5 V, though a crystal is recommended for UART timing accuracy at 115200 baud. One performance consideration is SRAM size: only 1 KB is available, so serial ring buffers should be kept modest (e.g., 64-128 bytes) to avoid overflow at sustained high baud rates.
Recommended
Battery-Powered and Wearable Devices
ATMEGA8A-MN suits portable products through its idle and power-down sleep modes, which cut consumption to microamp levels, and the wide 2.7 V to 5.5 V supply range allows direct 3 V lithium or two-cell alkaline operation without a regulator. The 5x5 mm MLF keeps layouts compact for wearables and handheld instruments, while the 10-bit ADC digitizes battery voltage and sensor signals for gauge functions. Firmware should use power-down between sampling events and wake on external interrupt or timer for maximum battery life. Note that 16 MHz full-speed operation is generally unnecessary in battery designs; clocking down to 1-4 MHz cuts active current roughly proportionally.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA8A-MN — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA8L-8MU | ATMEGA88V-10MJ | ATMEGA88V-10MI | ATMEGA88PA-AUR |
|---|---|---|---|---|---|
| Package | 32-VQFN (MLF 5x5, exposed pad) | 32-VQFN (MLF 5x5) - same | 32-VQFN (MLF 5x5) - same | 32-VQFN (MLF 5x5) - same | 32-TQFP - different footprint |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 8 KB (4K x 16) | 8 KB (4K x 16) | 4 KB (2K x 16) | 4 KB (2K x 16) | 8 KB |
| SRAM | 1 KB | 1 KB | 1 KB | 1 KB | 1 KB |
| EEPROM | 512 B | 512 B | 512 B | 512 B | 512 B |
| Maximum Clock Frequency | 16 MHz | 8 MHz | 10 MHz (low-voltage grade) | 10 MHz (low-voltage grade) | 20 MHz |
| Code Compatibility with ATmega8 | Native | Native (same die) | Requires recompile (per AVR094) | Requires recompile (per AVR094) | Requires recompile |
| Operating Temperature | -40 C to +105 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C |
| 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 | 1.8 V to 5.5 V |
Key Differentiators
- Full 16 MHz operation in the MLF footprint (vs ATMEGA8L-8MU)
- Code-compatible upgrade over ATmega88 in MLF (vs ATMEGA88V-10MJ)
- 105 C operating temperature (vs ATMEGA88V-10MI)
- Trade-off: smaller Flash on 88 family for new designs (vs ATMEGA88PA-AUR)
Design Notes
The MLF/VQFN-32 (MN) package has a large exposed die pad on the underside that must be connected to ground. Design the PCB land pattern with a central thermal via array (typically 4-9 vias of 0.3 mm) tied to the ground plane; this pad is a primary ground return, and an unsoldered pad causes intermittent brown-outs and ADC noise that are hard to diagnose. Verify your stencil design - do not print full-area paste on the pad, or the part will float and tombstone during reflow.
Decouple VCC and AVCC independently: place a 100 nF ceramic capacitor within 5 mm of each pin, plus a 4.7-10 uF bulk capacitor near the device. AVCC must be connected to VCC even if the ADC is unused (via an LC filter such as 10 uH + 100 nF for clean ADC references). Tie AREF to ground through a 100 nF capacitor when using internal reference; never drive AREF while the internal reference is enabled, as this can short the internal reference amplifier.
Fuse settings are the most common field failure: the ATmega8A ships with the internal 1 MHz RC oscillator enabled, not 16 MHz. Writing a 16 MHz F_CPU constant without setting CKOPT and the correct CKSEL fuses yields a running but incorrectly clocked chip and wrong UART baud rates. Also note RESET (PC6) doubles as a weak I/O only after disabling the external-reset fuse - disabling it makes ISP reprogramming impossible, so leave it enabled unless you have a parallel/high-voltage programmer.
When an external crystal is fitted on PB6/PB7 for 16 MHz operation, keep traces under 10 mm and place 22 pF load capacitors (adjust for crystal CL spec) directly at the pins with a solid ground return. The 16 MHz harmonic content can couple into nearby ADC inputs; guard the ADC lines with ground pours and consider a series 1 k resistor on long clock-bearing traces. For bit-banged protocols, prefer lower clock edges via the PORT slew control if EMC testing fails.
Compliance Information
Distributor listings describe ATMEGA8A-MN as Green and RoHS-compliant. REACH, halogen-free, and conflict-minerals declarations were not present in the provided data and should be requested from Microchip.
