ATMEGA8A-AN - 8-Bit AVR MCU 16MHz 8KB Flash | Microchip
MPN: ATMEGA8A-AN ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.35 | $2.35 |
| 10 | $2.12 | $21.20 |
| 100 | $1.89 | $189.00 |
| 500 | $1.72 | $860.00 |
| 1,000 | $1.58 | $1,580.00 |
ATMEGA8A-AN Overview
An 8-bit microcontroller is a single-chip computer that integrates a CPU, program memory (Flash), data memory (SRAM), non-volatile storage (EEPROM), and peripherals such as timers, serial interfaces, and analog-to-digital converters on one die. The AVR architecture is a modified Harvard RISC core that executes most instructions in a single clock cycle, giving the ATmega8A deterministic, low-latency response for real-time control. In the product hierarchy, the ATmega8A sits under 8-bit AVR microcontrollers, which belong to the broader microcontroller (MCU) family within embedded processing ICs.
Key features include 8 KB Flash with read-while-write capability, 512 B EEPROM for parameter storage, 1 KB SRAM, 23 programmable I/O lines, three flexible timer/counters with compare modes, an 8-channel 10-bit ADC, a programmable USART, and both SPI and TWI (I2C) serial interfaces. The device supports in-system programming (ISP) and a boot loader, enabling field firmware updates without removing the chip.
The ATmega8A is fabricated on Microchip's high-performance, low-power CMOS process and is pin-compatible with the original ATmega8, making it a direct replacement in existing designs. Its 16 MHz maximum clock at 4.5-5.5 V and 8 MHz at 2.7-4.5 V give designers a clear voltage-frequency trade-off for power-sensitive products.
Typical applications include motor control boards, USBasp programmer hardware, battery chargers, sensor nodes, and legacy industrial controllers. The 32-TQFP package with 0.8 mm pitch suits automated SMT assembly, and the 23 I/O lines provide enough headroom for keypad, display, and communication interfaces in compact designs.
When designing with the ATMEGA8A-AN, decouple VCC and AVCC with 100 nF ceramic capacitors placed close to the pins, and connect the AREF pin through a low-pass filter when using the ADC. Keep the reset pin pulled high through 10 kohm and provide an ISP header for programming.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet, giving engineers a single reference for selection, cross-referencing, and layout decisions.
Drop-in alternatives for ATMEGA8A-AN — 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-AN (same form factor and footprint) — differing in Operating Temperature, Package, Flash Memory, Timers/Counters, Core Architecture.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATMEGA8A-AU
✅ Drop-In✓ In Stock
$1.31 / Unit
View Datasheet →ATMEGA8A-AUR
✅ Drop-In📋 Reference alternative (not in catalog)
ATMEGA88PA-ANR
✅ Drop-In✓ In Stock
$0.92 / Unit
View Datasheet →ATMEGA88PA-AUR
✅ Drop-In✓ In Stock
$0.82 / Unit
View Datasheet →ATMEGA88A-AU
✅ Drop-In✓ In Stock
$1.52 / Unit
View Datasheet →ATMEGA168PA-AU
✅ Drop-In✓ In Stock
$0.98 / Unit
View Datasheet →ATMEGA8A-AN Maximum Ratings & Electrical Characteristics
| Core Architecture | 8-bit AVR RISC |
| Program Memory (Flash) | 8 KB (4K x 16) in-system programmable |
| EEPROM | 512 B |
| SRAM | 1 KB |
| Maximum Operating Frequency | 16 MHz |
| Throughput | Up to 16 MIPS at 16 MHz |
| Operating Voltage | 2.7 V to 5.5 V |
| General Purpose I/O Lines | 23 |
| General Purpose Working Registers | 32 |
| Timer/Counters | 3 (two 8-bit, one 16-bit) with compare modes |
| ADC | 8-channel, 10-bit successive approximation |
| Serial Interfaces | USART, SPI, TWI (I2C) |
| Package | 32-TQFP (7x7 mm) |
| Mounting Type | Surface Mount |
| Operating Temperature | -40C to +85C |
| Interrupts | Internal and external, 19 interrupt vectors |
| Programming | In-System Programming (ISP), boot loader support |
| RoHS Status | Compliant |
ATMEGA8A-AN Pin Configuration
| Pin 1 | PB0 — Port B bit 0 / ICP1 |
| Pin 2 | PB1 — Port B bit 1 / OC1A |
| Pin 3 | PB2 — Port B bit 2 / SS / OC1B |
| Pin 4 | PB3 — Port B bit 3 / MOSI / OC2 |
| Pin 5 | PB4 — Port B bit 4 / MISO |
| Pin 6 | PB5 — Port B bit 5 / SCK |
| Pin 7 | PB6 — Port B bit 6 / XTAL1 / TOSC1 |
| Pin 8 | PB7 — Port B bit 7 / XTAL2 / TOSC2 |
| Pin 9 | RESET — Reset input (active low) |
| Pin 10 | VCC — Digital supply voltage |
| Pin 11 | GND — Ground |
| Pin 12 | XTAL2 — Crystal oscillator output |
| Pin 13 | XTAL1 — Crystal oscillator input / external clock |
| Pin 14 | PD0 — Port D bit 0 / RXD |
| Pin 15 | PD1 — Port D bit 1 / TXD |
| Pin 16 | PD2 — Port D bit 2 / INT0 |
| Pin 17 | PD3 — Port D bit 3 / INT1 |
| Pin 18 | PD4 — Port D bit 4 / OC1B |
| Pin 19 | PD5 — Port D bit 5 / OC1A |
| Pin 20 | PD6 — Port D bit 6 / OC0 |
| Pin 21 | PD7 — Port D bit 7 |
| Pin 22 | PC0 — Port C bit 0 / ADC0 |
| Pin 23 | PC1 — Port C bit 1 / ADC1 |
| Pin 24 | PC2 — Port C bit 2 / ADC2 |
| Pin 25 | PC3 — Port C bit 3 / ADC3 |
| Pin 26 | PC4 — Port C bit 4 / ADC4 |
| Pin 27 | PC5 — Port C bit 5 / ADC5 |
| Pin 28 | PC6 — Port C bit 6 / RESET |
| Pin 29 | PC7 — Port C bit 7 |
| Pin 30 | AVCC — Analog supply voltage for ADC |
| Pin 31 | GND — Ground |
| Pin 32 | AREF — Analog reference voltage for ADC |
Typical Applications
ATMEGA8A-AN is suitable for 6 applications: Motor Control Boards, USBasp Programmer Hardware, Battery Chargers and Power Management, Industrial Sensor Nodes, Consumer Appliance Control, Educational and Prototyping Platforms.
Motor Control Boards
The ATMEGA8A-AN fits motor control boards because its three timer/counters with compare modes generate precise PWM signals for three-phase brushless DC and stepper motor drive. At 16 MHz it executes control loops in single clock cycles, giving deterministic commutation timing. The 8-channel 10-bit ADC samples current-sense shunts and Hall-effect sensors for closed-loop speed and torque regulation. Microchip's ATmega8A motor control reference designs use the 16-bit Timer1 in phase-correct PWM mode to drive six N-channel MOSFETs through a gate driver, while the USART reports telemetry to a host. The 23 I/O lines accommodate enable, fault, and direction signals without external port expanders. A trade-off is that the 8 KB Flash limits complex field-oriented control algorithms, so designers often use lookup-table commutation instead of full FOC math.
Recommended
USBasp Programmer Hardware
The ATMEGA8A-AN is the canonical microcontroller in USBasp programmer designs, where it implements a USB 1.1 low-speed software stack in firmware and drives the ISP interface for AVR target programming. Its 8 KB Flash holds the V-USB bit-banged USB stack plus the ISP protocol handler, while the 512 B EEPROM stores device configuration. The 23 I/O lines map directly to the ISP header (MOSI, MISO, SCK, RESET) and status LEDs. Running at 12 MHz from a crystal, the ATmega8A meets USB low-speed timing tolerances without external USB hardware. The main design consideration is that the software USB stack consumes most of the CPU budget, leaving limited headroom for additional features; the 1 KB SRAM is adequate for USB endpoint buffers but not for large data logging.
Recommended
Battery Chargers and Power Management
The ATMEGA8A-AN suits battery charger designs because its 10-bit ADC monitors cell voltage and temperature while the timer/counters generate PWM for charge-current regulation. The 2.7-5.5 V operating range allows direct operation from a single Li-ion cell or a regulated 5 V rail, and the 23 I/O lines handle status LEDs, buttons, and a small LCD. In a typical topology, the ADC samples a resistor divider across the battery and an NTC thermistor, and firmware implements constant-current/constant-voltage (CC/CV) charging by adjusting a PWM-driven pass element. The 512 B EEPROM stores charge profiles and cycle counters across power loss. A key trade-off is that the internal ADC reference is only accurate to a few percent, so precision chargers add an external reference or calibrate in production.
Recommended
Industrial Sensor Nodes
The ATMEGA8A-AN is well suited to industrial sensor nodes because its 8-channel 10-bit ADC and multiple serial interfaces (USART, SPI, TWI) connect directly to analog transducers and digital sensor ICs. The 16 MHz core processes filtering and linearization algorithms in real time, while the 512 B EEPROM retains calibration coefficients. In a typical node, the ADC samples a pressure or temperature bridge, firmware applies polynomial compensation, and the USART or TWI transmits results to a PLC or gateway. The -40C to +85C industrial temperature range covers most factory-floor environments. The main limitation is the 1 KB SRAM, which constrains buffer sizes for high-rate sampling; designers often average samples in firmware rather than storing long bursts.
Recommended
Consumer Appliance Control
The ATMEGA8A-AN is widely used in consumer appliance control because it integrates the CPU, Flash, EEPROM, timers, ADC, and serial interfaces needed for keypad scanning, display driving, and motor or heater control on a single 32-TQFP die. The 23 I/O lines directly drive LEDs and read membrane keypads, while the 16-bit timer generates AC phase-control or PWM outputs for heating elements and fan motors. The 2.7-5.5 V range supports both 3.3 V and 5 V logic rails, simplifying power architecture. Firmware in 8 KB Flash implements user interface state machines and safety interlocks, and the 512 B EEPROM stores user settings. A design consideration is that appliance safety standards require watchdog and brown-out detection, both of which the ATmega8A integrates on-chip.
Recommended
Educational and Prototyping Platforms
The ATMEGA8A-AN is a popular choice for educational and prototyping platforms because its AVR architecture is well documented, supported by free toolchains (AVR-GCC, Atmel Studio), and available in a solder-friendly 32-TQFP package. Students and hobbyists use it to learn embedded C programming, timer interrupts, ADC sampling, and serial communication on real hardware. The 8 KB Flash is large enough for teaching examples and small projects, and the ISP interface allows low-cost programming with a USBasp or Arduino-as-ISP. The 23 I/O lines support breadboard-friendly breakout boards. The main trade-off versus the ATmega328P is smaller memory, so complex Arduino libraries may not fit; however, the ATmega8A remains an excellent low-cost entry point for AVR education.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA8A-AN — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA8A-AU | ATMEGA88PA-ANR | ATMEGA168PA-AU |
|---|---|---|---|---|
| Package | 32-TQFP (7x7) | 32-TQFP (7x7) - same | 32-TQFP (7x7) - same | 32-TQFP (7x7) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 8 KB | 8 KB | 8 KB | 16 KB |
| SRAM | 1 KB | 1 KB | 1 KB | 1 KB |
| EEPROM | 512 B | 512 B | 512 B | 512 B |
| Maximum Frequency | 16 MHz | 16 MHz | 20 MHz | 20 MHz |
| Operating 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 |
| GPIO Lines | 23 | 23 | 23 | 23 |
| ADC Channels | 8-channel 10-bit | 8-channel 10-bit | 8-channel 10-bit | 8-channel 10-bit |
| Firmware Compatibility | ATmega8A register map | Identical - no recompile | Different register map - recompile required | Different register map - recompile required |
Key Differentiators
- Pin-compatible with original ATmega8 (vs ATMEGA88PA-ANR)
- Lower cost than higher-memory siblings (vs ATMEGA168PA-AU)
- Wide 2.7-5.5 V supply range (vs ATMEGA88PA-ANR)
Design Notes
Decouple both VCC (pin 10) and AVCC (pin 30) with 100 nF ceramic capacitors placed within 5 mm of the pins, and add a 10 uF bulk capacitor on the board rail. AVCC must be connected even when the ADC is unused. For ADC accuracy, insert a 10 ohm resistor and 100 nF capacitor low-pass filter between VCC and AVCC, and drive AREF from a clean reference or through a similar filter. Estimated: at 16 MHz and 5 V, core current is roughly 15 mA, so a 100 nF decoupling capacitor per supply pin is sufficient to supply transient switching currents.
Place the 16 MHz crystal and its two load capacitors (typically 22 pF) as close as possible to XTAL1 (pin 13) and XTAL2 (pin 12), with a solid ground guard ring around the oscillator loop. Keep crystal traces under 10 mm and away from switching signals such as PWM outputs. Route the ISP header (MOSI, MISO, SCK, RESET) with short traces and series resistors if the cable is long. Connect the exposed thermal pad area under the TQFP to ground with multiple vias to improve thermal and noise performance.
Do not leave the RESET pin floating; pull it high through a 10 kohm resistor to VCC and add a 100 nF capacitor to ground for noise immunity. Ensure the brown-out detector is enabled in the fuse settings for reliable operation during power ramps. When migrating firmware from ATmega8 to ATmega8A, verify fuse bit defaults because the ATmega8A ships with different factory fuse values. Estimated: at 5 V and 16 MHz the part draws about 15 mA active, so a small SOT-23 LDO rated for 100 mA provides adequate margin.
Compliance Information
RoHS and REACH compliance per Microchip product page. Not AEC-Q100 qualified; automotive designs should use AEC-Q100 graded AVR variants. Halogen-free status not stated in the provided data.
