ATMEGA8L-8AI - AVR 8-bit MCU 8MHz 8KB Flash 32-TQFP | Microchip
MPN: ATMEGA8L-8AI ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.2 | $3.20 |
| 10 | $2.85 | $28.50 |
| 100 | $2.4 | $240.00 |
| 500 | $2.05 | $1,025.00 |
| 1,000 | $1.75 | $1,750.00 |
ATMEGA8L-8AI Overview
An 8-bit AVR microcontroller is a Harvard-architecture RISC processor that executes most of its 130 instructions in a single clock cycle, delivering throughput approaching 1 MIPS per MHz. MCUs of this class sit at the entry level of the embedded microcontroller hierarchy and integrate CPU, program memory, data memory, timers, communication peripherals (SPI, TWI/I2C, UART), and analog-to-digital conversion on a single chip, replacing multi-chip solutions in cost-sensitive embedded control systems.
Key features include the 8KB in-system self-programmable Flash with 10,000 write-cycle endurance, on-chip 2.7V to 5.5V operation for battery-powered designs, and a rich peripheral set: three PWM channels, two 8-bit timers plus one 16-bit timer, and both master and slave SPI and TWI interfaces. The AVR core is fully static, allowing clock frequencies down to DC for ultra-low-power operation.
Architecture-wise, the ATmega8 couples 32 general-purpose working registers directly to the ALU, so a single instruction can execute an operation between two registers in one clock cycle. Six sleep modes, including Power-down and Power-save, reduce consumption to microamp levels, and a watchdog timer with separate on-chip oscillator adds system reliability. In-system programmability via SPI permits firmware updates after board assembly.
Typical applications include industrial sensor nodes using the 10-bit ADC, battery-powered instrumentation exploiting the 1.8V-class L-family voltage range, motor and lighting control using the three PWM channels, and legacy consumer appliances. It fits designs where 8KB of code space and 8 MHz performance are sufficient at minimal cost.
Design consideration: program the CKOPT and clock-source fuses correctly for the chosen crystal, since an incorrect fuse setting is the most common cause of a non-starting ATmega8 board.
This page synthesizes distributor pricing, drop-in alternatives, pinout data, and practical design notes not found in a single manufacturer datasheet, per web data verified as of 2026-09-19.
Drop-in alternatives for ATMEGA8L-8AI — 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 ATMEGA8L-8AI (same form factor and footprint) — differing in Maximum Clock Frequency, Operating Temperature, Package, ADC Channels, ADC Resolution.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATMEGA8L-8AU
✅ Drop-In✓ In Stock
$1.82 / Unit
View Datasheet →ATMEGA8A-AU
✅ Drop-In✓ In Stock
$1.31 / Unit
View Datasheet →ATMEGA8-16AI
✅ Drop-In✓ In Stock
$2.46 / Unit
View Datasheet →ATMEGA88V-10AU
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$1.58 / Unit
View Datasheet →ATMEGA88PA-AUR
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$0.82 / Unit
View Datasheet →ATMEGA8L-8AI Maximum Ratings & Electrical Characteristics
| Core Processor | AVR |
| Core Size | 8-Bit |
| Max Clock Frequency | 8 MHz |
| Flash Program Memory | 8 KB (4K x 16) |
| SRAM | 1 KB |
| EEPROM | 512 B |
| Operating Voltage Range | 2.7 V to 5.5 V |
| ADC Resolution | 10-bit |
| ADC Channels | 6 or 8 channels |
| Connectivity | I2C (TWI), SPI, UART/USART |
| Timers | Two 8-bit, one 16-bit |
| PWM Channels | 3 |
| Package | 32-TQFP (7x7 mm) |
| Mounting Type | Surface Mount |
| Operating Temperature | -40C to +85C (Industrial) |
| MIPS Throughput | Up to 16 MIPS at 16 MHz (family); 8 MIPS at 8 MHz for this speed grade |
| Instructions | 130 powerful instructions, most single-cycle |
ATMEGA8L-8AI Pin Configuration
| Pin 1 | PD3 (INT1) — Port D bit 3 / External Interrupt 1 |
| Pin 2 | PD4 (T0/XCK) — Port D bit 4 / Timer0 clock or USART external clock |
| Pin 3 | GND — Ground |
| Pin 4 | VCC — Digital supply voltage |
| Pin 5 | GND — Ground |
| Pin 6 | VCC — Digital supply voltage |
| Pin 7 | PB6 (XTAL1/TOSC1) — Port B bit 6 / Crystal oscillator input or Timer oscillator input |
| Pin 8 | PB7 (XTAL2/TOSC2) — Port B bit 7 / Crystal oscillator output or Timer oscillator output |
| Pin 9 | PD5 (T1) — Port D bit 5 / Timer1 external counter input |
| Pin 10 | PD6 (AIN0) — Port D bit 6 / Analog Comparator positive input |
| Pin 11 | PD7 (AIN1) — Port D bit 7 / Analog Comparator negative input |
| Pin 12 | PB0 (ICP1) — Port B bit 0 / Timer1 Input Capture |
| Pin 13 | PB1 (OC1A) — Port B bit 1 / Timer1 PWM output A |
| Pin 14 | PB2 (SS/OC1B) — Port B bit 2 / SPI slave select or Timer1 PWM output B |
| Pin 15 | PB3 (MOSI/OC2) — Port B bit 3 / SPI master output or Timer2 PWM output |
| Pin 16 | PB4 (MISO) — Port B bit 4 / SPI master input |
| Pin 17 | PB5 (SCK) — Port B bit 5 / SPI clock |
| Pin 18 | AVCC — ADC supply voltage |
| Pin 19 | ADC6 — ADC input channel 6 |
| Pin 20 | AREF — ADC analog reference voltage |
| Pin 21 | GND — Ground |
| Pin 22 | ADC7 — ADC input channel 7 |
| 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) — Port C bit 6 / Reset input (active low) |
| Pin 30 | PD0 (RXD) — Port D bit 0 / USART receive |
| Pin 31 | PD1 (TXD) — Port D bit 1 / USART transmit |
| Pin 32 | PD2 (INT0) — Port D bit 2 / External Interrupt 0 |
Typical Applications
ATMEGA8L-8AI is suitable for 6 applications: Industrial Sensor Nodes, Battery-Powered Portable Instruments, Motor and Lighting PWM Control, Legacy Consumer Appliance Control, Educational and Hobby Embedded Platforms, Communication Peripheral Bridges.
Industrial Sensor Nodes
The ATMEGA8L-8AI fits industrial sensor acquisition nodes because its 10-bit ADC with six or eight multiplexed channels digitizes thermistors, pressure bridges, and potentiometers directly without an external converter, while the 2.7V to 5.5V supply range tolerates unregulated 5V industrial rails. Its SPI and TWI interfaces connect to external flash or displays, and the UART links to RS-485 transceivers for long-haul bus networks. The -40C to +85C industrial rating of the -8AI suffix covers factory-floor temperature swings. Typical designs sample sensors every 10-100 ms in an interrupt-driven loop, keeping average current in the low-milliamp range and enabling watchdog-supervised autonomous operation. With 8KB Flash, protocol stacks plus compensation tables fit comfortably, and the 512B EEPROM stores calibration constants that survive power loss.
Recommended
Battery-Powered Portable Instruments
For battery-operated handheld instruments, the low-voltage 'L' variant is the key differentiator: the ATMEGA8L-8AI runs from 2.7V, allowing two-cell alkaline or single lithium-cell operation without a boost converter, and its fully static core supports clock throttling down to DC. Six sleep modes, including Power-down at microamp-level current, let the firmware duty-cycle the CPU between measurements; the asynchronous Timer/Counter2 with a 32.768 kHz watch crystal maintains an RTC during Power-save sleep. The on-chip 10-bit ADC reads the sensor front-end while the internal 2.56V reference provides ratiometric conversion. A design drawing under 5 mA active and sleeping at microamp levels achieves multi-year battery life on AA cells, with the 32-TQFP's small 7x7 mm footprint suiting compact enclosures.
Recommended
Motor and Lighting PWM Control
The three PWM channels of the ATMEGA8L-8AI make it a compact controller for DC motor speed control, LED dimming, and small lighting systems. Two 8-bit timers generate fast PWM for dimming loops, while the 16-bit Timer/Counter1 provides phase-correct PWM at 8-bit to 10-bit resolution for quieter motor drive; at 8 MHz, 8-bit fast PWM reaches roughly 31 kHz, above audible range. The PWM outputs drive MOSFET gate drivers or Darlington stages directly, and the ADC closes the loop by reading current-sense shunts or potentiometer setpoints. The 2.7-5.5V supply range matches both 3.3V logic and 5V gate-driver thresholds, and the brown-out detector plus watchdog timer add protection against rail sags during motor start-up inductance dips.
Recommended
Legacy Consumer Appliance Control
Millions of appliance boards - coffee machines, rice cookers, fan controllers, and thermostats - were built around the ATmega8 family, and the ATMEGA8L-8AI remains a service-part staple for maintaining these production lines. Its combination of 23 GPIO lines, 10-bit ADC for temperature sensing via NTC networks, triac/PWM-friendly timers, and 512B EEPROM for user settings covers the full control loop of a small appliance on one chip. The TWI interface drives LCD or LED display drivers, and the UART supports factory test hooks. For repair and refurbishment workflows, in-system programming over SPI allows firmware patches without desoldering. Because the die is obsoleted, repair shops should dual-source with the pin-compatible ATMEGA8A-AU, which accepts the same socket with a firmware rebuild.
Recommended
Educational and Hobby Embedded Platforms
The ATmega8 family is a classic teaching platform for embedded systems courses and hobbyist projects, and the ATMEGA8L-8AI's 2.7-5.5V tolerance makes breadboard experimentation forgiving of 3.3V or 5V supply choices. Beginners can blink LEDs on 23 GPIO lines within minutes using free avr-gcc toolchains, then progress to the 10-bit ADC for analog lab exercises, UART for PC communication, and SPI/TWI for sensor interfacing - all peripherals introduced in the well-documented manufacturer datasheet. ISP programming requires only six wires from low-cost programmers. With 8 MIPS at 8 MHz, the core is fast enough for mini-projects from line-following robots to audio-tone generators, while the single-cycle RISC model cleanly demonstrates pipeline concepts taught in microprocessor courses.
Recommended
Communication Peripheral Bridges
With native UART, SPI, and TWI/I2C on board, the ATMEGA8L-8AI serves as a protocol bridge in legacy systems - for example converting an I2C sensor bus to UART for a PLC, or gatewaying legacy SPI devices onto RS-232 test equipment. The UART reaches usable baud rates up to 115200 at 8 MHz (with U2X doubling), sufficient for diagnostics and telemetry, while hardware SPI clocks in the MHz range handle fast memory or display transfers. The 8KB Flash accommodates a two-protocol stack plus buffering in the 1KB SRAM. Because the part operates down to 2.7V, it can interface directly with 3V sensor modules through level-tolerant I/O while its 5V rating covers TTL-side connections, reducing discrete level-shifting in mixed-voltage retrofits.
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Recommended Products Summary
Engineering reference data for ATMEGA8L-8AI — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA8L-8AU | ATMEGA8A-AU | ATMEGA8-16AI | ATMEGA88V-10AU | ATMEGA88PA-AUR |
|---|---|---|---|---|---|---|
| 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 |
| Brand | Microchip Technology (Atmel) | Microchip Technology (Atmel) | Microchip Technology (Atmel) | Microchip Technology (Atmel) | Microchip Technology (Atmel) | Microchip Technology (Atmel) |
| Max Clock Frequency | 8 MHz | 8 MHz | 16 MHz | 16 MHz | 10 MHz | 20 MHz |
| Operating Voltage | 2.7 V to 5.5 V | 2.7 V to 5.5 V | 2.7 V to 5.5 V | 4.5 V to 5.5 V (full speed) | 1.8 V to 5.5 V | 1.8 V to 5.5 V |
| Flash / SRAM / EEPROM | 8 KB / 1 KB / 512 B | 8 KB / 1 KB / 512 B | 8 KB / 1 KB / 512 B | 8 KB / 1 KB / 512 B | 8 KB / 1 KB / 512 B | 8 KB / 1 KB / 512 B |
| Firmware Compatibility | ATmega8 register set | Identical (same die) | Recompile, revised die errata | Identical (same die) | ATmega88 register map - porting required | ATmega88 register map - porting required |
Key Differentiators
- Low-voltage operation down to 2.7V at full 8 MHz speed (vs ATMEGA8-16AI)
- Maximum long-term availability of the family (vs ATMEGA8L-8AU)
- Simplest migration path to an active part (vs ATMEGA88PA-AUR)
Design Notes
Clock fuses are the number-one failure mode on ATmega8 boards. The CKSEL3..0 fuses must match the chosen clock source (e.g., 0b1111 for a low-power crystal above 8 MHz), and the CKOPT fuse must be programmed for full-swing operation in noisy industrial environments. If RSTDISBL is accidentally set, RESET becomes a GPIO and the part can no longer be ISP-programmed. Always reprogram fuses before first production flash and keep a documented known-good fuse configuration, since an ATmega8 with wrong fuses looks electrically dead on the bench.
Decouple both VCC pins (pins 4 and 6) with 100 nF ceramic capacitors placed within 5 mm of each pin, and provide AVCC (pin 18) with its own RC filter - a ferrite bead plus 100 nF plus 10 uF - even if AVCC is tied to VCC. The 10-bit ADC accuracy degrades noticeably when AVCC carries digital switching noise from Port B and Port D toggling. For battery designs, enable the internal 2.56V bandgap reference for ratiometric measurements and disable it via the ADC multiplexer selection in sleep to cut reference current.
The 32-TQFP 0.8 mm pitch footprint is hand-solderable but requires no-clean flux management to avoid bridging pins 28-29 (SCL/RESET), where a short disables TWI communication. Route the AREF trace away from XTAL1/XTAL2 clock lines and guard it with ground to prevent ADC reference coupling. Because the part is obsolete and rework stock is scarce, consider laying out the footprint so both the ATmega8 and pin-compatible ATmega88PA fit, enabling a no-layout-change second source during last-time-buy transitions.
Reset (pin 29, PC6) is the most noise-sensitive line on the board in industrial settings. Fit a 10 kOhm pull-up and place a 100 nF capacitor from RESET to ground close to the pin to filter transients that could spuriously reset the MCU during motor switching or ESD events. If an external programmer header is present, series resistors of 470 Ohm on MOSI/MISO/SCK protect both the MCU and the programmer from bus contention. Keep the UART RXD/TXD traces short or add ESD protection for cable-connected ports.
Compliance Information
Part is obsolete; Microchip product page no longer publishes an active compliance certificate for this suffix. The later -8AU Green package is generally RoHS/halogen-free, but the -8AI compliance status must be confirmed with the supplier by date code.
