ATMEGA8-16MJ - 8-bit AVR MCU 16MHz 8KB Flash 32-VQFN | Microchip
MPN: ATMEGA8-16MJ ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.1 | $3.10 |
| 10 | $2.79 | $27.90 |
| 100 | $2.48 | $248.00 |
| 500 | $2.23 | $1,115.00 |
| 1,000 | $1.98 | $1,980.00 |
ATMEGA8-16MJ Overview
An 8-bit microcontroller (MCU) is a single-chip computer that integrates a processor core, program memory, data memory, and peripherals on one die. Within the power/performance hierarchy, it sits as: AVR ATmega core -> 8-bit microcontroller -> embedded processor -> system-on-board controller. MCUs of this class run firmware directly from Flash and are the backbone of cost-sensitive embedded control systems.
Key features include the Advanced RISC architecture with 130 powerful instructions, most executed in a single clock cycle; 32 general-purpose 8-bit working registers; three flexible Timer/Counters with compare modes; a programmable serial USART; and an internal RC oscillator option that removes the need for an external crystal in many designs.
Technically, the AVR Harvard architecture separates program and data buses, enabling Read-While-Write Flash programming and single-cycle instruction execution. The 6- or 8-channel 10-bit ADC, two-wire (I2C-compatible) interface, and SPI port cover most sensing and communication needs in a single chip. In-System Programming via SPI allows firmware updates without removing the device from the board.
Typical applications include industrial automation control nodes, consumer appliance controllers, and embedded sensor systems where a 16 MHz, 8 KB Flash budget is sufficient and the compact 5x5 mm QFN footprint saves board space.
Design consideration: the -MJ suffix indicates the industrial temperature MLF package; verify voltage range and brown-out fuse settings against your supply rail, and use the exposed pad as ground for best thermal and EMI performance.
This page synthesizes distributor availability, drop-in alternative analysis, and pinout detail not consolidated in the manufacturer datasheet. Pricing shown as of 2026-09-18.
Drop-in alternatives for ATMEGA8-16MJ — 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 ATMEGA8-16MJ (same form factor and footprint) — differing in Communication Interfaces, EEPROM, Flash Program Memory, Package, SRAM.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATMEGA8-16MU
✅ Drop-In✓ In Stock
$1.62 / Unit
View Datasheet →ATMEGA8L-8MJ
✅ Drop-In ⚠️ 参数待验证✓ In Stock
Contact for price
View Datasheet →ATMEGA48-20MJ
✅ Drop-In ⚠️ 参数待验证✓ In Stock
Contact for price
View Datasheet →ATMEGA88-20MJ
✅ Drop-In✓ In Stock
$1.24 / Unit
View Datasheet →ATMEGA168-20MJ
✅ Drop-In ⚠️ 参数待验证📋 Reference alternative (not in catalog)
ATMEGA8-16MJ Maximum Ratings & Electrical Characteristics
| Core Architecture | 8-bit AVR RISC |
| Clock Speed | 16 MHz |
| Flash Program Memory | 8 KB (4K x 16) |
| SRAM | 1 KB (1K x 8) |
| EEPROM | 512 bytes |
| I/O Lines | 23 |
| Instruction Count | 130 instructions |
| Oscillator Type | Internal (with external option) |
| ADC | 10-bit, 6 or 8 channel |
| Timers | 3 Timer/Counters with compare modes |
| Communication Interfaces | USART, SPI, 2-wire (I2C-compatible) |
| Package | 32-VFQFN Exposed Pad (MLF-32, 5x5 mm) |
| Mounting Type | Surface Mount |
| Packaging | Tray |
| Throughput | 16 MIPS at 16 MHz |
| Program Features | In-System Programmable Flash with Read-While-Write |
| Working Registers | 32 x 8-bit general purpose |
ATMEGA8-16MJ Pin Configuration
| Pin 1 | PC6 (RESET) — Port C bit 6 / Reset input (active low) |
| Pin 2 | PD0 (RXD) — Port D bit 0 / USART receive |
| Pin 3 | PD1 (TXD) — Port D bit 1 / USART transmit |
| 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 counter input or USART external clock |
| Pin 7 | VCC — Digital supply voltage |
| Pin 8 | GND — Ground |
| Pin 9 | GND — Ground |
| Pin 10 | GND — Ground |
| Pin 11 | PB6 (XTAL1/TOSC1) — Port B bit 6 / Oscillator or timer oscillator input |
| Pin 12 | PB7 (XTAL2/TOSC2) — Port B bit 7 / Oscillator or timer oscillator output |
| Pin 13 | PD5 (T1/OC1A) — Port D bit 5 / Timer1 counter input or Timer1 compare A output |
| Pin 14 | PD6 (ICP1/AIN0) — Port D bit 6 / Timer1 input capture or analog comparator positive input |
| Pin 15 | PD7 (OC2/AIN1) — Port D bit 7 / Timer2 compare output or analog comparator negative input |
| Pin 16 | PB0 (ICP1) — Port B bit 0 |
| Pin 17 | PB1 (OC1A) — Port B bit 1 / Timer1 compare A output |
| Pin 18 | PB2 (SS/OC1B) — Port B bit 2 / SPI slave select or Timer1 compare B output |
| Pin 19 | PB3 (MOSI/OC2) — Port B bit 3 / SPI master output or Timer2 compare output |
| Pin 20 | PB4 (MISO) — Port B bit 4 / SPI master input |
| Pin 21 | PB5 (SCK) — Port B bit 5 / SPI serial clock |
| Pin 22 | AVCC — Analog supply voltage for ADC |
| Pin 23 | AREF — ADC analog reference voltage |
| Pin 24 | GND — Ground |
| Pin 25 | PC0 (ADC0) — Port C bit 0 / ADC channel 0 |
| Pin 26 | PC1 (ADC1) — Port C bit 1 / ADC channel 1 |
| Pin 27 | PC2 (ADC2) — Port C bit 2 / ADC channel 2 |
| Pin 28 | PC3 (ADC3) — Port C bit 3 / ADC channel 3 |
| Pin 29 | PC4 (ADC4/SDA) — Port C bit 4 / ADC channel 4 or 2-wire data |
| Pin 30 | PC5 (ADC5/SCL) — Port C bit 5 / ADC channel 5 or 2-wire clock |
| Pin 31 | GND — Ground |
| Pin 32 | VCC — Digital supply voltage |
Typical Applications
ATMEGA8-16MJ is suitable for 6 applications: Industrial Automation Control Nodes, Embedded Sensor Systems, Consumer Appliance Controllers, Hobbyist and Educational Embedded Platforms, Motor Control and PWM Drive, Serial Communication Converters and Protocol Bridges.
Industrial Automation Control Nodes
The ATMEGA8-16MJ fits industrial control and monitoring nodes where deterministic single-cycle 16 MHz RISC execution and 23 GPIO lines drive relays, optocouplers, and indicator logic without an external controller. Its three Timer/Counters with compare modes generate PWM for motor or heater control at fixed frequencies, while the USART links the node to SCADA-style serial networks at standard baud rates. The internal oscillator option simplifies boards that tolerate a few percent clock tolerance, cutting BOM cost by removing the crystal and load capacitors. With 8 KB Flash and Read-While-Write programming, firmware field updates occur over the same SPI header used for production programming. In the 5x5 mm MLF-32 footprint, designers fit control logic into existing module housings without layout expansion.
Recommended
Embedded Sensor Systems
Sensor front-ends benefit from the ATMEGA8-16MJ's integrated 10-bit ADC with 6 or 8 input channels, converting thermistors, potentiometers, and bridge-style outputs without an external converter. The 2.7 V to 5.5 V supply range matches common sensor rails, and AVCC/AREF pins allow quiet analog power domains separate from the digital core. Acquired values stream out over SPI or the 2-wire interface to a host, or over USART to a logger. At 16 MHz the core executes averaging and thresholding filters with ample headroom inside 1 KB SRAM for multi-channel buffers. Because the ADC, processor, and communication occupy one 5x5 mm MLF-32 package, sensor PCBs shrink significantly versus discrete designs, and tray packaging suits medium-volume production builds.
Recommended
Consumer Appliance Controllers
Appliance control boards - coffee machines, fans, small heaters - use the ATMEGA8-16MJ to sequence loads, read buttons, and drive 7-segment or LED indicators. The 130-instruction AVR core handles debounce timing, PWM phase control for AC dimming, and safety interlocks inside single-clock-cycle execution, keeping worst-case response predictable. Internal oscillator operation avoids crystal cost in appliances where exact timing is not critical, while the external XTAL option remains available for UART-based service diagnostics. The MLF-32 package's exposed pad bonds to ground pour, improving EMI margin to meet household emissions limits at minimal layout effort. With 512 bytes of EEPROM, calibration values and user settings survive power cycles without external memory, reducing BOM count in high-volume consumer products.
Recommended
Hobbyist and Educational Embedded Platforms
The ATmega8 family is a fixture in education and hobby electronics, supported by the MiniCore Arduino hardware package (MCUdude/MiniCore on GitHub), which enables Arduino IDE sketches on ATmega8, ATmega48/88/168/328 devices. The ATMEGA8-16MJ's 16 MIPS performance runs introductory robotics, LED matrix, and serial-communication exercises with real headroom, while the 130-instruction AVR assembly set is small enough for a semester syllabus. ISP programming via the SPI port requires only a 6-pin header, making breadboard and QFN-adapter prototyping straightforward. The MLF-32 package teaches QFN soldering skills relevant to professional practice. Ample community documentation, datasheets, and code examples lower the learning curve compared with less-documented 8-bit families.
Recommended
Motor Control and PWM Drive
Small DC motor and servo control uses the ATMEGA8-16MJ's Timer/Counter compare outputs to produce hardware PWM independent of software jitter. The 16 MHz clock yields PWM resolution fine enough for smooth speed control on fans, pumps, and hobby servos, while the input-capture function on Timer1 measures tachometer pulses for closed-loop speed regulation. GPIO drive the pre-driver stage or gate resistors of discrete H-bridges; the 23 I/O lines accommodate limit switches and encoder quadrature inputs simultaneously. The MLF-32's exposed thermal pad provides a low-impedance ground that reduces switching-noise coupling into the ADC when current sensing is performed on-board. Firmware structures map cleanly onto the three-timer resource set without peripheral reuse conflicts.
Recommended
Serial Communication Converters and Protocol Bridges
The ATMEGA8-16MJ's programmable USART, SPI, and 2-wire interfaces make it a compact protocol bridge: converting RS-232 device streams to I2C peripherals, buffering SPI sensor data for UART telemetry, or implementing custom MODBUS-style polling loops. At 16 MHz the core sustains standard UART rates with interrupt-driven buffering inside 1 KB SRAM, and the 130-instruction RISC set keeps ISR latency short for unattended byte handling. Read-While-Write Flash lets the device log small datasets to program memory between transmissions where EEPROM capacity (512 bytes) is insufficient. The 5x5 mm MLF-32 footprint and industrial build suit DIN-rail adapters and cable-mounted converter pods, while tray packaging supports contract-manufactured production runs.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA8-16MJ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA8-16MU | ATMEGA8L-8MJ | ATMEGA48-20MJ | ATMEGA88-20MJ |
|---|---|---|---|---|---|
| Package | 32-VFQFN Exposed Pad (MLF-32, 5x5 mm) | 32-VFQFN Exposed Pad (MLF-32) - same | 32-VFQFN Exposed Pad (MLF-32) - same | 32-VFQFN (MLF-32) - same footprint | 32-VFQFN (MLF-32) - same footprint |
| Brand | Microchip Technology (Atmel) | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Max Clock Speed | 16 MHz | 16 MHz | 8 MHz | 20 MHz | 20 MHz |
| Flash Memory | 8 KB (4K x 16) | 8 KB | 8 KB | 4 KB | 8 KB |
| SRAM | 1 KB | 1 KB | 1 KB | 512 B | 1 KB |
| EEPROM | 512 bytes | 512 bytes | 512 bytes | 256 bytes | 512 bytes |
| I/O Lines | 23 | 23 | 23 | 23 | 23 |
| Firmware Compatibility with ATmega8 Code | Native | Native - no changes | Native - clock limits apply | Port required (register/fuse map differs) | Port per AVR094 app note |
Key Differentiators
- Zero-firmware-change drop-in availability (vs ATMEGA8-16MU)
- Full-speed industrial-grade AVR performance (vs ATMEGA8L-8MJ)
- Twice the memory of the cost-optimized sibling (vs ATMEGA48-20MJ)
- Honest trade-off: lower max clock than newer family members (vs ATMEGA88-20MJ)
Design Notes
The MLF-32 package's exposed die pad is the primary ground connection and must be soldered to a ground pour - a floating thermal pad causes unreliable ground return and poor EMI performance. Use a 3x3 via array (5-7 vias) under the pad to the ground plane for both electrical and thermal benefit. Per the ATmega8 datasheet land-pattern guidance, use non-solder-mask-defined (NSMD) pads with solder paste aperture reductions of roughly 50-70% to prevent QFN bridging between the 0.5 mm pitch pins.
Decouple each VCC pin (7 and 32) and AVCC (22) with 100 nF ceramic capacitors placed within 2-3 mm of the respective pins, plus one bulk 10 uF per board section. AVCC must be connected even when the ADC is unused - per the datasheet it should be within 0.3 V of VCC; connecting AVCC to VCC through a small LC filter improves ADC noise performance in mixed-signal designs. Tie AREF to a decoupled reference with 100 nF; never leave AREF floating when the ADC is enabled.
Fuse settings are a frequent failure source: an ATmega8 programmed for external crystal but shipped without one will appear completely dead because there is no internal clock fallback (unlike ATmega88). Always verify lock/fuse bits with a programmer before assuming hardware failure. Also note the -16 speed grade requires a 4.5-5.5 V supply for guaranteed 16 MHz operation; running at 3.3 V violates the datasheet frequency-versus-voltage envelope and causes marginal, temperature-dependent failures.
When using XTAL1/XTAL2 (PB6/PB7) with an external crystal, keep the crystal and its load capacitors within 5 mm of the pins and guard them with ground pour on the top layer. Route reset (PC6) away from switching traces and add a 10 k pull-up; a series 100 ohm resistor in the reset line suppresses ringing during fast transients. For SPI/ISP headers, keep traces under 10 cm to preserve programming reliability.
Compliance Information
RoHS/REACH/lead-free status was not captured in the retrieved web data for this exact MPN. Current-production ATmega8 MLF parts from Microchip are typically RoHS-compliant, but confirm on the Microchip product page or DigiKey environmental listing before compliance-critical release.
