ATMEGA168A-AUR - 8-bit AVR MCU 16KB 20MHz | Microchip
MPN: ATMEGA168A-AUR β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.32 | $2.32 |
| 10 | $2.09 | $20.90 |
| 100 | $1.86 | $186.00 |
| 500 | $1.63 | $815.00 |
| 1,000 | $1.45 | $1,450.00 |
ATMEGA168A-AUR Overview
An 8-bit microcontroller is an integrated circuit whose CPU processes data in 8-bit words, combining a processor core, program memory (FLASH), data memory (SRAM and EEPROM), and peripherals such as timers and serial interfaces on a single chip. MCUs sit at the heart of the embedded-systems hierarchy - below application processors but above simple logic ICs - serving as the primary control element in industrial, consumer, and automotive electronics.
The ATMEGA168A executes 133 powerful instructions, most in a single clock cycle, achieving up to 20 MIPS throughput at 20 MHz. It provides 512 B of EEPROM with read-while-write FLASH capability, 1 KB of internal SRAM, and 23 general purpose I/O lines. Peripheral resources include a serial programmable USART, a byte-oriented two-wire serial interface (I2C/TWI), an SPI serial port, three flexible timer/counters with compare modes, and a 10-bit ADC.
The AVR advanced RISC architecture uses 32 general purpose working registers directly connected to the ALU, allowing a single-cycle execution model that outperforms conventional CISC microcontrollers at equivalent clock rates. In-system programmability (ISP) allows firmware updates on the assembled PCB via SPI, reducing production cost and field-upgrade effort. Internal brown-out detection, power-on reset, and an enhanced power-save mode support robust, low-power designs.
Typical applications include industrial control systems, HVAC and building automation, sensor nodes and battery-operated instruments, consumer appliances, and Arduino-compatible embedded boards where the pin-compatible ATmega family simplifies design migration.
When designing with this device, keep the supply within 2.7V to 5.5V and respect the 20 MHz ceiling; below 8 MHz the part can operate across its full voltage range, so choose the clock accordingly.
This page synthesizes verified distributor pricing, drop-in alternatives across the ATmega family, complete TQFP-32 pinout data, and practical design notes not consolidated in the manufacturer datasheet.
Drop-in alternatives for ATMEGA168A-AUR β 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 ATMEGA168A-AUR (same form factor and footprint) β differing in ADC Resolution, Core Processor, Program Memory Size, RoHS Status, Supply Voltage Range.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATMEGA168PA-AUR
β Drop-In β οΈ εζ°εΎ ιͺθ―β In Stock
$1.85 / Unit
View Datasheet βATMEGA328P-AUR
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA328-AUR
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA88A-AUR
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA48A-AUR
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA168-20AUR
β Drop-Inβ In Stock
$2.76 / Unit
View Datasheet βATMEGA168A-AUR Maximum Ratings & Electrical Characteristics
| Core Processor | AVR |
| Core Size | 8-Bit |
| Speed | 20 MHz |
| Program Memory Size | 16 KB (8K x 16) FLASH |
| EEPROM Size | 512 B |
| RAM Size | 1 KB |
| Supply Voltage Range | 2.7 V to 5.5 V |
| Number of I/O | 23 |
| Connectivity | I2C, SPI, UART/USART |
| Peripherals | Brown-out Detect/Reset, POR, PWM, WDT |
| Timers | Three flexible timer/counters with compare modes |
| Data Converters | 10-bit ADC |
| Instructions | 133 powerful instructions, most single-cycle |
| Package | 32-TQFP (7x7 mm) |
| Mounting Type | Surface Mount |
| Programming | In-System Programmable (ISP) FLASH with read-while-write |
| Lifecycle Stage | Active |
ATMEGA168A-AUR Pin Configuration
| Pin 1 | PD3 β Port D, bit 3 (GPIO / interrupt source) |
| Pin 2 | PD4 β Port D, bit 4 (GPIO) |
| Pin 3 | GND β Ground |
| Pin 4 | VCC β Digital supply voltage (2.7V to 5.5V) |
| Pin 5 | GND β Ground |
| Pin 6 | VCC β Digital supply voltage |
| Pin 7 | PB6 β Port B, bit 6 (XTAL1 / TOSC1) |
| Pin 8 | PB7 β Port B, bit 7 (XTAL2 / TOSC2) |
| Pin 9 | PD5 β Port D, bit 5 (GPIO) |
| Pin 10 | PD6 β Port D, bit 6 (GPIO) |
| Pin 11 | PD7 β Port D, bit 7 (GPIO) |
| Pin 12 | PB0 β Port B, bit 0 (GPIO) |
| Pin 13 | PB1 β Port B, bit 1 (GPIO) |
| Pin 14 | PB2 β Port B, bit 2 (GPIO) |
| Pin 15 | PB3 β Port B, bit 3 (MOSI / SPI master output) |
| Pin 16 | PB4 β Port B, bit 4 (MISO / SPI master input) |
| Pin 17 | PB5 β Port B, bit 5 (SCK / SPI clock) |
| Pin 18 | AVCC β ADC supply voltage |
| Pin 19 | ADC6 β ADC input channel 6 |
| Pin 20 | AREF β Analog reference voltage for ADC |
| Pin 21 | GND β Ground |
| Pin 22 | ADC7 β ADC input channel 7 |
| Pin 23 | PC0 β Port C, bit 0 (ADC0) |
| Pin 24 | PC1 β Port C, bit 1 (ADC1) |
| Pin 25 | PC2 β Port C, bit 2 (ADC2) |
| Pin 26 | PC3 β Port C, bit 3 (ADC3) |
| Pin 27 | PC4 β Port C, bit 4 (ADC4 / SDA, TWI data) |
| Pin 28 | PC5 β Port C, bit 5 (ADC5 / SCL, TWI clock) |
| Pin 29 | PC6 β RESET (active-low reset input) |
| Pin 30 | PD0 β Port D, bit 0 (RXD, USART receive) |
| Pin 31 | PD1 β Port D, bit 1 (TXD, USART transmit) |
| Pin 32 | PD2 β Port D, bit 2 (GPIO / interrupt source) |
Typical Applications
ATMEGA168A-AUR is suitable for 6 applications: Industrial Control and Automation, HVAC and Building Automation, Sensor Nodes and Battery Instruments, Consumer Appliances and White Goods, Arduino-Compatible and Educational Boards, Motor Control and PWM Actuation.
Industrial Control and Automation
The ATMEGA168A-AUR fits industrial control nodes where deterministic 8-bit control loops, USART communication, and robust power supervision matter more than raw processing horsepower. Its 133 single-cycle AVR instructions deliver up to 20 MIPS at 20 MHz - sufficient for PID control of motor drives, relay sequencing, and PLC-style I/O scanning. The brown-out detector and power-on reset guarantee clean restarts on noisy factory power rails, while the internal watchdog timer recovers from firmware lockups without external components. The byte-oriented TWI interface chains multiple sensor modules on one two-wire bus, and the SPI port drives displays or ADC front-ends. Operating across 2.7V to 5.5V, it tolerates unregulated 5V industrial supplies directly.
Recommended
HVAC and Building Automation
In HVAC controllers, thermostat panels, and room-sensor nodes, the ATMEGA168A-AUR combines a 10-bit ADC for temperature, humidity, and pressure front-ends with the enhanced power-save mode for low average consumption. The three timer/counters with compare modes generate PWM for damper servo and fan-speed control without CPU overhead. The USART links the node to RS-485 gateways, while TWI (I2C) reads digital temperature sensors directly. The 2.7V to 5.5V supply range supports both battery-backup and 5V mains-derived rails. With 16 KB FLASH and read-while-write capability, calibration tables stored in the 512 B EEPROM can be updated in the field via ISP without interrupting program execution.
Recommended
Sensor Nodes and Battery Instruments
Portable and battery-powered instruments benefit from the ATMEGA168A-AUR power-save mode, which idles the core while timers keep running for periodic wake-up and ADC sampling. The 10-bit ADC plus the two extra channels ADC6 and ADC7 available in the 32-TQFP package allow multi-channel sensor acquisition without an external multiplexer. The internal 1 KB SRAM handles buffering and filtering of sample streams, and the USART streams results to a host or logger. Because the core executes most instructions in a single clock cycle, the CPU can sleep between conversions even at modest clock rates, extending battery life. The 2.7V floor allows operation from two alkaline cells with a simple LDO.
Recommended
Consumer Appliances and White Goods
Appliance control boards - coffee machines, fans, small pumps, and lighting products - use the ATMEGA168A-AUR for its low BOM cost, single-chip integration of POR, brown-out detect, watchdog, and PWM, and its wide 2.7V to 5.5V operating range suited to cost-optimized power supplies. The 16 KB FLASH accommodates UI state machines, key-scanning, and display drivers, while the three timers generate both display multiplexing and triac/PWM actuation signals. In-system programmability allows one firmware image to be flashed at end-of-line test on the assembled board, simplifying manufacturing. The active lifecycle status and multi-distributor availability protect long product runs against component obsolescence.
Recommended
Arduino-Compatible and Educational Boards
The ATmega168 is a founding member of the pin-compatible ATmega 8/88/168/328 family that underpins Arduino-compatible boards and the MiniCore hardware package, giving the ATMEGA168A-AUR immediate access to a mature open-source toolchain, bootloaders, and library ecosystem. The 16 KB FLASH holds the Arduino bootloader plus user sketches, the USART implements USB-serial sketch upload, and SPI/TWI drive shields and sensor modules. Designers migrating between ATmega88, 168, and 328 reuse the same PCB footprint and programmer hardware, since the 32-TQFP pinout is identical across the family. This makes the part ideal for STEM kits, hobby boards, and rapid prototypes before a production spin.
Recommended
Motor Control and PWM Actuation
Small motor drives, servo actuators, and LED dimming circuits exploit the ATMEGA168A-AUR three flexible timer/counters with compare modes to generate complementary PWM outputs with hardware dead-time behavior, offloading waveform generation from software. The AVR executes control-loop code in single clock cycles, so a 20 MHz device closes current loops at multi-kilohertz rates with margin. The 10-bit ADC reads shunt or hall feedback, the USART connects to higher-level controllers, and the watchdog enforces failsafe shutdown if firmware stalls. With 23 I/O lines, a single 32-TQFP device handles encoder inputs, limit switches, and fault inputs alongside the PWM outputs, reducing board area and component count.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA168A-AUR β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA168PA-AUR | ATMEGA328P-AUR | ATMEGA88A-AUR | ATMEGA168-20AUR |
|---|---|---|---|---|---|
| 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 |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 16 KB | 16 KB | 32 KB | 8 KB | 16 KB |
| SRAM | 1 KB | 1 KB | 2 KB | 1 KB | 1 KB |
| EEPROM | 512 B | 512 B | 1 KB | 512 B | 512 B |
| Max Clock Speed | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| Supply Voltage | 2.7 V to 5.5 V | 1.8 V to 5.5 V (picoPower) | 1.8 V to 5.5 V (picoPower) | 2.7 V to 5.5 V | 2.7 V to 5.5 V |
| Power Technology | Standard ATmega168A core | picoPower (lower sleep current) | picoPower | Standard A-grade core | Predecessor (non-A) core |
| Pin Compatibility | ATmega 8/88/168/328 TQFP-32 family pinout | Pin-to-pin compatible | Pin-to-pin compatible | Pin-to-pin compatible | Pin-to-pin compatible |
Key Differentiators
- Best price/performance within the pin-compatible family at 16 KB (vs ATMEGA328P-AUR)
- Balanced 16 KB / 1 KB / 512 B memory configuration (vs ATMEGA88A-AUR)
- Lower unit cost than picoPower variants when sleep current is not critical (vs ATMEGA168PA-AUR)
- Updated A-process die versus the original ATmega168 (vs ATMEGA168-20AUR)
Design Notes
Decouple both VCC pins (pins 4 and 6) and the AVCC pin (pin 18) independently: place 100 nF ceramic capacitors within 5 mm of each supply pin plus a 10 uF bulk capacitor near the device. Tie AVCC to VCC through a low-pass filter (e.g., 10 ohm series resistor plus 100 nF) when ADC accuracy matters; AVCC must never exceed VCC by more than 0.3 V. The 2.7V minimum supply means designs running from a 3.3V rail are fully supported, but verify the speed-versus-voltage derating curve in the manufacturer datasheet before running 20 MHz near the voltage floor.
The 32-TQFP (7x7 mm) exposes no thermal pad, so thermal management is straightforward, but routing discipline matters for the crystal and analog section. Keep the XTAL1/XTAL2 traces (pins 7 and 8) short (under 10 mm) and surround them with a guard ground to prevent stray coupling that can stop the oscillator. Route ADC sensor signals away from the SPI clock (PB5) and USART TX lines, and reserve pins ADC6/ADC7 (pins 19 and 22) for the most noise-sensitive analog channels since they connect directly to the ADC mux with minimal internal routing.
PC6 (pin 29) is the dedicated RESET pin - do not configure it as a weak I/O drive without understanding that clearing the RESET-disable fuse locks out further ISP programming. When migrating firmware from ATMEGA88A or ATMEGA328P, verify EEPROM addressing and flash-size-dependent constants, and confirm fuse settings (clock source, brown-out threshold) are re-checked for the target variant. Supplying the part below 2.7 V with a 20 MHz clock is outside the verified specification for this ordering code - either lower the clock or select a picoPower variant such as ATMEGA168PA-AUR with a wider voltage range.
For ISP programming via the SPI pins (PB3/MOSI, PB4/MISO, PB5/SCK, PC6/RESET), place a series 100 ohm resistor on SCK close to the programming header to damp ringing on long cables. On the TWI bus (PC4/SDA, PC5/SCL), use 4.7 kohm pull-ups at 5V operation (10 kohm at 3.3V) and keep bus capacitance under 400 pF per the two-wire interface specification. These practice notes follow standard AVR hardware design guidance from Microchip application documentation rather than a specific datasheet figure.
Compliance Information
The -AUR ordering suffix indicates RoHS-compliant, lead-free, tape-and-reel packaging per Microchip ordering-code convention. Formal REACH and conflict-minerals declarations should be obtained from the Microchip product page compliance portal.
