ATMEGA168-20AUR - 8-bit AVR MCU 20MHz 16KB Flash | Microchip
MPN: ATMEGA168-20AUR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.89 | $3.89 |
| 10 | $3.55 | $35.50 |
| 100 | $3.25 | $325.00 |
| 500 | $3 | $1,500.00 |
| 1,000 | $2.76 | $2,760.00 |
ATMEGA168-20AUR Overview
An 8-bit AVR microcontroller is a single-chip computer that integrates a RISC processor core, program flash memory, data SRAM, non-volatile EEPROM, peripherals, and general-purpose I/O in one package. Within the power-management and embedded hierarchy, the ATmega family sits among general-purpose MCUs that replace multi-chip processor plus memory designs, reducing board area, BOM cost, and power consumption for embedded control systems.
Key differentiating features include the advanced RISC architecture with 133 powerful instructions, most executing in a single clock cycle; 23 programmable I/O lines; three flexible timer/counters with compare modes; an 8-channel 10-bit ADC; and debugWIRE on-chip debugging. The device operates from a single 2.7V to 5.5V supply and supports read-while-write self-programming for field firmware updates via ISP.
Technically, the AVR core uses a Harvard architecture with separate program and data buses and 32 general-purpose working registers directly connected to the ALU, allowing two independent registers to be accessed in one instruction. This eliminates the accumulator bottleneck of classic 8051-style cores and underpins the 1 MIPS/MHz efficiency rating. In-system programmable flash with boot-section support enables self-hosted firmware upgrades over UART, CAN, or any serial interface.
Typical applications include Arduino-compatible boards and hobby/embedded prototyping, industrial sensor nodes and motor control, and consumer appliance control panels. The 20 MHz clock and rich peripheral set fit both cost-sensitive and performance-sensitive designs.
Design consideration: at 5V the device is rated to 20 MHz, but below 2.7V operation the safe maximum frequency derates - consult the frequency-versus-voltage curve in the manufacturer datasheet before overclocking low-voltage designs.
This page synthesizes verified distributor pricing, drop-in alternatives, pinout data, and practical design notes not consolidated in the manufacturer datasheet.
Drop-in alternatives for ATMEGA168-20AUR — 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 ATMEGA168-20AUR (same form factor and footprint) — differing in Timers, Package, Throughput, Supply Voltage Range, ADC Resolution.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATMEGA168A-AUR
✅ Drop-In✓ In Stock
$1.45 / Unit
View Datasheet →ATMEGA168-20AU
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$1.82 / Unit
View Datasheet →ATMEGA168-20AI
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$1.85 / Unit
View Datasheet →ATMEGA168PA-AUR
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$1.85 / Unit
View Datasheet →ATMEGA328P-AUR
✅ Drop-In📋 Reference alternative (not in catalog)
ATMEGA164PA-AUR
✅ Drop-In✓ In Stock
$2.05 / Unit
View Datasheet →ATMEGA165PA-AU
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$2.05 / Unit
View Datasheet →ATMEGA168-20AUR Maximum Ratings & Electrical Characteristics
| Core Processor | AVR |
| Core Size | 8-Bit |
| Speed | 20 MHz |
| Flash Memory | 16 KB (8K x 16) |
| EEPROM | 512 B |
| RAM Size | 1 KB |
| Number of I/O | 23 |
| ADC Resolution | 10-bit, 8 channels |
| Supply Voltage Range | 2.7 V to 5.5 V |
| Timers/Counters | 3 |
| Communication Interfaces | USART, SPI, I2C (TWI) |
| Package | 32-TQFP (7x7 mm) |
| Mounting Type | Surface Mount |
| On-Chip Debug | debugWIRE |
| In-System Programming | Yes (ISP, read-while-write) |
| Programmable Instructions | 133 (most single-cycle) |
| RoHS Status | Compliant |
ATMEGA168-20AUR Pin Configuration
| Pin 1 | PD3 — Port D, bit 3 (GPIO / PWM OC2B) |
| Pin 2 | PD4 — Port D, bit 4 (GPIO / XCK/T0) |
| Pin 3 | GND — Ground |
| Pin 4 | VCC — Digital supply voltage |
| Pin 5 | GND — Ground |
| Pin 6 | VCC — Digital supply voltage |
| Pin 7 | PB6 — Port B, bit 6 (XTAL1/TOSC1 - crystal oscillator input) |
| Pin 8 | PB7 — Port B, bit 7 (XTAL2/TOSC2 - crystal oscillator output) |
| Pin 9 | PD5 — Port D, bit 5 (GPIO / PWM OC0B/T1) |
| Pin 10 | PD6 — Port D, bit 6 (GPIO / PWM OC0A/AIN0) |
| Pin 11 | PD7 — Port D, bit 7 (GPIO / AIN1 analog comparator input) |
| Pin 12 | PB0 — Port B, bit 0 (GPIO / ICP1/CLKO) |
| Pin 13 | PB1 — Port B, bit 1 (GPIO / PWM OC1A) |
| Pin 14 | PB2 — Port B, bit 2 (GPIO / SS/OC1B) |
| Pin 15 | PB3 — Port B, bit 3 (SPI MOSI / PWM OC2A) |
| Pin 16 | PB4 — Port B, bit 4 (SPI MISO) |
| Pin 17 | PB5 — Port B, bit 5 (SPI SCK) |
| Pin 18 | AVCC — ADC supply voltage (must be connected to VCC via low-pass filter) |
| Pin 19 | ADC6 — ADC input channel 6 (TQFP/QFN packages only) |
| Pin 20 | AREF — ADC analog reference input |
| Pin 21 | GND — Ground |
| Pin 22 | ADC7 — ADC input channel 7 (TQFP/QFN packages only) |
| Pin 23 | PC0 — Port C, bit 0 (ADC0 / I2C not on this pin, GPIO) |
| Pin 24 | PC1 — Port C, bit 1 (ADC1, GPIO) |
| Pin 25 | PC2 — Port C, bit 2 (ADC2, GPIO) |
| Pin 26 | PC3 — Port C, bit 3 (ADC3, GPIO) |
| Pin 27 | PC4 — Port C, bit 4 (ADC4 / I2C SDA) |
| Pin 28 | PC5 — Port C, bit 5 (ADC5 / I2C SCL) |
| Pin 29 | PC6 — Port C, bit 6 (RESET - active low reset / GPIO when RSTDISBL fused) |
| Pin 30 | PD0 — Port D, bit 0 (USART RXD) |
| Pin 31 | PD1 — Port D, bit 1 (USART TXD) |
| Pin 32 | PD2 — Port D, bit 2 (GPIO / INT0 external interrupt) |
Typical Applications
ATMEGA168-20AUR is suitable for 6 applications: Arduino-Compatible Hobby and Prototyping Boards, Industrial Sensor Nodes, Consumer Appliance Control Panels, Motor Control and PWM Applications, Battery-Powered IoT End Nodes, Embedded Educational and Training Platforms.
Arduino-Compatible Hobby and Prototyping Boards
The ATMEGA168-20AUR is the MCU at the heart of classic Arduino NG and Diecimila boards, where its 16 KB ISP flash, bootloader support, and 23 GPIO lines map directly to the documented Arduino pin mapping. Running the Arduino bootloader over UART, the chip self-programs its read-while-write flash so users upload sketches without a separate programmer. In this role the AVR architecture executes most instructions in a single clock cycle, giving predictable timing for digitalWrite and bit-banged protocols. Boards typically clock the chip at 16 MHz with a crystal on PB6/PB7, safely within the 20 MHz rating at 5V. The 10-bit ADC reads analog sensor shields, while USART handles serial monitor communication - making this part ideal for educational and rapid-prototyping designs.
Recommended
Industrial Sensor Nodes
In industrial sensor nodes, the ATMEGA168-20AUR combines its 8-channel 10-bit ADC with USART, SPI, and I2C interfaces to digitize analog transducers and stream readings over RS-485 or radio links. The industrial -40C to +85C temperature grade of the -20AUR suffix tolerates unheated cabinets and cold-chain environments, while 2.7V to 5.5V operation allows direct powering from 3.3V or 5V rails. The 512 B EEPROM stores calibration coefficients and node IDs across power cycles. Sleep modes and interrupt-driven wakeup keep average consumption low in battery-backed monitoring points. Its 20 MIPS throughput executes oversampling and digital filtering on-node, and debugWIRE permits in-system firmware updates through the same connector used for ISP, simplifying field maintenance.
Recommended
Consumer Appliance Control Panels
Appliance control panels - washers, cooktops, HVAC thermostats - use the ATMEGA168-20AUR for its balance of cost, I/O count, and analog integration. The 23 GPIO lines directly drive seven-segment displays, relays, and triac triggers, while three timer/counters generate PWM for heater and motor control and the 10-bit ADC reads NTC temperature sensors and user potentiometers. The 16 KB flash holds the full state machine and UI logic, and the 512 B EEPROM retains user settings such as temperature presets through power interruptions. Operating from an unregulated 5V derived from the mains supply, the wide 2.7-5.5V range absorbs supply sag. Watchdog timer support provides fail-safe recovery from code lockup, a common requirement in appliance safety compliance.
Recommended
Motor Control and PWM Applications
The ATMEGA168-20AUR suits small DC and stepper motor control through its three flexible timer/counters, which deliver multiple independent PWM channels with 8-bit or 16-bit resolution and phase-correct or fast PWM modes. At 20 MHz, PWM resolution reaches 8-bit at over 78 kHz, keeping switching out of audible range for fan and pump control. The 10-bit ADC feeds back current or position signals, and the AVR core's single-cycle execution closes control loops deterministically. Dead-time generation via output-compare units protects H-bridge drivers. Because the chip integrates everything needed - MCU, PWM, ADC, and communications for setpoint updates over USART or I2C - a single ATMEGA168-20AUR replaces a discrete controller-plus-peripheral solution in cost-sensitive drives.
Recommended
Battery-Powered IoT End Nodes
For battery-powered IoT end nodes, the ATMEGA168-20AUR's AVR sleep architecture offers idle, ADC-noise-reduction, power-save, and power-down modes with wakeup from interrupts. Designs that need deep sleep typically select the PA (picoPower) revision with the identical footprint, but the standard die still achieves long service life when the radio is the dominant load. The 1 KB SRAM buffers sensor frames, SPI drives sub-GHz or 2.4 GHz radios, and the 10-bit ADC samples battery voltage and sensors. 512 B EEPROM stores network credentials across deep-sleep cycles. Running from two AA cells (3V nominal) or a Li-SOCl2 cell, the wide 2.7-5.5V supply range and brown-out detector protect flash integrity as the battery discharges toward end of life.
Recommended
Embedded Educational and Training Platforms
Universities and training-kit vendors standardize on the ATMEGA168-20AUR because debugWIRE enables single-wire on-chip debugging with low-cost tools, and ISP allows students to program chips directly on the target board. The 133-instruction AVR assembly language is small enough for a full-semester architecture course, while C toolchains (AVR-GCC) demonstrate embedded software practice. The part exposes every fundamental subsystem on real pins: timers for lab exercises on PWM and interrupts, UART for serial protocol labs, ADC for data-acquisition experiments, and SPI/I2C for peripheral-driver assignments. The 20 MHz grade gives measurable performance-delta experiments when compared with slower speed grades, and abundant second-source supply (168A/PA/328P) keeps lab stock available worldwide.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA168-20AUR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA168A-AUR | ATMEGA168PA-AUR | ATMEGA328P-AUR | ATMEGA164PA-AUR |
|---|---|---|---|---|---|
| Package | 32-TQFP (7x7 mm) | 32-TQFP (7x7 mm) - same | 32-TQFP (7x7 mm) - same | 32-TQFP (7x7 mm) - same | 44-TQFP (10x10 mm) - larger |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 16 KB (8K x 16) | 16 KB | 16 KB | 32 KB | 16 KB |
| SRAM | 1 KB | 1 KB | 1 KB | 2 KB | 1 KB |
| Maximum Clock Speed | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| Supply Voltage | 2.7 V to 5.5 V | 2.7 V to 5.5 V | 1.8 V to 5.5 V (picoPower) | 1.8 V to 5.5 V (picoPower) | 1.8 V to 5.5 V (picoPower) |
| Temperature Range | -40C to +85C (industrial) | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C |
| I/O Pins | 23 | 23 | 23 | 23 | 32 |
Key Differentiators
- 20 MHz full-speed rating (vs ATMEGA165PA-AU)
- Newer-die migration path with identical footprint (vs ATMEGA168A-AUR)
- Flash headroom upgrade path (vs ATMEGA328P-AUR)
- Industrial temperature qualification (vs ATMEGA168-20AU)
Design Notes
Decouple each VCC pin (pins 4 and 6) with 100 nF ceramic capacitors placed within 5 mm of the pins, plus one 10 uF bulk capacitor per supply domain. Connect AVCC (pin 18) to VCC through an LC low-pass filter (e.g., 10 uH inductor and 100 nF) to keep ADC noise low - the Microchip datasheet requires AVCC to stay within 0.3V of VCC. Enable the internal brown-out detector at 2.7V via fuse bits so flash corruption is avoided during slow supply decay in battery designs.
When driving a parallel crystal on PB6/PB7, select a crystal with load capacitance matching the AVR's oscillator requirements and place the crystal within 10 mm of the pins with ground guard traces. For SPI buses on PB3-PB5, keep traces short and series-terminate near the driver if lines exceed 15 cm. RESET (pin 29) needs a 10 kOhm pull-up for reliable ISP programming; leaving it floating causes spurious resets in noisy industrial environments and can block debugWIRE sessions.
The 20 MHz rating applies only near 5V supply - below approximately 3V the safe maximum frequency derates per the frequency-versus-voltage curve in the manufacturer datasheet, so a 3.3V design should stay at or below roughly 13.3 MHz or use the internal 8 MHz RC oscillator. Also remember PC6 (pin 29) is RESET by default; reclaiming it as GPIO via the RSTDISBL fuse permanently disables ISP and high-voltage reprogramming is then required to recover the chip.
For ADC accuracy, route analog signals away from SPI and PWM traces and use a solid ground plane. AREF (pin 20) should be decoupled with 100 nF to ground when using the internal reference; never connect a voltage source to AREF while the internal reference is selected, as this can short the internal reference amplifier. When migrating to the pin-compatible ATMEGA168A/PA/328P, no PCB changes are needed - the footprints and pin functions are identical per Microchip migration notes.
Compliance Information
RoHS compliant per DigiKey product listing for ATMEGA168-20AUR. AEC-Q100 qualification not applicable to standard industrial ATmega parts.
