ATMEGA168P-20MUR - 8-Bit AVR MCU 20MHz 16KB Flash | Microchip
MPN: ATMEGA168P-20MUR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.65 | $2.65 |
| 10 | $2.38 | $23.80 |
| 100 | $2.05 | $205.00 |
| 500 | $1.82 | $910.00 |
| 1,000 | $1.58 | $1,580.00 |
ATMEGA168P-20MUR Overview
An 8-bit AVR ATmega microcontroller is a member of the AVR family of modified Harvard-architecture RISC processors, positioned in the system hierarchy as: ATmega168P -> ATmega family -> 8-bit AVR MCU -> microcontroller -> embedded processor. AVRs execute most instructions in a single clock cycle, which is why a 20 MHz ATmega168P achieves up to 20 MIPS - roughly 1 MIPS per MHz, higher effective throughput than many competing 8-bit cores at the same clock rate.
Key features include the picoPower low-power technology with multiple sleep modes and sub-uA power-down current, a 10-bit ADC with up to 8 channels, three flexible timers (two 8-bit, one 16-bit with compare modes and PWM), a full-duplex USART, two-wire interface (I2C-compatible), SPI, and debugWIRE on-chip debugging. The part operates from 2.7 V to 5.5 V and is rated for the industrial temperature range of -40C to +85C, with the -20M speed grade valid at 4.5 V to 5.5 V.
Architecturally, the device combines 32 general-purpose working registers directly connected to the ALU, allowing one-cycle execution of powerful instructions, and read-while-write FLASH for reliable in-system self-programming via the bootloader capability.
Typical applications include Arduino-compatible boards (the ATmega168 is the classic Duemilanove-class core), industrial sensor nodes, consumer appliance controls, battery-powered picoPower designs, and motor/PWM control where the three timers and 6 PWM channels are valuable.
Design consideration: choose the VCC operating point carefully - full 20 MHz operation requires 4.5 V to 5.5 V; at 2.7 V to 4.5 V the clock must be derated to 10 MHz per the AVR frequency-voltage curve.
This page synthesizes distributor pricing, drop-in same-footprint alternatives, pinout, and practical design notes not consolidated in the manufacturer datasheet. Pricing shown is as of 2026-09-16.
Drop-in alternatives for ATMEGA168P-20MUR — 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 ATMEGA168P-20MUR (same form factor and footprint) — differing in Operating Temperature, Package, Lifecycle Status, ADC Channels, Connectivity.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ATMEGA168A-MUR
✅ Drop-In✓ In Stock
$1.85 / Unit
View Datasheet →ATMEGA168A-MU
✅ Drop-In✓ In Stock
$1.38 / Unit
View Datasheet →ATMEGA168-20MUR
✅ Drop-In✓ In Stock
$2.12 / Unit
View Datasheet →ATMEGA168-20MU
✅ Drop-In✓ In Stock
Contact for price
View Datasheet →ATMEGA168P-20MU
✅ Drop-In📋 Reference alternative (not in catalog)
ATMEGA168P-20MUR Maximum Ratings & Electrical Characteristics
| Core Processor | AVR |
| Core Size | 8-Bit |
| Speed | 20 MHz |
| Flash Memory | 16 KB (8K x 16) |
| EEPROM | 512 B |
| SRAM | 1 KB |
| Supply Voltage Range | 2.7 V to 5.5 V |
| Number of I/O | 23 |
| ADC Resolution | 10-bit |
| ADC Channels | 8 |
| Timers | 2 x 8-bit, 1 x 16-bit |
| Communication Interfaces | USART, SPI, I2C (TWI) |
| PWM Channels | 6 |
| Operating Temperature | -40C to +85C (Industrial) |
| Package | 32-VQFN (5x5 mm) Exposed Pad |
| Mounting Type | Surface Mount |
| Low-Power Technology | picoPower |
| On-Chip Debug | debugWIRE |
| Programming | ISP (In-System Programming), ICSP |
| RoHS Status | Compliant (GREEN) |
ATMEGA168P-20MUR Pin Configuration
| Pin 1 | PD3 (PCINT19/OC2B/INT1) — Port D bit 3, pin change interrupt / PWM output / external interrupt 1 |
| Pin 2 | PD4 (PCINT20/XCK/T0) — Port D bit 4, pin change interrupt / USART external clock / Timer0 clock input |
| Pin 3 | GND — Ground |
| Pin 4 | VCC — Digital supply voltage |
| Pin 5 | GND — Ground |
| Pin 6 | VCC — Digital supply voltage |
| Pin 7 | PB6 (PCINT6/XTAL1/TOSC1) — Port B bit 6, crystal oscillator input 1 / timer oscillator |
| Pin 8 | PB7 (PCINT7/XTAL2/TOSC2) — Port B bit 7, crystal oscillator output 2 |
| Pin 9 | PD5 (PCINT21/OC0B/T1) — Port D bit 5, pin change interrupt / PWM output / Timer1 clock input |
| Pin 10 | PD6 (PCINT22/OC0A/AIN0) — Port D bit 6, pin change interrupt / PWM output / analog comparator input |
| Pin 11 | PD7 (PCINT23/AIN1) — Port D bit 7, pin change interrupt / analog comparator input |
| Pin 12 | PB0 (PCINT0/CLKO/ICP1) — Port B bit 0, pin change interrupt / clock output / Timer1 input capture |
| Pin 13 | PB1 (PCINT1/OC1A) — Port B bit 1, pin change interrupt / 16-bit Timer1 PWM output A |
| Pin 14 | PB2 (PCINT2/SS/OC1B) — Port B bit 2, pin change interrupt / SPI slave select / PWM output B |
| Pin 15 | PB3 (PCINT3/OC2A/MOSI) — Port B bit 3, PWM output / SPI master data out |
| Pin 16 | PB4 (PCINT4/MISO) — Port B bit 4, pin change interrupt / SPI master data in |
| Pin 17 | PB5 (PCINT5/SCK) — Port B bit 5, pin change interrupt / SPI clock (also ICSP programming) |
| Pin 18 | AVCC — ADC supply voltage (connect to VCC through LC filter) |
| Pin 19 | ADC6 — ADC input channel 6 (QFN package only) |
| Pin 20 | AREF — Analog reference for ADC, decouple to GND |
| Pin 21 | GND — Ground |
| Pin 22 | ADC7 — ADC input channel 7 (QFN package only) |
| Pin 23 | PC0 (PCINT8/ADC0) — Port C bit 0, pin change interrupt / ADC channel 0 |
| Pin 24 | PC1 (PCINT9/ADC1) — Port C bit 1, pin change interrupt / ADC channel 1 |
| Pin 25 | PC2 (PCINT10/ADC2) — Port C bit 2, pin change interrupt / ADC channel 2 |
| Pin 26 | PC3 (PCINT11/ADC3) — Port C bit 3, pin change interrupt / ADC channel 3 |
| Pin 27 | PC4 (PCINT12/SDA/ADC4) — Port C bit 4, TWI data line / ADC channel 4 |
| Pin 28 | PC5 (PCINT13/SCL/ADC5) — Port C bit 5, TWI clock line / ADC channel 5 |
| Pin 29 | PC6 (PCINT14/RESET) — Reset input (active low) / pin change interrupt; debugWIRE line |
| Pin 30 | PD0 (PCINT16/RXD) — Port D bit 0, USART receive data |
| Pin 31 | PD1 (PCINT17/TXD) — Port D bit 1, USART transmit data |
| Pin 32 | PD2 (PCINT18/INT0) — Port D bit 2, external interrupt 0 |
Typical Applications
ATMEGA168P-20MUR is suitable for 6 applications: Arduino-Compatible Hobby and Education Boards, Battery-Powered Sensor Nodes, Industrial Motor and PWM Control, Appliance and Consumer Controls, USB Serial Bridge and Communications Adapters, Analog Data Acquisition Front Ends.
Arduino-Compatible Hobby and Education Boards
The ATMEGA168P-20MUR is the classic 8-bit AVR core behind Arduino Duemilanove-class boards, and it remains fully supported by the Arduino IDE and bootloader ecosystem. With an external 16 MHz crystal the part delivers 16 MIPS through the AVR single-cycle instruction core, and its 16 KB FLASH accommodates the Arduino optiboot bootloader plus typical sketches. The 23 GPIO lines map directly to the standard Arduino UNO-style pinout, including the six PWM outputs used by analogWrite(). For makers and educators, the part's debugWIRE support and ICSP header provide a path from hobby programming to professional in-circuit debugging on the same hardware.
Recommended
Battery-Powered Sensor Nodes
The picoPower technology of the ATMEGA168P-20MUR makes it a strong fit for battery-operated sensor nodes that spend most of their life asleep. In power-down mode the AVR core stops while the pin-change and watchdog interrupts remain armed as wake sources, letting the node sample with the 10-bit ADC and then return to sleep at a very low duty cycle. The 2.7 V supply floor allows direct operation from two alkaline cells or a Li-Ion cell with an LDO. Designers should budget the external pull-ups and sensor standby currents into the sleep budget, since these often dominate over the MCU core current.
Recommended
Industrial Motor and PWM Control
With three flexible timers and six PWM channels, the ATMEGA168P-20MUR handles small motor, LED dimming, and actuator control tasks in industrial equipment. The 16-bit Timer/Counter1 provides phase-correct or fast PWM at up to 16-bit resolution, while the two 8-bit timers handle scheduling and complementary PWM duties. Running at 5 V gives 20 MHz full-speed operation and robust 5 V-tolerant I/O for driving MOSFET gate drivers or optocoupler inputs in electrically noisy environments. The industrial -40C to +85C rating covers factory-floor ambient conditions without derating beyond the standard AVR frequency-voltage curve.
Recommended
Appliance and Consumer Controls
Consumer appliances need a low-cost MCU with a user interface (buttons, LEDs, buzzer), simple serial links, and a watchdog for field reliability - all areas where the ATMEGA168P-20MUR excels. The USART supports host communication or external module interfacing, TWI drives small OLED or EEPROM peripherals, and the internal RC oscillator can eliminate the crystal for cost-sensitive boards that do not need precise timing. The 1 KB SRAM comfortably holds a small state machine plus display buffers, and the 512 B EEPROM retains calibration and user settings through power cycles, reducing external memory BOM cost.
Recommended
USB Serial Bridge and Communications Adapters
The full-duplex USART of the ATMEGA168P-20MUR supports baud rates up to 1 Mbps clocked from 20 MHz, making it usable in protocol-translation adapters and legacy serial links. Paired with a USB-to-UART bridge upstream, the AVR can implement custom framing, checksums, and command interpreters between a PC and industrial devices. The SPI and TWI masters let one bridge serve multiple slave peripherals. Designers should use an external crystal rather than the internal RC oscillator when precise UART baud timing is required, as baud error must stay within the USART tolerance budget.
Recommended
Analog Data Acquisition Front Ends
The 10-bit, 8-channel ADC with internal 1.1 V / 2.56 V references (per the ATmega168P family datasheet) lets the ATMEGA168P-20MUR form a compact acquisition front end for thermistors, potentiometers, and ratiometric sensors. AVCC (pin 18) powers the ADC and should be filtered with an LC network for noise performance, while AREF (pin 20) supports external reference decoupling. The extra ADC6/ADC7 inputs available only on the QFN package are a key reason to choose the 32-VQFN over TQFP/PDIP variants in this part family. Interrupt-driven conversions free the CPU for filtering and storage tasks.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA168P-20MUR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA168A-MUR | ATMEGA168A-MU | ATMEGA168-20MUR | ATMEGA168-20MU |
|---|---|---|---|---|---|
| Package | 32-VQFN (5x5 mm) | 32-VQFN (5x5 mm) - same | 32-VQFN (5x5 mm) - same | 32-VQFN (5x5 mm) - same | 32-VQFN (5x5 mm) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 16 KB | 16 KB | 16 KB | 16 KB | 16 KB |
| SRAM | 1 KB | 1 KB | 1 KB | 1 KB | 1 KB |
| 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 (A-series wide range) | 1.8 V to 5.5 V | 2.7 V to 5.5 V | 2.7 V to 5.5 V |
| Low-Power Feature | picoPower die | picoPower-equivalent A die | picoPower-equivalent A die | original die, higher power-down current | original die, higher power-down current |
| Packaging | Tape & Reel | Tape & Reel | Tray | Tape & Reel | Tray |
Key Differentiators
- picoPower low-power die (vs ATMEGA168-20MUR)
- QFN-only extra ADC channels (vs ATMEGA168P-20AU (TQFP))
- Cost-memory trade-off vs 328P (vs ATMEGA328P-AU)
Design Notes
Decouple both VCC pins (4 and 6) and AVCC (pin 18) individually with 100 nF ceramics placed within 2-3 mm of each pad, plus a 10 uF bulk capacitor near the supply entry. Tie AVCC to VCC through a 10 uH inductor and 100 nF capacitor when ADC accuracy is important; never leave AVCC unconnected even if the ADC is unused (connect directly to VCC). Estimated: at 20 MHz and 5 V, active current is roughly 10-15 mA per AVR family datasheet typical values, so a linear regulator supplying the MCU alone dissipates well under 100 mW - no thermal concerns for the MCU itself.
The 32-VQFN exposed pad must be soldered to a grounded copper pour; use a 3x3 via array under the pad to tie it to the ground plane. VQFN pads require slightly enlarged PCB lands (typical +0.1 mm per side) to accommodate the fillet for reliable reflow and rework. Follow the Microchip AVR hardware design application note guidance for crystal layout: keep XTAL1/XTAL2 traces short (under 10 mm), guard with ground, and place load capacitors directly adjacent to pins 7 and 8.
The most frequent ATmega168P pitfalls: (1) running 20 MHz below 4.5 V violates the frequency-voltage curve - derate to 10 MHz at 3.3 V; (2) the RESET pin (pin 29) doubles as the debugWIRE line, so an external pull-up of 10 kOhm plus a series resistor are needed if ISP and debugWIRE coexist; (3) PC5/PC4 are used as I2C when TWI is enabled - external pull-ups of 4.7 kOhm are mandatory since TWI does not activate internal pull-ups in host mode; (4) ADC6/ADC7 exist only on QFN packages - firmware ported from DIP parts must not reference them unless the package is confirmed.
Compliance Information
Classified GREEN per Microchip/distributor data, indicating lead-free and halogen-free. REACH and conflict minerals statements not found in provided data - request from Microchip environmental portal.
