ATMEGA168A-MUR - 8-Bit AVR MCU 16KB Flash 20MHz | Microchip
MPN: ATMEGA168A-MUR β End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.5 | $2.50 |
| 10 | $2.24 | $22.40 |
| 100 | $2.05 | $205.00 |
| 500 | $1.92 | $960.00 |
| 1,000 | $1.85 | $1,850.00 |
ATMEGA168A-MUR Overview
An 8-bit AVR microcontroller is a single-chip computer that combines a RISC CPU core, non-volatile program memory, data memory, and integrated peripherals such as timers, serial interfaces, and analog-to-digital converters. Within the semiconductor taxonomy, the ATmega168A sits under 8-bit microcontrollers, which belong to the broader microcontroller unit (MCU) family, itself a subset of embedded processors and integrated circuits. The AVR architecture executes most instructions in a single clock cycle, giving roughly 20 MIPS at 20 MHz.
Key features include 16 KB of flash with read-while-write support, 512 B of EEPROM for non-volatile parameter storage, 1 KB of SRAM, 23 general-purpose I/O lines, 32 general-purpose working registers, and three flexible timer/counters with compare modes. The device integrates a byte-oriented two-wire serial interface, a programmable serial USART, and an SPI serial port, plus a 10-bit ADC and an internal calibrated oscillator.
The ATmega168A uses Microchip's high-performance, low-power AVR RISC architecture with 133 powerful instructions, most executing in a single clock cycle. The picoPower design keeps active and idle current low, and six sleep modes allow fine-grained power management. On-chip debug support via debugWIRE and in-system programming through SPI simplify development and field updates.
Typical applications include consumer appliances, battery chargers, sensor nodes, motor control front-ends, and industrial control boards. The 2.7 V to 5.5 V supply range and -40 C to +85 C operating window make it suitable for both 3.3 V and 5 V systems, and the 32-VQFN package saves board area compared with TQFP alternatives.
When designing with this device, decouple VCC and AVCC with 100 nF ceramic capacitors placed close to the pins, and keep the exposed pad soldered to a grounded thermal land. The reset pin should be pulled high through a 10 kOhm resistor, and the internal 8 MHz oscillator can eliminate an external crystal when 8 MHz accuracy is sufficient.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet, giving engineers a single reference for selection, replacement, and layout decisions.
Drop-in alternatives for ATMEGA168A-MUR 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-MUR (same form factor and footprint) β differing in Operating Temperature, Package, Supply Voltage Range, Program Memory Size, Connectivity.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATMEGA168PA-MU
β Drop-Inβ In Stock
$1.72 / Unit
View Datasheet βATMEGA88PA-MU
β Drop-Inπ Reference alternative (not in catalog)
ATMEGA328P-MU
β Drop-Inπ Reference alternative (not in catalog)
ATMEGA168-20MU
β Drop-Inβ In Stock
Contact for price
View Datasheet βATMEGA164PA-MUR
β Drop-Inβ In Stock
$2.89 / Unit
View Datasheet βATMEGA168A-MUR Maximum Ratings & Electrical Characteristics
| Core Processor | AVR |
| Core Size | 8-Bit |
| Maximum Clock Speed | 20 MHz |
| Program Memory Size | 16 KB (8K x 16) Flash |
| EEPROM Size | 512 B |
| SRAM Size | 1 KB |
| Supply Voltage Range | 2.7 V to 5.5 V |
| Operating Temperature | -40 C to +85 C |
| Number of I/O Lines | 23 |
| General Purpose Working Registers | 32 |
| Instruction Set | 133 powerful instructions, most single clock cycle |
| Connectivity | I2C, SPI, UART/USART |
| Timers/Counters | Three flexible timer/counters with compare modes |
| ADC Resolution | 10-bit |
| Package | 32-VQFN Exposed Pad (5x5 mm) |
| Mounting Type | Surface Mount |
| Packaging | Tape & Reel (TR) |
| Lifecycle Status | NRND (Not Recommended for New Designs) |
ATMEGA168A-MUR Pin Configuration
| Pin 1 | PD3 β Port D, bit 3 (also INT1, OC2B) |
| Pin 2 | PD4 β Port D, bit 4 (also T0, XCK) |
| Pin 3 | GND β Ground |
| Pin 4 | VCC β Digital supply voltage |
| Pin 5 | GND β Ground |
| Pin 6 | VCC β Digital supply voltage |
| Pin 7 | PB6 β Port B, bit 6 (also XTAL1/TOSC1) |
| Pin 8 | PB7 β Port B, bit 7 (also XTAL2/TOSC2) |
| Pin 9 | PD5 β Port D, bit 5 (also T1, OC0B) |
| Pin 10 | PD6 β Port D, bit 6 (also AIN0, OC0A) |
| Pin 11 | PD7 β Port D, bit 7 (also AIN1) |
| Pin 12 | PB0 β Port B, bit 0 (also ICP1, CLKO) |
| Pin 13 | PB1 β Port B, bit 1 (also OC1A) |
| Pin 14 | PB2 β Port B, bit 2 (also OC1B, SS) |
| Pin 15 | PB3 β Port B, bit 3 (also OC2A, MOSI) |
| Pin 16 | PB4 β Port B, bit 4 (also MISO) |
| Pin 17 | PB5 β Port B, bit 5 (also SCK) |
| Pin 18 | AVCC β Analog supply voltage for ADC |
| Pin 19 | ADC6 β Analog-to-digital converter input 6 |
| Pin 20 | AREF β Analog reference voltage |
| Pin 21 | GND β Ground |
| Pin 22 | ADC7 β Analog-to-digital converter input 7 |
| Pin 23 | PC0 β Port C, bit 0 (also ADC0) |
| Pin 24 | PC1 β Port C, bit 1 (also ADC1) |
| Pin 25 | PC2 β Port C, bit 2 (also ADC2) |
| Pin 26 | PC3 β Port C, bit 3 (also ADC3) |
| Pin 27 | PC4 β Port C, bit 4 (also ADC4, SDA) |
| Pin 28 | PC5 β Port C, bit 5 (also ADC5, SCL) |
| Pin 29 | PC6 β Port C, bit 6 (also RESET) |
| Pin 30 | PD0 β Port D, bit 0 (also RXD) |
| Pin 31 | PD1 β Port D, bit 1 (also TXD) |
| Pin 32 | PD2 β Port D, bit 2 (also INT0) |
| Pin 33 | EPAD β Exposed thermal pad, connect to ground |
Typical Applications
ATMEGA168A-MUR is suitable for 6 applications: Consumer Appliance Control, Battery Charger and Power Management, Industrial Sensor Node, Motor Control Front-End, Portable Instrumentation, Embedded Communication Gateway.
Consumer Appliance Control
The ATMEGA168A-MUR fits consumer appliance control because its 16 KB flash holds control firmware, user-interface logic, and safety routines, while 23 I/O lines drive relays, buttons, and LED indicators directly. Operating from 2.7 V to 5.5 V, it interfaces with 5 V relay drivers and 3.3 V sensors without level shifting. The 32-VQFN package saves board area in compact appliance panels. Three timer/counters generate PWM for buzzer tones and motor speed control, and the 10-bit ADC reads thermistors or potentiometers. Placed on a 5 V rail with 100 nF decoupling on VCC and AVCC, the device runs at 8 MHz from its internal oscillator, eliminating an external crystal and reducing BOM cost in high-volume white-goods production.
Recommended
Battery Charger and Power Management
The ATMEGA168A-MUR suits battery charger control because its 10-bit ADC monitors cell voltage and current sense amplifiers, while PWM outputs from the timer/counters regulate charge current in switch-mode topologies. The 2.7 V to 5.5 V supply allows direct operation from a regulated 3.3 V rail derived from the charger input. Six sleep modes let the controller enter power-down between charge cycles, reducing standby drain. 512 B EEPROM stores battery chemistry profiles and cycle counters without external memory. In a typical implementation the MCU samples a shunt resistor through an op-amp, adjusts a MOSFET gate driver via PWM, and reports status over UART. The 32-VQFN exposed pad helps dissipate heat when the controller shares a board with power components.
Recommended
Industrial Sensor Node
The ATMEGA168A-MUR works well in industrial sensor nodes because its -40 C to +85 C operating range and 2.7 V to 5.5 V supply tolerate the noisy rails and temperature swings of factory environments. The integrated 10-bit ADC digitizes analog sensor outputs, while I2C, SPI, and UART/USART connect digital sensors and field buses. 16 KB flash accommodates Modbus or custom protocol stacks, and 512 B EEPROM retains calibration coefficients across power cycles. In a typical node, the MCU polls a temperature or pressure sensor over I2C, filters readings in firmware, and transmits results over an RS-485 transceiver driven by the USART. The 32-VQFN package and exposed pad support compact DIN-rail modules with adequate thermal coupling to the enclosure.
Recommended
Motor Control Front-End
The ATMEGA168A-MUR is used as a motor control front-end because its three timer/counters generate complementary PWM channels for H-bridge or three-phase gate drivers, and the 20 MHz core provides enough bandwidth for commutation timing. The 10-bit ADC samples current shunts and back-EMF dividers, enabling closed-loop speed control. 23 I/O lines interface with hall sensors, limit switches, and fault inputs. Running from a 5 V rail, the device drives gate-driver ICs directly. In a typical design the MCU executes a PWM interrupt loop at 20 kHz, updates duty cycle from a PI controller, and monitors overcurrent through an analog comparator. The exposed-pad VQFN package improves thermal coupling when the controller sits near power stages.
Recommended
Portable Instrumentation
The ATMEGA168A-MUR suits portable instrumentation because it operates from 2.7 V to 5.5 V, allowing direct use of 3.3 V lithium or alkaline battery rails, and its six sleep modes extend runtime between measurements. The 10-bit ADC captures sensor signals, while the internal calibrated oscillator removes the need for an external crystal, saving board space and cost. 16 KB flash stores measurement algorithms and display drivers, and 512 B EEPROM logs calibration data. In a handheld meter, the MCU wakes on a button interrupt, samples the ADC, computes a filtered reading, updates an LCD over SPI, then returns to power-down. The 32-VQFN package keeps the instrument slim, and the exposed pad aids heat spreading near the display backlight driver.
Recommended
Embedded Communication Gateway
The ATMEGA168A-MUR serves as an embedded communication gateway because it integrates I2C, SPI, and UART/USART on one die, letting a single MCU bridge a local sensor bus to a host or fieldbus link. 16 KB flash holds protocol translation firmware, and 1 KB SRAM buffers packets between interfaces. The 20 MHz core handles bit-banged or hardware serial traffic at common baud rates without overrun. In a typical gateway, the device reads I2C sensor registers, formats the data, and forwards it over UART to a wireless module or RS-485 transceiver. The 2.7 V to 5.5 V range allows the MCU to match either 3.3 V or 5 V module logic. The 32-VQFN package supports compact gateway modules with the exposed pad tied to ground for noise immunity.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA168A-MUR β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA168PA-MU | ATMEGA88PA-MU | ATMEGA328P-MU | ATMEGA164PA-MU |
|---|---|---|---|---|---|
| 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 | 8 KB | 32 KB | 16 KB |
| SRAM | 1 KB | 1 KB | 1 KB | 2 KB | 1 KB |
| EEPROM | 512 B | 512 B | 512 B | 1 KB | 512 B |
| Maximum Clock Speed | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| Supply Voltage Range | 2.7 V to 5.5 V | 1.8 V to 5.5 V | 1.8 V to 5.5 V | 1.8 V to 5.5 V | 1.8 V to 5.5 V |
| Lifecycle Status | NRND | Active | Active | Active | Active |
| USART Interfaces | 1 | 1 | 1 | 1 | 2 |
Key Differentiators
- Tape-and-reel 32-VQFN packaging for automated assembly (vs ATMEGA168A-AU)
- 16 KB flash in a pin-compatible family (vs ATMEGA88PA-MU)
- Lower cost than the 32 KB sibling (vs ATMEGA328P-MU)
- Single USART with full peripheral set (vs ATMEGA164PA-MU)
Design Notes
Decouple both VCC and AVCC with 100 nF ceramic capacitors placed within a few millimeters of the pins, and add a 10 uF bulk capacitor on the board rail. AVCC must be connected even if the ADC is unused, and AREF should be bypassed with 100 nF when the internal reference is selected. Estimated: at 20 MHz and 5 V the core draws on the order of 10-15 mA, so a 100 nF local capacitor keeps supply ripple below the ADC noise floor.
Solder the 32-VQFN exposed pad to a grounded thermal land with at least four vias to the ground plane. The pad is the primary heat path and also the quiet ground reference for the ADC. Keep the crystal or resonator traces short and guard them with ground if an external clock source is used; otherwise enable the internal 8 MHz oscillator to free two pins and reduce BOM. Route analog inputs away from switching nodes.
Pull the RESET pin (PC6) high through a 10 kOhm resistor to VCC; leaving it floating causes random resets. Set the brown-out detector fuse to match your supply so flash writes are protected during power dips. When migrating from ATMEGA168A-MUR to ATMEGA168PA-MU, re-check the device signature and clock fuses in the programmer, because an incorrect fuse setting can lock the part or run it at the wrong frequency.
Compliance Information
Compliance data was not present in the verified web data for ATMEGA168A-MUR; values are set to unknown rather than assumed. The device is not an automotive AEC-Q100 qualified part. Confirm RoHS, REACH, and lead-free status with the Microchip product page or the distributor certificate of compliance before production.
