ATMEGA168PB-MU - 8-bit AVR MCU 16KB Flash 20MHz QFN-32 | Microchip
MPN: ATMEGA168PB-MU β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.85 | $1.85 |
| 10 | $1.68 | $16.80 |
| 100 | $1.52 | $152.00 |
| 500 | $1.4099 | $704.95 |
| 1,000 | $1.31 | $1,310.00 |
ATMEGA168PB-MU Overview
An 8-bit microcontroller is a single-chip computer that processes data in 8-bit words and integrates a CPU, memory, timers, and communication peripherals on one die. The ATmega168PB belongs to the AVR ATmega family of microcontrollers, part of the broader power-management hierarchy of embedded processors, and succeeds the ATmega168A/P generations with lower power and added peripherals. The picoPower technology and AVR enhanced RISC architecture execute most instructions in a single clock cycle, achieving throughputs approaching 1 MIPS per MHz.
Key features include 16 KB (8K x 16) self-programmable flash with read-while-write support, 512 B EEPROM, 1 KB SRAM, 27 general-purpose I/O lines, and 32 general-purpose working registers. Peripheral set comprises three flexible timers/counters with compare modes, a 10-bit ADC, a USART with wake-up on start condition, and two-wire interface (I2C) and SPI serial ports. The device operates from 1.8 V to 5.5 V over the industrial temperature range of -40C to +85C, and is classified by DigiKey as an AVR ATmega Functional Safety (FuSa) microcontroller IC.
Architecturally, the AVR core uses Harvard structure with separate program and data buses; the single-cycle instruction execution allows system designers to optimize power consumption versus processing speed, choosing slower clocks for battery life rather than lower supply voltage rails.
Typical applications include industrial sensor nodes, consumer appliances, battery-powered portable devices, and hobby/Arduino-compatible embedded systems, where the QFN/MLF footprint suits space-constrained, automated PCB assembly.
For design, verify pin functionality changes when migrating from ATmega48/88/168 to the PB generation, per Microchip application note MCU8APPS-456, since PB parts are drop-in for the 32-pin VFQFN only under stated conditions.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for ATMEGA168PB-MU 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 ATMEGA168PB-MU (same form factor and footprint) β differing in Package, Flash Memory, Supply Voltage Range, Operating Temperature, Core Processor.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
ATMEGA328PB-MU
β Drop-Inπ Reference alternative (not in catalog)
ATMEGA168PA-MU
β Drop-Inβ In Stock
$1.72 / Unit
View Datasheet βATMEGA168A-MU
β Drop-Inβ In Stock
$1.38 / Unit
View Datasheet βATMEGA168P-20MUR
β Drop-Inβ In Stock
$1.58 / Unit
View Datasheet βATMEGA88PB-MU
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
ATMEGA48PB-MU
β Drop-Inπ Reference alternative (not in catalog)
ATMEGA168PB-MU 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 |
| General Purpose I/O | 27 |
| Working Registers | 32 |
| Supply Voltage Range | 1.8 V to 5.5 V |
| Timers/Counters | 3 flexible timers/counters with compare modes |
| ADC Resolution | 10-bit |
| Connectivity | USART, SPI, I2C (Two-Wire Interface) |
| Operating Temperature | -40C to +85C (Industrial) |
| Package | 32-VFQFN (5x5 mm) with exposed pad |
| Mounting Type | Surface Mount |
| Technology | picoPower low-power CMOS |
| RoHS Status | Compliant (Green package) |
| Throughput | Approaching 1 MIPS per MHz |
ATMEGA168PB-MU Pin Configuration
| Pin 1 | PD3 β Port D bit 3 (GPIO / PCINT19) |
| Pin 2 | PD4 β Port D bit 4 (GPIO / PCINT20 / XCK / T0) |
| 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 (XTAL1 / TOSC1 / PCINT6) |
| Pin 8 | PB7 β Port B bit 7 (XTAL2 / TOSC2 / PCINT7) |
| Pin 9 | PD5 β Port D bit 5 (GPIO / PCINT21 / T1 / OC0B) |
| Pin 10 | PD6 β Port D bit 6 (GPIO / PCINT22 / AIN0 / OC0A) |
| Pin 11 | PD7 β Port D bit 7 (GPIO / PCINT23 / AIN1) |
| Pin 12 | PB0 β Port B bit 0 (GPIO / PCINT0 / ICP1 / CLKO) |
| Pin 13 | PB1 β Port B bit 1 (GPIO / PCINT1 / OC1A) |
| Pin 14 | PB2 β Port B bit 2 (GPIO / PCINT2 / SS / OC1B) |
| Pin 15 | PB3 β Port B bit 3 (GPIO / PCINT3 / MOSI / OC2A) |
| Pin 16 | PB4 β Port B bit 4 (GPIO / PCINT4 / MISO) |
| Pin 17 | PB5 β Port B bit 5 (GPIO / PCINT5 / SCK) |
| Pin 18 | AVCC β ADC supply voltage |
| Pin 19 | ADC6 β Analog input channel 6 |
| Pin 20 | ADC7 β Analog input channel 7 |
| Pin 21 | PC0 β Port C bit 0 (ADC0 / PCINT8) |
| Pin 22 | PC1 β Port C bit 1 (ADC1 / PCINT9) |
| Pin 23 | PC2 β Port C bit 2 (ADC2 / PCINT10) |
| Pin 24 | PC3 β Port C bit 3 (ADC3 / PCINT11) |
| Pin 25 | PC4 β Port C bit 4 (ADC4 / SDA / PCINT12) |
| Pin 26 | PC5 β Port C bit 5 (ADC5 / SCL / PCINT13) |
| Pin 27 | PC6 β RESET (active-low reset input) |
| Pin 28 | PD0 β Port D bit 0 (GPIO / PCINT16 / RXD) |
| Pin 29 | PD1 β Port D bit 1 (GPIO / PCINT17 / TXD) |
| Pin 30 | PD2 β Port D bit 2 (GPIO / PCINT18 / INT0) |
| Pin 31 | GND β Ground |
| Pin 32 | VCC β Digital supply voltage |
Typical Applications
ATMEGA168PB-MU is suitable for 6 applications: Industrial Sensor Nodes, Battery-Powered Portable Devices, Consumer Appliances and White Goods, Hobby and Arduino-Compatible Systems, Embedded Communication Interfaces, Motor Control and PWM Actuation.
Industrial Sensor Nodes
The ATMEGA168PB-MU fits industrial sensor nodes because its 1.8 V to 5.5 V supply range tolerates unregulated 3 V battery packs or noisy 5 V rails, while its industrial -40C to +85C rating covers factory-floor temperature swings. The 10-bit ADC digitizes thermistors, pressure bridges, and 4-20 mA conditioned signals directly, and the USART plus two-wire interface link to RS-485 transceivers or display drivers. In a typical node, the MCU spends most time in picoPower sleep modes, waking on comparator, external interrupt, or watchdog timeout, so average current drops to microamp levels. Its 16 KB flash holds sensor calibration tables and Modbus or custom protocol firmware with room to spare. Recommend 0.1 uF decoupling on VCC/AVCC and solid exposed-pad grounding for ADC accuracy.
Recommended
Battery-Powered Portable Devices
picoPower technology makes the ATMEGA168PB-MU well suited to battery-powered portable products such as remote controls, meters, and wearable accessories. Operating directly from two alkaline cells (3 V) or a lithium coin cell (3 V) within the 1.8 V to 5.5 V range eliminates a regulator stage, saving board area and quiescent drain. Power-down and power-save modes reduce current to sub-microamp levels while the asynchronous timer keeps RTC functions alive, and the USART wake-up on start-condition feature lets the device sleep until an external event arrives. The 20 MHz capability is available when running on 5 V for burst processing, while 1 MHz internal oscillator modes stretch battery life at 3 V. Designers should measure real sleep current with all unused GPIO defined as inputs with pull-ups disabled, a common pitfall that inflates standby drain several-fold.
Recommended
Consumer Appliances and White Goods
The ATMEGA168PB-MU serves appliance control boards where cost, robustness, and code space balance: 16 KB flash accommodates button debouncing, LED or LCD driving, motor relay sequencing, and fault-logging code, while 1 KB SRAM supports small state machines. The three timers with compare modes generate PWM for fan, heater, or dimmer control, and the 10-bit ADC reads NTC temperature sensors and user potentiometers. The 32-VFQFN (5x5 mm) surface-mount package supports automated assembly, and its Green RoHS package meets global appliance environmental requirements. Its industrial temperature rating handles enclosure interiors that exceed consumer-grade limits. DigiKey classifies the device as a Functional Safety (FuSa) MCU, which supports appliance safety workflows. Use the watchdog timer and brown-out detector enabled by fuse settings for power-dip resilience in mains-powered environments.
Recommended
Hobby and Arduino-Compatible Systems
The ATMEGA168PB-MU is Arduino-compatible through the MiniCore and XMiniCore community hardware packages, and Microchip's ATmega168PB Xplained Mini kit provides an official Arduino Uno form-factor evaluation platform. The 16 KB flash is sufficient for typical sketches using Serial, I2C (Wire), and SPI libraries, with the caveat that large sketches may need optimization versus 32 KB ATmega328 boards. The AVR toolchain - Atmel Studio / Microchip Studio, avr-gcc, and avrdude - supports ISP programming through the standard 6-pin header, so existing UNO-style programming hardware works unchanged. Its PB-generation peripherals (extra timer and pin-function options) benefit advanced users while remaining transparent to Arduino API code. For prototypes, pair with a USB-serial bridge and rely on the internal 8 MHz oscillator to omit the external crystal in space-constrained builds.
Recommended
Embedded Communication Interfaces
With USART, SPI, and two-wire interface (I2C) on board, the ATMEGA168PB-MU acts as a protocol bridge or companion controller in systems where a main processor needs offloading. The USART with wake-on-start-condition enables low-power listening for LIN-style or custom serial links; SPI runs sensor or flash devices at high clock rates; and the two-wire interface supports multi-drop peripheral networks with addressing. The PB generation's additional timer resources support precise baud-rate generation and software protocol timing. Running at 5 V provides TTL-level noise margin for cable runs, while 3.3 V operation interfaces directly with modern logic. The 27 GPIO lines cover chip-selects, direction control, and status handshakes without external expanders. Firmware volume for UART buffers, CRC routines, and command parsers fits comfortably in the 16 KB flash with 1 KB SRAM for buffering.
Recommended
Motor Control and PWM Actuation
The ATMEGA168PB-MU's three flexible timers/counters with compare modes generate multiple hardware PWM channels for small DC motor, servo, fan, and LED actuation tasks. At 20 MHz, 8-bit PWM resolution is available at roughly 78 kHz carrier, above audible range for fan and pump control, while slower carriers suit hobby servos and H-bridge drive. The 10-bit ADC reads back current-sense or potentiometer feedback for closed-loop speed control, and external interrupts handle encoder or zero-cross inputs. The 1.8 V to 5.5 V range matches single-cell or USB-powered actuators, and the industrial temperature rating covers enclosed driver boards. Flash space of 16 KB accommodates PID control, ramp profiles, and fault handling. When driving inductive loads, use freewheeling diodes on the external power stage - the MCU GPIO itself must remain within its absolute maximum ratings.
Recommended
Recommended Products Summary
Engineering reference data for ATMEGA168PB-MU β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ATMEGA328PB-MU | ATMEGA168PA-MU | ATMEGA88PB-MU | ATMEGA48PB-MU |
|---|---|---|---|---|---|
| Package | 32-VFQFN (5x5 mm) with EP | 32-VFQFN (5x5 mm) - same | 32-VFQFN/MLF (5x5 mm) - same | 32-VFQFN (5x5 mm) - same | 32-VFQFN (5x5 mm) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 16 KB (8K x 16) | 32 KB (16K x 16) | 16 KB (8K x 16) | 8 KB (4K x 16) | 4 KB (2K x 16) |
| SRAM | 1 KB | 2 KB | 1 KB | 512 B | 256 B |
| EEPROM | 512 B | 1 KB | 512 B | 256 B | 256 B |
| Max Clock Speed | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| Supply Voltage | 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 | 1.8 V to 5.5 V |
| Peripheral Set | 3 timers, 10-bit ADC, USART, SPI, TWI | More timers, 2x USART, 2x TWI, 2x SPI (PB additions) | 3 timers, 10-bit ADC, USART, SPI, TWI (PA set) | Reduced timer/serial set vs 168PB | Reduced timer/serial set vs 168PB |
| Operating Temperature | -40C to +85C (Industrial) | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C |
Key Differentiators
- Double the memory at the same footprint (vs ATMEGA328PB-MU)
- Lower power and more peripherals than the PA generation (vs ATMEGA168PA-MU)
- Balanced memory sizing for mid-range firmware (vs ATMEGA88PB-MU)
- Cost floor with same pinout (vs ATMEGA48PB-MU)
Design Notes
The 32-VFQFN exposed pad is the primary ground connection and must be soldered to a PCB thermal land with an array of thermal vias to the ground plane. QFN center-pad voiding during reflow is a common yield problem: use a divided solder-paste pattern (typically 60-70% coverage across 4-6 apertures) rather than one large paste block. Follow Microchip's QFN land-pattern recommendations, and treat the MLF-to-VFQFN footprint equivalence described in application note MCU8APPS-456 when migrating legacy ATmega168 layouts.
Decouple both VCC pins (pins 4, 6, 32) and AVCC (pin 18) with 0.1 uF ceramics placed within 2-3 mm of each pin, plus one 4.7-10 uF bulk capacitor per supply domain. Tie AVCC to VCC through a low-pass LC filter (e.g., 10 uH + 10 uF) when ADC accuracy matters, and never leave AVCC unconnected even if the ADC is unused. Enable the internal brown-out detector via fuses for battery applications, since SRAM corruption below the minimum operating voltage is the most common field failure on AVR designs.
When migrating from ATmega168/168A/168PA to the PB version, review the Added/Modified Pin Functionality chapter of application note MCU8APPS-456 before reusing the PCB - PB parts are drop-in for the 32-pin VFQFN only under stated conditions, and some pins carry additional analog functions. Also note that PC6 (pin 27) is dedicated RESET on this pinout: enable the external-reset fuse or add an optional pull-up (10k) to VCC, since a floating reset pin causes sporadic boot failures that are difficult to diagnose.
Estimated: at 5 V and 20 MHz with all peripherals active, the ATmega168PB draws on the order of 10-15 mA of dynamic current (about 50-75 mW), which produces a junction rise well under 5 C over a typical land pattern given the exposed-pad thermal path - no heatsinking is required. Thermal design attention is instead justified only when many GPIO pins source near-maximum current simultaneously; in that case, verify per-pin and total device current limits against the datasheet absolute maximum table.
Compliance Information
Green RoHS-compliant package per Mouser (QFN/MLF GRN 5V) and LCSC listing. DigiKey additionally classifies the part as a Functional Safety (FuSa) microcontroller. REACH and conflict-minerals statements not found in provided data.
