ATMEGA168A-MMHR - 8-Bit AVR MCU 16KB Flash 20MHz | Microchip
MPN： ATMEGA168A-MMHR ✓ 啟用中ATMEGA168A-MMHR 概覽
An AVR microcontroller is a Harvard-architecture 8-bit RISC device that executes most instructions in a single clock cycle. Within the product hierarchy, the ATmega168A sits under AVR 8-bit MCUs, then microcontrollers (MCU), then embedded processors and integrated circuits. The ATmega168A family is the mid-density member of the classic ATmega48/88/168/328 pin-compatible line, sharing the same 28-pin footprint and peripheral set so firmware can scale between memory densities without PCB changes.
Key features include 16 KB flash with read-while-write, 512 B EEPROM for non-volatile parameter storage, 1 KB SRAM, 23 general-purpose I/O lines, 32 general-purpose working registers, and three flexible timers (two 8-bit, one 16-bit) with PWM. Peripherals include a 10-bit ADC, USART, SPI, and TWI (I2C) interfaces, plus an internal 8 MHz calibrated RC oscillator that removes the need for an external clock in many designs.
The device uses Microchip's low-power AVR core with picoPower technology, supporting multiple sleep modes for battery operation. The 28-VQFN (4x4 mm) package with exposed pad provides a compact footprint for portable and wearable electronics while retaining the full 23 I/O lines of the larger TQFP-32 variant.
Typical applications include Arduino-compatible development boards, battery-powered sensor nodes, motor control, and industrial automation front-ends. The 1.8 V to 5.5 V range allows direct operation from single-cell Li-Ion or 3.3 V/5 V rails.
When designing, decouple VCC and AVCC with 100 nF ceramic capacitors placed close to the pins, and connect the exposed pad to ground for thermal and noise performance. This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
直接替換替代品，適用於 ATMEGA168A-MMHR — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
此系列的變體
與下列產品可直接替換的同系列型號： ATMEGA168A-MMHR （相同外形與佔位） — 差異在於 Package, EEPROM, Instruction Set, SRAM, Flash Memory.
ATMEGA168A-MMH
✅ 直接替換📋 參考替代品（不在目錄中）
ATMEGA88A-MMHR
✅ 直接替換聯絡詢價
查看資料表 →ATMEGA48A-MMHR
✅ 直接替換聯絡詢價
查看資料表 →ATMEGA328P-MMHR
✅ 直接替換聯絡詢價
查看資料表 →ATMEGA168PA-MMHR
✅ 直接替換📋 參考替代品（不在目錄中）
ATMEGA168A-MMHR 最大額定值與電氣特性
| Core Architecture | 8-bit AVR RISC |
| Program Memory | 16 KB Flash (8K x 16) |
| EEPROM | 512 B |
| SRAM | 1 KB |
| 最大時脈頻率 | 20 MHz |
| Operating Voltage | 1.8 V to 5.5 V |
| Throughput | Up to 20 MIPS at 20 MHz |
| General Purpose I/O | 23 lines |
| General Purpose Registers | 32 (8-bit) |
| Timers | Two 8-bit, one 16-bit with PWM |
| ADC | 10-bit successive approximation |
| Communication Interfaces | USART, SPI, TWI (I2C) |
| Internal Oscillator | 8 MHz calibrated RC |
| 封裝 | 28-VQFN (4x4 mm) with exposed pad |
| 安裝類型 | Surface Mount |
| 工作溫度 | -40 C to +85 C |
| Instruction Set | 133 powerful instructions, most single-cycle |
| RoHS 狀態 | Compliant |
ATMEGA168A-MMHR 腳位配置
| 腳位 1 | PD3 — Port D, bit 3 / INT1 / OC2B |
| 腳位 2 | PD4 — Port D, bit 4 / T0 / XCK |
| 腳位 3 | GND — Ground |
| 腳位 4 | VCC — Digital supply voltage |
| 腳位 5 | GND — Ground |
| 腳位 6 | VCC — Digital supply voltage |
| 腳位 7 | PB6 — Port B, bit 6 / XTAL1 / TOSC1 |
| 腳位 8 | PB7 — Port B, bit 7 / XTAL2 / TOSC2 |
| 腳位 9 | PD5 — Port D, bit 5 / T1 / OC0B |
| 腳位 10 | PD6 — Port D, bit 6 / AIN0 / OC0A |
| 腳位 11 | PD7 — Port D, bit 7 / AIN1 |
| 腳位 12 | PB0 — Port B, bit 0 / ICP1 / CLKO |
| 腳位 13 | PB1 — Port B, bit 1 / OC1A |
| 腳位 14 | PB2 — Port B, bit 2 / SS / OC1B |
| 腳位 15 | PB3 — Port B, bit 3 / MOSI / OC2A |
| 腳位 16 | PB4 — Port B, bit 4 / MISO |
| 腳位 17 | PB5 — Port B, bit 5 / SCK |
| 腳位 18 | AVCC — Analog supply voltage |
| 腳位 19 | ADC6 — Analog input channel 6 |
| 腳位 20 | AREF — Analog reference voltage |
| 腳位 21 | GND — Ground |
| 腳位 22 | ADC7 — Analog input channel 7 |
| 腳位 23 | PC0 — Port C, bit 0 / ADC0 |
| 腳位 24 | PC1 — Port C, bit 1 / ADC1 |
| 腳位 25 | PC2 — Port C, bit 2 / ADC2 |
| 腳位 26 | PC3 — Port C, bit 3 / ADC3 |
| 腳位 27 | PC4 — Port C, bit 4 / ADC4 / SDA |
| 腳位 28 | PC5 — Port C, bit 5 / ADC5 / SCL |
典型應用
ATMEGA168A-MMHR 適用於 6 應用s: Arduino-Compatible Development Boards, Battery-Powered Sensor Nodes, Motor Control and Robotics, Industrial Automation Front-Ends, Consumer Electronics Control, Embedded Data Logging.
Arduino-Compatible Development Boards
The ATMEGA168A-MMHR fits Arduino-compatible development boards because it is the same 8-bit AVR core used on classic Arduino hardware, with 16 KB flash and 1 KB SRAM sufficient for the bootloader plus typical sketches. The 28-pin VQFN (4x4 mm) package provides 23 I/O lines, enough for digital and analog headers, while the internal 8 MHz RC oscillator allows operation without an external crystal in cost-reduced variants. The MiniCore Arduino hardware package explicitly supports the ATmega168 family, so toolchain support is mature. A trade-off is that the VQFN package requires reflow soldering and is harder to hand-prototype than the TQFP-32 ATMEGA168A-AU, so it suits production boards rather than breadboard builds.
推薦
Battery-Powered Sensor Nodes
The ATMEGA168A-MMHR suits battery-powered sensor nodes because it operates from 1.8 V to 5.5 V, allowing direct connection to a single-cell Li-Ion battery without a boost converter, and its AVR core supports multiple sleep modes for low average current. The 10-bit ADC samples analog sensors such as thermistors or photodiodes, while the TWI (I2C) interface connects digital sensors and the USART handles wireless module communication. With 16 KB flash and 1 KB SRAM, the device can run sensor fusion and radio stack firmware without external memory. The main trade-off is that at 1.8 V the maximum clock is reduced, so designers must balance throughput against battery life when selecting the operating point.
推薦
Motor Control and Robotics
The ATMEGA168A-MMHR is used in motor control and robotics because its three timers, including a 16-bit timer with PWM, generate the precise pulse-width modulation signals required for H-bridge and servo control. The 23 general-purpose I/O lines drive direction pins, limit switches, and encoder inputs, while the 10-bit ADC reads current-sense shunts for overcurrent detection. At 20 MHz the core delivers up to 20 MIPS, enough for a simple PID loop running alongside communication tasks. The 1.8 V to 5.5 V range allows direct interfacing with 5 V motor drivers or 3.3 V logic. A design consideration is that PWM jitter must be minimized by using hardware timers rather than software loops, especially when driving multiple motors.
推薦
Industrial Automation Front-Ends
The ATMEGA168A-MMHR serves industrial automation front-ends where a compact microcontroller handles sensor polling, relay sequencing, and serial communication. The 28-pin VQFN (4x4 mm) package saves board area on dense I/O modules, while the -40 C to +85 C operating range covers most factory environments. USART, SPI, and TWI interfaces connect to industrial sensors, display drivers, and host controllers, and the 512 B EEPROM stores calibration constants without external memory. The 5.5 V maximum supply allows direct operation from a regulated 5 V backplane rail. A trade-off is that the device is not AEC-Q100 qualified, so it is unsuitable for automotive under-hood applications; for those, an automotive-grade MCU should be selected instead.
推薦
Consumer Electronics Control
The ATMEGA168A-MMHR is used in consumer electronics control because it provides a complete 8-bit MCU with 16 KB flash, 23 I/O lines, and integrated USART, SPI, and TWI in a 4x4 mm package that fits small enclosures. It can manage button matrices, LED indicators, and capacitive touch sensing while communicating with a main processor over I2C or UART. The internal 8 MHz RC oscillator reduces bill-of-materials cost by eliminating the external crystal in non-timing-critical designs. The 1.8 V to 5.5 V range supports both 3.3 V and 5 V system rails. A design consideration is that the internal oscillator has limited accuracy over temperature, so an external crystal should be added when precise UART baud rates or real-time clocks are required.
推薦
Embedded Data Logging
The ATMEGA168A-MMHR supports embedded data logging because its 512 B EEPROM stores configuration and calibration data across power cycles, while the 16 KB flash holds logging firmware and the 1 KB SRAM buffers samples before writing to external memory. The 10-bit ADC digitizes analog inputs, and the SPI interface connects SD cards or serial flash for bulk storage. The 1.8 V to 5.5 V range allows the logger to run from a 3.3 V rail or directly from a Li-Ion cell. At 20 MHz the core can timestamp and compress samples in real time. A trade-off is that 1 KB SRAM limits in-RAM buffering, so designs with high sample rates should stream data to external memory rather than buffering large blocks internally.
推薦
推薦產品摘要
工程參考資料，適用於 ATMEGA168A-MMHR — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 | ATMEGA168A-MMH | ATMEGA88A-MMHR | ATMEGA48A-MMHR | ATMEGA328P-MMHR | ATMEGA168PA-MMHR |
|---|---|---|---|---|---|---|
| Package | 28-VQFN (4x4 mm) | 28-VQFN (4x4 mm) - same | 28-VQFN (4x4 mm) - same | 28-VQFN (4x4 mm) - same | 28-VQFN (4x4 mm) - same | 28-VQFN (4x4 mm) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 16 KB | 16 KB | 8 KB | 4 KB | 32 KB | 16 KB |
| SRAM | 1 KB | 1 KB | 512 B | 512 B | 2 KB | 1 KB |
| EEPROM | 512 B | 512 B | 512 B | 256 B | 1 KB | 512 B |
| Maximum Clock | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| Operating 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 | 1.8 V to 5.5 V |
| General Purpose I/O | 23 lines | 23 lines | 23 lines | 23 lines | 23 lines | 23 lines |
| Packaging | Tape & Reel | Tray | Tape & Reel | Tape & Reel | Tape & Reel | Tape & Reel |
| picoPower Technology | No | No | No | No | Yes | Yes |
主要差異化特點
- Mid-density flash in the pin-compatible ATmega family (對比ATMEGA88A-MMHR)
- Lower cost than the 32 KB variant (對比ATMEGA328P-MMHR)
- Standard AVR core without picoPower premium (對比ATMEGA168PA-MMHR)
- Tape-and-reel packaging for automated assembly (對比ATMEGA168A-MMH)
設計說明
Decouple both VCC pins (pins 4 and 6) and the AVCC pin (pin 18) with 100 nF ceramic capacitors placed within a few millimeters of the package. Add a 10 uF bulk capacitor on the board rail. For ADC accuracy, insert a 10 uH inductor or ferrite bead between VCC and AVCC to isolate digital switching noise from the analog supply, and tie AREF to AVCC through a 100 nF capacitor when using the internal reference.
The 28-VQFN (4x4 mm) package has an exposed thermal pad that must be soldered to a grounded copper area for mechanical strength and heat spreading. Use a stencil aperture of approximately 50-80% of the pad area to control solder volume and avoid bridging. Route the crystal (if used) on pins 7 and 8 with short, symmetric traces and guard them with ground; keep switching signals such as PWM outputs away from the XTAL pins to prevent clock jitter.
Do not leave the RESET pin floating; although an internal pull-up exists, add an external 10 kOhm pull-up and a 100 nF capacitor to ground for reliable operation in noisy environments. When migrating firmware between ATmega48A/88A/168A/328P variants, update the device signature and fuse bytes in the programmer, because the signature differs even though the pinout is identical. Estimated: at 5 V and 20 MHz the core draws roughly 10-12 mA, so verify the regulator can supply the MCU plus peripherals before finalizing the power budget.
合規資訊
RoHS compliance and lead-free status are stated on the Microchip ATmega168A product page and distributor listings. The device is not AEC-Q100 qualified, so it is not intended for automotive applications. REACH, halogen-free, and conflict-minerals status were not confirmed in the retrieved data.
