ATMEGA644P-20MQ - 8-bit AVR MCU 64KB 20MHz VQFN-44 | Microchip
料号： ATMEGA644P-20MQ ✗ 停产| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $6.7 | $6.70 |
| 10 | $6.03 | $60.30 |
| 100 | $5.36 | $536.00 |
| 500 | $4.02 | $2,010.00 |
| 1,000 | $2.48 | $2,480.00 |
ATMEGA644P-20MQ 概述
An 8-bit microcontroller is an integrated circuit that combines a processor core, memory, and peripherals such as UARTs, timers, and ADCs on a single chip, forming the lowest tier of the embedded-computing hierarchy (MCU -> embedded processor -> system-on-chip). AVR MCUs like the ATmega644P use an enhanced RISC Harvard architecture in which most of the 131 instructions execute in a single clock cycle, yielding throughput close to 1 MIPS per MHz.
Key features of the ATMEGA644P-20MQ include dual UARTs (2-USART digital communication peripherals), picoPower low-power technology for sleep-current-sensitive designs, an internal RC oscillator that eliminates external crystals in many designs, and 32 general-purpose I/O lines organized as four 8-bit ports (PA-PD). The P suffix denotes the two-USART variant of the ATmega644 family.
The AVR core pairs the RISC engine with peripherhals including 8/16-bit timers with PWM, a 10-bit ADC with multiplexed inputs on port A, TWI (I2C-compatible) and SPI serial interfaces, brown-out detection, and in-circuit serial programming (ICSP) via the reset line using only two device I/O pins. The exposed-pad VQFN-44 package improves thermal performance and grounding over the TQFP variant.
Typical applications include industrial automation nodes, sensor acquisition systems, motor control front-ends, and embedded controllers where 64KB of flash, dual serial ports, and 5V noise immunity are required.
Design consideration: the manufacturer has marked the ATmega644P as a mature product not recommended for new designs; new boards should target the ATmega644PA, which is a pin-compatible drop-in with lower active and sleep current.
This page synthesizes verified distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
直接替换替代料： ATMEGA644P-20MQ ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
本系列中的变体
可与以下型号直接替换的同系列型号： ATMEGA644P-20MQ （相同外形与封装尺寸） ——差异在于 SRAM, Flash Memory, EEPROM, Package, RoHS Status.
快速对比工具——选择替代料号进行并排对比：
ATMEGA644PA-MQ
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
ATMEGA1284P-MQ
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
ATMEGA324P-20MQ
✅ 直接替换 ⚠️ 规格未核验✓ 有现货
$4.15 / 个
查看数据手册 →ATMEGA164P-20MQ
✅ 直接替换✓ 有现货
$2.96 / 个
查看数据手册 →ATMEGA644P-20MQ 最大额定值与电气特性
| Core Architecture | AVR 8-bit RISC |
| CPU Speed | 20 MHz |
| Throughput | Up to 20 MIPS (1 MIPS per MHz) |
| Flash Program Memory | 64 KB (32K x 16) |
| SRAM | 4 KB (4,096 bytes) |
| EEPROM | 2 KB (2,048 bytes) |
| Operating Voltage | 5 V |
| Number of I/O | 32 |
| Digital Communication Peripherals | 2 UART |
| Oscillator Type | Internal |
| Instructions | 131 powerful instructions, most single-cycle |
| 封装 | 44-VQFN (7x7 mm) with exposed pad |
| 安装类型 | Surface Mount |
| Temperature Grade | Industrial, extended temperature |
| Packaging | Tape & Reel (TR) |
| Technology Feature | picoPower low-power, green/RoHS |
| Programming | ICSP via 2 I/O pins + reset, MPLAB SNAP compatible |
| Lifecycle | Mature; NRND - replaced by ATmega644PA |
ATMEGA644P-20MQ 44-vqfn (7x7 mm) with exposed pad 引脚配置指南
ATMEGA644P-20MQ（44-vqfn (7x7 mm) with exposed pad 封装）的引脚配置。 该数字 IC 包含 GPIO、通信接口（UART、SPI、I2C）和电源引脚。请参阅制造商数据手册以了解复用引脚功能和配置选项。对嵌入式系统设计和 PCB 布局至关重要。
暂无详细引脚数据： ATMEGA644P-20MQ.
请参阅 数据手册 以查看完整引脚配置。
典型应用
ATMEGA644P-20MQ 适用于 6 应用s: Industrial Automation Nodes, Sensor Acquisition and Data Logging, Embedded Motor Control Front-Ends, 5V Industrial Communication Converters, Hobbyist and Educational Development Boards, Building Automation and Smart Home Controllers.
Industrial Automation Nodes
The ATMEGA644P-20MQ fits industrial automation nodes because its extended industrial temperature grade, 5V noise immunity, and dual UART support robust Modbus RTU and sensor-bus links on noisy factory floors. With 64KB FLASH, 4KB SRAM, and 32 I/O lines, it can host a communication stack plus local control logic without an external memory chip. Used as the main controller of an I/O expansion node or HMI front-end, the two USARTs allow simultaneous connection of a field bus and a diagnostic/debug port; hardware PWM timers drive actuators directly. The trade-off is the lack of Ethernet/CAN - add external converters for those protocols.
推荐
Sensor Acquisition and Data Logging
For battery-powered and line-powered data loggers, the ATMEGA644P-20MQ pairs a 10-bit ADC (8 channels on port A) with picoPower sleep modes that cut standby current dramatically. The 2KB EEPROM retains calibration constants and event counters across power cycles without external NVM, while 64KB FLASH stores logging firmware plus OTA-style bootloaders over either UART. Typical use: place the MCU between the sensor array and an SD or serial memory, sampling at kHz rates; sleep between samples to extend battery life. Because it is NRND, design in the pin-identical ATMEGA644PA-MQ for the same function with lower active current.
推荐
Embedded Motor Control Front-Ends
The ATMEGA644P-20MQ serves as a motor control front-end where its hardware PWM outputs, input-capture timers, and 5V operating margin are decisive. The 16-bit timer with input capture measures encoder feedback with 62.5ns resolution at 16MHz, while multiple PWM channels drive MOSFET half-bridges or servo outputs. Four 8-bit I/O ports give 32 lines for direction relays, limit switches, and status LEDs without expansion. Typical topology: MCU PWM to gate drivers, ADC channels reading current-shunt amplifiers for overcurrent detection. Trade-off: for FOC-grade control, the 20MHz AVR is modest - choose DSP-class MCUs when phase-current loops exceed 10kHz bandwidth.
推荐
5V Industrial Communication Converters
Dual UARTs make the ATMEGA644P-20MQ a natural fit for protocol converter boxes - for example RS232-to-RS485 bridges, sensor-to-Modbus gateways, and printer-interface adapters. With two independent hardware USARTs, the device buffers and translates full-duplex traffic in both directions without bit-banging, and 4KB SRAM provides generous FIFO/ring-buffer headroom for bursty links. The SPI and TWI peripherals add I2C or SPI slave ports so one converter can serve mixed-field devices. At 20MHz it sustains multi-hundred-kbaud links comfortably; above 1Mbaud, verify buffer sizing under worst-case interrupt latency before committing.
推荐
Hobbyist and Educational Development Boards
The ATmega644P family is a mainstay of open-source dev boards (notably Sanguino-class Arduino-compatible boards) because of its 64KB FLASH headroom, Arduino IDE support via AVR cores, and simple ICSP programming through MPLAB SNAP or USBasp tools. Educational designs benefit from the 5V logic that tolerates student wiring mistakes better than 3.3V parts, 32 I/O for experiments, and the internal oscillator that lets boards run crystal-less. The exposed-pad VQFN-44 keeps layouts compact, though hand-soldering the MLF pad is harder than TQFP - prototype with the TQFP ATMEGA644P-20AU before moving to the MQ for production.
推荐
Building Automation and Smart Home Controllers
In building automation, the ATMEGA644P-20MQ acts as a zone controller driving relays, reading wall-unit ADC inputs, and speaking TWI/I2C to displays and RTC modules. The 5V supply matches legacy 12/24V sensor ecosystems through simple dividers, and picoPower sleep modes support always-on occupancy sensing with low average draw. The two UARTs simultaneously handle an RS485 backbone and a service port, while 64KB FLASH leaves room for future firmware features such as scheduling and PID loops. Since the part is NRND, new smart-home designs should adopt the pin-compatible ATMEGA644PA-MQ to secure supply and gain lower sleep current.
推荐
推荐产品汇总
工程参考数据： ATMEGA644P-20MQ ——对比、设计指导和合规信息。
选型指南
与替代料对比
| 参数 | 本产品 | ATMEGA644PA-MQ | ATMEGA1284P-MQ | ATMEGA324P-20MQ | ATMEGA164P-20MQ |
|---|---|---|---|---|---|
| Package | 44-VQFN (7x7 mm) exposed pad | 44-VQFN (7x7 mm) - same | 44-VQFN (7x7 mm) - same | 44-VQFN (7x7 mm) - same | 44-VQFN (7x7 mm) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 64 KB (32K x 16) | 64 KB | 128 KB | 32 KB | 16 KB |
| SRAM | 4 KB | 4 KB | 8 KB | 2 KB | 1 KB |
| EEPROM | 2 KB | 2 KB | 4 KB | 1 KB | 512 B |
| Max CPU Speed | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| UARTs | 2 | 2 | 2 | 2 | 1 |
| Power Efficiency | picoPower (NRND - superseded) | picoPower - lowest current (best) | picoPower | picoPower | picoPower |
| Lifecycle Status | NRND (replaced by ATmega644PA) | Active (recommended for new designs) | Active | Mature | Mature |
关键差异点
- Dual UART in the ATmega644P family （对比 ATMEGA644-20AU (non-P variant))
- Exposed-pad VQFN for better grounding （对比 ATMEGA644P-20AU (TQFP))
- Larger memory than the ATmega324 tier at lower cost than 128KB （对比 ATMEGA324P-20MQ)
设计说明
This part is officially NRND: Microchip's datasheet states it is a mature product replaced by the ATmega644PA. Do not start new PCB designs with ATMEGA644P-20MQ; specify ATMEGA644PA-MQ instead, which is pin-to-pin identical and firmware-compatible. For boards already using the 644P, qualify the PA as a second source now, before lead times force an unplanned migration.
The 44-VQFN (7x7 mm) package has an exposed center pad that must be soldered to a ground via array for reliable grounding and thermal performance - it also removes heat and anchors the die. Use 4-6 via connections to the ground plane under the pad and follow the datasheet land pattern exactly. If your assembly house cannot reliably reflow QFN packages, prototype with the pin-compatible TQFP version (ATMEGA644P-20AU) which is easier to inspect and rework.
Operating at 5V is required for the full 20MHz clock; attempting lower supply voltages derates maximum frequency. Decouple both VCC pins and AVCC with 100nF ceramics placed within a few millimeters of each pin, and keep the analog supply (AVCC) filtered via an LC network when ADC accuracy matters. Enable the brown-out detector via fuses so EEPROM writes are protected during supply dips - a corrupted EEPROM during power-down is a common field failure in AVR designs.
ICSP/ISP programming shares the SPI pins (SCK, MOSI, MISO) and reset with application circuitry. Insert series resistors (typically 1k ohm) on these nets so the programmer can drive them without fighting peripheral loads, and avoid using the reset pin as a general I/O (disable with fuses) or in-circuit debugging will be impossible. Keep the ISP header traces short and away from switching loads such as relay coils or PWM motor lines.
合规信息
Verified web data describes the part as Green/RoHS for the ATmega644P MLF device (FindIC listing: 'Ext Temp, Green, 5V'). REACH, halogen-free, and conflict-minerals status not explicitly stated in provided data.