ATMEGA325A-ANR - 8-bit AVR MCU 32KB 20MHz TQFP-64 | Microchip
料号： ATMEGA325A-ANR ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $4.83 | $4.83 |
| 10 | $4.6 | $46.00 |
| 100 | $4.36 | $436.00 |
| 500 | $4.14 | $2,070.00 |
| 1,000 | $3.93 | $3,930.00 |
ATMEGA325A-ANR 概述
An 8-bit microcontroller (MCU) is a single-chip computer integrating a processor core, program memory, data memory, and peripherals on one die. Within the power-management and embedded-system hierarchy, the AVR ATmega family sits in the general-purpose MCU category, competing with PIC16 and other 8-bit families while offering the AVR advanced RISC architecture with 130 mostly single-cycle instructions.
Key features include 32KB of in-system-programmable Flash with read-while-write capability, 1KB EEPROM for non-volatile data storage, 54 general-purpose I/O lines, 32 general-purpose working registers, an internal oscillator, and JTAG boundary-scan/debug support. The 20MHz maximum clock rate delivers roughly 20 MIPS of throughput, and the -40C to +105C operating range of the AN suffix grade suits industrial environments.
Technically, the ATmega325A uses the AVR enhanced RISC pipeline, where most instructions execute in a single clock cycle, and Harvard architecture separates program and data buses for parallel access. The A-suffix silicon is a manufacturing-process refresh of the original ATmega325; per Microchip application note AVR540, it is a functionally identical, drop-in replacement that passes the same qualification and production tests, though some electrical characteristics differ because of the process change.
Typical applications include industrial control panels, sensor and instrumentation front ends, building automation nodes, and consumer appliances where the 54-I/O count, 10-bit ADC-class peripherals, and 105C rating provide headroom. The 64-TQFP (14x14 mm) footprint also makes it a natural upgrade path from 40-pin ATmega designs.
When designing with this device, verify the 20MHz rating against your supply voltage and temperature corner, and follow Microchip application note AVR042 for hardware design: decouple VCC/AVCC with 100nF ceramics, route RESET with a pull-up, and respect JTAG enable fuse behavior on PCB layouts that share JTAG pins with port C.
This page synthesizes distributor pricing, verified drop-in alternatives, pinout guidance, and practical design notes not found in the manufacturer datasheet, giving engineers and buyers a single decision-ready reference for the ATMEGA325A-ANR.
直接替换替代料： ATMEGA325A-ANR ——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： ATMEGA325A-ANR （相同外形与封装尺寸） ——差异在于 Package, RoHS Status, Supply Voltage Range, Core Architecture, Maximum Clock Frequency.
快速对比工具——选择替代料号进行并排对比：
ATMEGA325PA-AUR
✅ 直接替换 ⚠️ 规格未核验✓ 有现货
$3.9 / 个
查看数据手册 →ATMEGA325PA-AU
✅ 直接替换 ⚠️ 规格未核验✓ 有现货
$4.95 / 个
查看数据手册 →ATMEGA325-16AU
✅ 直接替换 ⚠️ 规格未核验✓ 有现货
$2.4 / 个
查看数据手册 →ATMEGA325A-ANR 最大额定值与电气特性
| Core Processor | AVR |
| Core Size | 8-Bit |
| Speed | 20 MHz |
| Program Memory Size | 32KB (16K x 16) Flash |
| Program Memory Type | ISP FLASH |
| RAM Size | 2K x 8 |
| EEPROM Size | 1KB |
| Number of I/O | 54 |
| Oscillator Type | Internal |
| 工作温度 | -40C to +105C |
| 封装 / 外壳 | 64-TQFP (14x14 mm) |
| 安装类型 | Surface Mount |
| Architecture | AVR Advanced RISC, 130 instructions |
| Working Registers | 32 x 8-bit general purpose |
| Debug / Scan | JTAG |
| RoHS 状态 | Compliant (Green, per FindIC listing) |
ATMEGA325A-ANR 引脚配置
| 引脚 1 | PE0 — Port E bit 0 (RXD0, USART receive) |
| 引脚 2 | PE1 — Port E bit 1 (TXD0, USART transmit) |
| 引脚 3 | PE2 — Port E bit 2 (analog comparator input) |
| 引脚 4 | PE3 — Port E bit 3 (analog comparator input) |
| 引脚 5 | PE4 — Port E bit 4 (external interrupt INT4) |
| 引脚 6 | PE5 — Port E bit 5 (external interrupt INT5) |
| 引脚 7 | PE6 — Port E bit 6 (external interrupt INT6) |
| 引脚 8 | PE7 — Port E bit 7 (external interrupt INT7) |
| 引脚 9 | GND — Ground |
| 引脚 10 | VCC — Digital supply voltage |
| 引脚 11 | PG0 — Port G bit 0 |
| 引脚 12 | PG1 — Port G bit 1 |
| 引脚 13 | PC0 — Port C bit 0 (JTAG TCK region) |
| 引脚 14 | PC1 — Port C bit 1 |
| 引脚 15 | PC2 — Port C bit 2 |
| 引脚 16 | PC3 — Port C bit 3 |
| 引脚 17 | PC4 — Port C bit 4 (JTAG TMS) |
| 引脚 18 | PC5 — Port C bit 5 (JTAG TDO) |
| 引脚 19 | PC6 — Port C bit 6 (JTAG TDI) |
| 引脚 20 | PC7 — Port C bit 7 (JTAG RTCK region) |
| 引脚 21 | GND — Ground |
| 引脚 22 | AREF — Analog reference for ADC |
| 引脚 23 | PA0 — Port A bit 0 (ADC channel 0) |
| 引脚 24 | PA1 — Port A bit 1 (ADC channel 1) |
| 引脚 25 | PA2 — Port A bit 2 (ADC channel 2) |
| 引脚 26 | PA3 — Port A bit 3 (ADC channel 3) |
| 引脚 27 | PA4 — Port A bit 4 (ADC channel 4) |
| 引脚 28 | PA5 — Port A bit 5 (ADC channel 5) |
| 引脚 29 | PA6 — Port A bit 6 (ADC channel 6) |
| 引脚 30 | PA7 — Port A bit 7 (ADC channel 7) |
| 引脚 31 | AVCC — Analog supply voltage for port A and ADC |
| 引脚 32 | PB0 — Port B bit 0 (SPI SS) |
| 引脚 33 | PB1 — Port B bit 1 (SPI SCK) |
| 引脚 34 | PB2 — Port B bit 2 (SPI MOSI) |
| 引脚 35 | PB3 — Port B bit 3 (SPI MISO) |
| 引脚 36 | PB4 — Port B bit 4 (timer output compare) |
| 引脚 37 | PB5 — Port B bit 5 (OC1A timer output) |
| 引脚 38 | PB6 — Port B bit 6 (OC1B timer output) |
| 引脚 39 | PB7 — Port B bit 7 (OC0A/OC1C timer output) |
| 引脚 40 | PD0 — Port D bit 0 (SCL, INT0) |
| 引脚 41 | PD1 — Port D bit 1 (SDA, INT1) |
| 引脚 42 | PD2 — Port D bit 2 (RXD1, INT2) |
| 引脚 43 | PD3 — Port D bit 3 (TXD1, INT3) |
| 引脚 44 | PD4 — Port D bit 4 (ICP1 input capture) |
| 引脚 45 | PD5 — Port D bit 5 (XCK1) |
| 引脚 46 | PD6 — Port D bit 6 (T1 timer input) |
| 引脚 47 | PD7 — Port D bit 7 (OC2B timer output) |
| 引脚 48 | RESET — Reset input (active low) |
| 引脚 49 | VCC — Digital supply voltage |
| 引脚 50 | GND — Ground |
| 引脚 51 | XTAL2 — Crystal oscillator output |
| 引脚 52 | XTAL1 — Crystal oscillator input |
| 引脚 53 | PG2 — Port G bit 2 |
| 引脚 54 | PG3 — Port G bit 3 (TOSC2) |
| 引脚 55 | PG4 — Port G bit 4 (TOSC1) |
| 引脚 56 | PF0 — Port F bit 0 (ADC channel 0) |
| 引脚 57 | PF1 — Port F bit 1 (ADC channel 1) |
| 引脚 58 | PF2 — Port F bit 2 (ADC channel 2) |
| 引脚 59 | PF3 — Port F bit 3 (ADC channel 3) |
| 引脚 60 | PF4 — Port F bit 4 (ADC channel 4 / TCK) |
| 引脚 61 | PF5 — Port F bit 5 (ADC channel 5 / TMS) |
| 引脚 62 | PF6 — Port F bit 6 (ADC channel 6 / TDO) |
| 引脚 63 | PF7 — Port F bit 7 (ADC channel 7 / TDI) |
| 引脚 64 | AVCC — Analog supply voltage for port F and ADC |
典型应用
ATMEGA325A-ANR 适用于 6 应用s: Industrial Control Panels, Sensor and Instrumentation Front Ends, Building Automation Nodes, Consumer Appliance Control, Test and Measurement Equipment, Security and Access Control Systems.
Industrial Control Panels
The ATMEGA325A-ANR fits industrial control panels because its -40C to +105C operating range survives cabinet heat and cold-start conditions, while 54 general-purpose I/O lines directly drive relays, contactors, push-button matrices, and multi-digit LED displays without port expanders. The 32KB ISP Flash with read-while-write supports field firmware updates over a service interface, and the 1KB EEPROM retains configuration and calibration across power cycles. Running at 20MHz, the AVR core executes most of its 130 instructions in a single cycle, providing deterministic scan times for PLC-style polling loops. Per Microchip application note AVR042, decouple each supply pin with 100nF ceramics and protect exposed I/O with TVS devices for noise immunity in electrically harsh factory environments.
推荐
Sensor and Instrumentation Front Ends
Measurement instruments benefit from the ATMEGA325A-ANR combination of an internal oscillator (removing a crystal from many designs), on-chip analog peripherals, and 32 general-purpose working registers that keep ISR latency low during ADC sampling. The 64-TQFP package exposes ample I/O for multiplexed sensor channels, front-panel keys, and display driving simultaneously. With 2KB SRAM the device buffers averaging windows and calibration tables, while 1KB EEPROM stores zero/span coefficients that survive power loss. The AVR540-confirmed process refresh means designs validated on the original ATmega325 migrate to the A die without firmware rework. For highest-resolution analog chains, pair the MCU with an external ADC over its SPI port, using the 20MHz clock to sustain fast conversion streaming and filtering in software.
推荐
Building Automation Nodes
In building automation, the ATMEGA325A-ANR serves as a room controller or actuator node: its 54 I/O lines handle damper drivers, valve outputs, occupancy inputs, and RS-485 transceiver control via its USART on port E. The internal oscillator and wide 105C rating allow fanless enclosure mounting near actuators. The 32KB Flash stores protocol stacks and scheduling tables, and read-while-write programming enables in-field firmware updates without interrupting data logging in SRAM. Sleep modes supported by the AVR architecture reduce standby current between scheduled tasks, which matters on intermittently powered nodes. Firmware can implement Modbus RTU over the USART while port C handles JTAG-based production programming, keeping one hardware design across sensor, actuator, and controller product variants.
推荐
Consumer Appliance Control
White goods and appliances use the ATMEGA325A-ANR to drive user interfaces (keys, LEDs, buzzers), motor and heater relays, and safety interlock sensing from one 64-TQFP device. The internal oscillator saves a crystal and two PCB pads, trimming bill-of-materials cost in high-volume products, while the AVR single-cycle RISC core delivers responsive interrupt handling for zero-cross detection and encoder inputs at 20MHz. The 1KB EEPROM preserves cycle counters and user presets through power interruptions, and the 32KB Flash with read-while-write allows manufacturing-line firmware personalization. Because the A-generation die is a drop-in per Microchip AVR540, appliance makers can dual-source with the original ATmega325 during supply transitions without board respins or firmware changes.
推荐
Test and Measurement Equipment
Bench instruments and handheld testers leverage the ATMEGA325A-ANR JTAG support for boundary-scan-driven production test and on-chip debugging during development, a differentiator over many small 8-bit MCUs. The 20MHz clock supports time-critical tasks such as frequency counting on the port pins, while hardware USARTs on ports E and D implement PC connectivity and module communication simultaneously. The 54 I/O lines directly switch relay matrices and drive segmented or graphic displays, and the 2KB SRAM buffers waveform snapshots for transfer. Calibrated test parameters stored in 1KB EEPROM persist through power cycles and firmware upgrades thanks to read-while-write Flash programming. The industrial temperature grade keeps specifications stable in non-conditioned service environments where handheld equipment routinely operates.
推荐
Security and Access Control Systems
Access-control panels and alarm hubs use the ATMEGA325A-ANR's 54 I/O lines to scan keypad matrices, supervise tamper loops, and drive door-strike and siren outputs from a single controller. The 105C rating tolerates heat buildup in sealed junction boxes, and the internal oscillator keeps timing accuracy adequate for watchdog and schedule functions without an external resonator. The 32KB Flash accommodates protocol handling and event logging logic, while 1KB EEPROM retains user codes and audit counters across power failures - critical for access-control compliance. Hardware USART on port E connects to RS-485 supervision buses. Per AVR042 layout guidance, route RESET with a pull-up and add input filtering on long line-powered loops to meet ESD and surge expectations of security installations.
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推荐产品汇总
工程参考数据： ATMEGA325A-ANR ——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 | ATMEGA325PA-AUR | ATMEGA325PA-AU | ATMEGA325-16AU |
|---|---|---|---|---|
| Package | 64-TQFP (14x14 mm) | 64-TQFP - same | 64-TQFP - same | 64-TQFP - same |
| Brand | Microchip Technology (Atmel) | Microchip Technology | Microchip Technology | Microchip Technology (Atmel) |
| Max Clock Speed | 20 MHz | 20 MHz | 20 MHz | 16 MHz |
| Flash Memory | 32 KB ISP | 32 KB | 32 KB | 32 KB |
| SRAM | 2 KB | 2 KB | 2 KB | 2 KB |
| EEPROM | 1 KB | 1 KB | 1 KB | 1 KB |
| I/O Count | 54 | 54 | 54 | 54 |
| Power Generation | A (process refresh) | picoPower (lower sleep current) | picoPower (lower sleep current) | original ATmega325 |
关键差异点
- 20MHz operation on A-generation silicon （对比 ATMEGA325-16AU)
- JTAG on-chip debug and boundary scan （对比 ATMEGA324PA-AUR)
- Drop-in compatibility per manufacturer migration note （对比 ATMEGA325-16AU)
设计说明
Follow Microchip application note AVR042 for hardware design: place 100nF ceramic capacitors directly across VCC-GND, AVCC-GND, and AREF-GND pin pairs on the 64-TQFP, with a 10uF bulk capacitor near the regulator. Keep the RESET trace short with a 10k pull-up, and reserve JTAG (port C/F pins) routing on the PCB even if JTAGEN is cleared in production, since enabling JTAG in-field debugging later requires those four I/O pins to be free of conflicting loads.
Verify clock-source fuses against your design: the internal oscillator is factory default, but designs that need precise UART timing or USB-class timing should use an external crystal on XTAL1/XTAL2 (pins 52/51). Changing clock fuses incorrectly can brick the device; use a programmer with high-voltage parallel programming capability as a recovery path. Also confirm the ATmega325A supply-voltage-to-frequency derating at 105C before running 20MHz at the temperature extreme.
Long I/O harnesses on a 54-I/O part are the dominant EMI/ESD entry point. Series 33-100 ohm resistors on lines leaving the board reduce ringing, and TVS diodes protect relay and keypad lines. Because port C pins are shared with JTAG, keep high-speed or analog signals off PC4-PC7 if in-system debugging is planned. Route analog ADC inputs (port A/F) away from switching outputs and guard AREF with a dedicated quiet ground pour per AVR042 analog section recommendations.
Estimated: at 20MHz and full pin loading, AVR active current is typically in the tens of mA range (exact value per datasheet current-versus-voltage graphs) - size the 3.3V/5V regulator with 2x headroom plus relay/solenoid drive currents handled externally. When migrating from ATmega325 or to ATMEGA325P picoPower silicon, re-verify sleep-mode budget: the A-generation process has different leakage characteristics than both predecessors and picoPower successors.
合规信息
FindIC listing describes the ATmega325A family as Green (RoHS-compliant) packaging. AEC-Q100 qualification not applicable to this commercial/industrial AVR grade; no REACH or conflict-minerals statements appear in the provided data.