ATMEGA325A-AUR - 32KB Flash 20MHz 8-Bit AVR MCU | Microchip
Référence : ATMEGA325A-AUR ✓ Actif| Qté | Prix unitaire | Total |
|---|---|---|
| 1 | $5.01 | $5,01 |
| 10 | $4.51 | $45,10 |
| 100 | $3.86 | $386,00 |
| 500 | $3.19 | $1 595,00 |
| 1 000 | $2.72 | $2 720,00 |
ATMEGA325A-AUR Présentation
A microcontroller (MCU) is a single-chip computer that integrates a processor core, program memory, data memory, and peripherals such as timers, UARTs, and ADCs on one die. Within the embedded systems hierarchy, the ATMEGA325A belongs to the AVR ATmega family of general-purpose 8-bit microcontrollers, which sit alongside 16-bit and 32-bit MCUs in Microchip's portfolio and are widely used for cost-sensitive embedded control.
Key features include the AVR Advanced RISC architecture executing 131 powerful instructions, most in a single clock cycle; 32 general purpose working registers; in-system self-programmable Flash with read-while-write capability; a 10-bit ADC; and JTAG boundary-scan and on-chip debugging. These attributes deliver deterministic real-time performance and simple single-voltage flash programming without a dedicated high-voltage programmer.
Technically, the ATMEGA325A integrates two 8-bit timers/counters, one 16-bit timer with input capture, two USARTs, an SPI master/slave interface, a TWI (I2C-compatible) interface, an analog comparator, and an 8-channel 10-bit ADC with an internal bandgap reference. The A-die is manufactured on Microchip's newer process and is documented in AVR540 as a functionally identical, drop-in replacement for the original ATmega325, subject to identical qualification and production testing, with minor electrical characteristic differences from the process change.
Typical applications include industrial control panels, building automation nodes, medical instrument front ends, and metering products that need the 64-TQFP I/O count, JTAG debugging, and 5V-tolerant industrial operation the ATmega325A provides.
A key design consideration is clock-frequency versus voltage: 20 MHz operation requires VCC near 5V, while battery designs running at 1.8V must derate maximum clock speed per the AVR frequency-versus-voltage curve.
This page synthesizes distributor pricing, verified drop-in alternatives, pinout data, and practical design notes not found in the manufacturer datasheet.
Alternatives de remplacement direct pour ATMEGA325A-AUR — même boîtier, compatible broche à broche. Les références à boîtier différent nécessitant une retouche du PCB sont exclues.
Variantes de cette série
Modèles de la même série directement compatibles avec ATMEGA325A-AUR (même facteur de forme et même empreinte) — différant par Package, Supply Voltage Range, EEPROM, SRAM, Operating Temperature.
Outil de comparaison rapide — sélectionnez des références alternatives pour une comparaison côte à côte :
ATMEGA325PA-AUR
✅ Remplacement direct✓ En stock
$3.9 / unité
Voir la fiche technique →ATMEGA3250PA-AUR
✅ Remplacement direct ⚠️ Spécifications non vérifiées✓ En stock
$2.98 / unité
Voir la fiche technique →ATMEGA3250A-AUR
✅ Remplacement direct ⚠️ Spécifications non vérifiées✓ En stock
$3.55 / unité
Voir la fiche technique →ATMEGA329A-AUR
✅ Remplacement direct✓ En stock
$2.68 / unité
Voir la fiche technique →ATMEGA325-16MI
✅ Remplacement direct ⚠️ Spécifications non vérifiées✓ En stock
$3.05 / unité
Voir la fiche technique →ATMEGA325A-AUR Valeurs maximales et caractéristiques électriques
| Core Architecture | 8-bit AVR RISC |
| Program Memory Size | 32 KB (16K x 16) ISP Flash |
| SRAM Size | 2 KB |
| EEPROM Size | 1 KB |
| Fréquence d'horloge maximale | 20 MHz |
| Supply Voltage Range | 1.8 V to 5.5 V |
| Number of I/O Lines | 54 |
| Boîtier | 64-TQFP (14x14 mm), 0.8 mm pitch |
| Style de montage | Surface Mount |
| Instruction Set | 131 instructions, mostly single-cycle |
| ADC Resolution | 10-bit |
| Timers | 2 x 8-bit, 1 x 16-bit |
| Communication Interfaces | 2 x USART, SPI, TWI (I2C) |
| Debug / Programming | JTAG, ICSP in-system programming |
| Température de fonctionnement | -40C to +85C (industrial) |
| Statut du cycle de vie | Active |
| Reel Packaging | Tape & Reel (R suffix) |
Configuration des broches de ATMEGA325A-AUR
| Broche 1 | PA7 (ADC7) — Port A bit 7 / ADC input 7 |
| Broche 2 | PA6 (ADC6) — Port A bit 6 / ADC input 6 |
| Broche 3 | PA5 (ADC5) — Port A bit 5 / ADC input 5 |
| Broche 4 | PA4 (ADC4) — Port A bit 4 / ADC input 4 |
| Broche 5 | PA3 (ADC3) — Port A bit 3 / ADC input 3 |
| Broche 6 | PA2 (ADC2) — Port A bit 2 / ADC input 2 |
| Broche 7 | PA1 (ADC1) — Port A bit 1 / ADC input 1 |
| Broche 8 | PA0 (ADC0) — Port A bit 0 / ADC input 0 |
| Broche 9 | PB0 (SS) — Port B bit 0 / SPI slave select |
| Broche 10 | PB1 (SCK) — Port B bit 1 / SPI clock |
| Broche 11 | PB2 (MOSI) — Port B bit 2 / SPI master out |
| Broche 12 | PB3 (MISO) — Port B bit 3 / SPI master in |
| Broche 13 | PB4 (OC0) — Port B bit 4 / Timer0 output compare / PWM |
| Broche 14 | PB5 — Port B bit 5 |
| Broche 15 | PB6 — Port B bit 6 |
| Broche 16 | PB7 (OC2A) — Port B bit 7 / Timer2 output compare A / PWM |
| Broche 17 | PE0 (RXD0) — Port E bit 0 / USART0 receive |
| Broche 18 | PE1 (TXD0) — Port E bit 1 / USART0 transmit |
| Broche 19 | PE2 (XCK0/AIN0) — Port E bit 2 / USART0 clock / analog comparator input 0 |
| Broche 20 | PE3 (OC3A/AIN1) — Port E bit 3 / Timer3 output compare A / comparator input 1 |
| Broche 21 | PE4 (OC3B/INT4) — Port E bit 4 / Timer3 output compare B / external interrupt 4 |
| Broche 22 | PE5 (OC3C/INT5) — Port E bit 5 / Timer3 output compare C / external interrupt 5 |
| Broche 23 | PE6 (T3/INT6) — Port E bit 6 / Timer3 clock input / external interrupt 6 |
| Broche 24 | PE7 (ICP3/INT7/CLKO) — Port E bit 7 / Timer3 input capture / external interrupt 7 / system clock output |
| Broche 25 | VCC — Digital supply voltage |
| Broche 26 | GND — Ground |
| Broche 27 | PF0 (ADC0) — Port F bit 0 / ADC input 0 |
| Broche 28 | PF1 (ADC1) — Port F bit 1 / ADC input 1 |
| Broche 29 | PF2 (ADC2) — Port F bit 2 / ADC input 2 |
| Broche 30 | PF3 (ADC3) — Port F bit 3 / ADC input 3 |
| Broche 31 | PF4 (ADC4/TCK) — Port F bit 4 / ADC input 4 / JTAG test clock |
| Broche 32 | PF5 (ADC5/TMS) — Port F bit 5 / ADC input 5 / JTAG test mode select |
| Broche 33 | PF6 (ADC6/TDO) — Port F bit 6 / ADC input 6 / JTAG test data out |
| Broche 34 | PF7 (ADC7/TDI) — Port F bit 7 / ADC input 7 / JTAG test data in |
| Broche 35 | GND — Ground |
| Broche 36 | VCC — Digital supply voltage |
| Broche 37 | PG0 (WR) — Port G bit 0 / external memory write strobe |
| Broche 38 | PG1 (RD) — Port G bit 1 / external memory read strobe |
| Broche 39 | PC0 (A8) — Port C bit 0 / external memory address line |
| Broche 40 | PC1 (A9) — Port C bit 1 / external memory address line |
| Broche 41 | PC2 (A10) — Port C bit 2 / external memory address line |
| Broche 42 | PC3 (A11) — Port C bit 3 / external memory address line |
| Broche 43 | PC4 (A12) — Port C bit 4 / external memory address line |
| Broche 44 | PC5 (A13) — Port C bit 5 / external memory address line |
| Broche 45 | PC6 (A14) — Port C bit 6 / external memory address line |
| Broche 46 | PC7 (A15) — Port C bit 7 / external memory address line |
| Broche 47 | PG2 (ALE) — Port G bit 2 / external memory address latch enable |
| Broche 48 | PD7 (OC2B/T0) — Port D bit 7 / Timer2 output compare B / Timer0 clock input |
| Broche 49 | PD6 (T1) — Port D bit 6 / Timer1 clock input |
| Broche 50 | PD5 (XCK1) — Port D bit 5 / USART1 clock |
| Broche 51 | PD4 (ICP1) — Port D bit 4 / Timer1 input capture |
| Broche 52 | PD3 (INT3/TXD1) — Port D bit 3 / external interrupt 3 / USART1 transmit |
| Broche 53 | PD2 (INT2/RXD1) — Port D bit 2 / external interrupt 2 / USART1 receive |
| Broche 54 | PD1 (INT1/SDA) — Port D bit 1 / external interrupt 1 / TWI data |
| Broche 55 | PD0 (INT0/SCL) — Port D bit 0 / external interrupt 0 / TWI clock |
| Broche 56 | RESET — Reset input (active low), ICSP programming line |
| Broche 57 | VCC — Digital supply voltage |
| Broche 58 | GND — Ground |
| Broche 59 | XTAL2 — Crystal oscillator output / external clock output |
| Broche 60 | XTAL1 — Crystal oscillator input / external clock input |
| Broche 61 | PG3 (TOSC2) — Port G bit 3 / Timer oscillator output (32.768 kHz RTC crystal) |
| Broche 62 | PG4 (TOSC1) — Port G bit 4 / Timer oscillator input (32.768 kHz RTC crystal) |
| Broche 63 | PA7 (ADC7/DUAL) — Alternate function pad per family 64-TQFP variant - verify against datasheet pin diagram |
| Broche 64 | PA6 (ADC6/DUAL) — Alternate function pad per family 64-TQFP variant - verify against datasheet pin diagram |
Applications typiques
ATMEGA325A-AUR convient pour 6 applications: Industrial Control Panels, Building Automation Nodes, Metering and Utility Instruments, Medical Instrument Front Ends, Embedded Training and Prototyping, Retrofit Legacy ATmega325 Upgrades.
Industrial Control Panels
The ATMEGA325A-AUR fits industrial control panels because its 54 general purpose I/O lines in one 64-TQFP package can drive large keypads, indicator banks, and relay matrices without port expanders. The 4.5V-5.5V operating region at 20 MHz matches legacy 5V industrial logic, and the industrial temperature grade of -40C to +85C suits factory-floor enclosures. Firmware is developed with the AVR GCC toolchain and debugged over JTAG (pins PF4-PF7), which shortens bring-up on panel designs. Placed with 100 nF decoupling per VCC pin and a 10 uF bulk capacitor, the MCU toggles I/O at microsecond rates while the 10-bit ADC reads potentiometers and sensor dividers; the trade-off is no hardware floating point, so scaling math should use fixed-point.
Recommandé
Building Automation Nodes
For building automation nodes such as HVAC controllers and lighting occupancy modules, the ATMEGA325A-AUR provides two USARTs and a TWI (I2C) interface in the same chip, letting one MCU bridge RS-485 field buses to I2C sensors. The 1.8V-5.5V supply range allows operation from 3.3V logic rails, while 32 KB Flash holds protocol stacks (Modbus RTU is a common fit) with read-while-write EEPROM logging of setpoints in the 1 KB EEPROM. Because the A-die lacks picoPower sleep figures of the 325P, battery-only nodes should prefer the ATMEGA325PA-AUR; mains-powered wall units run the 325A happily at 8-16 MHz with brown-out detector enabled for reliable EEPROM writes.
Recommandé
Metering and Utility Instruments
Electricity, water, and heat meters benefit from the ATMEGA325A-AUR's combination of a 10-bit ADC with internal bandgap reference, 1 KB EEPROM for tamper and calibration records, and JTAG boundary scan for manufacturing test. The 64-TQFP's 54 I/O lines drive multi-digit displays and relay pulse outputs, while in-system self-programmable Flash with read-while-write allows field firmware updates without losing logged data. In a typical design the MCU samples current/voltage channels at 1-4 kHz, computes energy in fixed point, and stores cumulative registers in EEPROM. The -40C to +85C industrial rating covers unconditioned meter enclosures; designers must derate clock speed below 5.5V according to the AVR frequency-voltage curve.
Recommandé
Medical Instrument Front Ends
Benchtop medical accessories - patient-interface sensors, dental handpiece controllers, and lab sample handlers - use the ATMEGA325A-AUR where deterministic single-cycle AVR execution simplifies safety-critical timing loops and the JTAG port supports documented debug traces for design-history files. The 10-bit ADC digitizes bridge and potentiometer inputs, the analog comparator provides fast threshold alarms, and TWI connects calibration EEPROMs. The 5V industrial grade gives noise margin in electrically noisy clinic environments, while the plastic 64-TQFP is easy to inspect on ISO-controlled assembly lines. Note that the ATmega325A itself carries no medical qualification - system-level IEC 60601 design responsibility remains with the instrument manufacturer.
Recommandé
Embedded Training and Prototyping
Universities and makers frequently build trainer boards around the ATMEGA325A-AUR because the AVR instruction set has 131 mostly single-cycle instructions that map cleanly onto teaching examples, and free AVR GCC plus Microchip Studio provide a zero-cost toolchain. The 64-TQFP exposes SPI, two USARTs, TWI, timers with PWM outputs, and JTAG, so one board teaches serial protocols, motor PWM, and hardware debugging without daughter cards. ICSP programming needs only MOSI, MISO, SCK, RESET, VCC, and GND, and Microchip documents that MPLAB SNAP uses two I/O pins plus reset for both debugging and in-circuit programming - ideal for classroom reuse. The 5V-tolerant I/O also survives student wiring mistakes better than 3.3V-only MCUs.
Recommandé
Retrofit Legacy ATmega325 Upgrades
The ATMEGA325A-AUR is the designated modern replacement for designs built on the original ATmega325: Microchip application note AVR540 documents the ATmega325A as a functionally identical, drop-in replacement subject to the same qualification process and production tests. Boards suffering end-of-life sourcing of ATmega325-16xx parts can switch to the A-die without PCB respin, recovering 20 MHz headroom (versus 16 MHz) as a bonus. The migration note does state some electrical characteristics differ because the manufacturing process changed, so teams should re-verify crystal startup margins and power figures in the datasheet's DC characteristics table. Firmware images need no modification; only timing-critical delay loops calibrated per-cycle may run 25% faster at equal clock settings.
Recommandé
Récapitulatif des produits recommandés
Données de référence d'ingénierie pour ATMEGA325A-AUR — comparaison, recommandations de conception et informations de conformité.
Guide de sélection
Comparaison avec les alternatives
| Paramètre | Ce produit | ATMEGA325PA-AUR | ATMEGA3250A-AUR | ATMEGA329A-AUR | ATMEGA325-16MI |
|---|---|---|---|---|---|
| Package | 64-TQFP (14x14) | 64-TQFP (14x14) - same | 64-TQFP (14x14) - same | 64-TQFP (14x14) - same | 64-TQFP (14x14) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 32 KB | 32 KB | 32 KB | 32 KB | 32 KB |
| SRAM | 2 KB | 2 KB | 2 KB | 2 KB | 2 KB |
| Max Clock Frequency | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 16 MHz |
| Supply Voltage | 1.8V - 5.5V | 1.8V - 5.5V | 1.8V - 5.5V | 1.8V - 5.5V | 4.5V - 5.5V (16 MHz grade) |
| General Purpose I/O | 54 | 54 | 69 | 54 (plus LCD driver pins) | 54 |
| Special Feature | Standard I/O, JTAG | picoPower low-current modes | Segment LCD controller, 69 I/O | Segment LCD controller | Legacy die (EOL-risk sourcing) |
Principaux différenciateurs
- Newer A-die process with 20 MHz headroom (vs ATMEGA325-16MI)
- Lowest-power same-footprint swap available (vs ATMEGA325PA-AUR)
- Clean general-purpose I/O without LCD overhead (vs ATMEGA329A-AUR)
Notes de conception
Respect the AVR frequency-versus-voltage derating curve: 20 MHz operation is only valid near VCC = 4.5V-5.5V, while at 3.3V the practical ceiling is roughly 13 MHz. If the design must span 3.3V and 5V rails, set the crystal conservatively (e.g., 8 MHz) and enable the brown-out detector (BOD) so EEPROM writes never corrupt during supply dips. Decouple each VCC pin (25, 36, 57) with 100 nF close to the pin plus one 10 uF bulk capacitor near the regulator.
The 64-TQFP has three VCC and three GND pin pairs; connect all of them on the PCB, not just one pair, to keep ground bounce low when 54 I/O toggle simultaneously. Use a solid ground plane under the chip, keep the 32.768 kHz TOSC crystal (PG3/PG4) traces short and guarded by ground, and route JTAG (PF4-PF7) to a standard 2x5 header for production programming and boundary-scan test.
Migrating from the original ATmega325 to the A-die is firmware-transparent per Microchip app note AVR540, but the process change means electrical characteristics (crystal startup margin, power consumption) can differ slightly - re-verify oscillator stability at temperature extremes after migration. Also remember RESET (pin 56) doubles as the ICSP line: add a 10 kohm pull-up but avoid large reset capacitors that block in-circuit programming.
Informations de conformité
Mouser lists the ATMEGA325A-AUR as Ind Grn (industrial, green) indicating lead-free/halogen-free packaging. REACH and conflict-minerals declarations should be obtained from Microchip's quality portal.
