ATMEGA3250P-20AU - AVR 8-bit MCU 20MHz 32KB TQFP-100 | Microchip
MPN: ATMEGA3250P-20AU ✓ פעילATMEGA3250P-20AU סקירה
A microcontroller unit (MCU) is a single integrated circuit that combines a processor core, memory, and programmable input/output peripherals, sitting at the top of the embedded control hierarchy from simple logic ICs up to full system-on-chip solutions. The AVR family popularized single-cycle RISC execution, and this ATmega device executes 131 powerful instructions, most in a single clock cycle, achieving up to 20 MIPS throughput at 20 MHz.
Key features include 69 general-purpose I/O lines with internal pull-ups, a JTAG interface for boundary-scan, on-chip debugging and programming, three flexible timer/counters with compare modes, an 8-channel 10-bit ADC, and a programmable serial USART. The picoPower technology delivers low active and sleep-mode consumption, with six software-selectable power-saving modes including idle, power-save, power-down, standby, ADC noise reduction, and extended standby.
Architecturally, the device uses a Harvard structure with separate program and data buses, 32 general-purpose working registers directly connected to the ALU, and read-while-write flash for in-system self-programming. Endurance is rated at 10,000 flash and 100,000 EEPROM write/erase cycles with 20-year data retention at 85C.
Typical applications include industrial automation controllers, building and HVAC control panels, metering systems, and consumer appliances where a 5V industrial noise margin and abundant I/O are required.
For design, ensure the supply is decoupled with 100 nF ceramics at each VCC/GND pair and drive AVCC properly even when the ADC is unused. Pricing on this page reflects distributor data as of 2026-09-17; this page adds drop-in alternatives, pinout guidance, and design notes not consolidated in the manufacturer datasheet.
חלופות תחליף ישיר עבור ATMEGA3250P-20AU — אותו מארז, תואם פין-לפין. חלקים במארז שונה הדורשים עיבוד מחדש של ה-PCB אינם נכללים.
וריאנטים בסדרה זו
דגמים מאותה סדרה התואמים Drop-in עם ATMEGA3250P-20AU (אותו גורם צורה וטביעת רגל) — שונים ב Package, Instructions, Operating Temperature, RoHS Status, General Purpose I/O.
ATMEGA3250PA-AU
✅ Drop-Inצור קשר לקבלת מחיר
הצג גיליון נתונים ←ATMEGA3250-16AU
✅ Drop-Inצור קשר לקבלת מחיר
הצג גיליון נתונים ←ATMEGA3290P-20AU
✅ Drop-Inצור קשר לקבלת מחיר
הצג גיליון נתונים ←ATMEGA6450-20AU
✅ Drop-In ⚠️ מפרטים לא מאומתים📋 חלופה להתייחסות (לא בקטלוג)
ATMEGA1280-16AU
✅ Drop-In ⚠️ מפרטים לא מאומתיםצור קשר לקבלת מחיר
הצג גיליון נתונים ←ATMEGA3250P-20AU דירוגים מרביים ומאפיינים חשמליים
| Core Processor | AVR |
| Core Size | 8-Bit |
| Speed | 20 MHz |
| Flash Memory Size | 32 KB (16K x 16) |
| SRAM Size | 2 KB |
| EEPROM Size | 1 KB |
| Supply Voltage Range | 4.5 V to 5.5 V |
| Number of I/O | 69 |
| Peripherals | Brown-out Detect/Reset, POR, PWM, WDT |
| Connectivity | SPI, UART/USART, JTAG |
| ADC Resolution | 10-bit |
| טמפרטורת פעולה | -40C to +85C |
| מארז | 100-TQFP (14x14 mm), 0.8 mm pitch |
| סוג הרכבה | Surface Mount |
| Program Memory Type | FLASH |
| RAM Size | 2 KB |
| סטטוס מחזור חיים | ACTIVE |
תצורת פינים של ATMEGA3250P-20AU
| פין 1 | PG5 (OC0B) — Port G bit 5 / Timer0 output compare B |
| פין 2 | PG4 (TOSC1) — Port G bit 4 / 32 kHz oscillator input |
| פין 3 | PG3 (TOSC2) — Port G bit 3 / 32 kHz oscillator output |
| פין 4 | RESET — Active-low reset input |
| פין 5 | VCC — Digital supply voltage |
| פין 6 | GND — Ground |
| פין 7 | XTAL2 — Main oscillator output |
| פין 8 | XTAL1 — Main oscillator input |
| פין 9 | PF0 (ADC0) — Port F bit 0 / ADC channel 0 |
| פין 10 | PF1 (ADC1) — Port F bit 1 / ADC channel 1 |
| פין 11 | PF2 (ADC2) — Port F bit 2 / ADC channel 2 |
| פין 12 | PF3 (ADC3) — Port F bit 3 / ADC channel 3 |
| פין 13 | PF4 (ADC4/TCK) — Port F bit 4 / ADC4 / JTAG test clock |
| פין 14 | PF5 (ADC5/TMS) — Port F bit 5 / ADC5 / JTAG test mode select |
| פין 15 | PF6 (ADC6/TDO) — Port F bit 6 / ADC6 / JTAG test data out |
| פין 16 | PF7 (ADC7/TDI) — Port F bit 7 / ADC7 / JTAG test data in |
| פין 17 | PG0 (ALE) — Port G bit 0 / external memory address latch enable |
| פין 18 | PG1 (RD) — Port G bit 1 / external memory read strobe |
| פין 19 | PG2 (WR) — Port G bit 2 / external memory write strobe |
| פין 20 | PA0 (AD0) — Port A bit 0 / external memory address/data 0 |
| פין 21 | PA1 (AD1) — Port A bit 1 / address/data 1 |
| פין 22 | PA2 (AD2) — Port A bit 2 / address/data 2 |
| פין 23 | PA3 (AD3) — Port A bit 3 / address/data 3 |
| פין 24 | PA4 (AD4) — Port A bit 4 / address/data 4 |
| פין 25 | PA5 (AD5) — Port A bit 5 / address/data 5 |
| פין 26 | PA6 (AD6) — Port A bit 6 / address/data 6 |
| פין 27 | PA7 (AD7) — Port A bit 7 / address/data 7 |
| פין 28 | PC0 (A8) — Port C bit 0 / external memory address 8 |
| פין 29 | PC1 (A9) — Port C bit 1 / address 9 |
| פין 30 | PC2 (A10) — Port C bit 2 / address 10 |
| פין 31 | PC3 (A11) — Port C bit 3 / address 11 |
| פין 32 | PC4 (A12) — Port C bit 4 / address 12 |
| פין 33 | PC5 (A13) — Port C bit 5 / address 13 |
| פין 34 | PC6 (A14) — Port C bit 6 / address 14 |
| פין 35 | PC7 (A15) — Port C bit 7 / address 15 |
| פין 36 | PD0 (SCL/INT0) — Port D bit 0 / TWI clock / external interrupt 0 |
| פין 37 | PD1 (SDA/INT1) — Port D bit 1 / TWI data / external interrupt 1 |
| פין 38 | PD2 (RXD1/INT2) — Port D bit 2 / USART1 receive / external interrupt 2 |
| פין 39 | PD3 (TXD1/INT3) — Port D bit 3 / USART1 transmit / external interrupt 3 |
| פין 40 | PD4 (ICP1) — Port D bit 4 / Timer1 input capture |
| פין 41 | PD5 (XCK1) — Port D bit 5 / USART1 external clock |
| פין 42 | PD6 (T1) — Port D bit 6 / Timer1 external counter input |
| פין 43 | PD7 (T2) — Port D bit 7 / Timer2 external counter input |
| פין 44 | PE0 (PDI/RXD0) — Port E bit 0 / programming data in / USART0 receive |
| פין 45 | PE1 (PDO/TXD0) — Port E bit 1 / programming data out / USART0 transmit |
| פין 46 | PE2 (XCK0/AIN0) — Port E bit 2 / USART0 clock / analog comparator 0 input |
| פין 47 | PE3 (AIN1/OC3A) — Port E bit 3 / comparator 1 input / Timer3 output compare A |
| פין 48 | PE4 (OC3B/INT4) — Port E bit 4 / Timer3 compare B / external interrupt 4 |
| פין 49 | PE5 (OC3C/INT5) — Port E bit 5 / Timer3 compare C / external interrupt 5 |
| פין 50 | PE6 (T3/INT6) — Port E bit 6 / Timer3 external clock / external interrupt 6 |
| פין 51 | PE7 (ICP3/INT7) — Port E bit 7 / Timer3 capture / external interrupt 7 |
| פין 52 | PB0 (SS) — Port B bit 0 / SPI slave select |
| פין 53 | PB1 (SCK) — Port B bit 1 / SPI clock |
| פין 54 | PB2 (MOSI) — Port B bit 2 / SPI master data out |
| פין 55 | PB3 (MISO) — Port B bit 3 / SPI master data in |
| פין 56 | PB4 (OC2A/PCINT4) — Port B bit 4 / Timer2 compare A / pin change interrupt |
| פין 57 | PB5 (OC1A/PCINT5) — Port B bit 5 / Timer1 compare A / pin change interrupt |
| פין 58 | PB6 (OC1B/PCINT6) — Port B bit 6 / Timer1 compare B / pin change interrupt |
| פין 59 | PB7 (OC2B/OC1C) — Port B bit 7 / Timer2 compare B / Timer1 compare C |
| פין 60 | PH0 (RXD2) — Port H bit 0 / USART2 receive |
| פין 61 | PH1 (TXD2) — Port H bit 1 / USART2 transmit |
| פין 62 | PH2 (XCK2) — Port H bit 2 / USART2 external clock |
| פין 63 | PH3 (OC4A) — Port H bit 3 / Timer4 output compare A |
| פין 64 | PH4 (OC4B) — Port H bit 4 / Timer4 output compare B |
| פין 65 | PH5 (OC4C) — Port H bit 5 / Timer4 output compare C |
| פין 66 | PH6 (OC2B) — Port H bit 6 / Timer2 output compare B |
| פין 67 | PH7 (T4) — Port H bit 7 / Timer4 external clock input |
| פין 68 | PG4 (TOSC1) — Port G bit 4 (second location on 100-pin package) / RTC oscillator input - verify against datasheet |
| פין 69 | PG3 (TOSC2) — Port G bit 3 (second location) / RTC oscillator output - verify against datasheet |
| פין 70 | VCC — Digital supply voltage |
| פין 71 | GND — Ground |
| פין 72 | PJ0 — Port J bit 0 |
| פין 73 | PJ1 — Port J bit 1 |
| פין 74 | PJ2 — Port J bit 2 |
| פין 75 | PJ3 — Port J bit 3 |
| פין 76 | PJ4 — Port J bit 4 |
| פין 77 | PJ5 — Port J bit 5 |
| פין 78 | PJ6 — Port J bit 6 |
| פין 79 | PJ7 — Port J bit 7 |
| פין 80 | PL0 (ICP4) — Port L bit 0 / Timer4 input capture |
| פין 81 | PL1 (ICP5) — Port L bit 1 / Timer5 input capture |
| פין 82 | PL2 (T5) — Port L bit 2 / Timer5 external clock input |
| פין 83 | PL3 (OC5A) — Port L bit 3 / Timer5 output compare A |
| פין 84 | PL4 (OC5B) — Port L bit 4 / Timer5 output compare B |
| פין 85 | PL5 (OC5C) — Port L bit 5 / Timer5 output compare C |
| פין 86 | PL6 — Port L bit 6 |
| פין 87 | PL7 — Port L bit 7 |
| פין 88 | PD0 — Port D bit 0 (alternate location on 100-pin package) - verify against datasheet |
| פין 89 | PD1 — Port D bit 1 (alternate location) - verify against datasheet |
| פין 90 | PD2 — Port D bit 2 (alternate location) - verify against datasheet |
| פין 91 | PD3 — Port D bit 3 (alternate location) - verify against datasheet |
| פין 92 | PD4 — Port D bit 4 (alternate location) - verify against datasheet |
| פין 93 | PD5 — Port D bit 5 (alternate location) - verify against datasheet |
| פין 94 | PD6 — Port D bit 6 (alternate location) - verify against datasheet |
| פין 95 | PD7 — Port D bit 7 (alternate location) - verify against datasheet |
| פין 96 | AVCC — Analog supply voltage for ADC |
| פין 97 | AREF — Analog reference voltage |
| פין 98 | AC0/PE2 — Analog comparator input / Port E alternate - verify against datasheet |
| פין 99 | GND — Ground (exposed on 100-pin layout) |
| פין 100 | VCC — Digital supply voltage |
יישומים טיפוסיים
ATMEGA3250P-20AU מתאים עבור 6 יישוםs: Industrial Automation Controllers, Building and HVAC Control Panels, Utility Metering and Data Loggers, Consumer Appliance Control, Security and Access Control Systems, Test and Measurement Instrumentation.
Industrial Automation Controllers
The ATMEGA3250P-20AU fits industrial automation controller boards because its 69 GPIO lines drive relay banks, contactors, stack lights, and HMI keypads directly, while the -40C to +85C industrial temperature rating and 4.5V-5.5V supply tolerate noisy 5V logic environments. Its 20 MHz AVR core executes 131 mostly single-cycle instructions, giving deterministic timing for PLC-style scan loops, and the watchdog plus brown-out reset recover reliably from power dips common on factory floors. Typically placed as the main control IC with a MAX232-class transceiver for RS-485/RS-232 fieldbus links; the JTAG port enables in-circuit debugging and boundary-scan manufacturing test. The trade-off is 32 KB flash, so complex protocol stacks require careful code optimization.
מומלץ
Building and HVAC Control Panels
In building automation and HVAC control panels, the ATMEGA3250P-20AU supplies the abundant I/O (69 lines) needed for zone valve outputs, fan speed relays, damper actuators, and multi-button keypads in one low-cost 5V IC. The 8-channel 10-bit ADC digitizes NTC thermistors and 0-10V sensor inputs (via dividers) with ratiometric accuracy, while three timer/counters generate PWM for triac or SSR-based heater and fan control. PicoPower sleep modes let a panel stay responsive on interrupt wake-ups while minimizing standby draw. Designers pair it with a real-time clock such as the DS1307 over I2C-bit-banged SPI/GPIO for scheduling; the main consideration is flash budget for communication stacks and display drivers.
מומלץ
Utility Metering and Data Loggers
Energy, water, and gas metering electronics benefit from the ATMEGA3250P-20AU's combination of a 10-bit ADC for current-transformer or shunt sensing, 1 KB EEPROM for calibration constants and billing registers, and six power-saving modes for battery-backed operation. The 32 KB flash accommodates measurement algorithms plus pulse-counting and communication firmware, and EEPROM endurance of 100,000 write cycles supports frequent accumulation logging. Its 5V rail matches optically isolated pulse outputs commonly found in meters. The USART streams data to GSM/RS-485 modems for AMR (automatic meter reading). Designers should reserve EEPROM wear-leveling in firmware and use the ADC noise reduction sleep mode ahead of each conversion for best resolution.
מומלץ
Consumer Appliance Control
Washing machines, dishwashers, ovens, and other white-goods appliances use the ATMEGA3250P-20AU as a main board controller where its wide 69-I/O array handles touch keys, LED segments, motor relays, door locks, and buzzer outputs without port expanders. Operating directly on the appliance's 5V derived rail with brown-out protection and watchdog supervision, it meets the reliability expectations of mains-powered household equipment, and the -40C to +85C range covers unheated garage installations. Timer PWM channels control universal motor triacs and brushless driver stages, while the ADC reads NTC temperature probes. Cost pressure makes the roughly $2.49 single-unit price (as of 2026-09-17) attractive versus 32-bit MCUs for this class of product.
מומלץ
Security and Access Control Systems
Access control panels, alarm hubs, and door controllers leverage the ATMEGA3250P-20AU's JTAG-based boundary scan for production test, its 69 GPIO for keypad matrix, reader interfaces, relay outputs, and zone loops, and its EEPROM for credential storage. The 20 MHz speed grade provides headroom for Wiegand or clock-and-data reader decoding in interrupt service routines with precise timing, and the 10-bit ADC monitors tamper switches and backup-battery voltage. Firmware can implement rolling-code and encrypted challenge-response within the 32 KB flash using lightweight AVR cryptography libraries. Design the PCB with JTAG header provision for on-chip debugging, and configure the brown-out detector to protect credential EEPROM writes during mains failures.
מומלץ
Test and Measurement Instrumentation
Bench instruments, panel meters, and custom test fixtures use the ATMEGA3250P-20AU where a 5V industrial MCU with rich I/O simplifies front-panel keypads, LED/LCD drivers, relay mux control, and IEEE-style trigger handshakes. The 10-bit ADC plus ADC noise reduction mode supports basic measurement channels, while timer capture inputs measure frequency and pulse width with timer resolution down to 50 ns at 20 MHz. The JTAG on-chip debug interface shortens bring-up during instrument firmware development, and boundary scan verifies assembled boards without a bed-of-nails fixture. Its deterministic single-cycle RISC core makes timing-critical stimulus generation predictable; reserve SRAM carefully since only 2 KB is available for buffers.
מומלץ
סיכום מוצרים מומלצים
נתוני עזר הנדסיים עבור ATMEGA3250P-20AU — השוואה, הנחיות תכנון ומידע על תאימות.
מדריך בחירה
השוואה עם חלופות
| פרמטר | מוצר זה | ATMEGA3250PA-AU | ATMEGA3250-16AU | ATMEGA3290P-20AU | ATMEGA6450-20AU | ATMEGA1280-16AU |
|---|---|---|---|---|---|---|
| Package | 100-TQFP (14x14 mm) | 100-TQFP (14x14 mm) - same | 100-TQFP (14x14 mm) - same | 100-TQFP (14x14 mm) - same | 100-TQFP (14x14 mm) - same | 100-TQFP (14x14 mm) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 32 KB | 32 KB | 32 KB | 32 KB | 64 KB | 128 KB |
| SRAM | 2 KB | 2 KB | 2 KB | 2 KB | 4 KB | 8 KB |
| Maximum Clock Speed | 20 MHz | 20 MHz | 16 MHz | 20 MHz | 20 MHz | 16 MHz |
| Supply Voltage | 4.5 V to 5.5 V | 1.8 V to 5.5 V (derated) | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V |
| General Purpose I/O | 69 | 69 | 69 | 69 (shared with LCD) | 69 (shared with LCD) | 86 |
| On-chip LCD Controller | No | No | No | Yes | Yes | No |
| PicoPower Technology | Yes (P variant) | Yes (enhanced PA) | No (base grade) | Yes (P variant) | No (base grade) | No (base grade) |
מבדילים עיקריים
- 20 MHz speed grade (לעומתATMEGA3250-16AU)
- No LCD overhead, full GPIO availability (לעומתATMEGA3290P-20AU)
- Lowest memory in footprint - lowest cost (לעומתATMEGA6450-20AU)
הערות תכנון
Decouple every VCC/GND pair with a 100 nF X7R ceramic placed within 3 mm of the pin pair, plus one 4.7 uF to 10 uF bulk capacitor near the TQFP-100 package. Connect AVCC to VCC through a low-pass filter (10 ohm resistor plus 100 nF) even if the ADC is unused - the datasheet requires AVCC to be tied to the supply for correct digital operation. Enable the brown-out detector at approximately 4.0V (BODLEVEL fuse) on 5V systems so EEPROM writes are protected during supply sag.
The 100-pin TQFP with 0.8 mm pitch requires careful escape routing; place the JTAG (TCK/TMS/TDO/TDI on port F) header near the chip edge for debug access. Keep the XTAL1/XTAL2 crystal loop compact with guard ground, and route the analog port F traces away from switching relay or motor drive lines on port L. Use a solid ground plane on layer 2 and stitch vias around the crystal and ADC reference (AREF) area to limit ground bounce at 20 MHz operation.
The -20AU is a 5V-only part: do not substitute a 3.3V-supplied equivalent without also derating the clock. When migrating firmware from non-P ATmega parts, recheck fuse defaults (clock source, JTAGEN, BODLEVEL) because picoPower variants may ship with different factory fuses, causing a board that appears dead. Also remember RESET doubles as a high-voltage programming pin; never load it with more than a weak pull-up if you may need parallel HV recovery programming.
מידע על תאימות
AU suffix designates RoHS-compliant, lead-free matte-tin TQFP package per Microchip ordering code convention. REACH and halogen-free status not stated in retrieved data.
