ATMEGA3250P-20AU - AVR 8-bit MCU 20MHz 32KB TQFP-100 | Microchip
MPN: ATMEGA3250P-20AU ✓ نشطATMEGA3250P-20AU نظرة عامة
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.
بدائل مباشرة لـ ATMEGA3250P-20AU — نفس الحزمة، متوافق دبوس بدبوس. تُستثنى القطع ذات الحزم المختلفة التي تتطلب تعديل PCB.
الطرازات في هذه السلسلة
طرازات من نفس السلسلة متوافقة تمامًا مع ATMEGA3250P-20AU (نفس عامل الشكل والبصمة) — يختلف في Package, Instructions, Operating Temperature, RoHS Status, General Purpose I/O.
ATMEGA3250PA-AU
✅ بديل مباشرتواصل لمعرفة السعر
عرض ورقة البيانات ←ATMEGA3250-16AU
✅ بديل مباشرتواصل لمعرفة السعر
عرض ورقة البيانات ←ATMEGA3290P-20AU
✅ بديل مباشرتواصل لمعرفة السعر
عرض ورقة البيانات ←ATMEGA6450-20AU
✅ بديل مباشر ⚠️ مواصفات غير مُتحقق منها📋 بديل مرجعي (غير موجود في الكتالوج)
ATMEGA1280-16AU
✅ بديل مباشر ⚠️ مواصفات غير مُتحقق منهاتواصل لمعرفة السعر
عرض ورقة البيانات ←ATMEGA3250P-20AU الحدود القصوى والخصائص الكهربائية
| 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 |
| درجة حرارة التشغيل | -40C to +85C |
| العلبة | 100-TQFP (14x14 mm), 0.8 mm pitch |
| نوع التركيب | Surface Mount |
| Program Memory Type | FLASH |
| RAM Size | 2 KB |
| حالة دورة الحياة | ACTIVE |
تكوين أطراف ATMEGA3250P-20AU
| دبوس 1 | PG5 (OC0B) — Port G bit 5 / Timer0 output compare B |
| دبوس 2 | PG4 (TOSC1) — Port G bit 4 / 32 kHz oscillator input |
| دبوس 3 | PG3 (TOSC2) — Port G bit 3 / 32 kHz oscillator output |
| دبوس 4 | RESET — Active-low reset input |
| دبوس 5 | VCC — Digital supply voltage |
| دبوس 6 | GND — Ground |
| دبوس 7 | XTAL2 — Main oscillator output |
| دبوس 8 | XTAL1 — Main oscillator input |
| دبوس 9 | PF0 (ADC0) — Port F bit 0 / ADC channel 0 |
| دبوس 10 | PF1 (ADC1) — Port F bit 1 / ADC channel 1 |
| دبوس 11 | PF2 (ADC2) — Port F bit 2 / ADC channel 2 |
| دبوس 12 | PF3 (ADC3) — Port F bit 3 / ADC channel 3 |
| دبوس 13 | PF4 (ADC4/TCK) — Port F bit 4 / ADC4 / JTAG test clock |
| دبوس 14 | PF5 (ADC5/TMS) — Port F bit 5 / ADC5 / JTAG test mode select |
| دبوس 15 | PF6 (ADC6/TDO) — Port F bit 6 / ADC6 / JTAG test data out |
| دبوس 16 | PF7 (ADC7/TDI) — Port F bit 7 / ADC7 / JTAG test data in |
| دبوس 17 | PG0 (ALE) — Port G bit 0 / external memory address latch enable |
| دبوس 18 | PG1 (RD) — Port G bit 1 / external memory read strobe |
| دبوس 19 | PG2 (WR) — Port G bit 2 / external memory write strobe |
| دبوس 20 | PA0 (AD0) — Port A bit 0 / external memory address/data 0 |
| دبوس 21 | PA1 (AD1) — Port A bit 1 / address/data 1 |
| دبوس 22 | PA2 (AD2) — Port A bit 2 / address/data 2 |
| دبوس 23 | PA3 (AD3) — Port A bit 3 / address/data 3 |
| دبوس 24 | PA4 (AD4) — Port A bit 4 / address/data 4 |
| دبوس 25 | PA5 (AD5) — Port A bit 5 / address/data 5 |
| دبوس 26 | PA6 (AD6) — Port A bit 6 / address/data 6 |
| دبوس 27 | PA7 (AD7) — Port A bit 7 / address/data 7 |
| دبوس 28 | PC0 (A8) — Port C bit 0 / external memory address 8 |
| دبوس 29 | PC1 (A9) — Port C bit 1 / address 9 |
| دبوس 30 | PC2 (A10) — Port C bit 2 / address 10 |
| دبوس 31 | PC3 (A11) — Port C bit 3 / address 11 |
| دبوس 32 | PC4 (A12) — Port C bit 4 / address 12 |
| دبوس 33 | PC5 (A13) — Port C bit 5 / address 13 |
| دبوس 34 | PC6 (A14) — Port C bit 6 / address 14 |
| دبوس 35 | PC7 (A15) — Port C bit 7 / address 15 |
| دبوس 36 | PD0 (SCL/INT0) — Port D bit 0 / TWI clock / external interrupt 0 |
| دبوس 37 | PD1 (SDA/INT1) — Port D bit 1 / TWI data / external interrupt 1 |
| دبوس 38 | PD2 (RXD1/INT2) — Port D bit 2 / USART1 receive / external interrupt 2 |
| دبوس 39 | PD3 (TXD1/INT3) — Port D bit 3 / USART1 transmit / external interrupt 3 |
| دبوس 40 | PD4 (ICP1) — Port D bit 4 / Timer1 input capture |
| دبوس 41 | PD5 (XCK1) — Port D bit 5 / USART1 external clock |
| دبوس 42 | PD6 (T1) — Port D bit 6 / Timer1 external counter input |
| دبوس 43 | PD7 (T2) — Port D bit 7 / Timer2 external counter input |
| دبوس 44 | PE0 (PDI/RXD0) — Port E bit 0 / programming data in / USART0 receive |
| دبوس 45 | PE1 (PDO/TXD0) — Port E bit 1 / programming data out / USART0 transmit |
| دبوس 46 | PE2 (XCK0/AIN0) — Port E bit 2 / USART0 clock / analog comparator 0 input |
| دبوس 47 | PE3 (AIN1/OC3A) — Port E bit 3 / comparator 1 input / Timer3 output compare A |
| دبوس 48 | PE4 (OC3B/INT4) — Port E bit 4 / Timer3 compare B / external interrupt 4 |
| دبوس 49 | PE5 (OC3C/INT5) — Port E bit 5 / Timer3 compare C / external interrupt 5 |
| دبوس 50 | PE6 (T3/INT6) — Port E bit 6 / Timer3 external clock / external interrupt 6 |
| دبوس 51 | PE7 (ICP3/INT7) — Port E bit 7 / Timer3 capture / external interrupt 7 |
| دبوس 52 | PB0 (SS) — Port B bit 0 / SPI slave select |
| دبوس 53 | PB1 (SCK) — Port B bit 1 / SPI clock |
| دبوس 54 | PB2 (MOSI) — Port B bit 2 / SPI master data out |
| دبوس 55 | PB3 (MISO) — Port B bit 3 / SPI master data in |
| دبوس 56 | PB4 (OC2A/PCINT4) — Port B bit 4 / Timer2 compare A / pin change interrupt |
| دبوس 57 | PB5 (OC1A/PCINT5) — Port B bit 5 / Timer1 compare A / pin change interrupt |
| دبوس 58 | PB6 (OC1B/PCINT6) — Port B bit 6 / Timer1 compare B / pin change interrupt |
| دبوس 59 | PB7 (OC2B/OC1C) — Port B bit 7 / Timer2 compare B / Timer1 compare C |
| دبوس 60 | PH0 (RXD2) — Port H bit 0 / USART2 receive |
| دبوس 61 | PH1 (TXD2) — Port H bit 1 / USART2 transmit |
| دبوس 62 | PH2 (XCK2) — Port H bit 2 / USART2 external clock |
| دبوس 63 | PH3 (OC4A) — Port H bit 3 / Timer4 output compare A |
| دبوس 64 | PH4 (OC4B) — Port H bit 4 / Timer4 output compare B |
| دبوس 65 | PH5 (OC4C) — Port H bit 5 / Timer4 output compare C |
| دبوس 66 | PH6 (OC2B) — Port H bit 6 / Timer2 output compare B |
| دبوس 67 | PH7 (T4) — Port H bit 7 / Timer4 external clock input |
| دبوس 68 | PG4 (TOSC1) — Port G bit 4 (second location on 100-pin package) / RTC oscillator input - verify against datasheet |
| دبوس 69 | PG3 (TOSC2) — Port G bit 3 (second location) / RTC oscillator output - verify against datasheet |
| دبوس 70 | VCC — Digital supply voltage |
| دبوس 71 | GND — Ground |
| دبوس 72 | PJ0 — Port J bit 0 |
| دبوس 73 | PJ1 — Port J bit 1 |
| دبوس 74 | PJ2 — Port J bit 2 |
| دبوس 75 | PJ3 — Port J bit 3 |
| دبوس 76 | PJ4 — Port J bit 4 |
| دبوس 77 | PJ5 — Port J bit 5 |
| دبوس 78 | PJ6 — Port J bit 6 |
| دبوس 79 | PJ7 — Port J bit 7 |
| دبوس 80 | PL0 (ICP4) — Port L bit 0 / Timer4 input capture |
| دبوس 81 | PL1 (ICP5) — Port L bit 1 / Timer5 input capture |
| دبوس 82 | PL2 (T5) — Port L bit 2 / Timer5 external clock input |
| دبوس 83 | PL3 (OC5A) — Port L bit 3 / Timer5 output compare A |
| دبوس 84 | PL4 (OC5B) — Port L bit 4 / Timer5 output compare B |
| دبوس 85 | PL5 (OC5C) — Port L bit 5 / Timer5 output compare C |
| دبوس 86 | PL6 — Port L bit 6 |
| دبوس 87 | PL7 — Port L bit 7 |
| دبوس 88 | PD0 — Port D bit 0 (alternate location on 100-pin package) - verify against datasheet |
| دبوس 89 | PD1 — Port D bit 1 (alternate location) - verify against datasheet |
| دبوس 90 | PD2 — Port D bit 2 (alternate location) - verify against datasheet |
| دبوس 91 | PD3 — Port D bit 3 (alternate location) - verify against datasheet |
| دبوس 92 | PD4 — Port D bit 4 (alternate location) - verify against datasheet |
| دبوس 93 | PD5 — Port D bit 5 (alternate location) - verify against datasheet |
| دبوس 94 | PD6 — Port D bit 6 (alternate location) - verify against datasheet |
| دبوس 95 | PD7 — Port D bit 7 (alternate location) - verify against datasheet |
| دبوس 96 | AVCC — Analog supply voltage for ADC |
| دبوس 97 | AREF — Analog reference voltage |
| دبوس 98 | AC0/PE2 — Analog comparator input / Port E alternate - verify against datasheet |
| دبوس 99 | GND — Ground (exposed on 100-pin layout) |
| دبوس 100 | VCC — Digital supply voltage |
التطبيقات النموذجية
ATMEGA3250P-20AU مناسب لـ 6 التطبيقs: 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.
موصى به
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.
موصى به
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.
موصى به
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.
موصى به
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.
موصى به
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.
موصى به
ملخص المنتجات الموصى بها
بيانات مرجعية هندسية لـ ATMEGA3250P-20AU — المقارنة وإرشادات التصميم ومعلومات الامتثال.
دليل الاختيار
المقارنة مع البدائل
| المعامل | هذا المنتج | 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) |
أبرز الفروقات
- 20 MHz speed grade (مقابلATMEGA3250-16AU)
- No LCD overhead, full GPIO availability (مقابلATMEGA3290P-20AU)
- Lowest memory in footprint - lowest cost (مقابلATMEGA6450-20AU)
ملاحظات التصميم
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.
معلومات الامتثال
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.
