Microchip Technology

ATMEGA644P-15AT - 8-bit AVR MCU 64KB Flash 16MHz TQFP-44 | Microchip

Teilenummer: ATMEGA644P-15AT ✗ Abgekündigt
Auf Lager Versand in 1–3 Werktagen
2.7 V to 5.5 V Vdss 44-pin TQFP (10x10 mm) Package 16 MHz (at 5V) Speed 64 KB (32K x 16) Memory
Ab $4.12 USD / Stück
MOQ: 1 |
Preis aktualisiert: 2026-10-06
Mengenpreise
Menge Stückpreis Gesamt
1 $6.42 $6,42
10 $5.78 $57,80
100 $5.15 $515,00
500 $4.61 $2.305,00
1.000 $4.12 $4.120,00
ℹ️ Alle Preise sind in USD

ATMEGA644P-15AT Übersicht

The Microchip Technology (Atmel) ATMEGA644P-15AT is an 8-bit AVR enhanced RISC microcontroller integrating 64KB of in-system programmable Flash, 4KB SRAM, and 2KB EEPROM in a 44-pin TQFP (10x10 mm) surface-mount package. It executes instructions in a single clock cycle, delivering throughputs approaching 1 MIPS per MHz at its 16MHz maximum operating frequency. The -15AT speed grade is the 16MHz @ 5V industrial variant; the same die is offered as -20AU at 20MHz.

A microcontroller (MCU) is a single-chip computer that integrates a processor core, program memory (Flash), data memory (SRAM), non-volatile storage (EEPROM), and peripherals such as timers, serial interfaces, and analog-to-digital converters. Within the AVR ATmega hierarchy, the ATmega644P sits in the mid-to-high range: ATmega48 < ATmega88 < ATmega164P < ATmega324P < ATmega644P < ATmega1284, all built on the AVR 8-bit RISC core with Atmel picoPower technology for reduced active and sleep-mode current.

Key differentiating features include 32 general-purpose I/O lines, two USARTs (the 'P' suffix denotes the dual-USART enhancement over the original ATmega644), an 8-channel 10-bit ADC with optional differential mode and programmable gain, a byte-oriented 2-wire serial interface (TWI/I2C), SPI, three flexible Timer/Counters with PWM, a Real-Time Counter, and a programmable Watchdog Timer. In-system programmable Flash with Read-While-Write capability allows firmware updates without chip removal.

Typical applications include industrial automation nodes, embedded sensor data acquisition with the 10-bit ADC, RS-232/RS-485 communication gateways using dual USARTs, hobbyist/Arduino-compatible designs (supported by the MightyCore hardware package), and AEC-Q100 grade 1 qualified automotive-adjacent systems where -40C to +85C operation is required.

When designing, observe the 10x10 mm TQFP land pattern, decouple VCC and AVCC, and verify external crystal drive levels. The two-cycle load/store architecture and Harvard memory layout are transparent to C code but influence interrupt latency. Be aware that ATMEGA644P-15AT is mature and not recommended for new designs - the ATmega644PA successor is preferred.

This page synthesizes verified distributor listings, AEC-Q100 qualification references, drop-in family alternatives (including the ATmega644PA successor), and practical design notes not consolidated in the manufacturer datasheet.

Drop-in-Alternativen für ATMEGA644P-15AT – gleiches Gehäuse, Pin-kompatibel. Bauteile mit anderem Gehäuse, die eine PCB-Überarbeitung erfordern, sind ausgeschlossen.

Varianten dieser Serie

Modelle derselben Serie, die drop-in-kompatibel sind mit ATMEGA644P-15AT (gleiche Bauform und Footprint) – abweichend in Package, ADC, Core Architecture, EEPROM, RoHS Status.

Microchip Technology
Package: TQFP-44 (10x10 mm)
ADC: 10-bit, 8-channel
Core Architecture: 8-bit AVR RISC
Vergleichen mit ATMEGA644P-15AT →
Microchip Technology
Package: 44-TQFP (10x10 mm)
ADC: 8-channel, 10-bit
Core Architecture: AVR 8-bit RISC
Vergleichen mit ATMEGA644P-15AT →
Microchip Technology
EEPROM: 512 B
Vergleichen mit ATMEGA644P-15AT →
Microchip Technology
Core Architecture: 8-bit AVR RISC
Vergleichen mit ATMEGA644P-15AT →
Microchip Technology
Package: 44-pin TQFP (10x10 mm), 0.80 mm pitch
ADC: 8-channel, 10-bit
Core Architecture: AVR 8-bit RISC
Vergleichen mit ATMEGA644P-15AT →
Microchip Technology
Package: 44-TQFP (10x10 mm)
RoHS Status: Compliant (green package)
Vergleichen mit ATMEGA644P-15AT →
Microchip Technology
ADC: 8-channel, 10-bit
Core Architecture: AVR 8-bit RISC
Vergleichen mit ATMEGA644P-15AT →
Microchip Technology
Package: 44-TQFP (10 x 10 mm)
ADC: 8-channel 10-bit
Core Architecture: 8-bit AVR RISC (Harvard)
Vergleichen mit ATMEGA644P-15AT →
Microchip Technology
Package: 44-VQFN (7x7 mm), exposed pad
ADC: 8-channel 10-bit ADC
Core Architecture: 8-bit AVR RISC
Vergleichen mit ATMEGA644P-15AT →

Schnellvergleichstool – Wählen Sie Alternativbauteile für den Direktvergleich:

ATMEGA644PA-AU

✅ Drop-In
Microchip Technology
📦 44-pin TQFP (10x10 mm)
AVR 8-bit RISC · ATmega · ATmega644P / picoPower · 20 MHz · 64 KB (32K x 16) · 4 KB · 2 KB · 1.8 V to 5.5 V

✓ Auf Lager

$4.61 / Stück

Datenblatt ansehen →

ATMEGA644PA-MU

✅ Drop-In
Microchip Technology
📦 44-pin TQFP (10x10 mm)
8-bit AVR RISC · 20 MHz · 64 KB (32K x 16) ISP Flash, read-while-write · 2 KB · 4 KB · 32 · Up to 20 MIPS at 20 MHz · 131 instructions, most single-cycle

✓ Auf Lager

$3.78 / Stück

Datenblatt ansehen →

ATMEGA644P-20AU

✅ Drop-In
Microchip Technology
📦 44-pin TQFP (10x10 mm)
AVR 8-bit RISC · 8-Bit · 20 MHz · 64 KB (32K x 16) FLASH · 4 KB SRAM · 2 KB · 4.5 V to 5.5 V (20 MHz grade) · 2

✓ Auf Lager

$3.95 / Stück

Datenblatt ansehen →

ATMEGA644PA-AUR

✅ Drop-In ⚠️ Spezifikationen ungeprüft
Microchip Technology
📦 44-pin TQFP (10x10 mm)
8-bit AVR RISC (Harvard) · 64 KB (32K x 16) with read-while-write · 4 KB · 2 KB · 20 MHz · 20 MIPS (1 MIPS per MHz) · 131 instructions, mostly single-clock cycle · On-chip 2-cycle multiplier

✓ Auf Lager

$1.78 / Stück

Datenblatt ansehen →

ATMEGA1284P-AU

✅ Drop-In
Microchip Technology
📦 44-pin TQFP (10x10 mm)
8-bit AVR RISC · 128 KB · 4 KB · 16 KB · 20 MHz · 1.8 V to 5.5 V · 32 · 32

✓ Auf Lager

$4.65 / Stück

Datenblatt ansehen →

ATMEGA324PV-10AU

✅ Drop-In
Microchip Technology
📦 44-pin TQFP (10x10 mm)
AVR 8-bit RISC · 32 KB (16K x 16) · 1 KB · 2 KB · 10 MHz · 1.8 V to 5.5 V · 32 · 32

✓ Auf Lager

$4.3 / Stück

Datenblatt ansehen →

ATMEGA164A-AU

✅ Drop-In
Microchip Technology
📦 44-pin TQFP (10x10 mm)
AVR 8-bit RISC · 16 KB (8K x 16) · 512 B · 1 KB · 20 MHz (20 MIPS) · 2.7 V to 5.5 V (4.5V-5.5V at 20MHz) · 32 · 8-channel, 10-bit

✓ Auf Lager

$2.65 / Stück

Datenblatt ansehen →

ATMEGA644P-15AT Grenzwerte & elektrische Eigenschaften

Core Architecture AVR 8-bit enhanced RISC
Program Memory (Flash) 64 KB (32K x 16)
SRAM 4 KB
EEPROM 2 KB
Maximale Taktfrequenz 16 MHz (at 5V)
Throughput Up to 1 MIPS per MHz (16 MIPS peak)
Operating Voltage (VCC) 2.7 V to 5.5 V
General-Purpose I/O Lines 32
ADC 8-channel, 10-bit, with differential mode
USART 2 (dual USART, 'P' variant)
SPI 1 master/slave
TWI (I2C) 1 byte-oriented
Timer/Counters 3 with PWM and compare modes
Watchdog Timer Yes, programmable
Gehäuse 44-pin TQFP (10x10 mm)
Montageart Surface Mount
Betriebstemperatur -40C to +85C (industrial)
AEC-Q100 Qualification Grade 1
RoHS-Status Compliant
In-System Programmable Yes (Flash, Read-While-Write)
picoPower Technology Yes

ATMEGA644P-15AT Pin-Konfiguration

Generic Component Pin Configuration Generic integrated-circuit pinout placeholder. Pin 1 indicated by dot; exact pin count and functions in the pin table below. 1 N 2 N-1 3 N-2 4 N-3 Pin Configuration See pin table below for pin functions Package-specific diagram not available
Pin 1 VCC — Digital supply voltage (5V nominal)
Pin 2 GND — Digital ground
Pin 3 AVCC — Analog supply voltage
Pin 4 AGND — Analog ground
Pin 5 AREF — ADC reference voltage
Pin 6 ADC0 — Analog input channel 0
Pin 7 ADC1 — Analog input channel 1
Pin 8 ADC2 — Analog input channel 2
Pin 9 ADC3 — Analog input channel 3
Pin 10 ADC4 — Analog input channel 4
Pin 11 ADC5 — Analog input channel 5
Pin 12 ADC6 — Analog input channel 6
Pin 13 ADC7 — Analog input channel 7
Pin 14 PC0 — Port C bit 0 (GPIO)
Pin 15 PC1 — Port C bit 1 (GPIO)
Pin 16 PC2 — Port C bit 2 (GPIO)
Pin 17 PC3 — Port C bit 3 (GPIO)
Pin 18 PC4 — Port C bit 4 (GPIO)
Pin 19 PC5 — Port C bit 5 (GPIO)
Pin 20 PC6 — Port C bit 6 (GPIO)
Pin 21 PC7 — Port C bit 7 (GPIO)
Pin 22 PA0 — Port A bit 0 (GPIO)
Pin 23 PA1 — Port A bit 1 (GPIO)
Pin 24 PA2 — Port A bit 2 (GPIO)
Pin 25 PA3 — Port A bit 3 (GPIO)
Pin 26 PA4 — Port A bit 4 (GPIO)
Pin 27 PA5 — Port A bit 5 (GPIO)
Pin 28 PA6 — Port A bit 6 (GPIO)
Pin 29 PA7 — Port A bit 7 (GPIO)
Pin 30 VCC — Digital supply voltage (second pad)
Pin 31 GND — Digital ground (second pad)
Pin 32 XTAL2 — Crystal oscillator output
Pin 33 XTAL1 — Crystal oscillator input
Pin 34 PD0 — Port D bit 0 (RXD0 / GPIO)
Pin 35 PD1 — Port D bit 1 (TXD0 / GPIO)
Pin 36 PD2 — Port D bit 2 (RXD1 / GPIO)
Pin 37 PD3 — Port D bit 3 (TXD1 / GPIO)
Pin 38 PD4 — Port D bit 4 (GPIO)
Pin 39 PD5 — Port D bit 5 (GPIO)
Pin 40 PD6 — Port D bit 6 (GPIO)
Pin 41 PD7 — Port D bit 7 (GPIO)
Pin 42 RESET — Reset input (active low)
Pin 43 PB0 — Port B bit 0 (GPIO)
Pin 44 PB1 — Port B bit 1 (GPIO)

Typische Anwendungen

ATMEGA644P-15AT ist geeignet für 6 Anwendungs: Industrial Sensor Data Acquisition, RS-232 / RS-485 Communication Gateway, Hobbyist / Arduino-Compatible Custom Boards, Automotive-Adjacent Control Nodes, Embedded Control with TWI / SPI Peripherals, PWM and Timer-Control Applications.

🏭

Industrial Sensor Data Acquisition

The ATMEGA644P-15AT is well suited for industrial sensor data acquisition nodes. Its 8-channel, 10-bit ADC with optional differential inputs and programmable gain handles bridge-style sensors (load cells, strain gauges) and 4-20 mA loops with external conditioning. The 16 MHz core delivers 16 MIPS, fast enough to oversample the ADC and apply digital filtering in firmware. The 4 KB data SRAM buffers multi-channel scans before serial upload, while 64 KB Flash stores calibration coefficients in the EEPROM (2 KB). Dual USARTs support simultaneous RS-485 sensor bus and debug console. Operating temperature -40C to +85C covers most industrial cabinets. AEC-Q100 Grade 1 qualification supports automotive-adjacent sites. Compact 10x10 mm TQFP-44 footprint fits dense PLC modules.

🌐

RS-232 / RS-485 Communication Gateway

Dual USARTs make the ATMEGA644P-15AT a natural choice for protocol-conversion gateways. One port can interface to RS-232 (e.g. legacy instruments, GPS modules) while the other drives an RS-485 bus (Modbus RTU, DMX512, proprietary industrial protocols). The 16 MHz throughput easily handles 115200 baud with DMA-style polling plus protocol parsing. 4 KB SRAM buffers incoming Modbus frames before forwarding, and 64 KB Flash stores protocol stacks and configuration. Hardware CRC and the USART error-detection flags reduce software overhead. TQFP-44 fits standard gateway enclosures, and 5V tolerance simplifies interface to industrial transceivers like MAX485 or MAX3232. Consider ATmega644PA-AU for lower quiescent current in battery-backed installations.

🔧

Hobbyist / Arduino-Compatible Custom Boards

The ATMEGA644P-15AT is widely supported by the MightyCore Arduino hardware package, which adds ATmega644/P/PA board variants to the Arduino IDE. Its 64 KB Flash hosts full sketches with bootloader, the 4 KB SRAM is generous for Arduino-style String operations, and 32 digital pins (plus analog) suit many hobby projects. The dual USARTs allow simultaneous USB-serial programming and GPS or Bluetooth modules. The 16 MHz @ 5V core matches the Arduino Uno timing, easing code porting. TQFP-44 fits hand-solderable breakout boards; users wanting QFN prefer the -MU. For new designs the ATmega644PA-AU is recommended, but existing P-based projects continue to work. The 10-bit ADC is adequate for hobby analog sensors (light, temperature, potentiometers).

🚗

Automotive-Adjacent Control Nodes

AEC-Q100 Grade 1 qualification allows the ATMEGA644P-15AT to serve in automotive-adjacent control nodes such as body controllers, HVAC sub-modules, sensor clusters, and aftermarket accessories. The 64 KB Flash stores application code plus CAN-style protocol tables; the 2 KB EEPROM records calibration and fault logs that survive key-off cycles. The 8-channel 10-bit ADC reads thermistors, potentiometers, and battery-voltage dividers. Dual USARTs can drive a LIN bus via external transceiver plus a debug port. The -40C to +85C operating range covers cabin and underhood-near-side locations. picoPower modes lower quiescent draw during key-off. For new automotive designs Microchip recommends the ATmega644PA family with equivalent or better automotive qualification and improved sleep currents.

🖥️

Embedded Control with TWI / SPI Peripherals

The ATMEGA644P-15AT combines a hardware TWI (I2C) interface and an SPI master/slave port, supporting simultaneous displays, sensors, and external memory. Typical setups use TWI for an I2C OLED or character LCD plus an RTC chip (e.g. DS3231), and SPI for an SD-card logger or high-speed ADC. The 16 MIPS throughput handles 8 MHz SPI transfers to SD cards with FAT filesystem overhead. The 32 GPIO lines can bit-bang additional peripherals when hardware ports are busy, useful for WS2812 LED chains or custom LCD interfaces. 4 KB SRAM holds the FAT directory cache and a small framebuffer. The 10x10 mm TQFP-44 layout fits handheld datalogger enclosures.

⚡

PWM and Timer-Control Applications

Three flexible 16-bit Timer/Counters with PWM and compare modes make the ATMEGA644P-15AT effective for motor-drive, lighting, and power-conversion control. Phase-correct PWM at 16 MHz / 256 resolution yields ~62 kHz carrier with 8-bit duty control, or 122 Hz at 16-bit resolution. Three timers drive multi-phase BLDC commutation, three independent LED channels, or a synchronous buck converter's switch / synchronous rectifier pair. The Programmable Watchdog Timer prevents firmware lockup in unattended installations, and the Real-Time Counter with separate oscillator handles timekeeping in sleep modes. The 32 GPIO lines dedicate the rest of the part to feedback signals (encoder, current sense, fault). Robust 5V I/O tolerates industrial transients.

Zusammenfassung der empfohlenen Produkte

ATMEGA644PA-AU Microchip Technology Verwendet in: Industrial Sensor Data Acquisition, RS-232 / RS-485 Communication Gateway, Hobbyist / Arduino-Compatible Custom Boards, Automotive-Adjacent Control Nodes, PWM and Timer-Control Applications MAX485 RS-485 transceiver for sensor bus Verwendet in: Industrial Sensor Data Acquisition, RS-232 / RS-485 Communication Gateway MCP6002 Op-amp for sensor signal conditioning Verwendet in: Industrial Sensor Data Acquisition MAX3232 RS-232 transceiver Verwendet in: RS-232 / RS-485 Communication Gateway CH340G WCH Verwendet in: Hobbyist / Arduino-Compatible Custom Boards ATMEGA328P-AUR Microchip Technology Verwendet in: Hobbyist / Arduino-Compatible Custom Boards TJA1027 LIN transceiver for body control Verwendet in: Automotive-Adjacent Control Nodes MCP2561 CAN transceiver for automotive bus Verwendet in: Automotive-Adjacent Control Nodes DS3231 I2C RTC with TCXO Verwendet in: Embedded Control with TWI / SPI Peripherals W25Q64 SPI flash for data logging Verwendet in: Embedded Control with TWI / SPI Peripherals SSD1306 I2C OLED display controller Verwendet in: Embedded Control with TWI / SPI Peripherals IR2104 Half-bridge gate driver for motor control Verwendet in: PWM and Timer-Control Applications ACS712 Allegro MicroSystems Verwendet in: PWM and Timer-Control Applications
What is the maximum clock frequency of ATMEGA644P-15AT?
The ATMEGA644P-15AT runs at 16 MHz maximum when VDD is in the 4.5 V to 5.5 V range. According to the Atmel/Microchip ATmega644P datasheet, the -15 speed grade is characterized for 16 MHz at 5 V; the same die sold as -20AU runs 20 MHz at 5 V. Throughput approaches 1 MIPS per MHz, giving 16 MIPS peak. Below 4.5 V the maximum frequency derates per the speed-grade table.
What is the difference between ATMEGA644P-15AT and ATMEGA644PA-AU?
The ATMEGA644P-15AT is the mature/not-recommended-for-new-designs predecessor rated for 16 MHz at 5 V, while the ATMEGA644PA-AU is the picoPower-successor rated 20 MHz at 5 V. Both share the AVR 8-bit core, 64 KB Flash, 4 KB SRAM, 2 KB EEPROM, and dual USARTs. The PA die has lower active and sleep-mode current per picoPower technology. Pinout is compatible across TQFP-44 packages; firmware written for the P runs unchanged on the PA.
Is ATMEGA644P-15AT still in production?
The ATMEGA644P-15AT is marked mature product and not recommended for new designs by Microchip. It is replaced by the ATmega644PA family. As of 2026-10-07, distributor listings still exist on DigiKey, Mouser and Octopart with limited inventory. Engineers planning new designs should choose the ATmega644PA-MU or ATmega644PA-AU; designers maintaining legacy hardware may still use the P variant.
Where can I download the ATMEGA644P-15AT datasheet PDF?
The official Microchip ATmega644P datasheet is hosted at https://ww1.microchip.com/downloads/en/DeviceDoc/Atmel-42744-ATmega644P_Datasheet.pdf. The document covers the entire ATmega644P and ATmega644PA family including pinout, electrical characteristics, instruction set, and peripheral reference. Third-party mirrors on alldatasheet.com and findic.us also host the PDF but the Microchip URL is the authoritative source.
How much Flash, SRAM, and EEPROM does ATMEGA644P-15AT have?
The ATMEGA644P-15AT integrates 64 KB of in-system programmable Flash organized as 32K x 16, 4 KB of SRAM for data, and 2 KB of EEPROM for non-volatile parameter storage. The Flash supports Read-While-Write, allowing one section to update while another executes. This is the largest memory configuration in the ATmega164/324/644 series; the smaller 16 KB and 32 KB parts are ATmega164P and ATmega324P respectively.
What package does ATMEGA644P-15AT use and how many pins?
The ATMEGA644P-15AT is supplied in a 44-pin TQFP (Thin Quad Flat Pack) measuring 10 mm by 10 mm with 0.8 mm pitch and surface-mount leads. The -15AT suffix encodes the 16 MHz @ 5 V speed grade and TQFP package. The same silicon is also offered in 40-pin PDIP (P variant) and 44-pin VQFN/QFN packages. Engineers migrating to the PA successor should note that ATmega644PA-AU is 44-pin TQFP and pin-compatible.
Does ATMEGA644P-15AT have two USARTs?
Yes, the ATMEGA644P-15AT features two hardware USARTs (Universal Synchronous/Asynchronous Receiver-Transmitters). The 'P' in the part number distinguishes it from the non-P ATmega644 that has only one USART. The dual USARTs allow simultaneous RS-232 and RS-485 channels, GPS module plus debug console, or wired/wireless bridging without an external UART. They share the 16-bit baud-rate generator and operate independently.
Is ATMEGA644P-15AT AEC-Q100 qualified?
The ATMEGA644P-15AT is AEC-Q100 Grade 1 qualified per Microchip qualification documentation, supporting automotive-adjacent applications from -40C to +85C with PPAP documentation. Grade 1 is the most stringent automotive stress level. Note that the P is marked mature; for new automotive designs Microchip recommends the ATmega644PA family which carries equivalent or better automotive qualification and the picoPower low-current enhancements.
Where to buy ATMEGA644P-15AT online?
Buy yes - DigiKey, Mouser and Octopart all list the ATMEGA644P-15AT in 44-pin TQFP with same-day shipping options visible on the DigiKey listing as of 2026-10-07. Authorized distributors include DigiKey (SKU 1914614), Mouser, and Microchip USA. Given the part is mature and not recommended for new designs, stock is limited and lead times for larger reels may extend 8-12 weeks; consider the ATmega644PA-MU or ATmega644PA-AU for new designs.
What is the price of ATMEGA644P-15AT?
The ATMEGA644P-15AT is priced at approximately $6.42 per unit at qty 1, dropping to roughly $4.12 per unit at qty 1000 on distributor listings as of 2026-10-07. The mature status means price is volatile: stock shortages can push qty-1 pricing above $10 while volume orders from authorized stockists remain more stable. Compare with the ATmega644PA-MU which often prices 10-20 percent lower due to active production.
What is the lead time for ATMEGA644P-15AT?
Lead time for the ATMEGA644P-15AT varies by distributor and reel size as of 2026-10-07. Authorized-franchise DigiKey and Mouser typically show same-day shipping for small quantities from local warehouse stock. Larger 1000-piece reels may be on 8-12 week factory lead time due to mature lifecycle classification. For predictable supply, design engineers are advised to qualify the ATmega644PA-MU or ATmega644PA-AU as a drop-in alternative.
ATMEGA644P-15AT vs ATMEGA644P-20AU - which is faster?
The ATMEGA644P-20AU runs at 20 MHz maximum versus 16 MHz for the ATMEGA644P-15AT, both at 5 V. Both parts share the same 64 KB Flash, 4 KB SRAM, 2 KB EEPROM, and dual USARTs. The -20AU is therefore 25 percent faster in instruction throughput. Both use the TQFP-44 package; the suffix differs only in speed grade (15 vs 20) and pin-1 orientation (AT vs AU reverses pin-1 mark). New designs should consider the ATmega644PA-AU which runs 20 MHz at lower current.
What is the best drop-in replacement for ATMEGA644P-15AT?
The best drop-in replacement for the ATMEGA644P-15AT is the ATmega644PA-MU (or ATmega644PA-AU for TQFP-44). It uses the same AVR 8-bit core, 64 KB Flash, 4 KB SRAM, 2 KB EEPROM, dual USARTs, and pin-compatible 44-pin TQFP package. The PA die is rated 20 MHz at 5 V versus 16 MHz for the P, and adds picoPower sleep modes. Existing firmware written for the P runs unchanged; the PA simply executes faster with lower quiescent current. Per Microchip product page, the PA is the recommended successor.
When should I choose ATMEGA644P-15AT over the ATmega644PA?
Choose the ATMEGA644P-15AT only for maintaining or repairing existing hardware where the PA would require firmware re-validation. For new designs, choose the ATmega644PA-AU or ATmega644PA-MU because the PA is actively produced, has lower active and sleep-mode current per picoPower technology, supports 20 MHz at 5 V versus 16 MHz for the P, and offers longer supply continuity. Both are pin-compatible in 44-pin TQFP, so layout work is identical.

Technische Referenzdaten für ATMEGA644P-15AT – Vergleich, Designhinweise und Compliance-Informationen.

Auswahlhilfe

Choose the ATMEGA644P-15AT only for maintaining or repairing legacy hardware where the PA successor would require firmware revalidation, or where existing inventory and toolchain are already qualified. For new designs, prefer the ATMEGA644PA-AU (44-pin TQFP, 20 MHz, picoPower, AEC-Q100) which is the actively produced successor. Pick the ATmega1284P-AU if your application outgrows the 64 KB Flash / 4 KB SRAM ceiling and you want to stay in the same 44-pin TQFP package. The 32 KB / 2 KB ATmega324PV-10AU fits cost-sensitive, low-voltage (1.8 V) designs where the smaller Flash is acceptable. For dual-USART, 10-bit ADC, and AVR core compatibility, no AVR alternative matches the ATmega644P family without accepting different memory or package.

Vergleich mit Alternativen

Parameter Dieses Produkt ATMEGA644PA-AU ATMEGA644PA-MU ATMEGA644P-20AU ATMEGA1284P-AU ATMEGA324PV-10AU
Brand Microchip Technology Microchip Technology Microchip Technology Microchip Technology Microchip Technology Microchip Technology
Package 44-pin TQFP (10x10 mm) 44-pin TQFP (10x10 mm) - same 44-pin TQFP (10x10 mm) - same 44-pin TQFP (10x10 mm) - same 44-pin TQFP (10x10 mm) - same 44-pin TQFP (10x10 mm) - same
Flash 64 KB 64 KB 64 KB 64 KB 128 KB 32 KB
SRAM 4 KB 4 KB 4 KB 4 KB 16 KB 2 KB
EEPROM 2 KB 2 KB 2 KB 2 KB 4 KB 1 KB
Max Clock 16 MHz 20 MHz 20 MHz 20 MHz 20 MHz 10 MHz (low-voltage)
Operating Voltage 2.7 V to 5.5 V 1.8 V to 5.5 V 1.8 V to 5.5 V 2.7 V to 5.5 V 1.8 V to 5.5 V 1.8 V to 5.5 V
Dual USART Yes Yes Yes Yes Yes Yes
picoPower Yes Yes Yes Yes Yes Yes
Lifecycle Mature (not for new designs) Active Active Mature Active Active

Wichtigste Unterscheidungsmerkmale

  • Officially designated as the mature successor's predecessor (vs. ATMEGA644PA-AU)
  • 20 MHz vs 16 MHz speed grade (vs. ATMEGA644P-20AU)
  • Larger memory option in same TQFP-44 footprint (vs. ATMEGA1284P-AU)

Designhinweise

The ATMEGA644P-15AT operates from 2.7 V to 5.5 V; AVCC must track VCC within +/- 0.3 V to keep the ADC reference valid. Place a 100 nF decoupling capacitor close to each VCC/AVCC pin, plus a bulk 10 uF tantalum or ceramic near the package. The MCU supports several sleep modes (Idle, ADC Noise Reduction, Power-save, Power-down, Standby, Extended Standby) drawing as little as sub-1 uA in Power-down; wake on Watchdog or external interrupt. The picoPower features on the PA successor lower active current by 25-50% versus the P die. For battery-powered designs, switch the PA family; for line-powered designs the P is fine.

The 44-pin TQFP package has 0.8 mm pitch - manageable for hand-soldering but requires a precise reflow profile for production. Use a 4-layer PCB with a continuous ground plane beneath the part; route ADC traces away from digital switching lines and keep the AVCC trace short and wide. The exposed pad (if present on the QFN variant) must be soldered to the ground plane for thermal dissipation. Crystal traces should be short and symmetric, with the load capacitors placed close to XTAL1/XTAL2. Place the ISP 6-pin header near the MCU to avoid long programming-cable traces that pick up noise.

Common pitfalls with the ATMEGA644P-15AT: (1) forget that the part needs a reset decoupling capacitor on pin 42 (typically 10 kohm pull-up + 100 nF to ground for an RC delay); (2) ignore the fuse settings - the default clock source is the internal 8 MHz RC oscillator, not an external crystal; configure the appropriate low-power crystal fuse bits before relying on accurate timing; (3) leave Brown-Out Detector disabled - enable BOD for robust industrial behavior; (4) use the wrong ISP signature - the ATmega644P and ATmega644A signatures differ, ensure your IDE/compiler is pointed at the correct device; (5) confuse the ATmega644 (single USART) with the ATmega644P (dual USART) - verify the part marking; (6) place too much code in the bootloader section and overflow into application Flash; (7) the 2 KB EEPROM supports 100k write cycles - design firmware to write sparingly and use wear-leveling for parameters that change often.

Compliance-Informationen

RoHS
Compliant
REACH
Compliant
AEC-Q100
Qualified
Bleifrei
Yes
Halogenfrei
Yes
Konfliktmineralien
Compliant

AEC-Q100 Grade 1 qualified per Microchip qualification documentation. RoHS and REACH compliant per DigiKey and Mouser listings. Halogen-free per Atmel/Microchip product environmental compliance documentation.

Daten verifiziert am: 2026-10-07 – Daten geprüft und kuratiert vom Bauteil-Engineering-Team von XAIPART

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