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Home Products Integrated Circuits (ICs)Embedded - Microcontrollers~~AT89C51RE2-RLTUM~~

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AT89C51RE2-RLTUM - Microchip Technology

Manufacturer Part Number: AT89C51RE2-RLTUM

Manufacturer: Microchip Technology

Allelco Part Number: 98D-AT89C51RE2-RLTUM

Warranty: 1 Year Allelco Warranty - Find out more

Stock Status:: 7,161 pcs available, New & Original

Parts Description: IC MCU 8BIT 128KB FLASH 44VQFP

Package: 44-VQFP (10x10)

Data sheet: AT89C51RE2-RLTU.pdf

Datasheets
AT89C51RE2.pdf

PCN Packaging
Transfer to Microchip/Label/Pkg 5/Sep/2016.pdf MBB/Label Chgs 16/Nov/2018.pdf

PCN Obsolescence/ EOL
Multiple Devices 28/Aug/2013.pdf

RoHs Status: ROHS3 Compliant

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In stock: 7161

Specifications

AT89C51RE2-RLTUM Tech Specifications
Microchip Technology - AT89C51RE2-RLTUM technical specifications, attributes, parameters and parts with similar specifications to Microchip Technology - AT89C51RE2-RLTUM

Product Attribute	Attribute Value
Manufacturer	Microchip Technology
Voltage - Supply (Vcc/Vdd)	2.7V ~ 5.5V
Supplier Device Package	44-VQFP (10x10)
Speed	60MHz
Series	89C
RAM Size	8K x 8
Program Memory Type	FLASH
Program Memory Size	128KB (128K x 8)
Peripherals	POR, PWM, WDT
Package / Case	44-LQFP
Package	Tray

Product Attribute	Attribute Value
Oscillator Type	External
Operating Temperature	-40°C ~ 85°C (TA)
Number of I/O	34
Mounting Type	Surface Mount
EEPROM Size	-
Data Converters	-
Core Size	8-Bit
Core Processor	80C51
Connectivity	I²C, SPI, UART/USART
Base Product Number	AT89C51RE2

Environmental & Export Classifications

ATTRIBUTE	DESCRIPTION
RoHs Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	3 (168 Hours)
REACH Status	REACH Unaffected
ECCN	3A991A2
HTSUS	8542.31.0001

Frequently Asked Questions(FAQ)

How does the AT89C51RE2-RLTUM compare to other 80C51 family microcontrollers in terms of program memory capacity and operating voltage range?: The AT89C51RE2-RLTUM offers a significant advantage over earlier 80C51 variants by providing 128KB of on-chip Flash program memory, which is four times larger than the typical 32KB found in standard 89C51 models. This expanded memory enables implementation of more complex firmware routines without external memory components. While many legacy 80C51 devices operate at 5V only, this part supports a wider supply voltage range from 2.7V to 5.5V, offering improved compatibility with low-power battery-operated systems and mixed-voltage environments common in modern embedded designs.

What are the key differences between the AT89C51RE2-RLTUM and similar 8-bit MCUs when considering peripheral integration for industrial sensor monitoring applications?: For industrial sensor monitoring where reliability and integration density matter, the AT89C51RE2-RLTUM stands out due to its combination of 34 I/O pins, built-in power-on reset (POR), watchdog timer (WDT), and PWM peripherals—all within a single 44-pin package. Unlike discrete solutions requiring multiple ICs for basic control functions, this MCU integrates essential features that reduce component count and board space. The presence of UART, SPI, and I2C interfaces allows direct connectivity to various sensors without additional protocol converters, making it particularly suitable for distributed sensing networks where cost and footprint are critical.

Can the AT89C51RE2-RLTUM reliably operate in harsh environmental conditions typically encountered in automotive or outdoor instrumentation?: While the AT89C51RE2-RLTUM is rated for commercial temperature operation (-40°C to 85°C), it falls short of full automotive-grade qualification (which usually requires -40°C to +125°C). Therefore, it may not be appropriate for primary automotive safety systems but could be viable for non-critical instrumentation in controlled outdoor environments where temperatures remain within specification. Designers should verify actual operating conditions against the absolute maximum ratings and consider thermal management strategies if ambient temperatures approach the upper limit.

What impact does the 60MHz clock speed have on real-world performance when running typical C-compiled code on the AT89C51RE2-RLTUM?: The 60MHz maximum frequency provides substantial headroom for computationally intensive tasks compared to older 12–24MHz 80C51 implementations. In practice, most C-code compiled for the 80C51 architecture executes at one instruction per machine cycle under optimal conditions. This means 60MHz translates to approximately 60 million instructions per second—enough to handle moderate data processing, communication protocols, or algorithm execution without bottlenecking. However, actual throughput depends heavily on compiler efficiency, code optimization, and wait states introduced by slower external memory accesses.

Is it possible to upgrade firmware in-field using the AT89C51RE2-RLTUM’s Flash memory, and what precautions should be taken?: Yes, the AT89C51RE2-RLTUM supports in-system programming (ISP) via its standard serial interface, allowing field firmware updates without removing the device from the PCB. However, proper erase/write cycles must be followed: the entire page or sector must be erased before rewriting, and the programmer must respect timing constraints during erase operations. Additionally, bootloader software must be pre-installed to manage update sequences safely. Failure to follow these steps risks corrupting the application code or rendering the device unrecoverable.

How does the AT89C51RE2-RLTUM compare to newer ARM Cortex-M0+ based MCUs in terms of power consumption and development complexity?: While the AT89C51RE2-RLTUM consumes less static current than many ARM-based alternatives, its 80C51 architecture lacks advanced sleep modes and dynamic voltage scaling available in modern low-power MCUs. From a development standpoint, the 80C51 toolchain is mature and widely supported, whereas ARM ecosystems offer richer debugging tools but steeper learning curves. For simple control loops or legacy system migration, the AT89C51RE2-RLTUM remains efficient; however, for energy-sensitive or signal-processing-intensive applications, ARM-based solutions generally provide better long-term scalability.

What considerations apply when designing PCB layouts for the AT89C51RE2-RLTUM to ensure stable operation with its external oscillator requirement?: Since the AT89C51RE2-RLTUM requires an external crystal or resonator, careful attention must be paid to layout parasitics near the XTAL1 and XTAL2 pins. Keep traces short, avoid routing over split planes, and use load capacitors matched to the crystal’s specified values. A ground plane beneath the oscillator section improves stability and reduces EMI susceptibility. Additionally, decoupling capacitors (typically 100nF ceramic) should be placed as close as possible to the Vcc and GND pins of the MCU to suppress high-frequency noise that could disrupt oscillator startup or introduce jitter.

Why might someone choose the AT89C51RE2-RLTUM over a microcontroller with integrated analog peripherals like ADCs or DACs?: If the application doesn’t require precise analog measurement or generation, the absence of built-in ADCs or DACs in the AT89C51RE2-RLTUM can actually simplify the design by eliminating redundant circuitry and reducing pin count allocation. External precision ADCs or DACs offer superior resolution, linearity, and reference stability compared to internal implementations. This separation also allows selection of dedicated analog ICs tailored to specific accuracy requirements, avoiding compromises inherent in mixed-signal MCUs where digital noise affects analog performance.

Parts with Similar Specifications

The three parts on the right have similar specifications to Microchip Technology AT89C51RE2-RLTUM

Product Attribute
Part Number	AT89C51RD2T-RLTUMA0	AT89C51RD2T-RLTUM	AT89C51RE2-SLRUM	AT89C51RE2-SLSUM
Manufacturer	Microchip Technology	Microchip Technology	Microchip Technology	Microchip Technology
Number of I/O	-	-	-	-
Operating Temperature	-	-40°C ~ 85°C	0°C ~ 70°C	-40°C ~ 85°C
Base Product Number	-	DAC34H84	MAX500	ADS62P42
Core Size	-	-	-	-
EEPROM Size	-	-	-	-
Data Converters	-	-	-	-
Supplier Device Package	-	196-NFBGA (12x12)	16-PDIP	64-VQFN (9x9)
Program Memory Size	-	-	-	-
Voltage - Supply (Vcc/Vdd)	-	-	-	-
Core Processor	-	-	-	-
Series	-	-	-	-
Package	-	Tape & Reel (TR)	Tube	Tape & Reel (TR)
Peripherals	-	-	-	-
Mounting Type	-	Surface Mount	Through Hole	Surface Mount
RAM Size	-	-	-	-
Connectivity	-	-	-	-
Package / Case	-	196-LFBGA	16-DIP (0.300', 7.62mm)	64-VFQFN Exposed Pad
Speed	-	-	-	-
Oscillator Type	-	-	-	-
Program Memory Type	-	-	-	-

AT89C51RE2-RLTUM Datasheet PDF

Download AT89C51RE2-RLTUM pdf datasheets and Microchip Technology documentation for AT89C51RE2-RLTUM - Microchip Technology.

Datasheets: AT89C51RE2.pdf
PCN Packaging: Transfer to Microchip/Label/Pkg 5/Sep/2016.pdf MBB/Label Chgs 16/Nov/2018.pdf
PCN Obsolescence/ EOL: Multiple Devices 28/Aug/2013.pdf

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Customer Reviews

Evaluation: 10 Articles

Nath***rooks

Jun 11, 2026

Installed this power component in a converter board. Output remained stable under different load conditions and thermal performance was better than expected.
Dani***alkerTech

Jun 1, 2026

Product works, but setup took more effort than expected. Once configured the MCU ran reliably, although documentation support felt older compared with newer platforms. Fine for maintenance projects.
Yuki***aka88

May 26, 2026

信号通信プロジェクトでこのRS-485トランシーバーを使用しました。設置は簡単で、長距離ケーブルでも通信は安定していました。消費電力も、以前使用していたものより低くなっています。
Stev***aker

May 20, 2026

Solid diode for power rectification. Works well in switching circuits.
Bran***Lewis

May 11, 2026

Compact FPGA with good performance. Suitable for basic signal processing tasks.
Oliv***arris

May 7, 2026

Reliable I/O expander. Works well in embedded control applications.
Jess***Jones

Apr 17, 2026

It offers good value for the price, and the specifications match the description. I’ve been using it for two days with no issues, and I’ll definitely buy it again if I need it in the future.
Mich***Smith

Apr 17, 2026

Shipping was on time, the component pins are neatly aligned, and I tested 10 of them with a multimeter—all readings were within the specified range. Highly recommended.
Aman***arris

Apr 3, 2026

It was great—the entire process, from placing the order to receiving the package, went very smoothly. The components were consistent, the price was fair, and I had a very pleasant shopping experience.
Mike***nch

Apr 3, 2026

Better than expected! The resistance and capacitance readings were spot-on, and it passed the test on the first try. The service was reliable, and the packaging was thoughtful—I highly recommend it.

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Common Countries Logistic Time Reference
Region	Country	Logistic Time(Day)
America	United States	5
America	Brazil	7
Europe	Germany	5
	United Kingdom	4
	Italy	5
Oceania	Australia	6
Oceania	New Zealand	5
Asia	India	4
Asia	Japan	4
Middle East	Israel	6

DHL & FedEx Shipment Charges Reference
Shipment charges(KG)	Reference DHL(USD$)
0.00kg-1.00kg	USD$30.00 - USD$60.00
1.00kg-2.00kg	USD$40.00 - USD$80.00
2.00kg-3.00kg	USD$50.00 - USD$100.00

Note:: The above table is for reference only. There may have some data bias for the uncontrollable factors.
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