AT89LS53-12AC Equivalent & Substitute Parts

Part Overview

The AT89LS53-12AC is an 8051-based 8-bit microcontroller manufactured by Microchip Technology, featuring 12KB FLASH program memory, 256 bytes of RAM, and 32 I/O pins in a 44-TQFP surface mount package. This device operates at 12MHz with a supply voltage range of 2.7V to 6V and includes integrated peripherals such as SPI and UART/USART connectivity, Power-On Reset (POR), and Watchdog Timer (WDT).

The AT89LS53-12AC is classified as obsolete. Locating equivalent or substitute components is necessary for ongoing system maintenance, design updates, or when original inventory becomes unavailable. Substitute parts must maintain core functional compatibility while meeting current application requirements.

Key Parameters

Parameter	AT89LS53-12AC
Core Processor	8051
Core Size	8-Bit
Program Memory Size	12KB (12K x 8)
Program Memory Type	FLASH
RAM Size	256 x 8
Number of I/O	32
Speed	12MHz
Voltage - Supply (Vcc/Vdd)	2.7V ~ 6V
Connectivity	SPI, UART/USART
Peripherals	POR, WDT
Package / Case	44-TQFP (10x10)
Mounting Type	Surface Mount
Operating Temperature	0°C ~ 70°C (TA)

Substitute Part Grouping Explanation

Substitution eligibility for the AT89LS53-12AC is determined by the following critical parameters:

Core Processor Architecture: Must be 8051-compatible
Core Size: Must be 8-Bit
Program Memory Size: Must be 12KB (12K x 8) FLASH
RAM Size: Must be 256 x 8
Number of I/O: Must be 32
Package / Case: Must be 44-TQFP (10x10)
Mounting Type: Must be Surface Mount
Connectivity: Must include SPI and UART/USART
Peripherals: Must include POR and WDT

The AT89S8253-24AU meets all core substitution criteria. While it operates at a higher clock speed (24MHz) and includes additional EEPROM (2K x 8), these enhancements do not prevent functional substitution. The device maintains identical pin count, package form factor, memory architecture, and peripheral set.

Parameter Comparison

Parameter	AT89LS53-12AC	AT89S8253-24AU
Manufacturer	Microchip Technology	Microchip Technology
Core Processor	8051	8051
Core Size	8-Bit	8-Bit
Program Memory Size	12KB (12K x 8)	12KB (12K x 8)
Program Memory Type	FLASH	FLASH
RAM Size	256 x 8	256 x 8
EEPROM Size	Not specified	2K x 8
Number of I/O	32	32
Speed	12MHz	24MHz
Voltage - Supply (Vcc/Vdd)	2.7V ~ 6V	2.7V ~ 5.5V
Connectivity	SPI, UART/USART	SPI, UART/USART
Peripherals	POR, WDT	POR, WDT
Oscillator Type	Internal	External
Operating Temperature	0°C ~ 70°C (TA)	-40°C ~ 85°C (TA)
Package / Case	44-TQFP (10x10)	44-TQFP (10x10)
Mounting Type	Surface Mount	Surface Mount
Product Status	Obsolete	Active
RoHS Status	RoHS non-compliant	ROHS3 Compliant

Engineering Selection Recommendations

The AT89S8253-24AU is an active product with ROHS3 compliance, whereas the AT89LS53-12AC is obsolete and RoHS non-compliant. For new designs or systems requiring regulatory compliance, the AT89S8253-24AU is the appropriate selection. The substitute part maintains identical core memory architecture, I/O count, and peripheral functionality.

Designers must account for the following differences when implementing the AT89S8253-24AU:

Supply voltage range is narrower (2.7V ~ 5.5V versus 2.7V ~ 6V)
Operating temperature range is extended (-40°C ~ 85°C versus 0°C ~ 70°C)
Clock speed is doubled (24MHz versus 12MHz), requiring timing-dependent code review
Oscillator configuration differs (external versus internal)
Additional 2K x 8 EEPROM is available

Frequently Asked Questions (FAQ)

Q: Can the AT89S8253-24AU directly replace the AT89LS53-12AC without code modifications?

A: The AT89S8253-24AU maintains identical pin configuration, package form factor, and core instruction set compatibility. However, the doubled clock speed (24MHz versus 12MHz) affects timing-dependent operations. Code utilizing delay loops, baud rate calculations, or timer-based functions requires review and adjustment to account for the faster execution speed.

Q: What is the difference between internal and external oscillator configuration?

A: The AT89LS53-12AC uses an internal oscillator, while the AT89S8253-24AU requires an external oscillator. System designs must include appropriate external crystal or clock source components when implementing the substitute part.

Q: Are the pin assignments identical between these two parts?

A: Yes. Both devices use the 44-TQFP (10x10) package with identical pin assignments and I/O configuration. PCB layout compatibility is maintained.

Q: What is the significance of ROHS3 compliance?

A: ROHS3 compliance indicates the AT89S8253-24AU meets current environmental and regulatory standards for hazardous substance restrictions. The obsolete AT89LS53-12AC does not meet these requirements. For applications subject to regulatory compliance mandates, the substitute part is necessary.

Q: Does the additional 2K x 8 EEPROM in the AT89S8253-24AU affect compatibility?

A: The additional EEPROM is a functional enhancement and does not impact compatibility. Existing code operates without modification. Applications may optionally utilize the additional EEPROM for expanded data storage.

Q: What supply voltage considerations apply when substituting these parts?

A: The AT89S8253-24AU operates within 2.7V ~ 5.5V, which is a subset of the AT89LS53-12AC range (2.7V ~ 6V). Systems operating above 5.5V require voltage regulation or redesign to accommodate the substitute part.

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