FM93C86AM8 EEPROM 16Kbit Microwire Equivalent & Substitute Parts

Part Overview

The FM93C86AM8 is a 16Kbit non-volatile EEPROM memory IC manufactured by onsemi, featuring Microwire serial interface protocol and 8-SOIC surface mount packaging. This device operates at 1 MHz clock frequency with a 10ms write cycle time and requires 4.5V to 5.5V supply voltage. The FM93C86AM8 is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity.

Key Parameters

Parameter	FM93C86AM8 Specification
Memory Size	16Kbit
Memory Organization	2K x 8, 1K x 16
Memory Interface	Microwire
Clock Frequency	1 MHz
Write Cycle Time	10ms
Supply Voltage Range	4.5V ~ 5.5V
Operating Temperature	0°C ~ 70°C
Package / Case	8-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution for the FM93C86AM8 is determined by the following critical parameters:

Memory Capacity & Organization: All substitute parts must provide 16Kbit capacity with 2K x 8 or 1K x 16 organization to maintain functional equivalence.

Serial Interface Protocol: The FM93C86AM8 uses Microwire protocol. Substitutes are grouped into two categories:

Microwire-compatible devices (M93C86 series from STMicroelectronics)
3-Wire Serial protocol devices (AT93C86A series from Microchip Technology), which provide protocol-level compatibility through standardized serial EEPROM interfaces

Package Compatibility: All substitutes maintain the 8-SOIC (0.154", 3.90mm Width) surface mount package for direct PCB compatibility.

Supply Voltage: Substitutes must support the original 4.5V ~ 5.5V operating range or provide extended voltage ranges that encompass this specification.

Clock Frequency: The FM93C86AM8 operates at 1 MHz. Substitutes operating at 2 MHz or higher maintain backward compatibility through frequency headroom.

Write Cycle Time: All substitutes maintain the 10ms write cycle time specification or improve upon it (5ms for M93C86 series).

Parameter Comparison

Parameter	FM93C86AM8	AT93C86A-10SU-1.8	AT93C86A-10SU-2.7	AT93C86A-10SU-2.7-T	M93C86-RMN3TP/K	M93C86-WMN6TP
Manufacturer	onsemi	Microchip Technology	Microchip Technology	Microchip Technology	STMicroelectronics	STMicroelectronics
Memory Size	16Kbit	16Kbit	16Kbit	16Kbit	16Kbit	16Kbit
Memory Organization	2K x 8, 1K x 16	2K x 8, 1K x 16	2K x 8, 1K x 16	2K x 8, 1K x 16	2K x 8, 1K x 16	2K x 8, 1K x 16
Memory Interface	Microwire	3-Wire Serial	3-Wire Serial	3-Wire Serial	Microwire	Microwire
Clock Frequency	1 MHz	2 MHz	2 MHz	1 MHz	2 MHz	2 MHz
Write Cycle Time	10ms	10ms	10ms	10ms	5ms	5ms
Supply Voltage Range	4.5V ~ 5.5V	1.8V ~ 5.5V	2.7V ~ 5.5V	2.7V ~ 5.5V	1.8V ~ 5.5V	2.5V ~ 5.5V
Operating Temperature	0°C ~ 70°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 125°C	-40°C ~ 85°C
Package / Case	8-SOIC	8-SOIC	8-SOIC	8-SOIC	8-SOIC	8-SOIC
Product Status	Obsolete	Active	Active	Active	Active	Active
RoHS Status	Non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

For Direct Microwire Protocol Replacement:

The M93C86-WMN6TP and M93C86-RMN3TP/K from STMicroelectronics provide direct Microwire interface compatibility with the FM93C86AM8. Both devices are active products with ROHS3 compliance. The M93C86-RMN3TP/K offers extended operating temperature range (-40°C to 125°C) and AEC-Q100 automotive qualification, making it suitable for demanding applications. The M93C86-WMN6TP operates within -40°C to 85°C and provides improved write cycle time (5ms versus 10ms).

For 3-Wire Serial Protocol Substitution:

The AT93C86A series from Microchip Technology provides 16Kbit EEPROM capacity with 3-Wire Serial interface protocol. These devices are active products with ROHS3 compliance and extended operating temperature ranges (-40°C to 85°C). Selection within this series depends on supply voltage requirements:

AT93C86A-10SU-1.8: Supports 1.8V minimum supply voltage for low-power applications
AT93C86A-10SU-2.7: Supports 2.7V minimum supply voltage with unlimited moisture sensitivity rating
AT93C86A-10SU-2.7-T: Tape & Reel packaging variant with 1 MHz clock frequency matching the original device

Compliance Considerations:

All substitute parts are ROHS3 compliant and REACH unaffected, addressing environmental and regulatory requirements that the obsolete FM93C86AM8 does not meet. The M93C86-RMN3TP/K includes AEC-Q100 automotive qualification for applications requiring automotive-grade components.

Frequently Asked Questions (FAQ)

Q: Can the AT93C86A series replace the FM93C86AM8 directly?

A: The AT93C86A series provides functional equivalence in memory capacity, organization, and package, but uses 3-Wire Serial protocol instead of Microwire. Applications using Microwire-specific protocol commands require firmware or controller adaptation. Applications using generic serial EEPROM access patterns can typically accommodate this substitution.

Q: What is the difference between Microwire and 3-Wire Serial protocols?

A: Both are serial EEPROM interface standards. Microwire is a three-wire protocol (Chip Select, Clock, Data In/Out). 3-Wire Serial is also a three-wire protocol with similar pin functionality. The primary difference lies in command structure and timing specifications. Devices are not directly interchangeable at the protocol level without controller firmware modification.

Q: Which substitute offers the best performance improvement?

A: The M93C86-WMN6TP and M93C86-RMN3TP/K reduce write cycle time from 10ms to 5ms and support 2 MHz clock frequency versus 1 MHz, providing 2x performance improvement in write operations and clock speed headroom.

Q: Are all substitutes available in the same packaging?

A: Yes. All substitute parts use 8-SOIC (0.154", 3.90mm Width) surface mount packaging, enabling direct PCB compatibility without layout modifications.

Q: What packaging options are available for the substitute parts?

A: Substitute parts are available in multiple packaging formats: Tube, Cut Tape (CT) & Digi-Reel, and Tape & Reel (TR). Selection depends on production volume and assembly process requirements.

Q: Does the FM93C86AM8 have any active equivalents from onsemi?

A: The FM93C86AM8 is obsolete. onsemi does not list active equivalent products. Substitution requires selection from Microchip Technology (AT93C86A series) or STMicroelectronics (M93C86 series).

Q: What is the temperature operating range difference?

A: The FM93C86AM8 operates 0°C to 70°C. All substitute parts extend this range to -40°C to 85°C (or -40°C to 125°C for M93C86-RMN3TP/K), providing broader environmental compatibility.

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