AK6516CF EEPROM 256Kbit SPI Equivalent & Substitute Parts

Part Overview

The AK6516CF is a 256Kbit EEPROM memory IC manufactured by Asahi Kasei Microdevices (AKM) with SPI interface operating at 10 MHz. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity. The part is supplied in 8-SOP packaging and operates across a wide voltage range of 1.6V to 5.5V with temperature stability from -40°C to 85°C.

Key Parameters

Parameter	Value
Memory Type	Non-Volatile EEPROM
Memory Size	256Kbit
Memory Organization	32K x 8
Memory Interface	SPI
Clock Frequency	10 MHz
Voltage Supply Range	1.6V ~ 5.5V
Operating Temperature	-40°C ~ 85°C
Package Type	8-SOP / 8-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
Moisture Sensitivity Level	MSL 1 (Unlimited)

Substitute Part Grouping Explanation

Substitution of the AK6516CF is determined by strict equivalence across the following electrical and mechanical parameters:

Memory capacity: 256Kbit (32K x 8 organization)
Interface protocol: SPI
Operating frequency: 10 MHz
Supply voltage compatibility: Minimum 1.6V to maximum 5.5V
Temperature range: -40°C to 85°C
Package form factor: 8-pin SOP/SOIC with 0.154" (3.90mm) width
Surface mount technology

The identified substitute parts maintain full compatibility across these parameters, enabling direct replacement in circuit designs without modification to PCB layout or firmware interfaces.

Parameter Comparison

Parameter	AK6516CF (Main)	25AA256T-I/SN	S-25C256A0I-J8T1U4
Manufacturer	Asahi Kasei Microdevices	Microchip Technology	ABLIC Inc.
Memory Size	256Kbit	256Kbit	256Kbit
Memory Organization	32K x 8	32K x 8	32K x 8
Memory Interface	SPI	SPI	SPI
Clock Frequency	10 MHz	10 MHz	10 MHz
Voltage Supply Range	1.6V ~ 5.5V	1.8V ~ 5.5V	1.6V ~ 5.5V
Operating Temperature	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C
Package / Case	8-SOP	8-SOIC	8-SOP
Mounting Type	Surface Mount	Surface Mount	Surface Mount
Write Cycle Time	Not specified	5ms	5ms
Product Status	Obsolete	Active	Active
Moisture Sensitivity Level	MSL 1	MSL 1	MSL 1
RoHS Status	Not specified	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

25AA256T-I/SN (Microchip Technology) is the manufacturer-recommended primary substitute. This part maintains full electrical compatibility with the AK6516CF across all critical parameters. The 25AA256T-I/SN is in active production status with verified DiGi-Electronics programmability. The minimum supply voltage is 1.8V compared to the AK6516CF's 1.6V; applications requiring operation below 1.8V must use the S-25C256A0I-J8T1U4 alternative. The 25AA256T-I/SN is supplied in 8-SOIC packaging and carries ROHS3 compliance certification.

S-25C256A0I-J8T1U4 (ABLIC Inc.) is the secondary substitute option. This part matches the AK6516CF across all electrical parameters including the full 1.6V to 5.5V supply voltage range and maintains the 8-SOP package form factor. The S-25C256A0I-J8T1U4 is in active production with ROHS3 compliance. DiGi-Electronics programmability is not verified for this part.

Both substitute parts are actively manufactured, carry MSL 1 moisture sensitivity ratings, and maintain identical memory capacity, organization, interface protocol, and operating temperature specifications as the obsolete AK6516CF.

Frequently Asked Questions (FAQ)

Q: Can the 25AA256T-I/SN directly replace the AK6516CF on existing PCBs?

A: The 25AA256T-I/SN is electrically compatible but uses 8-SOIC packaging versus the AK6516CF's 8-SOP packaging. Both packages have identical 0.154" (3.90mm) width and 8-pin configuration, making them footprint-compatible on standard PCB layouts. Verify your PCB design accommodates SOIC pinout before implementation.

Q: What is the voltage compatibility difference between the two substitutes?

A: The 25AA256T-I/SN operates from 1.8V to 5.5V, while the S-25C256A0I-J8T1U4 operates from 1.6V to 5.5V. If your application requires operation below 1.8V, the S-25C256A0I-J8T1U4 is the required selection. Both parts maintain full compatibility at voltages between 1.8V and 5.5V.

Q: Are both substitute parts RoHS compliant?

A: Yes, both the 25AA256T-I/SN and S-25C256A0I-J8T1U4 carry ROHS3 compliance certification. The original AK6516CF RoHS status is not specified in available documentation.

Q: What is the significance of DiGi-Electronics programmability verification?

A: The 25AA256T-I/SN carries verified DiGi-Electronics programmability, indicating confirmed compatibility with standard programming equipment and procedures. The S-25C256A0I-J8T1U4 programmability is not verified; confirm compatibility with your specific programming tools before production implementation.

Q: Do the substitute parts have identical SPI interface timing?

A: All three parts operate at 10 MHz clock frequency with identical SPI interface protocol. The 25AA256T-I/SN and S-25C256A0I-J8T1U4 both specify 5ms write cycle time. The AK6516CF write cycle time is not specified. Verify your firmware timing assumptions against the documented 5ms specification for substitute parts.

Q: What inventory availability should I expect?

A: The AK6516CF (obsolete) has 751 pieces in stock. The 25AA256T-I/SN (active) has 1,319 pieces available. The S-25C256A0I-J8T1U4 (active) has 8,200 pieces available. Active production parts offer superior long-term availability for ongoing production requirements.

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