AT34C02CY6-YH-T EEPROM Memory IC Equivalent & Substitute Parts

Part Overview

The AT34C02CY6-YH-T is a 2Kbit I2C EEPROM memory IC manufactured by Microchip Technology, featuring a 256 x 8 memory organization with 400 kHz clock frequency and 900 ns access time. This part is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity. The device operates across a wide voltage range of 1.7V to 5.5V and supports industrial temperature ranges from -40°C to 85°C.

Key Parameters

Parameter	Value
Memory Size	2Kbit
Memory Organization	256 x 8
Memory Interface	I2C
Clock Frequency	400 kHz
Access Time	900 ns
Write Cycle Time	5 ms
Voltage Supply Range	1.7V ~ 5.5V
Operating Temperature	-40°C ~ 85°C
Package Type	8-UFDFN Exposed Pad
Mounting Type	Surface Mount
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitute parts for the AT34C02CY6-YH-T are classified based on strict adherence to the following critical parameters:

Primary Substitution Criteria:

Memory Size: 2Kbit (non-negotiable)
Memory Organization: 256 x 8 (non-negotiable)
Memory Interface: I2C (non-negotiable)
Voltage Supply Range: 1.7V ~ 5.5V (non-negotiable)
Operating Temperature: -40°C ~ 85°C (non-negotiable)
Write Cycle Time: 5 ms (non-negotiable)

Secondary Compatibility Parameters:

Clock Frequency: 400 kHz (primary specification) or higher
Access Time: 900 ns (primary specification) or faster
Package Type: 8-pin surface mount variants (8-UFDFN, 8-UDFN, 8-TDFN, 8-UFDFPN)
RoHS Compliance: ROHS3 Compliant

Substitutes are grouped into two categories: Direct Manufacturer Alternatives (same manufacturer, active product status) and Parametric Equivalents (alternative manufacturers, matching or exceeding electrical specifications).

Parameter Comparison

Part Number	Manufacturer	Memory Size	Clock Frequency	Access Time	Voltage Supply	Operating Temp	Package	Product Status	MSL Rating
AT34C02CY6-YH-T	Microchip Technology	2Kbit	400 kHz	900 ns	1.7V ~ 5.5V	-40°C ~ 85°C	8-UFDFN	Obsolete	1 (Unlimited)
AT34C02D-MAHM-T	Microchip Technology	2Kbit	1 MHz	N/A	1.7V ~ 5.5V	-40°C ~ 85°C	8-UDFN	Active	3 (168 Hours)
34AA02T-I/MNY	Microchip Technology	2Kbit	400 kHz	900 ns	1.7V ~ 5.5V	-40°C ~ 85°C	8-TDFN	Active	1 (Unlimited)
CAT34C02HU4IGT4A	onsemi	2Kbit	400 kHz	900 ns	1.7V ~ 5.5V	-40°C ~ 85°C	8-UDFN-EP	Active	1 (Unlimited)
CAT34C02HU4IGT4U5	onsemi	2Kbit	400 kHz	900 ns	1.7V ~ 5.5V	-40°C ~ 85°C	8-UDFN	Active	1 (Unlimited)
M24C02-FMC6TG	STMicroelectronics	2Kbit	400 kHz	900 ns	1.7V ~ 5.5V	-40°C ~ 85°C	8-UFDFPN	Active	1 (Unlimited)
M34E02-FMC6TG	STMicroelectronics	2Kbit	400 kHz	900 ns	1.7V ~ 5.5V	-40°C ~ 85°C	8-UFDFPN	Active	1 (Unlimited)

Engineering Selection Recommendations

Direct Manufacturer Substitutes (Microchip Technology):

AT34C02D-MAHM-T is the primary direct substitute from Microchip Technology with active product status. This part maintains identical memory capacity, voltage range, and operating temperature specifications. The clock frequency is increased to 1 MHz, providing enhanced performance headroom. The MSL rating of 3 (168 Hours) indicates standard moisture sensitivity compared to the original part's MSL 1 rating. This part is suitable for applications requiring higher I2C bus speeds while maintaining full backward compatibility.

34AA02T-I/MNY is the manufacturer-recommended substitute, offering identical electrical specifications to the original part including 400 kHz clock frequency and 900 ns access time. The package variant (8-TDFN) differs from the original 8-UFDFN but maintains the same 2x3 mm footprint dimensions. MSL rating of 1 (Unlimited) matches the original part. This option is optimal for direct functional replacement with minimal design modification.

Parametric Equivalents (Alternative Manufacturers):

CAT34C02HU4IGT4U5 and CAT34C02HU4IGT4A from onsemi are parametric equivalents meeting all electrical specifications of the original part. Both devices feature 400 kHz clock frequency, 900 ns access time, and MSL 1 rating. The primary difference is package designation (8-UDFN versus 8-UDFN-EP). Both parts are in active production status with substantial inventory availability.

M24C02-FMC6TG and M34E02-FMC6TG from STMicroelectronics are parametric equivalents with identical electrical performance specifications. Both parts feature 400 kHz clock frequency, 900 ns access time, and MSL 1 rating. The package variant (8-UFDFPN) is mechanically compatible with the original 8-UFDFN specification. Both parts maintain active product status with high inventory levels.

Selection Criteria:

For applications requiring immediate substitution with minimal design changes, select 34AA02T-I/MNY or M24C02-FMC6TG. For applications benefiting from higher I2C bus speeds, select AT34C02D-MAHM-T. For multi-source qualification, select from the onsemi or STMicroelectronics parametric equivalents. All recommended substitutes maintain ROHS3 compliance and EAR99 export classification.

Frequently Asked Questions (FAQ)

Q: Can AT34C02D-MAHM-T be used as a direct replacement for AT34C02CY6-YH-T?

A: Yes, AT34C02D-MAHM-T is functionally compatible. The 1 MHz clock frequency is backward compatible with 400 kHz I2C bus operation. The MSL rating difference (3 versus 1) requires evaluation based on storage and assembly conditions. Package footprint remains identical at 2x3 mm.

Q: What is the difference between the onsemi CAT34C02HU4IGT4U5 and CAT34C02HU4IGT4A variants?

A: Both parts are electrically identical with matching specifications. The primary difference is the package designation suffix: CAT34C02HU4IGT4U5 uses standard 8-UDFN, while CAT34C02HU4IGT4A uses 8-UDFN-EP (exposed pad variant). The exposed pad in the EP version provides improved thermal performance. Select based on PCB layout requirements and thermal management needs.

Q: Are STMicroelectronics M24C02-FMC6TG and M34E02-FMC6TG interchangeable?

A: Yes, both parts are parametrically identical with matching electrical specifications, clock frequency, access time, and voltage range. The base part numbers differ (M24C02 versus M34E02), but functional performance is equivalent. Selection can be based on availability and supply chain considerations.

Q: What is the impact of MSL rating differences between substitute parts?

A: MSL (Moisture Sensitivity Level) rating indicates moisture absorption limits during storage and assembly. The original part and most substitutes carry MSL 1 (Unlimited), meaning no moisture precautions are required. AT34C02D-MAHM-T carries MSL 3 (168 Hours), requiring dry storage and limiting floor life after moisture exposure. For standard manufacturing environments, this difference is typically not critical.

Q: Can these I2C EEPROM substitutes operate at different I2C bus speeds?

A: Yes, all substitute parts support I2C operation at speeds up to their specified clock frequency. The original part and most substitutes are rated for 400 kHz operation. AT34C02D-MAHM-T supports up to 1 MHz. All parts are backward compatible with lower bus speeds. System design must ensure pull-up resistor values and bus capacitance comply with I2C specifications for the selected operating frequency.

Q: Are all substitute parts RoHS3 compliant?

A: Yes, all listed substitute parts maintain ROHS3 compliance matching the original AT34C02CY6-YH-T specification. All parts are also REACH Unaffected and classified as EAR99 for export purposes.

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