DS1225AD-85 NVSRAM 64Kbit Parallel Memory IC Equivalent & Substitute Parts

Part Overview

The DS1225AD-85 is a Non-Volatile SRAM (NVSRAM) memory integrated circuit manufactured by Analog Devices Inc./Maxim Integrated. This 64Kbit parallel memory device operates with an 85 nanosecond access time and is housed in a 28-pin DIP package. The part is currently classified as obsolete, making equivalent and substitute parts necessary for system maintenance, repair, and legacy equipment support. Substitute parts must maintain functional compatibility across memory capacity, interface type, electrical specifications, and physical packaging.

Substiute Parts

DS1225AD-85

Analog Devices Inc./Maxim IntegratedIn Stock: 2596DS1225AD-85 Datasheet

Current PartRFQ

DS1225AD-70+

Analog Devices Inc./Maxim IntegratedIn Stock: 2751DS1225AD-70+ Datasheet

DirectRFQ

DS1225AD-85+

Analog Devices Inc./Maxim IntegratedIn Stock: 1967DS1225AD-85+ Datasheet

DirectRFQ

M48Z18-100PC1

STMicroelectronicsIn Stock: 1651M48Z18-100PC1 Datasheet

MFR RecommendedRFQ

M48Z58Y-70PC1

STMicroelectronicsIn Stock: 2897M48Z58Y-70PC1 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution compatibility for the DS1225AD-85 is determined by the following critical parameters:

Memory Specifications: All substitute parts must provide 64Kbit capacity in 8K x 8 organization with parallel interface to ensure functional equivalence in data storage and retrieval operations.

Electrical Compatibility: Supply voltage range (4.5V ~ 5.5V) and operating temperature range (0°C ~ 70°C) must be maintained across all substitutes to ensure operation within the same system power and thermal constraints.

Physical Packaging: All substitutes must use 28-pin DIP package format with 0.600" (15.24mm) spacing to ensure direct socket compatibility and PCB layout compatibility without redesign.

Access Time Consideration: The DS1225AD-85 specifies 85 nanosecond access time. Substitute parts with equal or faster access times (70 ns or 100 ns) are functionally compatible, as faster devices do not create timing violations in systems designed for 85 ns operation.

Product Status: Active product status indicates current manufacturing and availability, whereas obsolete status indicates end-of-life designation.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitute (Same Manufacturer, Same Speed): DS1225AD-85+ is the direct equivalent to DS1225AD-85. Both parts share identical memory specifications, access time, and package format. DS1225AD-85+ carries active product status and RoHS3 compliance, providing current manufacturing support and regulatory alignment.

Alternative Substitute (Same Manufacturer, Faster Speed): DS1225AD-70+ offers improved performance with 70 nanosecond access time while maintaining all other electrical and physical specifications. This part is active and RoHS3 compliant. The faster access time creates no compatibility issues in systems designed for 85 ns operation.

Cross-Manufacturer Substitutes (STMicroelectronics): M48Z18-100PC1 and M48Z58Y-70PC1 provide functional equivalence with identical memory capacity, organization, and electrical specifications. Both use 28-PCDIP package format with CAPHAT® technology. M48Z58Y-70PC1 offers 70 nanosecond access time, while M48Z18-100PC1 operates at 100 nanoseconds. Both parts are active and RoHS3 compliant.

Compliance Consideration: All substitute parts listed carry RoHS3 compliance status, whereas the original DS1225AD-85 is RoHS non-compliant. Selection of RoHS3 compliant substitutes aligns with current regulatory requirements for new equipment and repairs.

Frequently Asked Questions (FAQ)

Q: Can DS1225AD-85+ directly replace DS1225AD-85 without PCB modification?

A: Yes. DS1225AD-85+ maintains identical memory capacity (64Kbit), organization (8K x 8), electrical specifications (4.5V ~ 5.5V supply, 0°C ~ 70°C operating range), and 28-EDIP package format. Direct socket substitution is possible without PCB redesign.

Q: What is the difference between DS1225AD-70+ and DS1225AD-85+?

A: Both parts are functionally equivalent with identical memory specifications and packaging. The primary difference is access time: DS1225AD-70+ operates at 70 nanoseconds while DS1225AD-85+ operates at 85 nanoseconds. The faster DS1225AD-70+ is compatible in any application designed for 85 ns operation.

Q: Are STMicroelectronics M48Z18 and M48Z58 series parts compatible with Analog Devices DS1225AD?

A: Yes, within specified parameters. Both M48Z18-100PC1 and M48Z58Y-70PC1 provide 64Kbit NVSRAM with 8K x 8 organization, parallel interface, and identical electrical specifications. Package format differs (28-PCDIP versus 28-EDIP), but both are 28-pin DIP modules with 0.600" spacing, allowing socket compatibility on standard through-hole PCBs.

Q: Does faster access time (70 ns vs. 85 ns) create any compatibility issues?

A: No. Faster access time does not create timing violations. Systems designed for 85 nanosecond access time operate correctly with 70 nanosecond devices. The faster device simply responds more quickly than the system timing requirements demand.

Q: What is the significance of RoHS3 compliance on substitute parts?

A: RoHS3 compliance indicates the part meets current Restriction of Hazardous Substances regulations. The original DS1225AD-85 is RoHS non-compliant. Selecting RoHS3 compliant substitutes ensures regulatory alignment for new equipment builds and repairs in jurisdictions with RoHS requirements.

Q: Can M48Z58Y-70PC1 be used in legacy equipment designed for DS1225AD-85?

A: Yes. M48Z58Y-70PC1 provides equivalent memory capacity, organization, electrical specifications, and operating temperature range. The 28-pin DIP package with 0.600" spacing ensures physical compatibility. The 70 nanosecond access time is faster than the original 85 nanosecond specification, creating no timing conflicts.