DS1249AB-85 Equivalent & Substitute Parts

Part Overview

The DS1249AB-85 is a Non-Volatile SRAM (NVSRAM) memory integrated circuit manufactured by Analog Devices Inc./Maxim Integrated. This 2Mbit parallel memory device operates with an 85 nanosecond access time and is housed in a 32-EDIP package. The part is currently classified as obsolete, making identification of compatible substitute components essential for system maintenance, repair, and legacy product support.

Key Parameters

Parameter	Value
Memory Type	Non-Volatile SRAM (NVSRAM)
Memory Size	2Mbit
Memory Organization	256K x 8
Memory Interface	Parallel
Access Time	85 ns
Write Cycle Time	85 ns
Supply Voltage	4.75V ~ 5.25V
Operating Temperature	0°C ~ 70°C
Package Type	32-DIP Module (0.600", 15.24mm)
Mounting Type	Through Hole
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution eligibility for the DS1249AB-85 is determined by strict equivalence across the following critical parameters:

Memory Type: Must be Non-Volatile SRAM (NVSRAM)
Memory Size: Must be 2Mbit
Memory Organization: Must be 256K x 8
Memory Interface: Must be Parallel
Package Type: Must be 32-DIP Module (0.600", 15.24mm)
Supply Voltage: Must be 4.75V ~ 5.25V
Operating Temperature: Must be 0°C ~ 70°C

The DS1249AB-70# qualifies as a direct substitute because it maintains identical memory specifications, organization, interface, packaging, voltage, and temperature ratings. The primary difference is the access time specification: 70 nanoseconds versus 85 nanoseconds. A faster access time (70 ns) is functionally compatible with systems designed for 85 ns operation, as the substitute meets or exceeds the timing requirements of the original part.

Parameter Comparison

Parameter	DS1249AB-85 (Main Part)	DS1249AB-70# (Substitute)
Manufacturer	Analog Devices Inc./Maxim Integrated	Analog Devices Inc./Maxim Integrated
Memory Type	Non-Volatile SRAM	Non-Volatile SRAM
Memory Size	2Mbit	2Mbit
Memory Organization	256K x 8	256K x 8
Memory Interface	Parallel	Parallel
Access Time	85 ns	70 ns
Write Cycle Time	85 ns	70 ns
Supply Voltage	4.75V ~ 5.25V	4.75V ~ 5.25V
Operating Temperature	0°C ~ 70°C	0°C ~ 70°C
Package Type	32-DIP Module (0.600", 15.24mm)	32-DIP Module (0.600", 15.24mm)
Mounting Type	Through Hole	Through Hole
Product Status	Obsolete	Active
RoHS Status	RoHS non-compliant	ROHS3 Compliant
Packaging	Not specified	Tube

Engineering Selection Recommendations

The DS1249AB-70# is a direct functional substitute for the DS1249AB-85. Selection between these parts should be based on the following criteria:

Product Status: The DS1249AB-85 is obsolete, while the DS1249AB-70# is active. For new designs or ongoing production requiring NVSRAM 2Mbit parallel memory in 32-DIP packaging, the DS1249AB-70# is the appropriate choice.

Compliance Considerations: The DS1249AB-70# meets ROHS3 compliance requirements, whereas the DS1249AB-85 is RoHS non-compliant. Systems subject to RoHS regulations must use the DS1249AB-70#.

Timing Specifications: The DS1249AB-70# operates with 70 nanosecond access and write cycle times, compared to 85 nanoseconds for the DS1249AB-85. This faster timing is backward compatible with systems designed for the original part, as the substitute meets or exceeds performance requirements.

Availability: The DS1249AB-70# is currently in active production with higher inventory availability (1377 pieces) compared to the obsolete DS1249AB-85 (728 pieces).

Frequently Asked Questions (FAQ)

Q: Can the DS1249AB-70# directly replace the DS1249AB-85 in existing circuit boards?

A: Yes. The DS1249AB-70# is pin-compatible and functionally equivalent. Both parts use identical 32-DIP packaging with 0.600" (15.24mm) spacing, identical supply voltage requirements (4.75V ~ 5.25V), and identical operating temperature range (0°C ~ 70°C). The faster access time of the substitute does not create compatibility issues.

Q: What is the significance of the access time difference between 85 ns and 70 ns?

A: Access time defines the maximum delay from address input to valid data output. The DS1249AB-70# with 70 ns access time is faster than the original 85 ns specification. Systems designed for 85 ns operation will function correctly with the faster 70 ns substitute, as timing margins are maintained or improved.

Q: Are there any compliance differences between these parts?

A: Yes. The DS1249AB-70# is ROHS3 compliant, while the DS1249AB-85 is RoHS non-compliant. For applications subject to RoHS regulations, the DS1249AB-70# is required.

Q: What packaging formats are available for these parts?

A: Both parts are available in 32-DIP Module (0.600", 15.24mm) through-hole packages. The DS1249AB-70# is supplied in tube packaging, while the DS1249AB-85 packaging format is not specified.

Q: Is the DS1249AB-70# suitable for new product designs?

A: Yes. The DS1249AB-70# is classified as active product status, making it appropriate for new designs. The obsolete DS1249AB-85 should not be used in new designs.

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