AS4C64M8SA-7TCN SDRAM Memory IC Equivalent & Substitute Parts

Part Overview

The AS4C64M8SA-7TCN is a 512Mbit SDRAM memory IC manufactured by Alliance Memory, Inc., featuring parallel interface architecture with 64M x 8 organization and 133 MHz clock frequency. This component operates at 3V to 3.6V supply voltage with 5.4 ns access time in a 54-TSOP II surface mount package. The part is classified as obsolete, necessitating identification of functionally equivalent alternatives for ongoing system support and new designs requiring compatible memory solutions.

Key Parameters

Parameter	Value
Memory Type	Volatile DRAM
Memory Format	SDRAM
Memory Size	512Mbit
Memory Organization	64M x 8
Memory Interface	Parallel
Clock Frequency	133 MHz
Access Time	5.4 ns
Voltage Supply	3V to 3.6V
Operating Temperature	0°C to 70°C (TA)
Package Type	54-TSOP II (0.400", 10.16mm Width)
Mounting Type	Surface Mount
RoHS Status	ROHS3 Compliant
MSL Rating	3 (168 Hours)

Substitute Part Grouping Explanation

Substitution eligibility for the AS4C64M8SA-7TCN is determined by strict equivalence across the following critical parameters:

Memory capacity: 512Mbit with 64M x 8 organization
Interface type: Parallel SDRAM architecture
Access time: 5.4 ns maximum
Supply voltage: 3V to 3.6V operating range
Package: 54-TSOP II form factor
Mounting: Surface mount technology

Clock frequency tolerance permits substitution of parts operating at 133 MHz or higher (143 MHz, 166 MHz), as faster-rated devices maintain backward compatibility with lower-frequency system requirements. Operating temperature range variations are acceptable when the substitute part's range encompasses or exceeds the original specification. RoHS compliance status and packaging format (tube, tray, tape & reel) do not affect functional substitutability but may impact procurement and assembly workflows.

Parameter Comparison

Part Number	Manufacturer	Memory Size	Organization	Clock Frequency (MHz)	Access Time (ns)	Voltage (V)	Temp Range (°C)	Package	Product Status	RoHS Status
AS4C64M8SA-7TCN	Alliance Memory	512Mbit	64M x 8	133	5.4	3.0–3.6	0 to 70	54-TSOP II	Obsolete	ROHS3
MT48LC64M8A2P-75:C	Micron Technology	512Mbit	64M x 8	133	5.4	3.0–3.6	0 to 70	54-TSOP II	Obsolete	ROHS3
MT48LC64M8A2TG-75:C	Alliance Memory	512Mbit	64M x 8	133	5.4	3.0–3.6	0 to 70	54-TSOP II	Obsolete	Non-compliant
MT48LC64M8A2TG-75:IT:C	Alliance Memory	512Mbit	64M x 8	133	5.4	3.0–3.6	-40 to 85	54-TSOP II	Active	Non-compliant
IS42S86400F-6TL	ISSI	512Mbit	64M x 8	166	5.4	3.0–3.6	0 to 70	54-TSOP II	Active	ROHS3
IS42S86400F-6TLI	ISSI	512Mbit	64M x 8	166	5.4	3.0–3.6	-40 to 85	54-TSOP II	Active	ROHS3
IS42S86400F-7TL	ISSI	512Mbit	64M x 8	143	5.4	3.0–3.6	0 to 70	54-TSOP II	Active	ROHS3
IS42S86400F-7TLI	ISSI	512Mbit	64M x 8	143	5.4	3.0–3.6	-40 to 85	54-TSOP II	Active	ROHS3
IS42S86400F-7TLI-TR	ISSI	512Mbit	64M x 8	143	5.4	3.0–3.6	-40 to 85	54-TSOP II	Active	ROHS3

Engineering Selection Recommendations

Primary Recommendation: IS42S86400F-7TLI or IS42S86400F-7TLI-TR

These ISSI parts offer active product status with ROHS3 compliance, ensuring long-term availability and regulatory alignment. The 143 MHz clock frequency exceeds the original 133 MHz specification while maintaining full backward compatibility. Extended temperature range (-40°C to 85°C) provides operational flexibility beyond the original 0°C to 70°C window. Both variants are functionally identical; selection between tray (IS42S86400F-7TLI) and tape & reel (IS42S86400F-7TLI-TR) packaging depends on assembly volume and handling requirements.

Secondary Recommendation: IS42S86400F-6TL or IS42S86400F-6TLI

These higher-frequency variants (166 MHz) provide additional performance margin. The IS42S86400F-6TLI variant includes extended temperature range and is recommended for applications requiring industrial-grade thermal specifications.

Alternative: MT48LC64M8A2TG-75:IT:C

This Alliance Memory part maintains active product status with extended temperature range (-40°C to 85°C). However, RoHS non-compliance may restrict use in regulated applications. This option is suitable for legacy system maintenance where RoHS requirements do not apply.

Not Recommended: MT48LC64M8A2P-75:C and MT48LC64M8A2TG-75:C

Both parts carry obsolete product status, limiting long-term procurement viability. These should be considered only for immediate replacement needs where inventory is available.

Frequently Asked Questions (FAQ)

Q: Can I substitute IS42S86400F-6TL for AS4C64M8SA-7TCN in my existing design?

A: Yes. The IS42S86400F-6TL meets all critical substitution parameters: identical 512Mbit capacity, 64M x 8 organization, 5.4 ns access time, 3V to 3.6V supply voltage, and 54-TSOP II package. The 166 MHz clock frequency exceeds the original 133 MHz requirement and is fully backward compatible. Verify your system controller supports the higher frequency if timing-critical operations are present.

Q: What is the difference between IS42S86400F-7TLI and IS42S86400F-7TLI-TR?

A: Both parts are functionally identical with 143 MHz clock frequency, 512Mbit capacity, and extended temperature range (-40°C to 85°C). The primary difference is packaging format: IS42S86400F-7TLI is supplied in trays for manual handling or small-volume assembly, while IS42S86400F-7TLI-TR is supplied in tape & reel format for automated pick-and-place assembly. Select based on your manufacturing process requirements.

Q: Why is MT48LC64M8A2TG-75:IT:C marked as active while the original AS4C64M8SA-7TCN is obsolete?

A: Product status reflects manufacturer support and production continuity. MT48LC64M8A2TG-75:IT:C remains in active production by Alliance Memory with extended temperature range support, making it suitable for new designs and ongoing system support. The original part has been discontinued.

Q: Are there any compliance differences I should consider?

A: Yes. IS42S86400F series parts carry ROHS3 compliance, meeting current environmental regulations. MT48LC64M8A2TG-75:IT:C is RoHS non-compliant. If your application or market requires RoHS certification, select from the ISSI IS42S86400F series or Micron MT48LC64M8A2P-75:C.

Q: Can I use a 166 MHz part in a system designed for 133 MHz?

A: Yes. Higher clock frequency ratings are backward compatible with lower-frequency system requirements. The IS42S86400F-6TL and IS42S86400F-6TLI (166 MHz variants) will operate correctly in 133 MHz systems. No design modifications are required.

Q: What temperature range should I specify for new designs?

A: For maximum flexibility and industrial applications, specify parts with -40°C to 85°C operating range: IS42S86400F-6TLI, IS42S86400F-7TLI, IS42S86400F-7TLI-TR, or MT48LC64M8A2TG-75:IT:C. For consumer or standard commercial applications, 0°C to 70°C range parts are acceptable.

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