DM81LS97AN Equivalent & Substitute Parts

Part Overview

The DM81LS97AN is a non-inverting buffer logic integrated circuit manufactured by onsemi, designed for 5V TTL applications. This device features 1 element with 8 bits per element and is housed in a 20-pin DIP package. The part is classified as obsolete, making equivalent and substitute parts necessary for ongoing system maintenance, repairs, and legacy design support.

Substiute Parts

DM81LS97AN

onsemiIn Stock: 2228DM81LS97AN Datasheet

Current PartRFQ

SN74LS240N

onsemiIn Stock: 2008SN74LS240N Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the DM81LS97AN is constrained by the following critical parameters:

• Logic Function: Non-inverting buffer operation
• Package Type: 20-DIP form factor with 0.300" (7.62mm) pitch
• Supply Voltage Range: 4.75V ~ 5.25V compatibility
• Operating Temperature Range: 0°C ~ 70°C
• Series Compatibility: 74LS TTL logic family
• Mounting Method: Through-hole PCB assembly

The SN74LS240N shares the same package, voltage range, temperature range, and series classification. However, it differs in logic function (inverting vs. non-inverting), element configuration (2 elements vs. 1 element), and bits per element (4 vs. 8). These functional differences require circuit-level evaluation for substitution feasibility.

Parameter Comparison

Engineering Selection Recommendations

Both the DM81LS97AN and SN74LS240N are classified as obsolete products within the 74LS TTL logic family. Selection between these parts must account for functional differences:

The DM81LS97AN provides non-inverting buffer operation with a single 8-bit element and standard output configuration. The SN74LS240N provides inverting buffer operation with two 4-bit elements and 3-state output capability. These functional differences mean direct pin-for-pin substitution is not possible without circuit modification.

The SN74LS240N exhibits higher output high current (15mA vs. 5.2mA), which may affect circuit loading characteristics. Both parts operate within identical supply voltage and temperature ranges and use the same 20-DIP package footprint.

RoHS compliance status differs between the two parts, with the SN74LS240N explicitly marked as RoHS non-compliant. This distinction is relevant for applications subject to environmental or regulatory restrictions.

Frequently Asked Questions (FAQ)

Q: Can the SN74LS240N directly replace the DM81LS97AN?

A: No. While both parts share the same 20-DIP package, voltage range, and temperature range, they differ in logic function (inverting vs. non-inverting), element count, and output configuration. Direct substitution requires circuit-level analysis and potential redesign.

Q: What are the key differences between these parts?

A: The DM81LS97AN is a non-inverting buffer with 1 element of 8 bits. The SN74LS240N is an inverting buffer with 2 elements of 4 bits each and 3-state output capability. Output current specifications also differ (5.2mA vs. 15mA for high output).

Q: Are both parts compatible with the same PCB footprint?

A: Yes. Both parts use the 20-DIP (0.300", 7.62mm) package and are compatible with identical through-hole PCB layouts. However, functional differences prevent direct pin-for-pin substitution.

Q: What is the significance of the 3-state output on the SN74LS240N?

A: The 3-state output allows the part to be placed in a high-impedance state, enabling multiple devices to share a common bus. The DM81LS97AN does not have this capability.

Q: Are there RoHS compliance considerations?

A: The SN74LS240N is marked as RoHS non-compliant. If RoHS compliance is required for your application, this distinction must be evaluated against your regulatory requirements.

Q: What supply voltage range do these parts support?

A: Both parts operate within the 4.75V ~ 5.25V range, consistent with standard 5V TTL logic family specifications.