DM74LS393N Binary Counter IC Equivalent & Substitute Parts

Part Overview

The DM74LS393N is a dual 4-bit binary counter IC manufactured by onsemi, designed for digital counting and frequency division applications. This component features two independent 4-bit counters with asynchronous reset capability, operating at a maximum count rate of 25 MHz. The part is classified as obsolete, making equivalent substitutes necessary for new designs and production continuity. The DM74LS393N operates within the standard TTL logic supply voltage range of 4.75 V to 5.25 V and is housed in a 14-pin DIP package suitable for through-hole mounting.

Substiute Parts

DM74LS393N

onsemiIn Stock: 1510DM74LS393N Datasheet

Current PartRFQ

SN74LS393N

Texas InstrumentsIn Stock: 3376SN74LS393N Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the DM74LS393N is based on functional equivalence within the 74LS logic family. The SN74LS393N from Texas Instruments qualifies as a direct substitute based on the following criteria:

Critical Matching Parameters:

• Logic Type: Binary Counter (identical)
• Number of Elements: 2 (identical)
• Number of Bits per Element: 4 (identical)
• Direction: Up (identical)
• Reset Type: Asynchronous (identical)
• Trigger Type: Negative Edge (identical)
• Voltage - Supply: 4.75 V ~ 5.25 V (identical)
• Operating Temperature: 0°C ~ 70°C (identical)
• Package / Case: 14-DIP (0.300", 7.62mm) (identical)
• Mounting Type: Through Hole (identical)

Both parts share the same base product number (74LS393) and are pin-compatible with identical functional behavior. The substitute maintains all electrical and mechanical specifications required for direct replacement.

Parameter Comparison

Engineering Selection Recommendations

The SN74LS393N from Texas Instruments is the direct functional equivalent for the obsolete DM74LS393N. Selection of the Texas Instruments part offers the following advantages:

Product Status: The SN74LS393N maintains active production status, ensuring long-term availability and supply chain continuity compared to the obsolete onsemi part.

Compliance: The SN74LS393N is ROHS3 compliant, meeting current environmental and regulatory requirements. The original DM74LS393N is RoHS non-compliant, which may present procurement and regulatory challenges in modern manufacturing environments.

Performance: The SN74LS393N operates at a maximum count rate of 35 MHz, exceeding the 25 MHz specification of the DM74LS393N. This higher performance rating provides additional operational margin without compromising compatibility.

Pin and Package Compatibility: Both parts are housed in identical 14-DIP packages with through-hole mounting, ensuring direct PCB compatibility without layout modifications.

For applications requiring the DM74LS393N, the SN74LS393N provides equivalent functionality with improved product status, regulatory compliance, and performance characteristics.

Frequently Asked Questions (FAQ)

Q: Is the SN74LS393N a direct pin-for-pin replacement for the DM74LS393N?

A: Yes. Both parts are housed in 14-DIP packages with identical pinouts and functional behavior. No PCB modifications are required for substitution.

Q: What are the key functional parameters that determine substitution compatibility?

A: Substitution is based on matching logic type (Binary Counter), element count (2), bit width (4 bits per element), reset type (Asynchronous), trigger type (Negative Edge), supply voltage range (4.75 V ~ 5.25 V), and package type (14-DIP). The SN74LS393N matches all these parameters.

Q: Does the higher count rate of the SN74LS393N (35 MHz vs. 25 MHz) affect compatibility?

A: No. The higher count rate of the SN74LS393N represents improved performance and does not compromise compatibility. Applications designed for the 25 MHz DM74LS393N will operate correctly with the 35 MHz SN74LS393N.

Q: What is the significance of the RoHS compliance difference?

A: The SN74LS393N is ROHS3 compliant, meeting current environmental regulations. The DM74LS393N is RoHS non-compliant. For new designs and production environments subject to RoHS requirements, the SN74LS393N is the appropriate choice.

Q: Can the SN74LS393N be used in existing designs originally specified for the DM74LS393N?

A: Yes. The SN74LS393N is functionally equivalent and pin-compatible. It can be directly substituted in existing designs without circuit modifications or re-qualification, provided the application does not depend on the specific manufacturer characteristics of the original part.

Q: Are there any package or mounting considerations when substituting these parts?

A: Both parts use identical 14-DIP through-hole packages. No changes to PCB footprints, mounting methods, or assembly procedures are required.