DM74LS240WM Equivalent & Substitute Parts

Part Overview

The DM74LS240WM is a logic buffer IC with inverting functionality, featuring 2 elements with 4 bits per element and 3-state output capability. Manufactured by onsemi in a 20-SOIC surface mount package, this component operates within the 4.75V to 5.25V supply voltage range and is rated for 0°C to 70°C operating temperature. The product status is obsolete, making identification of functionally equivalent alternatives essential for ongoing design support and production continuity.

Key Parameters

Parameter	Value
Logic Type	Buffer, Inverting
Number of Elements	2
Number of Bits per Element	4
Output Type	3-State
Current - Output High, Low	15mA, 24mA
Voltage - Supply	4.75V ~ 5.25V
Operating Temperature	0°C ~ 70°C
Mounting Type	Surface Mount
Package / Case	20-SOIC
Series	74LS

Substitute Part Grouping Explanation

Substitution eligibility for the DM74LS240WM is determined by strict equivalence across the following parameters: logic type (Buffer, Inverting), number of elements (2), bits per element (4), output type (3-State), output current specifications (15mA high, 24mA low), supply voltage range (4.75V ~ 5.25V), operating temperature range (0°C ~ 70°C), and series classification (74LS).

Substitute parts are categorized into two groups:

Direct Substitutes (Package-Identical): Parts maintaining the 20-SOIC (0.295", 7.50mm Width) package specification. These provide pin-for-pin and footprint-for-footprint compatibility without PCB modification.

Similar Substitutes (Package-Variant): Parts utilizing the 20-SO (0.209", 5.30mm Width) package variant. These maintain electrical equivalence and pin compatibility but differ in package width, requiring PCB footprint adjustment.

Parameter Comparison

Parameter	DM74LS240WM (onsemi)	SN74LS240DW (TI)	SN74LS240DWR (TI)	SN74LS240NS (TI)	SN74LS240NSR (TI)
Logic Type	Buffer, Inverting	Buffer, Inverting	Buffer, Inverting	Buffer, Inverting	Buffer, Inverting
Number of Elements	2	2	2	2	2
Number of Bits per Element	4	4	4	4	4
Output Type	3-State	3-State	3-State	3-State	3-State
Current - Output High, Low	15mA, 24mA	15mA, 24mA	15mA, 24mA	15mA, 24mA	15mA, 24mA
Voltage - Supply	4.75V ~ 5.25V	4.75V ~ 5.25V	4.75V ~ 5.25V	4.75V ~ 5.25V	4.75V ~ 5.25V
Operating Temperature	0°C ~ 70°C	0°C ~ 70°C	0°C ~ 70°C	0°C ~ 70°C	0°C ~ 70°C
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Package / Case	20-SOIC (0.295", 7.50mm)	20-SOIC (0.295", 7.50mm)	20-SOIC (0.295", 7.50mm)	20-SOIC (0.209", 5.30mm)	20-SOIC (0.209", 5.30mm)
Series	74LS	74LS	74LS	74LS	74LS
Product Status	Obsolete	Last Time Buy	Active	Last Time Buy	Active
RoHS Status	Not specified	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

For applications requiring immediate component availability and long-term supply assurance, SN74LS240DWR is the primary selection. This Texas Instruments part maintains full electrical and mechanical equivalence to the DM74LS240WM, operates within identical parameter specifications, and carries Active product status with 3100 units in stock. ROHS3 compliance certification is included.

SN74LS240DW provides an alternative direct substitute with identical package geometry and electrical characteristics. This part carries Last Time Buy status, indicating limited future availability.

For designs where package width reduction is acceptable, SN74LS240NSR and SN74LS240NS offer electrical equivalence with a narrower 20-SO package (0.209" width versus 0.295"). SN74LS240NSR maintains Active status with 3460 units available and ROHS3 compliance. SN74LS240NS carries Last Time Buy status.

All substitute parts maintain the 74LS series classification, identical logic functionality, output current specifications, supply voltage range, and operating temperature range as the original DM74LS240WM.

Frequently Asked Questions (FAQ)

Q: Can SN74LS240DWR be used as a direct replacement for DM74LS240WM without PCB modification?

A: Yes. Both parts utilize the 20-SOIC package with 0.295" (7.50mm) width, providing identical pin spacing and footprint compatibility. No PCB layout changes are required.

Q: What is the difference between SN74LS240DW and SN74LS240DWR?

A: Both parts are electrically identical with the same 20-SOIC (0.295") package. The primary difference is packaging format: SN74LS240DW is supplied in Tube packaging, while SN74LS240DWR is supplied in Cut Tape and Digi-Reel format. SN74LS240DWR maintains Active product status with higher inventory availability.

Q: Can SN74LS240NS be used instead of SN74LS240DW?

A: Electrical substitution is valid; however, the package differs. SN74LS240NS uses a 20-SO package with 0.209" (5.30mm) width, compared to the 0.295" (7.50mm) width of the original DM74LS240WM. PCB footprint modification is required for this substitution.

Q: Are all substitute parts RoHS compliant?

A: Yes. All Texas Instruments substitute parts (SN74LS240DW, SN74LS240DWR, SN74LS240NS, SN74LS240NSR) carry ROHS3 compliance certification. The original DM74LS240WM RoHS status is not specified in the provided data.

Q: Which substitute part offers the best long-term availability?

A: SN74LS240DWR is recommended for long-term supply assurance. It maintains Active product status, has the highest inventory level (3100 units), and provides direct package compatibility with the original DM74LS240WM.

Q: Do all parts operate within the same temperature and voltage ranges?

A: Yes. All parts operate within 0°C to 70°C temperature range and 4.75V to 5.25V supply voltage range, with identical output current specifications (15mA high, 24mA low).

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