DM74ALS521WMX Equivalent & Substitute Parts

Part Overview

The DM74ALS521WMX is an 8-bit magnitude comparator with active low output (A=B function) manufactured by onsemi in a 20-SOIC surface mount package. This component is classified as obsolete, making substitute parts necessary for new designs and ongoing production requirements. The part operates within the 4.5V to 5.5V supply voltage range and is suitable for digital logic applications requiring identity comparison functionality.

Key Parameters

Parameter	Value
Manufacturer Part Number	DM74ALS521WMX
Manufacturer	onsemi
Series	74ALS
Type	Identity Comparator
Number of Bits	8
Output Type	Active Low
Output Function	A=B
Voltage - Supply	4.5V ~ 5.5V
Current - Output High	2.6mA
Current - Output Low	24mA
Max Propagation Delay	20ns @ 5V, 50pF
Operating Temperature	0°C ~ 70°C
Package / Case	20-SOIC (0.295", 7.50mm Width)
Mounting Type	Surface Mount
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution for the DM74ALS521WMX is determined by strict equivalence across the following critical parameters:

Series and Base Product Number: 74ALS521 (ensures functional and pin compatibility)
Number of Bits: 8-bit configuration
Output Type and Function: Active Low output with A=B comparison function
Voltage Supply Range: 4.5V ~ 5.5V
Output Electrical Characteristics: 2.6mA high, 24mA low
Propagation Delay: 20ns @ 5V, 50pF
Operating Temperature Range: 0°C ~ 70°C
Package / Case: 20-SOIC form factor
Mounting Type: Surface Mount

All substitute parts listed maintain identical electrical performance and mechanical compatibility with the original DM74ALS521WMX.

Parameter Comparison

Parameter	DM74ALS521WMX (onsemi)	SN74ALS521DW (TI)	SN74ALS521DWR (TI)
Series	74ALS	74ALS	74ALS
Type	Identity Comparator	Identity Comparator	Identity Comparator
Number of Bits	8	8	8
Output	Active Low	Active Low	Active Low
Output Function	A=B	A=B	A=B
Voltage - Supply	4.5V ~ 5.5V	4.5V ~ 5.5V	4.5V ~ 5.5V
Current - Output High, Low	2.6mA, 24mA	2.6mA, 24mA	2.6mA, 24mA
Max Propagation Delay @ V, Max CL	20ns @ 5V, 50pF	20ns @ 5V, 50pF	20ns @ 5V, 50pF
Operating Temperature	0°C ~ 70°C	0°C ~ 70°C	0°C ~ 70°C
Package / Case	20-SOIC (0.295", 7.50mm Width)	20-SOIC (0.295", 7.50mm Width)	20-SOIC (0.295", 7.50mm Width)
Mounting Type	Surface Mount	Surface Mount	Surface Mount
Product Status	Obsolete	Last Time Buy	Active
RoHS Status	Not specified	ROHS3 Compliant	ROHS3 Compliant
Packaging	Not specified	Tube	Tape & Reel (TR)

Engineering Selection Recommendations

SN74ALS521DWR (Texas Instruments) is the primary substitute for new designs and production. This part carries Active product status, ensuring long-term availability and supply chain stability. It is ROHS3 compliant and supplied in Tape & Reel packaging, which is standard for automated assembly processes.

SN74ALS521DW (Texas Instruments) is an alternative substitute with Last Time Buy status. This part is electrically and mechanically equivalent but is supplied in Tube packaging. Selection of this part should be limited to applications where existing inventory management practices accommodate the Last Time Buy designation.

Both Texas Instruments substitutes provide identical electrical performance and mechanical compatibility with the obsolete DM74ALS521WMX, with the distinction that SN74ALS521DWR offers superior long-term availability.

Frequently Asked Questions (FAQ)

Q: Can SN74ALS521DW and SN74ALS521DWR be used interchangeably with DM74ALS521WMX?

A: Yes. Both parts are direct functional and pin-compatible substitutes. They share identical electrical specifications, including 8-bit comparison capability, active low output, 4.5V to 5.5V supply voltage, and 20-SOIC package configuration. The difference between the two Texas Instruments parts is packaging format (Tube vs. Tape & Reel) and product status.

Q: What is the difference between SN74ALS521DW and SN74ALS521DWR?

A: Both parts are electrically identical. The primary differences are packaging and product status. SN74ALS521DW is supplied in Tube packaging with Last Time Buy status. SN74ALS521DWR is supplied in Tape & Reel packaging with Active product status, making it the preferred choice for ongoing production.

Q: Why is the DM74ALS521WMX obsolete?

A: The DM74ALS521WMX is classified as obsolete by onsemi. Texas Instruments continues to manufacture equivalent 74ALS521 comparators, making substitution straightforward for design transitions and production continuity.

Q: Are there any compliance differences between the substitute parts?

A: Both Texas Instruments substitutes are ROHS3 compliant. The original DM74ALS521WMX compliance status is not specified in available documentation. All three parts share identical REACH and ECCN classifications (REACH Unaffected, EAR99).

Q: Can these parts be used in new PCB designs?

A: Yes. SN74ALS521DWR is recommended for new designs due to its Active product status and standard Tape & Reel packaging. The 20-SOIC package is widely supported by PCB design tools and assembly equipment.

Q: What is the moisture sensitivity level for these parts?

A: All three parts carry MSL 1 (Unlimited) rating, indicating no moisture sensitivity restrictions for storage or handling.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message