DM74LS74AM Equivalent & Substitute Parts

Part Overview

The DM74LS74AM is a dual D-type flip-flop logic integrated circuit manufactured by onsemi in 14-SOIC surface mount packaging. This component functions as a 2-element D-type flip-flop with complementary outputs, set/preset and reset capabilities, and positive edge triggering. The part is classified as obsolete, making equivalent substitutes necessary for new designs and ongoing production requirements.

Key Parameters

Parameter	Value
Manufacturer Part Number	DM74LS74AM
Manufacturer	onsemi
Category	Logic
Type	D-Type Flip-Flop
Number of Elements	2
Number of Bits per Element	1
Output Type	Complementary
Function	Set(Preset) and Reset
Trigger Type	Positive Edge
Clock Frequency	20 MHz
Voltage - Supply	4.75V ~ 5.25V
Current - Output High, Low	400µA, 8mA
Operating Temperature	0°C ~ 70°C (TA)
Package / Case	14-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
Product Status	Obsolete
RoHS Status	RoHS non-compliant

Substitute Part Grouping Explanation

Substitution eligibility for the DM74LS74AM is determined by the following critical parameters:

Type: D-Type flip-flop with 2 elements, 1 bit per element
Output Type: Complementary outputs
Function: Set(Preset) and Reset capability
Trigger Type: Positive edge triggering
Voltage Supply Range: 4.75V ~ 5.25V
Current Output Specifications: 400µA (high), 8mA (low)
Operating Temperature Range: 0°C ~ 70°C
Package: 14-SOIC surface mount

All substitute parts listed maintain these core electrical and functional parameters. Variations in clock frequency, propagation delay, and RoHS compliance status do not disqualify substitution when the primary functional and electrical specifications align.

Parameter Comparison

Parameter	DM74LS74AM (Main)	SN74LS74AD	SN74LS74ADE4	SN74LS74ADR	SN74LS74ANSR
Manufacturer	onsemi	Texas Instruments	Texas Instruments	Texas Instruments	Texas Instruments
Type	D-Type	D-Type	D-Type	D-Type	D-Type
Number of Elements	2	2	2	2	2
Output Type	Complementary	Complementary	Complementary	Complementary	Complementary
Function	Set(Preset) and Reset	Set(Preset) and Reset	Set(Preset) and Reset	Set(Preset) and Reset	Set(Preset) and Reset
Trigger Type	Positive Edge	Positive Edge	Positive Edge	Positive Edge	Positive Edge
Clock Frequency	20 MHz	33 MHz	33 MHz	33 MHz	33 MHz
Voltage - Supply	4.75V ~ 5.25V	4.75V ~ 5.25V	4.75V ~ 5.25V	4.75V ~ 5.25V	4.75V ~ 5.25V
Current - Output High, Low	400µA, 8mA	400µA, 8mA	400µA, 8mA	400µA, 8mA	400µA, 8mA
Operating Temperature	0°C ~ 70°C	0°C ~ 70°C	0°C ~ 70°C	0°C ~ 70°C	0°C ~ 70°C
Package / Case	14-SOIC (0.154", 3.90mm)	14-SOIC (0.154", 3.90mm)	14-SOIC (0.154", 3.90mm)	14-SOIC (0.154", 3.90mm)	14-SOIC (0.209", 5.30mm)
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Product Status	Obsolete	Discontinued at DiGi Electronics	Discontinued at DiGi Electronics	Active	Active
RoHS Status	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

SN74LS74ADR is the primary recommended substitute. This Texas Instruments part maintains all functional and electrical specifications of the DM74LS74AM while offering active product status and ROHS3 compliance. The higher clock frequency (33 MHz vs. 20 MHz) provides additional performance margin without affecting backward compatibility. This part is currently in active production with substantial inventory availability.

SN74LS74ANSR serves as an alternative substitute with identical electrical performance and active status. The primary distinction is package width (0.209" vs. 0.154"), which may require PCB layout verification for space-constrained applications. This part is also ROHS3 compliant and actively produced.

SN74LS74AD and SN74LS74ADE4 are functionally equivalent but carry discontinued status at DiGi Electronics, limiting long-term availability for production applications.

Frequently Asked Questions (FAQ)

Q: Can SN74LS74ADR directly replace DM74LS74AM in existing designs?

A: Yes. The SN74LS74ADR maintains identical functional specifications, electrical parameters, and 14-SOIC packaging (0.154", 3.90mm width). No circuit modifications are required.

Q: What is the significance of the higher clock frequency in substitute parts?

A: The substitute parts operate at 33 MHz versus the original 20 MHz specification. This represents improved performance capability and does not create compatibility issues in applications designed for the original 20 MHz part.

Q: Does the package width difference between SN74LS74ADR and SN74LS74ANSR affect substitution?

A: Package width differs (0.154" vs. 0.209"), but both use 14-SOIC surface mount configuration. PCB footprint compatibility must be verified before selection. SN74LS74ADR maintains the original width specification.

Q: Why is RoHS compliance important for this substitution?

A: The original DM74LS74AM is RoHS non-compliant. All Texas Instruments substitutes are ROHS3 compliant, meeting current environmental and regulatory requirements for new designs and production applications.

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

A: SN74LS74ADR carries active product status with the highest inventory levels (2902 Pcs), ensuring sustained availability for ongoing production requirements.

Q: Are propagation delay specifications critical for substitution?

A: The substitute parts specify 40ns maximum propagation delay at 5V with 15pF load. This parameter was not provided for the original DM74LS74AM. Both parts operate within the 74LS logic family timing specifications and are functionally compatible.

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