NE521DG Equivalent & Substitute Parts

Part Overview

The NE521DG is a differential comparator IC manufactured by onsemi, housed in a 14-SOIC surface mount package. This device features two differential comparator elements with TTL output configuration and operates across a ±4.75V to ±5.25V supply voltage range. The NE521DG is classified as obsolete, making identification of functionally equivalent substitute components essential for ongoing design support and production continuity.

Substiute Parts

NE521DG

onsemiIn Stock: 2937NE521DG Datasheet

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LM361M/NOPB

Texas InstrumentsIn Stock: 1599LM361M/NOPB Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the NE521DG is determined by the following critical parameters:

• Package Compatibility: Both the main part and substitute must use 14-SOIC surface mount packaging with identical 0.154" (3.90mm) width to ensure PCB footprint compatibility without layout modifications.
• Functional Architecture: Differential comparator configuration with two independent elements is required to maintain circuit functionality.
• Output Configuration: TTL or complementary TTL output types are acceptable, as both provide digital logic-level outputs compatible with standard TTL/CMOS logic families.
• Supply Voltage Range: The substitute must operate within or encompass the ±4.75V to ±5.25V supply range of the original part.
• Electrical Performance: Input offset voltage, input bias current, quiescent current, and propagation delay specifications must meet or exceed the performance envelope of the NE521DG to ensure functional equivalence in signal conditioning and timing-critical applications.

Parameter Comparison

Engineering Selection Recommendations

The LM361M/NOPB from Texas Instruments is a direct functional substitute for the obsolete NE521DG. Both devices share identical 14-SOIC packaging, dual differential comparator architecture, and compatible operating temperature ranges. The LM361M/NOPB offers superior electrical performance with lower input offset voltage (5mV vs. 7.5mV), reduced input bias current (10µA vs. 20µA), and lower quiescent current consumption (5-20mA vs. 35mA). The LM361M/NOPB supports an extended supply voltage range (±5V ~ 15V), providing greater design flexibility for applications requiring higher supply voltages. The complementary TTL output configuration of the LM361M/NOPB is fully compatible with standard TTL logic interfaces. As an active product from a major manufacturer with ROHS3 compliance and REACH unaffected status, the LM361M/NOPB ensures long-term availability and regulatory compliance for new designs and production continuity.

Frequently Asked Questions (FAQ)

Q: Can the LM361M/NOPB directly replace the NE521DG without PCB modifications?

A: Yes. Both devices use identical 14-SOIC packaging with 0.154" (3.90mm) width, enabling direct pin-compatible substitution without PCB layout changes.

Q: What are the key electrical differences between these parts?

A: The LM361M/NOPB provides improved performance specifications: lower input offset voltage (5mV vs. 7.5mV), reduced input bias current (10µA vs. 20µA), and lower quiescent current (5-20mA vs. 35mA). The LM361M/NOPB also supports a wider supply voltage range (±5V ~ 15V vs. ±4.75V ~ 5.25V).

Q: Is the complementary TTL output of the LM361M/NOPB compatible with circuits designed for the NE521DG TTL output?

A: Yes. Complementary TTL output is a superset of standard TTL output, providing both true and inverted logic signals. Circuits designed for standard TTL output will function correctly with complementary TTL output by using the appropriate output signal.

Q: Why is the NE521DG classified as obsolete?

A: The NE521DG has been discontinued by onsemi. The LM361M/NOPB from Texas Instruments is an active product offering equivalent functionality with improved performance and long-term availability.

Q: Are there any compliance or regulatory considerations when substituting the LM361M/NOPB for the NE521DG?

A: Both devices are REACH unaffected and classified under the same HTSUS commodity code. The LM361M/NOPB carries ROHS3 compliance, ensuring regulatory alignment with current environmental standards.

Q: What is the propagation delay difference, and does it affect circuit timing?

A: The LM361M/NOPB has a maximum propagation delay of 20ns compared to 12ns for the NE521DG. Applications with strict timing requirements should verify that the 8ns difference does not exceed system timing margins.