LM331N Voltage to Frequency Converter IC - Equivalent & Substitute Parts

Part Overview

The LM331N is a Voltage to Frequency Converter IC manufactured by Texas Instruments, designed for precision analog-to-digital conversion applications. Operating at a maximum frequency of 100 kHz with ±0.01% linearity, this component converts analog voltage signals into proportional frequency outputs. The LM331N is classified as obsolete, which necessitates identification of functionally equivalent alternatives for new designs and ongoing production requirements. The availability of active substitute parts ensures continuity in applications requiring this specific conversion functionality.

Substiute Parts

LM331N

Texas InstrumentsIn Stock: 10211LM331N Datasheet

Current PartRFQ

LM331N/NOPB

Texas InstrumentsIn Stock: 33761LM331N/NOPB Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the LM331N is determined by strict equivalence across the following critical parameters:

• Functional Type: Voltage to Frequency Converter
• Maximum Frequency: 100 kHz
• Linearity Specification: ±0.01%
• Temperature Coefficient: ±150 ppm/°C
• Package Configuration: 8-DIP (0.300", 7.62mm) / 8-PDIP
• Mounting Technology: Through Hole
• Base Product Number: LM331

The LM331N/NOPB qualifies as a direct substitute based on identical electrical specifications and package geometry. The primary distinction lies in product status and compliance certifications, which affect procurement and long-term availability.

Parameter Comparison

Engineering Selection Recommendations

The LM331N/NOPB is the direct functional equivalent of the LM331N. Both parts share identical electrical characteristics, frequency response, linearity, and thermal performance specifications. The LM331N/NOPB is classified as an active product with ROHS3 compliance, whereas the original LM331N is obsolete and RoHS non-compliant.

For new designs and production applications, the LM331N/NOPB is the appropriate selection due to its active product status and regulatory compliance. The LM331N remains available in existing inventory for legacy system maintenance and repair applications where RoHS compliance is not a requirement.

Both parts utilize identical 8-DIP through-hole packaging, ensuring direct pin-for-pin compatibility without circuit board modifications.

Frequently Asked Questions (FAQ)

Q: Can the LM331N/NOPB be used as a direct replacement for the LM331N?

A: Yes. The LM331N/NOPB is electrically and mechanically identical to the LM331N. Both parts feature 100 kHz maximum frequency, ±0.01% linearity, and ±150 ppm/°C temperature coefficient. Pin configuration and 8-DIP package dimensions are identical, enabling direct substitution without circuit modifications.

Q: What is the difference between LM331N and LM331N/NOPB?

A: The primary differences are product status and compliance certifications. The LM331N is obsolete and RoHS non-compliant. The LM331N/NOPB is an active product with ROHS3 compliance. Electrical performance and package specifications are identical.

Q: Why is the LM331N classified as obsolete?

A: The LM331N has been superseded by the LM331N/NOPB variant, which incorporates RoHS3 compliance and maintains active production status. The original LM331N remains available through existing inventory channels.

Q: Are there any package or mounting differences between these parts?

A: No. Both the LM331N and LM331N/NOPB use 8-DIP (0.300", 7.62mm) through-hole packaging. The LM331N/NOPB is supplied in tube packaging, while the original LM331N packaging specification is not detailed. Pin configuration and board-level compatibility are identical.

Q: Which part should be selected for new production designs?

A: The LM331N/NOPB should be selected for new designs. It is an active product with current manufacturing support and ROHS3 compliance, ensuring long-term availability and regulatory alignment.