ISD2540S Voice Record/Playback IC Equivalent & Substitute Parts

Part Overview

The ISD2540S is a ChipCorder® voice record/playback interface IC manufactured by Nuvoton Technology Corporation, designed for multiple message applications with 40-second recording and playback duration. The device features pushbutton control, automatic gain control, and operates across a 4.5V to 6.5V supply range in a 28-SOIC surface mount package.

The ISD2540S is classified as obsolete. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure component availability, and support ongoing production or maintenance requirements for systems utilizing this interface IC.

Substiute Parts

ISD2540S

Nuvoton Technology CorporationIn Stock: 5419ISD2540S Datasheet

Current PartRFQ

ISD1740SY

Nuvoton Technology CorporationIn Stock: 2311ISD1740SY Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the ISD2540S is determined by compatibility across the following critical parameters:

Package Compatibility: Both the main part and substitute must use the 28-SOIC surface mount package to ensure direct PCB footprint compatibility without layout modifications.

Functional Compatibility: The substitute must support voice record/playback functionality with pushbutton interface control and automatic gain control features.

Electrical Compatibility: The substitute must operate within overlapping or compatible supply voltage ranges and support equivalent input/output signal types (analog microphone input, speaker output).

Series Continuity: The substitute is sourced from the same ChipCorder® product family, ensuring design methodology and application support consistency.

The ISD1740SY meets these substitution criteria as a manufacturer-recommended equivalent within the ChipCorder® series, sharing the same 28-SOIC package, pushbutton interface capability, and core voice processing functionality.

Parameter Comparison

Engineering Selection Recommendations

For Active Production and New Designs: The ISD1740SY is the recommended substitute for the obsolete ISD2540S. The ISD1740SY maintains active product status with ROHS3 compliance, ensuring long-term component availability and regulatory alignment with current manufacturing standards. Both devices share identical 28-SOIC packaging and core pushbutton interface functionality.

For Legacy System Maintenance: The ISD1740SY provides functional equivalence for repair and maintenance applications. The extended duration range (26–80 seconds versus fixed 40 seconds) and expanded sampling frequency capability (4–12kHz versus fixed 6.4kHz) offer design flexibility without requiring PCB modifications.

Supply Voltage Consideration: The ISD1740SY operates across 2.4V to 5.5V, which overlaps with the ISD2540S range of 4.5V to 6.5V within the 4.5V to 5.5V window. Designs operating at the upper end of the ISD2540S range (above 5.5V) require supply voltage adjustment or regulation to ensure ISD1740SY compatibility.

Compliance Status: The transition from RoHS non-compliant (ISD2540S) to ROHS3 compliant (ISD1740SY) aligns with current environmental and regulatory requirements for component procurement and manufacturing.

Frequently Asked Questions (FAQ)

Q: Can the ISD1740SY directly replace the ISD2540S without PCB modifications?

A: Yes. Both devices use the 28-SOIC surface mount package with identical pin spacing and footprint dimensions (0.295", 7.50mm width). Direct PCB substitution is possible without layout changes.

Q: What are the key functional differences between ISD2540S and ISD1740SY?

A: The ISD1740SY adds SPI interface capability alongside pushbutton control, extends recording duration to 26–80 seconds (versus fixed 40 seconds), provides adjustable sampling frequency (4–12kHz versus fixed 6.4kHz), and includes volume control in addition to automatic gain control. The ISD1740SY also supports analog speaker output in addition to PWM output.

Q: Is the ISD1740SY suitable for designs currently using ISD2540S?

A: The ISD1740SY is suitable for designs requiring equivalent voice record/playback functionality with pushbutton interface. Designs must accommodate the reduced upper supply voltage limit (5.5V maximum for ISD1740SY versus 6.5V for ISD2540S) and the increased moisture sensitivity level (MSL 3 versus MSL 1).

Q: Why is the ISD2540S classified as obsolete?

A: The ISD2540S is obsolete due to product lifecycle discontinuation by the manufacturer. The ISD1740SY represents the active equivalent within the ChipCorder® product family, offering enhanced functionality and current compliance certifications.

Q: Are there any packaging or storage differences between these parts?

A: The ISD2540S has unlimited moisture sensitivity (MSL 1), while the ISD1740SY requires controlled storage conditions (MSL 3, 168 hours maximum exposure at 60% relative humidity and 30°C). The ISD1740SY is supplied in tube packaging, requiring appropriate moisture control during storage and handling.

Q: What compliance certifications apply to each part?

A: The ISD2540S is RoHS non-compliant. The ISD1740SY is ROHS3 compliant. Both parts are REACH unaffected and classified under ECCN EAR99 and HTSUS 8542.39.0001.