PUI Audio X-21 Piezo Buzzer - Equivalent & Substitute Parts

Part Overview

The PUI Audio X-21 is a panel-mounted piezo buzzer with internally driven indicator circuitry, rated for 32V DC operation at 2.8kHz. This component is classified as obsolete, making identification of compatible substitute parts essential for ongoing system maintenance and new design implementations. The X-21 serves as an audible indicator in applications requiring reliable piezo-based signaling without external driver circuitry.

Substiute Parts

X-21

PUI Audio, Inc.In Stock: 782X-21 Datasheet

Current PartRFQ

X-4035-P-FP32-R

PUI Audio, Inc.In Stock: 1212X-4035-P-FP32-R Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

The X-4035-P-FP32-R qualifies as a direct substitute for the X-21 based on the following alignment of critical parameters:

• Manufacturer: Both parts are manufactured by PUI Audio, Inc., ensuring design consistency and quality standards
• Series: Both belong to the X series product line
• Driver Circuitry: Both feature internally driven indicator circuitry, eliminating the need for external driver modifications
• Input Type: Both operate on DC input
• Voltage - Rated: Both are rated for 32V operation
• Frequency: Both operate at 2.8kHz
• Technology: Both utilize piezo technology
• Mounting Type: Both are panel-mounted configurations

The X-4035-P-FP32-R provides enhanced specifications including defined voltage range (3–32V), measurable current draw (21mA), quantified sound pressure level (95dB @ 32V, 10cm), operating temperature range (-30°C to 80°C), and improved RoHS3 compliance status.

Parameter Comparison

Engineering Selection Recommendations

The X-4035-P-FP32-R is the appropriate substitute for the obsolete X-21 based on the following engineering criteria:

Product Status: The X-21 is classified as obsolete, making the active-status X-4035-P-FP32-R the necessary replacement for continued supply chain viability and long-term component availability.

Compliance Status: The X-4035-P-FP32-R achieves RoHS3 compliance, whereas the X-21 is RoHS non-compliant. For applications subject to RoHS directives or environmental regulations, the X-4035-P-FP32-R satisfies current compliance requirements. Both parts maintain REACH Unaffected status.

Functional Equivalence: The X-4035-P-FP32-R maintains all critical functional parameters of the X-21, including 32V rated voltage, 2.8kHz frequency, internally driven indicator circuitry, and panel mount configuration. The substitute provides additional documented specifications (voltage range, current draw, SPL, operating temperature) that were not specified for the original part.

Supply Chain: The X-4035-P-FP32-R has 1,132 units in stock compared to the X-21's 683 units, providing improved availability for production and maintenance applications.

Frequently Asked Questions (FAQ)

Q: Can the X-4035-P-FP32-R directly replace the X-21 in existing designs?

A: Yes. Both parts share identical core specifications: 32V rated voltage, 2.8kHz frequency, internally driven indicator circuitry, piezo technology, and panel mount configuration. The X-4035-P-FP32-R is designed as a direct substitute within the PUI Audio X series product line.

Q: What are the key differences between these parts?

A: The X-4035-P-FP32-R provides fully specified parameters including voltage range (3–32V), current draw (21mA), sound pressure level (95dB @ 32V, 10cm), and operating temperature range (-30°C to 80°C). The X-21 specifications for these parameters were not documented. Additionally, the X-4035-P-FP32-R achieves RoHS3 compliance while the X-21 is RoHS non-compliant.

Q: Are there termination differences between the X-21 and X-4035-P-FP32-R?

A: The X-4035-P-FP32-R specifies screw terminal and quick connect tab (0.187" / 4.75mm) termination. The X-21 termination type was not documented. Physical installation should be verified against your specific panel mount configuration.

Q: What is the physical size difference?

A: The X-4035-P-FP32-R dimensions are specified as 1.575" L × 1.575" W (40.00mm × 40.00mm) with a maximum seated height of 0.925" (24.60mm). The X-21 dimensions were not documented. Verify panel cutout and mounting hole spacing compatibility before implementation.

Q: Is the X-4035-P-FP32-R suitable for applications requiring RoHS compliance?

A: Yes. The X-4035-P-FP32-R is RoHS3 compliant, making it appropriate for applications subject to RoHS directives. The X-21 is RoHS non-compliant and should not be used in RoHS-regulated applications.

Q: What is the operating voltage range for the X-4035-P-FP32-R?

A: The X-4035-P-FP32-R operates across a voltage range of 3–32V, with a rated voltage of 32V. This range allows operation at reduced voltages while maintaining the 2.8kHz frequency output.