L407CDT RF PIN Diode Equivalent & Substitute Parts

Part Overview

The L407CDT is an RF PIN diode manufactured by CEL, designed for RF switching and attenuation applications. It features a 180V peak reverse voltage rating, 1W power dissipation capability, and is packaged in a DO-41 axial glass configuration. The part is currently classified as obsolete, making equivalent substitutes necessary for new designs and ongoing production requirements.

Substiute Parts

L407CDT

CELIn Stock: 698L407CDT Datasheet

Current PartRFQ

L8104

CELIn Stock: 1269L8104 Datasheet

MFR RecommendedRFQ

L9204F

CELIn Stock: 1043L9204F Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for RF PIN diodes is determined by the following critical parameters:

• Diode Type: Must be PIN - Single configuration
• Voltage - Peak Reverse (Max): Must equal or exceed 180V
• Power Dissipation (Max): Must meet or exceed application requirements
• Operating Temperature: Must support the thermal environment
• Capacitance and Resistance characteristics: Must be compatible with RF circuit performance

The two substitute parts listed below maintain the core 180V voltage rating and PIN diode topology. Substitution feasibility depends on whether the application can accommodate package changes and the specific RF frequency and power handling requirements of the circuit.

Parameter Comparison

Engineering Selection Recommendations

Both L8104 and L9204F are active products with ROHS3 compliance, making them suitable for modern production environments where the L407CDT obsolescence creates supply constraints.

L8104 offers higher power dissipation (3W vs 1W) and maintains the 175°C operating temperature rating of the original part. The MELF package provides a surface-mount alternative to the axial configuration. Current rating is reduced to 50 mA, which may limit applications requiring the full 100 mA capability of the L407CDT.

L9204F maintains the 1W power dissipation specification and achieves lower forward resistance (650mOhm vs 800mOhm), potentially improving RF efficiency. The SOD-123T package is a compact surface-mount option. Operating temperature is reduced to 150°C, which may be a constraint in high-temperature applications. Current rating is also 50 mA.

Selection between these substitutes depends on package compatibility with existing PCB designs, thermal environment requirements, and forward current demands of the specific RF circuit.

Frequently Asked Questions (FAQ)

Q: Can L8104 or L9204F directly replace L407CDT in existing designs?

A: Direct replacement depends on circuit requirements and PCB layout. Both substitutes maintain the 180V voltage rating and PIN diode topology. However, package changes (from DO-41 axial to MELF or SOD-123T surface-mount) require PCB redesign. Current rating reduction from 100 mA to 50 mA must be evaluated against circuit demands.

Q: What is the primary difference between L8104 and L9204F?

A: L8104 provides 3W power dissipation and 175°C operating temperature, suitable for higher-power RF applications. L9204F maintains 1W power dissipation with lower forward resistance and operates to 150°C. Current ratings are identical at 50 mA for both.

Q: Are both substitutes RoHS compliant?

A: Yes. Both L8104 and L9204F are ROHS3 compliant, meeting modern environmental and regulatory requirements. The L407CDT RoHS status is not specified in available documentation.

Q: How do capacitance values affect RF circuit performance?

A: Capacitance values are provided at specific bias voltages and frequencies. L9204F exhibits the lowest capacitance (0.9pF), followed by L8104 (1.2pF), and L407CDT (2pF). Lower capacitance generally reduces parasitic effects at higher RF frequencies. Circuit simulation is necessary to confirm performance impact for specific frequency bands.

Q: What packaging considerations apply to substitution?

A: L407CDT uses DO-41 axial packaging for through-hole assembly. L8104 uses MELF (surface-mount), and L9204F uses SOD-123T (surface-mount). Package selection affects PCB layout, assembly process, and mechanical integration. Existing through-hole designs require redesign for surface-mount alternatives.