SA3R-20 Replacement: AT-120V, M3933/14-04S

Original Part

SA3R-20

Fairview Microwave

RF Attenuators 20dB 0 Hz ~ 3 GHz 50 Ohms 2W SMA In-Line Module

Alternative Part

AT-120V

Hirose Electric Co Ltd

RF Attenuators 20dB 0 Hz ~ 18 GHz 50 Ohms 2W SMA In-Line Module

M3933/14-04S

Amphenol SV Microwave

RF Attenuators 20dB 0 Hz ~ 12.4 GHz 50 Ohms 2W SMA In-Line Module

1. AT-120V Substitution Conclusion Based on core parameters (20 dB attenuation, 2W power rating, 50Ω impedance, SMA interface), the AT-120V is a direct functional replacement for the SA3R-20. Its primary advantage lies in its significantly wider operational frequency range (0–18 GHz), which far exceeds the original part's 3 GHz limit. This extended bandwidth ensures stable performance in higher frequency applications (e.g., C, X, and Ku bands). However, this frequency extension necessitates verification of its RF performance—specifically attenuation accuracy and VSWR—across the intended operational band. For systems operating strictly below 3 GHz, this advantage may not be utilized and could come at a higher cost. Electrically, the devices are fully compatible, with the AT-120V offering greater frequency headroom.

2. M3933/14-04S Substitution Conclusion The M3933/14-04S matches the original SA3R-20 in all fundamental specifications (20 dB, 2W, 50Ω, SMA), providing a solid basis for direct electrical substitution. The key difference is its extended frequency range up to 12.4 GHz, significantly higher than the original's 3 GHz ceiling. This indicates the component is suitable for medium-to-high frequency microwave circuits (e.g., portions of S and C bands) and typically incorporates internal design optimizations (e.g., resistive material, structure) for improved high-frequency response. When used within the original design band (below 3 GHz), its high-frequency capability is surplus but offers enhanced performance margin and design headroom. If future system upgrades to higher frequencies are anticipated, this part is the preferable choice. During substitution, attention should be paid to its specific high-frequency performance metrics to ensure they meet system requirements.

Analysis ID: CCF5-1E59000

Based on part parameters and for reference only. Not to be used for procurement or production.