SA26B-08 Replacement: AT-108V, M3933/25-34S

Original Part

SA26B-08

Fairview Microwave

RF Attenuators 8dB 0 Hz ~ 26 GHz 50 Ohms 2W SMA In-Line Module

Alternative Part

AT-108V

Hirose Electric Co Ltd

RF Attenuators 8dB 0 Hz ~ 18 GHz 50 Ohms 2W SMA In-Line Module

M3933/25-34S

Amphenol SV Microwave

RF Attenuators 8dB 0 Hz ~ 18 GHz 50 Ohms 2W SMA In-Line Module

1. AT-108V Substitution Conclusion Substitution is feasible under limited conditions, but carries a risk of critical performance degradation; it is not recommended as a direct replacement. The AT-108V matches the original part SA26B-08 in attenuation value, power rating, impedance, and connector type, satisfying the basic replacement criteria. The core discrepancy lies in its operational frequency range (0–18 GHz), which is significantly narrower than the original part’s 0–26 GHz. Within the 18–26 GHz high‑frequency band, the AT‑108V may fail to maintain specified performance in attenuation accuracy, VSWR, and other parameters, potentially introducing additional insertion loss or reflections. This could lead to degraded performance of the entire RF link at millimeter‑wave frequencies, affecting signal integrity and system noise figure. Substitution is only acceptable if the maximum operating frequency of the application is confirmed not to exceed 18 GHz; otherwise, it is not viable.

2. M3933/25-34S Substitution Conclusion The situation is highly similar to that of the AT‑108V: substitution is possible under constrained conditions, with comparable risks to high‑frequency performance due to insufficient frequency coverage. The key specifications of the M3933/25‑34S—8 dB attenuation, 2 W power handling, and SMA interface—align exactly with those of the original SA26B‑08. However, its frequency range (0–18 GHz) is likewise 8 GHz narrower than the original part’s (0–26 GHz). This gap directly prevents the part from covering Ku‑band (18–26.5 GHz) and portions of the K‑band. If forced to operate within 18–26 GHz, the attenuation value may deviate from its nominal specification and impedance mismatch may worsen, thereby degrading system gain flatness and increasing measurement or communication errors. Although its manufacturer, Amphenol SV Microwave, is a well‑known supplier in high‑reliability fields, this particular part is not designed for 26 GHz broadband operation. It is suitable only for applications where the operating band is strictly limited to 18 GHz or below; otherwise, it cannot serve as a substitute.

Analysis ID: BFC9-6B0B000

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