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ADL5910 device to device variation

Dear community,

I want to use a RF power detector IC in configuration with a directional coupler for a simple power amplifier VSWR protection circuit. My first choice is ADL5910 because of its simplicity, but I have a question regarding detectors in general. From ADL5910 datasheet, without calibration for a given VIN- (threshold) voltage, actual input power triggering latch can vary from device to device by quite a bit (±2.5 dB). I don't need precise measurement, but the 5 dB range could be too large. So my question is: is there a way to avoid calibration on every single IC? Maybe I should be looking for another one? For example: LTC5530 datasheet does not explicitly mention device-to-device variation (so I'm assuming that information is contained within "Vout (No RF Input)" Min-Typ-Max?). Or is this variation just an inherent part of the semiconductor process and for more precise thresholds a calibration is always required?

Best regards,

  • Greetings Konrad,

    Pretty much all of the fully integrated RF detectors from any manufacturer I know of will have part-to-part variation in their response. This includes ADL5910 and LTC5530. The variation is inherent to the semiconductor mass production process. Variations usually show up more at the lower power levels. So in general, we always recommend that end users incorporate a provision for individual calibration. For simple, low volume applications it could be as simple as one or two trimpots. For larger systems tested by ATE, the trims are generally stored in system non-volatile memory. The small serial EEPROM chips are useful also, as are digital trimpots. Lots of solutions exist.