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ADL5304 Recommended for New Designs
The ADL5304 is a high speed logarithmic converter with fast response and low noise over a 200 dB (1 pA to 10 mA) measurement range. The ADL5304 provides...
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INUM pin voltage of EVAL- ADL5304

Kazu

on Sep 12, 2022

Category: Hardware

Product Number: ADL5304

Hi,

How is the voltage on the INUM pin determined?

I pulled up the INUM pin to 2 V and measured the voltage. I thought it was 1.5 V, but when I measured it, it was 1.1 V. How is 1.1 V determined?

Regards,

Kazu

ADIApproved

on Sep 12, 2022 8:43 PM
Hello Kazu,

What voltmeter did you use for the measurement? We normally recommend that customer does NOT measure voltage at INUM, because impedance is so high, most common lab voltmeters with 10M ohm input impedance causes the voltage to be altered by the measurement.

If you have a HP/Agilent/KS model 34401A, there is a special setting from the front panel that provides around 10,000 M ohm input resistance for the DCV range. Use this special setting if a measurement must be made.

Alternatively, one could measure the VLOG voltage at the output, to see if it is correct, given the input current INUM=(2-1.5)/1M = 0.5uA. -Bruce H.
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INUM pin voltage of EVAL- ADL5304