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# ADL5201 Common Mode Input Voltage

Hi,

In table 1 of the ADL5201 data sheet it states that the input can be +/-10V p-p if the attentaution is set at -11.5db.

Yet, in table 2 the absolute maximum VIN+ and VIN- specifications provided don't tally with the above figure.

Does anyone know what the true VN+ and VIN- Maximum/Minimum ranges are?

Thanks Anthony

• Hi Anthony,

The 10.8 V p-p swing mentioned in Table 1 is the  maximum AC signal swing allowed when the amplifier is set to minimum gain. The input  common mode voltage is 1.5 V. ( see Table1)

The V+ - V- voltages listed in table 2, are the Absolute Maximum DC voltage levels that should be applied to the input pins of the ADL5201.

• Hi,Jim;

Is the input of ADL5201 self-biased so we do not need provide a DC bias?

Donald

• The input of the ADL5201 self biases to 1.6 V. See the INPUT SYSTEM section on page 17, of the ADL5201 datasheet.

• Hi,

I still don't get the full picture.

With a common mode voltage of +1.5 V, for example,  the negative is allowed to swing down to -1.2 V (presumably). resulting in a  2.7 V peak swing. At the same time, for example, the positive input can swing up to +3.6 V, resulting in a 2.1 V peak for a total of 4.8 V p-p (not 10.8V as per the data sheet).

Assuming that the positive input could also swing by +2.7 V, the total would now be 5.4 V p-p. And, assuming the 10.8 V specification quoted is with s source impedance of 150 Ohm (the impedance of the device) then the 10.8 V figure comes into the picture.

But, there are a lot of assumptions in the above.

Is there a simpler explanation for how the 10.8V p-p is derived?

Regards Anthony

• The part is not intended for dc coupled use. the 10.8V p-p is the maximum AC signal swing allowed at the input at the minimum gain setting 111111, and assumes a 150 ohm driving impedance. . The 10.8 V p-p swing corresponds to a power level of +19.88 dBm re 150 ohms.

• This question has been assumed as answered either offline via email or with a multi-part answer. This question has now been closed out. If you have an inquiry related to this topic please post a new question in the applicable product forum.

Thank you,