DocID024317 Rev 2

19/33

TSU101, TSU102, TSU104

Application information

33

Equation 5

as a function of the maximum operating voltage and the absolute maximum rating (as

recommended by JEDEC rules).

different measurement conditions (see Equation 6).

Equation 6

calculated number of months (Equation 7).

Equation 7

duration.

4.5

Schematic optimization aiming for nanopower

To benefit from the full performance of the TSU10 series, the impedances must be

maximized so that current consumption is not lost where it is not required.

For example, an aluminum electrolytic capacitance can have significantly high leakage. This

leakage may be greater than the current consumption of the op-amp. For this reason,

ceramic type capacitors are preferred.

For the same reason, big resistor values should be used in the feedback loop. However,

there are three main limitations to be considered when choosing a resistor.

1.

When the TSU10x series is used with a sensor: the resistance connected between the

sensor and the input must remain much higher than the impedance of the sensor itself.

2.

, a bigger resistor value generates

even more noise.

3.

Leakage on the PCB: leakage can be generated by moisture. This can be improved by

using a specific coating process on the PCB.

Months

×

12 months

24 h

365.25 days

×

()

⁄

×

=

⁄

==

months

()

------------------------------

=

nV

Hz

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