AN4369

Gain error between two TSC products from

different batches

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Gain error between two TSC products from different

batches

Even if the internal resistances are

well matched and with a value around 5 kΩ, the gain

may vary from one TSC product to another by as much as ±20 %. This is due to process

variation as shown in the equation below:

Where:

εα is the precision of internal resistances up to ±20 %

εβ is the precision of the external resistances

So,

Consequently, the error on the gain (%) is represented by:

Table 1 gives an example at 25 °C.

Table 1: Gain error vs. series resistor Rs1

Rs1

(Ω)

Theoretical

gain

Gain con

sidering process variation (εα = 20 %) and

Rs1 (εβ = -1 %)

Gain error

(%)

50

19.80

19.84

0.21

100

19.60

19.68

0.41

200

19.23

19.38

0.80

500

18.18

18.52

1.87

1000

16.67

17.25

3.38