Example - 1

A 100 PF capacitor has a maximum charging current of 150 µA. What is the slew rate?

Solution:

C = 100 PF=100 x 10^-12 F
I = 150 µA = 150 x 10^-6 A

Slew rate is 1.5 V / µs.

Example - 2

An operational amplifier has a slew rate of 2 V / µs. If the peak output is 12 V, what is the power bandwidth?

Solution:

The slew rate of an operational amplifier is

As for output free of distribution, the slews determines the maximum frequency of operation fmax for a desired output swing.

so    
So bandwidth = 26.5 kHz.

Example - 3

For the given circuit in fig. 1. I_in(off) = 20 nA. If V_in(off) = 0, what is the differential input voltage?. If A = 10⁵, what does the output offset voltage equal?

Fig. 1

Solutin:

I_in(off) = 20 nA
V_in(off) = 0

(i) The differential input voltage = I_in(off) x 1k = 20 nA x 1 k = 20µ V

(ii) If A = 10⁵ then the output offset voltage V_in(off) = 20 µ V x 10⁵ = 2 volt

Output offset voltage = 2 volts.

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