Application information

TSZ121, TSZ122, TSZ124

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DocID023563 Rev 5

5.5

Input offset voltage drift over temperature

The maximum input voltage drift variation over temperature is defined as the offset

variation related to the offset value measured at 25 °C. The operational amplifier is one of

the main circuits of the signal conditioning chain, and the amplifier input offset is a major

contributor to the chain accuracy. The signal chain accuracy at 25 °C can be compensated

during production at application level. The maximum input voltage drift over temperature

enables the system designer to anticipate the effect of temperature variations.

The maximum input voltage drift over temperature is computed using Equation 1.

Equation 1

Where T = -40 °C and 125 °C.

The TSZ121, TSZ122, and TSZ124 datasheet maximum value is guaranteed by

greater than 1.3.

5.6

Rail-to-rail output

The operational amplifier output levels can go close to the rails: to a maximum of 30 mV

above and below the rail when connected to a 10

kΩ resistive load to V

5.7

Capacitive load

Driving large capacitive loads can cause stability problems. Increasing the load

capacitance produces gain peaking in the frequency response, with overshoot and ringing

in the step response. It is usually considered that with a gain peaking higher than 2.3 dB an

op amp might become unstable.

Generally, the unity gain configuration is the worst case for stability and the ability to drive

large capacitive loads.

Figure 43: "Stability criteria with a serial resistor at VDD = 5 V" and Figure 44: "Stability

criteria with a serial resistor at VDD = 1.8 V" show the serial resistor that must be added to

the output, to make a system stable. Figure 45: "Test configuration for Riso" shows the test

configuration using an isolation resistor, Riso.

∆V

io

∆T

ma x

V

V

–

T

25 °C

–

=

°C