5

Application information

5.1

Operating voltages

The TSV78x device can operate from 2.0 to 5.5 V. The parameters are fully specified at 2.0 V, 3.3 V and 5 V

power supplies. However, the parameters are very stable over the full VCC range, and several characterization

curves show the TSV78x device characteristics over the full operating range. Additionally, the main specifications

are guaranteed in extended temperature range from -40 to 125 °C.

5.2

Input offset voltage drift over the temperature

The maximum input voltage drift variation overtemperature 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 (Vio) 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 overtemperature enables the system designer to anticipate the effect of temperature variations.

The maximum input voltage drift overtemperature is computed using Eq. (1).

∆Vio∆T=maxVioT−Vio25°C

T−25°C T=−40°C and T=125°C

(1)

The datasheet maximum value is guaranteed by a measurement on a representative sample size ensuring a Cpk

(process capability index) greater than 1.3.

5.3

Long term input offset voltage drift

To evaluate product reliability, two types of stress acceleration are used:

•

Voltage acceleration, by changing the applied voltage

•

Temperature acceleration, by changing the die temperature (below the maximum junction temperature

allowed by the technology) with the ambient temperature.

The voltage acceleration has been defined based on JEDEC results, and is defined using Eq. (2).

AFV=eβ.VS−VU

(2)

Where:

AFV is the voltage acceleration factor

β is the voltage acceleration constant in 1/V, constant technology parameter (β = 1)

VS is the stress voltage used for the accelerated test

VU is the voltage used for the application

The temperature acceleration is driven by the Arrhenius model, and is defined in Eq. (3).

AFT=eEak. 1TU−1TS

(3)

Where:

AFT is the temperature acceleration factor

Ea is the activation energy of the technology based on the failure rate

k is the Boltzmann constant (8.6173 x 10-5 eV . K-1)

TU is the temperature of the die when VU is used (K)

TS is the temperature of the die undertemperature stress (K)

The final acceleration factor, AF, is the multiplication of the voltage acceleration factor and the temperature

acceleration factor (Eq. (4)).

AF=AFT.AFV

(4)

TSV781, TSV782

Application information

DS14011 - Rev 7

page 18/34