OA1MPA Datasheet, PDF (16/28 Pages) STMicroelectronics – Medical instrumentation

Application information
4
Application information
OA1MPA, OA2MPA, OA4MPA
4.1
Operating voltages
The OA1MPA, OA2MPA, and OA4MPA series of devices can operate from 1.5 V to 5.5 V.
The parameters are fully specified for 1.8 V, 3.3 V, and 5 V power supplies. However, they
are very stable in the full V_CC range and several characterization curves show OA1MPA,
OA2MPA, and OA4MPA device characteristics at 1.5 V. In addition, the main specifications
are guaranteed in the extended temperature range from -40 °C to +125 °C.
4.2
Rail-to-rail input
The OA1MPA, OA2MPA, and OA4MPA devices have a rail-to-rail input, and the input
common mode range is extended from V_CC-- 0.1 V to V_CC+ + 0.1 V.
4.3
Rail-to-rail output
The output levels of the OA1MPA, OA2MPA, and OA4MPA operational amplifiers can go
close to the rails: to a maximum of 40 mV below the upper rail and to a maximum of 75 mV
above the lower rail when a 10 k resistive load is connected to V_CC/2.
4.4
Input offset voltage drift over temperature
The maximum input voltage drift over the temperature variation is defined as the offset
variation related to 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
_----V_{---T--i-o- = max V-----i-o-----T---T-----––-----V2---5-i-o----C--2---5------C------}
with T = -40 °C and 125 °C.
The datasheet maximum value is guaranteed by a measurement on a representative
sample size ensuring a C_pk (process capability index) greater than 1.33.
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