ZSC31150

Fast Automotive Sensor Signal Conditioner

Data Sheet

August 31, 2010

© 2010 Zentrum Mikroelektronik Dresden AG — Rev. 1.07

All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without

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notice.

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Figure 2.2:

Measurement Cycle

2.3.4.

Analog-to-Digital Converter

The ADC is an integrating AD-Converter in full differential switched capacitor technique.

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It can be used as first or second order converter. In the first order mode it is inherently monotone and

insensitive against short and long term instability of the clock frequency. The conversion cycle time depends

on the desired resolution and can be roughly calculated by:

CLK

In the second order mode two conversions are stacked with the advantage of much shorter conversion cycle

time and the drawback of a lower noise immunity caused by the shorter signal integration period. The

conversion cycle time at this mode is roughly calculated by:

CLK

The calculation formulas give an overview about conversion time for one AD-conversion. Refer Calculation

sheet 'ZSC31150 Bandwidth Calculation Sheet' for detailed calculation of sampling time and bandwidth.

The result of the AD conversion is a relative counter result corresponding to the following equation:

number of counts (result of the conversion)

r:

adjusted resolution in bit

differential input/reference voltage of ADC

Start routine

1

Temperature Auto Zero

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n

Pressure measurement

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1

Temp measurement

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n

Pressure measurement

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1

Pressure auto zero

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n

Pressure measurement

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1

CMV

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n

Pressure measurement

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1

SSC/SCC+

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n

Pressure measurement

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1

SSC/SCC-

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n

Pressure measurement