ZSC31010 Datasheet

© 2016 Integrated Device Technology, Inc.

12

January 20, 2016

2.2.

Analog Front End

2.2.1.

Bandgap/PTAT and PTAT Amplifier

The highly linear Bandgap/PTAT provides the PTAT signal to the ADC, which allows accurate temperature con-

version. In addition, the ultra-low ppm-Bandgap provides a stable voltage reference over temperature for the

operation of the rest of the IC.

The PTAT signal is amplified through a path in the pre-amplifier (PREAMP) and fed to the ADC for conversion.

The most significant 12 bits of this converted result are used for temperature measurement and temperature

correction of bridge readings. When temperature is output in Digital Mode, only the most significant 8 bits are

given.

2.2.2.

Bridge Supply

also includes a switched transistor to interrupt the bridge current via the Bsink pin. The transistor switching is

synchronized to the A/D-conversion and released after finishing the conversion. To utilize this feature, the low

supply of the bridge should be connected to Bsink instead of ground.

Depending on the programmable update rate, the average current consumption (including bridge current) can be

reduced to approximately 20%, 5% or 1%.

2.2.3.

PREAMP Block

The differential signal from the bridge is amplified through a chopper-stabilized instrumentation amplifier with very

high input impedance, designed for low noise and low drift. This PREAMP provides gain for the differential signal

sequence performed by the digital core includes an auto-zero sequence to null any drift in the PREAMP state

over temperature.

The PREAMP is nominally set to a gain of 24. Other possible gain settings are 6, 12, and 48.

The inputs to the PREAMP from the VBN/VBP pins can be reversed via an EEPROM configuration bit.

2.2.4.

Analog-to-Digital Converter (ADC)

A 14-bit/1 ms 2

verter, designed in full differential switched-capacitor technique, is used for converting the various signals to the

digital domain. This principle offers the following advantages:

Four selectable values for the zero point of the input voltage allow the conversion to adapt to the sensor’s offset

parameter. The conversion rate varies with the programmed update rate. The fastest conversion rate is