ZSC31150 Datasheet

© 2016 Integrated Device Technology, Inc.

10

December 6, 2016

2.

Circuit Description

Note: This data sheet provides specifications and a general overview of ZSC31150 operation. For details of operation, including configuration

settings and related EEPROM registers, refer to the ZSC31150 Functional Description.

2.1 Signal Flow

The ZSC31150’s signal path includes both analog (shown in blue in Figure 2.1) and digital (pink) sections. The analog path is differential; i.e.,

the differential bridge sensor signal is handled internally via two signal lines that are symmetrical around a common mode potential (analog

ground = VDDA/2), which improves noise rejection.

Consequently, it is possible to amplify positive and negative input signals, which are located within the common mode range of the signal

input.

Figure 2.1 Block Diagram of the ZSC31150

PGA

TS

ADC

CMC

ROM

RAM

EEPROM

DAC

BAMP

ZACwire™

Analog Block

Digital Block

ZSC31150

Digital

Data I/O

Analog

Out

The differential signal from the bridge sensor is pre-amplified by the programmable gain amplifier (PGA). The multiplexer (MUX) transmits the

signals from either the bridge sensor, the external diode, or the separate temperature sensor to the analog-to-digital converter (ADC) in a

specific sequence (the internal pn-junction (TS) can be used instead of the external temperature diode). Next, the ADC converts these signals

into digital values.

The digital signal correction takes place in the calibration microcontroller (CMC). It is based on a correction formula located in the ROM and

sensor-specific coefficients stored in the EEPROM during calibration. Depending on the programmed output configuration, the corrected

be programmed into the EEPROM via the digital interfaces.

2.2 Application Modes

For each application, a configuration set must be established (generally prior to calibration) by programming the on-chip EEPROM regarding

to the following modes:

Sensor Channel



Sensor mode: ratiometric bridge excitation in voltage or current supply mode.



Input range: the gain adjustment of the AFE with respect to the maximum sensor signal span and the zero point of the ADC have to be

chosen.



An additional analog offset compensation, the Extended Zero-Point Compensation (XZC), must be enabled if required; e.g., if the sensor

offset voltage is close to or larger than the sensor span.



the sampling rate, signal integration time, and, as a result, the noise immunity.

Temperature



Temperature measurement: the source for the temperature correction must be chosen.