ZSSC3154

Automotive Sensor Signal Conditioner with Dual Analog Output

Evaluation Kit

March 13, 2012

© 2012 Zentrum Mikroelektronik Dresden AG

— Rev. 1.00

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The “updated” LED displays the software configuration status compared with the attached ZSSC3154’s

register content. If the content is identical, the LED is green (on).

3.4.3.

Analog Front End (AFE) Adjustment

The ZSSC3154 has different options to adapt the analog front end

(AFE) to the specific sensing element.

The “Sensor - Full Bridge” and

“Half Bridge” sections (shown in Figure 3.5) influence the program-

mable gain amplifier (PGA) and extended zero compensation.

The s

ensor’s span or sensitivity is defined by mV/V and is referenced

to the bridge supply voltage.

Different reference voltages can be selected for the Half Bridge, which

are entered as a percentage of the positive analog supply voltage

(VDDA).

Refer to the ZSSC3154 Data Sheet for details about AFE and XZC

settings.

The polarity of the sensor signal can be selected by the

button

and can be changed if the PCB layout requires swapped input pins.

3.4.4.

Temperature Sensor Selection

The next stage in the AFE is the multiplexer that selects the input

signal for measuring temperature (see Figure 3.6). The ZSSC3154

can use three different temperature channels: one internal and two

external. Each input can be used for calibration calculation. External

temperature sensors can be used as an optional additional output

signal during Normal Operating Mode (NOM).

3.4.5.

ADC Settings

The last stage of the AFE is the analog-to-digital converter (ADC).

The signal path within the AFE is designed in fully differential switched

capacitor technology with a selectable resolution of 13 or 14 bits. It is

necessary to provide an ADC input within 10% to 90% of the ADC

range of the application.

Refer to the ZSSC3154 Data Sheet for details about ADC settings.

If the analog input voltage does not fit the ADC range and an

underflow or overflow occurs, the “Range Shift” option can be used for

fine-tuning

. A lower “Span” setting in the “Sensor Adaptation” section

can also be useful for fitting the ADC range.

The ADC resolution first step of the conversion integration phase can

be adjusted, which influences the integration time. Select a conver-

sion time that is as long as possible to secure a high degree of noise

suppression.

If enabled, the clock divider makes the ADC operate with half of the

clock frequency. This increases accuracy and linearity.

Figure 3.5 Bridge Sensor Adaptation

Figure 3.6 Temperature Sensor

Figure 3.7 ADC Adjust