ZSSC3017 16-bit IC offers DSP-based linearisation

ZMD AG has introduced a 16-bit sensor signal-conditioning IC (SSC) that is suitable for altimeter/barometer systems, data merging with GPS receivers, medical gas and infusion pumps and robotics.

Developed for resistive bridge sensors, the ZSSC3017 combines high accuracy amplification, 16-bit precision analogue-to-digital conversion, and an 18-bit DSP for linearisation and calibration functions.

The 16-bit precision and on-chip DSP-based linearisation make the ZSSC3017 accurate enough for demanding applications such as portable altimeter and barometer systems and weather-forecasting equipment.

In heating, ventilating and air-conditioning (HVAC) systems, its precision permits accurate sensing of airflow within buildings, allowing better and more energy-efficient building heating and cooling.

New types of consumer items, such as motion-sensing sport equipment or multi-function watches, can also benefit from the ZSSC3017's precision.

Medical gas control, medical infusion pumps, ambulatory non-invasive pump systems and occlusion detection systems all require this level of precision.

The conversion characteristics of resistive sensor bridges are generally non-linear and temperature-dependent.

Sophisticated signal processing, for amplification, linearisation and compensation of the effects of the temperature, is required.

To deliver the highest possible accuracy, the ZSSC3017 features an analogue front-end with multiple flexible programming options, including an on-chip temperature sensor and fully differential signal paths.

The IC topology uses a second-order charge-balancing ADC leading to less than +/-0.5 per cent (FSO) accuracy error over the full industrial temperature range of -40C to +85C.

A fully programmable differential gain amplifier optimally works with sensor-signal ranges from 12.5-160mV/V.

The device can be adapted to different sensor-signal range centres and features an internal auto-compensated temperature sensor.

An on-chip 18-bit DSP implements the calibration math and sophisticated second-order error correction for temperature offset, drift and non-linearity.

All calibration data is stored in on-chip EEPROM and the system can be re-calibrated in the field.

Performing all of the error correction in the ZSSC3017 allows the device to deliver a fully corrected digital-output signal, which simplifies the design of the rest of the system and minimises the bill of materials as well as system power consumption.

ZMDI's one-shot calibration concept minimises calibration costs.

Calibration is accomplished easily with a PC-based program using a two-wire, I2C-based interface, and can be done at high speed in production.

No external trimming components are required, which reduces the bill of materials and manufacturing costs.

ZMDI's development kit makes it simple to implement calibration routines.

The ZSSC3017 operates on supply voltages from 2.7 to 5.5V and over a temperature range of -40C to +85C.

Accuracy is +/-0.5 per cent FSO over the full temperature range.

Noise performance of far less than 1.5uV (rms, input-referred) is possible.

Power consumption during sleep mode is below 2uA at 25C.

The layout of the ZSSC3017 is customised for die bonding with a sensor.

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