Semtech has released the SX8725, a single-channel member of the company’s award-winning data acquisition product platform. The SX8725 features one differential input but delivers very high precision through its ZoomingADC™ functionality.

ZoomingADC is the combination of a full 16-bit ADC and a powerful preamplifier that allows the device to “zoom in” (with a programmable gain from 0.1 to 1000) on a small portion of the analog signal. The SX8725 can lower the cost of implementing portable sensing systems by allowing manufacturers to use lower-cost sensors without sacrificing accuracy. It advantageously replaces a slower and more expensive 24 bits ADC.

The SX8725 saves designers more than 50% of the cost of an ADC by obviating the need for a 24-bit device. With the right combination of the signal chain elements integrated, the SX8725 saves on preamps and the extra premium for extra bits. The SX8725 generates this accuracy in the smallest package for this class of device. Sensor manufacturers can thus add value to their offering by providing a digital output from the sensor enclosure.

The SX8725 converts analog sensor data into a digital signal for processing and can be used with a wide array of pressure sensing, chemical sensing, load cells or temperature monitoring sensors. The SX8725 operates at voltages between 2.4V and 5.5V making it compatible with most portable devices. Its current requirement is low enough to be integrated in loop-powered 4-20mA systems.
The most notable feat of the ZoomingADC™ devices is the ability to provide a direct connection of the sensor. Because of it’s highly programmable preamplifier chain, it can directly read sensors as different as 5 V full scale chemical and 2 mV full scale magnetic sensors. For example:

• Pressure sensing:
  Pressure sensors are most often Wheatstone bridges with 0.5 kOhm to 10 kOhm impedance. The bridge full scale signal is often between 10 mV and 50 mV with a large offset.
• Temperature sensing:
  Temperature sensors are most often resistive elements. Reading these as Wheatstone bridges increase the precision of the measurement.
• Magnetic sensing:
  Precision magnetic sensing is often done with AMR technology (anisotropic magneto-resistors). These devices come as Wheatstone bridges with very small sensitivity, down to 2mV full scale for earth field sensors (compasses). The SX8724 can interface this sensor directly.

Additionally, the sensor bridge can be biased on and off to lower the mean current consumption of the sensor.

The SX8725 features a single differential input with two digital I/Os, and is part of a complete platform of ultra small data acquisition devices from Semtech, including the SX8723, which has two differential inputs or four single-ended inputs and two digital I/Os, and the SX8724, which has three differential inputs or six single-ended inputs and four parallel I/Os. All three products have I2C bus interface and an embedded voltage reference.

The SX8725 comes in a 4x4 mm MLPD12 leadless 12-pin package that is RoHS and WEEE compliant.