AD7709 is a complete analog front end for low frequency measurement applications. It contains a 16-bit-ADC, selectable reference inputs, three switchable matched excitation current sources, low-side power switches, and a digital I/O port. It can be configured as two fully differential input channels or four pseudo-differential input channels. Signals can be converted directly from a transducer without the need for signal conditioning. This device operates from a 32.768KHz crystal with an on-chip PLL generating the required internal operating frequency. The output data rate from the part is software programmable. The p-p resolution from the part varies with the programmed gain and output data rate. It is widely used in application such as sensor measurement, temperature measurement, pressure measurements, weigh scales, portable instrumentation, 4–20mA loops etc.