In general, the trend towards an increasing number of inputs coupled with smaller form factors requires lower power, smaller size and cost for ICs, and better diagnostics to catch fault conditions. These modules have to be protected against surges and transients. Finally, overall good system accuracy and resolution is required. Design considerations for signal conditioning include whether the input is single ended or differential like when connected to strain gauges and bridge topologies. Because the 4-20 mA loops can run for large distances, the common mode range must be large and the circuitry must protect for over voltages and also reject common mode interference from motors, AC power lines and other sources which inject noise on the analog inputs. Since we could be measuring signals from thermocouples and other low level sensors, there must be low offset voltages as well as minimal drift of the offset voltage over temperature. Precision bipolar op amps are used extensively in applications where the source impedance is low, such as a thermocouple amplifier, and where voltage errors offset voltage and drift, are crucial to accuracy. PGAs (Programmable Gain Amplifiers) can be used when the input voltage range can vary over multiple sensor types. Differential amps can be used when the common mode range is greater than the power supply rails and INAs (Instrumentation Amplifiers) should be used to amplify low level signals where the maximum common mode voltage is within the supply range. System resolution is determined by the measurement channel ADC. Sigma delta ADCs are used for high resolution (24 bit) and have the advantage of performing anti-aliasing filtering and 50/60 Hz notch filtering in the digital domain. SAR ADCs are frequently the converter of choice for medium resolution (16 bit and 12 bit) especially when there is a mux in front of the ADC. Many ADCs integrate the MUX in front of the ADC. Finally, the amplifier driving the ADC must be selected carefully to preserve the dynamic signal characteristics and maintain performance. Visit www.ti.com to identify the right amplifier and data converter products for a desired application. In addition to signal conditioning, other considerations include high efficiency and integration for DC-DC converters along with smaller packages. Picking a DC-DC converter with a large input range will also protect against supply transients. To isolate the field side from the control side, isolated DC-DC converter modules can be used in addition to digital isolators using TI’s capacitive technology for the SPI bus interface between the A/D converters and the main controller. Finally, using LDOs with a good PSRR (Power Supply Rejection Ratio) to supply the precision analog circuitry will reduce the power supply ripple and preserve system accuracy and resolution.