This simple block diagram shows the ADuC845 – a typical Sigma-Delta ADC with an 8052 core. Note that the analog area is highlighted in blue and contains 2 Sigma Delta ADCs. The top ADC (ADC0) contains a programmable gain amplifier, multiple input channels that can be sampled in differential or single-ended mode, and diagnostic current sources for detecting open input circuits or shorts. The second ADC (ADC1) contains multiple input channels that can be sampled in differential or single-ended mode (maximum of 8 inputs in single-ended mode) and a temperature sensor channel.