Shown on this slide is a diagram of the LTC6362 driving a SAR ADC. To maximize dynamic range, many new SAR ADCs have fully differential inputs. Differential signals also help reject common mode noise and reduce even-order harmonics. Inside the SAR ADC are capacitors which sample the input and hold the value for use during the conversion process. The process of opening and closing the input switches to these sampling capacitors presents a complex and time-varying load to the circuitry driving them. The LTC6362 is a fully differential amplifier that can accept at its inputs a signal that is already differential, or as is shown in this case it can convert a single-ended input signal to a differential signal. Its outputs are designed with SAR ADC applications in mind, and can swing rail-to-rail, sourcing up to 35mA of current. Feedback resistors are used to set the precise scale – in the example shown, a gain of 0.4 attenuates a ±10V input signal to 0.5V to 4.5V at the output. Internally, the LTC6362 sets its output common mode level to mid-supply. A separate V_OCM pin can be used to set the midpoint of the output to a level different than Vs/2 if desired. The LTC2379-18 is a 1.8Msps 18-bit differential input successive approximation register ADC which can operate with a 2.5V supply and 5V reference. It has a power-saving feature called digital gain compression which rescales the ADC input range to span 10% to 90% of the reference voltage; in this case 0.5 to 4.5V. This allows the LTC6362 amplifier to use a single 5V supply and stay within its most linear range. By eliminating the need for a negative rail, a simpler, lower power, more compact solution is realized.