The THS452x family is principally intended to operate with a nominal single-supply voltage of +3 V to +5 V. Supply-voltage tolerances are supported with the specified operating range of 2.5 V (10% low on a 3-V nominal supply) and 5.5 V (8% high on a 5-V nominal supply). Supply decoupling is required, as described in the Application and Implementation. Split (or bipolar) supplies can be used with the THS452x family, as long as the total value across the device remains less than 5.5 V (absolute maximum).
Using a negative supply to deliver a true swing to ground output in driving SAR ADCs may be desired. While the THS452x family quotes a rail-to-rail output, linear operation requires approximately a 200-mV headroom to the supply rails. One easy option for extending the linear output swing to ground is to provide the small negative supply voltage required using the LM7705 fixed –230-mV, negative-supply generator. This low-cost, fixed negative-supply generator accepts the 3- to 5-V positive supply input used by the THS452x and provides a –230-mV supply for the negative rail. Using the LM7705 provides an effective solution, as shown in the TI Designs TIDU187, Extending Rail-to-Rail Output Range for Fully Differential Amplifiers to Include True Zero Volts.