SBOS831B December 2016 – June 2021 THS4552
PRODUCTION DATA
The THS4552 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 2.7 V (10% low on a 3 V nominal supply) and 5.4 V (8% high on a 5 V nominal supply). Supply decoupling is required, as described in Section 7.7. Split (or bipolar) supplies can be used with the THS4552, as long as the total value across the device remains less than 5.5 V (absolute maximum). The thermal pad on the RTW package is electrically isolated form the die; connect the thermal pad (RTW package only) to any power or ground plane for reduced thermal impedance to the junction temperature. This pad must be connected to some power or ground plane and not floated.
For the best input offset voltage drift, the THS4552 uses a proportional to absolute temperature (PTAT) quiescent current biasing scheme. This approach gives a positive over temperature variation in supply current. Figure 10-1 shows the 5 V supply current over a wide TJ range for a number of tested units. The tables in Section 6.5 report the typical and range on this supply current temperature coefficient for both 5 V and 3 V supply operation.
Using a negative supply to deliver a true swing to ground output when driving SAR ADCs can be desired. Although the THS4552 quotes a rail-to-rail output, linear operation requires approximately 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 can accept the 3 V to 5 V positive supply input used by the THS4552 and provides a fixed –230 mV supply for the negative power supply. Using the LM7705 provides an effective solution, as discussed in the Extending Rail-to-Rail Output Range for Fully Differential Amplifiers to Include True Zero Volts.