SBVS336A September 2021 – May 2022 TPS7A94
Figure 7-1 shows a simplified regulation circuit, where the input signal (VNR/SS) is generated by the internal current source (INR/SS) and the external resistor (RNR/SS). Because the error amplifier is always operating in unity-gain configuration, the LDO output voltage is directly programmed by the VNR/SS voltage. The VNR/SS reference voltage is generated by an internal low-noise current source driving the RNR/SS resistor and is designed to have very low bandwidth at the input to the error amplifier through the use of a low-pass filter (CNR/SS || RNR/SS).
This unity-gain configuration, along with the highly accurate INR/SS reference current, enables the device to achieve excellent output voltage accuracy; though, the RNR/SS accuracy can become the limiting factor when operating at low output voltage. The low dropout voltage (VDO) enables reduced thermal dissipation and achieves robust performance. This combination of features makes this device an excellent voltage source for powering sensitive analog low-voltage devices.