The LMT90 handles capacitive loading very well. Without any special precautions, the LMT90 can drive any capacitive load. The LMT90 has a nominal 2-kΩ output impedance (as can be seen in the Functional Block Diagram). The temperature coefficient of the output resistors is around 1300 ppm/°C. Taking into account this temperature coefficient and the initial tolerance of the resistors the output impedance of the LMT90 will not exceed 4 kΩ. In an extremely noisy environment it may be necessary to add some filtering to minimize noise pickup. TI recommends that 0.1 μF be added from V_IN to GND to bypass the power supply voltage, as shown in Figure 13. In a noisy environment, it may be necessary to add a capacitor from the output to ground. A 1-μF output capacitor with the 4-kΩ output impedance will form a 40-Hz lowpass filter. Because the thermal time constant of the LMT90 is much slower than the 25-ms time constant formed by the RC, the overall response time of the LMT90 will not be significantly affected. For much larger capacitors this additional time lag will increase the overall response time of the LMT90.

Table 1. Design Parameters