7.3.3 Current Output Conversion to Voltage

The minimum voltage drop across the LMT01-Q1 must be maintained at 2.15 V during the conversion cycle. After the conversion cycle, the minimum voltage drop can decrease to 2.0 V. Thus the LMT01-Q1 can be used for low voltage applications. See Application Information for more information on low voltage operation and other information on picking the actual resistor value for different applications conditions. The resistor value is dependent on the power supply level and the variation and the threshold level requirements of the circuitry the resistor is driving (that is, MCU, GPIO, or Comparator).

Stray capacitance can be introduced when connecting the LMT01-Q1 through a long wire. This stray capacitance influences the signal rise and fall times. The wire inductance has negligible effect on the AC signal integrity. A simple RC time constant model as shown in Figure 20 can be used to determine the rise and fall times.

Figure 20. Simple RC Model for Rise and Fall Times

Equation 2.

where

• RC as shown in Figure 20
• V_HL is the target high level
• the final voltage V_F = 125 µA × R
• the start voltage V_S = 34 µA × R

For the 10% to 90% level rise time (t_r), Equation 2 simplifies to:

Equation 3.

Take care to ensure that the LMT01-Q1 voltage drop does not exceed 300 mV under reverse bias conditions, as given in the Absolute Maximum Ratings.