SBASAC9A February 2022 – July 2022 AMC23C11
PRODUCTION DATA
The voltage on the REF pin determines the trip threshold of the comparator. The internal precision current source forces a 100-μA current through an external resistor connected from the REF pin to GND1. The resulting voltage across the resistor (VREF) equals the trip threshold, see Figure 7-1. Place a 100-nF capacitor parallel to the resistor to filter the reference voltage. This capacitor must be charged by the 100-μA current source during power-up and the charging time may exceed the high-side blanking time (tHS,BLK). In this case, as shown in Figure 7-2, the comparator may output an incorrect state after the high-side blanking time has expired until VREF reaches its final value. See the Section 7.3.5 section for more details on power-up behavior.
The reference pin can be driven by an external voltage source to change the comparator threshold during operation. However, do not drive VREF dynamically across the VMSEL threshold during normal operation because doing so changes the hysteresis of the comparator and can lead to unintentional switching of the output.
Figure 7-3 shows a mode selection timing diagram.