NCV1124

http://onsemi.com

5

CIRCUIT DESCRIPTION

Figure 3 shows the part operating near the minimum input

thresholds. As the sin wave input threshold is increased, the

low side clamps become active (Figure 4). Increasing the

amplitude further (Figure 5), the high−side clamp becomes

active. These internal clamps allow for voltages up to −250 V

and 250 V on the sensor side of the setup (with R1 = R2 =

22 k) (reference the diagram page 1).

Figure 6 shows the effect using the diagnostic (DIAG)

function has on the circuit. The input threshold (negative) is

switched from a threshold of −160 mV to +160 mV when

DIAG goes from a low to a high. There is no hysteresis when

DIAG is high.

Figure 3. Minimum Threshold Operation

IN1, 200 mV/div

OUT1, 2.0 V/div

20 ms/div

Figure 4. Low−Side Clamp

IN1, 5.0 V/div

OUT1, 2.0 V/div

20 ms/div

Figure 5. Low− and High−Side Clamps

IN1, 5.0 V/div

OUT1, 2.0 V/div

20 ms/div

Figure 6. Diagnostic Operation

DIAG

5.0 V/div

20 ms/div

IN1

1.0 V/div

OUT1

5.0 V/div