CPC5712

6

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R02

In the case of the detector 2 switching points, DET2

will be low after the |TIP/RING| voltage has decreased

high until after the |TIP/RING| voltage has increased

threshold of 22V. DET2 will be low if the |TIP/RING|

voltage decreases below 20V, and it will remain low

until the |TIP/RING| voltage increases above 22V.

DET2 will change states for both positive and negative

values of TIP/RING voltage as represented by

|TIP/RING|. This means that DET2 will also be low if

the TIP/RING voltage decreases below -20V and will

remain low until the TIP/RING voltage increases

beyond -22V. The user must rely on POLARITY to

determine whether the TIP/RING threshold changed

due to a positive or negative differential signal since

DET2 does not contain any polarity information.

DET1 behaves similarly to DET2, except that it is

This means that DET1 will be low after the |TIP/RING|

voltage has decreased below the value set by the

|TIP/RING| voltage has increased above the value set

information for the same reasons as defined for DET2.

In the application circuit provided, the TIP/RING

threshold levels of DET2 will always be higher than the

threshold levels of DET1.

2.5 Detector Threshold Operation

|TIP/RING| threshold levels that are to be detected.

|TIP/RING| voltage has crossed a threshold level and

when it has exceeded the configured hysteresis level.

This was explained in the DET1 and DET2 definitions.

In general, the digital output will be low when the

will change high again once the |TIP/RING| voltage

level that is applied to OUT+ and OUT-. This voltage is

brought off chip so that it can be used to define

threshold detection levels. Load capacitance on this

pin must be kept less than the value recommended in

the table Recommended Operating Conditions.

The total load resistance on this pin must be within the

range specified in the table Recommended

Operating Conditions.

Resistors R1, R2, R3, R4 and R5 are external

resistors, which must be provided by the user. The

selection of the resistors determines the voltages at

hysteresis values for the 2 detectors.

The values for R1, R2, R3, R4, and R5 are easily

threshold and hysteresis settings such that:

Then use the following algorithm to find the values of

R2, R3, R4 and R5.

1.

Select a value for R1.

2.

3.

4.

5.

typically calculates to 0.05; in this case: 0.04938.

See Figure 1.

Also, as shown in the table of Recommended

pin must fall within the range:

20k

 < (R1 + R2 + R3 + R4 + R5) < 1M

2.6 Power Connections

VCC, Ground: Power supply pins. These are used to

supply voltage and ground to the chip.