FUNCTIONAL DESCRIPTION (cont.)

HOLT INTEGRATED CIRCUITS

6

3) Following test completion,

, the host should set the sensor outputs to

their pre-test values by writing bits CR8 - CR1 with

their corresponding Data Register pre-test values

recorded in step 2) above.

4) Normal operation (CR9 = 0) is restored by writing

the Configuration Register with its pre-test value

stored in step 1).

to be reduced

but while still in BIT

mode

INPUT THRESHOLD CHARACTERISTIC

The input threshold has some variation with the VDD supply

and with temperature. Using a temperature controlled

resistor with a positive temperature coefficient will allow the

variation over temperature

.

Below are some charts that show the typical characteristics

with a non temperature controlled resistor (NTCR) and with a

temperature controlled resistor (TCR).

When using the temperature compensated resistor

option; a 3k ohm resistor should be selected that has a

PTC (positive temperature coefficient) of 3000ppm. This

resistor will also need to meet the lightning protection

criteria for both wattage and voltage, please contact Holt

Support for guidelines on this.

RESISTOR SELECTION

HI-8428-R

Figure 8.

Input Threshold Characteristic, Spply/Open Low

Figure 9

Input Threshold Characteristic, Supply/Open High

Figure 6.

Input Threshold Characteristics, Ground/Open Low

Figure 7.

Input Threshold Characteristic, Ground/Open High