TC7136/TC7136A

DS21461B-page 8

© 2002 Microchip Technology Inc.

34

(7)

used, a 1

µF capacitor is recommended, which will hold the rollover error to

0.5 count.

35

(6)

(5)

The analog input required to generate a full scale output (1999 counts). Place

100mV between Pins 35 and 36 for 199.9mV full scale. Place 1V between Pins 35

and 36 for 2V full scale. See Section 6.6, Reference Voltage.

36

(4)

TEST

Lamp test. When pulled HIGH (to V+), all segments will be turned ON and the

display should read -1888. It may also be used as a negative supply for externally

generated decimal points. See Section 7.4, Test for additional information.

37

(3)

OSC3

See Pin 40.

38

(2)

OSC2

See Pin 40.

39

(1)

OSC1

Pins 40, 39 and 38 make up the oscillator section. For a 48kHz clock

(3 readings per second), connect Pin 40 to the junction of a 180k

Ω resistor and a

50pF capacitor. The 180k

Ω resistor is tied to Pin 39 and the 50pF capacitor is tied

to Pin 38.

TABLE 2-1:

PIN DESCRIPTION (CONTINUED)

Pin Number

(40-Pin PDIP)

Normal

(Reverse)

Symbol

Description