3-245

TELCOM SEMICONDUCTOR, INC.

7

6

5

4

3

1

2

8

Figure 17.

Display Segment Assignments

The ANNUNCIATOR DRIVE output (pin 3) is a square-

wave running at the backplane frequency (100 Hz or 83.3 Hz),

with a peak-to-peak voltage equal to DGND voltage. Con-

necting an annunciator to pin 3 turns it ON; connecting it to

its backplane turns it OFF.

Figure 18.

Backplane Waveforms

BP1

BP2

BP3

LOW BATTERY

LOW BATTERY

CONTINUITY

F4, E4, DP4

A4, G4, D4

B4, C4, BC4

F3, E3, DP3

A3, G3, D3

B3, C3, MINUS

B1, C1, CONTINUITY

A1, G1, D1

F1, E1, DP1

B2, C2, LOW BATTERY

A2, G2, D2

BACKPLANE

CONNECTIONS

F2, E2, DP2

CONTINUITY

BP1

BP2

BP3

Figure 19.

Typical Display Output Waveforms

VDD

VH

VL

VDISP

VDD

VH

VL

VDISP

VDD

VH

VL

VDISP

VDD

VH

VL

VDISP

b SEGMENT

LINE

ALL OFF

a SEGMENT

ON

d, g OFF

a, g ON

d OFF

ALL ON

TC7129

4-1/2 DIGIT ANALOG-TO-DIGITAL

CONVERTER WITH ON-CHIP LCD DRIVERS