3-181

TELCOM SEMICONDUCTOR, INC.

7

6

5

4

3

1

2

8

BAR 4

OFF

OFF

BAR 3

OFF

OFF

BAR 2

OFF

ON

BAR 1

OFF

ON

BAR 0

ON

ON

1. INPUT = 0

A. BAR MODE

BAR 4

OFF

OFF

BAR 3

OFF

OFF

BAR 2

OFF

ON

BAR 1

OFF

OFF

BAR 0

ON

OFF

1. INPUT = 0

B. DOT MODE

2. INPUT = 5%

OF FULL–SCALE

2. INPUT = 5%

OF FULL–SCALE

Figure 10. Display Option Formats

BAR Format

The TC826 power-ups in the BAR mode. BAR/DOT is

pulled high internally. This display format is similar to a

thermometer display. All bars/LCD segments, including

zero, below the bar/LCD segment equaling the input signal

level are on. A half-scale input signal, for example, would be

displayed with BAR 0 to BAR 20 on.

DOT Format

the DOT mode is selected. Only the BAR LCD segment

equaling the input signal is on. The zero segment is on for

zero input.

This mode is useful for moving cursor or ‘needle’

applications.

9V

8

TC826

12

13

OSC1

14

OSC2

0.1µf

EXTERNAL

OSCILLATOR

A. SINGLE 9V SUPPLY

TC826

B. DUAL SUPPLY

0. 1µf

13

OSCILLATOR

POWER

SUPPLY

VDD 8

12

VSS

VDD = 5V

VSS = 5V

Figure 9. External Oscillator Connection

LCD Display Format

The input signal can be displayed in two formats

(Figure 10). The BAR/DOT input (Pin 61) selects the format.

The TC826 measurement cycle operates indentically for

either mode.

TC826

A/D CONVERTER WITH

BAR GRAPH DISPLAY OUTPUT