MC1403BP1G データシートの表示（PDF） - ON Semiconductor

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MC1403BP1G

Low Voltage Reference

ON Semiconductor 

MC1403, B

3−1/2−Digit Voltmeter − Common Anode

Displays, Flashing Overrange

An example of a 3−1/2−digit voltmeter using the

MC14433 is shown in the circuit diagram of Figure 8. The

reference voltage for the system uses an MC1403 2.5 V

reference IC. The full scale potentiometer can calibrate for

a full scale of 199.9 mV or 1.999 V. When switching from

2.0 V to 200 mV operation, RI is also changed, as shown on

the diagram.

When using RC equal to 300 kW, the clock frequency for

the system is about 66 kHz. The resulting conversion time

is approximately 250 ms.

When the input is overrange, the display flashes on and

off. The flashing rate is one−half the conversion rate. This

is done by dividing the EOC pulse rate by 2 with 1/2

MC14013B flip−flop and blanking the display using the

blanking input of the MC14543B.

The display uses an LED display with common anode

digit lines driven with an MC14543B decoder and an

MC1413 LED driver. The MC1413 contains 7 Darlington

transistor drivers and resistors to drive the segments of the

display. The digit drive is provided by four MPS−A12

Darlington transistors operating in an emitter−follower

configuration. The MC14543B, MC14013B and LED

displays are referenced to VEE via Pin 13 of the MC14433.

This places the full power supply voltage across the display.

The current for the display may be adjusted by the value of

the segment resistors shown as 150 W in Figure 8.

+5.0 V

0.1 mF

VX

MC1403

20 k

12

3

0.1 mF 300 k

RC

+5.0 V

0.1 mF

−5.0 V

0.1 mF

+5.0 V

RI *

0.1 mF **

11 10 2 12 24

3

23

1

22

21

4

20

5

6

MC14433

13

−5.0 V

4 1 16 9

2

10

3

11

5

12

13

14

15

8 67

+5.0 V

Segment Resistors

150 W (7)

7

10

6

11

5

12

4

13

3

14

2

15

1

16

0.1 mF

7

9

8

14

15 19 18 17 16

DS1

DS2

DS3

DS4

−5.0 V

5.0 V

6

5 D SQ 1

3 C RQ 2

4

8

−5.0 V

−5.0 V

−5.0 V

Minus Sign

200 W

MPS−A12 Plus Sign

110 W

51 k

MC14013B +5.0 V

Common

Anode

LED

Display

f g edc ba

* RI = 470 kW for 2.0 V Range

RI = 27 kW for 200 mV Range

** Mylar Capacitor

9 D S Q 13

11 C R Q 12

7 10 14

−5.0 V

+5.0 V

50 mF

0.1 mF

−5.0 V

MPS−A12

(4)

Figure 8. 3−1/2−Digit Voltmeter

http://onsemi.com

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