HCF4033B

2/11

INPUT EQUIVALENT CIRCUIT

PIN DESCRIPTION

PIN No

SYMBOL

NAME AND FUNCTION

1

CLOCK

Clock Input

10, 12, 13, 9,

11, 6, 7

a to g

7 - Segments Decoded

Outputs

2

CLOCK

INHIBIT

Clock Inhibit Input

15

RESET

Reset Input

3

RIPPLE

BLANKING

IN

Ripple Blanking Input

5

CARRY OUT Carry Out Output

4

RIPPLE

BLANKING

OUT

Ripple Blanking Output

14

LAMP TEST Lamp Test Input

8

Negative Supply Voltage

16

Positive Supply Voltage

The seven decoded outputs (a, b, c, d, e, f, g)

illuminate the proper segments in a seven

segment display device used for representing the

decimal numbers 0 to 9. The 7-segment outputs

go high on selection. This device has provisions

for automating blanking of the non-significant

zeros in a multi digit decimal number which results

in a easily readable display consistent with normal

writing

practice.

For

example,

the

number

0050.07000 in an eight digit display would be

displayed as 50.07. Zero suppression on the

integer side is obtained by connecting the RBI

terminal of the HCF4033B associated with the

most significant digit in the display to a low level

voltage and connecting the RBO terminal of that

stage to the RBI terminal of the HCF4033B in the

next lower significant position in the display. This

procedure is continued for each succeeding

HCF4033B on the integer side of the display. On

the fraction side of the display the RBI of the

HCF4033B associated with the least significant bit

is connected to a low level voltage and the RBO of

that HCF4033B is connected to the RBI terminal

of the HCF4033B in the next more significant bit

position. Again, this procedure is continued for all

HCF4033B’s on the fraction side of the display. In

a purely fractional number the zero immediately

preceding the decimal point can be displayed by

connecting the RBI of that stage to a high level

voltage (instead of to the RBO of the next more

significant stage). For example : optional zero

→

0.7346. Likewise, the zero in a number such as

763.0 can be displayed by connecting the RBI of

the HCF4033B associated with it to a high level

voltage. Ripple blanking of non-significant zeros

provides an appreciable savings in display power.

The HCF4033B has a LAMP TEST input which,

when connected to a high level voltage, overrides

normal decoder operation and enables a check to

be made on possible display malfunctions by

putting the seven outputs in the high state.