24-09-2012, 02:53 PM
DECADE COUNTER/DIVIDER WITH DECODED 7-SEGMENT DISPLAY OUTPUT AND RIPPLE BLANKING
[attachment=34483]
DESCRIPTION
The HCF4033B is a monolithic integrated circuit
fabricated in Metal Oxide Semiconductor
technology available in DIP and SOP packages.
The HCF4033B consists of a 5-stages Johnson
decade counter and an output decoder which
converts the Johnson code to a 7 segment
decoded output for driving one stage in a
numerical display. This device is particularly
advantageous in display applications where low
power dissipation and/or low package count are
important. This device has CLOCK, RESET,
CLOCK INHIBIT, RIPPLE BLANKING, LAMP
TEST input, CARRY OUT, RIPPLE BLANKING
and 7 DECODED outputs (a to g).
A high RESET signal clears the decade counter to
its zero count. The counter is advanced one count
at the positive clock signal transition if the CLOCK
INHIBIT signal is low. Counter advancement via
the clock line is inhibited when the CLOCK
INHIBIT signal is high. Antilock gating is provided
on the JOHNSON counter, thus assuring proper
counting sequence. The CARRY-OUT (COUT)
signal completes one cycle every ten CLOCK
INPUT cycles and is used to clock the succeeding
decade directly in a multi-decade counting chain.
INPUT EQUIVALENT CIRCUIT
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.
[attachment=34483]
DESCRIPTION
The HCF4033B is a monolithic integrated circuit
fabricated in Metal Oxide Semiconductor
technology available in DIP and SOP packages.
The HCF4033B consists of a 5-stages Johnson
decade counter and an output decoder which
converts the Johnson code to a 7 segment
decoded output for driving one stage in a
numerical display. This device is particularly
advantageous in display applications where low
power dissipation and/or low package count are
important. This device has CLOCK, RESET,
CLOCK INHIBIT, RIPPLE BLANKING, LAMP
TEST input, CARRY OUT, RIPPLE BLANKING
and 7 DECODED outputs (a to g).
A high RESET signal clears the decade counter to
its zero count. The counter is advanced one count
at the positive clock signal transition if the CLOCK
INHIBIT signal is low. Counter advancement via
the clock line is inhibited when the CLOCK
INHIBIT signal is high. Antilock gating is provided
on the JOHNSON counter, thus assuring proper
counting sequence. The CARRY-OUT (COUT)
signal completes one cycle every ten CLOCK
INPUT cycles and is used to clock the succeeding
decade directly in a multi-decade counting chain.
INPUT EQUIVALENT CIRCUIT
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.