Philips PM2517E - HEF 4511 B BCD to 7-Segment Latch Decoder; Specification of ICs Used

41
3.4.
SPECIFICATION
OF
IC'S USED IN THE
PM 2517
3.4.'1.
HEF
4511 B BCD to 7-segment
latch decodet
The HEF 451
1
is a BCD to
7-segment latch/decoder/driver with four address
inputs
(A0-A3).
an active
LOW latch enable input
(ELJ,
an active LOW
ripple blanking inputTIET, an acrive LOW
lamp test input
(lTL),
and even active
HIGH
n-p-n bipolar segment outputs
(Oa
to
Og).
When E-L is LOW, the
state of the segment outputs
(Oa
to Oo)
is dete-rmined by the data
on AO to 43.
When
Et
goes
H lGH, the last data
present
on AO
ro
A3
are siored
in the latches and the segment
outputs
remain stable. When i=il is LOW,
all the segment
outputs are HIGH independent of all
other input conditions.
With ITL HIGH.
a LOW on
IB forces
allsegment outpurs
LOW. The inputs ITL and IB
do not
effect
the
latch
circu
it.
I
c
b
o
I
I
GND
I
V
Fis. 27.
address
(data)
inputs)
latch enable
input
{active
LOW)
ripple
blanking input
(active
LOW)
lamp test
input
(active
LOW)
segment outputs
L-
Fis.28.
Vss
( -8.5V
)
AO
A3
IB
IlL
A2
PINNING
AO
to
A3
'B
m
HEF 45I1
Vss
(-8.5V
)
sT2488