NTE8374 NTE Electronics, Inc., NTE8374 Datasheet - Page 2

• Manufacturer Part Number: NTE8374
• Description: NTE8374, Integrated Circuit Seven Segment Latch/decoder/driver For Common Anode Led's
• Manufacturer: NTE Electronics, Inc.

Functional Description:
The NTE8374 is a 7–segment decoder/driver with latches on the address inputs and active LOW
constant current outputs to drive LEDs directly. This device accepts a 4–bit binary code and produces
output drive to the appropriate segments of the 7–segment display. It has a decode format which pro-
duces numeric codes “0” through “9” and other codes.
Latches on the four data inputs are controlled by an active LOW Latch Enable, L
the state of the outputs is determined by the input data. When L
at the inputs is stored in the latches and the outputs remain stable. The L
to accept and store data can be routed directly from high speed counters and frequency dividers into
the display without slowing down the system clock or providing intermediate data storage.
The latch/decoder combination is a simple system which drives LED displays with multiplexed data
input from MOS time clocks, DVMs, calculator chips, etc. Data inputs are multiplexed while the dis-
plays are in static mode. This lowers component and insertion costs, since several circuits–seven
resistors per display, strobe drivers, a separate display voltage source, and clock failure detect cir-
cuits–traditionally found in multiplexed display systems are eliminated. It also allos low strobing rates
to be used without display flicker.
Another NTE8374 feature is the reduced loading on the data inputs when the Latch Enable is HIGH
(only 10 A typ). This allows many NTE8374s to be driven from a MOS device in multiplex mode with-
out the need for drivers on the data lines. The NTE8374 also provides automatic blanking capability
0060.0300 would be displayed as 60.03. Leading–edge zero suppression is obtained by connecting
the Ripple Blanking Output (RBO) of a decoder to the Ripple Blanking Input (RBI) of the next lower
stage device. The most significant decoder stage should have the RBI input grounded; and since
suppression of the least significant integer zero in a number is not usually desired, the RBI input of
this decoder stage should be left open. A similar procedure for the fractional part of a display will pro-
vide automatic suppression of trailing–edge zeros. The RBO terminal of the decoder can be or tied
with a modulating signal via an isolating buffer to achieve duration intensity modulation. A suitable
signal can be generated for this purpose by forming a variable frequency multivibrator with a cross
coupled pair of TTL or DTL gates.
DC Characteristics: (T
AC Characteristics: (V
AC Operating Requirements: (V
Output Voltage, Applied (OFF)
Output LOW Current, a – g
Output HIGH Current, a – g
Power Supply Current
Propagation Delay, A
Propagation Delay, L
Setup Time HIGH or LOW, A
Hold Time HIGH or LOW, A
L
E
Pulse Width LOW
Parameter
Parameter
Parameter
E to a – g
n
to a – g
n
A
CC
n
to L
to L
= 0 to +70 C unless otherwise specified)
= +5VT
E
E
t
t
Symbol
Symbol
PLH
PLH
V
I
I
I
CC
OUT
OH
CC
OL
A
, t
, t
Symbol
PHL
PHL
t
t
t
= +25 C unless otherwise specified)
t
t
s
h
w
s
h
= +5VT
(H)
(H)
(L)
(L)
(L)
Separate LED Supply
V
V
V
C
C
CC
CC
CC
L
L
= 15pF, R
= 15pF, R
A
= Max, V
= 5V, V
= Max, V
= +25 C unless otherwise specified)
Test Conditions
Test Conditions
Test Conditions
OL
L
L
IN
OUT
= 1k
= 1k
= 3V, T
= GND, V
= 5.5V
A
= +25 C
OUT
E
goes HIGH, the last data present
= 3V
Min
Min
Min
12
75
30
85
–
–
–
–
–
0
0
E
pulse width necessary
E
Typ
Typ
Typ
. When L
–
–
–
–
–
–
–
–
–
–
–
Max
Max
Max
250
140
140
10
18
50
–
–
–
–
–
E
is LOW,
Unit
Unit
Unit
mA
mA
ns
ns
ns
ns
ns
ns
ns
V
A