© 2000 Fairchild Semiconductor Corporation
DS009797
www.fairchildsemi.com
October 1988
Revised March 2000
DM9370 7-
Segm
ent
Dec
oder/
D
ri
ver/
Latch wit
h
Open-
Coll
ect
or O
u
tput
s
DM9370
7-Segment Decoder/Driver/Latch
with Open-Collector Outputs
General Description
The DM9370 is a 7-segment decoder driver incorporating
input latches and output circuits to directly drive incandes-
cent displays. It can also be used to drive common anode
LED displays in either a multiplexed mode or directly with
the aid of external current limiting resistors.
Ordering Code:
Connection Diagram
Logic Symbol
V
CC
=
Pin 16
GND
=
Pin 8
Pin Descriptions
Order Number
Package Number
Package Description
DM9370
N16E
16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
Pin Names
Description
A0A3
Address Inputs
LE
Latch Enable Input (Active LOW)
RBI
Ripple Blanking Input (Active LOW)
RBO
Ripple Blanking as Output (Active LOW)
as Input (Active LOW)
ag
Segment Outputs (Active LOW)
www.fairchildsemi.com
2
D
M
9370
Truth Table
*The RBI will blank the display only if binary zero is stored in the latches.
**RBO used as an input overdrives all other input conditions.
H
=
HIGH Voltage Level
L
=
LOW Voltage Level
X
=
Immaterial
Functional Description
The DM9370 has active LOW outputs capable of sinking in
excess of 25 mA which allows it to drive a wide variety of 7-
segment incandescent displays directly. It may also be
used to drive common anode LED displays, multiplexed or
directly with the aid of suitable current limiting resistors.
This device accepts a 4-bit binary code and produces out-
put drive to the appropriate segments of the 7-segment dis-
play. It has a hexadecimal decode format which produces
numeric codes "0" through "9" and alpha codes "A" through
"F" using upper and lower case fonts.
Latches on the four data inputs are controlled by an active
LOW latch enable LE. When the LE is LOW, the state of
the outputs is determined by the input data. When the LE
goes HIGH, the last data present at the inputs is stored in
the latches and the outputs remain stable. The LE pulse
width necessary to accept and store data is typically 30 ns
which allows data to be strobed into the DM9370 at normal
TTL speeds. This feature means that 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 incandescent displays with multiplexed data inputs
from MOS time clocks, DVMs, calculator chips, etc. Data
inputs are multiplexed while the displays are in static mode.
This lowers component and insertion costs since several
circuits--seven diodes per display, strobe drivers, a sepa-
rate display voltage source, and clock failure detect cir-
cuits--traditionally found in incandescent multiplexed
display systems are eliminated. It also allows low strobing
rates to be used without display flicker.
Another DM9370 feature is the reduced loading on the
data inputs when the Latch Enable is HIGH (only 10
µ
A
typ). This allows many DM9370s to be driven from a MOS
device in multiplex mode without the need for drivers on
the data lines. The DM9370 also provides automatic blank-
ing of the leading and/or trailing-edge zeroes in a multidigit
decimal number, resulting in an easily readable decimal
display conforming to normal writing practice. In an 8-digit
mixed integer fraction decimal representation, using the
automatic blanking capability, 0060.0300 would be dis-
played 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 suppres-
sion 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 provide automatic suppression of trailing-edge
zeroes. The RBO terminal of the decoder can be OR-tied
with a modulating signal via an isolating buffer to achieve
pulse duration intensity modulation. A suitable signal can
be generated for this purpose by forming a variable fre-
quency multivibrator with a cross coupled pair of TTL or
DTL gates.
3
www.fairchildsemi.com
DM9370
Numerical Designation
Logic Diagram
www.fairchildsemi.com
4
D
M
9370
Absolute Maximum Ratings
(Note 1)
Note 1: The "Absolute Maximum Ratings" are those values beyond which
the safety of the device cannot be guaranteed. The device should not be
operated at these limits. The parametric values defined in the Electrical
Characteristics tables are not guaranteed at the absolute maximum ratings.
The "Recommended Operating Conditions" table will define the conditions
for actual device operation.
Recommended Operating Conditions
Electrical Characteristics
Over recommended operating free air temperature range (unless otherwise noted)
Note 2: All typicals are at V
CC
=
5V, T
A
=
25
°
C.
Note 3: Not more than one output should be shorted at a time.
Switching Characteristics
V
CC
=
+
5.0V, T
A
=
+
25
°
C
Supply Voltage
7V
Input Voltage
5.5V
Operating Free Air Temperature Range
0
°
C to
+
70
°
C
Storage Temperature Range
-
65
°
C to
+
150
°
C
Symbol
Parameter
Min
Nom
Max
Units
V
CC
Supply Voltage
4.75
5
5.25
V
V
IH
HIGH Level Input Voltage
2
V
V
IL
LOW Level Input Voltage
0.8
V
I
OH
HIGH Level Output Current
-
80
µ
A
I
OL
LOW Level Output Current
3.2
mA
T
A
Free Air Operating Temperature
0
70
°
C
t
S
(H)
Setup Time HIGH or LOW
30
ns
t
S
(L)
A
n
to LE
20
t
H
(H)
Hold Time HIGH or LOW
0
ns
t
H
(L)
A
n
to LE
0
t
W
(L)
LE Pulse Width LOW
45
ns
Symbol
Parameter
Conditions
Min
Typ
Max
Units
(Note 2)
V
I
Input Clamp Voltage
V
CC
=
Min, I
I
=
-
12 mA
-
1.5
V
V
OH
HIGH Level
V
CC
=
Min, I
OH
=
Max
2.4
3.4
V
Output Voltage
V
IL
=
Max
V
OL
LOW
Level V
CC
=
Min, I
OL
=
Max
0.2
0.4
V
Output Voltage
V
IH
=
Min
I
I
Input Current @ Max Input Voltage
V
CC
=
Max, V
I
=
5.5V
1
mA
I
IL
LOW Level Input Current
V
CC
=
Max, V
I
=
0.4V
-
1.6
mA
I
OS
Short Circuit Output Current
V
CC
=
Max (Note 3)
-
20
-
70
mA
V
OH
Output HIGH Voltage
RBO
V
CC
=
Min, I
OH
-
80
µ
A
2.4
V
V
OL
Output LOW Voltage
RBO
I
OL
=
3.2 mA
V
CC
=
Min
0.4
V
ag
I
OL
=
25 mA
0.4
I
OH
Output HIGH Current, ag
250
µ
A
I
CC
Power Supply Current
V
CC
=
Max
105
µ
A
A
1
, A
2
, A
3
, LE
=
GND
105
mA
V
CC
=
Max, Outputs OPEN
A
0
, A
1
, A
2
, LE
=
GND
94
V
CC
=
Max, Outputs OPEN
Symbol
Parameter
C
L
=
15 PF, R
L
=
500
Units
Min
Max
t
PLH
Propagation Delay
75
ns
t
PHL
A
n
to ag
50
t
PLH
Propagation Delay
90
ns
t
PHL
LE to ag
70
5
www.fairchildsemi.com
DM9370 7-
Segm
ent
Dec
oder/
D
ri
ver/
Latch wit
h
Open-
Coll
ect
or O
u
tput
s
Physical Dimensions
inches (millimeters) unless otherwise noted
16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
Package Number N16E
Fairchild does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and
Fairchild reserves the right at any time without notice to change said circuitry and specifications.
LIFE SUPPORT POLICY
FAIRCHILD'S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT
DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD
SEMICONDUCTOR CORPORATION. As used herein:
1. Life support devices or systems are devices or systems
which, (a) are intended for surgical implant into the
body, or (b) support or sustain life, and (c) whose failure
to perform when properly used in accordance with
instructions for use provided in the labeling, can be rea-
sonably expected to result in a significant injury to the
user.
2. A critical component in any component of a life support
device or system whose failure to perform can be rea-
sonably expected to cause the failure of the life support
device or system, or to affect its safety or effectiveness.
www.fairchildsemi.com
PDF 
ZIP