2000 Fairchild Semiconductor Corporation
DS010190
www.fairchildsemi.com
March 1989
Revised March 2000
DM74LS503
8-
Bit
Succes
sive
Approxi
mati
on Reg
i
st
er
DM74LS503
8-Bit Successive Approximation Register
(with Expansion Control)
General Description
The DM74LS503 register has an active LOW Enable (E)
input that is used in cascading two or more packages for
longer word lengths. A HIGH signal on E, after a START
operation, forces Q7 HIGH and prevents the device from
accepting serial data. With the E input of an DM74LS503
connected to the CC output of a preceding (more signifi-
cant) device, the DM74LS503 will be inhibited until the pre-
ceding device is filled, causing its CC output to go LOW.
This LOW signal then enables the DM74LS503 to accept
the serial data on subsequent clocks.
Features
s
Performs serial-to-parallel conversion
s
Expansion control for longer words
s
Storage and control for successive approximation A to D
conversion
s
Low power Schottky version of 2503
Ordering Code:
Connection Diagram
Logic Symbol
V
CC
=
Pin 16
GND
=
Pin 8
Pin Descriptions
Order Number
Package Number
Package Description
DM74LS503N
N16E
16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
Pin Names
Description
D
Serial Data Input
S
Start Input (Active LOW)
CP
Clock Pulse Input (Active Rising Edge)
E
Conversion Enable Input (Active LOW)
CC
Conversion Complete Output (Active LOW)
Q0Q7
Parallel Register Outputs
Q7
Complement of Q7 Output
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2
DM74LS503
Logic Diagrams
Note: Cell logic is repeated for register stages Q5 to Q1.
Connection for Longer Word Lengths
3
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DM74LS503
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, and the duration should not exceed one second.
Switching Characteristics
V
CC
=
+
5.0V, T
A
=
+
25
C
Supply Voltage
7V
Input Voltage
7V
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 Voltage
-
0.4
mA
I
OL
LOW Level Output Current
8
mA
T
A
Free Air Operating Temperature
0
70
C
t
S
(H)
Setup Time HIGH or LOW
16
ns
t
S
(L)
S to CP
16
t
H
(H)
Hold Time HIGH or LOW
0
ns
t
H
(L)
S to CP
0
t
S
(H)
Setup Time HIGH or LOW
8
ns
t
S
(L)
D to CP
8
t
H
(H)
Hold Time HIGH or LOW
10
ns
t
H
(L)
D to CP
10
t
W
(H)
CP Pulse Width HIGH or LOW
46
ns
t
W
(L)
46
Symbol
Parameter
Conditions
Min
Typ
Max
Units
(Note 2)
V
I
Input Clamp Voltage
V
CC
=
Min, I
I
=
-
18 mA
-
1.5
V
V
OH
HIGH Level
V
CC
=
Min, I
OH
=
Max,
2.7
V
Output Voltage
V
IL
=
Max
V
OL
LOW
Level V
CC
=
Min, I
OL
=
Max, V
IH
=
Min
0.5
V
Output Voltage
I
OL
=
4 mA, V
CC
=
Min
0.4
I
I
Input Current @ Max
V
CC
=
Max, V
I
=
7V
0.1
mA
Input Voltage
V
I
=
10V
I
IH
HIGH Level Input Current
V
CC
=
Max, V
I
=
2.7V
20
A
I
IL
LOW Level Input Current
V
CC
=
Max, V
I
=
0.4V
-
0.8
mA
I
OS
Short Circuit Output Current
V
CC
=
Max (Note 3)
-
20
-
100
mA
I
CC
Supply Current
V
CC
=
Max
65
mA
Symbol
Parameter
R
L
=
2 k
, C
L
=
15 pF
Units
Min
Max
f
MAX
Maximum Count Frequency
15
MHz
t
PLH
Propagation Delay
35
ns
t
PHL
CP to Qn or CC
25
t
PLH
Propagation Delay
20
ns
t
PHL
E to Q7
24
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4
DM
7
4LS503 8-Bi
t Successi
ve
Appr
oximat
i
on Regis
t
er
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.
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