DM74LS503 [FAIRCHILD]
8-Bit Successive Approximation Register (with Expansion Control); 8位逐次逼近寄存器（带扩展控制）
| 型号： | DM74LS503 |
| 厂家： | 
FAIRCHILD SEMICONDUCTOR |
| 描述： | 8-Bit Successive Approximation Register (with Expansion Control) |
| 文件： | 总4页 (文件大小：49K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
March 1989
Revised March 2000
DM74LS503
8-Bit Successive Approximation Register
(with Expansion Control)
General Description
Features
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.
■ Performs serial-to-parallel conversion
■ Expansion control for longer words
■ Storage and control for successive approximation A to D
conversion
■ Low power Schottky version of 2503
Ordering Code:
Order Number Package Number
Package Description
DM74LS503N
N16E
16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
Connection Diagram
Logic Symbol
V
= Pin 16
CC
GND = Pin 8
Pin Descriptions
Pin Names
Description
D
Serial Data Input
S
Start Input (Active LOW)
CP
E
Clock Pulse Input (Active Rising Edge)
Conversion Enable Input (Active LOW)
Conversion Complete Output (Active LOW)
Parallel Register Outputs
CC
Q0–Q7
Q7
Complement of Q7 Output
© 2000 Fairchild Semiconductor Corporation
DS010190
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Logic Diagrams
Note: Cell logic is repeated for register stages Q5 to Q1.
Connection for Longer Word Lengths
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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.
Supply Voltage
Input Voltage
7V
7V
Operating Free Air Temperature Range
Storage Temperature Range
0°C to +70°C
−65°C to +150°C
Recommended Operating Conditions
Symbol
Parameter
Min
4.75
2
Nom
Max
Units
V
VCC
VIH
VIL
IOH
IOL
TA
Supply Voltage
5
5.25
HIGH Level Input Voltage
LOW Level Input Voltage
HIGH Level Output Voltage
LOW Level Output Current
Free Air Operating Temperature
Setup Time HIGH or LOW
S to CP
V
0.8
−0.4
8
V
mA
mA
°C
0
16
16
0
70
tS (H)
tS (L)
tH (H)
tH (L)
tS (H)
tS (L)
tH (H)
tH (L)
tW (H)
tW (L)
ns
ns
ns
ns
ns
Hold Time HIGH or LOW
S to CP
0
Setup Time HIGH or LOW
D to CP
8
8
Hold Time HIGH or LOW
D to CP
10
10
46
46
CP Pulse Width HIGH or LOW
Electrical Characteristics
Over recommended operating free air temperature range (unless otherwise noted)
Symbol Parameter Conditions
Input Clamp Voltage = Min, I = −18 mA
Typ
(Note 2)
Min
Max
Units
V
V
V
V
V
V
−1.5
V
V
I
CC
I
HIGH Level
= Min, I = Max,
OH
OH
CC
2.7
Output Voltage
= Max
IL
V
LOW Level
= Min, I = Max, V = Min
0.5
0.4
OL
CC
OL
IH
V
Output Voltage
I
= 4 mA, V = Min
OL CC
I
Input Current @ Max
Input Voltage
V
= Max, V = 7V
I
CC I
0.1
mA
V = 10V
I
I
I
I
I
HIGH Level Input Current
LOW Level Input Current
Short Circuit Output Current
Supply Current
V
V
V
V
= Max, V = 2.7V
20
−0.8
−100
65
µA
mA
mA
mA
IH
CC
CC
CC
CC
I
= Max, V = 0.4V
IL
I
= Max (Note 3)
= Max
−20
OS
CC
Note 2: All typicals are at V = 5V, T = 25°C.
CC
A
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 = +25°C
A
R
= 2 kΩ, C = 15 pF
L
L
Symbol
Parameter
Units
Min
Max
f
Maximum Count Frequency
15
MHz
ns
MAX
t
Propagation Delay
CP to Qn or CC
Propagation Delay
E to Q7
35
25
20
24
PLH
t
PHL
t
PLH
ns
t
PHL
3
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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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