Document
DM7556 DM8556 TRI-STATE Programmable Binary Counters
August 1989
DM7556 DM8556 TRI-STATE Programmable Binary Counters
General Description
These circuits are synchronous edge-sensitive fully-programmable 4-bit counters The counters feature both conventional totem-pole and TRI-STATE outputs such that when the outputs are in the high impedance mode they can be used to enter data from the bus lines In addition the clear input operates completely independent of all other inputs During the programming operation data is loaded into the flip-flops on the positive-going edge of the clock pulse To facilitate cascading of these counters the MAX COUNT output can be tied directly into the count enable input of the next counter
Features
Y Y Y Y Y
Typical clock frequency 35 MHz TRI-STATE outputs Fully independent clear Synchronous loading Cascading circuitry provided internally
Connection Diagram
Dual-In-Line Package
TL F 6588 – 1
Order Number DM7556J or DM8556N See NS Package Number J16A or N16A
Function Table
Control Inputs LOAD H H H H L H H CE X X X X H L L CLK X X L L OD L H L H L L H Reset H H L L L L L I OA L Z QA0 Z a Z I O Ports I OB I OC I OD L Z QD0 Z d Z QA L L QA0 QA0 A Active Outputs QB QC QD L L QD0 QD0 D
u u u
L L Z Z QB0 QC0 Z Z b c COUNT Z Z
L L L L QB0 QC0 QB0 QC0 B C COUNT COUNT
The I O pins are used as inputs when they are TRI-STATED and the LOAD input is Low They are outputs and active when LOAD input is High and OD is Low H e High Level (Steady State) L e Low Level (Steady State) X e Don’t Care including transitions a b c d e The level of the steady state input at inputs A B C D respectively QA0 QB0 QC0 QD0 e The level of QA QB QC QD respectively before the indicated steady state input conditions were established
TRI-STATE is a registered trademark of the National Semiconductor Corporation C1995 National Semiconductor Corporation TL F 6588 RRD-B30M105 Printed in U S A
Absolute Maximum Ratings (Note) If Military Aerospace specified devices are required please contact the National Semiconductor Sales Office Distributors for availability and specifications
Supply Voltage 7V Input Voltage 5 5V Operating Free Air Temperature Range b 55 C to a 125 C DM75 DM85 0 C to a 70 C Storage Temperature Range
b 65 C to a 150 C
Note 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’’ table are not guaranteed at the absolute maximum ratings The ‘‘Recommended Operating Conditions’’ table will define the conditions for actual device operation
Recommended Operating Conditions
Symbol VCC VIH VIL IOH IOL fCLK tW Supply Voltage High Level Input Voltage Low Level Input Voltage High Level Output Current Low Level Output Current Clock Frequency (Note 1) Pulse Width (Note 1) Clock Clear Load tCE Count Enable Time (Note 1) Setup Time High Logic Level (Note 1) Hold Time High Logic Level (Note 1) Setup Time Low Logic Level (Note 1) Hold Time Low Logic Level (Note 1) Setup Hold Data Load Data Load Data Load Data Load 0 25 20 30 30
b 10
Parameter Min 45 2
DM7556 Nom 5 Max 55 Min 4 75 2 08
b2
DM8556 Nom 5 Max 5 25
Units V V 08
b5 2
V mA mA MHz
16 25 0 25 20 30 30
b 10
16 25
ns
ns
tSETUP(1)
25 30 5
b 10
25 30 5
b 10
ns
tHOLD(1)
ns
tSETUP(0)
30 25 5
b 10 b 55
30 25 5
b 10
ns
tHOLD(0)
ns 70 C
TA
Free Air Operating Temperature
125
0
Note 1 TA e 25 C and VCC e 5V
2
Electrical Characteristics over recommended operating free air temperature range (unless otherwise noted)
Symbol VI VOH VOL II IIH IIL IOZH Parameter Input Clamp Voltage High Level Output Voltage Low Level Output Voltage Input Current Input Voltage Max Conditions VCC e Min II e b12 mA VCC e Min IOH e Max VIL e Max VIH e Min VCC e Min IOL e Max VIH e Min VIL e Max VCC e Max VI e 5 5V VCC e Max VI e 2 4V VCC e Max VI e 0 4V VCC e Max VO e 2 4V VIH e Min VIL e Max VCC e Max VO e 0 4V VIH e Min VIL e Max VCC e Max (Note 2) VCC e Max DM75 DM85
b 25 b 25
Min
Typ (Note 1)
Max
b1 5
Units V V
24 04 1 40
b1 6
V mA mA mA mA
High Level Input Current Low Level Input Current Off-State Output Current with High Level Output Voltage Applied Off-State Output Current with Low Level Output Voltage Applied Short Circuit Output Current Supply Current
40
IOZL
b 40 b 70 b 70
mA
IOS
mA mA
ICC
75
100
Note 1 All typicals are at VCC e 5V TA e 25 C Note 2 Not more than one output should be shorted at a time
Switching Characteristics at VCC e 5V and TA e 25 C (See Section 1 for Test Waveforms and Output Load)
Symbol Parameter From (Input) To (Output) RL e 400X CL e 5 pF Min fMAX tPLH tPHL tPLH tPHL tPHL tPZH tPZL tPHZ tPLZ Maximum Clock Frequency Propagation Delay Time Low to High Level Output Propagation Delay Time High to Low Level Output Propagation Delay Time Low to High Level Output Propagation Delay Time High to Low Level Output Propagation Delay Time High to Low Level .