Propagation delay time
t
PLH
t
PHL
Low-to-High
1
High-to-Low
1
Output CE 65
115
150
230
507080
120
ns
t
PLH
t
PHL
Low-to-High
2
High-to-Low
2
Output Data 65
120
130
240
456570
100
ns
t
PLH
t
PHL
Low-to-High
3
High-to-Low
3
Output Address 100
130
200
260
457580
140
ns
t
PLH
t
PHL
Low-to-High
4
High-to-Low
4
Output CLR 65 130
45 140
ns
t
PLH
t
PHL
Low-to-High
1
High-to-Low
1
Output CS 407080
120
ns
Switching setup requirements
t
S(H)
Chip enable High data 210 100 ns
t
S(L)
Chip enable Low data 210 100 ns
t
S(A)
Chip enable Address 30 30 ns
t
H(H)
Chip enable High data 40 10 ns
t
H(L)
Chip enable Low data 30 10 ns
t
S(CS)
Chip enable Low chip select 100 ns
t
PW(E)
Chip enable pulse width
1
120 120 ns
NOTES:
1. See Turn-On and Turn-Off Delays, Enable to Output and Enable Pulse Width timing diagram.
2. See Turn-On and Turn-Off Delays, Data to Output timing diagram.
3. See Turn-On and Turn-Off Delays, Address to Output timing diagram.
4. See Turn-Off Delay, Clear to Output timing diagram.
5. See Setup and Hold Time, Data to Enable timing diagram.
6. See Setup Time, Address to Enable timing diagram.
FUNCTIONAL DESCRIPTION
These peripheral drivers have latched outputs which hold the input
data until cleared. The NE590 has active-Low, open-collector
outputs, while the NE591 has active-High, uncommitted (open)
emitter outputs. All outputs are cleared when power is first applied.
Addressable Latch Function
Any given output can be turned on or off by presenting the address
of the output to be set or cleared to the three address pins, by
holding the “D” input High to turn on the selected input, or by holding
it Low to turn off, holding the CLR
input High, and bringing the CE
input Low. Once an output is turned on or off, it will remain so until
addressed again, or until all outputs are cleared by bringing the
CLR
, CE, and “D” inputs Low. For NE591, CS must be brought Low
any time CE is Low if any outputs are to be changed.
Demultiplexer Operation
By bringing the CLR and CE inputs Low and the “D” input High, the
addressed output will remain on and all other outputs will be off. This
condition will remain only as long as the output is addressed. For the
NE591, the CS
input must also be Low.
High Current Outputs
The obvious advantage of these devices over the 9334 and
N74LS259 (which provide a similar function) is the fact that the
NE590 and NE591 are capable of output currents of 250mA at each
of their eight outputs. It should be noted, however, that the load
power dissipation would be over 2.5W if all 8 outputs were to carry
their full rated load current at one time. Since the total power
dissipation is limited by the package to 1W, and since the power
dissipation due to supply current is 0.25W, the total load power
dissipation by the device is limited to 0.75W, and decreases as
ambient temperature rises.
The maximum die junction temperature must be limited to 165°C,
and the temperature rise above ambient and the junction
temperature are defined as:
t
R=θJA
×P
t
J=tA+tR
where
θ
JA
is die junction to ambient thermal resistance.
P
D
is total power dissipation
t
R
is junction temperature rise above ambient
t
j
is die junction temperature
t
A
is ambient (surrounding medium) temperature
For example, if we are using the NE590 in a plastic package in an
application where the ambient temperature is never expected to rise
above 50°C, and the output current at the 8 outputs, when on, are
100, 40, 50, 200, 15, 30, 80, and 10mA, we find from the graph of
output voltage vs load current that the output voltages are expected
to be about 0.92, 0.75, 0.78, 1.04, 0.5, 0.7, 0.9, and 0.4V ,
respectively. Total device power due to these loads is found to be
473.5mW. Adding the 250mW due to the power supply brings total
device power dissipation to 723.5mW. The thermal resistances are
83°C per W for plastic packages and 100°C per W for Cerdips.
Using the equations above we find: