Philips Semiconductors
Product data
NE590
Addressable peripheral driver
2001 Aug 03
5
SWITCHING CHARACTERISTICS
VCC = 5 V; Tamb = 25 °C.
SYMBOL
PARAMETER
TO
FROM
Limits
UNIT
SYMBOL
PARAMETER
TO
FROM
Min
Typ
Max
UNIT
Propagation delay time
tPLH
Low-to-High1
Output
CE
65
150
ns
tPHL
High-to-Low1
115
230
tPLH
Low-to-High2
Output
Data
65
130
ns
tPHL
High-to-Low2
120
240
tPLH
Low-to-High3
Output
Address
100
200
ns
tPHL
High-to-Low3
130
260
tPLH
Low-to-High4
Output
CLR
65
130
ns
tPHL
High-to-Low4
Switching setup requirements
tS(H)
Chip enable
High data
210
ns
tS(L)
Chip enable
Low data
210
ns
tS(A)
Chip enable
Address
30
ns
tH(H)
Chip enable
High data
40
ns
tH(L)
Chip enable
Low data
30
ns
tPW(E)
Chip enable pulse width1
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. 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.
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.
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 is capable of output currents of 250 mA at each of its eight
outputs. It should be noted, however, that the load power dissipation
would be over 2.5 W 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 1 W, and since the power dissipation due to supply
current is 0.25 W, the total load power dissipation by the device is
limited to 0.75 W, 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:
TR = θJA × P
Tj = Tamb + TR
where
θJA is die junction to ambient thermal resistance.
PD is total power dissipation
TR is junction temperature rise above ambient
Tj is die junction temperature
Tamb 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 10 mA, we find from the graph of
output voltage versus 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 0.4 V,
respectively. Total device power due to these loads is found to be
473.5 mW. Adding the 250 mW due to the power supply brings total
device power dissipation to 723.5 mW. The thermal resistance is
83
°C per W for plastic packages. Using the equations above we
find:
TR = 83 × 0.7235 = 60 °C
Tj = 50 + 60 = 100 °C
Thus we find that Tj is below the 165 °C maximum and this package
could be used in this application. The graphs of total load power
versus ambient temperature would also give us this same
information, although interpreting the graphs would not yield the
same accuracy.