74LS04 TTL interter

[Benjamin Gearhart]

Okay, my first question of probably way too many coming soon, lol.
I know the Vcc of the 74LS04 is 5 volts, and 5.25 volts maximum recommended.
(I see that the NS-military version- is 5.5 volts max recommended, just odd
to me that the commercial standard had higher standars that the military
one..hmmmm)
I'm going to apply an input waveform to the abovementioned inverter, my
question is, what are the max positive and negative peak voltages that I
should apply? Wouldn't they just be 5.25 max?
(dumb me doesn't have a databook cause all are sold out, would that info be
in there anyway, or is this just a common sense question?)

Thanks in advance!
-Ben

 

[John Popelish]

Benjamin Gearhart wrote:

Okay, my first question of probably way too many coming soon, lol.
I know the Vcc of the 74LS04 is 5 volts, and 5.25 volts maximum recommended.
(I see that the NS-military version- is 5.5 volts max recommended, just odd
to me that the commercial standard had higher standars that the military
one..hmmmm)
I'm going to apply an input waveform to the abovementioned inverter, my
question is, what are the max positive and negative peak voltages that I
should apply? Wouldn't they just be 5.25 max?
(dumb me doesn't have a databook cause all are sold out, would that info be
in there anyway, or is this just a common sense question?)

Thanks in advance!
-Ben

The military are guaranteed over a wider range of temperatures than
the commercial ones are. I suspect the military have required chips
that work over a larger supply range, also. The manufacturers charge
a very large premium for those wide range selected units.

Almost all logic chips in the TTL and CMOS families work fine with
inputs that vary between the supply rail voltages. TTL chips go
through their logic swing as the input voltage pass through about 1.5
volts above the negative rail voltage, so it is not so important that
the input swing all the way to the positive rail. Any input above
about 2 volts definitely a log high input and is as good as any other
voltage between that and the positive supply rail at keeping the
output low. Any input below .8 volts above the negative rail is a
definite logic low.

If you want a gate that squares up an analog voltage, LSTTL may not be
the best family, since they draw continuous input current when the
input is a logic low. CMOS logic has a very high input resistance
(essentially a capacitor) so it is very handy when working with analog
inputs. There is a 4000 series like the CD4069 that has a supply
range from 3 to 18 volts. There is a high output current version, the
CD4049, and some schmitt trigger versions that switch at two levels,
one going up and a lower one going down, to prevent the output from
hovering between logic levels. An example would be CD40106.

There are several other CMOS families. The 74HCxx family is faster
than the 4000 series, but has a smaller supply range (2 to 6 volts)
with the logic threshold essentially at the half way voltage. The
74HCTxx family has the same speed and supply range as the 74HC family,
but has input threshold similar to the LS family, and the ability to
pull down with enough current to drive some LS gates (remember that
input current?). Any family that starts with the number 74 have
pinouts and active states that match the same suffix number 74LS
parts.

There are also even faster families and ones with much faster speed,
but these should get you started.

--
John Popelish

 

[John Jardine]

Benjamin Gearhart <bengearhart@hotmail.com> wrote in message
news:t4u7b.252$BM.26987@news.uswest.net...

Okay, my first question of probably way too many coming soon, lol.
I know the Vcc of the 74LS04 is 5 volts, and 5.25 volts maximum
recommended.
(I see that the NS-military version- is 5.5 volts max recommended, just
odd
to me that the commercial standard had higher standars that the military
one..hmmmm)
I'm going to apply an input waveform to the abovementioned inverter, my
question is, what are the max positive and negative peak voltages that I
should apply? Wouldn't they just be 5.25 max?
(dumb me doesn't have a databook cause all are sold out, would that info
be
in there anyway, or is this just a common sense question?)

Thanks in advance!
-Ben


To download datasheets for *any* device just try typing the number

(eg"74LS04") into Google and look at the first few links.
regards
john

 

[Keith R. Williams]

In article <t4u7b.252$BM.26987@news.uswest.net>,
bengearhart@hotmail.com says...

Okay, my first question of probably way too many coming soon, lol.
I know the Vcc of the 74LS04 is 5 volts, and 5.25 volts maximum recommended.
(I see that the NS-military version- is 5.5 volts max recommended, just odd
to me that the commercial standard had higher standars that the military
one..hmmmm)

You're looking at it backwards. The commercial part requires *tighter*
tolerances (5%) on the power supply, not looser (mil spec 10%).

I'm going to apply an input waveform to the abovementioned inverter, my
question is, what are the max positive and negative peak voltages that I
should apply? Wouldn't they just be 5.25 max?

As others have said, anything below .8C (but not below -.6v or so) and
anything above 2.0 (not to exceed Vcc+.6V) should work fine.

(dumb me doesn't have a databook cause all are sold out, would that info be
in there anyway, or is this just a common sense question?)

Look on the net. These datasheets are out there. A *quick* search
reveals: http://focus.ti.com/lit/ds/symlink/sn74ls04.pdf

--
Keith

 

[jibaro]

"Benjamin Gearhart" <bengearhart@hotmail.com> wrote in message
news:t4u7b.252$BM.26987@news.uswest.net...

Okay, my first question of probably way too many coming soon, lol.
I know the Vcc of the 74LS04 is 5 volts, and 5.25 volts maximum
recommended.
(I see that the NS-military version- is 5.5 volts max recommended, just
odd
to me that the commercial standard had higher standars that the military
one..hmmmm)

Military hardening. the part is less susceptible to damage by a simple
failure elsewhere in the circuit. the system still works albeit in degraded
mode.
there is a time and a place for higher standards....

 

[Sir Charles W. Shults III]

"jibaro" <jibaro@cfl.rr.com> wrote in message
news:sCP7b.33897$875.1408584@twister.tampabay.rr.com...

"Benjamin Gearhart" <bengearhart@hotmail.com> wrote in message
news:t4u7b.252$BM.26987@news.uswest.net...
Okay, my first question of probably way too many coming soon, lol.
I know the Vcc of the 74LS04 is 5 volts, and 5.25 volts maximum
recommended.
(I see that the NS-military version- is 5.5 volts max recommended, just
odd
to me that the commercial standard had higher standars that the military
one..hmmmm)

Military hardening. the part is less susceptible to damage by a simple
failure elsewhere in the circuit. the system still works albeit in degraded
mode.
there is a time and a place for higher standards....

You know, this is a pretty interesting misconception. Most "military" parts

are simply screened to operate at the military temperature range and any other
spec that gets thrown at them. Typically, they are not "hardened" so to speak.
They just come from the same batch of wafers and get tested to -55C / +125C and
then make sure they meet propagation delay plus perhaps a couple of other simple
specs. Those that fall out are then screened to -35C / +85C or some other
similar range and are graded as "industrial". The rest simply have to operate
at some much milder temperature range like 0C to 70C and still operate well.
Those are commercial parts.
The temperatures ranges may change a bit from vendor to vendor (for
instance, National Semiconductor would typically be -55C to +125C for
military, -40C to +85C for industrial, and 0C to +70C for commercial), but the
bottom line is - they are all the same devices.
Note that the speed figures and propagation delay figures for commercial
parts were usually the best. Well, yeah, but typically the others would run
that fast too- just not across the whole temperature range. So you see
derating, not hardening.

Cheers!

Chip Shults
My robotics, space and CGI web page - http://home.cfl.rr.com/aichip