Hi

Most IC opamp data sheets spec max. input and output voltage with PS @
+-15 V; if I use +-22 V, do I gain more volts here?

To be specific, I'm looking at the LT 1028.

Thanks for any input
Samuel

Samuel Groner wrote:


Most IC opamp data sheets spec max. input and output voltage with PS @
+-15 V; if I use +-22 V, do I gain more volts here?

To be specific, I'm looking at the LT 1028.

It usually says so in the data sheets. Aside from the "electrical
characteristics" you have to look at the "absolute maximum ratings."
For example, the LT1028 specifies a maximum power supply voltage of
+/-22V, and a maximum input voltage of "Equal to Supply Voltage." Of
course in practice you don't want to run 22V rails because if they
drift even slightly you'll risk destroying the device. Run 20V rails
to be safe, or use 22V regulators followed by a series diode or 10-ohm
resistor (with local decoupling caps) to give yourself a little margin.

To answer your question, yes. The higher supply voltage buys you
greater headroom on the input and the output.

ulysses

Samuel Groner wrote:


Most IC opamp data sheets spec max. input and output voltage with PS @
+-15 V; if I use +-22 V, do I gain more volts here?

To be specific, I'm looking at the LT 1028.

It usually says so in the data sheets. Aside from the "electrical
characteristics" you have to look at the "absolute maximum ratings."
For example, the LT1028 specifies a maximum power supply voltage of
+/-22V, and a maximum input voltage of "Equal to Supply Voltage." Of
course in practice you don't want to run 22V rails because if they
drift even slightly you'll risk destroying the device. Run 20V rails
to be safe, or use 22V regulators followed by a series diode or 10-ohm
resistor (with local decoupling caps) to give yourself a little margin.

To answer your question, yes. The higher supply voltage buys you
greater headroom on the input and the output.

ulysses

To answer your question, yes. The higher supply voltage buys you
greater headroom on the input and the output.

Thanks!
Samuel

To answer your question, yes. The higher supply voltage buys you
greater headroom on the input and the output.

Thanks!
Samuel

Samuel Groner wrote:

Most IC opamp data sheets spec max. input and output voltage with PS @
+-15 V; if I use +-22 V, do I gain more volts here?

You mean wider output swing? Maybe, it depends on the IC.

To be specific, I'm looking at the LT 1028.

Look on the data sheet about output swing with different voltages. Since
many of the reference voltages inside are regulated, higher supply rails
may or may not be a help.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Samuel Groner wrote:

Most IC opamp data sheets spec max. input and output voltage with PS @
+-15 V; if I use +-22 V, do I gain more volts here?

You mean wider output swing? Maybe, it depends on the IC.

To be specific, I'm looking at the LT 1028.

Look on the data sheet about output swing with different voltages. Since
many of the reference voltages inside are regulated, higher supply rails
may or may not be a help.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

In article ,
Justin Ulysses Morse wrote:
Samuel Groner wrote:
Most IC opamp data sheets spec max. input and output voltage with PS @
+-15 V; if I use +-22 V, do I gain more volts here?

To be specific, I'm looking at the LT 1028.

It usually says so in the data sheets. Aside from the "electrical
characteristics" you have to look at the "absolute maximum ratings."
[snip]

All this is correct, but also look at the idling dissipation specs as
well. You need to multiply the total power supply current by the
voltage drop across the two supply leads to determine the dissipation.
This must also be kept below the absolute maximum, and you also have
to consider the load current as well.

This isn't always an issue, but with some surface mount packages, some
op amps and some circuit applications, you might need a heatsink or
extra foil on the PC board to dissipate some heat.


Regards,

Monte McGuire

In article ,
Justin Ulysses Morse wrote:
Samuel Groner wrote:
Most IC opamp data sheets spec max. input and output voltage with PS @
+-15 V; if I use +-22 V, do I gain more volts here?

To be specific, I'm looking at the LT 1028.

It usually says so in the data sheets. Aside from the "electrical
characteristics" you have to look at the "absolute maximum ratings."
[snip]

All this is correct, but also look at the idling dissipation specs as
well. You need to multiply the total power supply current by the
voltage drop across the two supply leads to determine the dissipation.
This must also be kept below the absolute maximum, and you also have
to consider the load current as well.

This isn't always an issue, but with some surface mount packages, some
op amps and some circuit applications, you might need a heatsink or
extra foil on the PC board to dissipate some heat.


Regards,

Monte McGuire

In article writes:

Most IC opamp data sheets spec max. input and output voltage with PS @
+-15 V; if I use +-22 V, do I gain more volts here?

You might get more smoke.

Most 15V op amps will take 18V, but 22 is usually too much.

Look at the spec sheet for the op amp you have in mind, and don't
exceed the maximum ratings.


--
I'm really Mike Rivers - )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

In article writes:

Most IC opamp data sheets spec max. input and output voltage with PS @
+-15 V; if I use +-22 V, do I gain more volts here?

You might get more smoke.

Most 15V op amps will take 18V, but 22 is usually too much.

Look at the spec sheet for the op amp you have in mind, and don't
exceed the maximum ratings.


--
I'm really Mike Rivers - )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

"Mike Rivers" wrote in message
news:znr1084800008k@trad...

In article
writes:

Most IC opamp data sheets spec max. input and output voltage with PS @
+-15 V; if I use +-22 V, do I gain more volts here?

You might get more smoke.

Most 15V op amps will take 18V, but 22 is usually too much.

Look at the spec sheet for the op amp you have in mind, and don't
exceed the maximum ratings.

He did look at the spec sheet; the 1028 is spec'd for +/- 22V maximum. I'd
run it closer to 21 for safety's sake, but this chip works quite nicely at
that voltage. It does run kinda hot, though, even at +/- 15V, and I'd
suggest one of those little glue-on heatsinks.

Peace,
Paul

"Mike Rivers" wrote in message
news:znr1084800008k@trad...

In article
writes:

Most IC opamp data sheets spec max. input and output voltage with PS @
+-15 V; if I use +-22 V, do I gain more volts here?

You might get more smoke.

Most 15V op amps will take 18V, but 22 is usually too much.

Look at the spec sheet for the op amp you have in mind, and don't
exceed the maximum ratings.

He did look at the spec sheet; the 1028 is spec'd for +/- 22V maximum. I'd
run it closer to 21 for safety's sake, but this chip works quite nicely at
that voltage. It does run kinda hot, though, even at +/- 15V, and I'd
suggest one of those little glue-on heatsinks.

Peace,
Paul

Most 15V op amps will take 18V, but 22 is usually too much.

Look at the spec sheet for the op amp you have in mind, and don't
exceed the maximum ratings.

The LT1028 takes 22V and no, the max. output swing with 22V is not
specified (or I just do not see it).

Samuel

Most 15V op amps will take 18V, but 22 is usually too much.

Look at the spec sheet for the op amp you have in mind, and don't
exceed the maximum ratings.

The LT1028 takes 22V and no, the max. output swing with 22V is not
specified (or I just do not see it).

Samuel

Samuel Groner wrote:

Most 15V op amps will take 18V, but 22 is usually too much.

Look at the spec sheet for the op amp you have in mind, and don't
exceed the maximum ratings.

The LT1028 takes 22V and no, the max. output swing with 22V is not
specified (or I just do not see it).

In the data sheet I have for the LT1028, in the "absolute maximum
ratings" section it says... Oh, you're right, it gives the max input
(which is equal to the rail voltages) and not the max output.

ulysses

Samuel Groner wrote:

Most 15V op amps will take 18V, but 22 is usually too much.

Look at the spec sheet for the op amp you have in mind, and don't
exceed the maximum ratings.

The LT1028 takes 22V and no, the max. output swing with 22V is not
specified (or I just do not see it).

In the data sheet I have for the LT1028, in the "absolute maximum
ratings" section it says... Oh, you're right, it gives the max input
(which is equal to the rail voltages) and not the max output.

ulysses

Paul Stamler wrote:

works quite nicely at that voltage. It does run kinda hot, though,
even at +/- 15V, and I'd suggest one of those little glue-on
heatsinks.


Yeah, but don't use a 'hot-melt' glue gun !

geoff

Paul Stamler wrote:

works quite nicely at that voltage. It does run kinda hot, though,
even at +/- 15V, and I'd suggest one of those little glue-on
heatsinks.


Yeah, but don't use a 'hot-melt' glue gun !

geoff

Paul Stamler wrote:
"Mike Rivers" wrote in message
news:znr1084800008k@trad...

In article
writes:

Most IC opamp data sheets spec max. input and output voltage with
PS @ +-15 V; if I use +-22 V, do I gain more volts here?

You might get more smoke.

Most 15V op amps will take 18V, but 22 is usually too much.

Look at the spec sheet for the op amp you have in mind, and don't
exceed the maximum ratings.

He did look at the spec sheet; the 1028 is spec'd for +/- 22V
maximum. I'd run it closer to 21 for safety's sake, but this chip
works quite nicely at that voltage. It does run kinda hot, though,
even at +/- 15V, and I'd suggest one of those little glue-on
heatsinks.

The 5532 is rated at +/- 20 volt supply
http://focus.ti.com/lit/ds/symlink/ne5532.pdf

The 5534 is rated at +/- 22 volt supply
http://focus.ti.com/lit/ds/symlink/ne5534.pdf

The OPA604 is rated at +/- 24 volt supply
http://focus.ti.com/lit/ds/symlink/opa604.pdf

Paul Stamler wrote:
"Mike Rivers" wrote in message
news:znr1084800008k@trad...

In article
writes:

Most IC opamp data sheets spec max. input and output voltage with
PS @ +-15 V; if I use +-22 V, do I gain more volts here?

You might get more smoke.

Most 15V op amps will take 18V, but 22 is usually too much.

Look at the spec sheet for the op amp you have in mind, and don't
exceed the maximum ratings.

He did look at the spec sheet; the 1028 is spec'd for +/- 22V
maximum. I'd run it closer to 21 for safety's sake, but this chip
works quite nicely at that voltage. It does run kinda hot, though,
even at +/- 15V, and I'd suggest one of those little glue-on
heatsinks.

The 5532 is rated at +/- 20 volt supply
http://focus.ti.com/lit/ds/symlink/ne5532.pdf

The 5534 is rated at +/- 22 volt supply
http://focus.ti.com/lit/ds/symlink/ne5534.pdf

The OPA604 is rated at +/- 24 volt supply
http://focus.ti.com/lit/ds/symlink/opa604.pdf

In the data sheet I have for the LT1028, in the "absolute maximum
ratings" section it says... Oh, you're right, it gives the max input
(which is equal to the rail voltages) and not the max output.

You are not saying that max. out is always equal to max. in, are you?
Samuel

In the data sheet I have for the LT1028, in the "absolute maximum
ratings" section it says... Oh, you're right, it gives the max input
(which is equal to the rail voltages) and not the max output.

You are not saying that max. out is always equal to max. in, are you?
Samuel

Samuel Groner wrote:

In the data sheet I have for the LT1028, in the "absolute maximum
ratings" section it says... Oh, you're right, it gives the max input
(which is equal to the rail voltages) and not the max output.

You are not saying that max. out is always equal to max. in, are you?
Samuel

No, I'm not saying that. I'm saying I didn't read the data sheet
closely the first time. But I do suspect that the max out should be
within a couple of diode drops of the power supply voltage in most
devices. That is to say, higher rails *should* generally give you
higher output swing to some extent.

ulysses

Samuel Groner wrote:

In the data sheet I have for the LT1028, in the "absolute maximum
ratings" section it says... Oh, you're right, it gives the max input
(which is equal to the rail voltages) and not the max output.

You are not saying that max. out is always equal to max. in, are you?
Samuel

No, I'm not saying that. I'm saying I didn't read the data sheet
closely the first time. But I do suspect that the max out should be
within a couple of diode drops of the power supply voltage in most
devices. That is to say, higher rails *should* generally give you
higher output swing to some extent.

ulysses

In article writes:

You are not saying that max. out is always equal to max. in, are you?

I don't think that's the implication. The maximum output is limited by
the power supply. If it's plus and minus 20V, the maximum peak-to-peak
voltage is 40 V, or for a symmetrical waveform, 20V in each direction.
In reality, the maximum output is a bit less than that because of the
voltage drop across the output stage.

What the spec sheet (apparently) says is that the input cannot exceed
the maximum output in either direction, positive or negative.

--
I'm really Mike Rivers )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

In article writes:

You are not saying that max. out is always equal to max. in, are you?

I don't think that's the implication. The maximum output is limited by
the power supply. If it's plus and minus 20V, the maximum peak-to-peak
voltage is 40 V, or for a symmetrical waveform, 20V in each direction.
In reality, the maximum output is a bit less than that because of the
voltage drop across the output stage.

What the spec sheet (apparently) says is that the input cannot exceed
the maximum output in either direction, positive or negative.

--
I'm really Mike Rivers )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me he double-m-eleven-double-zero at yahoo

Thanks for all replies!
Samuel

Thanks for all replies!
Samuel