Quick ESR answer needed...

Typical 0.22uF ceramic in low voltage application (5V max), what ESR
might I expect?

Client says 0.2 Ohms

I doubt that number, but don't have anything to base my doubt on.

What say yee all?

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

America: Land of the Free, Because of the Brave

Jim Thompson wrote:
Quick ESR answer needed...

Typical 0.22uF ceramic in low voltage application (5V max), what ESR
might I expect?

Client says 0.2 Ohms

I doubt that number, but don't have anything to base my doubt on.

What say yee all?

Ceramic, I say in the 10m to 50m range.


--
Kevin Aylward

Jim Thompson wrote:

Quick ESR answer needed...

Typical 0.22uF ceramic in low voltage application (5V max), what ESR
might I expect?

Client says 0.2 Ohms

I doubt that number, but don't have anything to base my doubt on.

What say yee all?


Much lower IME, more in the range Kevin gave but it depends on the
frequency. I guess your client would want a somewhat more "official"
story about it, so here goes (the MLC versus Tantalum shoot-out):

http://www.avxcorp.com/docs/techinfo/mlc-tant.pdf

Ahem, you wouldn't think about counting on the ESR for a loop design,
would ya? No, can't be ....

--
Regards, Joerg

http://www.analogconsultants.com

On Tue, 14 Aug 2007 10:41:32 -0700, Joerg
wrote:

Jim Thompson wrote:

Quick ESR answer needed...

Typical 0.22uF ceramic in low voltage application (5V max), what ESR
might I expect?

Client says 0.2 Ohms

I doubt that number, but don't have anything to base my doubt on.

What say yee all?


Much lower IME, more in the range Kevin gave but it depends on the
frequency. I guess your client would want a somewhat more "official"
story about it, so here goes (the MLC versus Tantalum shoot-out):

http://www.avxcorp.com/docs/techinfo/mlc-tant.pdf

Ahem, you wouldn't think about counting on the ESR for a loop design,
would ya? No, can't be ....

Bet he's designing a chip with built-in LDO!

I like the National AnyCap idea, an internal dominant pole that's
merely increased by external capacitance, not cascaded with it.
Basically, it's Miller capacitance off the output pin.

John

John Larkin wrote:

On Tue, 14 Aug 2007 10:41:32 -0700, Joerg
wrote:


Jim Thompson wrote:


Quick ESR answer needed...

Typical 0.22uF ceramic in low voltage application (5V max), what ESR
might I expect?

Client says 0.2 Ohms

I doubt that number, but don't have anything to base my doubt on.

What say yee all?


Much lower IME, more in the range Kevin gave but it depends on the
frequency. I guess your client would want a somewhat more "official"
story about it, so here goes (the MLC versus Tantalum shoot-out):

http://www.avxcorp.com/docs/techinfo/mlc-tant.pdf

Ahem, you wouldn't think about counting on the ESR for a loop design,
would ya? No, can't be ....


Bet he's designing a chip with built-in LDO!


Sounds like as much fun as repairing a dry-rot problem.


I like the National AnyCap idea, an internal dominant pole that's
merely increased by external capacitance, not cascaded with it.
Basically, it's Miller capacitance off the output pin.


I think that's Analog Devices. Anyhow, yes, you can buy good LDOs but
for the privilege of having one that doesn't throw the occasional
tantrum you have to pay extra. "Oh, you want a car that doesn't have a
wobble at 65mph? Ok, but it'll cost ya."

As far as I am concerned I avoid LDOs like the plague.

--
Regards, Joerg

http://www.analogconsultants.com

On Tue, 14 Aug 2007 11:39:34 -0700, Joerg
wrote:

John Larkin wrote:

On Tue, 14 Aug 2007 10:41:32 -0700, Joerg
wrote:


Jim Thompson wrote:


Quick ESR answer needed...

Typical 0.22uF ceramic in low voltage application (5V max), what ESR
might I expect?

Client says 0.2 Ohms

I doubt that number, but don't have anything to base my doubt on.

What say yee all?


Much lower IME, more in the range Kevin gave but it depends on the
frequency. I guess your client would want a somewhat more "official"
story about it, so here goes (the MLC versus Tantalum shoot-out):

http://www.avxcorp.com/docs/techinfo/mlc-tant.pdf

Ahem, you wouldn't think about counting on the ESR for a loop design,
would ya? No, can't be ....


Bet he's designing a chip with built-in LDO!


Sounds like as much fun as repairing a dry-rot problem.


I like the National AnyCap idea, an internal dominant pole that's
merely increased by external capacitance, not cascaded with it.
Basically, it's Miller capacitance off the output pin.


I think that's Analog Devices.

Yeah, I was thinking of the National C-load opamps, like the LM8261.

John

On Tue, 14 Aug 2007 11:27:24 -0700, John Larkin
wrote:

On Tue, 14 Aug 2007 10:41:32 -0700, Joerg
wrote:

Jim Thompson wrote:

Quick ESR answer needed...

Typical 0.22uF ceramic in low voltage application (5V max), what ESR
might I expect?

Client says 0.2 Ohms

I doubt that number, but don't have anything to base my doubt on.

What say yee all?


Much lower IME, more in the range Kevin gave but it depends on the
frequency. I guess your client would want a somewhat more "official"
story about it, so here goes (the MLC versus Tantalum shoot-out):

http://www.avxcorp.com/docs/techinfo/mlc-tant.pdf

Ahem, you wouldn't think about counting on the ESR for a loop design,
would ya? No, can't be ....

Bet he's designing a chip with built-in LDO!

Nope. Dumping said capacitor into a 1.5 Ohm load using a PMOS/NMOS
totem pole that uses up 1/3 of the chip :-(


I like the National AnyCap idea, an internal dominant pole that's
merely increased by external capacitance, not cascaded with it.
Basically, it's Miller capacitance off the output pin.

John



...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

America: Land of the Free, Because of the Brave

Jim Thompson wrote:

On Tue, 14 Aug 2007 11:27:24 -0700, John Larkin
wrote:


On Tue, 14 Aug 2007 10:41:32 -0700, Joerg
wrote:


Jim Thompson wrote:


Quick ESR answer needed...

Typical 0.22uF ceramic in low voltage application (5V max), what ESR
might I expect?

Client says 0.2 Ohms

I doubt that number, but don't have anything to base my doubt on.

What say yee all?


Much lower IME, more in the range Kevin gave but it depends on the
frequency. I guess your client would want a somewhat more "official"
story about it, so here goes (the MLC versus Tantalum shoot-out):

http://www.avxcorp.com/docs/techinfo/mlc-tant.pdf

Ahem, you wouldn't think about counting on the ESR for a loop design,
would ya? No, can't be ....

Bet he's designing a chip with built-in LDO!


Nope. Dumping said capacitor into a 1.5 Ohm load using a PMOS/NMOS
totem pole that uses up 1/3 of the chip :-(


Hopefully this one can run on a cheap process then.



I like the National AnyCap idea, an internal dominant pole that's
merely increased by external capacitance, not cascaded with it.
Basically, it's Miller capacitance off the output pin.


--
Regards, Joerg

http://www.analogconsultants.com

On Tue, 14 Aug 2007 09:51:38 -0700, Jim Thompson
wrote:

Quick ESR answer needed...

Typical 0.22uF ceramic in low voltage application (5V max), what ESR
might I expect?

Client says 0.2 Ohms

I doubt that number, but don't have anything to base my doubt on.

What say yee all?

...Jim Thompson

Sounds about right for a Z5U dielectric low volt cap. These things are the pits.
Terrible temp and voltage curves with lots of microphonics and absorbtion. All
they are 'good' for is power filtering at the vcc terminals of ICs.

Lynn Richardson wrote:
On Tue, 14 Aug 2007 09:51:38 -0700, Jim Thompson
wrote:

Quick ESR answer needed...

Typical 0.22uF ceramic in low voltage application (5V max), what ESR
might I expect?

Client says 0.2 Ohms

I doubt that number, but don't have anything to base my doubt on.

What say yee all?

...Jim Thompson

Sounds about right for a Z5U dielectric low volt cap. These things are the pits.
Terrible temp and voltage curves with lots of microphonics and absorbtion. All
they are 'good' for is power filtering at the vcc terminals of ICs.


With ESRs like that, they aren't even good for that.

Cheers

PeteS

Jim Thompson wrote:
Quick ESR answer needed...

Typical 0.22uF ceramic in low voltage application (5V max), what ESR
might I expect?

Client says 0.2 Ohms

I doubt that number, but don't have anything to base my doubt on.

What say yee all?

...Jim Thompson
About a hundredth of that.

2 milliohm is reasonable provided the device is rated at 10V. If it's
rated at 6V, then figure about 10 milliohm.

Cheers

PeteS

"PeteS" wrote in message
...
Jim Thompson wrote:
Quick ESR answer needed...

Typical 0.22uF ceramic in low voltage application (5V max), what ESR
might I expect?

Client says 0.2 Ohms

I doubt that number, but don't have anything to base my doubt on.

What say yee all?

...Jim Thompson
About a hundredth of that.

2 milliohm is reasonable provided the device is rated at 10V. If it's
rated at 6V, then figure about 10 milliohm.

Cheers

PeteS

Just measured one to hand.
100nF, Y5V, 25kHz, 5ohm.
1kHz 55ohm.
(for comparison, a 100nF poly' gave 8ohm at 1kHz)

Looks like I always end up at the cheap tat end of the market

john jardine wrote:
"PeteS" wrote in message
...
Jim Thompson wrote:
Quick ESR answer needed...

Typical 0.22uF ceramic in low voltage application (5V max), what ESR
might I expect?

Client says 0.2 Ohms

I doubt that number, but don't have anything to base my doubt on.

What say yee all?

...Jim Thompson
About a hundredth of that.

2 milliohm is reasonable provided the device is rated at 10V. If it's
rated at 6V, then figure about 10 milliohm.

Cheers

PeteS

Just measured one to hand.
100nF, Y5V, 25kHz, 5ohm.
1kHz 55ohm.
(for comparison, a 100nF poly' gave 8ohm at 1kHz)

Looks like I always end up at the cheap tat end of the market





Well, I don't use anything worse than X7R right now which is where I get
my numbers from. The cheaper stuff will always have worse numbers, of
course

Cheers

PeteS

On Tue, 14 Aug 2007 20:46:03 +0100, "john jardine"
wrote:


"PeteS" wrote in message
.. .
Jim Thompson wrote:
Quick ESR answer needed...

Typical 0.22uF ceramic in low voltage application (5V max), what ESR
might I expect?

Client says 0.2 Ohms

I doubt that number, but don't have anything to base my doubt on.

What say yee all?

...Jim Thompson
About a hundredth of that.

2 milliohm is reasonable provided the device is rated at 10V. If it's
rated at 6V, then figure about 10 milliohm.

Cheers

PeteS

Just measured one to hand.
100nF, Y5V, 25kHz, 5ohm.
1kHz 55ohm.
(for comparison, a 100nF poly' gave 8ohm at 1kHz)


Those numbers seem extreme, high by 2 or 3 orders of magnitude. How
did you measure them?

John

"John Larkin"
"john jardine"


Just measured one to hand.
100nF, Y5V, 25kHz, 5ohm.
1kHz 55ohm.
(for comparison, a 100nF poly' gave 8ohm at 1kHz)


Those numbers seem extreme, high by 2 or 3 orders of magnitude. How
did you measure them?


** With one of these maybe ?

http://www.m3electronix.com/featureslcr.html

Told us he owned one back on July 17.

God knows how he got those mad results.




........ Phil

"John Larkin" wrote in message
...
On Tue, 14 Aug 2007 20:46:03 +0100, "john jardine"
wrote:


"PeteS" wrote in message
.. .
Jim Thompson wrote:
Quick ESR answer needed...

Typical 0.22uF ceramic in low voltage application (5V max), what ESR
might I expect?

Client says 0.2 Ohms

I doubt that number, but don't have anything to base my doubt on.

What say yee all?

...Jim Thompson
About a hundredth of that.

2 milliohm is reasonable provided the device is rated at 10V. If it's
rated at 6V, then figure about 10 milliohm.

Cheers

PeteS

Just measured one to hand.
100nF, Y5V, 25kHz, 5ohm.
1kHz 55ohm.
(for comparison, a 100nF poly' gave 8ohm at 1kHz)


Those numbers seem extreme, high by 2 or 3 orders of magnitude. How
did you measure them?

John


Measured on a bit of kit I bought last week.
http://www.mwinstruments.com/MW1008/MW1008_f.html
Cheap but very handy. It measures the component impedance and VI phase
displacement. All other secondary components such as LCR are then derived
mathematically.
Just for comparison I checked a part I can trace. It's a 470n open frame
Polyester, EPCOS part #B32560J1474K. The data sheet states a loss factor of
0.008 at 1kHz.
The meter (test at 1kHz) shows D=0.0046, L=475.6nF, Series R=1.55ohms.
The values tie up nicely.

(Had assumed most people would be equipped with fancy HP analyzers and would
have posted a measurement or two but haven't see anything come in yet.)

On Wed, 15 Aug 2007 01:21:23 +0100, "john jardine"
wrote:


"John Larkin" wrote in message
.. .
On Tue, 14 Aug 2007 20:46:03 +0100, "john jardine"
wrote:


"PeteS" wrote in message
.. .
Jim Thompson wrote:
Quick ESR answer needed...

Typical 0.22uF ceramic in low voltage application (5V max), what ESR
might I expect?

Client says 0.2 Ohms

I doubt that number, but don't have anything to base my doubt on.

What say yee all?

...Jim Thompson
About a hundredth of that.

2 milliohm is reasonable provided the device is rated at 10V. If it's
rated at 6V, then figure about 10 milliohm.

Cheers

PeteS

Just measured one to hand.
100nF, Y5V, 25kHz, 5ohm.
1kHz 55ohm.
(for comparison, a 100nF poly' gave 8ohm at 1kHz)


Those numbers seem extreme, high by 2 or 3 orders of magnitude. How
did you measure them?

John


Measured on a bit of kit I bought last week.
http://www.mwinstruments.com/MW1008/MW1008_f.html
Cheap but very handy. It measures the component impedance and VI phase
displacement. All other secondary components such as LCR are then derived
mathematically.
Just for comparison I checked a part I can trace. It's a 470n open frame
Polyester, EPCOS part #B32560J1474K. The data sheet states a loss factor of
0.008 at 1kHz.
The meter (test at 1kHz) shows D=0.0046, L=475.6nF, Series R=1.55ohms.
The values tie up nicely.

(Had assumed most people would be equipped with fancy HP analyzers and would
have posted a measurement or two but haven't see anything come in yet.)




All those numbers sound very weird to me. And you can't calculate ESR
from a single-frequency vector impedance measurement. The polyester
loss is most likely dielectric absorption, which does not translate to
esr.

I just measured an axial-lead 0.1 uF ceramic cap directly, by applying
a current pulse and observing the voltage waveform. It's showing about
50 milliohms, but that's close to my resolution limit.


John

"john jardine"

Just for comparison I checked a part I can trace. It's a 470n open frame
Polyester, EPCOS part #B32560J1474K. The data sheet states a loss factor
of
0.008 at 1kHz.
The meter (test at 1kHz) shows D=0.0046, L=475.6nF, Series R=1.55ohms.
The values tie up nicely.



** The published data for that same cap shows it has an impedance minimum at
just over 3 MHz of 33 milliohms.





......... Phil

On Tue, 14 Aug 2007 09:51:38 -0700, Jim Thompson
wrote:

Quick ESR answer needed...

Typical 0.22uF ceramic in low voltage application (5V max), what ESR
might I expect?

At what frequency? That makes a big difference.


Client says 0.2 Ohms

I doubt that number, but don't have anything to base my doubt on.

What say yee all?

...Jim Thompson

"The Phantom"
Jim Thompson


Typical 0.22uF ceramic in low voltage application (5V max), what ESR
might I expect?

At what frequency? That makes a big difference.


** Not to the minimum impedance the cap can exhibit - which is the series
resistance that counts for supply bypass and filtering applications.

No one is too bothered about di-electric losses for that as they only help !



........ Phil

On Tue, 14 Aug 2007 23:42:47 -0700, The Phantom
wrote:

On Tue, 14 Aug 2007 09:51:38 -0700, Jim Thompson
wrote:

Quick ESR answer needed...

Typical 0.22uF ceramic in low voltage application (5V max), what ESR
might I expect?

At what frequency? That makes a big difference.


Client says 0.2 Ohms

I doubt that number, but don't have anything to base my doubt on.

What say yee all?

...Jim Thompson

If frequency makes a difference then isn't it "ESL" rather than ESR?

Application has capacitor charged to +1.8V, it is then connected (4ns
full-on connect time) thru a 1.5 Ohm "strap" to -1.8V.

In other words, over 2A peak current.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

America: Land of the Free, Because of the Brave

On Wed, 15 Aug 2007 07:11:54 -0700, Jim Thompson
wrote:

On Tue, 14 Aug 2007 23:42:47 -0700, The Phantom
wrote:

On Tue, 14 Aug 2007 09:51:38 -0700, Jim Thompson
wrote:

Quick ESR answer needed...

Typical 0.22uF ceramic in low voltage application (5V max), what ESR
might I expect?

At what frequency? That makes a big difference.


Client says 0.2 Ohms

I doubt that number, but don't have anything to base my doubt on.

What say yee all?

...Jim Thompson

If frequency makes a difference then isn't it "ESL" rather than ESR?

ESR (with the meaning as used by the capacitor manufacturers) does vary
with frequency. See: http://www.avxcorp.com/docs/techinfo/mlc-tant.pdf

Of course, capacitors have an ESL as well as an ESR (the E stands for
Equivalent, which means a simple model), and the *impedance* of the
capacitor is dominated by ESL above the series resonant frequency.

The Kemet folks show the impedance vs. frequency characteristic for their
various MLC's in this file:
http://www.kemet.com/kemet/web/homepage/kechome.nsf/weben/B3D6942FD742E4A5CA2570A500160908/$file/F3102_CerPerChar.pdf

Given the short connect time, 4ns, of your application it looks like you
will care about the (typical) capacitor's impedance well above series
resonance, which will probably be dominated by ESL. You might want to use
a COG dielectric.


Application has capacitor charged to +1.8V, it is then connected (4ns
full-on connect time) thru a 1.5 Ohm "strap" to -1.8V.

In other words, over 2A peak current.

...Jim Thompson

On Wed, 15 Aug 2007 07:11:54 -0700, Jim Thompson
wrote:

On Tue, 14 Aug 2007 23:42:47 -0700, The Phantom
wrote:

On Tue, 14 Aug 2007 09:51:38 -0700, Jim Thompson
wrote:

Quick ESR answer needed...

Typical 0.22uF ceramic in low voltage application (5V max), what ESR
might I expect?

At what frequency? That makes a big difference.


Client says 0.2 Ohms

I doubt that number, but don't have anything to base my doubt on.

What say yee all?

...Jim Thompson

If frequency makes a difference then isn't it "ESL" rather than ESR?

Application has capacitor charged to +1.8V, it is then connected (4ns
full-on connect time) thru a 1.5 Ohm "strap" to -1.8V.

In other words, over 2A peak current.

...Jim Thompson

Tricky. Assuming a 1 ns risetime, 4 volts available, only 2 nH or so
will get you into trouble. A cap and its leads will get you to about 2
nH, then there's all your wirebonds, not to mention the load itself.

We usually parallel several caps, on a lot of copper, to supply a lot
of fast peak current, like through a gaasfet to drive an SRD or a
laser.

(Gotta get ready for a Board meeting. What a nuisance.)


John

On Wed, 15 Aug 2007 08:38:09 -0700, John Larkin
wrote:

On Wed, 15 Aug 2007 07:11:54 -0700, Jim Thompson
wrote:

On Tue, 14 Aug 2007 23:42:47 -0700, The Phantom
wrote:

On Tue, 14 Aug 2007 09:51:38 -0700, Jim Thompson
wrote:

Quick ESR answer needed...

Typical 0.22uF ceramic in low voltage application (5V max), what ESR
might I expect?

At what frequency? That makes a big difference.


Client says 0.2 Ohms

I doubt that number, but don't have anything to base my doubt on.

What say yee all?

...Jim Thompson

If frequency makes a difference then isn't it "ESL" rather than ESR?

Application has capacitor charged to +1.8V, it is then connected (4ns
full-on connect time) thru a 1.5 Ohm "strap" to -1.8V.

In other words, over 2A peak current.

...Jim Thompson

Tricky. Assuming a 1 ns risetime, 4 volts available, only 2 nH or so
will get you into trouble. A cap and its leads will get you to about 2
nH, then there's all your wirebonds, not to mention the load itself.

Face-down ball bonded. ~0.5nH connections.


We usually parallel several caps, on a lot of copper, to supply a lot
of fast peak current, like through a gaasfet to drive an SRD or a
laser.

(Gotta get ready for a Board meeting. What a nuisance.)


John

Me, my wife and my oldest daughter ARE the board... no nuisance ;-)

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

America: Land of the Free, Because of the Brave

Jim Thompson wrote:

On Wed, 15 Aug 2007 08:38:09 -0700, John Larkin
wrote:


On Wed, 15 Aug 2007 07:11:54 -0700, Jim Thompson
wrote:


On Tue, 14 Aug 2007 23:42:47 -0700, The Phantom
wrote:


On Tue, 14 Aug 2007 09:51:38 -0700, Jim Thompson
wrote:


Quick ESR answer needed...

Typical 0.22uF ceramic in low voltage application (5V max), what ESR
might I expect?

At what frequency? That makes a big difference.


Client says 0.2 Ohms

I doubt that number, but don't have anything to base my doubt on.

What say yee all?

...Jim Thompson

If frequency makes a difference then isn't it "ESL" rather than ESR?

Application has capacitor charged to +1.8V, it is then connected (4ns
full-on connect time) thru a 1.5 Ohm "strap" to -1.8V.

In other words, over 2A peak current.

...Jim Thompson

Tricky. Assuming a 1 ns risetime, 4 volts available, only 2 nH or so
will get you into trouble. A cap and its leads will get you to about 2
nH, then there's all your wirebonds, not to mention the load itself.


Face-down ball bonded. ~0.5nH connections.


We usually parallel several caps, on a lot of copper, to supply a lot
of fast peak current, like through a gaasfet to drive an SRD or a
laser.

(Gotta get ready for a Board meeting. What a nuisance.)


John


Me, my wife and my oldest daughter ARE the board... no nuisance ;-)


Same here, but no daughter.

--
Regards, Joerg

http://www.analogconsultants.com

On Wed, 15 Aug 2007 08:50:38 -0700, Jim Thompson
wrote:

On Wed, 15 Aug 2007 08:38:09 -0700, John Larkin
wrote:

On Wed, 15 Aug 2007 07:11:54 -0700, Jim Thompson
wrote:

On Tue, 14 Aug 2007 23:42:47 -0700, The Phantom
wrote:

On Tue, 14 Aug 2007 09:51:38 -0700, Jim Thompson
wrote:

Quick ESR answer needed...

Typical 0.22uF ceramic in low voltage application (5V max), what ESR
might I expect?

At what frequency? That makes a big difference.


Client says 0.2 Ohms

I doubt that number, but don't have anything to base my doubt on.

What say yee all?

...Jim Thompson

If frequency makes a difference then isn't it "ESL" rather than ESR?

Application has capacitor charged to +1.8V, it is then connected (4ns
full-on connect time) thru a 1.5 Ohm "strap" to -1.8V.

In other words, over 2A peak current.

...Jim Thompson

Tricky. Assuming a 1 ns risetime, 4 volts available, only 2 nH or so
will get you into trouble. A cap and its leads will get you to about 2
nH, then there's all your wirebonds, not to mention the load itself.

Face-down ball bonded. ~0.5nH connections.


We usually parallel several caps, on a lot of copper, to supply a lot
of fast peak current, like through a gaasfet to drive an SRD or a
laser.

(Gotta get ready for a Board meeting. What a nuisance.)


John

Me, my wife and my oldest daughter ARE the board... no nuisance ;-)

...Jim Thompson

I wasn't bad: Plant tour, 10 minutes; shareholders' meeting, 5
minutes; board meeting, 35 minutes; lunch at Zuni Cafe, 1 hour.

Chairman John

John,

A bit off this topic, I saw a post where you talk about 11801 ("When you
start getting powerup timebase errors, which you will, call
me.") I have an 11801 that has this problem. Would you be able to help me
fix it?

Thank you,
Leo

"John Larkin" wrote in message
...
On Wed, 15 Aug 2007 07:11:54 -0700, Jim Thompson
wrote:

On Tue, 14 Aug 2007 23:42:47 -0700, The Phantom
wrote:

On Tue, 14 Aug 2007 09:51:38 -0700, Jim Thompson
wrote:

Quick ESR answer needed...

Typical 0.22uF ceramic in low voltage application (5V max), what ESR
might I expect?

At what frequency? That makes a big difference.


Client says 0.2 Ohms

I doubt that number, but don't have anything to base my doubt on.

What say yee all?

...Jim Thompson

If frequency makes a difference then isn't it "ESL" rather than ESR?

Application has capacitor charged to +1.8V, it is then connected (4ns
full-on connect time) thru a 1.5 Ohm "strap" to -1.8V.

In other words, over 2A peak current.

...Jim Thompson

Tricky. Assuming a 1 ns risetime, 4 volts available, only 2 nH or so
will get you into trouble. A cap and its leads will get you to about 2
nH, then there's all your wirebonds, not to mention the load itself.

We usually parallel several caps, on a lot of copper, to supply a lot
of fast peak current, like through a gaasfet to drive an SRD or a
laser.

(Gotta get ready for a Board meeting. What a nuisance.)


John

On Wed, 15 Aug 2007 15:00:47 -0400, "Leo" wrote:

John,

A bit off this topic, I saw a post where you talk about 11801 ("When you
start getting powerup timebase errors, which you will, call
me.") I have an 11801 that has this problem. Would you be able to help me
fix it?

Thank you,
Leo

If you email me privately, I'll tell you what it probably is and how
to fix it. But promise me you won't spread it around publicly... I
just got a dead 11801A on ebay for $300, and if everybody learns this
trick, they'll all go back up to $3K.

What sort of sampling heads do you have?

John

On Tue, 14 Aug 2007 09:51:38 -0700, Jim Thompson
wrote:

Quick ESR answer needed...

Typical 0.22uF ceramic in low voltage application (5V max), what ESR
might I expect?

Client says 0.2 Ohms

I doubt that number, but don't have anything to base my doubt on.

What say yee all?



While I was waiting for The Board to show up, I cobbled up this:

http://s2.supload.com/free/Setup.JPG/view/

http://s2.supload.com/free/Ramp.JPG/view/


It's a 0.1 uF, 0805 cap soldered across a 50 ohm transmission line.
It's being driven from (we pause for this commercial message...)

http://www.highlandtechnology.com/DSS/P400DS.html

which is setup for 5 volts out, 50 ohms, so it's dumping a 100 mA step
into the cap with about a 1 ns risetime. The scope bandwidth is 20
GHz.

The first glitch is L di/dt, roughly estimated as 1.5 nH.
Extrapolating the slope back to the start gives very roughly 20
milliohms, but it's hard to resolve that small a resistance with this
rig. The glitch at about 10 ns is a cable reflection.

This cap is pretty much a dead short in the, say, 3 ns time frame.


John

On Wed, 15 Aug 2007 14:58:47 -0700, John Larkin
wrote:

On Tue, 14 Aug 2007 09:51:38 -0700, Jim Thompson
wrote:

Quick ESR answer needed...

Typical 0.22uF ceramic in low voltage application (5V max), what ESR
might I expect?

Client says 0.2 Ohms

I doubt that number, but don't have anything to base my doubt on.

What say yee all?



While I was waiting for The Board to show up, I cobbled up this:

http://s2.supload.com/free/Setup.JPG/view/

http://s2.supload.com/free/Ramp.JPG/view/


It's a 0.1 uF, 0805 cap soldered across a 50 ohm transmission line.
It's being driven from (we pause for this commercial message...)

http://www.highlandtechnology.com/DSS/P400DS.html

which is setup for 5 volts out, 50 ohms, so it's dumping a 100 mA step
into the cap with about a 1 ns risetime. The scope bandwidth is 20
GHz.

The first glitch is L di/dt, roughly estimated as 1.5 nH.
Extrapolating the slope back to the start gives very roughly 20
milliohms

A detailed description of this technique is to be found at:

http://emcesd.com/tt020100.htm

, but it's hard to resolve that small a resistance with this
rig. The glitch at about 10 ns is a cable reflection.

This cap is pretty much a dead short in the, say, 3 ns time frame.


John

"The Phantom" wrote in message
...
http://emcesd.com/tt020100.htm

Thanks for the link, Phantom.

John -- since you're not exactly enamored with Howard Johnson, do you have an
opinion on Doug Smith there? I met him once and he seems to be considerably
more "hands on" than Howard is. (That picture on his web site looks about 10
years old though!)

---Joel

On Wed, 15 Aug 2007 15:56:03 -0700, "Joel Kolstad"
wrote:

"The Phantom" wrote in message
.. .
http://emcesd.com/tt020100.htm

Thanks for the link, Phantom.

Another one well worth looking at is:

http://www.avxcorp.com/docs/Catalogs/smpsas&p.pdf


John -- since you're not exactly enamored with Howard Johnson, do you have an
opinion on Doug Smith there? I met him once and he seems to be considerably
more "hands on" than Howard is. (That picture on his web site looks about 10
years old though!)

---Joel

On Wed, 15 Aug 2007 15:56:03 -0700, "Joel Kolstad"
wrote:

"The Phantom" wrote in message
.. .
http://emcesd.com/tt020100.htm

Thanks for the link, Phantom.

John -- since you're not exactly enamored with Howard Johnson, do you have an
opinion on Doug Smith there? I met him once and he seems to be considerably
more "hands on" than Howard is. (That picture on his web site looks about 10
years old though!)

---Joel


He seems OK, but not earth-shaking or anything; as you say, very
practical. And thank Goodness he doesn't wear those drecky
turtlenecks.

John

Hello John,


Quick ESR answer needed...

Typical 0.22uF ceramic in low voltage application (5V max), what ESR
might I expect?

Client says 0.2 Ohms

I doubt that number, but don't have anything to base my doubt on.

What say yee all?




While I was waiting for The Board to show up, I cobbled up this:

http://s2.supload.com/free/Setup.JPG/view/

http://s2.supload.com/free/Ramp.JPG/view/


That server tries some nasty pop-ups. Ricocheted off here, but others
might not be so lucky.


It's a 0.1 uF, 0805 cap soldered across a 50 ohm transmission line.
It's being driven from (we pause for this commercial message...)

http://www.highlandtechnology.com/DSS/P400DS.html

which is setup for 5 volts out, 50 ohms, so it's dumping a 100 mA step
into the cap with about a 1 ns risetime. The scope bandwidth is 20
GHz.


What's the ballpark s.e.d. discount price for that one? I am using the
old Philips PM5785B for stuff like this and it's fine for me. But I have
a client who may need to generate test pulses with less jitter than the
Philips can do. How much oomph can you get out of that optional 50V
output? We'd need more than 5V, sometimes a lot more.


The first glitch is L di/dt, roughly estimated as 1.5 nH.
Extrapolating the slope back to the start gives very roughly 20
milliohms, but it's hard to resolve that small a resistance with this
rig. The glitch at about 10 ns is a cable reflection.

This cap is pretty much a dead short in the, say, 3 ns time frame.


--
Regards, Joerg

http://www.analogconsultants.com

On Thu, 16 Aug 2007 18:49:36 GMT, Joerg
wrote:

Hello John,


Quick ESR answer needed...

Typical 0.22uF ceramic in low voltage application (5V max), what ESR
might I expect?

Client says 0.2 Ohms

I doubt that number, but don't have anything to base my doubt on.

What say yee all?




While I was waiting for The Board to show up, I cobbled up this:

http://s2.supload.com/free/Setup.JPG/view/

http://s2.supload.com/free/Ramp.JPG/view/


That server tries some nasty pop-ups. Ricocheted off here, but others
might not be so lucky.


[snip]

No such problems here (Firefox v2.0.0.6).

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

America: Land of the Free, Because of the Brave

Jim Thompson wrote:

On Thu, 16 Aug 2007 18:49:36 GMT, Joerg
wrote:


Hello John,


Quick ESR answer needed...

Typical 0.22uF ceramic in low voltage application (5V max), what ESR
might I expect?

Client says 0.2 Ohms

I doubt that number, but don't have anything to base my doubt on.

What say yee all?




While I was waiting for The Board to show up, I cobbled up this:

http://s2.supload.com/free/Setup.JPG/view/

http://s2.supload.com/free/Ramp.JPG/view/


That server tries some nasty pop-ups. Ricocheted off here, but others
might not be so lucky.


[snip]

No such problems here (Firefox v2.0.0.6).


I didn't have any here but you can see the attempts. Only web sites on
the more rough-and-tumble side do that.

--
Regards, Joerg

http://www.analogconsultants.com

On Thu, 16 Aug 2007 18:49:36 GMT, Joerg
wrote:

Hello John,


Quick ESR answer needed...

Typical 0.22uF ceramic in low voltage application (5V max), what ESR
might I expect?

Client says 0.2 Ohms

I doubt that number, but don't have anything to base my doubt on.

What say yee all?




While I was waiting for The Board to show up, I cobbled up this:

http://s2.supload.com/free/Setup.JPG/view/

http://s2.supload.com/free/Ramp.JPG/view/


That server tries some nasty pop-ups. Ricocheted off here, but others
might not be so lucky.

Oh. I've never seen their popups, just a few static ads. I'm using
Firefox.




It's a 0.1 uF, 0805 cap soldered across a 50 ohm transmission line.
It's being driven from (we pause for this commercial message...)

http://www.highlandtechnology.com/DSS/P400DS.html

which is setup for 5 volts out, 50 ohms, so it's dumping a 100 mA step
into the cap with about a 1 ns risetime. The scope bandwidth is 20
GHz.


What's the ballpark s.e.d. discount price for that one? I am using the
old Philips PM5785B for stuff like this and it's fine for me. But I have
a client who may need to generate test pulses with less jitter than the
Philips can do. How much oomph can you get out of that optional 50V
output? We'd need more than 5V, sometimes a lot more.

List price is $3840, with options for OCXO, Ethernet, and stuff like
that. Jitter for short delays is around 6 ps RMS, increasing to 10's
of ps for long delays. The HV option is $600, and puts 50 volts into
50 ohms with risetime about 1.8 ns. I did this with 2N7002's! I can
email a manual to anybody who's interested.

John

John Larkin wrote:

On Thu, 16 Aug 2007 18:49:36 GMT, Joerg
wrote:


Hello John,


Quick ESR answer needed...

Typical 0.22uF ceramic in low voltage application (5V max), what ESR
might I expect?

Client says 0.2 Ohms

I doubt that number, but don't have anything to base my doubt on.

What say yee all?




While I was waiting for The Board to show up, I cobbled up this:

http://s2.supload.com/free/Setup.JPG/view/

http://s2.supload.com/free/Ramp.JPG/view/


That server tries some nasty pop-ups. Ricocheted off here, but others
might not be so lucky.


Oh. I've never seen their popups, just a few static ads. I'm using
Firefox.



It's a 0.1 uF, 0805 cap soldered across a 50 ohm transmission line.
It's being driven from (we pause for this commercial message...)

http://www.highlandtechnology.com/DSS/P400DS.html

which is setup for 5 volts out, 50 ohms, so it's dumping a 100 mA step
into the cap with about a 1 ns risetime. The scope bandwidth is 20
GHz.


What's the ballpark s.e.d. discount price for that one? I am using the
old Philips PM5785B for stuff like this and it's fine for me. But I have
a client who may need to generate test pulses with less jitter than the
Philips can do. How much oomph can you get out of that optional 50V
output? We'd need more than 5V, sometimes a lot more.


List price is $3840, with options for OCXO, Ethernet, and stuff like
that. Jitter for short delays is around 6 ps RMS, increasing to 10's
of ps for long delays. The HV option is $600, and puts 50 volts into
50 ohms with risetime about 1.8 ns. I did this with 2N7002's! I can
email a manual to anybody who's interested.


I like that classy fluorescent display. Yes, I'd be interested in a manual:

jsc
at ieee dot org

(that one is less typing than my biz email address)

--
Regards, Joerg

http://www.analogconsultants.com

John Larkin wrote:
On Thu, 16 Aug 2007 18:49:36 GMT, Joerg
wrote:


List price is $3840, with options for OCXO, Ethernet, and stuff like
that. Jitter for short delays is around 6 ps RMS, increasing to 10's
of ps for long delays. The HV option is $600, and puts 50 volts into
50 ohms with risetime about 1.8 ns. I did this with 2N7002's! I can
email a manual to anybody who's interested.

John,
I'm interested in a manual too.
to tschaggelar (at) dplanet (dot) ch

Rene
--
Ing.Buero R.Tschaggelar - http://www.ibrtses.com
& commercial newsgroups - http://www.talkto.net
Spilchbüel 1, 8342 Wernetshausen, Switzerland
ph. ++41 55 266 19 66 & ++41 44 937 23 67