New schematic symbol

[Boncuk]

Hi all,

till now it was not clear from the schematic of an SMPS which of the (many) caps must be low ESR types.

The new symbol provides ease of use and clarity. The symbol stands for an extended temperature range of -55 to 105C and has been published by NIPPON CHEMI-CON.

**broken link removed**

Boncuk

 

[duffy]

The new symbol provides ease of use and clarity.

No, the new symbol does the exact opposite of that.

 

[davenn]

No, the new symbol does the exact opposite of that.

Hahaha. Yeah I would agree with your comments, all those arrows definitely add to the confusion.... Non-clarity!!

Personally haven't seen that particular symbol on either a pcb or in a cct diag.

Dave

 

[DerStrom8]

No, the new symbol does the exact opposite of that.

I think if you know what it means when you see it, it will make things much clearer, not to mention be very helpful in knowing what is needed. What's difficult to understand about it?

Thanks for posting, Hans. Very good to know!

 

[duffy]

This thing goes against Edward Tufte's theory of "data-to-ink ratio".

You could easily festoon any schematic symbol with extra lines, arrows and numbers to indicate how it handles temperature, wattage, voltage, current, vibration, humidity, light intensity, gamma radiation, and a host of other things. The net result would be a slog through a mire of squiggles instead of a brisk step to understanding.

 

[Boncuk]

April 1st is over - quite a good hit-rate



Any more questions or suggestions?

Cheers

Boncuk

 

[Reloadron]

That was good and well executed. How the hell did I miss it yesterday?

Ron

 

[MrAl]

Hi,

I agree that a special symbol for the low esr cap might be a good idea, but that particular symbol i really dont think is a very good choice. But then again it would have to be something that is so very different than usual because the 'usual' way of drawing an electrolytic cap varies considerably already, so it would have to be something extra special which means it would be very strange looking at first.

I'm also in favor of the simpler solution such as these written directly on a schematic:

C1
50uf

C2
100uf

C3
100uf, ESR<100mOhms

C4
2200uf, 10mOhms

C5
1000uf

Those above would appear on the schematic just like that.
There's no guessing which ones are low esr, and it even specs the highest allowable value OR the target value.

To go one step farther, when the esr has to be within a certain range:
2200uf, 50mOhm>ESR>10mOhm

to indicate it should be between 10 and 50 mOhms.

 

[Boncuk]

Honestly it won't be a bad idea to put a special symbol into service indicating low ESR caps right from the schematic. (That would shorten the part description using "values" quite a bit, taking care of minimum confusion.)

There are just two types of low ESR caps on the market, normal temperature range -40 to +70C and extended temperature range -55 to +105C.

Of course their ESR is different, but there is no general rule about ESR of different capacitances.
For example a 6.3V/22μF cap has an ESR of 200mΩ, while a 6.3V/47μF cap has one of 35mΩ.
(That applies to the extended temperature range caps).

For those who are interested in the production line of super low ESR caps of NIPPON-CHEMI-CON
here is the data sheet.

Kind regards to all

Boncuk

 

[DerStrom8]

That was good and well executed. How the hell did I miss it yesterday?

Ron

Oh cr@p, I had no idea

Good one Hans