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Science Forum Index » Electronics - Components Forum » CD4060, datasheet weirdness
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| Eeyore |
 Posted: Sat Jan 20, 2007 9:12 pm |
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John Fields wrote:
Quote: Eeyore <rabbitsfriendsandrelations@hotmail.com> wrote:
Terry Given wrote:
AIUI the US military wants new air frames designed for 100year lives.
Probably counter-productive for fighters.
The Russians went exactly the other way with modern Migs and Sukhois.
---
And they won, huh?
Those fighters are damn good.
Graham |
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| Tony Williams |
| Posted: Sat Jan 20, 2007 10:42 pm |
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In article <v8ash.2570$O02.2066@newssvr11.news.prodigy.net>,
Joerg <notthisjoergsch@removethispacbell.net> wrote:
Quote: For 5V it states the frequency as 23kHz +/-10%. But the usual
formula is f=1/(2.2*Rx*Cx) and that comes to about 45kHz. I
can't imagine these things to have more than a few ten pF in
internal capacitances so this doesn't compute. Look at the 4th
page (page 3-161):
The Motorola MC14060B data sheet does give consistent
frequencies, between a calculation based on the sum
given on Fig3 and and readings off the graph in Fig5,
(for C=200pf and R=56K). So the CD4060 data sheet is
misleading, (or wrong), cause unknown.
--
Tony Williams. |
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| John Fields |
| Posted: Sat Jan 20, 2007 10:58 pm |
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On Sat, 20 Jan 2007 23:30:13 +0000, Eeyore
<rabbitsfriendsandrelations@hotmail.com> wrote:
Quote:
Terry Given wrote:
AIUI the US military wants new air frames designed for 100year lives.
Probably counter-productive for fighters.
The Russians went exactly the other way with modern Migs and Sukhois.
---
And they won, huh?
--
JF |
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| John Fields |
| Posted: Sun Jan 21, 2007 12:04 pm |
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On Sun, 21 Jan 2007 01:12:01 +0000, Eeyore
<rabbitsfriendsandrelations@hotmail.com> wrote:
Quote:
John Fields wrote:
Eeyore <rabbitsfriendsandrelations@hotmail.com> wrote:
Terry Given wrote:
AIUI the US military wants new air frames designed for 100year lives.
Probably counter-productive for fighters.
The Russians went exactly the other way with modern Migs and Sukhois.
---
And they won, huh?
Those fighters are damn good.
---
Well, no shit Sherlock?
--
JF |
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| Marte Schwarz |
| Posted: Sun Jan 21, 2007 7:31 pm |
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Hi Jörg,
Quote: CD4060, hoping to find some in TSSOP stock.
For 5V it states the frequency as 23kHz +/-10%. But the usual formula is
f=1/(2.2*Rx*Cx) and that comes to about 45kHz. I can't imagine these
Sorry all its latenight here so I'll do it quickly in german, Jörg will
understand it ;-)
Die Umschaltschwellen liegen bei 2/3 der Versorgungsspannung bzw 1/3. Eine
Ladephase dauert also 67/63 der Zeitkonstante (63% ist 1/e) also 1,1 RC. Mit
Entladephase also 2,2 RC. Warum das TI-Datenblatt andere Zahlen nennt, wird
deren Geheimnis bleiben :-(
Marte |
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| Joerg |
| Posted: Sun Jan 21, 2007 7:48 pm |
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Marte Schwarz wrote:
Quote: Hi Jörg,
CD4060, hoping to find some in TSSOP stock.
For 5V it states the frequency as 23kHz +/-10%. But the usual formula is
f=1/(2.2*Rx*Cx) and that comes to about 45kHz. I can't imagine these
Sorry all its latenight here so I'll do it quickly in german, Jörg will
understand it ;-)
Die Umschaltschwellen liegen bei 2/3 der Versorgungsspannung bzw 1/3. Eine
Ladephase dauert also 67/63 der Zeitkonstante (63% ist 1/e) also 1,1 RC. Mit
Entladephase also 2,2 RC. Warum das TI-Datenblatt andere Zahlen nennt, wird
deren Geheimnis bleiben :-(
Translation of the last sentence: "As to why the TI datasheet offers
other numbers will remain a mystery"
Well, that's exactly why I posted. Maybe I'll ask TI but it's just a
scanned Harris sheet. Last time I found something like this with another
mfg the response was something like "Oh drat, thanks, we'll look into it".
--
Regards, Joerg
http://www.analogconsultants.com |
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| Mark Aitchison |
| Posted: Sat Feb 10, 2007 7:18 pm |
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Ancient_Hacker wrote:
Quote: Joerg wrote:
For 5V it states the frequency as 23kHz +/-10%. But the usual formula is
f=1/(2.2*Rx*Cx) and that comes to about 45kHz.
Either there is dividing by two, or it uses the RC ramp on both the
charge and discharge parts of the cycle..
Yep.
The factor of two is the key. It isn't that the output is coming from a
divider, it is that the "T=2.2 RxCx" formula with Fig 12 on page 3-160
isn't backed by much text to make it clear... T has to be the time
constant of the RC circuit (allowing for when through the cycle the gate
switches), so it is the time for each *half* of the cycle, not the
period of the oscillation. So the formula for the frequency should be:
0.5/(2.2 RxCx),
plus a bit of adjustment for supply voltage etc. The datasheet really
should have made this clearer. |
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| Fred Bloggs |
| Posted: Sat Feb 10, 2007 7:41 pm |
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Mark Aitchison wrote:
Quote: Ancient_Hacker wrote:
Joerg wrote:
For 5V it states the frequency as 23kHz +/-10%. But the usual formula is
f=1/(2.2*Rx*Cx) and that comes to about 45kHz.
Either there is dividing by two, or it uses the RC ramp on both the
charge and discharge parts of the cycle..
Yep.
The factor of two is the key. It isn't that the output is coming from a
divider, it is that the "T=2.2 RxCx" formula with Fig 12 on page 3-160
isn't backed by much text to make it clear... T has to be the time
constant of the RC circuit (allowing for when through the cycle the gate
switches), so it is the time for each *half* of the cycle, not the
period of the oscillation. So the formula for the frequency should be:
0.5/(2.2 RxCx),
plus a bit of adjustment for supply voltage etc. The datasheet really
should have made this clearer.
The numbers work out in the HEF4060B datasheet and figure 8. |
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