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Date: Tue, 3 Jun 2003 16:22:43 +0200
Message-ID: <2D280BB697C7EE4C979C5C89925418EF1BF5E6@TNS-FBU-2E-003.corp.telenor.no>
Thread-Topic: LF: 4060 Divider
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From: jan-martin.noding@telenor.com
To: rsgb_lf_group@blacksheep.org
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Subject: RE: LF: 4060 Divider
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It is interesting to note that addition of a cooling fin could extend the operational voltage,
suggest you check some different manufacturers, like Texas and Motorola, since they often specify
CMOS devices for higher voltages than usual. Checked the 74HC4066 which one manufacturer spec'd 
up to above 12V

One problem with the 4020, 4024, 4040 and 4060-type dividers may be that they sometimes don't count 
properly on the higher frequency side, so you must adjust the input or use another xtal for the desired 
o/p, this is particularly true if you try to modify the division factor

73
Jan-Martin
LA8AK http://home.online.no/~la8ak

-----Original Message-----
From: James Moritz [mailto:j.r.moritz@herts.ac.uk]
Sent: 3. juni 2003 14:34
To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: 4060 Divider


At 11:17 02/06/2003 -0700, you wrote:
>I would like to use the M74HC4060 as a 'divide-by-64' signal source. Can
>anyone tell me the upper limit for xtals that this chip can handle? My xtal
>will be on 8.750000;  I fear that the upper limit may be around 4-6 MHz?
>
>Steve

Dear Steve, LF Group

According to the National Semiconductor data book, the 74HC4060 has a 
guaranteed minimum operating frequency of 30MHz at 5V supply. Over the 2 - 
6V supply range, typical values are 6MHz and 35MHz respectively.

The slower 4000 series CD4060 device operates over a wider voltage range - 
at 5V supply, guaranteed minumum frequency is 1.5MHz (4MHz typ); 10V, 4MHz 
(10MHz typ), 15V - 5MHz (12MHz typ). So it is a bit "iffy" for 8.75MHz, but 
it might be worth selecting a good one if, for example, you wanted 
everything to work from a 12V rail.

These figures really relate to the divider part of the chip. As far as the 
crystal oscillator part goes, this depends a lot on the crystal and the 
external components, since the "oscillator" is just a CMOS inverter which 
provides gain (although the 74HC4060 inverter has been optimised for xtal 
osc use by increasing the output impedance). But experience shows that an 
xtal around 9MHz will be no problem for the 74HC device, and will almost 
certainly work with the 4000 series device too. For details of the 
oscillator section design, have a look at 
www.fairchildsemi.com/an/AN/AN-340.pdf

Cheers, Jim Moritz
73 de M0BMU