Ultra low frequency VCO
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From: Jim Thompson on 12 Jul 2010 13:34 On Mon, 12 Jul 2010 10:13:03 -0700, "Joel Koltner" <zapwireDASHgroups(a)yahoo.com> wrote: >"Jim Thompson" <To-Email-Use-The-Envelope-Icon(a)On-My-Web-Site.com> wrote in >message news:dcim36poktoi3gc0keapvnbjlpsri0lqj4(a)4ax.com... > >[coaxial ceramic resonators] > >> I've been "using" them... designing them into GPS LO's since before >> you were born ;-) > >What's the advantage -- for you -- over crystals? Just lower cost? > >---Joel Small, hi-Q, but reasonably pull-able, to phase lock. (Cost never matters to me, I'm never paying ;-) ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | Obama isn't going to raise your taxes...it's Bush' fault: Not re- newing the Bush tax cuts will increase the bottom tier rate by 50%
From: Joel Koltner on 12 Jul 2010 13:52 "Jim Thompson" <To-Email-Use-The-Envelope-Icon(a)On-My-Web-Site.com> wrote in message news:1ekm36hmf1f3egiu3uvg9olh3ieb0e4cq0(a)4ax.com... >>What's the advantage -- for you -- over crystals? Just lower cost? > Small, hi-Q, but reasonably pull-able, to phase lock. Ah, gotcha -- I wans't thinking (the really rather obvious bit) that there's no such thing as a 1575.42MHz crystal. :-) Speaking of PLLs... do you happen to know why so many of them have rather high (hundreds of MHz) lower frequency limits? E.g., this seemingly-popular part: http://www.national.com/pf/LM/LMX2485.html ... only goes down to 500MHz on one of the PLLs; National has a slightly different version -- http://www.national.com/pf/LM/LMX2485E.html -- that goes down to 50MHz. What's different inside, would you think? Discussions at work here and with Joerg have postulated: -- AC coupling of the input amplifiers? -- The fastest counters (dividers) are actually dynamic circuitry, and hence they really can't count too slowly or they forget where they were. (1, 2, 3... umm? 3? 1? Where was I again? La-la-la-la-la I'm so confused!) There aren't a lot of low-power PLL-based synthesizers in the "more than a handful of MHz"-CD4046 (and derivative) territory and these multi-hundred-MHz+ monsters. We're after some 45MHz PLLs, and so far the ADF4001 is one of the very few attractive-looking candidates. Thanks for the help, ---Joel
From: Jim Thompson on 12 Jul 2010 14:12 On Mon, 12 Jul 2010 10:52:10 -0700, "Joel Koltner" <zapwireDASHgroups(a)yahoo.com> wrote: >"Jim Thompson" <To-Email-Use-The-Envelope-Icon(a)On-My-Web-Site.com> wrote in >message news:1ekm36hmf1f3egiu3uvg9olh3ieb0e4cq0(a)4ax.com... >>>What's the advantage -- for you -- over crystals? Just lower cost? >> Small, hi-Q, but reasonably pull-able, to phase lock. > >Ah, gotcha -- I wans't thinking (the really rather obvious bit) that there's >no such thing as a 1575.42MHz crystal. :-) Rather than think "resonator", think very-low-loss shorted-termination transmission line stub. (Think college days :-) > >Speaking of PLLs... do you happen to know why so many of them have rather high >(hundreds of MHz) lower frequency limits? E.g., this seemingly-popular part: >http://www.national.com/pf/LM/LMX2485.html ... only goes down to 500MHz on one >of the PLLs; National has a slightly different version -- >http://www.national.com/pf/LM/LMX2485E.html -- that goes down to 50MHz. >What's different inside, would you think? Don't know. Might be AC-coupling internally... makes dividers less prone to offset voltages at those frequencies. > >Discussions at work here and with Joerg have postulated: > >-- AC coupling of the input amplifiers? Yep. See above. >-- The fastest counters (dividers) are actually dynamic circuitry, and hence >they really can't count too slowly or they forget where they were. (1, 2, >3... umm? 3? 1? Where was I again? La-la-la-la-la I'm so confused!) Indeed ;-) > >There aren't a lot of low-power PLL-based synthesizers in the "more than a >handful of MHz"-CD4046 (and derivative) territory and these multi-hundred-MHz+ >monsters. We're after some 45MHz PLLs, and so far the ADF4001 is one of the >very few attractive-looking candidates. > >Thanks for the help, >---Joel > > I rarely keep track of OTC offerings, since I'm really in the designing whole SOC business. Occasionally a client will say, "I want all this garbage on a single chip", and hand me a pile of data sheets. Then I have to analyze how it all works. That actually works out well with usually significant space and power compaction, since I/O can use up a lot of chip area and power. ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | Obama isn't going to raise your taxes...it's Bush' fault: Not re- newing the Bush tax cuts will increase the bottom tier rate by 50%
From: Joel Koltner on 12 Jul 2010 14:30 Hi Jim, "Jim Thompson" <To-Email-Use-The-Envelope-Icon(a)On-My-Web-Site.com> wrote in message news:s5mm365lej39010hb39ghkrsobfq4u9819(a)4ax.com... > I rarely keep track of OTC offerings, since I'm really in the > designing whole SOC business. Yeah, that's becoming a bit unfortunate for those of us doing board-level designs where the quantities just aren't there for doing custom ICs -- many of the RF parts that are left aren't particularly optimized for power consumption, since they're either parts that have been around forever (big transistors, I suppose) or they're aimed at the aerospace/military market where they figure you've got a nuclear reactor to power the thing. We're got a wireless handheld (battery-powered) widget that, between the numerous synthesized LOs, mixers, and amps might double as a pretty good hand-warmer. :-) ---Joel
From: Jim Thompson on 12 Jul 2010 14:42
On Mon, 12 Jul 2010 11:30:16 -0700, "Joel Koltner" <zapwireDASHgroups(a)yahoo.com> wrote: >Hi Jim, > >"Jim Thompson" <To-Email-Use-The-Envelope-Icon(a)On-My-Web-Site.com> wrote in >message news:s5mm365lej39010hb39ghkrsobfq4u9819(a)4ax.com... >> I rarely keep track of OTC offerings, since I'm really in the >> designing whole SOC business. > >Yeah, that's becoming a bit unfortunate for those of us doing board-level >designs where the quantities just aren't there for doing custom ICs -- many of >the RF parts that are left aren't particularly optimized for power >consumption, since they're either parts that have been around forever (big >transistors, I suppose) or they're aimed at the aerospace/military market >where they figure you've got a nuclear reactor to power the thing. > >We're got a wireless handheld (battery-powered) widget that, between the >numerous synthesized LOs, mixers, and amps might double as a pretty good >hand-warmer. :-) > >---Joel Post your questions and I'll try to answer. Larkin will certainly jump in and shovel a pile of BS in your direction :-) I'm thinking the way to resolve this Larkin statement, "... charge is not conserved" in... Message-ID: <3b893612tjjndo8o4v1evro050nonjgp41(a)4ax.com> is for me to post the solution on my website. BUT in a password-protected ZIP file. White-listed individuals can contact me for the password and see how it works, that way Larkin will be prevented from seeing it and claiming "that's what I really meant... let him choke on his own drool :-) I'll let you know when it's up there. Funny. Yesterday, while cooling my heels at a going-away swim party for a granddaughter (they're moving to Rancho Mirage... Renee's father is in ill-health, so she's going to run his automotive parts business), I sat there in the shade, in 112�F heat and "played" the circuit in my head... that's how I figured out where the missing charge comes from ;-) ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | Obama isn't going to raise your taxes...it's Bush' fault: Not re- newing the Bush tax cuts will increase the bottom tier rate by 50% |