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#1
September 21st 05, 10:14 PM
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Buffer Amp IC suggestions plse
Hi,
Ive been trying to locate a suitable unity gain buffer amplifier IC that can drive a 50 load. Application is to buffer a VCO output at 5Mhz. Needs to be 8pin DIP and operate on a single-ended supply. I had found what I wanted in the CLC109, but cant seem to find a supplier. Any suggestions greatly appreciated regarding type and supplier that is user friendly to international countries. JEFF ZL3JK New Zealand |
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#2
September 21st 05, 11:25 PM
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Jeff wrote...
Ive been trying to locate a suitable unity gain buffer amplifier IC that can drive a 50 load. Application is to buffer a VCO output at 5Mhz. Needs to be 8pin DIP LTC's LT1206 comes in TO220, miniDIP and soic packages, and Digi-Key has them in stock for $6.25 each... http://rocky.digikey.com/WebLib/Line...ata/LT1206.pdf http://www.digikey.com/scripts/DkSea...ail?Ref=329191 and operate on a single-ended supply. Oops, +/-5V supply. What's your signal voltage? And did you want your output to have a 50-ohm source impedance? -- Thanks, - Win |
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#3
September 21st 05, 11:56 PM
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Needs to drive into 50 ohms. input level approx 150mV at 5Mhz
"Winfield Hill" wrote in message ... Jeff wrote... Ive been trying to locate a suitable unity gain buffer amplifier IC that can drive a 50 load. Application is to buffer a VCO output at 5Mhz. Needs to be 8pin DIP LTC's LT1206 comes in TO220, miniDIP and soic packages, and Digi-Key has them in stock for $6.25 each... http://rocky.digikey.com/WebLib/Line...ata/LT1206.pdf http://www.digikey.com/scripts/DkSea...ail?Ref=329191 and operate on a single-ended supply. Oops, +/-5V supply. What's your signal voltage? And did you want your output to have a 50-ohm source impedance? -- Thanks, - Win |
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#4
September 22nd 05, 01:37 AM
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Jeff wrote...
Needs to drive into 50 ohms. input level approx 150mV at 5Mhz Winfield Hill wrote ... Jeff wrote... Ive been trying to locate a suitable unity gain buffer amplifier IC that can drive a 50 load. Application is to buffer a VCO output at 5Mhz. Needs to be 8pin DIP LTC's LT1206 comes in TO220, miniDIP and soic packages, and Digi-Key has them in stock for $6.25 each... http://rocky.digikey.com/WebLib/Line...ata/LT1206.pdf http://www.digikey.com/scripts/DkSea...ail?Ref=329191 and operate on a single-ended supply. Oops, +/-5V supply. What's your signal voltage? And did you want your output to have a 50-ohm source impedance? Unless you source with 50 ohms (2x signal plus 50-ohm resistor), and terminate with 50-ohms, the issue becomes how much cable capacitance? Either the load looks resistive (100 ohms in the former case) or capacitive. -- Thanks, - Win |
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#5
September 30th 05, 11:36 PM
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Winfield Hill wrote:
Jeff wrote... Needs to drive into 50 ohms. input level approx 150mV at 5Mhz Winfield Hill wrote ... Jeff wrote... Ive been trying to locate a suitable unity gain buffer amplifier IC that can drive a 50 load. Application is to buffer a VCO output at 5Mhz. Needs to be 8pin DIP LTC's LT1206 comes in TO220, miniDIP and soic packages, and Digi-Key has them in stock for $6.25 each... http://rocky.digikey.com/WebLib/Line...ata/LT1206.pdf http://www.digikey.com/scripts/DkSea...ail?Ref=329191 and operate on a single-ended supply. Oops, +/-5V supply. What's your signal voltage? And did you want your output to have a 50-ohm source impedance? Unless you source with 50 ohms (2x signal plus 50-ohm resistor), and terminate with 50-ohms, the issue becomes how much cable capacitance? Either the load looks resistive (100 ohms in the former case) or capacitive. I would say it depends on the cable you choose. If there is a 50 Ohm load and you connect it to your buffer amplifier with 50 Ohm coaxial cable, then the buffer amplifier will see a 50 Ohm resistive load, not capacitive at all. It is probably still wise to use the gain-of-two amplifier and 50 Ohm source resistor in case the load happens to be a poor match. If you really don't need this feature then I would be tempted to use an emitter follower with just one transistor. (Do they make transistors in DIP-8 packages?) Chris |
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#6
September 22nd 05, 06:27 AM
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On Wed, 21 Sep 2005 15:25:09 -0700, Winfield Hill wrote:
Jeff wrote... Ive been trying to locate a suitable unity gain buffer amplifier IC that can drive a 50 load. Application is to buffer a VCO output at 5Mhz. Needs to be 8pin DIP LTC's LT1206 comes in TO220, miniDIP and soic packages, and Digi-Key has them in stock for $6.25 each... http://rocky.digikey.com/WebLib/Line...ata/LT1206.pdf http://www.digikey.com/scripts/DkSea...ail?Ref=329191 and operate on a single-ended supply. Oops, +/-5V supply. What's your signal voltage? And did you want your output to have a 50-ohm source impedance? Maybe an LT1191? digikey #: LT1191CN8-ND (24 in stock at USD 3.25) http://rocky.digikey.com/WebLib/Line...ata/LT1191.pdf --Mac |
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#7
September 22nd 05, 12:49 PM
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Mac wrote...
Maybe an LT1191? digikey #: LT1191CN8-ND (24 in stock at USD 3.25) http://rocky.digikey.com/WebLib/Line...ata/LT1191.pdf Ouch, a 30mA supply current! -- Thanks, - Win |
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#8
September 22nd 05, 03:50 PM
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Winfield Hill wrote: Mac wrote... Maybe an LT1191? digikey #: LT1191CN8-ND (24 in stock at USD 3.25) http://rocky.digikey.com/WebLib/Line...ata/LT1191.pdf Ouch, a 30mA supply current! Well- why not your super-duper 74HCU04 linear amp or whatever it was?- is that available in Tiny Logic? |
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#9
September 22nd 05, 12:14 AM
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Jeff wrote:
Hi, Ive been trying to locate a suitable unity gain buffer amplifier IC that can drive a 50 load. Application is to buffer a VCO output at 5Mhz. Needs to be 8pin DIP and operate on a single-ended supply. I had found what I wanted in the CLC109, but cant seem to find a supplier. Any suggestions greatly appreciated regarding type and supplier that is user friendly to international countries. JEFF ZL3JK New Zealand An AD817 can deliver +-50 mA and has a gain bandwidth product of 50 MHz. http://www.analog.com/UploadedFiles/...66266ad817.pdf 4$ from Digikey. Good for either a gain 1 buffer or a gain 2 with series 50 ohm resistor, 50 ohm source. |
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#10
September 22nd 05, 03:03 AM
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Thanks. The AD817 looks good, and I can source it locally from Australia.
Thanks all for your help. JEFF "John Popelish" wrote in message ... Jeff wrote: Hi, Ive been trying to locate a suitable unity gain buffer amplifier IC that can drive a 50 load. Application is to buffer a VCO output at 5Mhz. Needs to be 8pin DIP and operate on a single-ended supply. I had found what I wanted in the CLC109, but cant seem to find a supplier. Any suggestions greatly appreciated regarding type and supplier that is user friendly to international countries. JEFF ZL3JK New Zealand An AD817 can deliver +-50 mA and has a gain bandwidth product of 50 MHz. http://www.analog.com/UploadedFiles/...66266ad817.pdf 4$ from Digikey. Good for either a gain 1 buffer or a gain 2 with series 50 ohm resistor, 50 ohm source. |
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