Author Topic: What is the voltage reference part in the Fluke 87 V?  (Read 4009 times)

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Offline samgab

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What is the voltage reference part in the Fluke 87 V?
« on: December 22, 2011, 08:00:21 am »
Hi, I was wondering what is the voltage reference component in the Fluke 87 V?
Which is the specific precision component that gives it it's 0.05% basic DC Voltage accuracy rating?

Cheers.
 

Offline grenert

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Re: What is the voltage reference part in the Fluke 87 V?
« Reply #1 on: December 23, 2011, 12:30:13 am »
I think most of the Fluke handhelds use a bandgap reference (not sure the specific one in the 87V).
 

Offline The_Penguin

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Re: What is the voltage reference part in the Fluke 87 V?
« Reply #2 on: December 23, 2011, 01:28:21 am »
I think most of the Fluke handhelds use a bandgap reference (not sure the specific one in the 87V).

According to the service manual it's a 1.23v 60ppm band gap  LM285bxz-1.2d26Z
 

Offline samgab

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Re: What is the voltage reference part in the Fluke 87 V?
« Reply #3 on: December 23, 2011, 01:56:15 am »
I think most of the Fluke handhelds use a bandgap reference (not sure the specific one in the 87V).

According to the service manual it's a 1.23v 60ppm band gap  LM285bxz-1.2d26Z

Cool, thank you. Is that Service Manual for the original 87, or the 87V?... Online I could only find the PDF for the service manual of the original 87, which seemed to be quite different in quite a few ways.
 

Offline The_Penguin

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Re: What is the voltage reference part in the Fluke 87 V?
« Reply #4 on: December 23, 2011, 02:13:04 am »

Cool, thank you. Is that Service Manual for the original 87, or the 87V?... Online I could only find the PDF for the service manual of the original 87, which seemed to be quite different in quite a few ways.

Probably the original. Now that I look more closely (just got it an hour ago) the manual (PDF from the guy who sold me the 87-V on eBay) looks pretty old. It says rev 5 3/96
 

Offline samgab

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Re: What is the voltage reference part in the Fluke 87 V?
« Reply #5 on: December 23, 2011, 07:56:51 am »

Cool, thank you. Is that Service Manual for the original 87, or the 87V?... Online I could only find the PDF for the service manual of the original 87, which seemed to be quite different in quite a few ways.

Probably the original. Now that I look more closely (just got it an hour ago) the manual (PDF from the guy who sold me the 87-V on eBay) looks pretty old. It says rev 5 3/96

Hmm, yeah '96, that'll be the original. It'll have info in it about calibrating (adjusting) using trim pots, which the 87V doesn't have. Quite a few of the components looked quite different so I'm not sure if they are still using the same voltage ref.
 

Offline EEVblog

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Re: What is the voltage reference part in the Fluke 87 V?
« Reply #6 on: December 23, 2011, 10:29:53 am »
Hmm, yeah '96, that'll be the original. It'll have info in it about calibrating (adjusting) using trim pots, which the 87V doesn't have. Quite a few of the components looked quite different so I'm not sure if they are still using the same voltage ref.

The original 87 was introduced at least as early as 1988:
https://www.eevblog.com/forum/index.php?topic=354.0
http://assets.fluke.com/manuals/87______umeng0800.pdf

The 87-III was around 1997
http://assets.fluke.com/manuals/8xiii___umeng0500.pdf

So yeah, a 1996 vintage model would be the original.

Dave.
 

Offline Richard W.

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Re: What is the voltage reference part in the Fluke 87 V?
« Reply #7 on: December 25, 2011, 10:26:49 am »
Does somebody know which reference is in a Fluke 289?
 

Offline Marco1971

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Re: What is the voltage reference part in the Fluke 87 V?
« Reply #8 on: July 22, 2018, 12:34:09 pm »
Hi Richard, possibly a Linear Technology LT1019 in smd technology.

http://www.analog.com/en/products/analog-functions/voltage-references/series-voltage-references/lt1019.html

Marco.
 

Offline bluey

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Re: What is the voltage reference part in the Fluke 87 V?
« Reply #9 on: June 06, 2020, 04:00:42 am »
Hi, I was wondering what is the voltage reference component in the Fluke 87 V?
Which is the specific precision component that gives it it's 0.05% basic DC Voltage accuracy rating?

If anyone is still curious, the service manual for the 87-V/AN says its a LT1790ACS6-2.5. 87-V specs say DC accuracy is +/-(0.05%+1).
https://www.analog.com/media/en/technical-documentation/data-sheets/1790fc.pdf

I can't find a voltage reference part for 87-IV, but basic DC accuracy is quoted as 0.025%.
 
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