AD834 is such an excellent multiplier, why do we rarely see people using it?

[daisizhou]

Hello everyone

I plan to build a high frequency power measurement device,The general operating frequency is 800K-3Mhz,To measure RMS voltage and power, I looked at a lot of references.
I found the AD834 to be a very good multiplier,I plan to use non-inductive resistors to decay and eventually use the AD834 to measure.
But few people use it to make power measurement devices,I do not know why

https://www.analog.com/en/products/ad834.html

[mikeselectricstuff]

Cost mostly - you an get some really nice ADC/DAC/DSP for way less than the cost of that part.

[daisizhou]

But can the bandwidth also reach a maximum of 500MHZ?There is also 0.5% accuracy

[moffy]

But can the bandwidth also reach a maximum of 500MHZ?There is also 0.5% accuracy

That's why it is expensive, making it uncommon, for me about $80 AUD at Mouser.

[andrewtaylor]

But few people use it to make power measurement devices,I do not know why

The high price and it is single source only  from AD -- so that's main reasons.

Same with e the LT-chips for RMS measurement (10hz..50/100Mhz possible) -
obsolete since decade.

(btw. if you didn't aware: LT was sold to AD).

[dzseki]

If frequency requirements are not very high , you can also consider AD835 (250MHz), which is a touch cheaper, and has already voltage outputs, plus with the added "+Z" input it can do a few more tricks too.

[daisizhou]

But few people use it to make power measurement devices,I do not know why

The high price and it is single source only  from AD -- so that's main reasons.

Same with e the LT-chips for RMS measurement (10hz..50/100Mhz possible) -
obsolete since decade.

(btw. if you didn't aware: LT was sold to AD).

I remember the LT1088, but unfortunately it has been discontinued.
For RMS measurement, I only know that AD834 is the best choice.

[daisizhou]

If frequency requirements are not very high , you can also consider AD835 (250MHz), which is a touch cheaper, and has already voltage outputs, plus with the added "+Z" input it can do a few more tricks too.

Are AD834 and AD835 interchangeable?
I rarely see any enthusiasts using them to make RMS measurement circuits or other DIY works on the Internet.

[RoGeorge]

I've bought once a batch of AD835 from Aliexpress, in 2015.  It was $1.48/pcs in batches of 10pcs. and free shipping.

At first I was afraid it would be fake chips, though I've DIY a breakout board for one of those AD835, and measure it at low frequency on a breadboard.  The chip was indeed a working analog multiplier.  To this day, still didn't test them at high frequency.  AD835 should work up to 250MHz.


Source:  https://hackaday.io/project/7574-the-devil-is-in-the-details/log/26074-diy-breadboard-friendly-soic-breakout-boards

From traceable vendors the cost was many times higher, but I don't recall the official price. 

[daisizhou]

I've bought once a batch of AD835 from Aliexpress, in 2015.  It was $1.48/pcs in batches of 10pcs. and free shipping.

At first I was afraid it would be fake chips, though I've DIY a breakout board for one of those AD835, and measure it at low frequency, on a breadboard.  The chip was indeed a working analog multiplier.  To this day, still didn't test them at high frequency, AD835 should work up to 250MHz.


Source:  https://hackaday.io/project/7574-the-devil-is-in-the-details/log/26074-diy-breadboard-friendly-soic-breakout-boards

From traceable vendors the cost was many times higher, but I don't recall exactly the official price.

Yes.AD834 sop8 package is very cheap, DIP8 may be slightly more expensive。
The reason why I chose AD834 is also based on its price. It seems to be very cheap. The purchase quantity can be 1 or 2, which is up to the buyer.

[RoGeorge]

That's about $0.48/pcs for a 500MHz AD834, right? 

The Analog Devices webpages for AD835 and AD834 list them as starting from $16.93/pcs respectively $30.56/pcs for 1ku.

Don't know what's the catch, but there must be a reason why the Chinese AD834 is more than 60 times cheaper. 

[daisizhou]

That's about $0.48/pcs for a 500MHz AD834, right? 

The Analog Devices webpages for AD835 and AD834 list them as starting from $16.93/pcs respectively $30.56/pcs for 1ku.

Don't know what's the catch, but there must be a reason why the Chinese AD834 is more than 60 times cheaper. 

Yes  It may be old, but for amateur players, it's not important as long as the chip function is normal

[moffy]

That's about $0.48/pcs for a 500MHz AD834, right? 

The Analog Devices webpages for AD835 and AD834 list them as starting from $16.93/pcs respectively $30.56/pcs for 1ku.

Don't know what's the catch, but there must be a reason why the Chinese AD834 is more than 60 times cheaper. 

Caveat emptor or buyer beware.

[dzseki]

If frequency requirements are not very high , you can also consider AD835 (250MHz), which is a touch cheaper, and has already voltage outputs, plus with the added "+Z" input it can do a few more tricks too.

Are AD834 and AD835 interchangeable?
I rarely see any enthusiasts using them to make RMS measurement circuits or other DIY works on the Internet.

They are different. AD834 has a complementary current output ("open collector") that is somewhat awkward to work with. On the other hand AD835 has a single conventional voltage output.
Also AD834 is a pure multiplier with a transfer function: W=X*Y
While AD835 has an adder input oo, so the transfer function goes like: W=X*Y+Z
I've made various projects with AD834 and AD835 as a contrast modulator for high resolution CRT projectors for home theater enthusiasts.
I still have a few chips and boards laying around.

[Postal2]

This chip (or similar) can be used to build a sound converter to speak with the voice of a clown.