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#### fm101

##### Member level 5
hello,
On the MC1496 modulator/demodulator. datasheet(link:https://www.onsemi.com/pdf/datasheet/mc1496-d.pdf), in typical application section, there is one circuit(Fig 25) where single supply is used. How to use single supply for the other application circuits(fig 26,27,28)? will the other circuit also work with single supply? also the single supply uses +12V, can we use other voltage like +5V?

thank you all

Solution
Read the datasheet thoroughly. It has a biasing chapter that explains the minimal supply conditions and how all inputs must be biased. It doesn't exactly calculate minimal supply voltage but it's surely above 8V. Consider also that you have about no signal swing at minimal supply voltage.
Read the datasheet thoroughly. It has a biasing chapter that explains the minimal supply conditions and how all inputs must be biased. It doesn't exactly calculate minimal supply voltage but it's surely above 8V. Consider also that you have about no signal swing at minimal supply voltage.

There is no characterization data for 5V and I would posit that there
is not enough headroom to support any significant dynamic range at
those levels.

Yes to other circuits single supply, you just have to bias them properly.

Regards, Dana.

Read the datasheet thoroughly. It has a biasing chapter that explains the minimal supply conditions and how all inputs must be biased. It doesn't exactly calculate minimal supply voltage but it's surely above 8V. Consider also that you have about no signal swing at minimal supply voltage.
above 8V? can you indicate how? could not find info on this
thank you
--- Updated ---

There is no characterization data for 5V and I would posit that there
is not enough headroom to support any significant dynamic range at
those levels.

Yes to other circuits single supply, you just have to bias them properly.

Regards, Dana.
thank you this doc describes more in details

thank you this doc describes more in details
The same bias chapter is in the datasheet as well. You get 8V by adding up the voltage values.

The same bias chapter is in the datasheet as well. You get 8V by adding up the voltage values.
hmm...could you tell which voltages values?

thank you

MC1496 is one of the oldest chips, which after 50 years (1972) since its first production by Motorola, is still in production. Regarding supplied power from a double source, things are a bit simpler, because the chip was initially designed for a single power source.
In all schemes where there is a dual power source, the negative (-) source can be connected to ground, and very small bias adjustments will be needed.
I tested the MC1496 in the SMD version at +3.3V and it works decent as a balanced modulator.
See that major Spice simulators have MC1496 model, and you can play with it.

MC1496 is one of the oldest chips, which after 50 years (1972) since its first production by Motorola, is still in production. Regarding supplied power from a double source, things are a bit simpler, because the chip was initially designed for a single power source.
In all schemes where there is a dual power source, the negative (-) source can be connected to ground, and very small bias adjustments will be needed.
I tested the MC1496 in the SMD version at +3.3V and it works decent as a balanced modulator.
See that major Spice simulators have MC1496 model, and you can play with it.
hi, since you have working experience can you tell whether it would also work at high frequencies in MHz ranges? possibly in 100MHz with appropriate filtering of the harmonics?

100MHz is very optimistic. I would put the overall performance limits to about 50MHz.
First performance that will brake with increased frequency will be the carrier suppression.
To be mentioned, the main difference with or without negative supply voltage is also the carrier suppression. About 10dB better suppression when using negative supply voltage.

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