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Low noise inverter chip for biasing GaAs Fet's gate

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nandopg

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inverter chip

I am looking for a low noise inverter chip (8pins) to generate the negative voltage for biasing GaAs Fet's gate.
I tried the Maxim and Linear Technology chips. They performed good but they did'nt accomplish with the temperature range requiride.
Does somebody suggest me some other manufacturer?

Thanks in advance

NandoPG
 

Bagster

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noise negative voltage

i know quite a few.

for single stage, you can either do this using a custom IC or using discrete components. i am assuming you want to bias at a fixed voltage and with a constant current. what is the gate current, how much do you need. What FET are you using.
If it is low then you can use a crude method. A lm555cm timer configured as a free running oscillator, two diodes an a capacitor or two added to this can generate a unregulated negative voltage. Use a simple BJT set up a circuit that will bias the DUT at a known voltage and current. (if you need a schematic let me know).
Solution 2.
Zetex make asics that do all this for you. There are loads of flavours for every situation.

solution3

NJRC do a device based on the icm7660 switched capacitor invertor. This has two integrated opamps to help set up the bias conditions.

If you need anymore info ask


Regards

Bagster :roll:
 

shanren

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inverter fet bias

hi,what temp range you request?and how much current do you need?i have used a -40 to 85 degree ,it is a pump converter 7660.many company have such chips,such as maxim,linear tech,national.if the noise is too high,use a rc or lc filter.or use a LDO to get better performance.you can visit:
h**p://www.maxim-ic.com
h**p://www.linear.com
h**p://www.national.com
h**p://www.ti.com
they have many pumps ,even sot23.they also have many LDOs.
hope this can help you.
 

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