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level converter for high frequencies

Hi ng,

i'm currently building a serial controller between a 5V FPGA and a 3.3V microcontroller. Maybe someone of you can tell me, if there exists any common electronic component which can convert digital signals at ~ 1MHz with high level varying from 3.0 to 5.0 Volt and should output a signal with high level at 3.3Volt . (low level is always 0V)

first i tried to build a simple voltage divider with two resistors, which was only acceptable with stable 0V Low /5V High input... the other problem is a fixed input capacitor at the 3.3V device of 50pF which - in combination with my voltage divider - passed only low frequencies.

thanks in advance, Stefan

Reply to
Stefan Oedenkoven
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Hi Stefan!

Please look for "voltage translator". There are some ICs available for this purpose. You can also build them with two transtors in common base configuration. If you google for transistor voltage translator you should find it, if I am wrong just send me a mail.

Best regards,

Christoph

Reply to
Christoph Brinkhaus

with

high

Reply to
Symon

Two options: a) A lot (most new familes?) of CMOS Logic devices ( TI, Philips, Fairchild et al ) have overdrive tolerance, so poered from 3.3V, they do not mind 5V overdrive on IPs. Use a set of these, powered, and in the direction as needed.

b) New are level converters, with dual Vccs, from TI, and IIRC Fairchild. These are a more precise solution, and will give lower Icc levels. Driving a 5V powered TTL threshold gate with >2.4V hi, works in the Logic sense, but it does draw IP buffer current, so if you are worried about static Icc, the level converters can be a better solution.

-jg

Reply to
Jim Granville

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