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What should I do when I want to sample a 5V sensor using a 3.3V MCU

I want to get the output of SCA60C using the ADC of LPC1114.SCA60C is a 5V chip while LPC1114 is a 3.3V MCU. what should I do to put them together?

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Check this comment post by OddBot , assuming you want to convert the "digital" voltages to the right levels

http://letsmakerobots.com/node/8276#comment-26083

If its the analoge voltage you want to sample - simply use a resistor divider ie two (10K or 100K) resistors spanned across the output of your 5V out device and tap the voltage off the middle node of the resistors this will give you half voltage to your 3.3V device.

Check the range of your Mpu adc and you can even adjust the two resistors to get maximum range...

But it cannot solve the impedance problem.The ADC should have a input impedance less than 40K, and the load of the sensor must bigger then 20K. it is hard to choose a good resistor divider. A 20K and 10K maybe do work,but it will take more time of ADC and will affect its accuracy

The only other suggestion is to buffer it with an opamp....... then you can scale it without worrying about impedances.

NB. the accelerometer will have speed implications (sample loop) anyways......

Relay, transistor or power mosfet?