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From time to time the level shift module pictured above has come in handy. They do a great job shifting 3.3VDC to 5VDC logic or 5VDC logic to 3.3VDC logic. The cost is about $1USD and hookup is simple. Of course they are designed for low speed digital signals but, we wondered how the module would handle higher speeds.
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The Bench Setup:
Keithley 2230G-30-1 power supply for the 3.3VDC and 5VDC power.
Tektronix AFG3252C function generator for the square wave (3.3V and 5V logic) stimulus.
Tektronix MDO4104C oscilloscope to capture the input/output signals.
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The Result:
Performance was very good, especially considering these module are often used in the 100KHz and below range. Leveling from 5V to 3.3V had better results. The signals start looking ridiculous over 1MHz. Take a look at the scope shots below.
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3.3V Level Shifted to 5V at 10KHz, 100KHz, 500KHz, and 1MHz
(Yellow = Input; Blue = Output)
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5V Level Shifted to 3.3V at 10KHz, 100KHz, 500KHz, and 1MHz
(Yellow = Input; Blue = Output)
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