2 Hardware Specification

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2.1 Power Consumption

The power consumption of the Level Shifter Board depends on its configuration. The board will draw approximately 6 mA from the Adapter/Analyzer side when configured to power the target device, and approximately 4 mA when the target is supplying its own power.

The current draw of the Level Shifter Board on the Target side is only applicable when the target device is supplying power to the board. This current draw will be approximately 1 mA.

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2.2 Speed

The Level Shifter Board is rated for I2C communication at up to 800kHz.

Maximum SPI and MDIO signaling rates are highly dependent on the specific configuration of the level shifting board and the timing specification of the target device. The Level Shifter Board has been tested to operate at up to 18 MHz when shifting to 1.2 V, and up to 20 MHz when shifting to 3.3 V. When operating at higher speeds, shorter cables are recommended to help maintain signal integrity.

Please note that individual results will vary.

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2.3 I2C Pull-up Resistors

The Adapter/Analyzer side will always require pull-up resistors for I2C communication. This is easily accomplished by using the built-in pull-up resistors of either an Aardvark I2C/SPI Host Adapter or Beagle I2C/SPI/MDIO Protocol Analyzer. Additionally, any I2C line that is being used as a digital input line (GPIO) to the Adapter/Analyzer side, must also include a pull-up on the adapter side.

It is recommended that pull-up resistors are always used on the Target side I2C lines. Users may find that they can still communicate properly without these pull-ups, however it is recommended that pull-ups to the target’s logic high still be used to ensure that the signal reaches its correct level.

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2.4 Leakage Voltage

The Level Shifter Board is known to leak approximately 0.2 V to the Target side, even when configured to not supply power to the target. This is a very weak leakage which is only capable of sourcing approximately 20 µA of current.