# What is VDD in this context?

On this page, the two versions of this gyro/accelerometer IC have two different Logic Supply Voltages.

What is the VDD voltage?

Why would one version of the chip also have an option to make the voltage 1.8V?

http://invensense.com/mems/gyro/mpu6000.html

note: not intended to be a dupe of What is the difference between $V_{CC}$, $V_{DD}$, $V_{EE}$, $V_{SS}$.

$V_{DD}$ is the supply voltage (i.e. the main voltage "in" to power the IC).

Quote from 1st the link you posted:

VDD Supply voltage range of 2.375V–3.46V; VLOGIC (MPU-6050) at 1.8V±5% or VDD

As for why there's the 1.8V VLOGIC version? I suppose it's for those that want to interface with a 1.8V $I^2C$ bus (as opposed to, say, 3.3V SPI or $I^2C$ as you'd likely use with the non-1.8V version).

From the data sheet:

For power supply flexibility, the MPU-60X0 operates from VDD power supply voltage range of 2.375V-3.46V. Additionally, the MPU-6050 provides a VLOGIC reference pin (in addition to its analog supply pin: VDD), which sets the logic levels of its I2C interface. The VLOGIC voltage may be 1.8V±5% or VDD.