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TIOS101: Meaning of residual voltage

Part Number: TIOS101
Other Parts Discussed in Thread: TIOS102, UCC27517

What does residual voltage mean for the TIOS101? We will be using it in push-pull mode. Does is means the output will not drive all the way to 0V when the input is high? We want to use the TIOS101 because of its faster output rise/fall times but the TIOS102 advertises a lower residual voltage and we're trying understand if that will be important.



  • Figures 6-2/6-3 show that the TIOS101 output does not go to 0 V; there appears to be a diode in the path. The TIOS102 does have a rail-to-rail output.

    Another method to get a strong, high-voltage output is a gate driver like the UCC27517.

  • Hi Ben,

    The voltage drop between the two pins in the current path is referred to as the "Residual Voltage" and comes from the ON resistance (Ron) of the transistors and any other elements such as reverse polarity protection diodes that are in series with the drive transistors. 

    The reason residual voltage is of concern is that it is one of the primary sources for power dissipation and thermal heating in the device.  A lower residual voltage drop inside the device will result in a lower power dissipation and a lower die junction temperature.  The TIOS102 will therefore have an advantage over the TIOS101 for applications that needed to drive a large load, and or in applications that operate with a high ambient temperature.

    The primary difference between the TIOS101 and TIOS102 with regards to the Residual Voltage is that the TIOS101 has fixed reverse polarity protection diodes and the TIOS102 has an active circuit that monitors for a reverse polarity condition and disable the driver.  In both device types there will be some voltage drop across the transistors due to the ON Resistance and be proportional to to the amount of current flowing, but the TIOS101 has an additional voltage drop across the diode which does prevent the OUT pin from reaching a hear 0V or GND level.

    Please refer to the Functional Block Diagrams for the two devices to see the difference between the two architectures.  You can see the fixed polarity protection diodes in the TIOS101 are replaced with a Reverse Polarity Protection active circuit block in the TIOS102.

    Also there are example waveforms provided in the datasheet for your reference.  Figure 9-4 in the TIOS101 datasheet shows there is a slight voltage offset between the VOL and GND (0V).  The TIOS102 does not have the same waveform for side-by-side comparison, but Figure 9-8 does show that the OUT voltage does not have this voltage offset and is at the GND (0V) level.



  • Excellent, thank you!