7.3 Feature Description

Each channel of the TPL7407LA consists of high power low side NMOS transistors driven by level shifting and gate driving circuitry. The gate drivers allow for high output current drive with a very low input voltage, meaning full operation with low GPIO voltages.

In order to enable floating inputs a 1-MΩ pull-down resistor exists on each channel. Another 50-kΩ resistor exists between the input and gate driving circuitry. This exists to limit the input current whenever there is an over voltage and the internal Zener clamps. It also interacts with the inherent capacitance of the gate driving circuitry to behave as an RC snubber to help prevent spurious switching in noisy environment.

In order to power the gate driving circuitry an LDO exists. See the Power Supply Recommendations section for further detail on this circuitry.

The diodes connected between the output and COM pin is used to suppress kick-back voltage from an inductive load that is excited when the NMOS drivers are turned off (stop sinking) and the stored energy in the coils causes a reverse current to flow into the coil supply.