JAJSLK5B October 2020 – May 2022 LMG3422R050 , LMG3425R050
PRODUCTION DATA
The LMG342xR050 allows users to adjust the drive strength of the device and obtain a desired slew rate, which provides flexibility when optimizing switching losses and noise coupling.
To adjust drive strength, a resistor can be placed between the RDRV pin and GND pin. The resistance determines the slew rate of the device, from 20 V/ns to 150 V/ns, during turn-on. On the other hand, there are two dv/dt values that can be selected without the resistor: shorting the RDRV pin to ground sets the slew rate to 150 V/ns, and shorting the RDRV pin to LDO5V sets the slew rate to 100 V/ns. The device detects the short to LDO5V one time at power up. Once the short to LDO5V condition is detected, the device no longer monitors the RDRV pin. Otherwise, the RDRV pin is continuously monitored and the dv/dt setting can be changed by modulating the resistance during device operation. The modulation must be fairly slow since there is significant internal filtering to reject switching noise.
Please note: parasitic power loop inductance can influence the voltage slew rate reading from the VDS switching waveform.The inductance induces a drop on VDS in the current rising phase before voltage falling phase, if this drop is more than 20% of the VDC, the voltage slew rate reading can be influenced. Refer to Section 12.1.2 for the power loop design guideline and how to estimate the parasitic power loop inductance.