Texas Instruments recommends a 2-layer or 4-layer PCB with a solid ground plane on the bottom layer to improve thermal performance. Additionally, it's recommended to have a minimum of 2 oz copper thickness and to use thermal vias to connect the exposed pad to the ground plane.
The UCD7138DRSR has a power-on reset (POR) circuit that ensures the device is properly powered up and configured during startup. It's recommended to follow the power-up sequencing guidelines in the datasheet and to use a slow-rising power supply to ensure the device is properly configured.
The recommended input capacitance value for the VIN pin is 10 uF to 22 uF, with an ESR of less than 1 ohm. This helps to filter out noise and ensure stable operation.
To troubleshoot issues with the device not turning on or not regulating properly, check the input voltage, output voltage, and enable pin (EN) to ensure they are within the recommended operating ranges. Also, check for any short circuits or open circuits on the PCB and ensure that the device is properly soldered.
The maximum junction temperature (TJ) that the UCD7138DRSR can operate at is 150°C. It's recommended to ensure that the device is operated within the recommended operating temperature range to ensure reliable operation and to prevent thermal shutdown.
UCD7138DRSR datasheet
by Texas Instruments
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