Part Number: TPS562212
Tool/software:
Hello,
I'm designing a power sequencing system using four TPS562212 devices to generate 5V, 3.3V, 1.5V, and 1.2V from a shared 12V input.
The 1.2V rail powers up first. I am using its PG (Power Good) output to enable the other three TPS562212 converters for 5V, 3.3V, and 1.5V.
- The PG pin is **open-drain** and is **not pulled up externally**.
- It is **directly connected** to the EN pins of the other converters.
- Each EN pin has a **100pF ceramic capacitor to GND** for noise filtering.
Here's the connection diagram:
My intent is to keep the design simple while still ensuring reliable EN activation and noise immunity.
### Questions:
1. Is it acceptable to leave the PG pin **without a pull-up resistor** when connecting directly to EN pins?
_(I intentionally avoided a pull-up to 1.2V because it is too close to the EN Vih threshold of 1.2V, which might result in unreliable enabling.)_
2. Will the EN pins correctly detect a "high" state when PG transitions to high-impedance?
3. Is adding **100pF to GND** at each EN pin sufficient for noise immunity?
4. Is there any detailed information available on the **internal behavior or impedance** of the EN pin in TPS562212?
Any confirmation or advice would be greatly appreciated.
