343S00354 Main PMU IC for iPhone 11 / 11 Pro / 11 Pro Max

All three iPhone 11 models use the same main PMU part, 343S00354. That makes it one of the more useful board-level parts to keep in stock, since one chip covers the 11, 11 Pro and 11 Pro Max when a phone arrives with no power and the battery has already been ruled out.

This is the 343S00354 main power management unit for the iPhone 11, 11 Pro and 11 Pro Max, listed as OEM New Grade. The PMU brings up nearly every rail at start-up, so its failure usually means a phone that won't turn on.

Signs pointing to the PMU

• No power with a good battery and no short on the main line.

• Abnormal current draw on a bench supply at power-on.

• Missing PMU outputs while its inputs are present.

• A rail short traced to the PMU itself.

Stacked-board considerations

The iPhone 11 series uses a stacked logic board. Check which layer the PMU sits on before you start, and plan for separation and rejoining if needed. Rule out shorted capacitors and filters first, since they produce similar symptoms.

After a careful BGA replacement, check current draw and boot, then charge the phone and let it run to confirm stability.