Implementation of LPC1778FBD208

[olligsk]

I want to implement a LPC1778FBD208 on a PCB, I was wondering if there is a recommended circuit for the power supply and pin decoupling.

The board will be supplied through 3.3V via header pins. On other projects with other microcontrollers I always found a combination of resistors and capacitors that were recommended.

[xiangjun_rong]

Hi,

Regarding your question about the power supply decoupling capacitor, first of all, the resistor is not required, because the resistor will consume power and decrease the transient process.

I suppose this is a guide, for each power supply pin, a 0.1uF decoupling capacitor is required, which should be located as close as possible to the power supply pin of micro-controller. For the DC bus for example 5V or 3.3V bus, a large decoupling capacitor is required, but it is dependent on the consumed current,  the more the current is, the more the capacitor is. Based on experience, 1A current of DC bus corresponds to 10uF cap, so 2A current corresponds to 20uF cap. The capacitor can be tantalum capacitor or ceramic capacitor generally.

Hope it can help you

BR

XiangJun Rong

[xiangjun_rong · Accepted solution]

Hi, Oliver,

This is the schematics of the LPC1769, pls refer to it.

BR

XiangJun Rong