STM32F407 RAM Interface impedance matching

ashutosh211 · ‎2025-11-14

Hi Team,

As we are going to use RAM – IC CY62136EV30 (TSOP-44) in our new project with ST micro STM32F407ZG (LQFP-144).

Do we need any impedance matching for 6-layer board?

Can you please suggest the same. Crystal frequency we taken 16MHz for the MCU.

Thanks.

Regards,

Ashutosh

TDK · ‎2025-11-14

Having short traces is most important.

Then length matching. Differences up to a couple cm are generally fine.

Then impedance matching. If traces are short, this matters very little.

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ashutosh211 · ‎2025-11-15

Thanks for the feedback!

I mean do we need any series resistance (22E or 33E) to be added in data & address line or only shorter distance is enough with length matching on PCB routing? Kindly suggest the same.

ashutosh211 · ‎2025-11-19

Hi Team,

Can you please confirm on above mentioned?

Thanks.

Regards,

Ashutosh

STOne-32 · ‎2025-11-22

Dear @ashutosh211 ,

You can check our Application Note AN4803

”High-speed SI simulations using IBIS and board-level simulations using HyperLynx® SI on STM32 MCUs and MPUs”

all depends on your Frequency speed of clock and data of the RAM I/F.
Hope it helps you ,

STOne-32