# DDR2 interface for RTL8735B (bare SoC) -- need reference schematic/ routing rules

**URL:** <https://forum.amebaiot.com/t/ddr2-interface-for-rtl8735b-bare-soc-need-reference-schematic-routing-rules/4577>\
**Category:** Hardware\
**Tags:** evb-amb82, rtl8735b\
**Created:** [December 11, 2025, 6:33am UTC](https://forum.amebaiot.com/t/ddr2-interface-for-rtl8735b-bare-soc-need-reference-schematic-routing-rules/4577 "2025-12-11T06:33:55Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![SurajYadav](https://sea2.discourse-cdn.com/flex016/user_avatar/forum.amebaiot.com/surajyadav/32/2993_2.png) [@SurajYadav](https://forum.amebaiot.com/u/SurajYadav)\
**Post date:** [December 11, 2025, 6:33am UTC](https://forum.amebaiot.com/t/ddr2-interface-for-rtl8735b-bare-soc-need-reference-schematic-routing-rules/4577/1 "2025-12-11T06:33:55Z")

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I’m designing a board with the bare RTL8735B SoC (not the module) and must attach an external DDR2 memory(128 MB). I couldn’t find a clear RTL8735B DDR hardware guide in the public HDK.

Can anyone share:

- an RTL8735B → DDR2 pin mapping/ reference schematic
- layout rules for the DDR connections

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**Author:** ![SurajYadav](https://sea2.discourse-cdn.com/flex016/user_avatar/forum.amebaiot.com/surajyadav/32/2993_2.png) [@SurajYadav](https://forum.amebaiot.com/u/SurajYadav)\
**Post date:** [December 16, 2025, 3:28am UTC](https://forum.amebaiot.com/t/ddr2-interface-for-rtl8735b-bare-soc-need-reference-schematic-routing-rules/4577/2 "2025-12-16T03:28:23Z")

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@M-ichae-l Can you provide any resources related to this

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**Author:** ![M-ichae-l](https://sea2.discourse-cdn.com/flex016/user_avatar/forum.amebaiot.com/m-ichae-l/32/33_2.png) [@M-ichae-l](https://forum.amebaiot.com/u/M-ichae-l)\
**Post date:** [December 16, 2025, 7:00am UTC](https://forum.amebaiot.com/t/ddr2-interface-for-rtl8735b-bare-soc-need-reference-schematic-routing-rules/4577/3 "2025-12-16T07:00:19Z")

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Hi @SurajYadav thanks for choosing RTL873B for your project.

Please note that RTL8735B only supports embedded DDR (64 MB / 128 MB). It does not support external RAM, but it does support external flash.

Therefore, if you are looking for external DDR, it is unfortunately not supported. However, we do have the 128 MB embedded DDR option.

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<div class="post-metadata">

**Author:** ![SurajYadav](https://sea2.discourse-cdn.com/flex016/user_avatar/forum.amebaiot.com/surajyadav/32/2993_2.png) [@SurajYadav](https://forum.amebaiot.com/u/SurajYadav)\
**Post date:** [December 16, 2025, 10:19am UTC](https://forum.amebaiot.com/t/ddr2-interface-for-rtl8735b-bare-soc-need-reference-schematic-routing-rules/4577/4 "2025-12-16T10:19:32Z")

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Hi @M-ichae-l ,

Thank you for your response,I want to know is the DDR memory embedded in the chip(IC of 10x10 mm) or the module?

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<div class="post-metadata">

**Author:** ![M-ichae-l](https://sea2.discourse-cdn.com/flex016/user_avatar/forum.amebaiot.com/m-ichae-l/32/33_2.png) [@M-ichae-l](https://forum.amebaiot.com/u/M-ichae-l)\
**Post date:** [December 17, 2025, 2:00am UTC](https://forum.amebaiot.com/t/ddr2-interface-for-rtl8735b-bare-soc-need-reference-schematic-routing-rules/4577/5 "2025-12-17T02:00:24Z")

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> [@SurajYadav](#):
>
> Thank you for your response,I want to know is the DDR memory embedded in the chip(IC of 10x10 mm) or the module?

It is embedded with chip. (inside the IC). Thank you.