SPRAD06B
March 2022 – November 2024
AM620-Q1
,
AM623
,
AM625
,
AM625-Q1
1
Abstract
Trademarks
1
Overview
1.1
Board Designs Supported
1.2
General Board Layout Guidelines
1.3
PCB Stack-Up
1.4
Bypass Capacitors
1.4.1
Bulk Bypass Capacitors
1.4.2
High-Speed Bypass Capacitors
1.4.3
Return Current Bypass Capacitors
1.5
Velocity Compensation
2
DDR4 Board Design and Layout Guidance
2.1
DDR4 Introduction
2.2
DDR4 Device Implementations Supported
2.3
DDR4 Interface Schematics
2.3.1
DDR4 Implementation Using 16-Bit SDRAM Devices
2.3.2
DDR4 Implementation Using 8-Bit SDRAM Devices
2.4
Compatible JEDEC DDR4 Devices
2.5
Placement
2.6
DDR4 Keepout Region
2.7
DBI
2.8
VPP
2.9
Net Classes
2.10
DDR4 Signal Termination
2.11
VREF Routing
2.12
VTT
2.13
POD Interconnect
2.14
CK and ADDR_CTRL Topologies and Routing Guidance
2.15
Data Group Topologies and Routing Guidance
2.16
CK and ADDR_CTRL Routing Specification
2.16.1
CACLM - Clock Address Control Longest Manhattan Distance
2.16.2
CK and ADDR_CTRL Routing Limits
2.17
Data Group Routing Specification
2.17.1
DQLM - DQ Longest Manhattan Distance
2.17.2
Data Group Routing Limits
2.18
Bit Swapping
2.18.1
Data Bit Swapping
2.18.2
Address and Control Bit Swapping
3
LPDDR4 Board Design and Layout Guidance
3.1
LPDDR4 Introduction
3.2
LPDDR4 Device Implementations Supported
3.3
LPDDR4 Interface Schematics
3.4
Compatible JEDEC LPDDR4 Devices
3.5
Placement
3.6
LPDDR4 Keepout Region
3.7
LPDDR4 DBI
3.8
Net Classes
3.9
LPDDR4 Signal Termination
3.10
LPDDR4 VREF Routing
3.11
LPDDR4 VTT
3.12
CK0 and ADDR_CTRL Topologies
3.13
Data Group Topologies
3.14
CK0 and ADDR_CTRL Routing Specification
3.15
Data Group Routing Specification
3.16
Byte and Bit Swapping
4
LPDDR4 Board Design Simulations
4.1
Board Model Extraction
4.2
Board-Model Validation
4.3
S-Parameter Inspection
4.4
Time Domain Reflectometry (TDR) Analysis
4.5
System Level Simulation
4.5.1
Simulation Setup
4.5.2
Simulation Parameters
4.5.3
Simulation Targets
4.5.3.1
Eye Quality
4.5.3.2
Delay Report
4.5.3.3
Mask Report
4.6
Design Example
4.6.1
Stack-Up
4.6.2
Routing
4.6.3
Model Verification
4.6.4
Simulation Results
5
Appendix: AM62x ALW and AMC Package Delays
6
Revision History
Application Note
AM62x DDR Board Design and Layout Guidelines