How many MB of BRAM are on a UltraScale FPGA?

The amount of Block RAM (BRAM) in UltraScale FPGAs varies significantly across the product family. Here's a detailed breakdown:

UltraScale BRAM Overview
Basic BRAM Unit: 36Kb block (can be configured as two independent 18Kb blocks)

Organization: All UltraScale devices use 36Kb BRAM primitives (RAMB36E2)

BRAM Capacity by Device Family
1. UltraScale (Standard) FPGAs

2. UltraScale+ FPGAs (Higher Density)

3. UltraScale+ MPSoCs (with Processing System)

Key Technical Notes

1. Effective Capacity:

Each 36Kb block can store:

• 36Kb × 1 (deep narrow memory)
• 18Kb × 2 (when split)
• Various width configurations (×1, ×2, ×4, ×9, ×18, ×36)

1. UltraRAM (in some UltraScale+ devices):

• Additional high-density memory (288Kb blocks)
• Not counted in BRAM totals above
• Example: XCZU19EG has 32.4 Mb BRAM + 108 Mb UltraRAM

1. Configuration Options:

• Can be initialized during configuration
• Supports ECC in some configurations
• Cascadable for wider/deeper memory

How to Check for Your Specific Device

1. In Vivado:

tcl report_property [get_parts <your_part>] 

Look for "BLOCK_RAM" properties

1. In documentation:

• Consult the "UltraScale Architecture Configurable Logic Block" (UG574)
• Or the specific device datasheet