MultiMediaCard (MMC) vs. SD Bus Interfaces
Comparing 2 standards across 13 specifications. 13 key differences identified.
MultiMediaCard (MMC) is a solid-state memory card standard introduced in 1997 by Siemens and SanDisk based on a 7-pin serial bus. Evolving into RS-MMC and MMCmobile, it formed the physical and protocol foundation of both the SD card and JEDEC eMMC (embedded MultiMediaCard), the ubiquitous internal storage standard for mobile devices, smart TVs, and single-board computers.
SD Bus Interfaces define the physical and electrical signaling architectures through which SD and microSD cards transfer data with host controllers. Spanning legacy Default/High Speed, Ultra High Speed tiers (UHS-I up to 104 MB/s, UHS-II up to 312 MB/s, UHS-III up to 624 MB/s), and PCIe/NVMe-based SD Express (up to 3,940 MB/s).
Specification Comparison Table
13 Parameters| Parameter / Spec | ||
|---|---|---|
|
Governing Standards Bodies
|
MMCA (historically) / JEDEC (eMMC Standard JESD84-B51A) | — |
|
Introduction Year
|
1997 (Siemens & SanDisk) | — |
|
Physical Dimensions (Full MMC)
|
32.0 mm × 24.0 mm × 1.4 mm (7-pin interface) | — |
|
Reduced Size Formats
|
RS-MMC (24.0 × 18.0 × 1.4 mm), MMCmobile (dual voltage), MMCmicro (14.0 × 12.0 × 1.1 mm) | — |
|
Embedded Evolution
|
eMMC (eMMC 4.5, 5.0, 5.1 delivering up to 400 MB/s via 8-bit parallel bus in BGA packaging) | — |
|
Bus Widths
|
1-bit (legacy MMC), 4-bit (MMC Plus), 8-bit (eMMC HS400) | — |
|
Operating Voltages
|
3.3V (standard) / 1.8V (dual voltage / eMMC) | — |
|
Default Speed (DS) / High Speed (HS)
|
— | 12.5 MB/s (25 MHz @ 3.3V) / 25 MB/s (50 MHz @ 3.3V) |
|
UHS-I (SD 3.01)
|
— | SDR12 (12.5 MB/s), SDR25 (25 MB/s), SDR50 (50 MB/s), DDR50 (50 MB/s), SDR104 (104 MB/s @ 208 MHz 1.8V) |
|
UHS-II (SD 4.0)
|
— | 156 MB/s (Full Duplex) / 312 MB/s (Half Duplex) via 2nd pin row LVDS (0.26V) |
|
UHS-III (SD 6.0)
|
— | 312 MB/s (Full Duplex) / 624 MB/s (Full Duplex dual-lane LVDS) |
|
SD Express (SD 7.0 / 8.0)
|
— | 985 MB/s (PCIe 3.0 x1), 1970 MB/s (PCIe 4.0 x1 / 3.0 x2), up to 3940 MB/s (PCIe 4.0 x2) |
|
SD Express Protocol Stack
|
— | PCI Express (PCIe) + NVM Express (NVMe v1.3/1.4) over SD pins |