DDR5 DIMM Protection
On-module power and protection for DDR5 — from client CUDIMM to server RDIMM to mobile CAMM2.
DDR5 moved the PMIC from the motherboard onto the DIMM itself. Every memory module now has its own power conversion stage and a VIN_BULK rail exposed at the connector — a new surge and ESD target that DDR4 never had. Magnias supplies the TVS, LDO and small-signal MOSFET parts that protect and support this on-module power tree across all three current DDR5 form factors: CUDIMM/CSO-DIMM (client desktop, PMIC5100), RDIMM (server, PMIC5020/5030), and CAMM2 (mobile/edge, PMIC5100).
DDR4 vs DDR5 — what changed for protection
The single biggest architectural change in DDR5 is where the PMIC sits. This is what creates the new protection requirement on every module.
| Topic | DDR4 | DDR5 |
|---|---|---|
| PMIC location | On motherboard (one PMIC powers all DIMMs) | On each DIMM (every module has its own PMIC) |
| VIN to the DIMM | Low-voltage rails (~1.2V) directly from motherboard PMIC | Higher-voltage rail (5V or 12V) — VIN_BULK — converted on-module |
| Surge exposure on the module | Minimal — only signal-level interface | Significant — full VIN_BULK rail entering the module |
| Required on-DIMM TVS | Not required | Required on VIN_BULK (and VIN_MGMT on server) |
| JEDEC PMIC standard | n/a (PMIC is motherboard-vendor specific) | PMIC5100 (client), PMIC5020 / PMIC5030 (server) |
DDR5 PMIC overview
JEDEC defines three PMIC classes for DDR5 modules — one for client and two for server. The VIN_BULK voltage is the key differentiator that determines which TVS to use.
DDR5 DIMM block diagrams
Choose a DIMM type to see the protection and power architecture. Tap any Magnias-coverage block (green) for recommended parts.
CUDIMM is the DDR5 client memory module for desktops, with an on-module clock driver (CKD) added compared to UDIMM. CSO-DIMM is the same architecture in the small SO-DIMM form factor for notebooks. Both use the JEDEC PMIC5100 client PMIC running off a 5V VIN_BULK rail from the connector.
Magnias DDR5 part summary
| Function | Magnias P/N | Package | Applies to | Notes |
|---|---|---|---|---|
| 12V Input Fuse (7A) | MGF06F-7000A | 0603 | RDIMM — GEN5 rev 2 (A2/C2/D2/E2) | Fast-acting thin-film chip fuse. 7A rated current for newer GEN5 RDIMM rev 2 designs. |
| 12V Input Fuse (6A) | MGF06F-6000A | 0603 | RDIMM — earlier rev 0 / rev 1 | Fast-acting thin-film chip fuse. 6A rated current for older RDIMM rev 0/1 (A0/C0/D0/E0, A1/C1/D1/E1). |
| 5V VIN_BULK TVS | PS0512N-F4 | DFN1006-2L | CUDIMM / CSO-DIMM / CAMM2 | Datasheet application line: "DDR5 CU/CSO-DIMM 5V VIN_BULK Protection" |
| 12V VIN_BULK TVS | PT1284Y-F6 | DFN1610-2L | RDIMM | Datasheet application line: "DDR5 R-DIMM 12V VIN_BULK Protection" |
| 3.3V VIN_MGMT TVS | PS0310G-F4 | DFN1006-2L | RDIMM | Datasheet application line: "DDR5 R-DIMM 3.3V VIN_MGMT Protection" |
| Low-IQ LDO (300 mA) | PR9030-3V3S5 | SOT23-5L | All DIMMs (optional) | 300 mA, 0.5 µA IQ — for SPD Hub auxiliary rail |
| Higher-current LDO (500 mA) | PR9050-ADS5 | SOT23-5L | All DIMMs (optional) | 500 mA, 1.5 µA IQ — for heavier auxiliary loads |
| RGB LED driver MOSFET | PMT14DN02ATW | SOT-563 | CUDIMM / CAMM2 (ARGB) | Small-signal N-ch MOSFET for ARGB LED switching |
Request samples or a DDR5 protection review
Designing a DDR5 module? Need samples of the TVS / LDO / MOSFET parts above, or want our FAE team to review your DIMM protection layout? Tell us the form factor and the parts of interest — we reply within one business day.