DDR5 DIMM Protection
On-module protection and power for DDR5 memory modules: client CUDIMM and CSO-DIMM, server RDIMM, and DDR5 CAMM2.
DDR5 moved power conversion from the motherboard onto the memory module. Every DDR5 module now carries its own PMIC, fed by a VIN_BULK rail that enters at the connector, a surge and ESD target that DDR4 modules did not have. Magnias supplies the TVS diodes, chip fuses, LDO and small-signal MOSFET parts that protect and support this on-module power tree on the three module families covered here: client CUDIMM and CSO-DIMM (desktop and notebook, PMIC5100 or PMIC5120), server RDIMM (PMIC5000 to PMIC5030), and DDR5 CAMM2 (notebook and desktop, 5V client PMIC).
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 the motherboard (board regulators feed all DIMMs) | On each DIMM (every module has its own PMIC) |
| VIN to the DIMM | Final rails (VDD 1.2V, VPP 2.5V) from motherboard regulators | Higher-voltage rail (5V or 12V), VIN_BULK, converted on-module |
| Surge exposure on the module | Low, only 1.2V to 2.5V rails enter the module | 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 (no PMIC on the module) | PMIC5100 / PMIC5120 (client), PMIC5000 to PMIC5030 (server) |
DDR5 PMIC overview
JEDEC defines several PMIC types for DDR5 modules: PMIC5100 and PMIC5120 for client modules, and PMIC5000, PMIC5010, PMIC5020 and PMIC5030 for server modules. The VIN_BULK voltage is the key difference, and it decides which TVS to use.
DDR5 DIMM block diagrams
Choose a DIMM type to see the protection and power architecture. Tap any Magnias-coverage block (blue) 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 a JEDEC client PMIC (PMIC5100 or PMIC5120) running off a 5V VIN_BULK rail from the connector. Modules with RGB lighting add an LDO and a MOSFET for the LED driver.
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 Input Fuse (2A) | MGF04F-2000A | 0402 | DDR5 CAMM2 | Fast-acting thick-film chip fuse. 2A rated current, 32V DC, 35A breaking capacity. |
| 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" |
| RGB LED power LDO (500 mA) | PR9050-ADS5 | SOT23-5L | CUDIMM with RGB (optional) | Supply for the RGB LED driver. 500 mA, 1.5 µA IQ (typ). Datasheet application line: "DDR5 CU-DIMM RGB LED Driver power" |
| RGB LED switch MOSFET | PMT14DN02ATW | SOT363 | CUDIMM with RGB (optional) | Dual N-channel MOSFET (N+N), 20V, 0.9A. Datasheet application line: "DDR5 CU-DIMM RGB LED Driver Switching Circuit" |
Request samples or a DDR5 protection review
Designing a DDR5 module? Need samples of the TVS, fuse, LDO or 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.