800 VDC to 50 VDC DC Power Shelf // 15 kW Hot-Swappable DC-DC PSU Modules
90 kW of 800 VDC to 50 VDC Power for AI Rack Infrastructure
AI Infrastructure Power // 800 VDC
PRELIMINARY — specifications subject to change
DX8-90: 800 VDC to 50 VDC at the rack, 90 kW per shelf
The DX8-90 is the stage that makes 800 VDC distribution usable at the server. It converts an
800 VDC bus into regulated 50 VDC at the rack, delivering up to 90 kW from six 15 kW hot-swappable DC-DC modules at
up to 98.5% efficiency. Each module shares current independently and can be added in 15 kW increments as rack load
grows.
Why convert at the rack
Delivering 90 kW at 50 VDC from a central source would put 1800 A on the full run into the rack.
Converting at the rack instead keeps that current inside the shelf busbar, while the feed into the rack carries
112 A at 800 VDC — the same power at one sixteenth the current. Conductor loss scales with the square of
current for a given cross-section.
The 800 VDC power chain. The high-current path is confined to the DX8-90 shelf busbar.
into the 800 VDC bus — 110 kW from six 18.5 kW PSU modules, with optional LFP battery ride-through in the 7U
AX8E-110.
One shelf, one rack
The DX8-90 pairs one-to-one with an AX8-110 or AX8E-110, connected directly with no intermediate
PDU or bus. The 800 VDC input connector matches the output connector on the upstream shelf.
The capacity difference between the two is deliberate. A 110 kW upstream shelf feeding a 90 kW
downstream load means five PSU modules carry the 90 kW load at 18 kW each, inside their 18.5 kW rating, and the sixth is spare — module-level 5+1
redundancy across the pair, without a separate redundant shelf.
AX8-110 / AX8E-110
AC to 800 VDC conversion and, where specified, battery ride-through. Sits in the
sidecar power rack alongside other shelves.
DX8-90
800 VDC to 50 VDC conversion at the point of use. Sits in the IT rack with the compute it
serves, keeping the high-current path as short as possible.
What sets the DX8-90 apart
Where the DX8-90 sits in the 800 VDC chain
Shelf and module
| Parameter | DX8-90 |
|---|---|
| Shelf power rating | 90 kW per shelf (6 × 15 kW) |
| Redundancy | 90 kW (N+0) / 75 kW (N+1) / 45 kW (N+N) |
| Rated input voltage | 800 VDC nominal |
| Input voltage range | 750 to 850 VDC |
| Input connection | One DC input, matching the single 800 VDC output of the AX8-110. Bizlink 117G0-178308-R1, 5-wire (800 VDC + PE + signal), 112.5 A rated |
| Output voltage | 49 to 51 VDC (51 V no-load, 49 V at 100% load; 1 V droop, 2 V at 150%) |
| Ripple and noise | ±500 mV (20 MHz bandwidth) |
| Rated output current | 300 A per module; 1800 A maximum per shelf |
| Shelf output connection | Floating blind-mate connector, mates with ORv3 busbars. Liquid-cooled BarKlip termination not yet available; interim arrangement applies |
| Module rating | 15 kW per DX8-150 module |
| Modules per shelf | Up to 6 |
| Efficiency | Up to 98.5%; about 1.4 kW loss at full 90 kW output |
| Current sharing | Independent parallel current sharing |
| Hot swap | Yes, front-serviceable |
| Module protection | Over-voltage, over-current |
| Parallel operation | Intra-shelf and inter-shelf; multiple shelves paralleled for rack and row-level systems |
Shelf to rack manager
CAN carries communication between the DC-DC modules inside the shelf. The shelf itself connects by
RJ45 to the top-of-rack switch, which links to the data center monitoring layer over Redfish. The same pattern
applies to the upstream AX8-110, so a single management system sees every shelf in the chain the same way.
| Parameter | DX8-90 |
|---|---|
| Controller | Power Monitoring Controller (PMC), shelf-level monitoring and control |
| Intra-shelf interface | CAN, up to 115 kbps, active by default |
| Shelf uplink | RJ45 to top-of-rack switch |
| Management layer | Redfish to the data center monitoring system |
| Telemetry | Voltage and current in and out, temperatures, fan speeds, power, serial and part number, hardware and firmware revision |
| Diagnostics | Black-box fault logging |
Rack integration
| Parameter | DX8-90 |
|---|---|
| Shelf dimensions | 839.5 × 448 × 43.6 mm (D × W × H) |
| Shelf rack height | 1U |
| Shelf weight | 32 kg populated; 8.5 kg empty |
| Module dimensions (W × H × D) | 68 × 40 × 710 mm |
| Auxiliary output | 12 VDC / 1 A |
| Module I/O connector | Molex 2141150098-SD or equivalent, blind-mate |
| Rack compatibility | 19-inch EIA-310 |
| Rack placement | IT rack, alongside the compute it serves |
| Operating temperature | 5 to +45°C |
| Thermal behavior | Over-temperature protection engages on sensor detection; no linear output derating |
| Humidity | 8 to 85%, non-condensing |
| Operating altitude | 3050 m (10,000 ft) |
| Acoustic noise | Target not to exceed 95 dB with fans at full speed (design target, not a measured figure) |
Standards
Expected environmental compliance: RoHS, REACH, Halogen-Free (IEC 61249-2-21) and WEEE. The final list is pending output connector selection and will be confirmed when the shelf termination is finalized.
Documentation
Designing an 800 VDC rack?
The DX8-90 is in development. We are working with infrastructure teams now
on reference configurations, and can share current specifications and timelines under NDA.