400G VR4 QSFP112 OM4 850nm 50m MPO-12 Ethernet/InfiniBand Transceiver, MSA Compliant
The VQ-4CVR4CP-AA is a 400G QSFP112 VR4 optical transceiver for short-reach AI data center connections. It supports 4x 106.25 Gb/s PAM4 lanes over multi-mode fiber with VCSEL technology, delivering 400 Gb/s aggregate throughput up to 50m on OM4 (30m on OM3) via an MPO-12 APC connector. The QSFP112 form factor provides the smallest power and thermal footprint at 400G.
Primary use case: NIC-side endpoint in 800G-VR8 to 2x 400G-VR4 breakout topologies from OSFP-based NVIDIA switches into ConnectX-7 NICs in 400G mode. Compliant with QSFP112 MSA and IEEE 802.3ck.
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- Features
- Specifications
- Applications
- FAQs
- Datasheet
- 400 Gb/s aggregate data rate (4x 106.25 Gb/s PAM4)
- QSFP112 form factor with integrated heat dissipation
- Up to 50m on OM4 / 30m on OM3 multi-mode fiber
- MPO-12 APC optical interface (8-fiber active)
- VCSEL transmitter and PIN photodiode receiver
- Designed as NIC-side endpoint of 800G-to-400G breakouts
- Validated with NVIDIA ConnectX-7 in 400G mode
- Compliant with QSFP112 MSA, IEEE 802.3ck, CMIS 5.0
- Full DDM telemetry over two-wire serial interface
- Single 3.3 V supply; Maximum power 9 W
- Commercial temperature 0 to 70 degC; RoHS 2
- US-based engineering support from New Jersey HQ
| Category | Optical Transceiver |
|---|---|
| Form Factor | QSFP112 |
| Data Rate | 400 Gb/s (4x 106.25 Gb/s PAM4) |
| Wavelength | 850 nm |
| Fiber Type | OM4 / OM3 Multi-Mode Fiber |
| Distance | 50m (OM4) / 30m (OM3) |
| Connector | MPO-12 APC (female on cable side) |
| Protocol | Ethernet, InfiniBand |
| Optics | VCSEL TX / PIN PD RX |
| FEC | RS(544,514) host-side |
| Management | CMIS 5.0, DDM |
| Power Supply | 3.3 V single supply |
| Max Power | 9 W max |
| Temperature | Commercial (0 to 70 degC) |
| Compliance | QSFP112 MSA, IEEE 802.3ck, CMIS 5.0, RoHS 2 |
Q: What is the 400G QSFP112 VR4 used for?
A: Most commonly as the NIC-side endpoint of an 800G-VR8 to 2x 400G-VR4 breakout from an OSFP-based switch. It plugs into a ConnectX-7 NIC or BlueField-3 DPU configured for 400G-VR4 mode, with an MPO-12 APC fiber assembly back to the switch.
Q: How does QSFP112 differ from QSFP-DD at 400G?
A: QSFP112 uses 4 high-speed electrical lanes at 106.25 Gb/s PAM4 for 400G total. QSFP-DD uses 8 lower-speed lanes for the same 400G. QSFP112 is smaller, lower power, and lower cost at 400G. QSFP-DD is the right pick if you need backward compatibility with 100G/200G QSFP modules.
Q: Is this directly compatible with NVIDIA switches?
A: NVIDIA Spectrum-4 / Quantum-2 / Quantum-X800 switches use the OSFP form factor at 400G+. QSFP112 is typically used on the NIC side (ConnectX-7) of an 800G-to-2x-400G breakout. For switch-side 400G on NVIDIA, use the Vitex 400G OSFP-RHS VR4 instead.
Q: What fiber type and connector should I use?
A: OM4 multi-mode fiber, MPO-12 APC connectors, Type B polarity for parallel optics, female (unpinned) on both ends. See the Vitex M12FOM4-B2 or M12F2M12FOM4-B2 breakout assemblies.
Q: What is the link loss budget?
A: 400G-VR4 has a per-lane budget of ~1.9 dB on OM4. For a 50m run with two MPO-12 APC connectors (~0.35 dB each) and fiber attenuation (~0.15 dB), expected total loss is ~0.85 dB - well within budget. Clean endfaces before mating.
Q: When should I choose VR4 over DR4?
A: VR4 for 50m or shorter on multi-mode fiber (most common in compact AI clusters). DR4 for up to 500m on single-mode fiber (typical for row-to-row connections). The choice depends on the fiber infrastructure already deployed and the run length.
Q: Why source 400G optics from Vitex?
A: Contact Vitex engineering for details on this configuration.
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