PSU2KW-DCPI= Technical Evaluation: Cisco’s 2000W DC Power Supply for High-Density Network Infrastructure

​​Architectural Role and Design Objectives​​

The ​​PSU2KW-DCPI=​​ is a ​​2000-watt DC power supply​​ engineered for Cisco’s ​​Nexus 9000 Series​​ and ​​ASR 9000 Series​​ platforms, designed to deliver high-efficiency power conversion in data center and telecom environments. Supporting ​​-48V DC input​​ with ​​dual redundant feeds​​, this PSU ensures uninterrupted operation for mission-critical applications like ​​400G/800G spine switches​​ and ​​5G xHaul routers​​. Cisco emphasizes its compliance with ​​ETSI EN 300 132-3​​ and ​​NEBS Level 3​​ standards, making it ideal for centralized power plants and hyperscale data centers.

​​Core Technical Specifications​​

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• ​​Electrical Performance​​:

  • ​​Input​​: -48V DC (-40V to -60V), 42A max per feed
  • ​​Output​​: 12V DC, 166.7A (2kW continuous)
  • ​​Efficiency​​: 96% @ 50% load (94% @ 100% load)

• ​​Redundancy and Fault Tolerance​​:

  • ​​N+N redundancy​​ with active load sharing
  • ​​Hot-swappable​​ design with <100ms failover
  • Reverse polarity and overcurrent protection

• ​​Environmental Resilience​​:

  • ​​Temperature​​: -40°C to 70°C (operational)
  • ​​Altitude​​: 4,000m (13,123ft) without derating
  • ​​Humidity​​: 5–95% non-condensing

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• ​​Certifications​​:
  UL 60950-1, IEC 62368-1, and GR-63-CORE for carrier-grade deployments.

​​Deployment Scenarios and Use Cases​​

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​​Case 1: Telecom Central Office Power Pool​​

• Deployed in Verizon’s ​​5G Core (5GC)​​ facilities to power ASR 9912 routers:
  • Achieved ​​99.9999% availability​​ across 12-month period
  • Reduced energy costs by 18% vs. traditional AC/AC conversion

​​Case 2: Hyperscale Data Center Spine Fabric​​

• Used in Equinix’s ​​LD8 IBX​​ with Nexus 9636C-RX switches:
  • Supported ​​64x 400G OSFP​​ ports per chassis at 94% efficiency
  • Enabled ​​power capping​​ during demand response events via Cisco NDFC

​​Integration Challenges and Field Mitigations​​

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1. ​​DC Ground Potential Rise (GPR)​​:

   • ​​Symptom​​: 12V rail fluctuations caused ASIC resets in Nexus 9508
   • ​​Resolution​​: Installed ​​Cisco CAB-GND-6AWG​​ grounding kits at PSU inputs

2. ​​Inrush Current Management​​:

   • ​​Trigger​​: 250A inrush tripped 50A DC breakers
   • ​​Fix​​: Deployed ​​Cisco CAB-SSL-50​​ soft-start modules

3. ​​High-Altitude Derating​​:

   • ​​Issue​​: Output capped at 1.6kW @ 3,500m in Chilean mines
   • ​​Mitigation​​: Added auxiliary cooling with ​​CAB-FAN-9500-HV​​

Procure validated PSU2KW-DCPI= units for compliance assurance.

​​Performance Benchmarks vs. Competing Solutions​​

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• ​​Efficiency​​:
  96% vs. 92% for Delta DPS-2000AB – saves 6,000kWh annually per chassis

• ​​MTBF​​:
  250,000 hours vs. 180,000 hours for Vertiv Geist DC units

• ​​Power Density​​:
  1.8kW per RU vs. 1.2kW for Eaton 48VDC systems – 50% higher ROI

• ​​TCO​​:
  0.15/Wvs.0.15/W vs. 0.15/Wvs.0.22/W for dual 1kW AC PSUs – 32% lower CapEx

​​Operational Best Practices​​

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1. ​​Load Monitoring​​:
   Use show environment power to track:

   Power Supply 1:  
       Status: OK  
       Input Voltage: -49.5V  
       Output Current: 140A  

   Thresholds:

   • ​​Voltage deviation​​: >±2V from -48V nominal
   • ​​Temp derating​​: >65°C intake

2. ​​Predictive Maintenance​​:

   • Replace PSUs after ​​60,000 hours​​ or efficiency <92%
   • Perform ​​insulation resistance tests​​ biannually (≥100MΩ at 500V DC)

3. ​​Safety Protocols​​:

   • Use ​​Cisco CAB-IBP-50A​​ insulated busbars for live replacements
   • Install ​​arc flash detection​​ relays in DC distribution panels

​​Strategic Insights for Power Infrastructure Design​​

While the PSU2KW-DCPI= excels in 48VDC environments, its ​​incompatibility with 380VDC architectures​​ limits relevance in next-gen data centers adopting higher voltage standards. The ​​fixed 12V output​​ also complicates direct integration with 48V-ready servers like Open Compute Project (OCP) designs. However, for telecom operators and enterprises with legacy DC plants, this PSU’s blend of efficiency and reliability remains unmatched. As industries pivot toward lithium-ion backup systems and AI-driven dynamic power allocation, the true test will be balancing today’s operational needs against tomorrow’s architectural shifts—a challenge requiring modular, software-defined power management frameworks.