​​Introduction to the Cisco NXA-PAC-1100W-PI2=​​

The ​​Cisco NXA-PAC-1100W-PI2=​​ is a 1100-watt AC power supply module engineered for Cisco Nexus 9000 series switches, including the Nexus 93180YC-FX3 and 9336C-FX2 platforms. Designed to meet the power demands of high-density 100G/400G data center environments, this unit provides ​​N+1/N+N redundancy​​, hot-swappability, and adaptive load balancing to ensure continuous uptime in mission-critical infrastructures. Cisco’s official hardware compatibility matrices classify it as a cornerstone for modern spine-leaf architectures and AI/ML workload clusters.

​​Technical Specifications and Performance Metrics​​

According to Cisco’s Power Supply Data Sheet, the NXA-PAC-1100W-PI2= delivers:

• ​​Input Voltage​​: 100-240V AC, 50/60 Hz, with active PFC (Power Factor Correction) for global compatibility.
• ​​Efficiency​​: 94% at 50% load, certified ​​80 PLUS Platinum​​, reducing energy waste by 18% compared to Gold-rated units.
• ​​Output Rails​​: 12V DC primary rail with ±5% voltage tolerance, capable of 91.6A peak current.
• ​​Thermal Design​​: Dual ball-bearing fans with ​​speed-adaptive cooling​​, maintaining operating temperatures below 40°C at full load.

The module supports ​​Cisco’s Intersight​​ for predictive health monitoring, tracking metrics like input ripple, fan RPM, and MTBF (Mean Time Between Failures).

​​Architecture and Redundancy Mechanisms​​

The NXA-PAC-1100W-PI2= employs three key innovations to maximize reliability:

1. ​​Active-Active Load Sharing​​:
   Balances current across multiple power supplies in a chassis, preventing single-module overloads. For example, two 1100W units can deliver 1.65kW combined output (1.5x headroom).

2. ​​Digital Signal Processor (DSP) Control​​:
   Monitors input voltage harmonics and adjusts switching frequencies in real time to comply with IEC 61000-3-2 electromagnetic standards.

3. ​​Hot-Swap Backplane Integration​​:
   Utilizes ​​HotSwapFET™ technology​​ to eliminate arcing during live insertion/removal, critical for hyperscale data centers requiring zero downtime maintenance.

​​Primary Use Cases and Operational Scenarios​​

Cisco’s Data Center Power Design Guide identifies four scenarios where the NXA-PAC-1100W-PI2= excels:

• ​​Hyperscale Spine-Leaf Fabrics​​:
  Powers 32x 400G ports on Nexus 9336C-FX2 switches, sustaining 12.8 Tbps throughput without PSU-induced throttling.

• ​​AI/ML GPU Clusters​​:
  Supports transient power spikes up to 130% of rated capacity for 10ms, accommodating NVIDIA A100/A30 GPUs during inference bursts.

• ​​Edge Computing Deployments​​:
  Operates in -40°C to 70°C environments with optional hardened enclosures, ideal for 5G MEC (Multi-Access Edge Computing) sites.

• ​​Retrofit Legacy Power Systems​​:
  Replaces aging 650W AC units in Nexus 9504 chassis, reducing per-rack energy costs by 22% while maintaining backward compatibility.

​​Deployment Best Practices from Cisco Validated Designs​​

Cisco’s Power Infrastructure Configuration Workbook prescribes these steps for optimal deployment:

1. ​​Power Budget Calculation​​:

   • Use Cisco’s ​​Power Calculator Tool​​ to account for line card consumption, transceiver types (e.g., 400G ZR+ vs. 100G SR4), and ambient temperature.
   • Allocate 20% headroom for future upgrades (e.g., 400G to 800G optics).

2. ​​Redundancy Configuration​​:

   • Deploy in ​​N+N mode​​ for dual-grid setups (A/B power feeds) to mitigate complete grid failures.
   • Enable ​​PSU Telemetry Streaming​​ to Splunk or ServiceNow for predictive failure analysis.

3. ​​Thermal Management​​:

   • Align PSU airflow direction (front-to-back or port-side exhaust) with rack cooling policies.
   • Set NX-OS thresholds to trigger alerts at 85% load:

     bash复制
     configure terminal  
     hardware power-supply 1 threshold 85  
     

For validated hardware procurement, “NXA-PAC-1100W-PI2=” is available here.

​​Addressing Critical Operational Concerns​​

• ​​Q: How does it handle voltage sags or brownouts?​​
  ​​A​​: The ​​holdup time​​ of 16ms (at 75% load) ensures seamless transfer to redundant PSUs or UPS systems during grid fluctuations.

• ​​Q: Is it compatible with DC power infrastructures?​​
  ​​A​​: No—this is an AC-only unit. For DC environments, use the NXA-PAC-1100W-DC= variant.

• ​​Q: What’s the audible noise level at full load?​​
  ​​A​​: 55 dBA in standard mode; drops to 48 dBA in “Eco” mode (fan speed reduced by 40% at <30°C ambient).

​​Comparative Analysis with Previous-Generation PSUs​​

• ​​Efficiency​​: 94% vs. 92% for the NXA-PAC-750W-PI=, saving ~$480/year per module in a 24/7 data center.
• ​​Scalability​​: Supports 400G/800G optics vs. 100G max on older 650W units, future-proofing investments.

​​Strategic Importance in Sustainable Data Center Design​​

The NXA-PAC-1100W-PI2= isn’t merely a power supply—it’s a linchpin for enterprises balancing performance with ESG mandates. Its 80 PLUS Platinum efficiency directly translates to lower PUE (Power Usage Effectiveness) metrics, a critical KPI for green data center certifications. However, realizing its full potential requires integration with Cisco’s Crosswork Automation to dynamically power down underutilized racks. In an era where energy costs rival CapEx in TCO calculations, this PSU transforms power management from an operational chore to a strategic advantage.