What is the difference between Passive DAC and Active DAC Cables?

Pactech is proud to continue offering extensive support to our customers in Hi-speed cables for data center applications, by being the first total solution provider in all form factors covering SFP/QSFP/DSFP/SFPDD/QDD/OSFP. This includes supporting 25G-800G aggregated data-rate in both Passive and Active DAC solutions.

For Passive DAC solutions, we offer 50G-400G PAM4 passive with an extended reach of 3.0m for QDD/OSFP and 4.0m for SFP56/QSFP56/SFPDD/DSFP. 

For Active DAC, we have cable lengths of up to 10m in QSFP28 for 25G-100G, validated 8m for 50G-400G PAM4, and 10m in Q56/DSFP56/SFPDD.

Active DAC vs. Passive DAC

What’s the difference between Active DAC and Passive DAC cables? The main difference is that Active DAC contains electronics for signal conditioning, and Passive DAC does not contain electronics for signal conditioning.

Passive DAC cables are used when signal conditioning integrated into a port is provided by a switch. It costs less than Active DAC, but has a higher upfront cost.

Active DAC cables are used when signal conditioning integrated into a port is not provided by a switch. Active DAC generally costs more than Passive DAC, but the switch that comes with Active DAC costs less.

DAC Cable Features: Comparing Active vs Passive

800G OSFP 

Passive DAC Features

  • Proprietary high-performance twinax technology enables industry’s longest reach for passive DAC cables
    • Up to 4.0m for 50G PAM4 (1.0m longer than standard industry practice)
    • Increased flexibility using a co-extrusion technology
  • Superior signal integrity and electrical performance
    • IEEE 802.3cd compliant
    • Channel Operating Margin (COM) 1.0dB higher than standard guaranteed
    • BER<1E-5 with no FEC
    • 360-degree EMI shielding
    • Proprietary crosstalk noise mitigation technology
    • High-temperature performance stability (support stable low BER at 60+ Celsius)
    • 100% in-line production signal integrity test with data-tracking by S/N
  • Enhanced reliability for worry-free field deployment
    • 500H 85°C&85%RH aging testing – 850K+ Hour MTBF
    • 1000H 85°C&85%RH aging solution available for Telecom/1.7million+ hour MTBF
    • 200 mating cycles guaranteed
  • Many customization options available
    • Labeling
    • Pull-tab color
    • Cable color
    • EEPROM including multi-vendor native compatible EEPROM
QSFP56 to 2xQSFP56 Active Breakout

Active DAC Features

  • High-performance twinax technology
  • Analog re-driver based solutions
  • Industry’s most cost/performance competitive in
    • Power consumption: <0.1W/channel and <1.0W/400G
    • Latency: latency at picoseconds
    • Plug-n-play: use as direct attached cable
    • Extended reach: up to 10m
    • High-temperature performance stability: support stable low BER at 60+ Celsius
    • Low BER (< 1E-5 with no FEC)
    • In-line 100% SI testing for mass production with both BER & VNA
    • EEPROM coding: native Arista/Cisco Nexus/Juniper/MSA EERPOM available
    • Compliance to IEEE 802.3cd
  • Enhanced reliability as passive DAC
    • 500H 85°C&85%RH aging testing – 850K+ Hour MTBF
    • 200 mating cycles guaranteed

We are looking forward to sharing our DAC/ADAC product portfolio with you.

Contact us, visit the product page or read our product pdf to learn more. Thank you.