40G QSFP+ To 4x10G SFP+ DAC Cable

 

Signal Integrity

(ITEM)		(REQUIREMENT)					(TEST CONDITION)
(Differe ntial Impedan ce)	Cable Impedance	105+5/-5Ω					Rise time of 35ps (20 % - 80 %).
	Paddle Card Impedance	100±10Ω
	Cable Termination Impedance	100±15Ω
[Differential (Input/Output)Return loss SDD11/SDD22]		Return loss(f)≥ 10 0.01≤f﹤4.1 6.3-13log10(f/ 5.5) 4.1≤f≤11.1 Where f is the frequency in GHz Return loss(f) is the return loss at frequency f					0.01GHz≤f≤11.1GH z SFF-8431 Rev.4.1
[Differential Insertion Loss (SDD21 Max.)]		(Differential InsertionLoss Max. For TPa to TPb Excluding Test fixture )					10MHz≤f ≤5GHz
		F AWG	0.6GHz	1.25GHz	2.5GHz	5.0GHz
		30AWG(1m)Max.	2dB	3dB	4.5dB	7.5dB
		30 AWG(2m)Max.	4dB	5dB	7dB	10dB
		28AWG(3m)Max.	4dB	5.5dB	7.5 dB	12dB
		26AWG(5m)Max.	5.5dB	7dB	10dB	16.0dB
		24AWG(7m&10m )Max.	6.5dB	10dB	14dB	21dB
[MDNEXT(multiple disturber near-end crosstalk)]		≥26dB					10MHz≤f ≤5GHz
[Insertion Loss Deviation]		-0.7-0.2*10-3f ≤ ILD ≤ 0.7+0.2*10-3f (f is the frequency in MHz),					10MHz≤f ≤5GHz

 

Other Electrical Performance

 

(ITEM)	(REQUIREMENT)	(TEST CONDITON)
[Low Level Contact Resistance]	70milliohms Max. From initial.	EIA-364-23:Apply a maximum voltage of 20mV And a current of 100 mA.
Insulation Resistance	10Mohm(Min.)	EIA364-21:AC 300V 1minute
[Dielectric Withstanding Voltage]	DC 500V 1 minute disruptive discharge.	EIA-364-20:Apply a voltage of 500 VDC for 1minute between adjacent terminals And between adjacent terminals and ground.

 

Environment Performance

 

(ITEM)	(REQUIREMENT)	(TEST CONDITON)
[Operating Temp. Range]	-20°C to +75°C	Cable operating temperature range.
[Storage Temp. Range (in packed condition)]	-25°C to +65°C	Cable storage temperature range in packed condition.
[Thermal Cycling Non-Powered]	No evidence of physical damage	EIA-364-32D, Method A, -25 to 90C, 100 cycles, 15 min. dwells
[Salt Spraying]	48 hours salt spraying after shell corrosive area less than 5％.	EIA-364-26
Mixed Flowing Gas	Pass electrical tests per 3.1 after stressing. (For connector only)	EIA-364-35 Class II,14 days.
Temp. Life	No evidence of physical damage	EIA-364-17C w/ RH, Damp heat 90℃ at 85% RH for 500 hours then return to ambient
Cable Cold Bend	4H,No evidence of physical damage	Condition: -20℃±2℃, mandrel diameter is 6 times the cable diameter.

 

Mechanical and Physical Characteristics

(ITEM)	(REQUIREMENT)	(TEST CONDITON)
Vibration	Pass electrical tests per 3.1 after stressing.	Clamp & vibrate per EIA-364-28E, TC-VII, test condition letter – D, 15 minutes in X, Y & Z axis.
Cable Flex	No evidence of physical damage	Flex cable 180° for 20 cycles (±90° from nominal position) at 12 cycles per minute with a 1.0kg load applied to the cable jacket. Flex in the boot area 90º in each direction from vertical. Per EIA-364-41C
Cable Plug Retention in Cage	90N Min. No evidence of physical damage	Force to be applied axially with no damage to cage. Per SFF 8661 Rev 2.1 Pull on cable jacket approximately 1 ft behind cable plug. No functional damage to cable plug below 90N. Per SFF-8432 Rev 5.0
Cable Retention in Plug	90N Min. No evidence of physical damage	Cable plug is fixtured with the bulk cable hanging vertically. A 90N axial load is applied (gradually) to the cable jacket and held for 1 minute. Per EIA-364-38B
Mechanical Shock	Pass electrical tests Per 3.1 after stressing.	Clamp and shock per EIA-364-27B, TC-G,3 times in 6 directions, 100g, 6ms.
Cable Plug Insertion	40N Max.(QSFP+) 18N Max.(SFP+)	Per SFF8432 Rev 5.0.
Cable plug Extraction	30N Max. (QSFP28) 12.5N Max. (SFP28)	Measure without the aid of any cage kick-out springs. Place axial load on de-latch to de-latch plug. Per SFF-8432 Rev 5.0.
Durability	50 cycles,No evidence of physical damage	EIA-364-09, perform plug &unplug cycles:Plug and receptacle mate rate: 250times/hour. 50times for QSFP28/SFP28 module (CONNECTOR TO PCB)

 

 

High-speed data centers and networking environments demand reliable, cost-effective connectivity solutions. DAC Cable technology has emerged as the preferred choice for short-distance, high-bandwidth applications, offering superior performance without the complexity and cost of active optical solutions.

What Makes DAC Cable the Smart Choice for Data Centers

DAC Cable assemblies provide direct electrical connections between network equipment, eliminating the need for optical transceivers in short-reach applications. This passive copper technology delivers exceptional signal integrity while significantly reducing power consumption and infrastructure costs.

The architecture of a DAC Cable consists of twinaxial copper conductors with integrated connectors-typically SFP+, QSFP+, or QSFP28 form factors. Unlike fiber optic alternatives, these cables require no additional power for signal conversion, making them ideal for top-of-rack switching and server-to-switch connections within the same cabinet or adjacent racks.

Performance Advantages of Modern DAC Cable Technology

Today's DAC Cable solutions support data rates from 10G to 100G and beyond, meeting the demands of bandwidth-intensive applications. The carefully engineered impedance characteristics ensure minimal signal degradation across the transmission path, while advanced shielding techniques prevent electromagnetic interference.

Temperature resilience represents another crucial advantage. Quality DAC Cable assemblies maintain consistent performance across operating temperature ranges from -20°C to +75°C, ensuring reliability in diverse data center environments. This thermal stability, combined with robust mechanical design, delivers years of maintenance-free operation.

Key Considerations When Selecting DAC Cable Solutions

Cable Length and Signal Integrity

The relationship between cable length and signal quality remains fundamental to DAC Cable performance. Shorter cables-typically 1-3 meters-provide the best insertion loss characteristics and highest signal fidelity. As distance increases, careful attention to wire gauge becomes critical. Thicker conductors (lower AWG numbers) maintain better signal integrity over longer runs, with 24AWG cables supporting distances up to 10 meters while meeting stringent performance requirements.

Connector Compatibility

Modern DAC Cable assemblies must integrate seamlessly with your existing infrastructure. QSFP28 connectors support 100G applications with controlled insertion and extraction forces, while SFP28 variants serve 25G requirements. The mechanical design ensures secure retention in cages and hosts, with pull forces exceeding 90N to prevent accidental disconnection during routine maintenance.

Environmental Durability

Data center environments expose DAC Cable assemblies to vibration, thermal cycling, and physical stress. High-quality cables withstand thousands of flexing cycles, extensive vibration testing, and mechanical shock without performance degradation. Salt spray resistance and mixed flowing gas exposure testing validate long-term reliability in challenging conditions.

DAC Cable vs. Active Optical Cables: Making the Right Choice

While both technologies serve high-speed networking needs, DAC Cable solutions offer distinct advantages for specific use cases. The passive design eliminates power consumption entirely-a significant benefit when aggregated across hundreds of connections. Lower cost per port and reduced failure points make DAC Cable the economical choice for short-reach applications.

However, distance limitations must be acknowledged. Beyond 10 meters, optical solutions become necessary. The decision point typically falls around 7 meters, where DAC Cable cost advantages begin diminishing relative to fiber alternatives.

Installation Best Practices for DAC Cable Deployments

Proper handling preserves DAC Cable performance throughout its lifecycle. Maintain minimum bend radius requirements-generally 6 times the cable diameter-to prevent conductor damage and impedance variations. When routing cables through dense rack environments, avoid tight pinch points and ensure adequate slack for future maintenance access.

Cable management becomes particularly important in high-density deployments. Organize DAC Cable runs to minimize crosstalk between adjacent pairs, and maintain separation from high-power cables that could introduce electromagnetic interference. Proper strain relief at connector terminations prevents mechanical stress from transferring to delicate contact points.

Future-Proofing Your Infrastructure with DAC Cable Technology

As data rates continue escalating, DAC Cable technology evolves to meet new challenges. Advanced manufacturing techniques improve signal integrity margins, while enhanced shielding designs address crosstalk concerns in 400G applications. Investing in quality DAC Cable solutions today positions your infrastructure for tomorrow's bandwidth demands.

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Frequently Asked Questions About DAC Cable

Q: What's the maximum effective distance for DAC Cable connections?

A: DAC Cable assemblies typically perform optimally up to 7-10 meters, depending on data rate and cable gauge. For 10G and 25G applications, 7-meter runs using 24AWG conductors deliver excellent performance. Higher data rates or longer distances may require thicker conductors or alternative technologies.

Q: Can DAC Cable replace fiber optic connections in my data center?

A: DAC Cable serves as an ideal fiber replacement for short-reach connections-particularly top-of-rack switching and intra-cabinet links. The passive design eliminates transceiver costs and power consumption. However, for runs exceeding 10 meters or applications requiring electrical isolation, fiber optic solutions remain necessary.

Q: How does temperature affect DAC Cable performance?

A: Quality DAC Cable assemblies maintain consistent electrical characteristics across operating temperatures from -20°C to +75°C. The conductor materials and dielectric insulators are engineered to minimize impedance variations with temperature, ensuring reliable signal transmission regardless of data center environmental conditions.

Q: What maintenance do DAC Cable assemblies require?

A: DAC Cable solutions are essentially maintenance-free. Regular visual inspections for physical damage and periodic cleaning of connector faces represent the only routine requirements. The passive design eliminates firmware updates, power supply concerns, and other maintenance tasks associated with active components.

Q: How many insertion cycles can a DAC Cable withstand?

A: Professional-grade DAC Cable assemblies support minimum 50 insertion/extraction cycles without performance degradation. The spring-loaded contact design and robust mechanical construction ensure consistent electrical contact throughout the product lifecycle. Many installations far exceed this minimum in production environments.

Q: Do I need different DAC Cable types for different data rates?

A: DAC Cable assemblies are often backward compatible-a 100G QSFP28 cable typically supports 40G operation. However, optimal performance requires matching cable specifications to your target data rate. The conductor gauge, shielding design, and impedance characteristics are optimized for specific applications, so selecting the appropriate DAC Cable variant ensures best results.

Q: What's the difference between 28AWG and 24AWG DAC Cable?

A: Wire gauge directly impacts DAC Cable performance and flexibility. 28AWG cables offer superior flexibility and smaller bend radius, making them ideal for dense installations up to 3 meters. 24AWG cables use thicker conductors that reduce insertion loss, supporting longer runs up to 10 meters while maintaining signal integrity margins.

Q: Can DAC Cable support 400G data rates?

A: Modern DAC Cable technology continues advancing to support emerging standards. 400G-capable assemblies using QSFP-DD and OSFP form factors are now available for short-reach applications. These advanced cables incorporate enhanced shielding and tighter impedance control to meet the demanding signal integrity requirements of 400G transmission.

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