Circular Connectors

Part Number	Description / PDF	Quantity
MD-90SN CUI Devices	CONN RCPT FMALE MINI DIN 9P SLDR	160
MD-40SV CUI Devices	CONN RCPT FMALE MINI DIN 4P SLDR	1488
MD-30 CUI Devices	CONN PLUG MALE MINI DIN 3P SLDR	8913
MD-60SG CUI Devices	CONN RCPT FMALE MINI DIN 6P SLDR	0
PD-40 CUI Devices	CONN JACK FMALE 4POS TIN SOLDER	4599
SD-70SN CUI Devices	CONN RCPT FMALE DIN 7P SOLDER	1319
SDS-70J CUI Devices	CONN RCPT FMALE DIN 7POS SOLDER	1396
MD-90SM CUI Devices	CONN RCPT FMALE MINI DIN 9P SLDR	1400
MD-50SP CUI Devices	CONN RCPT FMALE MINI DIN 5P SLDR	323
SD-70 CUI Devices	CONN PLUG MALE DIN 7P SOLDER CUP	970
MD-40SGK CUI Devices	CONN RCPT FMALE MINI DIN 4P SLDR	4715
SD-30LS CUI Devices	CONN RCPT FMALE DIN 3P SOLDER	1396
SDS-40J CUI Devices	CONN RCPT FMALE DIN 4POS SOLDER	766
MD-30SV CUI Devices	CONN RCPT FMALE MINI DIN 3P SLDR	647
MD-70SN CUI Devices	CONN RCPT FMALE MINI DIN 7P SLDR	0
SD-40LP CUI Devices	CONN PLUG MALE DIN 4P SOLDER	916
SD-40 CUI Devices	CONN PLUG MALE DIN 4P SOLDER CUP	1580
SDF-130J CUI Devices	CONN RCPT FMALE DIN 13P SOLDER	2173
MD-40SG CUI Devices	CONN RCPT FMALE MINI DIN 4P SLDR	150
SDD-130J CUI Devices	CONN RCPT FMALE DIN 13P SOLDER	205

Circular Connectors

1. Overview

Circular connectors are multi-pin electrical connectors with circular contact arrangements, designed for reliable signal/power transmission in harsh environments. They feature robust mechanical structures, environmental sealing, and high mating durability. These connectors are critical in aerospace, industrial automation, and medical equipment where vibration resistance and signal integrity are paramount.

2. Main Types & Functional Classification

Type	Functional Characteristics	Application Examples
MIL-DTL-38999	High-density, threaded coupling, EMI shielding	Aerospace systems, military vehicles
USB Type-C	Reversible design, 10Gbps data rate, 100W power delivery	Smartphones, laptops, PDAs
BNC	Bayonet locking, 2GHz frequency range	Test equipment, video systems
LVDT Circular	Linear variable differential transformer integration	Industrial sensors, robotics

3. Structure & Components

Typical construction includes: - Shell: Aluminum alloy/zinc die-cast housing with corrosion-resistant plating - Contacts: Gold-plated phosphor bronze with 0.5-2.0mm diameter - Insulation: High-temperature thermoplastic (200 C rating) - Sealing: IP67/IP68 rated elastomer gaskets - Mounting: Threaded/flange/clamp mechanisms

4. Key Technical Parameters

Parameter	Typical Range	Importance
Voltage Rating	50V-600V	Determines power transmission capacity
Current Rating	1A-25A/contact	Affects thermal performance
Contact Resistance	5m	Impacts signal integrity
IP Rating	IP40-IP68	Defines environmental protection level
Operating Temp	-65 C to +200 C	Material stability indicator
Mating Cycles	500-10,000	Service life predictor

5. Application Fields

Aerospace: Flight control systems, satellite antennas
Industrial: CNC machines, automated guided vehicles
Medical: MRI scanners, patient monitoring systems
Telecom: 5G base stations, fiber optic networks
Consumer: VR headsets, gaming peripherals

6. Leading Manufacturers

Manufacturer	Key Products	Special Features
Amphenol	MIL-DTL-38999 series	Composite materials, EMI filtering
TE Connectivity	DEUTSCH D38999	Thermoplastic housing, 2000V dielectric
Molex	USB Type-C 10Gbps	Shielded twinax design
Delphi	Automotive circular connectors	IP69K rating for EV charging
Lemo	Push-pull circular series	Subminiature, 5000+ mating cycles

7. Selection Guidelines

Key considerations: 1. Environmental factors: Temperature extremes, fluid exposure 2. Electrical requirements: Signal type (analog/digital), current load 3. Mechanical constraints: Panel space, mating force limitations 4. Compliance standards: MIL-STD, ISO 6722, RoHS 5. Cost vs. longevity: High-cycle applications justify premium connectors

8. Industry Trends

Emerging developments include: - Miniaturization: 1.0mm contact pitch enabling wearable devices - High-speed transmission: 25Gbps+ differential pairs for industrial IoT - Smart connectors: Integrated sensors for condition monitoring - Material innovation: Graphene-coated contacts reducing resistance - Eco-design: Halogen-free thermoplastics meeting REACH regulations