Amphenol® LJT and JT Series subminiature cylindrical
connectors are qualified to MIL-DTL-38999*, Series I
and II respectively. These connectors were developed
to meet the needs of the aerospace industry, and
provided the impetus for development of the
MIL-C-38999 specifications, which has been
superseded by MIL-DTL-38999. Meeting or exceeding
MIL-DTL-38999 requirements, Amphenol® JT/LJT
MIL-DTL-38999, Series II JT
MIL-DTL-38999, Series I LJT
Shell components are impact extruded or machined bar stock
aluminum. Standard plating on shell components
is cadmium over nickel. Many finishes are optional
Hermetic seal receptacles are available in carbon steel or stainless
steel shells. Dependable 5 key/keyway polarization with bayonet lock
coupling is incorporated to aid and assure positive mating.
Insert material is a rigid dielectric with excellent electrical characteristics,
providing durable protection for molded-in solder type contacts.
Contrasting letter or number designations are used on insert faces.
A fluorinated silicone interfacial seal wafer is featured
on the mating face of “crimp type pin” inserts. This assures complete electrical
isolation of pins when connector halves are mated. In addition, a main
joint gasket is installed in the receptacle for moisture sealing between
connector halves. Both features are also available for hermetic
Maximum design flexibility is built into the JT/LJT Series, with a minimum
of 2 to a maximum of 128 circuits per connector in a wide variety
of contact arrangements. Contacts are available in sizes 8, 10, 12, 16,
20, 22, 22D and 22M with standard 50 micro inch minimum gold plating
(100 micro inches optional). All socket contacts are probe proof. Crimp
type rear removable contacts are featured in JT-R and LJT-R
connectors. Solder termination contacts are also available, as well as
PCB, wire wrap, thermocouple, fiber optic, coaxial, triaxial and twinax
Optional Features High temperature capability of 392°F is available only
in JTS or LJTS crimp type connectors. High temperature versions feature
gold plated contacts, high temperature shell plating, stainless steel coupling
nut spring, and epoxy inserts/fluorinated silicone grommet combination.
Standard temperature capability for both solder and crimp is 302°F.
The JTN or LJTN type connectors are available for N2O4resistance
provided they are mated, and un-grommeted rear faces are
Features & Benefits
• Lightweight, Space Saving Design
• Contact Protection - 100% scoop-proof LJT design prevents
bent pins and short circuits during mating
• Quick Positive Coupling - 3 point bayonet lock system
• Mismating Eliminated - with 5 key/keyway design
• Error Proof Alternate Positioning - insured by different key/
• EMI Shielding - grounding fingers standard in LJT Series;
optional in JT Series
• Nine Shell Sizes and a Variety of Shell Styles
• Contact Options - size 8, 10, 12, 16, 20, 22M and 22D Crimp,
Solder, PCB, Wire wrap, Coax, Twinax, Triax, Thermocouple,
Fiber Optic and Filter
• Fixed Solder Contacts - Amphenol MIL-DTL-38999 Series I
LJT and II JT, are available in solder versions as both
Commercial and Military qualified to MIL-DTL-27599
• Hermetic - air leakage limited to 1 X 10-7 cm3 per second
• “Breakaway” Lanyard Release Style - available in LJT plugs.
Provides quick disconnect of the connector plug and receptacle
with axial pull on the lanyard. See pages 94-96.
• Inventory Support Commonality - uses standard
MIL-DTL-38999 contacts, insert arrangements and
• RoHS Compliant Product Available -
Consult Amphenol Aerospace Operations.
Where proof of high reliability and lot control is required, MS approved
equivalents to most proprietary
JT and LJT connectors are available.
* MIL-DTL-38999 Series I supersedes MIL-C-38999 Series I.
MIL-DTL-38999 Series II supersedes MIL-C-38999 Series II.
MIL-DTL-38999 Series I LJT