SMK - 50 Ohm Connectors (2.92mm)
INCHES (MILLIMETERS)
•
CUSTOMER DRAWINGS AVAILABLE UPON REQUEST
Johnson Components
™
SMK (2.92mm) Connectors
The Johnson Components
™
SMK
Connector provides an excellent solution
for demanding applications requiring high
frequency transmission. Although similar to the
SMA interface, a smaller internal body diameter
(2.92mm) and air dielectric provide a higher
cutoff frequency and other key advantages:
• Precision manufacturing allows superior
electrical performance to 40 GHz.
• Female contacts have a unique three-slot
construction, which enhances connectivity by
creating a more rugged connector while reducing the chance of intermittent connections.
• Precise assembly tooling assures excellent, repeatable contact and support bead location
on cabled connectors.
• Connector mating interface per MIL-STD-348
• Mating interface control provides consistent electrical performance.
• The plug connector VSWR is 1.20 Max to 40 GHz and a 12 inch SMK plug to plug cable assembly
performs better than 1.35 VSWR to 40 GHz.
• The Field Replaceable Jacks are teamed with a high quality hermetic seal feed thru for use in sealed
circuit modules.
• The SMK plug interface employs more precise dimensions than an SMA and uses a shorter snub nose
male pin such that the connector bodies align before the contacts engage.
MATERIAL SPECIFICATIONS
Bodies:
Stainless steel per QQ-B-626, gold plated* per MIL-G-45204
.00005" min. or passivated per MIL-F-14072 B (EL) 300
Contacts:
Female - beryllium copper per QQ-C-530, gold plated per MIL-G-45204
.00005" min.
Contact Support Beads:
PTFE fluorocarbon per ASTM D 1710 and
ASTM D 1457 or modified PPE resin
Seal Rings:
Silicone rubber per ZZ-R-765
* All gold plated par ts include a .00005" min. nickel underplate barrier layer.
Mating Engagement for SMK (2.92mm) Series per MIL-STD-348
MECHANICAL RATINGS
Engagement Design:
MIL-STD-348, Series SMK (2.92mm)
Engagement/Disengagement Force:
2 inch-pounds maximum
Mating Torque:
7 to 10 inch-pounds
Coupling Proof Torque:
15 inch-pounds minimum
Coupling Nut Retention:
60 pounds minimum
Contact Retention:
6 lbs. minimum axial force (captivated contacts)
Axial Force*(lbs) Torque (in-oz)
Cable Retention:
.086 semi-rigid ..................................... 30
16
.141 semi-rigid ..................................... 60
55
*Or cable breaking strength whichever is less.
Durability:
500 cycles minimum
Notes:
1. ID of contact shall meet VSWR and connectivity requirements when
mated with dia. .0355-.0365 male pin.
2
Johnson Components
™
• P.O. Box 1732 • Waseca, MN 56093-0832 • 1-800-247-8256 • Fax: 507-833-6287 • www.johnsoncomponents.com
SMK - 50 Ohm Connectors (2.92mm)
INCHES (MILLIMETERS)
•
CUSTOMER DRAWINGS AVAILABLE UPON REQUEST
ELECTRICAL RATINGS
Impedance:
50 ohms
Frequency Range:
0-40 GHz
VSWR:
(f = GHz)
Semi-rigid straight cabled connectors and adapters .............. 1.20 Max
Field replaceable (see
typical return loss graph) ............................
N/A
Working Voltage:
(Vrms maximum)
Connectors for Cable Type
Sea Level 70K Feet
.086 semi-rigid and field replaceable......................... 335
85
.141 semi-rigid and adapters ..................................... 500
125
Dielectric Withstanding Voltage:
(VRMS minimum at sea level)
.086 semi-rigid and field replaceable............................................. 1000
.141 semi-rigid and adapters ......................................................... 1500
Corona Level:
(Volts minimum at 70,000 feet)
.086 semi-rigid and field replaceable............................................... 250
.141 semi-rigid and adapters ........................................................... 375
Insertion Loss:
(dB maximum)
Adapters ................................................ 0.06 f (GHz), tested at 6 GHz
Straight semi-rigid cable connectors ....... 0.03 f (GHz), tested at 10 GHz
Insulation Resistance:
5000 megohms minimum
Contact Resistance:
(milliohms maximum)
Initial After Environmental
Center contact straight cabled connectors ... 3.0*
4.0
Center contact adapters ................................ 4.0
6.0
Field replaceable connectors ........................ 6.0
8.0
Outer contact (all connectors) ....................... 2.0
N/A
Body to cable (gold plated connectors) ......... 0.5
N/A
Body to cable (passivated connectors) ......... 5.0
N/A
RF Leakage:
(dB minimum, tested at 2.5 GHz) ............................. -90dB
RF High Potential Withstanding Voltage:
(Vrms minimum, tested at 4
and 7 MHz)
=
.086 semi-rigid and field replaceable.............................................. 670
.141 semi-rigid and adapters ........................................................ 1000
ENVIRONMENTAL RATINGS
(Meets or exceed the applicable paragraph of MIL-C-39012)
Temperature Range:
- 65°C to + 165°C
Thermal Shock:
MIL-STD-202, Method 107, Condition B
Corrosion:
MIL-STD-202, Method 101, Condition B
Shock:
MIL-STD-202, Method 213, Condition I
Vibration:
MIL-STD-202, Method 204, Condition D
Moisture Resistance:
MIL-STD-202, Method 106
FIELD REPLACEABLE APPLICATION NOTES
The field replaceable connectors manufactured by Johnson Components
™
,
are easy to install and replace. The hermetic seal is mounted into the circuit
module wall and the connector can be removed and replaced without de-
stroying the hermeticity of the circuit housing.
The field replaceable connector creates a transition from microstrip circuitry
to a coaxial transmission line. The SMK (2.92mm) seal pin diameter is .012
(.030) to minimize the capacitive effects on the circuit trace. For optimum
electrical performance, the transition from the hermetic seal to the microstrip
trace must be properly compensated. Compensation involves adjusting
the microstrip trace width to minimize any impedance discontinuities found
in the transition area.
The plot shown below is representative of the typical return loss of a Johnson
Components
™
field replaceable SMK connector. To produce the data shown
below, a test fixture is created using the Johnson Components
™
SMK her-
metic seal. The fixture consists of a suitably thick spacer plate with the
hermetic seal mounted flush to both surfaces. Two connectors are mounted
back to back around the fixture and the VSWR of this test assembly is
measured. The calculated return loss trace shown is equivalent to the square
root of the measured VSWR of the test assembly. Since the connectors
tested are of identical design, it can be stated with fair accuracy that the
calculated data shown represents the response of a single field replaceable
connector and its transition to the hermetic seal.
Although Johnson Components
™
does not publish a VSWR specification
for field replaceable connectors, typical connector return loss can be ex-
pected to be less than -20 dB through 40 GHz. A VSWR specification is not
stated because an industry standard method for testing field replaceable
connectors does not exist. The actual performance of the connector is
dependent upon the following:
1. For optimum electrical performance, Johnson Components
™
recommends
the use of our standard 142-1000-033 hermetic seal with a pin diameter
of .0120 (0.305) +/- .0005 (0.013).
2. It is recommended that the hermetic seal be mounted flush with the cir-
cuit housing. Tolerance variations between the hermetic seal and ma-
chined housing do not always guarantee an optimum transition to the
connector. Some manufacturers recommend an additional counterbore
in the circuit housing to accommodate a solder washer during installation
of the seal. Johnson Components
™
does not recommend this type of
installation because if the counterbore is not completely filled with solder,
electrical discontinuities may be created.
3. The transition between the hermetic seal pin and the microstrip trace will
effect electrical performance, as stated above. Several different meth-
ods of hermetic seal mounting and seal pin to microstrip trace attach-
ment are used in the industry.
FIELD REPLACEABLE TEST ASSEMBLY
3
SMK - 50 Ohm Connectors (2.92mm)
INCHES (MILLIMETERS)
•
CUSTOMER DRAWINGS AVAILABLE UPON REQUEST
Straight Solder Type Plug - with contact, slide-on nut
CABLE TYPE
.086 Semi-Rigid
.141 Semi-Rigid
GOLD PLATED
145-0693-001
145-0694-001
PASSIVATED*
145-0693-002
145-0694-002
Assembly instructions on back page.
* Passivated coupling nut, gold plated body.
2-Hole Flange Mount Jack Receptacle
Mounting Hole Layout
ACCEPTS PIN SIZE
.0120 +/- .0005 (0.305 +/- .013)
GOLD PLATED
145-0701-601
PASSIVATED
145-0701-602
4-Hole Flange Mount Jack Receptacle
Mounting Hole Layout
ACCEPTS PIN SIZE
.0120 +/- .0005 (0.305 +/- .013)
GOLD PLATED
145-0701-611
PASSIVATED
145-0701-612
4
Johnson Components
™
• P.O. Box 1732 • Waseca, MN 56093-0832 • 1-800-247-8256 • Fax: 507-833-6287 • www.johnsoncomponents.com
SMK - 50 Ohm Connectors (2.92mm)
INCHES (MILLIMETERS)
•
CUSTOMER DRAWINGS AVAILABLE UPON REQUEST
Jack Receptacle - Thread Mount Field Replaceable
ACCEPTS PIN SIZE
.0120 +/- .0005 (0.305 +/- .013)
GOLD PLATED
145-0701-001
PASSIVATED
145-0701-002
Mounting Hole Layout
Hermetic Seal Feedthru
PART
ITEM 1
NUMBER
OUTER RING
142-1000-033 Kovar
Gold pl .00005 min. over
Nickel pl .00005 min.
ITEM 2
INSULATOR
Glass
Corning 7070
or equivalent
ITEM 3
PIN
Kovar
Gold pl .00005 min. over
Nickel pl .00005 min.
Notes:
1. The hermetic seal should be mounted as flush as possible with the hous-
ing. Excessive recession will create a high impedance air gap between
connection and housing which degrades electrical performance.
2. The use of an additional counterbore to accommodate a solder ring for
seal mounting is not recommended. A slight chamfer may be used if care
is taken to completely fill the area with solder -
avoid air gaps.
Electrical:
Impedance: 50 Ohms
Frequency Range: DC to 40 GHz
VSWR: Dependent upon application
Working Voltage: 250 Vrms max at sea level
Dielectric Withstanding Voltage: 500 Vrms min. at sea
level
Insulation Resistance: 5000 Megohm min.
Insertion Loss: 0.2 dB max at 40 GHz
Environmental:
Hermeticity: 1x10
-8
cc/sec at one atmosphere
Solderability: MIL-STD-202, Method 209
Operating Temperature: -55
O
C to 165
O
C
Jack to Jack In-Series Adapter
GOLD PLATED
145-0901-801
5
SMK - 50 Ohm Connectors (2.92mm)
INCHES (MILLIMETERS)
•
CUSTOMER DRAWINGS AVAILABLE UPON REQUEST
Plug to Plug In-Series Adapter
GOLD PLATED
145-0901-811
Plug to Jack In-Series Adapter
GOLD PLATED
145-0901-821
SMK (2.92mm) Tools
Accurate assembly of the SMK Cabled Connectors is obtained with the tools listed below.
Industry standard devices are used if possible for customer convenience and tool
compatibility.
A.
B.
E.
D.
C.
F.
ITEM
A
B
C
D
E
F
PART NUMBER
140-0000-962
140-0000-964
140-0000-965
140-0000-960
140-0000-961
140-0000-958
140-0000-959
140-0000-957
140-0000-968
DESCRIPTION
Semi-rigid Cable Vise (does not include inserts (B) or Vise Stop (F))
Cable Clamp Inserts, .086 Semi-rigid
Cable Clamp Inserts,.141 Semi-rigid
Contact Soldering Tool, .086 Plug
Contact Soldering Tool, .141 Plug
Body Soldering Tool, .086 Plug
Body Soldering Tool, .141 Plug
Bead Assembly Tool, Semi-rigid Plugs, All Cables
Vise Stop, (2.92mm)
6
Johnson Components
™
• P.O. Box 1732 • Waseca, MN 56093-0832 • 1-800-247-8256 • Fax: 507-833-6287 • www.johnsoncomponents.com