littelfuse.com© 2020 Littelfuse Revised: BO.11/25/20
Specifications are subject to change without notice.
MDCG-4 15.3mm Sub-miniature Reed Switch
Description
The MDCG-4 Reed Switch is a sub-miniature, normally open switch with a
15.24mm long x 2.28mm diameter (0.600” x 0.090”) glass envelope, capable of
switching 200Vdc at 10W. It has high insulation resistance of 1010 ohms
minimum and contact resistance less than 100 milli-ohms. This reed switch is
also available in a surface mount version, that is, MDSM-4.
Agency Approvals
Agency Agency File Number Ampere-Turns Range
E47258
E471070 12-38 AT
Switch Type
Contact Form A (SPST-NO)
Materials Body: Glass
Leads: Tin-plated Ni-Fe wire
Axial Lead Reed Switches
Features
• Sub-miniature normally
open switch
• Available sensitivity 12-38 AT
• Capable of switching 200Vdc or
0.5A at up to 10W
Benefits
• Hermetically sealed switch
contacts are not affected by and
have no effect on their external
environment
• Zero operating power required for
contact closure
• Excellent for switching micro-
controller logic level loads
Applications
• Reed Relays
• Security
• Limit Switching
• Level Sensing
• Office Equipment
• Industrial Control
Dimensions
Dimensions in mm (inch)
Low Power > MDCG-4
RoHS
Note: SPST-NO = Single-pole, single-throw, normally open
Electrical Ratings
Contact Rating 1
W/VA - max. 10
Voltage 3
Switching 2
Breakdown 4
Vdc - max.
Vac - max.
Vdc - min.
200
140
250
Current 3
Switching 2
Carry
Adc - max.
Aac - max.
Adc - max.
0.50
0.35
1.20
Resistance Contact, Initial
Insulation
Ω - max.
Ω - min.
0.100
1010
Capacitance Contact pF - typ. 0.2
Temperature Operating
Storage 5
°C
°C
-40 to +125
-65 to +125
Notes:
1. Contact rating - Product of the switching voltage and current should never exceed the wattage rating. Contact Littelfuse for additional load/life information.
2. When switching inductive and/or capacitive loads, the effects of transient voltages and/or currents should be considered. Refer to Application Notes AN108A and AN107 for details.
3. Electrical Load Life Expectancy - Contact Littelfuse with voltage, current values along with type of load.
4. Breakdown Voltage - per MIL-STD-202, Method 301.
5. Storage Temperature - Long time exposure at elevated temperature may degrade solderability of the leads.
20.19
(.795) REF.
12.19
(.480) MIN.
15.24
(.600) MAX.
40.38
(1.590) NOM.
2.28
(.090) DIA. MAX.
0.50
(.020) DIA. REF.
CL OF OVERLAP
Note: Contact Littelfuse for specific agency approval ratings.
littelfuse.com© 2020 Littelfuse Revised: BO.11/25/20
Specifications are subject to change without notice.
Drop-Out vs. Pull-In Chart
Packaging
Packaging Option Packaging Specification Quantity Quantity & Packaging Code Taping Width
Bulk Bulk 1000 N/A N/A
Product Characteristics
Operating Characteristics
Operate Time 10.6ms - max.
Release Time 10.2ms - max.
Shock 211ms 1∕2 sine wave 100G - max.
Vibration 250-2000 Hertz 30G - max.
Resonant Frequency 3.9kHz - typ.
Part Numbering System
Notes:
1. Operate (including bounce)/Release Time - per EIA/NARM RS-421-A,diode suppressed coil (Coil II).
2. Shock and Vibration - per EIA/NARM RS-421-A and MIL-STD-202.
3. Pull-In Range - Contact Littelfuse for narrower AT ranges available.
4. Rating Sensitivity - The value at which contact ratings and operating characteristics are determined. Derating may be required below this value.
5. Custom modifications of forming and/or cutting of reed switches are available. Please contact Littelfuse.
Axial Lead Reed Switches
Low Power > MDCG-4
MDCG-4 15.24mm Sub-miniature Reed Switch
MDCG-4 -12-18
Series
AT Range
12-18 AT
12-23 AT
17-23 AT
17-28 AT
22-28 AT
22-33 AT
27-33 AT
27-38 AT
32-38 AT
Example:
12-18 AT product is
MDCG-4-12-18
Note: Chart represents the range of Drop-Out, min to max for a given Pull-In value. Note: These AT values are the before-modification values of the bare reed switch.
Magnetic Characteristics
Pull-In Range 3Ampere Turns 12-38
Rating Sensitivity 4Ampere Turns 20
Test Coil L4989
5
0
10
15
20
25
30
Drop-Out (AT, L4989 Coil)
50
Pull-In (AT, L4989 Coil)
10 15 20 25 30 35
40
Max.
Min.
