littelfuse.com© 2015 Littelfuse Revised: 10/09/15
Specifications are subject to change without notice.
MDSR-7 12.7mm Sub-miniature Reed Switch
Description
The MDSR-7 Reed Switch is a sub-miniature, normally open switch with a
12.70mm long x 1.80mm diameter (0.500” x 0.071”) glass envelope, capable of
switching 200Vdc at 10W. It has high insulation resistance of 10¹² ohms
minimum and low contact resistance of less than 100 milli-ohms.
Agency Approvals
Agency Agency File Number Ampere-Turns Range
E47258
E471070 10-25 AT
DEMKO 14 ATEX 1393U 10-25 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
• Capable of switching 200V or 0.5A
at up to 10W
• Available sensitivity range
10-25 AT
Benefits
• Hermetically sealed switch
contacts are not affected by and
have no effect on their external
environment
• Low, stable contact resistance
• Zero operating power required
for contact
• Excellent for switching micro-
controller logic level loads
Applications
• Reed Relays (particularly suited
to ATE type applications)
• Security Systems
• Limit Switching
• Office Equipment
Dimensions
Dimensions in mm (inch)
Low Power > MDSR-7
RoHS
Note: SPST-NO = Single-pole, single-throw, normally open
Electrical Ratings
Contact Rating 1W/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.
0.5
0.35
0.80
Resistance Contact, Initial
Insulation
Ω - max.
Ω - min.
0.100
1012
Capacitance Contact pF - typ. 0.3
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.
CL OF OVERLAP
20.19
(.795) REF.
13.46
(.530) MIN.
12.70
(.500) MAX.
40.38
(1.590) NOM.
1.80
(.071) MAX.
0.47
(0.1
85) DIA. REF.
littelfuse.com© 2015 Littelfuse Revised: 10/09/15
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 5.5kHz - 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 > MDSR-7
MDSR-7 12.7mm Sub-miniature Reed Switch
MDSR-7-10-15
Series
AT Range
10-25 AT
10-15 AT
15-20 AT
20-25 AT
Example:
10-15 AT product is
MDSR-7-10-15
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.
5
0
10
15
20
25
50
Pull-In (AT, L4989 Coil)
Drop-Out (AT, L4989 Coil)
10 15 20 25 30
35
Max.
Min.
Magnetic Characteristics
Pull-In Range 3Ampere Turns 10-25
Rating Sensitivity 4Ampere Turns 20
Test Coil L4989
