Series 120
Single Pole 4mm 2 ™ Reed Relays
Stacking on 4 mm x 4 mm pitch allowing the highest
packing density currently available
3, 5 or 12 V coils
Switching up to 1 A, 20 W
1 Form A (SPST) normally open (NO) energize to make
Plastic package with internal mu-metal magnetic screen
Sputtered ruthenium instrumentation grade switch
Insulation resistance >1012 Ω
Additional build options are available
Many benefits compared to industry standard relays (see last page)
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Package Type
The Series 120 reed relay range takes up the minimum board area making them ideal for very high density applications
such as A.T.E. switching matrices or multiplexers. Requiring a board area of only 4 mm x 4 mm, these relays allow the
highest packing density currently available.
Two switch types are available, a general purpose sputtered ruthenium switch rated at 15 Watts, 1 Amp (3 volt version) or
20 Watts, 1 Amp (5 & 12 volt versions) and a low level sputtered ruthenium switch rated at 10 Watts, 0.5 Amps.
The small size of the package does not allow an internal diode. Back EMF suppression diodes are included in many relay
drivers but if they are not, and depending on your drive methods, these may have to be provided externally.
While socketing relays is not normally recommended due to the risk of affecting contact resistance integrity, it is
appreciated that sockets may sometimes be desired for ease of servicing/replacement, in the case of a relay being damaged
or reaching the end of its working life. The device has pins on a 2 mm square pitch. There are suitable connectors available
from some manufacturers, both SMD and Through Hole, that will allow these relays to be stacked in either a row or in a
matrix on a 4 mm pitch.
Examples of Packing Density
Industry standard
reed relay of the
same electrical
specification
The above actual size graphic shows sixteen
Series 120 Relays packed into an area of 1.6 cm x 1.6 cm.
In comparison, only four of the industry standard reed
relays can be fitted into the same area.
A total of 528 Series 120 relays on a Pickering
Interfaces ultra-high-density PXI module
illustrates the packing density of these extremely
small Reed Relays.
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ISSUE 1.2 JAN 2022
Pickering
Electronics'
Series 120
Specification
Single Pole 4mm 2 ™ Reed Relays – Series 120
Switch Ratings - Dry Switches
1 Form A (energize to make)
20 W at 200 V
15 W at 200 V
10 W at 200 V
Series 120 switch ratings - contact ratings for each switch type
Switch
No
Switch
Power rating
form
Max.
switch
current
Max.
carry
current
Max.
switching
volts
Life
expectancy
ops typical
(see Note1)
Operate
time inc
bounce
(max)
Release
time
Special
features
1
A
20 W (*15 W)
1.0 A
1.2 A
200
109
0.5 ms
0.2 ms
General purpose
2
A
10 W
0.5 A
1.2 A
200
109
0.5 ms
0.2 ms
Low level
Switch no.2 is particularly good for switching low currents and/or voltages. It is the ideal switch for A.T.E. systems where
cold switching techniques are often used. Where higher power levels are involved, switch no.1 is more suitable.
Note1: Life Expectancy
The life of a reed relay depends upon the switch load and end of life criteria. For example, for an ‘end of life’ contact
resistance specification of 1 Ω, switching low loads (10 V at 10 mA resistive) or when ‘cold’ switching, typical life is approx
1 x 109 ops. At the maximum load (resistive), typical life is 1 x 107 ops. In the event of abusive conditions, e.g. high currents
due to capacitive inrushes, this figure reduces considerably. Pickering will be pleased to perform life testing with any
particular load condition.
Operating Voltages
Coil voltage - nominal
Must operate voltage - maximum at 25°C
Must release voltage - minimum at 25°C
3V
2.25 V
0.3 V
5V
3.75 V
0.5 V
12 V
9.0 V
1.2 V
Environmental Specification/Mechanical Characteristics
In the table below, the upper temperature limit can be extended to +125 °C if the coil drive voltage is increased to
accommodate the resistance/temperature coefficient of the copper coil winding. This is approximately 0.4% per °C. This
means that at 125 °C the coil drive voltage will need to be increased by approximately 40 x 0.4 =16% to maintain the
required magnetic drive level. Please contact sales@pickeringrelay.com for assistance.
Operating Temperature Range
-20 ºC to +85 ºC
Storage Temperature Range
-35 ºC to +100 ºC
Shock Resistance
50 g
Vibration Resistance (10 - 2000 Hz)
20 g
Soldering Temperature (max) (10 s max)
270 ºC
Washability (Proper drying process is recommended)
Fully Sealed
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pickeringrelay.com
Specification
Single Pole 4mm 2 ™ Reed Relays – Series 120
Dry Relay: Series 120 Coil data and type numbers
Device Type
Type Number
1 Form A, Switch No. 1
(*Note 15 W for 3 V coil)
Package Type 1
1 Form A
Switch No. 2
Package Type 1
‡
Coil
(V)
Max.
Coil
contact
resistance resistance
(initial)
120-1-A-3/1 *
3
200 Ω
120-1-A-5/1
5
300 Ω
12
800 Ω
120-1-A-3/2
3
200 Ω
120-1-A-5/2
120-1-A-12/2 ‡
5
12
500 Ω
800 Ω
120-1-A-12/1
‡
Insulation resistance
(minimum at 25 °C)
(see Note4)
Capacitance
(typical)
(see Note2, 3)
Switch
to coil
Across
switch
Closed
switch
to coil
Across
open
switch
0.18 Ω
1012 Ω
1012 Ω
2.9 pF
0.14 pF
0.18 Ω
1012 Ω
1012 Ω
2.9 pF
0.14 pF
See Note5 below.
Note2: Switch to coil capacitance
Due to the asymmetrical internal construction of the relay, the capacitance to the coil from one switch connection is
approximately half the capacitance of the other switch connection, pin 1 is lower. In some applications this feature may be
used to advantage for example, in a multiplexer where it is desirable to minimize the capacitance of the common connection
to maximize bandwidth.
Note3: Capacitance across open switch
The capacitance across the open switch was measured with other connections guarded.
Note4: Insulation resistance
Insulation resistance will reduce at higher temperatures. For more information on temperature effects click here, or
contact Pickering for more in depth guidance.
Note5: 12 volt coil versions
With limited room inside small packages, it is not possible to achieve the high coil resistance figures that would be
preferred, without using extremely fine wire gauges. If these ultra-fine gauges were used, there would be a resultant risk
of poorer reliability due to the delicate nature of such wire. Reliability is of paramount importance to Pickering, so ultra fine
gauges are avoided. The heating effect from the coil (V2/R) will therefore be higher than for the 3 or 5 volt versions. For
example:
3 volt type: 200 Ohms = 45 mWatts
5 volt type: 300 Ohms = 83 mWatts
12 volt type: 800 Ohms = 180 mWatts
12 Volt versions are suitable for applications such as Multiplexers or Matrices where they are operated on a low duty cycle
but consideration should be made where they are left operated for longer due to this heating effect.
The technical information shown in this data sheet could contain inaccuracies or typographical errors. This information may
be periodically changed or updated and these changes will be included in future versions of this data sheet.
For different values, latest specifications and product details, please contact your local Pickering sales office.
For FREE evaluation samples go to: pickeringrelay.com/samples
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Specification
Single Pole 4mm 2 ™ Reed Relays – Series 120
Pin Configuration, Weights and Dimensional Data (dimensions in inches, millimeters in brackets)
0.153
(3.9)
Package
Type
Package
Type
11
0.153
(3.9)
Weight:
Typical0.49
0.49gg
Weight:
Typical
Cut away corner
indicates Pin 1
Pin
0.01
(0.25)
4
1 Form A
0.61
(15.5)
Pin
0.02
(0.5)
1
0.08
(2.0)
3
2
0.08
(2.0)
0.125
(3.2)
Connection details - viewed from underside
0.08
(2.0)
0.08
(2.0)
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pickeringrelay.com
Specification
Single Pole 4mm 2 ™ Reed Relays – Series 120
Similar Relays Comparison
If the Series 120 is unsuitable for your application, Pickering also manufactures two other series of reed relays with similar
characteristics, but in different package sizes.
Series Name
124-1-A
122-1-A
120-1-A
3.9 (0.153)
3.9 (0.153)
3.9 (0.153)
3.9 (0.153)
3.9 (0.153)
3.9 (0.153)
9.5 (0.375)
12.5 (0.492)
15.5 (0.61)
Package Volume
(mm3)
145
191
236
Typical Weights (g)
0.28
0.37
0.49
Contact
Configuration
1-A
(SPST)
1-A
(SPST)
1-A
(SPST)
Physical Outline
Depth
Width
Height
mm
(inches)
1
Reed Switch Type
Dry
Dry
Dry
Dry
Switching Voltage
(V)
170
200
200
200
Switching Current
(A)
0.5
0.5
1.0
0.5
Carry Current
(A)
0.5
0.5
1.2
1.2
Switch Power
(W)
10
10
20/15
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Reed Relay Selection Tool
Because Pickering offer the largest range of high-quality reed relays, sometimes it can be difficult to find the right reed relay
you require. That is why we created the Reed Relay Selector, this tool will help you narrow down our offering to get you the
correct reed relay for your application. To try the tool today go to: pickeringrelay.com/reed-relay-selector-tool
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Ordering Information
Single Pole 4mm 2 ™ Reed Relays – Series 120
Standard Build Options
The Series 120 Reed Relays are available with a number of standard build options to tailor them to your specific application.
These options are detailed in the table below. If you decide to go ahead and specify one, or more, of these options you will
be allocated a unique part number suffix.
Mechanical Build Options
Electrical Build Options
Special pin configurations or pin lengths
Different coil resistance
Special print with customer’s own part number or logo
Operate or de-operate time
Pulse capability
Enhanced specifications
Non-standard coil voltages and resistance figures
Special Life testing under customer’s specific load
conditions
Specific environmental requirements
Controlled thermal EMF possibility
Customization
If your specific requirements are not met by standard relay, or any of the standard build options, please speak to us to
discuss producing a customized reed relay to service your specific application: pickeringrelay.com/contact
3D Models
Interactive 3D models of the complete range of Pickering relay products in STEP, IGS and SLDPRT formats can be
downloaded from the website: pickeringrelay.com/3d-models
Part Number Description:
120 - 1 - A - 5 / 2 - xxx
Series
Number of reeds
Switch form
Coil voltage
Switch number (only Type 2 available)
Unique suffix (if standard build option selected)
Help
If you need any technical advice or other help, please do not hesitate to contact our Technical Sales Department. We will
always be pleased to discuss Pickering relays with you. email: techsales@pickeringrelay.com
Contact Us
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UK Headquarters - email: sales@pickeringrelay.com | Tel. +44 1255 428141
USA - email: ussales@pickeringrelay.com | Tel. +1 781 897 1710
Germany - email: desales@pickeringtest.com | Tel. +49 89 125 953 160
Product
France - email: frsales@pickeringtest.com | Tel. +33 9 72 58 77 00
25+Years 100%
Tested
Longevity
Nordic - email: ndsales@pickeringtest.com | Tel. +46 340 69 06 69
Czech Republic: czsales@pickeringtest.com | Tel. +420 558-987-613
China - email: chinasales@pickeringtest.com | Tel. +86 4008 799 765
For a full list of agents, distributors and representatives visit: pickeringrelay.com/agents
pickeringrelay.com
Single Pole 4mm 2 ™ Reed Relays – Series 120
10 Key Benefits of Pickering Reed Relays
Pickering Reed Relays
Typical Industry Reed Relays
Instrumentation Grade Reed Switches
with vacuum sputtered Ruthenium
plating to ensure stable, long life up to
5x10E9 operations.
Often low grade Reed Switches with
electroplated Rhodium plating resulting
in higher, less stable contact resistance.
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Formerless Coil
Construction
Formerless coil construction increases
the coil winding volume, maximizing
magnetic efficiency, allowing the use of
less sensitive reed switches resulting in
optimal switching action and extended
lifetime at operational extremes.
Use of bobbins decreases the coil
winding volume, resulting in having
less magnetic drive and a need to use
more sensitive reed switches which
are inherently less stable with greatly
reduced restoring forces.
3
Magnetic Screening
Mu-metal magnetic screening (either
external or internal), enables ultra-high
PCB side-by-side packing densities with
minimal magnetic interaction, saving
significant cost and space. Pickering
Mu-Metal magnetic screen - interaction
approx. 5%
Lower cost reed relays have minimal
or no magnetic screening, resulting in
magnetic interaction issues causing
changes in operating and release
voltages, timing and contact resistance,
causing switches to not operate at their
nominal voltages. Typical industry
screen - interaction approx. 30%
4
SoftCenter™ technology, provides
maximum cushioned protection of the
reed switch, minimising internal lifetime
stresses and extending the working life
and contact stability.
Transfer moulded reed relays (produced
using high temperature/pressure),
result in significant stresses to the glass
reed switch which can cause the switch
blades to deflect or misalign leading to
changes in the operating characteristics,
contact resistance stability and operating
lifetime.
100% testing for all operating
parameters including dynamic contact
wave-shape analysis with full data
scrutiny to maintain consistency.
Simple dc testing or just batch testing
which may result in non-operational
devices being supplied.
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Instrumentation Grade
Reed Switches
SoftCenter™
Technology
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100% Dynamic
Testing
X-Ray of Pickering
mu-metal
magnetic screen
X-Ray of typical
industry
magnetic screen
Dynamic Contact Resistance Test
Operate
Contact Resistance
Key Benefit
Release
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100% Inspection
at Every Stage of
Manufacturing
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Inspection at every stage of
manufacturing maintaining high levels
of quality.
Often limited batch inspection.
Stress testing of the manufacturing
processes, from -20°C to +85°C to -20°C,
repeated 3 times.
Rarely included resulting in field failures.
+85°C
100% Thermal
Cycling
-20°C
Product Longevity
Limited ability to customize.
Pickering are committed to product
longevity; our reed relays are
manufactured and supported for
more than 25 years from introduction,
typically much longer.
Most other manufacturers discontinue
parts when they reach a low sales
threshold; costing purchasing and R&D
a great deal of unnecessary time and
money to redesign and maintain supply.
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Our reed relays can be customized
easily, e.g. special pin configurations,
enhanced specifications, non-standard
coil or resistance figures, special life
testing, low capacitance, and more.
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Mass production: Usually large
batch sizes and with no quick-turn
manufacturing.
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Custom Reed Relays
Flexible manufacturing processes allow
quick-turn manufacturing of small
batches.
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Flexible
Manufacturing
Process
Product
25+Years
Longevity
For more information go to: pickeringrelay.com/10-key-benefits
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© Copyright (2022) Pickering Electronics. All Rights Reserved
Pickering Electronics maintains a commitment to continuous product development, consequently we reserve the right to vary from the description given in this data sheet.
Coil Voltage