1840

Features
■ Low peak clamping voltage even during
■ Cable shields are passed through and
severe current surges
■ Ability to repeatedly protect against high
surge currents up to rated limits
■ Convenient mounting and grounding to any
flat surface or to DIN-1 (TS-32) or DIN-3
(TS-35) rail
may be either grounded or arc-protected to
ground
■ Vibration-resistant screw-type clamp
terminals
■ Flame-resistant epoxy-filled housing
1840 Series – Signal and Dataline Protector
The Bourns® 1840 Series Signal and Dataline Protectors are designed to protect sensitive electronic circuits and components from damaging
surge voltages and currents. Their extremely fast response and low clamping voltages make them particularly suitable for the protection of sensitive signal and datalines associated with computer, data communication, instrumentation, broadcasting and industrial controls. They may be used
directly with EIA standard interfaces RS-232, RS-422, RS-423, RS-485 and with 4-20 mA and 50 mA instrumentation loops. The Model 1840
Series Signal and Dataline Protectors are fast, rugged and capable of protecting against fast rising voltage transients as well as the severe
current surges associated with lightning discharges, in each case up to rated limits.
Method of Operation
The Bourns® 1840 Series are heavy-duty, multi-staged protectors. A solid-state 3rd stage protection component intercepts the leading edge of the
surge within sub-nanosecond response time. Within microseconds, a primary stage 3-electrode common chambered heavy-duty gas discharge
tube capable of handling 20,000 ampere lightning currents operates and crowbars the majority of the surge energy to ground. The Model 1840
also utilizes Bourns’ TBU® High-Speed Protector (HSP) technology as a key 2nd stage. Any current through the protector exceeding 300 mA
will cause the TBU® HSP to quickly transition into a high impedance state, thus isolating any harmful voltage and/or current from damaging the
protected equipment. The gas discharge tube protector remains in the crowbar state until the surge has passed and line voltages return to safe
levels. The TBU® HSP then automatically restores the line to normal operation by resetting to a low impedance state. There is no need for
resetting a breaker or replacing a fuse to address a transient surge event.
Application
Protectors are generally placed at each end of a signal, dataline or current loop. In the case of daisy-chain configurations (such as RS-485),
protectors are placed at each node.
Related Bourns® Protectors
For outdoor applications with 1/2-inch NPT ports (such as field-mounted 4-20 mA transmitters), please refer to the Bourns® Model 1669 Series
Protector. In this application, the mixed use of a Model 1840 Series Protector at the controller and a Model 1669 Series Protector at the field is
recommended.
Circuit Diagram
1840-05
1840-12
L1
1840-24
Maximum Operating Voltage
6 Vdc
13 Vdc
26 Vdc
Maximum Breakdown Voltage
(L-L) and (L-G)
8 Vdc
15 Vdc
30 Vdc
L2
Surge Life
100 Amps 10 x 1000 μsec............................................
100 Amps 10 x 1000 μsec............................................
500 Amps 10 x 1000 μsec............................................
1000 Amps 10 x 1000 μsec..........................................
3 kA, 6 kV / 8 x 20 μsec Combination Wave ................
10 kA / 8 x 20 μsec.......................................................
20 kA / 8 x 20 μsec.......................................................
Breakdown Voltage............................................................
ESD @ 8 kV ......................................................................
Shield ARC Protection 6 kV / 3 kA.....................................
Capacitance @ 1 MHz ......................................................
Series Resistance..............................................................
Maximum Load Continuous Current ..................................
DC Leakage Current at Rated L/G Voltage .......................
Blocking Current ................................................................
Signal/Data Attenuation .....................................................
Operating Temperature......................................................
Response Time..................................................................
Wire Size ...........................................................................
TBU® DEVICE
LINE
Standard Model
TBU® DEVICE
E1
SOLID-STATE
LOW
VOLTAGE
PROTECTION
E2
E3
SHIELD
EQUIPMENT
Characteristics @ 25 °C
SHIELD
SHORTING
LINK
300 operations min.
300 operations min.
50 operations min.
10 operations min.
100 operations min.
10 operations min.
5 operations min.
See table*
10 operations min.
5 operations min.
L/G: 45 pF, L/L: 35 pF
12 Ω typical
220 mA
< 10 μA
300 mA; typical 450 mA
3 db @ 30 MHz with 50 Ω
termination
-40 ºC to +60 ºC
< 1 μsec
20 AWG
Asia-Pacific:
Tel: +886-2 2562-4117
Fax: +886-2 2562-4116
EMEA:
Tel: +36 88 520 390
Fax: +36 88 520 211
The Americas:
Tel: +1-951 781-5500
Fax: +1-951 781-5700
www.bourns.com
*Custom voltages are available upon request. Please visit www.bourns.com/data/global/
pdfs/SMBJ.pdf for custom allowable voltage. Lead-time may be extended for some custom
voltages.
Specifications are subject to change without notice.
The device characteristics and parameters in this data sheet can and do vary in different applications and actual device performance may vary over time.
Users should verify actual device performance in their specific applications.
1840 Series – Signal and Dataline Protector
Typical Connections
How To Order
1840 - nn - An
Unbalanced Interface, Two Individual Circuits, Such as RS-232
Model No. Designator
E2
P/N 1840
L2
E3
RCVR
E1
GND
EQPT. COMMON
AND/OR GND.
P/N 1840
L2
L3
L1
E2
GND
L1
RCVR
XMTR
E1
COMMON
GND.
COMMON
GND.
Voltage
05 = 5 Vdc
12 = 12 Vdc
24 = 24 Vdc
Clamp
A1 = DIN-1
A3 = DIN-3
E3
L3
~
~
XMTR
BLDG. 2
~
~
BLDG. 1
EQPT. COMMON
AND/OR GND.
How To Order (Clamp)
Add -A1 to base model number for
DIN-1 clamp.
(Example: 1840-12-A1)
Balanced or Differential Interface, Such as RS-422
XMTR
P/N 1840
L2
E3
E1
L2
P/N 1840
L1
L1
FEED-THRU(E3/L3)
E2
GROUNDING SCREW
E3
L3
L3
GND
~
~
E2
BLDG. 2
~
~
BLDG. 1
GND
RCVR
E1
28.96
(1.14)
EQPT. COMMON
AND/OR GND.
COMMON
GND.
COMMON
GND.
EQPT. COMMON
AND/OR GND.
49.02
(1.93)
DIN-1 RAIL
(TS-32/EN50035)
Current Loop, 4-20 mA
CONTROL ROOM
250
OHMS
E3
E1
~
~
P/N 1840
L2
RED
GND
L1
RED /WHITE
BLACK /WHITE
BOURNS
1669
L3
~
~
E2
POWER
SUPPLY
Add -A3 to base model number for
DIN-3 clamp.
(Example: 1840-12-A3)
XMTR
I
GREEN
MOUNTING/GROUNDING SCREW
BLK
File No.
1800SERS3
RECEIVER
1-5 VOLTS
+
-
I
BOURNS
PROTECTOR
P/N 1669
COMMON
GND.
45.47
(1.79)
Grounding: The 8-32 mounting screw and attached clamp, and hence the DIN-1 (TS-32)
or DIN-3 (TS-35) rail, serve as the protector ground. The rail (or 8-32 mounting screw if the
clamp is not used) should be connected to the facility ground via an AWG #6 or larger copper
wire. This wire should be as short and straight as possible. Single point grounding will provide
better protection and will permit the protector to be located a distance from the equipment.
DIN-3 RAIL
(TS-35/EN50022)
DIMENSIONS:
MM
(INCHES)
Product Dimensions
LINE
L1 L3 L2
EQPT
E2 E3 E1
GND
48.51
(1.91)
DIMENSIONS:
E3/L3 GROUNDING LINK
83.31
(3.28)
18.80
3.18
(0.74) (0.125)
2.36
(0.093)
ALIGNMENT PIN
MM
(INCHES)
9.53
(0.375)
8-32UNF-2A
17.80
(0.70)
LG
REV. B 07/15
Specifications are subject to change without notice.
The device characteristics and parameters in this data sheet can and do vary in different applications and actual device performance may vary over time.
Users should verify actual device performance in their specific applications.
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