Features

n Low peak clamping voltage even during

severe current surges

n Ability to repeatedly protect against high

surge currents up to rated limits

n Convenient mounting and grounding to any

ﬂat surface or to DIN-1 (TS-32) or DIN-3

(TS-35) rail

n Cable shields are passed through and

may be either grounded or arc-protected to

ground

n Vibration-resistant screw-type clamp

terminals

n Flame-resistant epoxy-ﬁlled housing

1840 Series – Signal and Dataline Protector

Speciﬁcations are subject to change without notice.

Users should verify actual device performance in their speciﬁc applications.

The products described herein and this document are subject to speciﬁc legal disclaimers as set forth on the last page of this document, and at www.bourns.com/docs/legal/disclaimer.pdf.

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 sensi-

tive 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 congurations (such as RS-485),

protectors are placed at each node.

Related Bourns

Protectors

For outdoor applications with 1/2-inch NPT ports (such as eld-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 eld is

recommended.

Characteristics @ 25 °C

Standard Model 1840-05 1840-12 1840-24

(1)

Maximum Operating Voltage 6 V

13 V

26 V

Maximum Breakdown Voltage (L-L) and (L-G) 8 V

15 V

30 V

(1)

Systems operating at 18 V or above and experiencing current above 500 mA (including short-term inrush current at start-up) may latch the

overcurrent protection feature in blocking mode. This will prevent system operation until the power is removed.

Surge Life

100 Amps 10 x 1000 µsec ........................................................................................................300 operations min.

500 Amps 10 x 1000 µsec ........................................................................................................50 operations min.

1000 Amps 10 x 1000 µsec ......................................................................................................10 operations min.

3 kA, 6 kV / 8 x 20 µsec Combination Wave ............................................................................100 operations min.

10 kA / 8 x 20 µsec ...................................................................................................................10 operations min.

20 kA / 8 x 20 µsec ...................................................................................................................5 operations min.

Breakdown Voltage.................................................................................................................................See table*

ESD @ 8 kV ...........................................................................................................................................10 operations min.

Shield ARC Protection 6 kV / 3 kA ..........................................................................................................5 operations min.

Capacitance @ 1 MHz ...........................................................................................................................L/G: 45 pF, L/L: 35 pF

Series Resistance...................................................................................................................................12 Ω typical

Maximum Load Continuous Current ....................................................................................................... 220 mA

DC Leakage Current at Rated L/G Voltage ............................................................................................< 10 µA

Blocking Current .....................................................................................................................................300 mA; typical 450 mA

Signal/Data Attenuation ..........................................................................................................................3 db @ 30 MHz with 50 Ω termination

Operating Temperature ...........................................................................................................................-40 ºC to +60 ºC

Response Time.......................................................................................................................................< 1 µsec

Wire Size ................................................................................................................................................20 AWG

* Custom voltages are available upon request. Please visit www.bourns.com/docs/Product-Datasheets/SMBJ.pdf for custom allowable

voltages.

Lead-time may be extended for some custom voltages.

File No.

1800SERS3

File No.

1800SERS2

P/N 1669

PROTECTOR

BOURNS

P/N 1840

P/N 1840P/N 1840

P/N 1840

BALANCED OR DIFFERENTIAL INTERFACE, SUCH AS RS-422

BLK

RED

XMTR

/WHITE

GREEN

BLACK

RED

1669

BOURNS

CONTROL ROOM

SUPPLY

POWER

OHMS

250

1-5 VOLTS

RECEIVER

CURRENT LOOP, 4-20 mA

UNBALANCED INTERFACE, TWO INDIVIDUAL CIRCUITS, SUCH AS RS-232

GND.

COMMON

AND/OR GND.

EQPT. COMMON

XMTR

GND

RCVR

GND

COMMON

GND.

GND

XMTR

EQPT. COMMON

AND/OR GND.

COMMON

GND.

BLDG. 1 BLDG. 2

BLDG. 2BLDG. 1

RCVR

GND

EQPT. COMMON

AND/OR GND.

COMMON

GND.

P/N 1840

GND.

COMMON

AND/OR GND.

EQPT. COMMON

XMTR

GND

Typical Connections

Unbalanced Interface, Two Individual Circuits, Such as RS-232

Speciﬁcations are subject to change without notice.

Users should verify actual device performance in their speciﬁc applications.

The products described herein and this document are subject to speciﬁc legal disclaimers as set forth on the last page of this document, and at www.bourns.com/docs/legal/disclaimer.pdf.

1840 Series – Signal and Dataline Protector

File No.

1800SERS3

File No.

1800SERS2

P/N 1669

PROTECTOR

BOURNS

P/N 1840

P/N 1840P/N 1840

P/N 1840

BALANCED OR DIFFERENTIAL INTERFACE, SUCH AS RS-422

BLK

RED

XMTR

/WHITE

GREEN

BLACK

RED

1669

BOURNS

CONTROL ROOM

SUPPLY

POWER

OHMS

250

1-5 VOLTS

RECEIVER

CURRENT LOOP, 4-20 mA

UNBALANCED INTERFACE, TWO INDIVIDUAL CIRCUITS, SUCH AS RS-232

GND.

COMMON

AND/OR GND.

EQPT. COMMON

XMTR

GND

RCVR

GND

COMMON

GND.

GND

XMTR

EQPT. COMMON

AND/OR GND.

COMMON

GND.

BLDG. 1 BLDG. 2

BLDG. 2BLDG. 1

RCVR

GND

EQPT. COMMON

AND/OR GND.

COMMON

GND.

P/N 1840

GND.

COMMON

AND/OR GND.

EQPT. COMMON

XMTR

GND

Balanced or Differential Interface, Such as RS-422

File No.

1800SERS3

File No.

1800SERS2

P/N 1669

PROTECTOR

BOURNS

P/N 1840

P/N 1840P/N 1840

P/N 1840

BALANCED OR DIFFERENTIAL INTERFACE, SUCH AS RS-422

BLK

RED

XMTR

/WHITE

GREEN

BLACK

RED

1669

BOURNS

CONTROL ROOM

SUPPLY

POWER

OHMS

250

1-5 VOLTS

RECEIVER

CURRENT LOOP, 4-20 mA

UNBALANCED INTERFACE, TWO INDIVIDUAL CIRCUITS, SUCH AS RS-232

GND.

COMMON

AND/OR GND.

EQPT. COMMON

XMTR

GND

RCVR

GND

COMMON

GND.

GND

XMTR

EQPT. COMMON

AND/OR GND.

COMMON

GND.

BLDG. 1 BLDG. 2

BLDG. 2BLDG. 1

RCVR

GND

EQPT. COMMON

AND/OR GND.

COMMON

GND.

P/N 1840

GND.

COMMON

AND/OR GND.

EQPT. COMMON

XMTR

GND

Current Loop, 4-20 mA

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.

How To Order (Clamp)

Add -A1 to base model number for

DIN-1 clamp.

(Example: 1840-12-A1)

Add -A3 to base model number for

DIN-3 clamp.

(Example: 1840-12-A3)

(TS-35/EN50022)

DIN-3 RAIL

(TS-32/EN50035)

DIN-1 RAIL

E3/L3 GROUNDING LINK

MOUNTING/GROUNDING SCREW

GROUNDING SCREW

FEED-THRU(E3/L3)

GND

EQPT

E2 E3 E1

LINE

L1 L3 L2

45.47

(1.79)

49.02

(1.93)

28.96

(1.14)

ALIGNMENT

8-32UNF-2A

9.53

(0.375)

3.18

(0.125)

2.36

(0.093)

17.80

(0.70)

48.51

(1.91)

18.80

(0.74)

83.31

(3.28)

LINE

EQUIPMENT

SHIELD

SHORTING

LINK

TBU

DEVICE

TBU

DEVICE

SHIELD

SOLID-STATE

LOW

VOLTAGE

PROTECTION

(TS-35/EN50022)

DIN-3 RAIL

(TS-32/EN50035)

DIN-1 RAIL

E3/L3 GROUNDING LINK

MOUNTING/GROUNDING SCREW

GROUNDING SCREW

FEED-THRU(E3/L3)

GND

EQPT

E2 E3 E1

LINE

L1 L3 L2

45.47

(1.79)

49.02

(1.93)

28.96

(1.14)

ALIGNMENT

8-32UNF-2A

9.53

(0.375)

3.18

(0.125)

2.36

(0.093)

17.80

(0.70)

48.51

(1.91)

18.80

(0.74)

83.31

(3.28)

LINE

EQUIPMENT

SHIELD

SHORTING

LINK

TBU

DEVICE

TBU

DEVICE

SHIELD

SOLID-STATE

LOW

VOLTAGE

PROTECTION

DIMENSIONS:

(INCHES)

How To Order

1840 - nn - An

Model No. Designator

Voltage

05 = 5 V

12 = 12 V

24 = 24 V

Clamp

A1 = DIN-1

A3 = DIN-3

(TS-35/EN50022)

DIN-3 RAIL

(TS-32/EN50035)

DIN-1 RAIL

E3/L3 GROUNDING LINK

MOUNTING/GROUNDING SCREW

GROUNDING SCREW

FEED-THRU(E3/L3)

GND

EQPT

E2 E3 E1

LINE

L1 L3 L2

45.47

(1.79)

49.02

(1.93)

28.96

(1.14)

ALIGNMENT

8-32UNF-2A

9.53

(0.375)

3.18

(0.125)

2.36

(0.093)

17.80

(0.70)

48.51

(1.91)

18.80

(0.74)

83.31

(3.28)

LINE

EQUIPMENT

SHIELD

SHORTING

LINK

TBU

DEVICE

TBU

DEVICE

SHIELD

SOLID-STATE

LOW

VOLTAGE

PROTECTION

Circuit Diagram