422ELC_10 Datasheet, PDF (1/5 Pages) Protek Devices – DIGITAL PROCESS DATA LINE PROTECTOR

Only One Name Means ProTek’Tion™
DIGITAL PROCESS DATA LINE PROTECTOR
422ELC
422elc
Description
The 422ELC is low capacitance, two-stage transient voltage protector that provides primary and secondary protec-
tion against lightning, inductive switching and electrostatic discharge (ESD) transient threats. The first stage diverts
the transient current through the ground terminal return path and the second stage clamps the voltage to a safe level
without interruption of service.
The 422ELC is designed to protect data lines from differential (line-line) and common-mode (line-to-ground) transients.
Terminals 1 & 2 and 3 & 4 for the 422ELC are designed as line pairs. A transient voltage suppressor is connected
across each line pair for differential mode protection. Each line pair is referenced to ground.
This product can also be used on telephone, signal/data lines, security, timing and control interface circuits. For most
applications, the product should be located as close as possible to the equipment being protected. A low impedance
grounding system is important to maintain a low voltage clamp between the line-to-ground connection. Capacitance
over the operating voltage range is important. If capacitance is nonlinear, distortion, loss of data or access to the I/O
port can occur (See Figure 1).
applications
• RS-422 Data Lines
• Digital Process Control Loop
• Long Line Digital Systems
• Digital Transmission
• Telemetry Systems
• Smoke Detector and Fire Alarm Systems
Features
• Compatible with IEC 61000-4-2 (ESD): Air - 15kV, Contact - 8kV
• Compatible with IEC 61000-4-4 (EFT): 40A - 5/50ns
• Compatible with IEC 61000-4-5 (Surge): 95A, 8/20µs, Level 4 (Line-
Gnd) & 48A, Level 4 (Line-Line)
• Low Capacitance - 25pF
• Designed for EIA Standard RS-422 Data Lines
• Permanent Two-Stage 2 Line Pair Protector
• Subnanosecond Response Time
• Common & Differential Mode Protection
• Automatic Reset - Does Not Interrupt Service
• Effective Against Lightning, Inductive Switching and ESD
Mechanical characteristics
• Approximate Weight: 142 grams
• Flammability Rating UL 94V-0
figure 1
typical low capacitance curve
1,000
Industry
Standard Low
Capacitance TVS
Protector
100
ProTek Device
10
0
1
2
3
4
5
V_(OP) - Circuit Operating - Volts
05038.R4 12/10
Page 1
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