422ELC Datasheet, PDF (1/3 Pages) Protek Devices – DIGITAL PROCESS DATA LINE PROTECTOR

Only One Name Means ProTek’Tion™
422ELC
DIGITAL PROCESS DATA LINE PROTECTOR
APPLICATIONS
✔ RS-422 Data Lines
✔ Digital Process Control Loop
✔ Long Line Digital Systems
✔ Digital Transmission
✔ Telemetry Systems
✔ Smoke Detector & Fire Alarm Systems
IEC COMPATIBILITY (EN61000-4)
✔ 61000-4-2 (ESD): Air - 15kV, Contact - 8kV
✔ 61000-4-4 (EFT): 40A - 5/50ns
✔ 61000-4-5 (Surge): 8/20µs - 95A, Level 4 (Line-Gnd) & 48A, Level 4 (Line-Line)
FEATURES
✔ 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
✔ Weight: 142 grams (Approximate)
✔ Flammability Rating UL 94V-0
✔ Device Marking: Logo, Date Code, Terminal Designations & Part Number
DESCRIPTION
The 422ELC is low capacitance, two-stage transient voltage protector that provides
primary and secondary protection against lightning, inductive switching and electro-
static 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).
1,000
422ELC
FIGURE 1
LINEAR CAPACITANCE VS
NON-LINEAR CAPACITANCE
Industry Standard
Low Capacitance
Solid State Protector
100
ProTek’s 422ELC
1,0
0
2
4
6
8
10
V_OP - Data Line Operating Voltage - Volts
05038.R3 11/03
1
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