SRV05-4(2004) View Datasheet(PDF) - Semtech Corporation

Part Name

Description

Manufacturer

SRV05-4
(Rev.:2004)

RailClamp® Low Capacitance TVS Diode Array

Semtech Corporation 

SRV05-4

PROTECTION PRODUCTS

Applications Information

Device Connection Options for Protection of Four

High-Speed Data Lines

The SRV05-4 TVS is designed to protect four data lines

from transient over-voltages by clamping them to a

fixed reference. When the voltage on the protected

line exceeds the reference voltage (plus diode VF) the

steering diodes are forward biased, conducting the

transient current away from the sensitive circuitry.

Data lines are connected at pins 1, 3, 4 and 6. The

negative reference (REF1) is connected at pin 2. This

pin should be connected directly to a ground plane on

the board for best results. The path length is kept as

short as possible to minimize parasitic inductance.

The positive reference (REF2) is connected at pin 5.

The options for connecting the positive reference are

as follows:

1. To protect data lines and the power line, connect

pin 5 directly to the positive supply rail (VCC). In this

configuration the data lines are referenced to the

supply voltage. The internal TVS diode prevents

over-voltage on the supply rail.

2. The SRV05-4 can be isolated from the power

supply by adding a series resistor between pin 5

and VCC. A value of 100kΩ is recommended. The

internal TVS and steering diodes remain biased,

providing the advantage of lower capacitance.

3. In applications where no positive supply reference

is available, or complete supply isolation is desired,

the internal TVS may be used as the reference. In

this case, pin 5 is not connected. The steering

diodes will begin to conduct when the voltage on

the protected line exceeds the working voltage of

the TVS (plus one diode drop).

Data Line and Power Supply Protection Using Vcc as

reference

Data Line Protection with Bias and Power Supply

Isolation Resistor

Data Line Protection Using Internal TVS Diode as

Reference

ESD Protection With RailClamps

RailClamps are optimized for ESD protection using the

rail-to-rail topology. Along with good board layout,

these devices virtually eliminate the disadvantages of

using discrete components to implement this topology.

Consider the situation shown in Figure 1 where dis-

crete diodes or diode arrays are configured for rail-to-

rail protection on a high speed line. During positive

duration ESD events, the top diode will be forward

biased when the voltage on the protected line exceeds

 2004 Semtech Corp.

5

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