STF201-30TC datasheet(4/7 Pages) SEMTECH

Teilenummer	STF201-30TC

Bauteilbeschribung	USB Downstream Post Filter & TVS For EMI Filtering and ESD Protection

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Hersteller	SEMTECH [Semtech Corporation]

Direct Link	http://www.semtech.com

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ã 2000 Semtech Corp.

www.semtech.com

PROTECTION PRODUCTS

STF201-22 & STF201-30

Figure 1 - STF201 Circuit Diagram

Device Connection

The STF201 is designed to provide termination, EMI

filtering and ESD protection for two USB I/O lines. The

equivalent circuit diagram is shown in Figure 1. The

device is connected as follows:

l

USB data lines are routed through the STF201 for

easy implementation and optimum pc board layout.

Pin 1 is connected to the voltage supply line. The

input of the D+ line is routed into pin 2 and out of

pin 5. The input of the D- line is connected at pin 3

and the output at pin 4. Pin 6 is connected to

ground. The ground connection should be made

directly to the ground plane for best results. The

path length is kept as short as possible to reduce

the effects of parasitic inductance in the board

traces.

USB Port Design Considerations

The Universal Serial Bus (USB) specification requires

termination and filtering components for proper opera-

tion. In addition, an open USB socket is vulnerable to

hazardous ESD discharges in excess of 15kV. These

discharges can may occur on the data lines or the

voltage bus. The STF201 is an easily implemented

solution designed to meet the termination & EMI filter

requirements of the USB specification revision 1.1. It

also provides ESD protection to IEC 61000-4-2, level

4.

A simplified USB port is shown in Figure 3. USB line

termination is achieved with series resistors on both

the D+ and D- lines. These resistors preserve signal

integrity by matching the cable impedance to that of

the differential driver. 15kW pull-down resistors are

used to identify a downstream port while an upstream

port is identified with a 1.5KW pull up resistor on either

the D+ (full speed devices) or the D- (low speed de-

vices) data line. Capacitors are used to bypass high

frequency energy to ground and for edge rate control

of the USB signals. TVS diodes are added for ESD

protection of both (D+ & D-) data lines and the voltage

bus (V

BUS). A power distribution switch and voltage

regulator provide the power management functions of

the port.

Semtech provides a complete solution to simplify USB

port design (Figure 4). The STF201 & STF202 inte-

Figure 2 - STF201 Connection Diagram

1

2

34

5

6

grate all of the components necessary for line termina-

tion, bidirectional EMI filtering, and ESD protection on

downstream (STF201) or upstream (STF202) ports.

The SC5826 is a dual port power switch that provides

individual or ganged port switching, fault reporting, and

inrush current limiting as required by the USB specifica-

tion. The SC5205 ULDO provides a stable voltage to

the USB controller.

Board Placement & layout Guidelines.

Board layout and placement of the STF201 play a

critical role in EMI & ESD suppression. Designing a

USB hub to meet EMI & ESD immunity requirements

requires a combination of optimum component place-

ment, trace routing, and good circuit design practices.

Some general guidelines are given below:

l

Avoid running D+ & D- signal line traces near high

speed clock lines or similar signal lines.

l

Avoid running critical signal lines near board edges.

l

Locate the USB controller chip physically near the

USB connectors.

l

Place the STF201 near the USB connector to

restrict transient coupling.

l

Minimize the path length between the USB connec-

tor and the STF201 as well as between the USB

controller and the STF201.

Applications Information

Ähnliche Beschreibung - STF201-30TC

Hersteller	Teilenummer	Datenblatt	Bauteilbeschribung
Semtech Corporation	ECLAMP2122S	229Kb / 7P	USB Downstream Port Filter & TVS For EMI Filtering and ESD Protection
	STF202-22	164Kb / 6P	USB Upstream Port Filter & TVS For EMI Filtering and ESD Protection
	ECLAMP2522P	198Kb / 7P	USB Upstream Port Filter and TVS For EMI Filtering and ESD Protection
KEC(Korea Electronics)	PF1714WLP15	434Kb / 1P	For EMI Filtering and ESD Protection.
KEC(Korea Electronics)	PF1710WLP15	434Kb / 1P	For EMI Filtering and ESD Protection.
Semtech Corporation	STF701	173Kb / 6P	T-Filter with TVS Diode Array For EMI Filtering and ESD Protection
California Micro Device...	PACUSB200	40Kb / 2P	USB DUAL DOWNSTREAM PORT FILTER WITH ESD PROTECTION
KEC(Korea Electronics)	PF0224TE6	432Kb / 1P	EMI Filtering TVS For USB Port
KEC(Korea Electronics)	PF0314TE6	432Kb / 1P	EMI Filtering TVS For USB Port
Semtech Corporation	STF201-22	181Kb / 7P	USB Downstream Port Filter & TVS

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