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Document Number 82541

Rev. 1.8, 05-Dec-05

TFDU4202

Vishay Semiconductors

Application Hints

The TFDU4202 does not need any external compo-

nent when operated with a "clean" power supply. In a

more noisy ambient it is recommended to add a

capacitor C1 and a resistor R1 for noise suppression.

A combination of a tantalum with a ceramics capacitor

will be efficient to attenuate both, RF and LF. The

550 mA current with a fast rise time. If that cannot be

should be included. The value is depended on the

power supply quality. A good choice between 4.7 µF

and 10 µF.

Shut down

The TFDU4202 can be shut down (disabled) by set-

when the devices are in shut down mode. The TXD

input is high impedance in shut down mode.

Latency

The receiver is in specified conditions after the

defined latency. In a UART related application after

that time (typically 50 µs) the receiver buffer of the

UART must be cleared. Therefore the transceiver has

to wait at least the specified latency after receiving the

last bit before starting the transmission to be sure that

the corresponding receiver is in a defined state.

For more application circuits, see IrDC Design Guide

and TOIM4232 data sheet.

Recommended Circuit Diagram

Table

Recommended Application Circuit Components

This is a recommendation for a combination to start with to exclude power supply effects.

Optimum, from a costs point of view, to work without both.

R1

Vccp

RXD

C1

GND

TXD

5, 6

8

3

7

4

GND

RXD

TXD

R2

1, 2 IRED Cathode

18187

Component

Recommended Value

Vishay Part Number

C1

4.7 µF, 16 V

293D 475X9 016B 2T

R1

5

Ω ( 2 Ω to 47 Ω)