tfdu6108 Vishay, tfdu6108 Datasheet - Page 7

• Manufacturer Part Number: tfdu6108
• Description: Fast Infrared Transceiver Module 4 Mbit/s , Irda Serial Interface Compatible, 2.7 V To 5.5 V Supply Voltage Range
• Manufacturer: Vishay

Recommended Circuit Diagram
Operated with a low impedance power supply the
TFDU6108 needs no external components. However,
depending on the entire system design and board lay-
out, additional components may be required (see fig-
ure 1).
Vishay Semiconductor transceivers integrate a sensi-
tive receiver and a built-in power driver. The combina-
tion of both needs a careful circuit board layout. The
use of thin, long, resistive and inductive wiring should
be avoided. The inputs (Txd, SCLK) and the output
Rxd should be directly (DC) coupled to the I/O circuit.
R1 is used for controlling the maximum current
through the IR emitter. This one is necessary when
operating over the full range of operating temperature
and V
max. output power of the IRED, the value of the resis-
tor should be reduced. It should be dimensioned to
keep the IRED anode voltage below 4 V for using the
full temperature range. For device and eye protection
the pulse duration and current are internally limited.
R2, C1 and C2 are optional and dependent on the
quality of the supply voltage V
An unstable power supply with dropping voltage dur-
ing transmission may reduce sensitivity (and trans-
mission range) of the transceiver.
The placement of these parts is critical. It is strongly
recommended to position C2 close to the transceiver
power supply pins. An electrolytic capacitor should be
used for C1 while a ceramic capacitor is used for C2.
Document Number 82537
Rev. 1.7, 13-May-05
SCLK
V
V
V
GND
Rxd
logic
CC2
CC1
Txd
CC1
Figure 1. Recommended Application Circuit
All external components (R, C) are optional
- voltages above 4 V. For increasing the
C1
R2
R1
C2
IRED
Cathode
Rxd
Vcc
GND
CC1
and injected noise.
Anode
SCLK
V
IRED
Txd
logic
17089
Recommended Application Circuit
Components
I/O and Software
For operating the device from a Controller I/O a driver
software must be implemented.
Mode Switching
The generic IrDA "Serial Interface programming"
needs no special settings for the device. Only the cur-
rent control table must be taken into account. For the
description see the Appendix and the IrDA "Serial
Interface specification for transceivers"
Component
C1
C2
R1
R2
Vishay Semiconductors
Recommended for V
Depending on current limit
Recommended Value
0.1 μF, Ceramic, 16V
47 Ω, 0.125 W
4.7 μF, 16 V
TFDU6108
www.vishay.com
CC1
≥ 4 V
7