TFDU6101E Datasheet, PDF (8/17 Pages) Vishay Siliconix – Fast Infrared Transceiver Module Family (FIR, 4 Mbit/s) for 2.6 V to 5.5 V Operation

TFDU6101E/TFDS6401/TFDS6501E/TFDT6501E
Vishay Semiconductors
Recommended Circuit Diagram
The only required component for designing an
IrDA 1.3 solution using Vishay Telefunken
transceivers is a current limiting resistor, R1, to the
IRED. However, depending on the entire system
design and board layout, additional components may
be required (see figure KEIN MERKER).
V_CC2
V_CC1
Rxd
GND
R1
R2
C1 C2
IRED
Cathode
IRED
Anode
Rxd
Txd
TFDx6x0xE
Vcc
SD/Mode
GND
Mode
SD/Mode
Txd
Note: outlined components are optional depending
on the quality of the power supply
Figure 3. Recommended Application Circuit
Vishay Telefunken transceivers integrate a sensitive
receiver and a built-in power driver. The combination
of both needs a careful circuit board layout. The use of
thin, long, resistive and inductive wiring should be
avoided. The inputs (Txd, SD/ Mode) and the output
Rxd should be directly (DC) coupled to the I/O circuit.
R1 is used for controlling the current through the
IR emitter. For increasing the output power of the
IRED, the value of the resistor should be reduced.
Similarly, to reduce the output power of the IRED, the
value of the resistor should be increased. For typical
values of R1 see figure 4. For IrDA compliant
operation, a current control resistor of 7.2 Ω is
recommended. For compensating losses of the cos-
metic window, reducing that value to 5.6 Ω is
acceptable. The upper drive current limitation is
dependent on the duty cycle and is given by the
absolute maximum ratings on the data sheet.
R2, C1 and C2 are optional and dependent on the
quality of the supply voltage V_CC and injected noise.
An unstable power supply with dropping voltage during
transmission may reduce sensitivity (and transmission
range) of the transceiver.
The placement of these parts is critical. It is strongly
recommended to position C2 as near as possible to the
transceiver power supply pins. An electrolytic
capacitor should be used for C1 while a ceramic
capacitor is used for C2.
Table 1. Recommended Application Circuit Components
Component
Recommended Value
C1
4.7 mF, Tantalum
C2
0.1 µF, Ceramic
R1
5 V supply voltage: 7.2 Ω , 0.25 W
(recommend using
two 3.6 W, 0.125 W resistors in series)
3.3 V supply voltage: 3.6 Ω , 0.25 W
(recommend using
two 1.8 W, 0.125 W resistors in series)
R2
47 Ω , 0.125 W
Vishay Part Number
293D 475X9 016B 2T
VJ 1206 Y 104 J XXMT
CRCW–1206–3R60–F–RT1
CRCW–1206–1R80–F–RT1
CRCW–1206–47R0–F–RT1
www.vishay.com
8 (17)
Document Number 82525
Rev. B1.6, 02–Nov–00