TFBS6712-TR3 Vishay, TFBS6712-TR3 Datasheet - Page 7

• Manufacturer Part Number: TFBS6712-TR3
• Description: Infrared Transceivers FIR 4Mbit/s 2.4-3.6V Op Voltage
• Manufacturer: Vishay

Specifications of TFBS6712-TR3

• Wavelength: 900 nm
• Continual Data Transmission: 4 Mbit/s
• Transmission Distance: 50 cm
• Radiant Intensity: 115 mW/sr
• Half Intensity Angle Degrees: 48 deg
• Pulse Width: 1.8 us
• Maximum Rise Time: 50 ns, 40 ns
• Maximum Fall Time: 50 ns, 40 ns
• Led Supply Voltage: - 0.5 V to 6.5 V
• Operating Voltage: 2.4 V to 3.6 V
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 25 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

TFBS6712
Vishay Semiconductors
Recommended Circuit Diagram
Operated at a clean low impedance power supply the
TFBS6712 needs no additional external components.
However, depending on the entire system design and
board layout, additional components may be required
(see figure 3).
The capacitor C1 is buffering the supply voltage and
eliminates the inductance of the power supply line.
This one should be a Tantalum or other fast capacitor
to guarantee the fast rise time of the IRED current.
Vishay 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) and the output RXD should be
directly (DC) coupled to the I/O circuit.
The capacitor C2 combined with the resistor R2 is the
low pass filter for smoothing the supply voltage.
R2, C1 and C2 are optional and dependent on the
quality of the supply voltages V
noise. An unstable power supply with dropping volt-
age during transmission may reduce the sensitivity
(and transmission range) of the transceiver.
The placement of these parts is critical. It is strongly
recommended to position C2 as close as possible to
the transceiver power supply pins.
www.vishay.com
276
SD
TXD
RXD
V
V
GND
CC2
CC1
Figure 3. Recommended Application Circuit
C1
R2
R1
C2
SD
TXD
RXD
IRED Anode
V
Ground
CC
CCx
19430
and injected
A Tantalum capacitor should be used for C1 while a
ceramic capacitor is used for C2.
In addition, when connecting the described circuit to
the power supply, low impedance wiring should be
used.
When extended wiring is used the inductance of the
power supply can cause dynamically a voltage drop
at V
follow the fast current rise time. In that case another
4.7 µF (type, see tavle under C1) at V
ful.
Keep in mind that basic RF-design rules for circuit
design should be taken into account. Especially
longer signal lines should not be used without termi-
nation. See e.g. "The Art of Electronics" Paul Horo-
witz, Winfield Hill, 1989, Cambridge University Press,
ISBN: 0521370957.
Table 1. Recommended Application Circuit Compo-
nents
I/O and Software
In the description, already different I/Os are men-
tioned. Different combinations are tested and the
function verified with the special drivers available
from the I/O suppliers. In special cases refer to the I/
O manual, the Vishay application notes, or contact
directly Vishay Sales, Marketing or Application.
Component
CC2
C1
C2
R1
R2
. Often some power supplies are not able to
3.3 V supply voltage: no resistor necessary, the
internal controller is able to control the current
VJ1 206 Y 104 J XXMT
Recommended Value
293D 475X9 016B
0.1 µF, Ceramic
4.7 Ω, 0.125 W
Vishay part#:
Vishay part#:
4.7 µF, 16 V
Document Number 84674
Rev. 1.2, 21-Feb-07
CC2
will be help-