TFBS4650-TR3 Vishay, TFBS4650-TR3 Datasheet - Page 6

• Manufacturer Part Number: TFBS4650-TR3
• Description: Infrared Transceivers SIR 115.2 kbits/s 2.4-3.6V Op Voltage
• Manufacturer: Vishay

Specifications of TFBS4650-TR3

• Wavelength: 886 nm
• Continual Data Transmission: 115.2 Kbit/s
• Transmission Distance: 50 cm
• Radiant Intensity: 25 mW/sr
• Pulse Width: 2 us
• Maximum Rise Time: 100 ns
• Maximum Fall Time: 100 ns
• Operating Voltage: 2.4 V to 3.6 V
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 25 C
• Dimensions: 6.8 mm x 2.8 mm x 1.6 mm
• Data Rate: 115.2kbs (SIR)
• Idle Current, Typ @ 25° C: 75µA
• Link Range, Low Power: 50cm
• Operating Temperature: -25°C ~ 85°C
• Orientation: Side View
• Shutdown: *
• Size: 6.8mm x 2.8mm x 1.6mm
• Standards: IrPHY 1.4
• Supply Voltage: 2.4 V ~ 3.6 V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

TFBS4650
Vishay Semiconductors
RECOMMENDED CIRCUIT DIAGRAM
Operated at a clean low impedance power supply the
TFBS4650 needs only one additional external component
when the IRED drive current should be minimized for
minimum current consumption according the low power IrDA
standard. When combined operation in IrDA and remote
control
recommended.
However, depending on the entire system design and board
layout, additional components may be required (see fig. 1).
When long wires are used for bench tests, the capacitors are
mandatory for testing rise/fall time correctly.
The capacitor C1 is buffering the supply voltage V
eliminates the inductance of the power supply line. This one
should be a small ceramic version or other fast capacitor to
guarantee the fast rise time of the IRED current. The resistor
R1 is necessary for controlling the IRED drive current when
the internally controlled current is too high for the application.
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.
As already stated above R2, C1 and C2 are optional and
www.vishay.com
6
TABLE 1 - TRUTH TABLE
High
Low
Low
Low
Low
Low
SD
V
V
GND
SD
TXD
RXD
is
CC2
CC1
Fig. 1 - Recommended Application Circuit
intended
C1
High > 50 µs
no
R1
R2
[e-mail], [e-mail],
TXD
High
Low
Low
Low
x
For technical questions within your region, please contact one of the following:
current
C2
INPUTS
IRED anode
IRED cathode
V
Ground
SD
TXD
RXD
limiting
CC
Infrared Transceiver, 9.6 kbit/s to 115.2 kbit/s (SIR)
OPTICAL INPUT IRRADIANCE mW/m
19286
resistor
< max. irradiance E
> max. irradiance E
> min. irradiance E
CC2
and
< 4
x
x
x
is
e
e
e
depend on the quality of the supply voltages V
injected noise. An unstable power supply with dropping
voltage 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.
When connecting the described circuit to the power supply,
low impedance wiring should be used.
In case of extended wiring the inductance of the power
supply can cause dynamically a voltage drop at V
some power supplies are not able to follow the fast current is
rise time. In that case another 10 µF cap at V
helpful.
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 termination. See e.g. “The Art of
Electronics” Paul Horowitz, Wienfield Hill, 1989, Cambridge
University Press, ISBN: 0521370957.
TABLE 2 - RECOMMENDED APPLICATION
CIRCUIT COMPONENTS
TABLE 3 - RECOMMENDED RESISTOR R1 (Ω)
COMPONENT
C1, C2
R1
R2
2
V
[e-mail]
(V)
2.7
3.3
CC2
3
Tri-state floating with a weak
pull-up to the supply voltage
Low (echo on)
Low (active)
RXD
High
High
IrDA LOW POWER COMPLIANT
0.1 µF, Ceramic Vishay part#
x
47 Ω, 0.125 W (V
RECOMMENDED VALUE
VJ 1206 Y 104 J XXMT
MINIMIZED CURRENT
OUTPUTS
CONSUMPTION,
See table 3
Document Number: 84672
24
30
36
CC1
Rev. 1.5,16-Sep-09
TRANSMITTER
= 3 V)
CC2
CC2
I
0
0
0
0
0
e
CCx
. Often
will be
and