TFDU7100-TR3 VISHAY [Vishay Siliconix], TFDU7100-TR3 Datasheet - Page 8

• Manufacturer Part Number: TFDU7100-TR3
• Description: Infrared Transceiver Module (FIR, 4 Mbit/s) for IrDA combined with Remote Control Receiver (36 kHz to 38 kHz Carrier)
• Manufacturer: VISHAY [Vishay Siliconix]

TFDU7100
Vishay Semiconductors
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.
Mode Switching
The TFDU7100 is in the SIR mode after power on as
a default mode, therefore the FIR data transfer rate
has to be set by a programming sequence using the
TXD and SD inputs as described below. The low fre-
quency mode covers speeds up to 115.2 kbit/s. Sig-
nals with higher data rates should be detected in the
high frequency mode. Lower frequency data can also
be received in the high frequency mode but with
reduced sensitivity.
To switch the transceivers from low frequency mode
to the high frequency mode and vice versa, the pro-
gramming sequences described below are required.
The SD-pulse duration for programming should be
limited to a maximum of 5 µs avoiding that the trans-
ceiver goes into sleep mode.
Setting to the High Bandwidth Mode
(0.576 Mbit/s to 4.0 Mbit/s)
1. Set SD input to logic "HIGH".
2. Set TXD input to logic "HIGH". Wait t
3. Set SD to logic "LOW" (this negative edge latches
state of TXD, which determines speed setting).
4. After waiting t
"LOW". The hold time of TXD is limited by the maxi-
mum allowed pulse length.
Table 2.
Truth table
www.vishay.com
8
high
low
low
low
low
low
SD
x
> 100 µs
TXD
high
high
low
low
low
low
x
h
> 200 ns TXD can be set to logic
> minimum irradiance in angular
< maximum irradiance in angular
> maximum irradiance in angular
Optical input Irradiance mW/m
Inputs
> specified RC sensitivity (RC-
range (IrDA)
range (IrDA)
range (IrDA)
protocol)
< 4
x
x
x
s
> 200 ns.
2
(500 kΩ to V
active low (echo)
weakly pulled
low (active)
After that TXD is enabled as normal TXD input and
the transceiver is set for the high bandwidth (576 kbit/
s to 4 Mbit/s) mode.
Setting to the Lower Bandwidth Mode
(2.4 kbit/s to 115.2 kbit/s)
1. Set SD input to logic "HIGH".
2. Set TXD input to logic "LOW". Wait t
3. Set SD to logic "LOW" (this negative edge latches
state of TXD, which determines speed setting).
4. TXD must be held for t
After that TXD is enabled as normal TXD input and
the transceiver is set for the lower bandwidth (9.6 kbit/s
to 115.2 kbit/s) mode.
RXD
high
high
x
x
SD
TXD
CC1
Figure 3. Mode Switching Timing Diagram
)
Outputs
50 %
Transmitter
t
I
0
0
0
0
0
0
s
e
h
> 200 ns.
50 %
t
h
Document Number 84773
active low (envelope)
50 %
Rev. 1.1, 27-Sep-06
s
Hig h : F IR
Low : SIR
RC-RXD
Remark
> 200 ns.
x
x
x
x
x
x
14873