lt1328 Linear Technology Corporation, lt1328 Datasheet - Page 7

• Manufacturer Part Number: lt1328
• Description: 4mbps Irda Infrared Receiver
• Manufacturer: Linear Technology Corporation

APPLICATIONS
In situations where long range is not a requirement, a very
simple IR link can be made using unmodulated NRZ
(nonreturn to zero) data. The circuit is shown in Figure 5.
A BER (bit-error rate) transmitter and receiver was used to
test the data-link error rates for data rates of 375kbps.
Because the NRZ data can have long stretches of continu-
ous “1” data, the low frequency corner of the LT1328
photodiode receiver is set to 14Hz to prevent pulse-top
distortion.
U
INFORMATION
R2
10k
U
375bps NRZ DATA
C5
4.7 F
100
R1
W
5V
R3
3.9
1/2W
Q3
2N7002
D2
HSDL 4220
TRANSMITTER/RECEIVER
BIT ERROR RATE
OUT
Figure 5. Simple NRZ Data Link
U
BPV22NF
24"
TEMIC
IN
D1
To do this, make C1 4.7 F. This is the only change from
a standard IrDA-SIR receiver. A range of 24" (with a bit
error rate lower than 1 in 10
additional processing beyond that provided by the LT1328.
A caution: when using unmodulated data, it is possible to
get a 100% duty cycle on the LED transmitter, so be sure
that the LED can handle this.
C4
4.7 F
NC
1
2
3
4
LT1328
8
7
6
5
1328 F05
8
) is achieved with no
C6
1000pF
C2
4.7 F
5V
LT1328
7