LT1328CMS8 Linear Technology, LT1328CMS8 Datasheet - Page 4

• Manufacturer Part Number: LT1328CMS8
• Description: IC RECEIVER 4MBPS IRDA IR 8-MSOP
• Manufacturer: Linear Technology
• Type: Receiverr

Specifications of LT1328CMS8

• Number Of Drivers/receivers: 0/1
• Protocol: Infrared (IRDA)
• Voltage - Supply: 4.5 V ~ 5.5 V
• Mounting Type: Surface Mount
• Package / Case: 8-MSOP, Micro8™, 8-uMAX, 8-uSOP,
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

PIN
BLOCK
LT1328
IN (Pin 1): Connect this pin to the photodiode cathode.
This is the input to the preamplifier and is held at 1.5V by
the output of the DC servo. To maintain the 1.5V on this
pin, the DC servo can source up to 2mA or sink 40 A to this
pin.
FILTER (Pin 2): Connect a capacitor from this pin to
ground. The value of the capacitor will set the band of
frequencies that will be attenuated by the servo. The pole
is set by the formula f = 25/(2 • 60k • C). A 330pF
capacitor will attenuate photodiode signals below 200kHz
when operating at high data rates (FIR and 4ppm).
FILTER SWITCH (Pin 3): Collector of a Transistor Switch.
When the MODE switch (Pin 7) is TTL HIGH this pin will be
switched to ground. This pin is used to increase the filter
capacitor for slower data rates (SIR). A 10nF capacitor
from Pin 2 to Pin 3 will bring the highpass frequency down
to 6.6kHz for SIR.
4
U
FUNCTIONS
U
DIAGRAM
D1
PHOTODIODE
TEMIC
BPV22NF
C4
330pF
U
C1
10nF
W
1
2
3
4
IN
FILTER
FILTER SWITCH
GND
FILTER
V
CC
R
2k
IN
Figure 1. LT1328 Block Diagram
PREAMP
DC SERVO
60k
g
R
50k
m
FB
+
–
GND (Pin 4): Ground.
DATA (Pin 5): TTL Output of the Comparator. A TTL LOW
at this pin indicates that the photodiode has received a
pulse of light. This pin will remain HIGH when the light
signal and noise are below the attenuation band of the DC
servo.
V
close as possible from Pin 6 to ground is recommended
(4.7 F).
MODE (Pin 7): A TTL HIGH on this pin will cause the open
collector at Pin 3 to switch to ground. This is an option that
switches in extra capacitance for lower frequency data
rates. If this pin is not used, select a capacitor (C4) to
accommodate the lowest data rate (for IrDA C4 = 10nF).
V
is required.
CC
BIAS
(Pin 6): 5V Supply. A bypass capacitor, connected as
(Pin 8): A 1000pF capacitor from this pin to ground
COMPARATOR
–
+
1.5V
BIAS
MODE
V
DATA
BIAS
V
CC
8
7
6
5
1328 BD
5V
C6
1000pF
C2
4.7 F
HIGH: SIR
LOW: FIR AND 4ppm