LTC1320 View Datasheet(PDF) - Linear Technology
Part Name
Description
Manufacturer
LTC1320 Datasheet PDF : 8 Pages
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LTC1320
APPLICATI S I FOR ATIO
Thermal Shutdown Protection
The LTC1320 includes a thermal shutdown circuit which
protects the part against prolonged shorts at the driver
outputs. If any driver output is shorted to another output
or to the power supply, the current will be initially limited
to 450mA max. The die temperature will rise to about
150°C, at which point the thermal shutdown circuit turns
off the driver outputs. When the die cools to about 130°C,
the outputs re-enable. If the shorted condition still exists,
the part will heat again and the cycle will repeat. When the
short is removed, the part will return to normal operation.
This oscillation occurs at about 10Hz and prevents the part
from being damaged by excessive power dissipation.
Power Shutdown
The power shutdown feature of the LTC1320 is designed
primarily for battery-powered systems. When SD (pin 4)
is forced high, the part enters shutdown mode. In shut-
down, the supply current drops from 1.2mA to 30µA typ.
The driver outputs are three-stated and the power to the
receivers is removed. The receiver outputs are not auto-
matically three-stated in shutdown, and can toggle errone-
ously due to feedthrough from the inputs. This can be
prevented by pulling RXEN high along with SD; this will
three-state the receiver outputs and prevent the genera-
tion of spurious data.
Supply Bypassing
The LTC1320 requires that both VDD and VSS are well
bypassed; data errors can result from inadequate bypass-
ing. Bypass capacitor values of 0.1µF to 1µF from VDD to
ground and from VSS to ground are adequate. Lead lengths
and trace lengths between the capacitors and the chip
should be short to minimize lead inductance.
TYPICAL APPLICATI S
Single 5V Supply
5V
0.1µF
18
1
17
2
16
3
15
4
13 DRIVER I/O
LOGIC I/O 5 LTC1320 12
6
11
5V
7
10
+
8
2µF
9
8
+
2
10µF 4
LTC1046
LT1054
*
5
0.1µF
3
14
100µF
1N5817
*LTC1046 GIVES 300µA QUIESCENT
CURRENT WHEN LTC1320 IS SHUT DOWN
LT1054 PROVIDES HIGHER OUTPUT DRIVE
LTC1320 • TA03
RS422 to RS562/RS562 to RS422 Converter
5V
+
RS422 IN –
RS562 IN
0.1µF
18
VDD
11 RXD–
10 RXD+
TXO 15
RXO 6
8 RXDO
RXI 13
2 TXI
TXD+ 16
12 RXI LTC1320 TXD– 17
7 RXO
TXDEN 3
1 TXD
SD 4
RXEN 5
GND
VSS
9
14
RS562 OUT
NC
NC
+
– RS422 OUT
–5V
0.1µF
LTC1320 • TA04
6
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