LT1081 LINER [Linear Technology], LT1081 Datasheet - Page 4

• Manufacturer Part Number: LT1081
• Description: Advanced Low Power 5V RS232 Dual Driver/Receiver
• Manufacturer: LINER [Linear Technology]

PI FU CTIO S
LT1080/LT1081
C1
capacitor ( 1 F) from C1
to C2
supply. When a separate positive supply is used, C1 can be
deleted.
V
V
for charge storage. May be loaded (up to 15mA) for
external system use. Loading does reduce V
graphs). Capacitor may be tied to ground or +5V input
supply. With multiple transceivers, the V
be paralleled into common capacitors.
V
V
( 1 F) for charge stroage. May be loaded (up to –15mA)
for external system use. Loading does reduce V
(see graphs). With multiple transceivers, the V
pins may be paralleled into common capacitors.
TR2 OUT; TR1 OUT (Pins 8, 15): Driver Outputs with
RS232 Voltage Levels. Outputs are in a high impedance
state when in the SHUTDOWN mode or when power is off
(V
short-circuit protected from (V
power on, off or in the SHUTDOWN mode. Typical output
breakdowns are greater than 45V and higher applied
TYPICAL PERFOR A CE CHARACTERISTICS
4
+
+
–
–
CC
+
–10
U
(Pin 3): Positive Supply for RS232 Drivers.
(Pin 7): Negative Supply for RS232 Drivers.
–2
–4
–6
–8
; C1
10
8
6
4
2
0
2V
–55
–
= 0V) to allow data line sharing. Outputs are fully
Driver Output Voltage
. Pin 2 can be used for connecting a second positive
–(2V
V
V
R
V
V
–
CC
CC
CC
CC
CC
L
; C2
= 3k
–25
= 5.5V
= 4.5V
= 4.5V
= 5.5V
– 1.5V. Requires an exterenal capacitor ( 1 F)
U
CC
+
; C2
0
– 2.5V). Requires an external capacitor
TEMPERATURE ( C)
V
V
–
CC
CC
25
(Pins 2, 4, 5, 6): Requires an external
= 5V
= 5V
OUTPUT HIGH
OUTPUT LOW
U
50
+
75
to C1
(Pin numbers refer to LT1080)
W
–
100
1080/81 G01
+ 30V) to (V
–
U
and another from C2
125
+
and V
+
–10
+
–2
–4
–6
–8
10
voltage (see
8
6
4
2
0
– 30V) with
–
0
Supply Generator Outputs
LOADED TO V
V
LOADED TO V
pins may
–
+
CC
voltage
2
and V
= 5V
4
OUTPUT CURRENT (mA)
6
+
–
–
+
V
V
+
–
8
OUTPUT VOLTAGE
OUTPUT VOLTAGE
voltages will not damage the device if moderately current
limited. Shorting one output will affect output from the
other.
REC2 IN; REC1 IN (Pins 9, 14): Receiver Inputs. Accepts
RS232 voltage levels ( 30V) and has 0.4V of hysteresis to
provide noise immunity. Input impedance is nominally
5k .
REC2 OUT; REC1 OUT (Pins 10, 13): Receiver Outputs
with TTL/CMOS Voltage Levels. Outputs are in a high
impedance state when in the SHUTDOWN mode to allow
data line sharing. Outputs are fully short-circuit protected
to ground or V
mode.
TR2 IN; TR1 IN (Pins 11, 12): RS232 Driver Input Pins.
Inputs are TTL/CMOS compatible. Inputs should not be
allowed to float. Tie unused inputs to V
GND (Pin 16): Ground Pin.
V
zero in the SHUTDOWN mode.
ON/OFF (Pin 18): Contols the operation mode of the
LT1080 and is TTL/CMOS compatible. A logic low puts the
device in the SHUTDOWN mode which reduces input
supply current to zero and places both driver and receiver
outputs in a high impedance state. A logic high fully
enables the device.
10 12 14 16 18 20
LOADED TO GROUND
LOADED TO GROUND
CC
(Pin 17): Input Supply Pin. Supply current drops to
1080/81 G02
CC
with power on, off or in the SHUTDOWN
–10
10
–2
–4
–6
–8
8
6
4
2
0
0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
Supply Generation from V
or Shutdown
V
V
+
–
SUPPLY
SUPPLY
TIME (ms)
CC
.
V
C1 TO C4 = 1 F
R
CC
L
= 4.7k; V
= 5V
CC
+
TO V
1080/81 G03
–