Datasheet

LTC2870/LTC2871
5
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For more information www.linear.com/LTC2870
elecTrical characTerisTics
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= V
L
= 3.3V, TE485 = 0V, LB = 0V unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
R
TERM
Terminating Resistor TE485 = V
L
, A – B = 2V, B = –7V, 0V, 10V
(Figure8) (Note 5)
l
108 120 156 Ω
RS232 Driver
V
OLD
Output Low Voltage R
L
= 3kΩ; V
EE
≤ –5.9V
l
–5 –5.7 –7.5 V
V
OHD
Output High Voltage R
L
= 3kΩ; V
DD
≥ 6.5V
l
5 6.2 7.5 V
Three-State (High Impedance) Output Current Y or Z (LTC2870) = ±15V
RS232 Receiver Enabled
DOUT1 or DOUT2 (LTC2871) = ±15V
l
l
±156
±10
µA
µA
Output Short-Circuit Current Driver Output = 0V
l
±35 ±90 mA
RS232 Receiver
Input Threshold Voltage
l
0.6 1.5 2.5 V
Input Hysteresis
l
0.1 0.4 1.0 V
Output Low Voltage I(RA, RB, ROUT1, ROUT2) = 1mA (Sinking)
1.7V ≤ V
L
≤ 5.5V
l
0.4 V
Output High Voltage I(RA, RB, ROUT1, ROUT2) = –1mA (Sourcing)
1.7V ≤ V
L
≤ 5.5V
l
V
L
– 0.4 V
Input Resistance –15V ≤ (A, B, RIN1, RIN2) ≤ 15V,
RS232 Receiver Enabled
l
3 5 7 kΩ
Three-State (High Impedance) Output Current 0V ≤ (RA, RB, ROUT1, ROUT2) ≤ V
L
l
0 ±5 µA
Output Short-Circuit Current V
L
= 5.5V
0V ≤ (RA, RB, ROUT1, ROUT2) ≤ V
L
l
±25 ±50 mA
Logic Inputs
Threshold Voltage
l
0.4 0.75 • V
L
V
Input Current
l
0 ±5 µA
Power Supply Generator
V
DD
Regulated V
DD
Output Voltage RS232 Drivers Enabled, Outputs Loaded with
R
L
= 3kΩ to GND, DIN1/DY = V
L
, DIN2/DZ = 0V
(Note 3)
7 V
V
EE
Regulated V
EE
Output Voltage –6.3 V
ESD
LTC2870 Interface Pins (A, B, Y, Z) Human Body Model to GND or V
CC
, Powered or
Unpowered (Note 7)
±26 kV
LTC2871 Interface Pins (A, B, Y, Z, RIN1,
RIN2, DOUT1, DOUT2)
±16 kV
All Other Pins Human Body Model (Note 7) ±4 kV
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