Datasheet

3
LTC1387
DC ELECTRICAL CHARACTERISTICS
T
A
= 25°C, V
CC
= 5V, C1 = C2 = C3 = C4 = 0.1µF (Notes 2, 3), unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
RS485 Receiver (485/232 = High, ON = RXEN = High)
V
TH
Differential Input Threshold Voltage –7V ≤ V
CM
≤ 12V ● –0.20 0.20 V
∆V
TH
Input Hysteresis V
CM
= 0V 40 mV
I
IN
Input Current (A, B) V
IN
= 12V ● 1mA
V
IN
= –7V ● –0.8 mA
R
IN
Input Resistance –7V ≤ V
IN
≤ 12V ● 12 24 kΩ
RS232 Receiver (485/232 = Low, ON = RXEN = High)
V
TH
Receiver Input Voltage Threshold Input Low Threshold ● 0.8 V
Input High Threshold
● 2.4 V
∆V
TH
Receiver Input Hysteresis 0.6 V
R
IN
Receiver Input Resistance V
IN
= ±10V 3 5 7 kΩ
Receiver Output (ON = RXEN = High)
V
OH
Receiver Output High Voltage I
O
= –3mA, V
IN
= 0V, 485/232 = Low ● 3.5 4.6 V
V
OL
Receiver Output Low Voltage I
O
= 3mA, V
IN
= 3V, 485/232 = Low ● 0.2 0.4 V
I
OSR
Short-Circuit Current 0V ≤ V
O
≤ V
CC
● 785mA
I
OZR
Three-State Output Current RXEN = 0V ● ±0.1 ±10 µA
Power Supply Generator
V
DD
V
DD
Output Voltage No Load, ON = DXEN = RXEN = High 8 V
I
DD
= –5mA, ON = DXEN = RXEN = High 7 V
V
EE
V
EE
Output Voltage No Load, ON = DXEN = RXEN = High –7.7 V
I
EE
= 5mA, ON = DXEN = RXEN = High –7.0 V
Power Supply
I
CC
V
CC
Supply Current No Load, ON = DXEN = RXEN = High ● 725 mA
Shutdown, ON = DXEN = RXEN = 0V
● 5 100 µA
AC ELECTRICAL CHARACTERISTICS
T
A
= 25°C, V
CC
= 5V, C1 = C2 = C3 = C4 = 0.1µF (Notes 2, 3), unless otherwise noted.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
RS232 Mode (ON = DXEN = RXEN = High, 485/232 = Low)
SR Slew Rate Figure 4, R
L
= 3k, C
L
= 15pF ● 30 V/µs
Figure 4, R
L
= 3k, C
L
= 1000pF ● 4V/µs
t
T
Transition Time Figure 4, R
L
= 3k, C
L
= 2500pF ● 0.22 1.9 3.1 µs
t
PLH
Driver Input to Output Figures 4, 10, R
L
= 3k, C
L
= 15pF ● 0.6 4 µs
t
PHL
Driver Input to Output Figures 4, 10, R
L
= 3k, C
L
= 15pF ● 0.6 4 µs
t
PLH
Receiver Input to Output Figures 5, 11 ● 0.3 6 µs
t
PHL
Receiver Input to Output Figures 5, 11 ● 0.4 6 µs
RS485 Mode (Fast Slew Rate, ON = DXEN = High, 485/232 = High, SLEW = High)
t
PLH
Driver Input to Output Figures 2, 7, R
L
= 54Ω, C
L
= 100pF ● 15 40 70 ns
t
PHL
Driver Input to Output Figures 2, 7, R
L
= 54Ω, C
L
= 100pF ● 15 40 70 ns
t
SKEW
Driver Output to Output Figures 2, 7, R
L
= 54Ω, C
L
= 100pF ● 515 ns
t
r
, t
f
Driver Rise or Fall Time Figures 2, 7, R
L
= 54Ω, C
L
= 100pF ● 31540 ns