LTC1387 Linear Technology, LTC1387 Datasheet - Page 4

• Manufacturer Part Number: LTC1387
• Description: Single 5V RS232/RS485 Multiprotocol Transceiver
• Manufacturer: Linear Technology

AC ELECTRICAL CHARACTERISTICS
LTC1387
T
SYMBOL
RS485 Mode (Fast Slew Rate, ON = DXEN = High, 485/232 = High, SLEW = High)
t
t
t
t
RS485 Mode (Slow Slew Rate, ON = DXEN = High, 485/232 = High, SLEW = Low)
t
t
t
t
t
t
t
t
RS485 Mode (ON = RXEN = High, 485/232 = High)
t
t
t
Receiver Output Enable/Disable (ON = High)
t
t
t
t
The
temperature range.
Note 1: Absolute Maximum Ratings are those values beyond which the life
of the device may be impaired.
Note 2: All currents into device pins are positive; all currents out of device
pins are negative. All voltages are referenced to device ground unless
otherwise specified.
C1
Requires an external 0.1 F capacitor between Pins 1 and 2.
C1
V
Requires an external 0.1 F capacitor to ground.
A (Pin 4): Receiver Input A. Inverting input of RS232
receiver A in RS232 mode; inverting RS485 receiver input
in RS485 mode.
4
PIN
ZL
ZH
LZ
HZ
SKEW
r
ZL
ZH
LZ
HZ
SKEW
ZL
ZH
LZ
HZ
PLH
PHL
PLH
PHL
A
, t
DD
= 25 C, V
f
+
–
U
(Pin 1): Commutating Capacitor C1 Positive Terminal.
(Pin 2): Commutating Capacitor C1 Negative Terminal.
denotes specifications which apply over the full operating
(Pin 3): Charge Pump Positive Supply Output.
FUNCTIONS
PARAMETER
Driver Enable to Output Low
Driver Enable to Output High
Driver Disable from Low
Driver Disable from High
Driver Input to Output
Driver Input to Output
Driver Output to Output
Driver Rise or Fall Time
Driver Enable to Output Low
Driver Enable to Output High
Driver Disable from Low
Driver Disable from High
Receiver Input to Output
Receiver Input to Output
Differential Receiver Skew, t
Receiver Enable to Output Low
Receiver Enable to Output High
Receiver Disable from Low
Receiver Disable from High
CC
U
= 5V, C1 = C2 = C3 = C4 = 0.1 F (Notes 2, 3), unless otherwise noted.
U
PLH
– t
PHL
CONDITIONS
Figures 3, 8, C
Figures 3, 8, C
Figures 3, 8, C
Figures 3, 8, C
Figures 2, 7, R
Figures 2, 7, R
Figures 2, 7, R
Figures 2, 7, R
Figures 3, 8, C
Figures 3, 8, C
Figures 3, 8, C
Figures 3, 8, C
Figures 2, 9, R
Figures 2, 9, R
Figures 2, 9, R
Figures 6, 12, C
Figures 6, 12, C
Figures 6, 12, C
Figures 6, 12, C
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
= 100pF, S1 Closed
= 100pF, S2 Closed
= 15pF, S1 Closed
= 15pF, S2 Closed
= 100pF, S1 Closed
= 100pF, S2 Closed
= 15pF, S1 Closed
= 15pF, S2 Closed
Note 3: All typicals are given at V
and T
Note 4: Short-circuit current for RS485 driver output low state folds back
above V
Note 5: SLEW includes an internal pull-up in RS485 mode.
B (Pin 5): Receiver Input B. Inverting input of RS232
receiver B in RS232 mode; noninverting RS485 receiver
input in RS485 mode.
Y (Pin 6): Driver Output Y. Inverting RS232 driver Y output
in RS232 mode; inverting RS485 driver output in RS485
mode.
Z (Pin 7): Driver Output Z. Inverting RS232 driver Z output
in RS232 mode; noninverting RS485 driver output in
RS485 mode.
= 54 , C
= 54 , C
= 54 , C
= 54 , C
= 54 , C
= 54 , C
= 54 , C
= 15pF, S1 Closed
= 15pF, S2 Closed
= 15pF, S1 Closed
= 15pF, S2 Closed
A
= 25 C.
CC
L
L
L
L
L
L
L
. Peak current occurs around V
= 100pF
= 100pF
= 100pF
= 100pF
= 100pF
= 100pF
= 100pF
CC
= 5V, C1 = C2 = C3 = C4 = 0.1 F
MIN
100
100
150
20
20
O
= 3V.
TYP
700
700
200
300
600
600
100
100
50
50
50
60
70
70
10
40
40
40
40
1500
1500
1500
1500
1500
MAX
750
200
200
140
140
90
90
90
90
90
90
90
90
UNITS
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns