
6
LTC1387
FU CTIO TABLES
UU
Select Modes
SELECT INPUTS
RECEIVER
DRIVER
ON
RXEN DXEN
485/232
RXA
RXB
DXY
DXZ
1
0
Z
ON
OFF
RS232 Mode, DX and RX Off
1
0
1
0
Z
ON
OFF
RS232 Mode, DXY and DXZ On, RX Off
1
0
ON
Z
ON
OFF
RS232 Mode, DX Off, RXA and RXB On
1
0
ON
OFF
RS232 Mode, DXY and DXZ On,
RXA and RXB On
0
1
0
Z
ON
Z
ON
OFF
RS232 Mode, DXY On, DXZ Off, RX Off
0
1
0
Z
ON
Z
ON
OFF
RS232 Mode, DXY On,
DXZ Off, RXA Off, RXB On
0
1
0
ON
RS232 Loopback Mode, DXY and DXZ On,
RXA and RXB On
0
X
Z
OFF
Shutdown, RS485 RIN
1
0
1
Z
ON
OFF
RS485 Mode, DX and RX Off
X
0
1
Z
ON
OFF
RS485 Mode, DX On, RX Off
X
1
0
1
ON
Z
ON
OFF
RS485 Mode, DX Off, RX On
1
ON
Z
ON
OFF
RS485 Mode, DX On, RX On
0
1
ON
Z
ON
RS485 Loopback Mode, DX On, RX On
RS232 Driver Mode
INPUTS
OUTPUTS
SELECTED
485/232
D
CONDITIONS
Y, Z
YES
0
No Fault
1
YES
0
1
No Fault
0
YES
0
X
Thermal Fault
Z
NO
0
X
Z
RS232 Receiver Mode
INPUTS
OUTPUTS
SELECTED
485/232
A, B
RA, RB
YES
0
1
YES
0
1
0
YES
0
Inputs Open
1
NO
0
X
Z
RS485 Driver Slew Rate
INPUTS
OUTPUTS
DXEN
485/232
SLEW
SLEW RATE
1
0
Slow
1
Fast
01
X
Z
RS485 Driver Mode
INPUTS
OUTPUTS
DXEN
485/232
D
CONDITIONS
Z
Y
1
0
No Fault
0
1
No Fault
1
0
1
X
Thermal Fault
Z
01
X
Z
RS485 Receiver Mode
INPUTS
OUTPUTS
RXEN
485/232
B – A
RA
RB
1
< – 0.2V
0
Z
1
> 0.2V
1
Z
1
Inputs Open
1
Z
or Shorted to Ground
01
X
Z
CHARGE PUMP LOOPBACK
COMMENTS