SN65C3238_06 Datasheet, PDF (2/17 Pages) Texas Instruments – 3-V TO 5.5-V MULTICHANNEL RS-232 COMPATIBLE LINE DRIVER/RECEIVER

SN65C3238, SN75C3238
ą
3ĆV TO 5.5ĆV MULTICHANNEL RSĆ232 COMPATIBLE LINE DRIVER/RECEIVER
ą
SLLS352F − JUNE 1999 − REVISED OCTOBER 2004
description/ordering information (continued)
Flexible control options for power management are featured when the serial-port and driver inputs are inactive.
The auto-powerdown plus feature functions when FORCEON is low and FORCEOFF is high. During this mode
of operation, if the device does not sense valid signal transitions on all receiver and driver inputs for 30 s, the
built-in charge-pump and drivers are powered down, reducing the supply current to 1 µA. By disconnecting the
serial port or placing the peripheral drivers off, auto-powerdown plus will occur if there is no activity in the logic
levels for the driver inputs. Auto-powerdown plus can be disabled when FORCEON and FORCEOFF are high.
With auto-powerdown plus enabled, the device automatically activates once a valid signal is applied to any
receiver or driver input. INVALID is high (valid data) if any receiver input voltage is greater than 2.7 V or less
than −2.7 V or has been between −0.3 V and 0.3 V for less than 30 µs. INVALID is low (invalid data) if all receiver
input voltages are between −0.3 V and 0.3 V for more than 30 µs. Refer to Figure 5 for receiver input levels.
Function Tables
EACH DRIVER
INPUTS
DIN
FORCEON FORCEOFF
TIME ELAPSED SINCE LAST
RIN OR DIN TRANSITION
X
X
L
X
L
H
H
X
H
H
H
X
L
L
H
<30 s
H
L
H
<30 s
L
L
H
>30 s
H
L
H
>30 s
H = high level, L = low level, X = irrelevant, Z = high impedance
OUTPUT
DOUT
DRIVER STATUS
Z
Powered off
H
Normal operation with
L
auto-powerdown plus disabled
H
Normal operation with
L
auto-powerdown plus enabled
Z
Powered off by
Z
auto-powerdown plus feature
EACH RECEIVER
RIN2
RIN1,
RIN3−RIN5
INPUTS
TIME ELAPSED SINCE LAST
FORCEOFF _{RIN OR DIN TRANSITION}
OUTPUTS
ROUT1B ROUT
RECEIVER STATUS
L
X
L
H
X
L
X
L
Z
Powered off while
X
H
Z
ROUT1B is active
L
L
H
<30 s
L
H
L
H
H
H
L
H
H
H
H
<30 s
<30 s
<30 s
L
L
Normal operation with
H
H
auto-powerdown plus
H
L
disabled/enabled
Open
Open
H
>30 s
L
H
H = high level, L = low level, X = irrelevant, Z = high impedance (off), Open = input disconnected or connected driver off
2
• POST OFFICE BOX 655303 DALLAS, TEXAS 75265