Datasheet
±
SLLS349J − JUNE 1999 − REVISED MARCH 2004
2
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
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
approximately 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 occurs 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 activates automatically when 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
OUTPUT
DIN FORCEON
FORCEOFF
TIME ELAPSED SINCE LAST
RIN OR DIN TRANSITION
OUTPUT
DOUT
DRIVER STATUS
X X L X Z Powered off
L H H X H
Normal operation with
H HH X L
Normal operation with
auto-powerdown plus disabled
L L H <30 s H
Normal operation with
H L H <30 s L
Normal operation with
auto-powerdown plus enabled
L L H >30 s Z
Powered off by
H L H >30 s Z
Powered off by
auto-powerdown plus feature
H = high level, L = low level, X = irrelevant, Z = high impedance
EACH RECEIVER
INPUTS
OUTPUTS
RIN1 RIN2−RIN3
FORCEOFF
TIME ELAPSED SINCE LAST RIN
OR DIN TRANSITION
ROUT1B ROUT
RECEIVER STATUS
L X L X L Z
Powered off while
H XL X H Z
Powered off while
ROUT1B is active
L L H <30 s L H
L H H <30 s L L
Normal operation with
H L H <30 s H H
Normal operation with
auto-powerdown plus
disabled/enabled
H H H <30 s H L
auto-powerdown plus
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