Datasheet

B
A
R
100 W
±1%
+
-
PulseGenerator
15 msduration
1%DutyCycle
t ,t 100ns
r f
£
Z
Y
D
100 W
±1%
+
-
DE
0Vor3V
0Vor3V
RE
4
5
9
10
Y
Z
D
DE
A
B
12
11
2
R
3
RE
Low-Power
Standby
SN65HVD50-SN65HVD55
SLLS666E –SEPTEMBER 2005–REVISED OCTOBER 2009 www.ti.com
PARAMETER MEASUREMENT INFORMATION (continued)
Figure 12. Test Circuit, Transient Overvoltage Test
DEVICE INFORMATION
LOW-POWER STANDBY MODE
When both the driver and receiver are disabled (DE low and RE high) the device is in standby mode. If the
enable inputs are in this state for less than 60 ns, the device does not enter standby mode. This guards against
inadvertently entering standby mode during driver/receiver enabling. Only when the enable inputs are held in this
state for 300 ns or more, the device is assured to be in standby mode. In this low-power standby mode, most
internal circuitry is powered down, and the supply current is typically less than 1 nA. When either the driver or the
receiver is re-enabled, the internal circuitry becomes active.
Figure 13. Low-Power Standby Logic Diagram
If only the driver is re-enabled (DE transitions to high) the driver outputs are driven according to the D input after
the enable times given by t
PZH2
and t
PZL2
in the driver switching characteristics. If the D input is open when the
driver is enabled, the driver outputs defaults to A high and B low, in accordance with the driver failsafe feature.
If only the receiver is re-enabled (RE transitions to low) the receiver output is driven according to the state of the
bus inputs (A and B) after the enable times given by t
PZH2
and t
PZL2
in the receiver switching characteristics. If
there is no valid state on the bus the receiver responds as described in the failsafe operation section.
If both the receiver and driver are re-enabled simultaneously, the receiver output is driven according to the state
of the bus inputs (A and B) and the driver output is driven according to the D input. Note that the state of the
active driver affects the inputs to the receiver. Therefore, the receiver outputs are valid as soon as the driver
outputs are valid.
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