ISL32173E Datasheet, PDF (14/22 Pages) Intersil Corporation – QUAD, ±16.5kV ESD Protected, 3.0V to 5.5V, RS-485/RS-422 Receivers

ISL32173E, ISL32175E, ISL32177E, ISL32273E, ISL32275E, ISL32277E
both ends. Stubs connecting a transmitter or receiver to
the main cable should be kept as short as possible.
Low Power Shutdown Mode
These BiCMOS receivers all use a fraction of the power
required by their bipolar counterparts, but they also
include a shutdown (SHDN) feature that reduces the
already low quiescent ICC to a microamp trickle. These
devices enter shutdown only when all four receivers
disable (see “Truth Tables” on page 4) for at least 600ns.
The ISL32X73E types enter SHDN whenever EN is low
and EN is high. ISL32X75E types enter SHDN only if both
EN12 and EN34 are low. Note that the ISL32X75E enable
times increase significantly when enabling from the
SHDN condition.
The ISL32X77E enter the low power SHDN mode if
SHDNEN is high, and if all four Rx are disabled for at
least 600ns. This is accomplished by driving EN low and
EN high, or by driving all four ENX inputs low. Enable
times increase if the IC was in SHDN, so if enable time is
more important than SHDN supply current, tying the
SHDNEN pin low defeats the low power SHDN feature. In
this mode, the supply current drops to 1mA to 2mA when
all four Rx are disabled, but the enable time of any Rx
remains below 200ns.
Remember that all enable pins have pull-up resistors on
them, so each pin that is low during SHDN adds up to
15μA to the SHDN supply current. The SHDN supply
current entries in the “Electrical Specifications” table on
page 9 include the resistor currents of the pins indicated
to be in the low state.
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FN7529.0
November 19, 2009