MAX3362EKATG16 Maxim Integrated Products, Inc., MAX3362EKATG16 Datasheet - Page 12

• Manufacturer Part Number: MAX3362EKATG16
• Description: Max3362 3.3v, High-speed, Rs-485/rs-422 Transceiver In Sot Package
• Manufacturer: Maxim Integrated Products, Inc.

3.3V, High-Speed, RS-485/RS-422 Transceiver in
SOT Package
Figure 11. Differential Power-Up Glitch (1V/µs)
connected to the line and is powered up the driver
must not cause the differential signal to drop below
200mV. Figures 10, 11, and 12 show the results of the
MAX3362 during power-up for three different V
rates (0.1V/µs, 1V/µs, and 10V/µs). The photos show
the V
the 100Ω termination, as well as the differential signal
across the termination.
Low-power shutdown mode is initiated by bringing both
RE high and DE low. In shutdown, the MAX3362 typi-
cally draws only 1µA supply current.
RE and DE may be driven simultaneously; the device is
guaranteed not to enter shutdown if RE is high and DE
is low for less than 50ns. If the inputs are in this state
for at least 600ns, the device will enter shutdown.
Enable times t
Switching Characteristics table assume the device was
not in a low-power shutdown state. Enable times t
t
down. Drivers and receivers take longer to become
enabled from low-power shutdown mode than from
driver/receiver disable mode.
Figures 5 and 6 show the typical propagation delays.
Skew time is simply the difference between the low-to-
high and high-to-low propagation delay. Small
driver/receiver skew times help maintain a symmetrical
mark-space ratio (50% duty cycle). Both the receiver
skew time and driver skew time are under 6ns.
12
PDSL,
______________________________________________________________________________________
CC
t
PRSH,
V
A-B
ramp, the single-ended signal on each side of
CC
A
B
and t
Applications Information
PDZH,
Low-Power Shutdown Mode
PRSL
t
PDZL,
1µs/div
assume the device was shut
t
Propagation Delays
PRZH
and t
3.3V
0
10mV/div
AC-COUPLED
10mV/div
AC-COUPLED
10mV/div
PRZL
CC
in the
PDSH,
ramp
The standard RS-485 receiver input impedance is 12kΩ
(one-unit load), and a standard driver can drive up to
32 unit loads. The MAX3362 transceiver has a 1/8-unit-
load receiver input impedance (96kΩ), allowing up to
256 transceivers to be connected in parallel on one
communication line. Any combination of these devices
and/or other RS-485 transceivers with a total of 32 unit
loads or less can be connected to the line.
Two mechanisms prevent excessive output current and
power dissipation caused by faults or by bus con-
tention. The first, a foldback current limit on the output
stage, provides immediate protection against short cir-
cuits over the whole common-mode voltage range (see
Typical Operating Characteristics). The second, a ther-
mal shutdown circuit, forces the driver outputs into a
high-impedance state if the die temperature becomes
excessive.
The MAX3362 transceiver is designed for bidirectional
data communications on multipoint bus transmission
lines. The Typical Operating Circuit shows a typical net-
work applications circuit. To minimize reflections, the
line should be terminated at both ends in its character-
istic impedance, and stub lengths off the main line
should be kept as short as possible.
Figure 12. Differential Power-Up Glitch (10V/µs)
V
A-B
CC
A
B
256 Transceivers on the Bus
200ns/div
Driver Output Protection
Typical Applications
3.3V
0
50mV/div
AC-COUPLED
50mV/div
AC-COUPLED
10mV/div