MAX13080E Datasheet, PDF (16/24 Pages) Maxim Integrated Products – +5.0V, 15kV ESD-Protected, Fail-Safe, Hot-Swap, RS-485/RS-422 Transceivers

+5.0V, ±15kV ESD-Protected, Fail-Safe,
Hot-Swap, RS-485/RS-422 Transceivers
V_CC
TIMER
TIMER
10µs
SR LATCH
5kΩ
DE
100µA
500µA
M1
M2
DE
(HOT SWAP)
Figure 9. Simplified Structure of the Driver Enable Pin (DE)
MAX13089E Programming
The MAX13089E has several programmable operating
modes. Transmitter rise and fall times are programma-
ble, resulting in maximum data rates of 250kbps,
500kbps, and 16Mbps. To select the desired data rate,
drive SRL to one of three possible states by using a
three-state driver: V_CC, GND, or unconnected. For
250kbps operation, set the three-state device in high-
impedance mode or leave SRL unconnected. For
500kbps operation, drive SRL high or connect it to V_CC.
For 16Mbps operation, drive SRL low or connect it to
GND. SRL can be changed during operation without
interrupting data communications.
Occasionally, twisted-pair lines are connected backward
from normal orientation. The MAX13089E has two pins
that invert the phase of the driver and the receiver to cor-
rect this problem. For normal operation, drive TXP and
RXP low, connect them to ground, or leave them uncon-
nected (internal pulldown). To invert the driver phase,
drive TXP high or connect it to V_CC. To invert the receiver
phase, drive RXP high or connect it to V_CC. Note that the
receiver threshold is positive when RXP is high.
The MAX13089E can operate in full- or half-duplex
mode. Drive H/F low, leave it unconnected (internal
pulldown), or connect it to GND for full-duplex opera-
tion. Drive H/F high for half-duplex operation. In full-
duplex mode, the pin configuration of the driver and
receiver is the same as that of a MAX13080E. In half-
duplex mode, the receiver inputs are internally connect-
ed to the driver outputs through a resistor-divider. This
effectively changes the function of the device’s outputs.
Y becomes the noninverting driver output and receiver
input, Z becomes the inverting driver output and receiver
input. In half-duplex mode, A and B are still connected to
ground through an internal resistor-divider but they are
not internally connected to the receiver.
±15kV ESD Protection
As with all Maxim devices, ESD-protection structures
are incorporated on all pins to protect against electro-
static discharges encountered during handling and
assembly. The driver outputs and receiver inputs of the
MAX13080E family of devices have extra protection
against static electricity. Maxim’s engineers have devel-
oped state-of-the-art structures to protect these pins
against ESD of ±15kV without damage. The ESD struc-
tures withstand high ESD in all states: normal operation,
shutdown, and powered down. After an ESD event, the
MAX13080E–MAX13089E keep working without latchup
or damage.
ESD protection can be tested in various ways. The
transmitter outputs and receiver inputs of the
MAX13080E–MAX13089E are characterized for protec-
tion to the following limits:
• ±15kV using the Human Body Model
• ±6kV using the Contact Discharge method specified
in IEC 61000-4-2
ESD Test Conditions
ESD performance depends on a variety of conditions.
Contact Maxim for a reliability report that documents
test setup, test methodology, and test results.
Human Body Model
Figure 10a shows the Human Body Model, and Figure
10b shows the current waveform it generates when dis-
charged into a low impedance. This model consists of a
100pF capacitor charged to the ESD voltage of interest,
which is then discharged into the test device through a
1.5kΩ resistor.
IEC 61000-4-2
The IEC 61000-4-2 standard covers ESD testing and
performance of finished equipment. However, it does
not specifically refer to integrated circuits. The
MAX13080E family of devices helps you design equip-
ment to meet IEC 61000-4-2, without the need for addi-
tional ESD-protection components.
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