MAX3535E Datasheet, PDF (1/25 Pages) Maxim Integrated Products – +3V to +5V, 2500VRMS Isolated RS-485/RS-422 Transceivers with ±15kV ESD Protection

19-3270; Rev 0; 4/04
+3V to +5V, 2500V_RMS Isolated RS-485/RS-422
Transceivers with ±15kV ESD Protection
General Description
The MAX3535E/MXL1535E isolated RS-485/RS-422 full-
duplex transceivers provide 2500V_RMS of galvanic isola-
tion between the RS-485/RS-422 side and the processor
or control logic side. These devices allow fast,
1000kbps communication across an isolation barrier
when the common-mode voltages (i.e., the ground
potentials) on either side of the barrier are subject to
large differences. Isolation is achieved through integrat-
ed high-voltage capacitors. The MAX3535E/MXL1535E
also feature a 420kHz transformer driver that allows
power transfer to the RS-485 side using an external
transformer.
The MAX3535E/MXL1535E include one differential driver,
one receiver, and internal circuitry to send the RS-485
signals and control signals across the isolation barrier
(including the isolation capacitors). The MAX3535E/
MXL1535E RS-485 receivers are 1/8 unit load, allowing
up to 256 devices on the same bus.
The MAX3535E/MXL1535E feature true fail-safe circuitry.
The driver outputs and the receiver inputs are protected
from ±15kV electrostatic discharge (ESD) on the inter-
face side, as specified in the Human Body Model (HBM).
The MAX3535E/MXL1535E feature driver slew-rate
select that minimizes electromagnetic interference (EMI)
and reduces reflections. The driver outputs are short-cir-
cuit and overvoltage protected. Other features are hot-
swap capability and isolation-barrier fault detection.
The MAX3535E operates with a single +3V to +5.5V
power supply. The improved secondary supply range of
the MAX3535E allows the use of step-down transformers
for +5V operation, resulting in considerable power sav-
ings. The MXL1535E operates with a single +4.5V to
+5.5V power supply. The MXL1535E is a function-/pin-
compatible improvement of the LTC1535. The
MAX3535E/MXL1535E are available over the commer-
cial 0°C to +70°C and extended -40°C to +85°C temper-
ature ranges.
Applications
Isolated RS-485 Systems
Systems with Large Common-Mode Voltages
Industrial-Control Local Area Networks
Telecommunications Systems
Typical Application Circuit appears at end of data sheet.
Features
♦ 2500V_RMS RS-485 Bus Isolation Using On-Chip
High-Voltage Capacitors
♦ 1000kbps Full-Duplex RS-485/RS-422
Communication
♦ +3V to +5.5V Power-Supply Voltage Range
(MAX3535E)
♦ +4.5V to +5.5V Power-Supply Voltage Range
(MXL1535E)
♦ 1/8 Unit Receiver Load, Allowing 256 Devices on
Bus
♦ ±15kV ESD Protection Using HBM
♦ Pin-Selectable Slew-Rate Limiting Controls EMI
♦ Hot-Swap-Protected Driver-Enable Input
♦ Undervoltage Lockout
♦ Isolation-Barrier Fault Detection
♦ Short-Circuit Protected
♦ Thermal Shutdown
♦ Open-Line and Shorted-Line Fail-Safe Receiver
Inputs
Ordering Information
PART
TEMP RANGE
PIN-
PACKAGE
MAX3535ECWI 0°C to +70°C
MAX3535EEWI -40°C to +85°C
MXL1535ECWI 0°C to +70°C
MXL1535EEWI -40°C to +85°C
28 Wide SO
28 Wide SO
28 Wide SO
28 Wide SO
POWER-
SUPPLY
RANGE
(V)
+3.0 to +5.5
+3.0 to +5.5
+4.5 to +5.5
+4.5 to +5.5
TOP VIEW
Pin Configuration
VCC1 1
ST1 2
ST2 3
GND1 4
28 RO1
27 RE
26 DE
25 DI
MAX3535E
MXL1535E
GND2 11
18 SLO
Z 12
17 RO2
Y 13
16 A
VCC2 14
15 B
WIDE SO
PINS 5–10 and 19–24 ARE REMOVED FROM THE PACKAGE
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