MAX13485EEVKIT+ Maxim Integrated Products, MAX13485EEVKIT+ Datasheet - Page 14

• Manufacturer Part Number: MAX13485EEVKIT+
• Description: KIT FOR MAX1348 RS485/RS422 TXRX
• Manufacturer: Maxim Integrated Products

Specifications of MAX13485EEVKIT+

• Main Purpose: Interface, RS-422/RS-485 Transceiver
• Embedded: No
• Utilized Ic / Part: MAX13485E
• Primary Attributes: 1 Driver, 1 Receiver
• Secondary Attributes: Half-Duplex, ESD-Protected
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Half-Duplex RS-485/RS-422 Transceivers in µDFN
withstand voltage measured to IEC 61000-4-2 is gener-
ally lower than that measured using the Human Body
Model. Figure 10c shows the IEC 61000-4-2 model,
and Figure 10d shows the current waveform for the IEC
61000-4-2 ESD Contact Discharge test.
The machine model for ESD tests all pins using a 200pF
storage capacitor and zero discharge resistance.
The objective is to emulate the stress caused when I/O
pins are contacted by handling equipment during test
and assembly. Of course, all pins require this protec-
tion, not just RS-485 inputs and outputs.
The air-gap test involves approaching the device with a
charged probe. The contact-discharge method connects
the probe to the device before the probe is energized.
The standard RS-485 receiver input impedance is 12kΩ
(1-unit load), and the standard driver can drive up to
32-unit loads. The MAX13485E/MAX13486E have a 1/4-
unit load receiver input impedance (48kΩ), allowing up
to 128 transceivers to be connected in parallel on one
communication line. Any combination of these devices,
as well as other RS-485 transceivers with a total of 32-
unit loads or fewer, can be connected to the line.
The MAX13485E features reduced slew-rate drivers
that minimize EMI and reduce reflections caused by
improperly terminated cables, allowing error-free data
transmission up to 500kbps.
Figure 11. Typical Half-Duplex RS-485 Network
14
RO
______________________________________________________________________________________
DE
RE
DI
D
MAX13485E
MAX13486E
Applications Information
Reduced EMI and Reflections
128 Transceivers on the Bus
R
R
t
Machine Model
DI
D
DE
RO RE
R
Low-power shutdown mode is initiated by bringing both
RE high and DE low. In shutdown, the devices draw a
maximum of 10µA of supply current.
RE and DE can be driven simultaneously. The devices
are 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 700ns, the devices are guaranteed to
enter shutdown.
Enable times t
istics ) assume the devices were not in a low-power shut-
down state. Enable times t
assume the devices were in shutdown state. It takes dri-
vers and receivers longer to become enabled from low-
power shutdown mode (t
driver-/receiver-disable mode (t
The RS-485/RS-422 standard covers line lengths up to
4000ft.
The MAX13485E/MAX13486E transceivers are
designed for half-duplex, bidirectional data communi-
cations on multipoint bus transmission lines. Figure 11
shows typical network applications circuits. To mini-
mize reflections, terminate the line at both ends in its
characteristic impedance, and keep stub lengths off
the main line as short as possible. The slew-rate-limited
MAX13485E is more tolerant of imperfect termination.
PROCESS: BiCMOS
DI
D
DE
ZH
RO RE
R
and t
Low-Power Shutdown Mode
R
t
ZL
ZH(SHDN)
(see the Switching Character-
Chip Information
Typical Applications
ZH(SHDN)
ZH
, t
, t
ZL
ZL(SHDN)
R
).
and t
Line Length
D
) than from
ZL(SHDN)
DI
DE
RO
RE