|
|
PDF MAX14781E Data sheet ( Hoja de datos )
| Número de pieza | MAX14781E | |
| Descripción | Half-Duplex RS-485 Transceiver | |
| Fabricantes | Maxim Integrated | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de MAX14781E (archivo pdf) en la parte inferior de esta página. Total 19 Páginas | ||
|
No Preview Available !
MAX14781E
Half-Duplex RS-485 Transceiver
with Polarity Correction
General Description
The MAX14781E +5V, half-duplex ±25kV ESD-protected
RS-485 transceiver features integrated automatic polar-
ity correction to ensure that miswired A and B lines are
autonomously corrected, simplifying equipment and net-
work installation.
The MAX14781E includes slew-rate limited drivers that
minimize EMI, allowing for error-free data transmission
up to 370kbps.
This device includes fail-safe circuitry, guaranteeing a
logic-high receiver output when the receiver inputs are
shorted or open. Hot-swap functionality on the receiver
and driver enable inputs also eliminates false transitions
on the bus during power-up or live insertion.
The MAX14781E features a 1/8-unit load receiver input
impedance, allowing up to 256 transceivers on the bus. All
driver outputs are protected up to ±25kV ESD using the
Human Body Model. The MAX14781E is available in an
8-pin SO package and operates over the extended -40°C
to +85°C temperature range.
Applications
●● Power Meter Networks
●● HVAC Networks
●● Control Systems
Benefits and Features
●● Automatic Polarity Correction
●● Integrated Protection Increases Robustness
• High ESD Protection
±25kV HBM ESD
±15kV IEC 61000-4-2 Air Gap Discharge ESD
±9kV IEC 61000-4-2 Contact Discharge ESD
• True Fail-Safe Receiver
• Hot-Swap Functionality
●● +5V Operation
●● Low 10µA (max) Shutdown Current
●● Extended -40°C to +85°C Operating Temperature
Ordering Information appears at end of data sheet.
For related parts and recommended products to use with this part, refer
to www.maximintegrated.com/MAX14781E.related.
Functional Diagram
RO R
RE
DE
DI D
MAX14781E
POLARITY
CORRECT
A
B
19-6859; Rev 0; 12/13
1 page  
MAX14781E
Half-Duplex RS-485 Transceiver
with Polarity Correction
Switching Characteristics (continued)
(VCC = 5V ± 10%, TA = -40°C to +85°C, unless otherwise noted. Typical values are at VCC = 5V and TA = +25°C.)(Notes 2, 3)
PARAMETER
SYMBOL
CONDITIONS
MIN TYP MAX
UNITS
Receiver Enable to Output Low
tRZL
RL = 1kΩ, CL = 15pF, Figure 8
(Note 9)
50 ns
Receiver Disable Time from Low
tRLZ
RL = 1kΩ, CL = 15pF, Figure 8
(Note 9)
50 ns
Receiver Disable Time from High
tRHZ
RL = 1kΩ, CL = 15pF, Figure 8
(Note 9)
50 ns
Receiver Enable from Shutdown
to Output High
tRZH(SHDN)
RL = 1kΩ, CL = 15pF, Figure 8
(Note 9)
5.5 μs
Receiver Enable from Shutdown
to Output Low
tRZL(SHDN)
RL = 1kΩ, CL = 15pF, Figure 8
(Note 9)
5.5 μs
Time to Shutdown
tSHDN
(Note 10)
50 340 700
ns
Note 2: All devices are 100% production tested at TA = +25°C. Spefications over temperature are guaranteed by design.
Note 3: All currents into the device are positive. All currents out of the device are negative. All voltages are referenced to ground,
unless otherwise noted.
Note 4: ΔVOD and ΔVOC are the changes in VOD and VOC, respectively, when the DI input changes state.
Note 5: The short-circuit output current applies to the peak current just prior to foldback current limiting. The short-circuit foldback
output current applies during current limiting to allow recovery from a bus contention.
Note 6: tPM is the interval, with no A/B switching activity, after which the internal logic circuitry records the polarity. tPM includes the
correction delay, after which the polarity is changed.
Note 7: Not production tested. Guaranteed by design.
Note 8: Capacitive loads include test probe and fixture capacitance.
Note 9: This parameter refers to the driver/receiver enable delay when the device has exited the initial hot-swap state and is in nor-
mal operating mode.
Note 10: Shutdown is enabled by driving RE high and DE low. The device is guaranteed to have entered shutdown after tSHDN has
elapsed.
www.maximintegrated.com
Maxim Integrated │ 5
5 Page 
MAX14781E
Pin Configuration
Half-Duplex RS-485 Transceiver
with Polarity Correction
TOP VIEW
RO 1
+
RE 2
MAX14781E
DE 3
DI 4
SO
8 VCC
7B
6A
5 GND
Pin Description
PIN NAME
FUNCTION
1
RO
Receiver Output. See the Receiving Functional Table for details. RO is high impedance when RE is
high.
Receiver Output Enable. Drive RE low to enable RO. RO is high impedance when RE is high. Drive
2 RE RE high and DE low to enter low-power shutdown mode. RE is a hot-swap input (see the Hot Swap
Capability section for details).
Driver Output Enable. Drive DE high to enable driver outputs. These outputs are high impedance
3 DE when DE is low. Drive RE high and DE low to enter low-power shutdown mode. DE is a hot-swap
input (see the Hot-Swap Capability section for details).
4 DI Driver Input. See the Transmitting Functional Table for details.
5
GND
Ground
6 A Noninverting Receiver Input/Driver Output*
7 B Inverting Receiver Input/Driver Output*
8
VCC
Positive Supply. Bypass VCC to GND with a 0.1µF capacitor.
*This is the default polarity at power-up. In case of polarity correction, A becomes the inverting receiver input/driver output and the B
is the noninverting receiver input/driver output.
www.maximintegrated.com
Maxim Integrated │ 11
11 Page | ||
| Páginas | Total 19 Páginas | |
| PDF Descargar | [ Datasheet MAX14781E.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| MAX14781E | Half-Duplex RS-485 Transceiver | Maxim Integrated |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |