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| 型号： | MAX13442EASA+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 5/18页 |
| 文件大小： | 0K |
| 描述： | IC TXRX RS485 HALF DUPLEX 8-SOIC |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| 类型： | 收发器 |
| 驱动器/接收器数： | 1/1 |
| 规程： | RS422，RS485 |
| 电源电压： | 4.75 V ~ 5.25 V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 8-SOIC（0.154"，3.90mm 宽） |
| 供应商设备封装： | 8-SOIC |
| 包装： | 带卷 (TR) |
MAX13442E/MAX13443E/MAX13444E
±15kV ESD-Protected, ±80V Fault-Protected,
Fail-Safe RS-485/J1708 Transceivers
______________________________________________________________________________________
13
Detailed Description
The MAX13442E/MAX13443E/MAX13444E fault-protect-
ed transceivers for RS-485/RS-422 and J1708 communi-
cation contain one driver and one receiver. These
devices feature fail-safe circuitry, which guarantees a
logic-high receiver output when the receiver inputs are
open or shorted, or when they are connected to a termi-
nated transmission line with all drivers disabled (see the
True Fail-Safe section). All devices have a hot-swap input
structure that prevents disturbances on the differential
signal lines when a circuit board is plugged into a hot
backplane (see the
Hot-Swap Capability section). The
MAX13442E/MAX13444E feature a reduced slew-rate dri-
ver that minimizes EMI and reduces reflections caused
by improperly terminated cables, allowing error-free data
transmission up to 250kbps (see the
Reduced EMI and
Reflections section). The MAX13443E driver is not slew-
rate limited, allowing transmit speeds up to 10Mbps.
Driver
The driver accepts a single-ended, logic-level input
(DI) and transfers it to a differential, RS-485/RS-422
level output (A and B). Deasserting the driver enable
places the driver outputs (A and B) into a high-imped-
ance state.
Receiver
The receiver accepts a differential, RS-485/RS-422
level input (A and B), and transfers it to a single-ended,
logic-level output (RO). Deasserting the receiver enable
places the receiver inputs (A and B) into a high-imped-
ance state (see Tables 1–4).
Low-Power Shutdown
The MAX13442E/MAX13443E/MAX13444E offer a low-
power shutdown mode. Force DE low and RE high to
shut down the MAX13442E/MAX13443E. Force DE and
RE high to shut down the MAX13444E. A time delay of
50ns prevents the device from accidentally entering
shutdown due to logic skews when switching between
transmit and receive modes. Holding DE low and RE
high for at least 800ns guarantees that the
MAX13442E/MAX13443E enter shutdown. In shutdown,
the devices consume a maximum 20A supply current.
±80V Fault Protection
The driver outputs/receiver inputs of RS-485 devices in
industrial network applications often experience voltage
faults resulting from shorts to the power grid that exceed
the -7V to +12V range specified in the EIA/TIA-485 stan-
dard. In these applications, ordinary RS-485 devices
(typical absolute maximum -8V to +12.5V) require costly
external protection devices. To reduce system complexi-
ty and eliminate this need for external protection, the dri-
ver outputs/receiver inputs of the MAX13442E/
MAX13444E withstand voltage faults up to
±80V (±60V
for the MAX13443E) with respect to ground without dam-
age. Protection is guaranteed regardless whether the
device is active, shut down, or without power.
True Fail-Safe
The MAX13442E/MAX13443E/MAX13444E use a
-50mV to -200mV differential input threshold to ensure
true fail-safe receiver inputs. This threshold guarantees
the receiver outputs a logic-high for shorted, open, or
idle data lines. The -50mV to -200mV threshold com-
plies with the ±200mV threshold EIA/TIA-485 standard.
±15kV ESD Protection
As with all Maxim devices, ESD-protection structures
are incorporated on all pins to protect against ESD
encountered during handling and assembly. The
MAX13442E/MAX13443E/MAX13444E receiver inputs/
driver outputs (A, B) have extra protection against stat-
ic electricity found in normal operation. Maxim’s engi-
neers have developed state-of-the-art structures to
protect these pins against ±15kV ESD without damage.
After an ESD event, the MAX13442E/MAX13443E/
MAX13444E continue working without latchup.
ESD protection can be tested in several ways. The
receiver inputs are characterized for protection to
±15kV using the Human Body Model.
ESD Test Conditions
ESD performance depends on a number of conditions.
Contact Maxim for a reliability report that documents
test setup, methodology, and results.
Human Body Model
Figure 9a shows the Human Body Model, and Figure
9b 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 inter-
est, which is then discharged into the device through a
1.5k
Ω resistor.
Driver Output Protection
Two mechanisms prevent excessive output current and
power dissipation caused by faults or bus contention.
The first, a foldback current limit on the driver output
stage, provides immediate protection against short cir-
cuits over the whole common-mode voltage range. The
second, a thermal shutdown circuit, forces the driver out-
puts into a high-impedance state if the die temperature
exceeds +160°C. Normal operation resumes when the
die temperature cools to +140°C, resulting in a pulsed
output during continuous short-circuit conditions.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX13443EASA | 功能描述:RS-485接口IC RoHS:否 制造商:Texas Instruments 数据速率:250 Kbps 工作电源电压:3.3 V 电源电流:750 uA 工作温度范围:- 40 C to + 125 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Tube |
| MAX13443EASA+ | 功能描述:RS-485接口IC Half-Dplx RS-422/485 10Msps 5V LD/Rec RoHS:否 制造商:Texas Instruments 数据速率:250 Kbps 工作电源电压:3.3 V 电源电流:750 uA 工作温度范围:- 40 C to + 125 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Tube |
| MAX13443EASA+T | 功能描述:RS-485接口IC Half-Dplx RS-422/485 10Msps 5V LD/Rec RoHS:否 制造商:Texas Instruments 数据速率:250 Kbps 工作电源电压:3.3 V 电源电流:750 uA 工作温度范围:- 40 C to + 125 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Tube |
| MAX13443EASA-T | 功能描述:RS-485接口IC RoHS:否 制造商:Texas Instruments 数据速率:250 Kbps 工作电源电压:3.3 V 电源电流:750 uA 工作温度范围:- 40 C to + 125 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Tube |
| MAX13444EASA | 功能描述:RS-485接口IC RoHS:否 制造商:Texas Instruments 数据速率:250 Kbps 工作电源电压:3.3 V 电源电流:750 uA 工作温度范围:- 40 C to + 125 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Tube |
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