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ADM1485AN

更新时间： 2024-02-21 00:14:50

品牌	Logo	应用领域
亚德诺 - ADI		/
页数	文件大小	规格书
8页	141K
描述
+-5 V Low Power EIA RS-485 Transceiver

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技术参数
数据手册

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ADM1485AN 技术参数

是否无铅：	含铅	是否Rohs认证：	符合
生命周期：	Active	零件包装代码：	SOIC
包装说明：	SOIC-8	针数：	8
Reach Compliance Code：	compliant	ECCN代码：	EAR99
HTS代码：	8542.39.00.01	风险等级：	0.7
Samacsys Confidence：	3	Samacsys Status：	Released
2D Presentation：	https://componentsearchengine.com/2D/0T/236838.1.2.png	Schematic Symbol：	https://componentsearchengine.com/symbol.php?partID=236838
PCB Footprint：	https://componentsearchengine.com/footprint.php?partID=236838	3D View：	https://componentsearchengine.com/viewer/3D.php?partID=236838
Samacsys PartID：	236838	Samacsys Image：	https://componentsearchengine.com/Images/9/ADM1485JRZ-REEL.jpg
Samacsys Thumbnail Image：	https://componentsearchengine.com/Thumbnails/1/ADM1485JRZ-REEL.jpg	Samacsys Pin Count：	8
Samacsys Part Category：	Integrated Circuit	Samacsys Package Category：	Small Outline Packages
Samacsys Footprint Name：	R-8 (SOIC)	Samacsys Released Date：	2015-11-06 07:15:09
Is Samacsys：	N	其他特性：	THERMAL SHUTDOWN PROTECTION
差分输出：	YES	驱动器位数：	1
高电平输入电流最大值：	0.000001 A	输入特性：	DIFFERENTIAL SCHMITT TRIGGER
接口集成电路类型：	LINE TRANSCEIVER	接口标准：	EIA-422; EIA-485
JESD-30 代码：	R-PDSO-G8	JESD-609代码：	e3
长度：	4.9 mm	湿度敏感等级：	1
功能数量：	1	端子数量：	8
最高工作温度：	70 °C	最低工作温度：
最小输出摆幅：	1.5 V	输出特性：	3-STATE
最大输出低电流：	0.004 A	输出极性：	COMPLEMENTARY
封装主体材料：	PLASTIC/EPOXY	封装代码：	SOP
封装等效代码：	SOP8,.25	封装形状：	RECTANGULAR
封装形式：	SMALL OUTLINE	峰值回流温度（摄氏度）：	260
电源：	5 V	认证状态：	Not Qualified
最大接收延迟：	40 ns	接收器位数：	1
座面最大高度：	1.75 mm	子类别：	Line Driver or Receivers
最大压摆率：	2.2 mA	最大供电电压：	5.25 V
最小供电电压：	4.75 V	标称供电电压：	5 V
表面贴装：	YES	技术：	BICMOS
温度等级：	COMMERCIAL	端子面层：	Matte Tin (Sn)
端子形式：	GULL WING	端子节距：	1.27 mm
端子位置：	DUAL	处于峰值回流温度下的最长时间：	30
最大传输延迟：	15 ns	宽度：	3.9 mm
Base Number Matches：	1

ADM1485AN 数据手册

ADM1485

showing a multipoint transmission network is illustrated in

Figure 26. An RS-485 transmission line can have as many as 32

transceivers on the bus. Only one driver can transmit at a par-

ticular time but multiple receivers may be enabled simultaneously.

APPLICATIONS INFORMATION

Differential Data Transmission

Differential data transmission is used to reliably transmit data at

high rates over long distances and through noisy environments.

Differential transmission nullifies the effects of ground shifts and

noise signals which appear as common-mode voltages on the

line. There are two main standards approved by the Electronics

Industries Association (EIA) which specify the electrical charac-

teristics of transceivers used in differential data transmission.

As with any transmission line, it is important that reflections are

minimized. This may be achieved by terminating the extreme

ends of the line using resistors equal to the characteristic im-

pedance of the line. Stub lengths of the main line should also be

kept as short as possible. A properly terminated transmission

line appears purely resistive to the driver.

The RS-422 standard specifies data rates up to 10 MBaud and

line lengths up to 4000 ft. A single driver can drive a transmis-

sion line with up to 10 receivers.

Thermal Shutdown

The ADM1485 contains thermal shutdown circuitry which

protects the part from excessive power dissipation during fault

conditions. Shorting the driver outputs to a low impedance

source can result in high driver currents. The thermal sensing

circuitry detects the increase in die temperature and disables the

driver outputs. The thermal sensing circuitry is designed to

disable the driver outputs when a die temperature of 150°C is

reached. As the device cools, the drivers are re-enabled at

140°C.

In order to cater for true multipoint communications, the

RS-485 standard was defined. This standard meets or exceeds

all the requirements of RS-422 but also allows for up to 32

drivers and 32 receivers to be connected to a single bus. An

extended common-mode range of –7 V to +12 V is defined. The

most significant difference between RS-422 and RS-485 is the

fact that the drivers may be disabled thereby allowing more than

one (32 in fact) to be connected to a single line. Only one driver

should be enabled at time, but the RS-485 standard contains

additional specifications to guarantee device safety in the event

of line contention.

Propagation Delay

The ADM1485 features very low propagation delay ensuring

maximum baud rate operation. The driver is well balanced

ensuring distortion free transmission.

Cable and Data Rate

The transmission line of choice for RS-485 communications is a

twisted pair. Twisted pair cable tends to cancel common-mode

noise and also causes cancellation of the magnetic fields gener-

ated by the current flowing through each wire, thereby, reducing

the effective inductance of the pair.

Another important specification is a measure of the skew be-

tween the complementary outputs. Excessive skew impairs the

noise immunity of the system and increases the amount of elec-

tromagnetic interference (EMI).

Receiver Open-Circuit Fail Safe

The ADM1485 is designed for bidirectional data communica-

tions on multipoint transmission lines. A typical application

The receiver input includes a fail-safe feature which guarantees

a logic high on the receiver when the inputs are open circuit or

floating.

Table III. Comparison of RS-422 and RS-485 Interface Standards

Specification

RS-422

RS-485

Transmission Type

Differential

4000 ft.

2 V

Differential

4000 ft.

1.5 V

Maximum Cable Length

Minimum Driver Output Voltage

Driver Load Impedance

100 Ω

54 Ω

Receiver Input Resistance

Receiver Input Sensitivity

Receiver Input Voltage Range

No of Drivers/Receivers Per Line

4 kΩ min

200 mV

–7 V to +7 V

1/10

12 kΩ min

200 mV

–7 V to +12 V

32/32

REV. A

–7–

1...4 5 678

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与ADM1485AN相关器件

型号	品牌	描述	获取价格	数据表
ADM1485ANZ	ADI	5 V Low Power EIA RS-485 Transceiver	获取价格
ADM1485ANZ	ROCHESTER	LINE TRANSCEIVER, PDIP8, PLASTIC, MO-095AA, DIP-8	获取价格
ADM1485AQ	ADI	+-5 V Low Power EIA RS-485 Transceiver	获取价格
ADM1485AR	ADI	+-5 V Low Power EIA RS-485 Transceiver	获取价格
ADM1485AR	ROCHESTER	LINE TRANSCEIVER, PDSO8, MS-012AA, SOIC-8	获取价格
ADM1485ARM	ADI	5 V, High Speed (30 Mbps), Low Power, Half Duplex EIA RS-485 Transceiver	获取价格

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