参数资料
型号: MAX1490AEPG
厂商: MAXIM INTEGRATED PRODUCTS INC
元件分类: 通用总线功能
英文描述: Complete, Isolated RS-485/RS-422 Data Interface
中文描述: LINE TRANSCEIVER, PDIP24
封装: PLASTIC, DIP-24
文件页数: 18/21页
文件大小: 487K
代理商: MAX1490AEPG
M
Complete, Isolated RS-485/RS-422
Data Interface
18
______________________________________________________________________________________
Driver Output Protection
There are two mechanisms to prevent excessive output
current and power dissipation caused by faults or by
bus contention. A foldback current limit on the output
stage provides immediate protection against short cir-
cuits over the entire common-mode range (see the
Typical Operating Characteristics
). In addition, a ther-
mal shutdown circuit forces the driver outputs into a
high-impedance state if the die temperature rises
excessively.
Propagation Delay Skew
Typical propagation delays are shown in the
Typical
Operating Characteristics
using the test circuit of
Figure 5. Propagation delay skew is simply the differ-
ence between the low-to-high and high-to-low propaga-
tion delay. Small driver/receiver skew times help
reduce EMI and reflections by maintaining balanced
differential signals.
The receiver skew time,
I
t
PLH
- t
PHL
I
, is typically under
100ns for the MAX1480A/MAX1490A and under 1μs for
the MAX1480B/MAX1480C/MAX1490B.
The driver skew time is typically 25ns for the
MAX1480A/MAX1490A and 100ns for the MAX1480B/
MAX1480C/MAX1490B.
___________Applications Information
DI and DE are intended to be driven through a
series current-limiting resistor. Directly grounding
these pins destroys the device.
The MAX1480A/MAX1480B/MAX1480C are designed
for bidirectional data communications on multipoint
bus-transmission lines. The MAX1490A/MAX1490B are
designed for full-duplex bidirectional communications
that are primarily point-to-point. Figures 13 and 14
show half-duplex and full-duplex typical network appli-
cation circuits, respectively. To minimize reflections,
terminate the line at both ends with its characteristic
impedance, and keep stub lengths off the main line as
short as possible. The slew-rate-limited MAX1480B/
MAX1480C/MAX1490B are more tolerant of imperfect
termination and stubs off the main line.
Layout Considerations
The MAX1480A/MAX1480B/MAX1480C/MAX1490A/
MAX1490B pinouts enable optimal PC board layout by
minimizing interconnect lengths and crossovers.
For maximum isolation, the “isolation barrier” should
not be breached except by the MAX1480A/
MAX1480B/MAX1480C/MAX1490A/MAX1490B.
SHIELD (OPTIONAL)
NOTE: RESISTORS R5 AND R6 PROTECT
THE MAX1490A/B FROM TRANSIENT
CURRENTS BETWEEN SHIELD AND
TRANSMISSION LINES.
120
120
120
A
B
Z
Y
Y
Z
R3
R4
R5, 100
SH1
SH2
R1
R2
R6, 100
DI
V
IN
5V
22
μ
F
0.1
μ
F
C1
C2
MAX1490A/B
LOGIC GROUND
ISOLATION BARRIER
ISOLATED COMMON
DRIVER INPUT
RECEIVER OUTPUT
DI
RO
74HC86
OR EQUIVALENT
SHIELD (OPTIONAL)
24
23
22
21
20
19
18
17
1
2
3
4
5
6
7
8
AC1 (MAKE NO CONNECTION)
AC2 (MAKE NO CONNECTION)
ISO V
CC1
ISO RO DRV
D2
D1
V
CC2
V
CC1
A
B
Z
Y
V
CC3
SD
FS
GND1
16
15
14
13
9
10
11
12
ISO COM1
ISO DI DRV
ISO V
CC2
ISO RO LED
GND2
RO
V
CC4
DI
M
M
M
D
DI
RO
120
B
A
R
Figure 14. Typical Full-Duplex RS-485/RS-422 Network
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MAX1490AEPG+ 功能描述:RS-422/RS-485 接口 IC Isolated RS-485/422 Data Interface RoHS:否 制造商:Maxim Integrated 数据速率:1136 Kbps 工作电源电压:3 V to 5.5 V 电源电流:5.9 mA 工作温度范围:- 40 C to + 85 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-28 封装:Tube
MAX1490BCPG 功能描述:RS-422/RS-485 接口 IC RoHS:否 制造商:Maxim Integrated 数据速率:1136 Kbps 工作电源电压:3 V to 5.5 V 电源电流:5.9 mA 工作温度范围:- 40 C to + 85 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-28 封装:Tube
MAX1490BCPG+ 功能描述:RS-422/RS-485 接口 IC Isolated RS-485/422 Data Interface RoHS:否 制造商:Maxim Integrated 数据速率:1136 Kbps 工作电源电压:3 V to 5.5 V 电源电流:5.9 mA 工作温度范围:- 40 C to + 85 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-28 封装:Tube
MAX1490BEPG 功能描述:RS-422/RS-485 接口 IC RoHS:否 制造商:Maxim Integrated 数据速率:1136 Kbps 工作电源电压:3 V to 5.5 V 电源电流:5.9 mA 工作温度范围:- 40 C to + 85 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-28 封装:Tube
MAX1490BEPG+ 功能描述:RS-422/RS-485 接口 IC Isolated RS-485/422 Data Interface RoHS:否 制造商:Maxim Integrated 数据速率:1136 Kbps 工作电源电压:3 V to 5.5 V 电源电流:5.9 mA 工作温度范围:- 40 C to + 85 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-28 封装:Tube