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参数资料
| 型号： | SP3238ECA-L/TR |
| 厂商： | Exar Corporation |
| 文件页数： | 4/20页 |
| 文件大小： | 0K |
| 描述： | IC TXRX RS232 INTELLIGENT 28SSOP |
| 标准包装： | 1,500 |
| 类型： | 收发器 |
| 驱动器/接收器数： | 5/3 |
| 规程： | RS232 |
| 电源电压： | 3 V ~ 5.5 V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 28-SSOP（0.209"，5.30mm 宽） |
| 供应商设备封装： | 28-SSOP |
| 包装： | 带卷 (TR) |
| 其它名称： | SP3238ECA-L/TR-ND |
12
Exar Corporation 48720 Kato Road, Fremont CA, 94538 510-668-7017 www.exar.com
SP3238E_100_020111
The first stage, shown in Figure 17, detects an
inactive input. A logic HIGH is asserted on
R
XINACT if the cable is disconnected or the
external transmitters are disabled. Otherwise,
R
XINACT will be at a logic LOW. This circuit is
duplicated for each of the other receivers.
The second stage of the
AUTO ON-LINE
circuitry, shown in Figure 18, processes all the
receiver's R
XINACT signals with an accumulated
delay that disables the device to a 1A supply
current. The STATUS pin goes to a logic LOW
when the cable is disconnected, the external
transmitters are disabled, or the SHUTDOWN
pin is invoked. The typical accumulated delay is
around 20s. When the SP3238E drivers or inter-
nal charge pump are disabled, the supply current
is reduced to 1A. This can commonly occur in
handheld or portable applications where
The SP3238E device has a patent pending
AUTO ON-LINE circuitry on board that saves
power in applications such as laptop computers,
palmtop (PDA) computers and other portable
systems.
The SP3238E device incorporates an
AUTO
ON-LINE circuit that automatically enables itself
when the external transmitters are enabled and
the cable is connected. Conversely, the
AUTO
ON-LINE circuit also disables most of the inter-
nal circuitry when the device is not being used
and goes into a standby mode where the device
typically draws 1A. This function is externally
controlled by the ONLINE pin. When this pin is
tied to a logic LOW, the
AUTO ON-LINE func-
tion is active. Once active, the device is enabled
until there is no activity on the receiver inputs.
The receiver input typically sees at least +3V,
which are generated from the transmitters at
the other end of the cable with a +5V minimum.
When the external transmitters are disabled or
the cable is disconnected, the receiver inputs will
be pulled down by their internal 5k resistors to
ground. When this occurs over a period of time,
the internal transmitters will be disabled and the
device goes into a shutdown or standby mode.
When ONLINE is HIGH, the
AUTO ON-LINE
mode is disabled.
The
AUTO ON-LINE circuit has two stages:
1) Inactive Detection
2) Accumulated Delay
AUTO ONLINE CIRCUITRY
the RS-232 cable is disconnected or the RS-232
drivers of the connected peripheral are turned
off.
The
AUTO ON-LINE mode can be disabled by
the SHUTDOWN pin. If this pin is a logic LOW,
the
AUTO ON-LINE function will not operate
regardless of the logic state of the ONLINE pin.
Table 3 summarizes the logic of the
AUTO ON-
LINE operating modes.
The STATUS pin outputs a logic LOW signal if
the device is shutdown. This pin goes to a logic
HIGH when the external transmitters are enabled
and the cable is connected.
When the SP3238E device is shutdown, the
charge pumps are turned off. V+ charge pump
output decays to V
CC, the V- output decays to
GND. The decay time will depend on the size
of capacitors used for the charge pump. Once
in shutdown, the time required to exit the shut
down state and have valid V+ and V- levels is
typically 200ms.
For easy programming, the STATUS can
be used to indicate DTR or a Ring Indica-
tor signal. Tying ONLINE and SHUTDOWN
together will bypass the
AUTO ON-LINE cir-
cuitry so this connection acts like a shutdown
input pin
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相关代理商/技术参数 |
参数描述 |
|---|---|
| SP3238ECY | 制造商:Rochester Electronics LLC 功能描述: 制造商:Exar Corporation 功能描述: |
| SP3238ECY/TR | 制造商:Rochester Electronics LLC 功能描述: 制造商:Exar Corporation 功能描述: |
| SP3238ECY-L | 功能描述:RS-232接口集成电路 Intel. +3V to +5.5V RS-232 RoHS:否 制造商:Exar 数据速率:52 Mbps 工作电源电压:5 V 电源电流:300 mA 工作温度范围:- 40 C to + 85 C 安装风格:SMD/SMT 封装 / 箱体:LQFP-100 封装: |
| SP3238ECY-L/TR | 功能描述:RS-232接口集成电路 Intel. +3V to +5.5V RS-232 RoHS:否 制造商:Exar 数据速率:52 Mbps 工作电源电压:5 V 电源电流:300 mA 工作温度范围:- 40 C to + 85 C 安装风格:SMD/SMT 封装 / 箱体:LQFP-100 封装: |
| SP3238EE | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:Intelligent +3.0V to +5.5V RS-232 Transceiver |
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