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| 型号： | SP211CA-L |
| 厂商： | Exar Corporation |
| 文件页数： | 10/14页 |
| 文件大小： | 0K |
| 描述： | IC TXRX RS232 SERIAL 28SSOP |
| 标准包装： | 46 |
| 类型： | 收发器 |
| 驱动器/接收器数： | 4/5 |
| 规程： | RS232 |
| 电源电压： | 4.5 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： | 管件 |
| 其它名称： | SP211CA-L-ND |
5
Exar Corporation 48720 Kato Road, Fremont CA, 94538 (50)668-7000 Fax (50)668-707 www.exar.com SP206, 207, 208, 2_0_060
DESCRIPTION
FEATURES
The SP206/207/208/2 multi-channel RS-232
line transceivers provide a variety of configu-
rations to fit most communication needs, es-
pecially those applications where +/-2V is not
available. All models in this series feature low-
power CMOS construction and Exar's proprie-
tary on-board charge pump circuitry to generate
the +/-0V RS-232 voltage levels. The ability to
use 0.F charge pump capacitors saves board
space and reduces circuit cost. Different mod-
els within the series provide different driver/re-
ceiver combinations to match any application
requirement.
The SP206 and SP2 models feature a low-
power shutdown mode that reduces power sup-
ply drain to A.
The models in this series are available in 24-pin
and 28-pin SO (wide) and SSOP (shrink) small
outline packages. Devices can be specified for
commercial (0C to +70C) or industrial/extend-
ed (-40C to +85C) operating temperatures.
THEORY OF OPERATION
CHARgE PUMP
The charge pump is an Exar patented design
and uses a unique approach compared to older
less-efficient designs. The charge pump still
requires four external capacitors, but uses a
four phase voltage shifting technique to attain
symmetrical +/-0V power supplies. Figure a
shows the waveform found on the positive side
of capacitor C2 and Figure 3b shows the nega-
tive side of capacitor C2. There is a free-run-
ning oscillator that controls the four phases of
the voltage shifting. A description of each phase
follows:
PHASE 1
Vss charge storage - During this phase of the
clock cycle, the positive side of capacitors C
and C2 are initially charged to +5V. C+ is then
switched to ground and the charge in C- is
transferred to C2-. Since C2+ is connected to
+5V, the voltage potential across capacitor C2
is now 0V.
PHASE 2
Vss transfer: Phase two of the clock connects
the negative terminal of C2 to the Vss stor-
age capacitor and the positive terminal of C2
to ground, and transfers the generated -0V to
C3. Simultaneously, the positive side of capaci-
tor C is switched to +5V and the negative side
is connected to ground.
PHASE 3
Vdd charge storage: The third phase of the
clock is identical to the first phase. The charge
transferred in C produces -5V in the negative
terminal of C, which is applied to the negative
side of C2. Since C2+ is at +5V, the voltage po-
tential across C2 is 0V.
PHASE 4
Vdd transfer: The fourth phase of the clock con-
nects the negative terminal of C2 to ground,
and transfers the generated 0V across C2 to
C4, the Vdd storage capacitor. Again, simulta-
neously with this, the positive side of capaci-
tor C is switched to +5V and the negative side
is connected to ground, and the cycle begins
again.
Since both V+ and V- are separately generated
from Vcc; in a no-load condition V+ and V- will
be symmetrical. Older charge pump approach-
es that generate V- from V+ will show a de-
crease in magnitude of V- compared to V+ due
to the inherent inefficiencies in the design.
The clock rate for the charge pump typically op-
erates at greater than 5kHz allowing the pump
to run efficiently with small 0.1uF capacitors
with a 6V breakdown voltage rating.
The SP206/207/208/2 devices are made up
of three basic circuit blocks - ) transmitter/
driver, 2) receiver and 3) charge pump. Each
model within the series incorporates variations
of these circuit to achieve the desired configu-
ration and performance.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| SP211CA-L/TR | 功能描述:RS-232接口集成电路 5V 4-DRVR/5-RCVR RS-232 0-70C 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: |
| SP211CT | 制造商:Exar Corporation 功能描述: |
| SP211CT/TR | 制造商:Exar Corporation 功能描述: |
| SP211CT-L | 功能描述:RS-232接口集成电路 5V 4-DRVR/5-RCVR RS-232 0-70C 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: |
| SP211CT-L/TR | 功能描述:RS-232接口集成电路 5V 4-DRVR/5-RCVR RS-232 0-70C 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: |
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