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参数资料
| 型号： | SP3238ECA-L/TR |
| 厂商： | Exar Corporation |
| 文件页数： | 18/20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 |
Exar Corporation 48720 Kato Road, Fremont CA, 94538 510-668-7017 www.exar.com
SP3238E_100_020111
7
DESCRIPTION
The SP3238E device meets the EIA/TIA-232
and ITU-T V.28/V.24 communication protocols
and can be implemented in battery-powered,
portable, or hand-held applications such as
notebook or palmtop computers. The SP3238E
devices feature Exar's proprietary and patented
(U.S.-- 5,306,954) on-board charge pump cir-
cuitrythatgenerates±5.5VRS-232voltagelevels
from a single +3.0V to +5.5V power supply. The
SP3238E devices can guarantee a data rate of
250kbps fully loaded.
The SP3238E is a 5-driver/3-receiver device,
ideal for portable or hand-held applications.
The SP3238E includes one complementary
always-active receiver that can monitor an
external device (such as a modem) in shutdown.
This aids in protecting the UART or serial
controller IC by preventing forward biasing
of the protection diodes where V
CC may be
disconnected.
The SP3238E device is an ideal choice for power
sensitive designs.The SP3238E device features
AUTO ON-LINE circuitry which reduces the
power supply drain to a 1A supply current.
In many portable or hand-held applications, an
RS-232cablecanbedisconnectedoraconnected
peripheral can be turned off. Under these condi-
tions,theinternalchargepumpandthedriverswill
be shut down. Otherwise, the system automati-
cally comes online. This feature allows design
engineers to address power saving concerns
without major design changes.
THEORY OF OPERATION
The SP3238E device is made up of four basic
circuit blocks:
1. Drivers
2. Receivers
3. The Exar proprietary charge pump, and
4.
AUTO ON-LINE circuitry.
Drivers
The drivers are inverting level transmitters that
convert TTL or CMOS logic levels to 5.0V EIA/
TIA-232 levels with an inverted sense relative
to the input logic levels. Typically, the RS-232
output voltage swing is +5.4V with no load and
+5V minimum fully loaded. The driver outputs are
protected against infinite short-circuits to ground
without degradation in reliability. These drivers
comply with the EIA-TIA-232-F and all previous
RS-232 versions.
The drivers can guarantee a data rate of 250kbps
fully loaded with 3k in parallel with 1000pF,
ensuring compatibility with PC-to-PC communi-
cation software. All unused drivers inputs should
be connected to GND or V
CC.
The slew rate of the driver output is internally
limited to a maximum of 30V/s in order to meet
theEIAstandards(EIARS-232D2.1.7,Paragraph
5). The transition of the loaded output from HIGH
toLOWalsomeetsthemonotonicityrequirements
of the standard.
Figure 7 shows a loopback test circuit used to
test the RS-232 drivers. Figure 8 shows the test
results of the loopback circuit with all five drivers
active at 120kbps with typical RS-232 loads in
parallel with 1000pF capacitors. Figure 9 shows
the test results where one driver was active
at 250kbps and all five drivers loaded with an
RS-232 receiver in parallel with a 1000pF ca-
pacitor. A solid RS-232 data transmission rate
of 120kbps provides compatibility with many
designs in personal computer peripherals and
LAN applications.
Figure 6. Interface Circuitry Controlled by
Microprocessor Supervisory Circuit
SP3238E
28
25
3
1
27
4
26
GND
C1+
C1-
C2+
C2-
V+
V-
VCC
0.1F
+
C2
C5
C1
+
C3
C4
+
13
14
15
VCC
2
ONLINE
SHUTDOWN
STATUS
P
Supervisor
IC
VCC
VIN
RESET
5k
24
23
22
16
21
20
18
5
6
7
8
9
11
RS-232
OUTPUTS
RS-232
INPUTS
T1IN
R1OUT
R1IN
T2OUT
R1OUT
T2IN
T3IN
T3OUT
T1OUT
R2IN
R3IN
R2OUT
R3OUT
UART
or
Serial C
TxD
RTS
DTR
RxD
CTS
DSR
DCD
RI
19
17
10
12
T4OUT
T4IN
T5IN
T5OUT
0.1F
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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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