参数资料
| 型号： | ISL4270EIRZ |
| 厂商： | Intersil |
| 文件页数： | 13/13页 |
| 文件大小： | 0K |
| 描述： | IC 3DRVR/3RCVR RS232 3V 32-QFN |
| 标准包装： | 60 |
| 类型： | 收发器 |
| 驱动器/接收器数： | 3/3 |
| 规程： | RS232 |
| 电源电压： | 3 V ~ 5.5 V |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 32-VFQFN 裸露焊盘 |
| 供应商设备封装： | 32-QFN 裸露焊盘（5x5） |
| 包装： | 管件 |
9
FN6041.2
June 16, 2010
“INVALID DRIVING FORCEON AND FORCEOFF” section
of Table 2 for an operational summary. This operational
mode is perfect for handheld devices that communicate with
another computer via a detachable cable. Detaching the
cable allows the internal receiver pull-down resistors to pull
the inputs to GND (an invalid RS-232 level), causing the
30
μs timer to time-out and drive the IC into powerdown.
Reconnecting the cable restores valid levels, causing the IC
to power back up.
Hybrid Automatic Powerdown Options
For devices which communicate only through a detachable
cable, connecting INVALID to FORCEOFF (with
FORCEON = 0) may be a desirable configuration. While the
cable is attached INVALID and FORCEOFF remain high, so
the enhanced automatic powerdown logic powers down the
RS-232 device whenever there is 30 seconds of inactivity on
the receiver and transmitter inputs. Detaching the cable
allows the receiver inputs to drop to an invalid level (GND),
so INVALID switches low and forces the RS-232 device to
power down. The ISL4270E remains powered down until the
cable is reconnected (INVALID = FORCEOFF = 1) and a
transition occurs on a receiver or transmitter input (see
Figure 5). For immediate power up when the cable is
reattached, connect FORCEON to FORCEOFF through a
network similar to that shown in Figure 3.
Capacitor Selection
The ISL4270E charge pumps require only 0.1
μF capacitors
for the full operational voltage range. Table 3 lists other
acceptable capacitor values for various supply voltage
ranges. Do not use values smaller than those listed in
Table 3. Increasing the capacitor values (by a factor of 2)
reduces ripple on the transmitter outputs and slightly
reduces power consumption.
When using minimum required capacitor values, make sure
that capacitor values do not degrade excessively with
temperature. If in doubt, use capacitors with a larger nominal
value. The capacitor’s equivalent series resistance (ESR)
usually rises at low temperatures and it influences the
amount of ripple on V+ and V-.
Power Supply Decoupling
In most circumstances a 0.1
μF bypass capacitor is
adequate. In applications that are particularly sensitive to
power supply noise, decouple VCC to ground with a
capacitor of the same value as the charge-pump capacitor C1.
Connect the bypass capacitor as close as possible to the IC.
Transmitter Outputs when Exiting
Powerdown
Figure 8 shows the response of two transmitter outputs
when exiting powerdown mode. As they activate, the two
transmitter outputs properly go to opposite RS-232 levels,
with no glitching, ringing, nor undesirable transients. Each
transmitter is loaded with 3k
Ω in parallel with 2500pF. Note
that the transmitters enable only when the magnitude of the
supplies exceed approximately 3V.
TABLE 3. REQUIRED CAPACITOR VALUES
VCC
(V)
C1
(
μF)
C2, C3, C4
(
μF)
3.0 to 3.6
0.1
4.5 to 5.5
0.047
0.33
3.0 to 5.5
0.22
1
RECEIVER
INPUTS
TRANSMITTER
OUTPUTS
INVALID
OUTPUT
V+
VCC
0
V-
tINVL
tINVH
FIGURE 7. ENHANCED AUTOMATIC POWERDOWN AND INVALID TIMING DIAGRAMS
TRANSMITTER
INPUTS
tWU
tAUTOPWDN
tWU
INVALID
REGION
}
ISL4270E
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相关代理商/技术参数 |
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|---|---|
| ISL4270EIRZ-T | 功能描述:IC XMITTER/RCVR ESD RS232 32-QFN RoHS:是 类别:集成电路 (IC) >> 接口 - 驱动器，接收器，收发器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:50 系列:- 类型:收发器 驱动器/接收器数:1/1 规程:RS422，RS485 电源电压:4.75 V ~ 5.25 V 安装类型:通孔 封装/外壳:8-DIP（0.300"，7.62mm） 供应商设备封装:8-PDIP 包装:管件 产品目录页面:1402 (CN2011-ZH PDF) |
| ISL43110 | 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:Low-Voltage, Single Supply, SPST, High Performance Analog Switches |
| ISL43110_05 | 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:Low-Voltage, Single Supply, SPST, High Performance Analog Switches |
| ISL43110IB | 功能描述:IC SWITCH SPST 8SOIC RoHS:否 类别:集成电路 (IC) >> 接口 - 模拟开关，多路复用器，多路分解器 系列:- 标准包装:48 系列:- 功能:开关 电路:4 x SPST - NO 导通状态电阻:100 欧姆 电压电源:单/双电源 电压 - 电源，单路/双路(±):2 V ~ 12 V，±2 V ~ 6 V 电流 - 电源:50nA 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:16-SOIC（0.154"，3.90mm 宽） 供应商设备封装:16-SOIC 包装:管件 |
| ISL43110IB-T | 功能描述:IC SWITCH SPST 8SOIC RoHS:否 类别:集成电路 (IC) >> 接口 - 模拟开关，多路复用器，多路分解器 系列:- 标准包装:48 系列:- 功能:开关 电路:4 x SPST - NO 导通状态电阻:100 欧姆 电压电源:单/双电源 电压 - 电源，单路/双路(±):2 V ~ 12 V，±2 V ~ 6 V 电流 - 电源:50nA 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:16-SOIC（0.154"，3.90mm 宽） 供应商设备封装:16-SOIC 包装:管件 |
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