参数资料
| 型号： | ISL4238EIR-T |
| 厂商： | Intersil |
| 文件页数： | 2/17页 |
| 文件大小： | 0K |
| 描述： | IC 5DRVR/3RCVR RS232 3V 32-QFN |
| 标准包装： | 6,000 |
| 类型： | 收发器 |
| 驱动器/接收器数： | 5/3 |
| 规程： | RS232 |
| 电源电压： | 2.7 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： | 带卷 (TR) |
10
FN8038.5
May 13, 2010
Power-down Functionality
The already low current requirement drops significantly
when the device enters power-down mode. In power-down,
supply current drops to 10nA, because the on-chip charge
pump turns off (V+ collapses to VCC, V- collapses to GND),
and the transmitter outputs tristate. Inverting receiver
outputs disable only in manual power-down; refer to Table 2
for details. This micro-power mode makes these devices
ideal for battery powered and portable applications.
Software Controlled (Manual) Power-down
These devices allow the user to force the IC into the low
power, standby state, and utilize a two pin approach where
the FORCEON and FORCEOFF inputs determine the IC’s
mode. For always enabled operation, FORCEON and
FORCEOFF are both strapped high. To switch between
active and power-down modes, under logic or software
control, only the FORCEOFF input need be driven. The
FORCEON state isn’t critical, as FORCEOFF dominates
over FORCEON. Nevertheless, if strictly manual control over
power-down is desired, the user must strap FORCEON high
to disable the enhanced automatic power-down circuitry.
ISL4238E, ISL4244E, ISL4245 inverting (standard) receiver
outputs also disable when the device is in manual power-
down, thereby eliminating the possible current path through
a shutdown peripheral’s input protection diode (see Figures
Connecting FORCEOFF and FORCEON together disables
the enhanced automatic power-down feature, enabling them
to function as a manual SHUTDOWN input (see Figure 4).
With any of the previous mentioned control schemes, the
time required to exit power-down, and resume transmission
is only 100s.
When using both manual and enhanced automatic power-
down (FORCEON = 0), the ISL4238E, ISL4244E, ISL4245
won’t power up from manual power-down until both
FORCEOFF and FORCEON are driven high, or until a
transition occurs on a receiver or transmitter input. Figure 5
illustrates a circuit for ensuring that the ISL4238E,
ISL4244E, ISL4245 powers up as soon as FORCEOFF
switches high. The rising edge of the Master Power-down
signal forces the device to power up, and the ISL4238E,
ISL4244E, ISL4245 returns to enhanced automatic power-
down mode an RC time constant after this rising edge. The
time constant isn’t critical, because the ISL4238E,
ISL4244E, ISL4245 remains powered up for 30s after the
FORCEON falling edge, even if there are no signal
transitions. This gives slow-to-wake systems (e.g., a mouse)
plenty of time to start transmitting, and as long as it starts
transmitting within 30s both systems remain enabled.
INVALID Output
The INVALID output always indicates (see Table 2) whether or
not 30s have elapsed with invalid RS-232 signals (see Figures
an easy way to determine when the interface block should
power down. Invalid receiver levels occur whenever the driving
peripheral’s outputs are shut off (powered down) or when the
RS-232 interface cable is disconnected. In the case of a
disconnected interface cable where all the receiver inputs are
FIGURE 3. DISABLED RECEIVERS PREVENT POWER DRAIN
ISL4238E
TRANSITION
RX
TX
ROUTB
ROUT
T1IN
FORCEOFF = GND
VCC
TO
RIN
T1OUT
VOUT = HI-Z
POWERED
DETECTOR
DOWN
UART
WAKE-UP
LOGIC
ISL4244E
ISL4245
FIGURE 4. CONNECTIONS FOR MANUAL POWER-DOWN
WHEN NO VALID RECEIVER SIGNALS ARE
PRESENT
PWR
FORCEOFF
INVALID
CPU
I/O
FORCEON
ISL4238E
MGT
LOGIC
UART
ISL4244E
ISL4245
FIGURE 5. CIRCUIT TO ENSURE IMMEDIATE POWER UP
WHEN EXITING FORCED POWER-DOWN
FORCEOFF
FORCEON
POWER
MASTER POWER-DOWN LINE
1M
Ω
0.1F
MANAGEMENT
UNIT
ISL4238E, ISL4244E, ISL4245
ISL4238E, ISL4244E, ISL4245E
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相关代理商/技术参数 |
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| ISL4238EIRZ | 功能描述:IC 5DRVR/3RCVR RS232 3V 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:2,500 系列:- 类型:发射器 驱动器/接收器数:4/0 规程:RS422，RS485 电源电压:4.75 V ~ 5.25 V 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:带卷 (TR) |
| ISL4238EIRZ-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:2,500 系列:- 类型:发射器 驱动器/接收器数:4/0 规程:RS422，RS485 电源电压:4.75 V ~ 5.25 V 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:带卷 (TR) |
| ISL4241E | 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:QFN Packaged, +/-15kV ESD Protected, +2.7V to +5.5V, 10Nanoamp, 250kbps, RS-232 Transmitters/Receivers |
| ISL4241EIR | 功能描述:IC 3DRVR/5RCVR RS232 3V 32-QFN RoHS:否 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:25 系列:- 类型:收发器 驱动器/接收器数:2/2 规程:RS232 电源电压:4.5 V ~ 5.5 V 安装类型:通孔 封装/外壳:16-DIP（0.300"，7.62mm） 供应商设备封装:16-PDIP 包装:管件 |
| ISL4241EIR-T | 功能描述:IC 3DRVR/5RCVR RS232 3V 32-QFN RoHS:否 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:25 系列:- 类型:收发器 驱动器/接收器数:2/2 规程:RS232 电源电压:4.5 V ~ 5.5 V 安装类型:通孔 封装/外壳:16-DIP（0.300"，7.62mm） 供应商设备封装:16-PDIP 包装:管件 |
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