参数资料
型号: ICL3238EIA
厂商: Intersil
文件页数: 13/14页
文件大小: 0K
描述: IC 5DRVR/3RCVR RS232 3V 28-SSOP
标准包装: 47
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: 管件
8
FORCEOFF switches high. The rising edge of the Master
Powerdown signal forces the device to power up, and the
ICL3238E returns to enhanced automatic powerdown mode
an RC time constant after this rising edge. The time constant
isn’t critical, because the ICL3238E remains powered up for
30 seconds 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 30 seconds 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 6 and 8) persisting on all of the receiver inputs,
giving the user 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 floating (but pulled to GND
by the internal receiver pull down resistors), the INVALID
logic detects the invalid levels and drives the output low. The
power management logic then uses this indicator to power
down the interface block. Reconnecting the cable restores
valid levels at the receiver inputs, INVALID switches high,
and the power management logic wakes up the interface
block. INVALID can also be used to indicate the DTR or
RING INDICATOR signal, as long as the other receiver
inputs are floating, or driven to GND (as in the case of a
powered down driver).
Enhanced Automatic Powerdown
Even greater power savings is available by using this device
which features an enhanced automatic powerdown function.
When the enhanced powerdown logic determines that no
transitions have occurred on any of the transmitter nor
receiver inputs for 30 seconds, the charge pump and
transmitters powerdown, thereby reducing supply current to
10nA. The ICL3238E automatically powers back up
whenever it detects a transition on one of these inputs. This
automatic powerdown feature provides additional system
power savings without changes to the existing operating
system.
Enhanced automatic powerdown operates when the
FORCEON input is low, and the FORCEOFF input is high.
Tying FORCEON high disables automatic powerdown, but
manual powerdown is always available via the overriding
FORCEOFF input. Table 2 summarizes the enhanced
automatic powerdown functionality.
Figure 7 illustrates the enhanced powerdown control logic.
Note that once the ICL3238E enters powerdown (manually
or automatically), the 30 second timer remains timed out
(set), keeping the ICL3238E powered down until FORCEON
transitions high, or until a transition occurs on a receiver or
transmitter input.
The INVALID output signal switches low to indicate that
invalid levels have persisted on all of the receiver inputs for
more than 60s (see Figure 8), but this has no direct effect
on the state of the ICL3238E (see the next sections for
methods of utilizing INVALID to power down the device).
INVALID switches high 1s after detecting a valid RS-232
level on a receiver input. INVALID operates in all modes
(forced or automatic powerdown, or forced on), so it is also
useful for systems employing manual powerdown circuitry.
The time to recover from automatic powerdown mode is
typically 25s.
FIGURE 5. CIRCUIT TO ENSURE IMMEDIATE POWER UP
WHEN EXITING FORCED POWERDOWN
FORCEOFF
FORCEON
POWER
MASTER POWERDOWN LINE
1M
0.1F
MANAGEMENT
UNIT
ICL3238E
FIGURE 6. DEFINITION OF VALID RS-232 RECEIVER LEVELS
0.3V
-0.3V
-2.7V
2.7V
INVALID LEVEL - INVALID = 0
VALID RS-232 LEVEL - INVALID = 1
INDETERMINATE
FIGURE 7. ENHANCED AUTOMATIC POWERDOWN LOGIC
30s
TIMER
S
R
FORCEOFF
AUTOSHDN
FORCEON
R_IN
T_IN
EDGE
DETECT
EDGE
DETECT
ICL3238E
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ICL3238EIA-T 功能描述:IC 5DRVR/3RCVR RS232 3V 28-SSOP 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
ICL3238EIAZ 功能描述:RS-232接口集成电路 RS232 3V 5D/3R 15KV PWR-DWN IND 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:
ICL3238EIAZ-T 功能描述:RS-232接口集成电路 RS232 3V 5D/3R 15KV PWR-DWN IND 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:
ICL3238EIV 制造商:Rochester Electronics LLC 功能描述:RS232 3V 5D/3R 15KV E-DWN 28TSSOP IND - Bulk
ICL3238EIV-T 功能描述:IC 5DRVR/3RCVR RS232 3V 28-TSSOP 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