参数资料
| 型号： | ISL4244EIR |
| 厂商： | Intersil |
| 文件页数： | 4/17页 |
| 文件大小： | 0K |
| 描述： | IC 3DRVR/5RCVR RS232 3V 32-QFN |
| 标准包装： | 60 |
| 类型： | 收发器 |
| 驱动器/接收器数： | 3/5 |
| 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： | 管件 |
12
FN8038.5
May 13, 2010
Hybrid Automatic Power-down 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 power-down 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
ISL4238E, ISL4244E, ISL4245 remains powered down until the
cable is reconnected (INVALID = FORCEOFF = 1) and a
transition occurs on a receiver or transmitter input (see Figure
7). For immediate power up when the cable is reattached,
connect FORCEON to FORCEOFF through a network similar
to that shown in Figure 5.
Capacitor Selection
The ISL4238E charge pumps require 0.1
μF, or greater,
capacitors for 3.3V (5% tolerance) operation. For other
supply voltages refer to Table 3 for capacitor values. Do not
use values smaller than those listed in Table 3.
The ISL4244E/45E charge pumps require 0.1F capacitors
for proper operation. Increasing the capacitor values (by a
factor of 2) reduces ripple on the transmitter outputs and
slightly reduces power consumption. C2, C3, and C4 can be
increased without increasing C1’s value, however, do not
increase C1 without also increasing C2, C3, and C4 to
maintain the proper ratios (C1 to the other capacitors).
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 0.1F 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
Power-down
Figure 10 shows the response of two transmitter outputs
when exiting power-down 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.
Operation Down to 2.7V
ISL4238E, ISL4244E, ISL4245 transmitter outputs meet
RS-562 levels (±3.7V), at the full data rate, with VCC as low
as 2.7V. RS-562 levels typically ensure interoperability with
RS-232 devices.
TABLE 3. REQUIRED CAPACITOR VALUES (ISL4238E)
VCC (V)
C1 (F)
C2, C3, C4 (F)
3.0 to 3.6 (3.3V ±10%)
0.22
3.15 to 3.6 (3.3V ±5%)
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 9. ENHANCED AUTOMATIC POWER-DOWN AND INVALID TIMING DIAGRAMS
OUTPUT
TRANSMITTER
INPUTS
tWU
tAUTOPWDN
tWU
INVALID
REGION
}
ISL4238E, ISL4244E, ISL4245E
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| ISL4244EIR-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 |
| ISL4244EIRZ | 功能描述:IC TXRX RS232 2.7-5.5V 32QFN 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) |
| ISL4244EIRZ-T | 功能描述:IC 3DRVR/5RCVR 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) |
| ISL4245E | 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/ 1Mbps, RS-232 Transceivers with Enhanced Automatic Powerdown |
| ISL4245EIR | 功能描述:IC LINE TRANSCVR CMOS 3-DRVR RoHS:否 类别:集成电路 (IC) >> 接口 - 驱动器，接收器，收发器 系列:- 标准包装:1,000 系列:- 类型:收发器 驱动器/接收器数:2/2 规程:RS232 电源电压:3 V ~ 5.5 V 安装类型:表面贴装 封装/外壳:16-SOIC（0.295"，7.50mm 宽） 供应商设备封装:16-SOIC 包装:带卷 (TR) |
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