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参数资料
| 型号： | LMS4684ITL |
| 厂商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分类： | 运动控制电子 |
| 英文描述： | 0.5 Low-Voltage, Dual SPDT Analog Switch |
| 中文描述： | DUAL 1-CHANNEL, SGL POLE DOUBLE THROW SWITCH, PBGA12 |
| 封装： | BUMP SMD, 12 PIN |
| 文件页数： | 6/10页 |
| 文件大小： | 255K |
| 代理商： | LMS4684ITL |
Application Notes
PRODUCT DESCRIPTION
The LMS4684 is a low voltage dual analog switch with
extremely low On-Resistance operating with a supply volt-
age range of 1.8V to 5.5V. National has fully characterized
the LMS4684 to operate in applications with 3V nominal
supply voltage. The LMS4684 also features fast switching
times for Turn-Off (40ns max over temp) and Turn-On (65ns
max over temp).
The switch operates asymmetrically, one terminal is normally
closed (NC) and the other terminal normally open (NO).
Both NC and NO terminals are connected to a common
terminal (COM). This configuration is ideal for applications
with asymmetric loads such as speaker handsets and inter-
nal speakers.
ANALOG SIGNAL LEVELS
The Analog signal ranges from GND to V
+
and are passed
through the switch with very little change. Each switch is
bidirectional so any pin can be an input or output.
DIGITAL CONTROL INPUTS
The IN pin can be driven to 5.5V regardless of the voltage
level of the supply pin V
+
. For example if you wanted to have
a supply of 2V you could still drive the IN digital control input
to 5V. Minimum power is lost when the IN pin, is driven
rail-to-rail.
SUPPLY VOLTAGE SEQUENCING
It is good general practice to first apply the supply voltage to
a CMOS device before any other supply on other pins.This is
also true for the LMS4684 analog switch which is a CMOS
device.
However if it is necessary to have an analog signal applied
before the supply voltage is applied and the analog signal
supply is not limited to 20mA max, a diode connected be-
tween the supply voltage and the V
+
pin as shown in the
figure below will supply adequate input protection. This will
limit the max analog voltage to a diode drop below V
+
. This
diode D1 will also provide protection against some overvolt-
age situations.
PCB LAYOUT
Both the LLP and micro SMD packages offer enhanced
board real estate savings because of their tiny footprints.
These tiny packages are capable of supporting up to an
absolute maximum of 400mA of continuous current because
of the advanced thermal handling capabilities.
The LLP package has the exposed die attach pad internally
connected to the internal circuit GND. When this pad is
soldered to copper on the PCB board according to Applica-
tion Note AN-1187 the full thermal capability of the LLP
package can be achieved without additional bulky heat sinks
to dissipate the heat generated. The micro SMD package
has a similar capability to help dissipate heat generated
through Bumps B2 and C2 which are not electrically con-
nected. To enhance heat dissipation of the micro SMD pack-
age B2 and C2 could be connected to the GND pin and
through copper traces on the board.
Please see Application Note AN-1112 for micro SMD pack-
age considerations.
20077519
FIGURE 1. Overvoltage Protection Circuitry
L
www.national.com
6
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LMS4684ITL/NOPB | 功能描述:模拟开关 IC RoHS:否 制造商:Texas Instruments 开关数量:2 开关配置:SPDT 开启电阻（最大值）:0.1 Ohms 切换电压（最大）: 开启时间（最大值）: 关闭时间（最大值）: 工作电源电压:2.7 V to 4.5 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:DSBGA-16 |
| LMS4684ITLX | 制造商:Texas Instruments 功能描述:Analog Switch Dual SPDT 12-Pin uSMD T/R |
| LMS4684ITLX/NOPB | 功能描述:模拟开关 IC RoHS:否 制造商:Texas Instruments 开关数量:2 开关配置:SPDT 开启电阻（最大值）:0.1 Ohms 切换电压（最大）: 开启时间（最大值）: 关闭时间（最大值）: 工作电源电压:2.7 V to 4.5 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:DSBGA-16 |
| LMS4684LD | 功能描述:模拟开关 IC RoHS:否 制造商:Texas Instruments 开关数量:2 开关配置:SPDT 开启电阻（最大值）:0.1 Ohms 切换电压（最大）: 开启时间（最大值）: 关闭时间（最大值）: 工作电源电压:2.7 V to 4.5 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:DSBGA-16 |
| LMS4684LD/NOPB | 功能描述:模拟开关 IC RoHS:否 制造商:Texas Instruments 开关数量:2 开关配置:SPDT 开启电阻（最大值）:0.1 Ohms 切换电压（最大）: 开启时间（最大值）: 关闭时间（最大值）: 工作电源电压:2.7 V to 4.5 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:DSBGA-16 |
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