欢迎访问ic37.com |
会员登录 免费注册
发布采购

LMC7211BIM5X 参数 Datasheet PDF下载

LMC7211BIM5X图片预览
型号: LMC7211BIM5X
PDF下载: 下载PDF文件 查看货源
内容描述: 微型CMOS比较器具有轨至轨输入和推挽输出 [Tiny CMOS Comparator with Rail-to-Rail Input and Push-Pull Output]
分类和应用: 比较器放大器放大器电路光电二极管
文件页数/大小: 13 页 / 332 K
品牌: NSC [ National Semiconductor ]
 浏览型号LMC7211BIM5X的Datasheet PDF文件第5页浏览型号LMC7211BIM5X的Datasheet PDF文件第6页浏览型号LMC7211BIM5X的Datasheet PDF文件第7页浏览型号LMC7211BIM5X的Datasheet PDF文件第8页浏览型号LMC7211BIM5X的Datasheet PDF文件第10页浏览型号LMC7211BIM5X的Datasheet PDF文件第11页浏览型号LMC7211BIM5X的Datasheet PDF文件第12页浏览型号LMC7211BIM5X的Datasheet PDF文件第13页  
current may affect accuracy during normal operation. The  
R-C time constant of RIN and the diode capacitance may  
also slow response time.  
Application Information (Continued)  
DS012337-9  
@
@
R
R
R
R
and  
F
1
F
2
FIGURE 4. Positive Feedback for Hysteresis  
DS012337-12  
FIGURE 7.  
Without Positive Feedback  
(No Hysteresis)  
7.0 Layout Considerations  
The LMC7211 is not an especially fast comparator, so high  
speed design practices are not required. The LMC7211 is  
capable of operating with very high impedance inputs, so  
precautions should be taken to reduce noise pickup with  
high impedance ( 100 kand greater) designs and in elec-  
trically noisy environments.  
Keeping high value resistors close to the LMC7211 and mini-  
mizing the size of the input nodes is a good practice. With  
multilayer designs, try to avoid long loops which could act as  
inductors (coils). Sensors which are not close to the com-  
parator may need twisted pair or shielded connections to re-  
duce noise.  
8.0 Open Drain Output, Dual Versions  
DS012337-10  
The LMC7221 is a comparator similar to the LMC7211, but  
with an open drain output which allows the output voltage to  
be different (higher or lower) than the supply voltage. The  
open drain output is like the open collector output of a logic  
gate. This makes the LMC7221 very useful for mixed voltage  
systems. Many systems will have different voltages for the  
analog and microprocessor sections. Please see the  
LMC7221 datasheet for details.  
FIGURE 5.  
With Positive Feedback  
(Hysteresis or Memory)  
The performance of the LMC7211 is available in dual de-  
vices. Please see the LMC6762 datasheet for details on a  
dual push-pull output device. For a dual device with open  
drain outputs, please see the LMC6772 datasheet.  
Rail-to-Rail Input Low Power Comparators —  
Push-Pull Output  
LMC7211  
LMC6762  
SOT23-5, SO-8  
SO-8, DIP  
Single  
Dual  
Open Drain Output  
DS012337-11  
LMC7221  
LMC6772  
SOT23-5, SO-8  
SO-8, DIP  
Single  
Dual  
FIGURE 6.  
6.0 Input Protection  
If input signals are like to exceed the common mode range of  
the LMC7211, or it is likely that signals may be present when  
power is off, damage to the LMC7211 may occur. Large  
value (100 kto M) input resistors may reduce the likeli-  
hood of damage by limiting the input currents. Since the  
LMC7211 has very low input leakage currents, the effect on  
accuracy will be small. Additional protection may require the  
use of diodes, as shown in Figure 7. Note that diode leakage  
9
www.national.com