Electronic Components Datasheet Search
  English  ▼

Delete All
ON OFF
ALLDATASHEET.COM

X  

Preview PDF Download HTML

LM2903 Datasheet(PDF) 9 Page - 3PEAK INC.

Part No. LM2903
Description  36V Low Power Dual/Quad Differential Comparators
Download  12 Pages
Scroll/Zoom Zoom In 100% Zoom Out
Maker  3PEAK [3PEAK INC.]
Homepage  http://www.3peakic.com/
Logo 

LM2903 Datasheet(HTML) 9 Page - 3PEAK INC.

 
Zoom Inzoom in Zoom Outzoom out
 9 / 12 page
background image
9
LM2903/LM2901
36V Low Power Dual/Quad Differential Comparators
www.3peakic.com.cn
Rev. B
4. Solder the device directly to the PCB rather than using a socket.
5. For slow-moving input signals, take care to prevent parasitic feedback. A small capacitor (1000 pF or less)
placed between the inputs can help eliminate oscillations in the transition region. This capacitor causes some
degradation to propagation delay when the impedance is low. The topside ground plane should be placed
between the output and inputs.
6. The ground pin ground trace should run under the device up to the bypass capacitor, thus shielding the inputs
from the outputs.
Typical Applications
IR Receiver
The LM2903/2901 is an ideal candidate to be used as an infrared receiver shown in Figure 6. The infrared photo
diode creates a current relative to the amount of infrared light present. The current creates a voltage across RD.
When this voltage level cross the voltage applied by the voltage divider to the inverting input, the output
transitions. Optional Ro provides additional hysteresis for noise immunity.
Vo
Ro
R2
VDD
R1
LM393
RD
Figure 6. IR Receiver
Relaxation Oscillator
A relaxation oscillator using LM2903/2901 is shown in Figure 7. Resistors R1 and R2 set the bias point at the
comparator's inverting input. The period of oscillator is set by the time constant of R4 and C1. The maximum
frequency is limited by the large signal propagation delay of the comparator. LM2903/2901
’s low propagation
delay guarantees the high frequency oscillation.
If the inverted input (VC1) is lower than the non-inverting input (VA), the output is high which charges C1 through R4
until VC1 is equal to VA. The value of VA at this point is
2
R
3
R
||
1
R
2
R
DD
V
A1
V
At this point the comparator switches pulling down the output to the negative rail. The value of VA at this point is
3
R
||
2
R
1
R
3
R
||
2
R
DD
V
A2
V
If R1=R2=R3, then VA1=2VDD /3, and VA2= VDD/3
The capacitor C1 now discharges through R4, and the voltage VC decreases till it is equal to VA2, at which point the
comparator switches again, bringing it back to the initial stage. The time period is equal to twice the time it takes
to discharge C1 from 2VDD/3 to VDD/3. Hence the frequency is:


Html Pages

1  2  3  4  5  6  7  8  9  10  11  12 


Datasheet Download




Link URL




Privacy Policy
ALLDATASHEET.COM
Does ALLDATASHEET help your business so far?  [ DONATE ]  

About Alldatasheet   |   Advertisement   |   Datasheet Upload   |   Contact us   |   Privacy Policy   |   Alldatasheet API   |   Link Exchange   |   Manufacturer List
All Rights Reserved© Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com
Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn