Electronic Components Datasheet Search |
|
LP2951ACM Datasheet(PDF) 4 Page - Semtech Corporation |
|
LP2951ACM Datasheet(HTML) 4 Page - Semtech Corporation |
4 / 5 page LP2951A © 1998 SEMTECH CORP. 150mA ADJUSTABLE VOLTAGE REGULATOR March 17, 1998 652 MITCHELL ROAD NEWBURY PARK CA 91320 4 PRINCIPLES OF OPERATION (LP2951 and LP2951A) (cont.) Reducing Output Noise In ultra-quiet systems, or when the LP2951(A) is being used as a reference, it may be desirable to perform additional output filtering to reduce noise. While this can be done simply using larger capacitors on the out- put, that solution tends to be bulky and expensive, and eventually, with huge capacitors (>1,000µF) may cause instability in the regulator. Generally, it is more cost- effective to let the regulator regulate output noise away. This can be done by bypassing the upper resis- tor in the feedback divider with a small capacitor to provide a more direct path for AC feedback. The size of this capacitor can be calculated from the formula: C BYPASS = where R1 is the upper resistor of the feedback divider and f corner is the frequency above which the increased AC feedback is to become active. Because the gain of the error amplifier in the LP2951(A) begins to roll off at about 300 Hz, this is generally an optimum choice for corner frequency. The reduction of the output noise will be proportional to the ratio of the two resistors in the feedback divider, and will increase 20 dB per decade at frequencies above the corner frequency chosen, up to the fre- quency where the error amplifier’s gain has rolled off to 1 ( ≈100KHz). In order to maintain regulator stability when using a noise-reducing bypass capacitor, it will also be necessary to increase the size of the output filter capacitor by the ratio 2 R 1 R 1 R + 2 R 1 R 1 R + corner 1f R 2 1 π |
Similar Part No. - LP2951ACM |
|
Similar Description - LP2951ACM |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.COM |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
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 Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |