MIC2950-05BZ 데이터 시트보기 (PDF) - Micrel

부품명

상세내역

일치하는 목록

MIC2950-05BZ

150mA Low-Dropout Voltage Regulator

Micrel 

Micrel, Inc.

Reducing Output Noise

In some applications it may be advantageous to reduce

the AC noise present at the output. One method is to

reduce the regulator bandwidth by increasing the size of

the output capacitor. This is the only method by which

noise can be reduced on the 3 lead MIC2950 and is

relatively inefficient, as increasing the capacitor from 1µF

to 220µF only decreases the noise from 430µV to 160µV

rms for a 100kHz bandwidth at 5V output.

Noise can be reduced fourfold by a bypass capacitor

across R1, since it reduces the high frequency gain from 4

to unity. Pick:

CBYPASS

≅

1

2πR1 • 200Hz

or about 0.01µF. When doing this, the output capacitor

must be increased to 3.3µF to maintain stability. These

changes reduce the output noise from 430µV to

100µVrms for a100kHz bandwidth at 5V output. With the

bypass capacitor added, noise no longer scales with

output voltage so that improvements are more dramatic at

higher output voltages.

MIC2950/2951

Figure 1. ERROR Output Timing

Figure 2. Adjustable Regulator

February 2010

12

M9999-021610

Share Link: