MC33178 查看數據表（PDF） - ON Semiconductor

零件编号

产品描述 (功能)

比赛名单

MC33178

Low Power, Low Noise Operational Amplifiers

ON Semiconductor 

MC33178, MC33179

If a high source of resistance is used (R1 > 1.0 kW), a

compensation capacitor equal to or greater than the input

capacitance of the op amp (10 pF) placed across the

feedback resistor (see Figure 35) can be used to neutralize

that pole and prevent outer loop oscillation. Since the closed

loop transient response will be a function of that

capacitance, it is important to choose the optimum value for

that capacitor. This can be determined by the following

Equation:

CC + (1 ) [R1ńR2])2 CL (ZOńR2)

(1)

where: ZO is the output impedance of the op amp.

For moderately high capacitive loads (500 pF < CL

< 1500 pF) the addition of a compensation resistor on the

order of 20 W between the output and the feedback loop will

help to decrease miller loop oscillation (see Figure 36). For

high capacitive loads (CL > 1500 pF), a combined

compensation scheme should be used (see Figure 37). Both

the compensation resistor and the compensation capacitor

affect the transient response and can be calculated for

optimum performance. The value of CC can be calculated

using Equation 1. The Equation to calculate RC is as follows:

RC + ZO R1ńR2

(2)

R2

CC

R2

−

+

R1

ZL

−

RC

R1

+

CL

Figure 35. Compensation for

High Source Impedance

Figure 36. Compensation Circuit for

Moderate Capacitive Loads

R2

CC

−

R1

+

RC

CL

Figure 37. Compensation Circuit for

High Capacitive Loads

http://onsemi.com

12

Share Link: