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Feedback Components (R3, R6, C3, C4, C5)

C5

+

1

2

p

R8

F

Z2

(28)

R6

+

1

2

p

C5

F

P1

(29)

R3

+

A

MID(band)

(R6

R8)

R6

) R8

(30)

C4

+

1

2

p

R3

F

Z1

(31)

C3

+

1

2

p

R3

F

P2

(32)

0dB

FZ1

Frequency (Log Scale)

FZ2

FP1

FP2

Amid−Band

FSW

TPS40040, TPS40041

SLUS700D – MARCH 2006 – REVISED DECEMBER 2007

Approximate C5 with the formula:

C5 = 560 pF (closest standard capacitor value to calculated 568 pF) and approximate R6 with the formula:

R6 = 4.75 k

Ω (closest standard resistor value to calculated 4.74 kΩ) Calculate R3 by the formula:

With AMID_BAND = 3.84, R6 = 4.75 kΩ and R8 = 20 kΩ, R3 = 14.7 kΩ (closest standard resistor value to calculated

14.7 k

Ω) Calculate C3 and C4 by the equations:

For R3 = 14.7 k

Ω, C3 = 47 pF (closest standard value to 45 pF) C4 = 1200 pF (closest standard value to 1.2 nF)

Error Amplifier straight line approximation transfer function looks like Figure 25.

Figure 25. Error Amplifier Frequency Response Straight Line Approximation

26

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Product Folder Link(s): TPS40040 TPS40041