MAX4090 View Datasheet(PDF) - Maxim Integrated

Part Name

Description

Manufacturer

MAX4090

3V/5V, 6dB Video Buffer with Sync-Tip Clamp and 150nA Shutdown Current

Maxim Integrated 

3V/5V, 6dB Video Buffer with Sync-Tip Clamp

and 150nA Shutdown Current

between 20Ω to 100Ω is needed to isolate the input

capacitor (C4) to the filter to prevent the oscillation

problem.

C = Cn L = LnRL

2πfCRL

2πfC

Figure 2 shows the frequency response for R1 = R2 =

150Ω. At 6MHz, the attenuation is about 1.4dB. The

attenuation at 27MHz is about 20dB. Figure 3 shows

the multiburst response for R1 = R2 = 150Ω.

3rd-Order Butterworth Lowpass Filter Realization

If more flat passband and more stopband attenuation

are needed, a 3rd-order LPF can be used. The design

procedures are similar to the 2nd-order butterworth

LPF.

Table 3 shows the normalized 3rd-order butterworth

lowpass filter with the cutoff frequency at 1 rad/s and

the stopband frequency at 3 rad/s. Table 4 shows the

appropriated L and C values for different source/load

impedance and the bench measurement values for

-3dB BW and attenuation at 27MHz. The attenuation is

over 40dB at 27MHz. At 6MHz, the attenuation is

approximately 0.6dB for R1 = R2 = 150Ω (Figure 5).

VIDEO

CURRENT

DAC

2-POLE RECONSTRUCTION LPF

L1

3.9μH

R1

150Ω

C1

150pF

R2

150Ω

Figure 1. 2nd-Order Butterworth LPF with MAX4090

RIS

49.9Ω

C4

0.1μF

VCC

VCC

IN

OUT

MAX4090

SHDN

FB

GND

VCC

C7

1μF

R3

75Ω

VOUT

FREQUENCY RESPONSE

0

-10

-20

-30

-40

-50

-60

0.1

1

10

100

FREQUENCY (MHz)

Figure 2. Frequency Response

10μs/div

Figure 3. Multiburst Response

VIN

500mV/div

VOUT

500mV/div

8 _______________________________________________________________________________________

Share Link: