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

and 150nA Shutdown Current

10

______________________________________________________________________________________

0.1

1

10

100

FREQUENCY RESPONSE

FREQUENCY (MHz)

0

-60

-50

-40

-30

-20

-10

Figure 5. Frequency Response for R1 = R2 = 150

Ω

R2

150

Ω

R1

150

Ω

C1

120pF

C2

120pF

L1

4.7

C3

6.8pF

C4

0.1

R3

75

Ω

C5

22

C6

22

C7

1

IN

OUT

GND

FB

SHDN

VIDEO

CURRENT

DAC

49.9

Ω

3-POLE RECONSTRUCTION LPF

MAX4090

Figure 6. Sag Correction Configuration

Layout and Power-Supply Bypassing

The MAX4090 operates from single 2.7V to 5.5V sup-

ply. Bypass the supply with a 0.1µF capacitor as close

to the pin as possible. Maxim recommends using

microstrip and stripline techniques to obtain full band-

width. To ensure that the PC board does not degrade

the device’s performance, design it for a frequency

greater than 1GHz. Pay careful attention to inputs and

outputs to avoid large parasitic capacitance. Whether

or not you use a constant-impedance board, observe

the following design guidelines:

• Do not use wire-wrap boards; they are too inductive.

• Do not use IC sockets; they increase parasitic

capacitance and inductance.

• Use surface-mount instead of through-hole compo-

nents for better, high-frequency performance.

• Use a PC board with at least two layers; it should be

as free from voids as possible.

• Keep signal lines as short and as straight as possible.

Do not make 90° turns; round all corners.