350MHz/250MHz, 2-Channel

Video Multiplexer-Amplifiers

12

______________________________________________________________________________________

Table 2. MAX4258/MAX4259 Bandwidth

and Gain vs. Gain-Setting Resistors

DC Errors and Noise

The MAX4158/MAX4159/MAX4258/MAX4259 output

the following equation:

where:

= input offset voltage (in volts)

= input bias current (in amps)

= feedback input bias current (in amps)

= gain-setting resistor (in ohms)

= feedback resistor (in ohms)

= source resistor (in ohms)

The following equation represents output noise density:

where:

The MAX4158/MAX4159/MAX4258/MAX4259 have a

very low, 2nV/

√Hz noise voltage. The current noise at

√Hz, and the current noise at the

√Hz.

An example of DC-error calculations, using the

MAX4258 typical data and the typical operating circuit

gives:

Calculating total output noise in a similar manner yields

the following:

With a 200MHz system bandwidth, this calculates to

sigma calculation).

Video Line Driver

The MAX4158/MAX4159/MAX4258/MAX4259 are opti-

mized to drive coaxial transmission lines when the

cable is terminated at both ends (Figure 3). Cable fre-

quency response may cause variations in the flatness

of the signal.

en OUT = 1 + 1

en OUT = 1.9nV/ Hz

( )

( )

(

)



















 +



















 +









−

−

−

x

x

x

x

x

x

2

10

50

2

22

10

255

2

2

10

2

1

12

12

9

e OUT = 1+R /R

n

F

G

( ) (

)

[

(

)









+

[ ]

( )

||

x

i

x R

i

x R

R

e

n

S

n FB

F

G

n

2

2

2

MAX4158

MAX4159

MAX4258

MAX4259

FB

IN_

OUT

5

14

195

92

90

14

-3dB BW

(MHz)

0.1dB BW

(MHz)

45

180

250

130

510

20

(

Ω)

(

Ω)

10

20

180

2

6

GAIN

510

(V/V)

(dB)

Figure 2. Output Offset Voltage