_______________Detailed Description

The MAX4100/MAX4101 are low-power, high-bandwidth

operational amplifiers optimized for driving back-termi-

nated cables in composite video, RGB, and RF systems.

The MAX4100 is unity-gain stable, and the MAX4101 is

optimized for closed-loop gains greater than or equal to

max) supply current, both devices can drive 50

Ω back-

terminated cables to ±3.1V minimum.

The MAX4100 features a bandwidth in excess of 500MHz

and a 0.1dB gain flatness of 65MHz. It offers differential

gain and phase errors of 0.06%/0.04°, respectively. The

MAX4101 features a -3dB bandwidth of 200MHz, a 0.1dB

bandwidth of 50MHz, and 0.07%/0.04° differential gain

and phase.

Available in small 8-pin SO and µMAX packages, these

ICs are ideally suited for use in portable systems (in

RGB, broadcast, or consumer video applications) that

benefit from low power consumption.

__________Applications Information

Layout and Power-Supply Bypassing

The MAX4100/MAX4101 have an RF bandwidth and,

consequently, require careful board layout. Depending

on the size of the PC board used and the frequency of

operation, it may be desirable to use constant-imped-

ance microstrip or stripline techniques.

To realize the full AC performance of this high-speed

amplifier, pay careful attention to power-supply bypass-

ing and board layout. The PC board should have at

least two layers: a signal and power layer on one side,

and a large, low-impedance ground plane on the other

side. The ground plane should be as free of voids as

possible. With multilayer boards, locate the ground

plane on a layer that incorporates no signal or power

traces.

Regardless of whether a constant-impedance board is

used, it is best to observe the following guidelines

when designing the board. Wire-wrap boards are much

too inductive, and breadboards are much too capaci-

tive; neither should be used. IC sockets increase para-

sitic capacitance and inductance, and should not be

used. In general, surface-mount components give bet-

ter high-frequency performance than through-hole

components. They have shorter leads and lower para-

sitic reactances. Keep lines as short and as straight as

possible. Do not make 90° turns; round all corners.

High-frequency bypassing techniques must be observed

to maintain the amplifier accuracy. The bypass capaci-

tors should include a 1000pF ceramic capacitor between

each supply pin and the ground plane, located as close

to the package as possible. Next, place a 0.01µF to

0.1µF ceramic capacitor in parallel with each 1000pF

capacitor, and as close to each as possible. Then place

a 10µF to 15µF low-ESR tantalum at the point of entry (to

the PC board) of the power-supply pins. The power-sup-

ply trace should lead directly from the tantalum capacitor

tance, keep PC traces short and use surface-mount

components.

500MHz, Low-Power Op Amps

8

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MAX4100

MAX4101

MAX4100

MAX4101

MAX4100

MAX4101

MAX4100

MAX4101

Figure 1b. Noninverting Gain Configuration

MAX4100

MAX4101

24

Ω

MAX4100

MAX4101

Figure 1c. MAX4100 Unity-Gain Buffer Configuration

Figure 1a. Inverting Gain Configuration