Maxim recommends using microstrip and stripline tech-

niques to obtain full bandwidth. To ensure that the PC

board does not degrade the amplifier’s performance,

design it for a frequency greater than 1GHz. Pay care-

ful attention to inputs and outputs to avoid large para-

sitic capacitance. Whether or not you use a constant-

impedance board, observe the following guidelines

when designing the board:

• Don’t use wire-wrap boards because they are too

inductive.

• Don’t use IC sockets because 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 possi-

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

Rail-to-Rail Outputs,

Ground-Sensing Input

The input common-mode range extends from

mode rejection. Beyond this range, the amplifier output

is a nonlinear function of the input, but does not under-

go phase reversal or latchup.

The output swings to within 60mV of either power-

supply rail with a 2k

Ω load. The input ground-sensing

and the rail-to-rail output substantially increase the

dynamic range. With a symmetric input in a single +5V

application, the input can swing 2.95Vp-p, and the out-

put can swing 4.9Vp-p with minimal distortion.

Enable Input and Disabled Output

The enable feature (EN_) allows the amplifier to be

placed in a low-power, high-output-impedance state.

tor connected as shown in Figure 3 prevents the rise in

the logic-low input current. This resistor provides a

When the MAX4018 is disabled, the amplifier’s output

impedance is 35k

Ω. This high resistance and the low

2pF output capacitance make this part ideal in

RF/video multiplexer or switch applications. For larger

arrays, pay careful attention to capacitive loading. See

the

Output Capacitive Loading and Stability section for

more information.

Low-Cost, High-Speed, SOT23, Single-Supply

Op Amps with Rail-to-Rail Outputs

______________________________________________________________________________________

11

24

500

∞

500

COMPONENT

—

0

49.9

56

Small-Signal -3dB Bandwidth (MHz)

200

90

49.9

49.9

Table 1. Recommended Component Values

following equation:

500

500

—

49.9

105

49.9

500

250

0

62

60

49.9

500

124

—

49.9

25

49.9

500

100

0

100

33

49.9

500

56

—

49.9

11

49.9

500

50

0

∞

25

49.9

500

20

—

49.9

6

49.9

GAIN (V/V)

1200

50

0

∞

10

49.9

+1

-1

+2

-2

+5

-5

+10

-10

+25

-25

R

=

75

1-

75

R

TIN

G

Ω