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 50mV of either power-

supply rail with a 10k

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

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 MAX4213/MAX4218 are disabled, the amplifi-

er’s output impedance is 35k

Ω. This high resistance

and the low 2pF output capacitance make these parts

ideal in RF/video multiplexer or switch applications. For

larger arrays, pay careful attention to capacitive load-

ing. See the Output Capacitive Loading and Stability

section for more information.

Miniature, 300MHz, Single-Supply,

Rail-to-Rail Op Amps with Enable

______________________________________________________________________________________

11

Table 1. Recommended Component Values

following equation:

R

=

75

1-

75

R

TIN

G

Ω

-25

+25

-10

+10

-5

+5

-2

+2

-1

+1

49.9

10

∞

0

50

1200

GAIN (V/V)

49.9

6

49.9

—

20

500

49.9

25

∞

0

50

500

49.9

11

49.9

—

56

500

49.9

33

100

0

100

500

49.9

25

49.9

—

124

500

49.9

60

62

0

250

500

49.9

105

49.9

—

500

500

49.9

49.9

Ω)

90

300

Small-Signal -3dB Bandwidth (MHz)

56

49.9

Ω)

0

—

Ω)

COMPONENT

500

∞

Ω)

500

24

Ω)