IF Digitally Controlled Variable-Gain Amplifier

8

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Fixed-Gain Amplifier

The MAX2027 integrates a fixed-gain amplifier in a neg-

ative feedback topology. This fixed-gain amplifier is

optimized for a frequency range of operation from

50MHz to 400MHz with a high-output third-order inter-

cept point (OIP3). The bias current is chosen to opti-

current consumption is 60mA while exhibiting a typical

Choke Inductor

The fixed-gain amplifier output port requires an external

(pin 14). At the output, connect a 680nH choke inductor

current to the amplifier.

Layout Considerations

A properly designed PC board is an essential part of

any RF/microwave circuit. Keep RF signal lines as short

as possible to reduce losses, radiation, and induc-

tance. For the best performance, route the ground pin

traces directly to the exposed pad under the package.

The PC board exposed pad must be connected to the

ground plane of the PC board. It is suggested that multi-

ple vias be used to connect this pad to the lower level

ground planes. This method provides a good RF/thermal

conduction path for the device. Solder the exposed pad

on the bottom of the device package to the PC board.

The MAX2027 Evaluation Kit can be used as a refer-

ence for board layout. Gerber files are available upon

request at www.maxim-ic.com.

Power-Supply Bypassing

Proper voltage-supply bypassing is essential for high-

0.1µF and 100pF capacitor. Connect the 100pF capacitor

Exposed Pad RF/Thermal Considerations

The exposed paddle (EP) of the MAX2027’s 20-pin

TSSOP-EP package provides a low thermal-resistance

path to the die. It is important that the PC board on

20

19

18

17

16

15

14

13

1

2

3

4

5

6

7

8

RF IN

B2

B3

B4

12

11

9

10

RF OUT

B0

B1

MAX2027

ATTENUATION

LOGIC

CONTROL

AMP

BIAS

CONTROL

INPUTS

*OPTIONAL COMPONENTS: USE TO IMPROVE HIGHER FREQUENCY MATCHING

EXPOSED

PADDLE

Figure 1. Typical Application Circuit