Datasheet

Evaluate: MAX2900–MAX2904

used to control the power of the transmitter. Changing

the values of the resistors R

RLPF

and R

PWRSET

vary the

modulation filter characteristics and output power level,

respectively. Refer to the MAX2900–MAX2904 data

sheet for details.

Output Power Adjustment

The MAX2900–MAX2904 EV kits are tuned for specific

output powers. For example, the MAX2900 EV kit is

tuned for 23dBm at a 4.5V supply voltage. If other out-

put power levels are desired, the user must modify

some EV kit components. This section, intended as a

guide only, provides instructions for tuning the EV kits

at different power levels.

To achieve a different output power, modify R

PWRSET

(R8) first. This resistor sets the bias current, which also

controls efficiency and output power. To decrease out-

put power, increase the value of R8. For more informa-

tion, refer to the MAX2900–MAX2904 data sheet.

The output-matching network also must be changed to

appropriate output power levels. For lower power lev-

els, increase C15 and C16 capacitor values. To main-

tain the same LC filter corner frequency, change L3,

L4, C33, and C34 accordingly. To achieve optimum

performance, all component values must be tuned in

the lab. Use the EV kit schematics as a guideline.

Layout Issues

A good PC board is an essential part of an RF circuit

design. The EV kit PC board can serve as a guide for

laying out a board using the MAX2900–MAX2904. Keep

traces carrying RF signals as short as possible to mini-

mize radiation and insertion loss. Use impedance con-

trol on all RF signal traces. The V

node on the PC

board should have decoupling capacitors to the clos-

est ground. Refer to the Layout section of the

MAX2900–MAX2904 data sheet for more information.

MAX2900–MAX2904 Evaluation Kits

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