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MAX2411AEVKIT

MAX2411A Evaluation Kit

Maxim Integrated 

MAX2411A Evaluation Kit

3) Connect one RF signal generator (with the output

disabled) to the LO SMA connector. Set the fre-

quency to 1.5GHz and the output power to -10dBm.

This is the LO signal.

4) Connect the other RF signal generator (with the out-

put disabled) to the IF SMA connector. Set the gen-

erator to a frequency of 400MHz and a power level

of -32dBm. This is the IF input signal.

5) Connect the TXMXOUT SMA connector to the spec-

trum analyzer. Configure the analyzer for a center

frequency of 1.9GHz, a reference level of 0dBm,

and 200MHz total span.

6) Turn on the DC supply, LO signal generator, and IF

input signal generator.

7) The supply current should typically read 30mA. The

spectrum analyzer should show a 1.9GHz signal,

indicating a conversion gain of typically 8.5dB after

accounting for cable and balun losses. The balun

loss is typically 1dB at 400MHz.

8) To observe the remainder of the TX mixer output

spectrum, increase the span on the spectrum ana-

lyzer from 200MHz to 2GHz.

_______________ Detailed Description

The MAX2411A EV kit circuitry is described in this section.

For more detailed information about the operation of

the device itself, please consult the MAX2411A data sheet.

Bidirectional IF Port

The MAX2411A has a unique differential, bidirectional

IF port, allowing the sharing of TX and RX IF filters. To

evaluate the part with the EV kit, a balun is used to con-

vert the single-ended IF input or output at the SMA con-

nector to a differential signal across the IF and IF pins.

In a typical application, a differential filter would be

used, and the filter would connect to a compatible IF

part, such as the MAX2511 or MAX2510.

At the IF and IF pins, inductors L3, L4, L11, and L12

provide a matching network for TX and RX mode, as

well as providing DC bias in RX mode. Capacitors C12

and C13 provide DC blocking to the balun. An extra

component footprint, R4, is provided to resistively ter-

minate this IF port. R4 can also be used for other

experimentation. The balun, L5, provides 4:1 imped-

ance transformation and differential to single-ended

conversion. The other side of the balun is connected to

the IF SMA connector. Component footprints R5, R6,

and R7 are provided for experimentation.

Receiver

This section describes the LNA and receive mixer sec-

tions of the MAX2411A EV kit.

Low-Noise Amplifier (LNA)

The LNA circuitry consists of two DC blocking capaci-

tors, one at the input (C7) and one at the output (C17).

A shunt capacitor, C21, is used as a simple input

matching network.

RX Mixer Input

The receive mixer's input, RXMXIN, requires a simple

matching network. C16 provides DC blocking, and L8

is used to match the input pin to 50Ω. Component foot-

print C22 is available for additional matching network

prototyping. The output of the receive mixer appears at

the bidirectional IF port in receive mode.

Transmitter

This section describes the PA driver and transmit mixer

sections of the MAX2411A EV kit.

PA Driver Amplifier

The PA driver amplifier input is internally matched to

50Ω for 1.9GHz operation; capacitor C11 is necessary

for DC blocking. The gain of the PA driver is adjustable

by applying a voltage on the middle pin of the VGC

jumper, which is connected through a 1kΩ resistor (R3)

to the GC pin on the MAX2411A. Alternatively, by

inserting a shunt, it is possible to set this voltage to

ground or VCC. The position labeled "Logic 0" is con-

nected to ground, and the "Logic 1" position is connected

to VCC.

TX Mixer Output

The transmit mixer output appears on the TXMXOUT

pin, which requires a pull-up inductor to VCC (L2) and a

matching network to a 50Ω load impedance consisting

of inductors L2 and L13. C19 provides DC blocking.

Local Oscillator (LO)

The EV kit’s LO input has a DC blocking capacitor

(C20). No other circuitry is required. For more informa-

tion on the LO port, including the optional use of a dif-

ferential LO source, consult the MAX2411A data sheet.

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