4) Connect the other RF signal generator (with the out-
put disabled) to the IFIN SMA connector. Set the
generator to a frequency of 400MHz and a power
level of -32dBm. This is the IF 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
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 10dB after
accounting for cable losses.
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 MAX2410 EV kit circuitry is described in this sec-
tion. For more detailed information about the operation
of the device itself, please consult the MAX2410 data
sheet.
Receiver
This section describes the LNA and receive mixer sec-
tions of the MAX2410 EV kit.
Low-Noise Amplifier
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.
IF Output
The IFOUT pin of the MAX2410 is an open-collector
output that is externally biased to V
CC
by inductor L3
and matched with inductors L3 and L12. C24 provides
DC blocking. There are additional component footprints
available on the EV kit layout for designing a more com-
plex matching network: C12, C26, L5, and L9.
RX Mixer Input
The receive mixer’s input, RXMXIN, requires a simple
matching network. Capacitor C16 provides DC block-
ing, and L8 is used to match the input pin to 50Ω.
Component footprint (C22) is available for additional
matching network prototyping.
Transmitter
This section describes the PA driver and transmit mixer
sections of the MAX2410 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 V
GC
jumper, which is connected through a 1kΩ resistor (R3)
to the GC pin of the MAX2410. C8 and R3 form a filter
to reduce any noise from the V
GC
supply. Alternatively,
by inserting a shunt, it is possible to set this voltage to
ground or V
CC
. The position labeled “Logic 0” is con-
nected to ground, and the “Logic 1” position is set to
V
CC
.
IF Input
The IFIN pin of the MAX2410 is a high-impedance input
that is internally biased. Inductor L11 provides a simple
matching network. C23 is used for DC blocking. As with
the IFOUT pin above, additional component footprints
have been placed to allow further experimentation:
C14, C25, L4, L6, and L7.
TX Mixer Output
The transmit mixer output appears on the TXMXOUT
pin, which requires a pull-up inductor (L2) to V
CC
as
well as a matching network to a 50Ω load impedance
consisting of inductors L2 and L13. C19 serves as a
DC block.
Local Oscillator
The MAX2410 EV kit’s LO input only requires a DC
blocking capacitor (C20). No other circuitry is required.
For more information on the LO port, including the
optional use of a differential LO source, consult the
MAX2410 data sheet.
________________Power Management
The RXEN and TXEN jumpers on the EV kit control the
operating modes of the MAX2410. Refer to the
MAX2410 data sheet for a table of operating modes.
Series resistors R1 and R2 and capacitors C5 and C6
are included on the RXEN and TXEN inputs to provide
filtering between logic and RF circuitry.
______________________________Layout
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 MAX2410.
Each V
CC
node on the PC board should have its own
decoupling capacitor. This minimizes supply coupling
from one section of the MAX2410 to another. A star
topology for the supply layout, in which each V
CC
node
on the MAX2410 circuit has a separate connection to a
central V
CC
node, can further minimize coupling
between sections of the MAX2410 (Figure 5).
Evaluates: MAX2410
MAX2410 Evaluation Kit
_______________________________________________________________________________________ 3
