Adjustable, High-Linearity,

SiGe Dual-Band LNA/Mixer ICs

16

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MAX2322 Operation

The MAX2322 is a lower-cost PCS-only version that can

be installed as a drop-in replacement for the dual-band

versions. It consists of a PCS LNA, PCS mixer, pin-

selectable LO frequency doubler, and LO buffer. Logic

except the LO buffer. The LOX2 logic input controls the

LO frequency doubler. LOX2 = GND disables the dou-

activates the doubler when using a cellular-band VCO.

GAIN and LIN logic inputs control the MAX2322’s three

operational modes, as summarized in Table 2.

MAX2324 Operation

The MAX2324 is a lower-cost cellular-only version that

can be installed as a drop-in replacement for the dual-

band versions. It consists of a cellular LNA, cellular dig-

ital mixer, cellular FM mixer, and LO buffer. A SHDN

logic input turns on/off the entire IC except the LO

buffer. GAIN and LIN logic inputs control the

MAX2324’s three operational modes, as summarized in

Table 3.

MAX2327 Operation

The MAX2327 is similar to the MAX2320 except it only

features an HGLL mode, and either LO output buffer is

selectable during shutdown. It consists of PCS and cel-

lular LNAs; PCS, cellular digital, and cellular FM mixers;

and PCS and cellular LO buffers. A SHDN logic input

turns on/off the entire IC except the LO buffer. BAND

and MODE logic inputs control the MAX2327’s three

operational modes, as summarized in Table 4.

Applications Information

Cascaded LNA/Mixer Performance

The LNA and mixer design aims at optimizing cascad-

ed performance in all gain and linearity modes. In high-

gain, high-linearity mode, both the LNA and mixer have

a low noise figure, high gain, and high linearity. The

LNA has high gain to minimize the noise contribution of

the mixer, thus increasing the receiver’s sensitivity and

extra-high linearity for superior cross-modulation sup-

pression. The HGLL mode is used when the transmitter

is off and cross-modulation is not a concern. In low-

gain, high-linearity mode, the received signal is strong

enough that linearity is the primary concern. The LNA

gain is reduced for higher system linearity. Tables 5

and 6 summarize the cascaded performance.

S Parameters

The S parameters are listed in Tables 7–11. An electron-

ic copy is also available at www.maxim-ic.com

/MAX2320/S_table/.

Table 2. MAX2322 Operational Modes

Table 4. MAX2327 Operational Modes

OPERATIONAL MODE

Not used.

Digital PCS Mode. The LNA and mixer

are in HGLL mode.

FM Mode. The cellular FM mixer is

selected.

Digital Cellular Mode. The cellular digi-

tal mixer is selected.

BAND

L

L

H

H

MODE

L

H

L

H

OPERATIONAL MODE

FM Mode. The LNA is in HGLL mode.

The FM mixer and the associated LO

buffer are selected.

Low-Gain, High-Linearity (LGHL)

Cellular Mode. The LNA and digital

mixer are in LGHL mode.

High-Gain, Low-Linearity (HGLL )

Cellular Mode. The LNA and digital

mixer are in HGLL mode.

High-Gain, High-Linearity (HGHL )

Cellular Mode. The LNA and digital

mixer are in HGHL mode.

GAIN

L

L

H

H

LIN

L

H

L

H

OPERATIONAL MODE

Not used.

Low-Gain, High-Linearity (LGHL) PCS

Mode. The LNA and mixer are in LGHL

mode.

High-Gain, Low-Linearity (HGLL) PCS

Mode. The LNA and mixer are in HGLL

mode.

High-Gain, High-Linearity (HGHL) PCS

Mode. The LNA and mixer are in HGHL

mode.

GAIN

L

L

H

H

LIN

L

H

L

H

Note: L = Logic Low; H = Logic High

Note: L = Logic Low; H = Logic High

Note: L = Logic Low; H = Logic High

Table 3. MAX2324 Operational Modes