MAX2700 View Datasheet(PDF) - Maxim Integrated

Part Name

Description

Manufacturer

MAX2700

1.8GHz to 2.5GHz Direct Downconversion Receivers

Maxim Integrated 

1.8GHz to 2.5GHz Direct Downconversion

Receivers

Functional Diagram

IOUT2

IIN2-

IIN2+

IOUT1

IIN1-

IIN1+

MIX_I

AGC2 I_CHANNEL

OFFSET CORRECTION

LOOP

AGC1 I_CHANNEL

AGC2 Q_CHANNEL

OFFSET CORRECTION

LOOP

AGC1 Q_CHANNEL

OFFSET CORRECTION

LOOP

I_CHANNEL

OFFSET CORRECTION

LOOP

AMP

DOUBLE BALANCED

MIXER

Q_CHANNEL

AMP

POLYPHASE RC

QUADRATURE

GENERATOR

MULTIPLEXER

DOUBLER

X2

LD GENERATOR

BIAS

BLOCK

MST

SHDN

BIAS BIAS HIGH-GAIN AMP

LNA BLOCK

LOW-GAIN AMP

QOUT2

QIN2-

QIN2+

QOUT1

QIN1-

QIN1+

RFIN-

RFIN+

MIX_Q

X2_EN

LO

LNAOUT

SHDN

LNAIN GAIN_SET

very low output impedance (<2Ω). The smallest load

that should be used is 600Ω. At the output of the I/Q

mixers’ buffers, baseband lowpass filters should be

used to provide adjacent and alternate channel selectiv-

ity. This reduces the level of adjacent channel and

close-in interferers to the input of the following base-

band amplifier.

The LO signal is applied externally to the LO input port.

An LO doubler circuit doubles the LO signal frequency

before it is applied to the mixer LO port. Connect

X2_EN to ground to enable the LO doubler circuit. With

this circuit enabled, the required LO frequency is half

that of the RF carrier frequency. Connect X2_EN to VCC

to disable the frequency doubler circuit and the LO fre-

quency is the same as the RF carrier frequency. The

half LO frequency scheme results in the use of lower

frequency and lower cost VCOs. It also reduces the LO

leakage to the receiver’s input. The mixer is guaranteed

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