50 MHz to 2 GHz

Quadrature Demodulator

ADL5387

Rev. 0

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FEATURES

Operating RF frequency

50 MHz to 2 GHz

100 MHz to 4 GHz

Input IP3: 31 dBm @ 900 MHz

Input IP2: 62 dBm @ 900 MHz

Input P1dB: 13 dBm @ 900 MHz

Noise figure (NF)

12.0 dB @ 140 MHz

14.7 dB @ 900 MHz

Voltage conversion gain > 4 dB

Quadrature demodulation accuracy

Phase accuracy ~0.4°

Amplitude balance ~0.05 dB

Demodulation bandwidth ~240 MHz

Baseband I/Q drive 2 V p-p into 200 Ω

Single 5 V supply

APPLICATIONS

QAM/QPSK RF/IF demodulators

W-CDMA/CDMA/CDMA2000/GSM

Microwave point-to-(multi)point radios

Broadband wireless and WiMAX

Broadband CATVs

FUNCTIONAL BLOCK DIAGRAM

DIVIDE-BY-2

PHASE SPLITTER

1

24

CMRF CMRF RFIP RFIN CMRF VPX

CML

VPA

COM

BIAS

VPL

VPL

VPL

VPB

VPB

QHI

QLO

IHI

ILO

LOIP LOIN CML

CML COM

23

22

21

20

19

78

9

10

11

12

2

3

4

5

6

18

17

16

15

14

13

Figure 1.

GENERAL DESCRIPTION

The ADL5387 is a broadband quadrature I/Q demodulator that

covers an RF/IF input frequency range from 50 MHz to 2 GHz.

With a NF = 13.2 dB, IP1dB = 12.7 dBm, and IIP3 = 32 dBm @

450 MHz, the ADL5387 demodulator offers outstanding dynamic

range suitable for the demanding infrastructure direct-conversion

requirements. The differential RF/IF inputs provide a well-

behaved broadband input impedance of 50 Ω and are best

driven from a 1:1 balun for optimum performance.

Ultrabroadband operation is achieved with a divide-by-2 method

for local oscillator (LO) quadrature generation. Over a wide

range of LO levels, excellent demodulation accuracy is

achieved with amplitude and phase balances ~0.05 dB and

~0.4°, respectively. The demodulated in-phase (I) and

quadrature (Q) differential outputs are fully buffered and

provide a voltage conversion gain of >4 dB. The buffered

baseband outputs are capable of driving a 2 V p-p differential

signal into 200 Ω.

The fully balanced design minimizes effects from second-order

distortion. The leakage from the LO port to the RF port is

<−70 dBc. Differential dc-offsets at the I and Q outputs are

<10 mV. Both of these factors contribute to the excellent IIP2

specifications > 60 dBm.

The ADL5387 operates off a single 4.75 V to 5.25 V supply. The

supply current is adjustable with an external resistor from the

BIAS pin to ground.

The ADL5387 is fabricated using the Analog Devices, Inc.

advanced silicon-germanium bipolar process and is available in

a 24-lead exposed paddle LFCSP.