400 MHz to 6 GHz
Quadrature Demodulator
ADL5380
FEATURES
FUNCTIONAL BLOCK DIAGRAM
ENBL ADJ
Operating RF and LO frequency: 400 MHz to 6 GHz
Input IP3
ADL5380
IHI
BIAS
30 dBm @ 900 MHz
28 dBm @1900 MHz
Input IP2: >65 dBm @ 900 MHz
Input P1dB (IP1dB): 11.6 dBm @ 900 MHz
Noise figure (NF)
ILO
LOIP
10.9 dB @ 900 MHz
11.7 dB @ 1900 MHz
Voltage conversion gain: ~7 dB
Quadrature demodulation accuracy @ 900 MHz
Phase accuracy: ~0.2°
RFIN
RFIP
QUADRATURE
PHASE SPLITTER
V2I
LOIN
QHI
Amplitude balance: ~0.07 dB
Demodulation bandwidth: ~390 MHz
Baseband I/Q drive: 2 V p-p into 200 Ω
Single 5 V supply
QLO
Figure 1.
APPLICATIONS
Cellular W-CDMA/GSM/LTE
Microwave point-to-(multi)point radios
Broadband wireless and WiMAX
GENERAL DESCRIPTION
The ADL5380 is a broadband quadrature I-Q demodulator that
covers an RF/IF input frequency range from 400 MHz to 6 GHz.
With a NF = 10.9 dB, IP1dB = 11.6 dBm, and IIP3 = 29.7 dBm @
900 MHz, the ADL5380 demodulator offers outstanding dynamic
range suitable for the demanding infrastructure direct-conversion
requirements. The differential RF inputs provide a well-behaved
broadband input impedance of 50 Ω and are best driven from a
1:1 balun for optimum performance.
The fully balanced design minimizes effects from second-order
distortion. The leakage from the LO port to the RF port is
<−50 dBm. Differential dc offsets at the I and Q outputs are
typically <20 mV. Both of these factors contribute to the
excellent IIP2 specification, which is >65 dBm.
The ADL5380 operates off a single 4.75 V to 5.25 V supply. The
supply current is adjustable by placing an external resistor from
the ADJ pin to either the positive supply, VS, (to increase supply
current and improve IIP3) or to ground (which decreases supply
current at the expense of IIP3).
Excellent demodulation accuracy is achieved with amplitude
and phase balances of ~0.07 dB and ~0.2°, respectively. The
demodulated in-phase (I) and quadrature (Q) differential outputs
are fully buffered and provide a voltage conversion gain of ~7 dB.
The buffered baseband outputs are capable of driving a 2 V p-p
differential signal into 200 Ω.
The ADL5380 is fabricated using the Analog Devices, Inc.,
advanced silicon-germanium bipolar process and is available
in a 24-lead exposed paddle LFCSP.
Rev. 0
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