ADL5363-EVALZ AD [Analog Devices], ADL5363-EVALZ Datasheet - Page 17

• Manufacturer Part Number: ADL5363-EVALZ
• Description: 2300 MHz to 2900 MHz Balanced Mixer
• Manufacturer: AD [Analog Devices]

CIRCUIT DESCRIPTION
The
frequency (RF) subsystem and the local oscillator (LO) subsystem.
The combination of design, process, and packaging technology
allows the functions of these subsystems to be integrated
into a single die, using mature packaging and interconnection
technologies to provide a high performance, low cost design
with excellent electrical, mechanical, and thermal properties.
In addition, the need for external components is minimized,
optimizing cost and size.
The RF subsystem consists of an integrated, low loss RF balun,
passive MOSFET mixer, sum termination network.
The LO subsystem consists of an SPDT-terminated FET switch
and a three-stage limiting LO amplifier. The purpose of the LO
subsystem is to provide a large, fixed amplitude, balanced signal
to drive the mixer independent of the level of the LO input.
A block diagram of the device is shown in Figure 48.
COMM
COMM
NC = NO CONNECT
VPMX
RFCT
RFIN
ADL5363
1
2
3
4
5
VCMI
VLO3
20
6
consists of two primary components: the radio
Figure 48. Simplified Schematic
LGM3
IFOP
19
GENERATOR
7
BIAS
VLO2
IFON
18
8
PWDN
LOSW
ADL5363
17
9
COMM
NC
16
10
15
14
13
12
11
LOI2
VPSW
VGS1
VGS0
LOI1
Rev. 0 | Page 17 of 24
RF SUBSYSTEM
The single-ended, 50 Ω RF input is internally transformed to a
balanced signal using a low loss (<1 dB) unbalanced-to-balanced
(balun) transformer. This transformer is made possible by an
extremely low loss metal stack, which provides both excellent
balance and dc isolation for the RF port. Although the port can
be dc connected, it is recommended that a blocking capacitor be
used to avoid running excessive dc current through the part.
The RF balun can easily support an RF input frequency range
of 2300 MHz to 2900 MHz.
The resulting balanced RF signal is applied to a passive mixer
that commutates the RF input with the output of the LO subsystem.
The passive mixer is essentially a balanced, low loss switch that
adds minimum noise to the frequency translation. The only
noise contribution from the mixer is due to the resistive loss
of the switches, which is in the order of a few ohms.
As the mixer is inherently broadband and bidirectional, it
is necessary to properly terminate all the idler (M × N product)
frequencies generated by the mixing process. Terminating the
mixer avoids the generation of unwanted intermodulation
products and reduces the level of unwanted signals at the IF
output. This termination is accomplished by the addition of a
sum network between the IF output and the mixer.
The IP3 performance can be optimized by adjusting the supply
current with an external resistor. Figure 37 and 38 illustrate how
the bias resistor affects the performance with a 5 V supply.
Additionally, dc current can be saved by increasing either or
both resistors. It is permissible to reduce the dc supply voltage
to as low as 3.3 V, further reducing the dissipated power of the
part. (Note that no performance enhancement is obtained by
reducing the value of these resistors and excessive dc power
dissipation may result.)
ADL5363