ADL5355-EVALZ AD [Analog Devices], ADL5355-EVALZ Datasheet - Page 17
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ADL5355-EVALZ
Manufacturer Part Number
ADL5355-EVALZ
Description
1200 MHz to 2500 MHz Balanced Mixer, LO Buffer, IF Amplifier, and RF Balun
Manufacturer
AD [Analog Devices]
Datasheet
1.ADL5355-EVALZ.pdf
(24 pages)
LO SUBSYSTEM
The LO amplifier is designed to provide a large signal level to
the mixer to obtain optimum intermodulation performance.
The resulting amplifier provides extremely high performance
centered on an operating frequency of 1700 MHz. The best
operation is achieved with either low-side LO injection for RF
signals in the 1700 MHz to 2500 MHz range or high-side injection
for RF signals in the 1200 MHz to 1700 MHz range. Operation
outside these ranges is permissible, and conversion gain is
extremely wideband, easily spanning 1200 MHz to 2500 MHz,
but intermodulation is optimal over the aforementioned ranges.
The ADL5355 has two LO inputs permitting multiple synthesizers
to be rapidly switched with extremely short switching times
(<40 ns) for frequency agile applications. The two inputs are
applied to a high isolation SPDT switch that provides a constant
input impedance, regardless of whether the port is selected, to
avoid pulling the LO sources. This multiple section switch also
ensures high isolation to the off input, minimizing any leakage
from the unwanted LO input that may result in undesired IF
responses.
The single-ended LO input is converted to a fixed amplitude
differential signal using a multistage, limiting LO amplifier.
This results in consistent performance over a range of LO input
power. Optimum performance is achieved from −6 dBm to
+10 dBm, but the circuit continues to function at considerably
lower levels of LO input power.
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The performance of this amplifier is critical in achieving a
high intercept passive mixer without degrading the noise floor
of the system. This is a critical requirement in an interferer rich
environment, such as cellular infrastructure, where blocking
interferers can limit mixer performance. The bandwidth of the
intermodulation performance is somewhat influenced by the
current in the LO amplifier chain. For dc current sensitive
applications, it is permissible to reduce the current in the
LO amplifier by raising the value of the external bias control
resistor. For dc current critical applications, the LO chain
can operate with a supply voltage as low as 3.3 V, resulting in
substantial dc power savings.
In addition, when operating with supply voltages below 3.6 V,
the ADL5355 has a power-down mode that permits the dc
current to drop to <200 μA.
All of the logic inputs are designed to work with any logic family
that provides a Logic 0 input level of less than 0.4 V and a Logic 1
input level that exceeds 1.4 V. All logic inputs are high impedance
up to Logic 1 levels of 3.3 V. At levels exceeding 3.3 V, protection
circuitry permits operation up to 5.5 V, although a small bias
current is drawn.
All pins, including the RF pins, are ESD protected and have
been tested up to a level of 1500 V HBM and 500 V CDM.
ADL5355