ADL5592-EVALZ AD [Analog Devices], ADL5592-EVALZ Datasheet - Page 12

• Manufacturer Part Number: ADL5592-EVALZ
• Description: 250 MHz to 2400 MHz RF Variable Gain Amplifier
• Manufacturer: AD [Analog Devices]

ADL5592
APPLICATIONS INFORMATION
BASIC CONNECTIONS
Figure 17 shows the basic connections for the ADL5592. A
single power supply between 4.75 V and 5.25 V is applied to
the VCC pins. All the VCC pins must be connected to the same
potential. Each power supply pin should be decoupled using a
100 pF capacitor in addition to either a 0.1 μF or 10 μF capacitor.
These capacitors should be located as close as possible to the
device. One of the supply pins (Pin 21) also requires biasing of
an open-collector using an RF choke (Coilcraft 0603CS). The
value of the inductor is dictated by the frequency band of
operation: 270 nH for the 450 MHz, 850 MHz, and 900 MHz
bands and 33 nH for the 1800 MHz and 1900 MHz bands. The
RFIN, RFOUT, and LOOP OUT pins have 50 Ω impedances
and must be ac-coupled.
MIXER ENABLE
SPI CLOCK
LOOP OUT
SPI LATCH
LO INPUT
SPI DATA
VPOS
VPOS
0.1µF
1000pF
0.1µF
0.1µF
0.1µF
100pF
100pF
LOIP
LOIN
VCC
LOOP OUT
LOOP EN
DATA
CLK
LE
DVCC
GND
1000pF
RF OUTPUT
RF INPUT
Figure 17. Basic Connections
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1000pF
ADL5592
PROGRAMMING THE SPI PORT
Both attenuators are programmed with a single 10-bit word.
Figure 18 shows the input and output attenuators, ATTN 1 and
ATTN 2, respectively. Table 4 lists the 10-bit words corresponding
to the various gain levels. The five least significant bits (LSBs)
set the input attenuator, ATTN 1. The five most significant bits
(MSBs) set the output attenuator, ATTN 2.
Figure 19 shows the timing diagram of the SPI port transmission.
DATA is clocked on the rising edge of CLK. The data is latched
and the attenuation is updated on the falling edge of LE (the latch
enable pin). The timing requirements indicated in Figure 19 are
described in Table 5.
RFIN
GND
GND
GND
GND
GND
VCC
Figure 18. Block Diagram of Attenuator Chain
NC
NC
NC
NC
ATTN 1
CHOKE INDUCTOR (COILCRAFT 0603CS)
33nH FOR 1800MHz, 1900MHz BANDS
270nH FOR 450MHz, 850MHz, 900MHz BANDS
AMP
100pF
ATTN 2
10µF
VPOS
RFOUT