ADF7020-1BCPZ-RL Analog Devices Inc, ADF7020-1BCPZ-RL Datasheet - Page 25

• Manufacturer Part Number: ADF7020-1BCPZ-RL
• Description: IC,RF Modulator/Demodulator,LLCC,48PIN,PLASTIC
• Manufacturer: Analog Devices Inc

Specifications of ADF7020-1BCPZ-RL

• Design Resources: Low power, Long Range, ISM Wireless Measuring Node (CN0164)
• Frequency: 431MHz ~ 478MHz and 862MHz ~ 956MHz
• Data Rate - Maximum: 200kbps
• Modulation Or Protocol: ASK, FSK
• Applications: Data Transfer, RKE, Remote Control/Security Systems
• Power - Output: -16dBm ~ 13dBm
• Sensitivity: -119dBm
• Voltage - Supply: 2.3 V ~ 3.6 V
• Current - Receiving: 17.6mA
• Current - Transmitting: 21mA
• Data Interface: PCB, Surface Mount
• Antenna Connector: PCB, Surface Mount
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 48-LFCSP
• Operating Temperature (min): -40C
• Operating Temperature (max): 85C
• Operating Temperature Classification: Industrial
• Product Depth (mm): 7mm
• Product Length (mm): 7mm
• Operating Supply Voltage (min): 2.3V
• Operating Supply Voltage (typ): 2.5/3.3V
• Operating Supply Voltage (max): 3.6V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: EVAL-ADF7020-1DBZ8 - BOARD EVAL ADF7020-1 128-142MHZEVAL-ADF7020-1DBZ7 - BOARD EVAL ADF7020-1 310-340MHZEVAL-ADF7020-1DBZ6 - BOARD EVAL ADF7020-1 470-510MHZEVAL-ADF7020-1DBZ4 - BOARD EVAL ADF7020-1 405-435MHZEVAL-ADF7020-1DBZ5 - BOARD EVAL ADF7020-2 ADJ FREQ
• Memory Size: -
• Lead Free Status / Rohs Status: Compliant

APPLICATIONS
LNA/PA MATCHING
The ADF7020-1 exhibits optimum performance in terms of
sensitivity, transmit power, and current consumption only if its
RF input and output ports are properly matched to the antenna
impedance. For cost-sensitive applications, the ADF7020-1 is
equipped with an internal Rx/Tx switch, which facilitates the
use of a simple combined passive PA/LNA matching network.
Alternatively, an external Rx/Tx switch, such as the Analog
Devices ADG919, can be used, which yields a slightly improved
receiver sensitivity and lower transmitter power consumption.
External Rx/Tx Switch
Figure 33 shows a configuration using an external Rx/Tx switch.
This configuration allows an independent optimization of the
matching and filter network in the transmit and receive path
and is therefore more flexible and less difficult to design than
the configuration using the internal Rx/Tx switch. The PA is
biased through Inductor L1, and C1 blocks the dc current. Both
elements, L1 and C1, also form the matching network, which
transforms the source impedance into the optimum PA load
impedance, Z
Z
output power, the frequency range, the supply voltage range,
and the temperature range. Selecting an appropriate Z
helps to minimize the Tx current consumption in the
application. The Specifications section lists a number of
Z
conditions, however, it is recommended to obtain a suitable
Z
Due to the differential LNA input, the LNA matching network
must be designed to provide both a single-ended to differential
conversion and a complex conjugate impedance match. The
network with the lowest component count that can satisfy these
requirements is the configuration shown in Figure 33, which
consists of two capacitors and one inductor. A first-order
implementation of the matching network can be obtained by
understanding the arrangement as two L type matching networks
ANTENNA
Rx/Tx – SELECT
OPT
OPT
OPT
_PA depends on various factors, such as the required
_PA values for representative conditions. Under certain
_PA value by means of a load-pull measurement.
ADG919
Figure 33. ADF7020-1 with External Rx/Tx Switch
OPT
_PA.
OPTIONAL
OPTIONAL
(SAW)
BPF
LPF
C
C
B
A
V
BAT
Z
Z
Z
L
L1
IN
IN
OPT
A
_RFIN
_RFIN
_PA
ADF7020-1
PA_OUT
RFIN
RFINB
LNA
OPT
_PA
PA
Rev. 0 | Page 25 of 48
in a back-to-back configuration. Due to the asymmetry of the
network with respect to ground, a compromise between the input
reflection coefficient and the maximum differential signal swing
at the LNA input must be established. The use of appropriate
CAD software is strongly recommended for this optimization.
Depending on the antenna configuration, the user might
need a harmonic filter at the PA output to satisfy the spurious
emission requirement of the applicable government regulations.
The harmonic filter can be implemented in various ways, such
as a discrete LC pi or T-stage filter. The immunity of the
ADF7020-1 to strong out-of-band interference can be improved
by adding a band-pass filter in the Rx path, or alternatively by
selecting one of the high linearity modes outlined in Table 6.
Internal Rx/Tx Switch
Figure 34 shows the ADF7020-1 in a configuration where the
internal Rx/Tx switch is used with a combined LNA/PA
matching network. This is the configuration used in the
ADF7020-1DBX Evaluation boards. For most applications, the
slight performance degradation of 1 dB to 2 dB caused by the
internal Rx/Tx switch is acceptable, allowing the user to take
advantage of the cost saving potential of this solution. The
design of the combined matching network must compensate for
the reactance presented by the networks in the Tx and the Rx
paths, taking the state of the Rx/Tx switch into consideration.
The procedure typically requires several iterations until an
acceptable compromise is reached. The successful implementation
of a combined LNA/PA matching network for the ADF7020-1 is
critically dependent on the availability of an accurate electrical
model for the PC board. In this context, the use of a suitable CAD
package is strongly recommended. To avoid this effort, however, a
small form-factor reference design for the ADF7020-1 is provided,
including matching and harmonic filter components. The design
is on a 2-layer PCB to minimize cost. Gerber files are available
on the
ANTENNA
www.analog.com
BPF OR LPF
OPTIONAL
Figure 34. ADF7020-1 with Internal Rx/Tx Switch
website.
C1
C
C
A
B
V
BAT
L
L1
Z
Z
Z
A
IN
IN
OPT
_RFIN
_RFIN
_PA
ADF7020-1
PA_OUT
RFIN
RFINB
ADF7020-1
LNA
PA