TA0016
TA0016
End RFIC
RF2403: European Applications for RF2403 Cordless Telephone Front
A front end RFIC for cordless telephone applications
has been developed for use in the 902MHz to 928MHz
ISM (Industrial-Scientific-Medical) band in the United
States under Part 15 of the FCC Rules. Potential appli-
cations for this RFIC in this frequency band include
cordless telephones, wireless LANs, wireless security
systems and point-of-sale (POS) terminals.
This RFIC, the RF2403, consists of a single-stage
LNA, a two-stage PA with 21dBm of output power and
a transmit/receive switch. The RFIC is built using a
commercial GaAs MESFET process, and is packaged
in a SOP-16 narrowbody surface-mount package. The
circuit operates with a +5.0V supply, and has separate
enable lines which control the bias to the transmit and
receive functions. All bias and control signals operate
with voltages which lie between ground potential and
V
DD
. With both enable lines at logic low, the circuit is in
a 鈥減ower down鈥?mode in which it draws approximately
1.0mA of leakage current from the V
DD
supply. Some
external passive components are required, primarily for
DC blocking and RF bypassing functions. The PA out-
put impedance matching circuitry, consisting of a pi-
network, is realized using external passive compo-
nents in order to both conserve die area and to reduce
parasitic losses. This same RFIC has been evaluated
for use in 433MHz European applications, and has
been found to have very good RF performance there.
Although no changes have been made to the RFIC
itself, several changes to the application circuit are
necessary for operation at 433MHz. Table 1 shows the
component values for both versions of the RF2403
application circuit. The two application schematics are
shown, for 433MHz operation and for 915MHz opera-
tion, in Figures 1 and 2, respectively. The resulting RF
performance for these circuits is shown in Table 2. The
I/O port return losses are somewhat degraded at
433MHz, primarily due to the excess reactance of the
on-chip DC blocking capacitors in the RFIC. The
RF2403 does have comparable gain, output power and
linearity at 433MHz with respect to its performance at
915MHz.
RF Specification
LNA Gain
1
LNA NF
1
LNA P
1dB1
RX IRL, ANT port
1
LNA ORL
PA Small Signal Gain
1
PA P
1dB1
PA IRL
PA ORL, ANT port
1
Measured Performance (All Typical) @V
DD
=5.0V
433MHz Circuit
17dB
2.4dB
+6.0dBm
6.0dB
15dB
28dB
19.0dBm
11dB
11.5dB
17.5dBm
915MHz Circuit
16dB
2.7dB
+6.0dBm
9.0dB
13dB
28dB
21.0dBm
17dB
10.5dB
16.7dBm
13
TECHNICAL NOTES
AND ARTICLES
PA Two-tone P
OUT1,2
@ -25dBc IMD3
Table 2. RF2403 measured performance, using the two application schematics
Note 1: Performance is measured through the monolithic T/R switch
Note 2: f
1
=432.5MHz, f
2
=433.5MHz, or, f
1
=914.5MHz, f
2
=915.5MHz
Copyright 1997-2000 RF Micro Devices, Inc.
13-85
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