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Copyright 1997-2000 RF Micro Devices, Inc.
A front end RFIC for cordless telephone applications
has been developed for use in the 902MHz to 928 MHz
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 "power down" 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 915 MHz 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
Measured Performance (All Typical) @V
DD
=5.0V
433MHz Circuit
915MHz Circuit
LNA Gain
1
17dB
16dB
LNA NF
1
2.4dB
2.7dB
LNA P
1dB
1
+6.0dBm
+6.0dBm
RX IRL, ANT port
1
6.0dB
9.0dB
LNA ORL
15dB
13dB
PA Small Signal Gain
1
28dB
28dB
PA P
1dB
1
19.0dBm
21.0dBm
PA IRL
11dB
17dB
PA ORL, ANT port
1
11.5dB
10.5dB
PA Two-tone P
OUT
1,2
@ -25dBc IMD3
17.5dBm
16.7dBm
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
=432.5 MHz, f
2
= 433.5MHz, or, f
1
=914.5MHz, f
2
= 915.5MHz
TA0016
TA0016
RF2403: European Applications for RF2403 Cordless Telephone Front
End RFIC
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Copyright 1997-2000 RF Micro Devices, Inc.
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
L2
Jumper
C4
100 pF
L1
47 nH
P1-1
C5
100 pF
ANT
J1
C6
100 pF
LNA OUT
J2
P2-3
P1-1
C7
220 pF
C1
220 pF
C2
0.1
F
L4
10 nH
L3
33 nH
C9
22 pF
P2-1
C8
100 pF
50
strip
PA IN
J3
C10
0.1
F
C11
1.5 pF
C3
N/A
50
strip
50
strip
P1-1
NC
P1
GND
VDD
1
2
3
P2-1
P2-3
P2
RXPC
GND
TXPC
1
2
3
R1
150
Figure 1. RF2403 Application Circuit for 433 MHz European Applications
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
L2
3.3 nH
C4
47 pF
L1
22 nH
P1-1
C5
47 pF
ANT
J1
C6
47 pF
LNA OUT
J2
P2-3
P1-1
C7
100 pF
C1
100 pF
C2
0.1
F
L4
3.3 nH
L3
33 nH
C9
12 pF
P2-1
C8
47 pF
50
strip
PA IN
J3
C10
0.1
F
C11
0.6 pF
C3
3 pF
50
strip
50
strip
P1-1
NC
P1
GND
VDD
1
2
3
P2-1
P2-3
P2
RXPC
GND
TXPC
1
2
3
Figure 2. RF2403 Application Circuit for 915 MHz ISM Applications
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Copyright 1997-2000 RF Micro Devices, Inc.
Component Designation
Value (0805 size, unless noted otherwise)
433MHz Circuit
915MHz Circuit
C1
220pF
100pF
C2
0.1
F
0.1
F
C3
Omit
3.0pF
C4
100pF
47pF
C5
100pF
47pF
C6
100pF
47pF
C7
220pF
100pF
C8
100pF
47pF
C9
22pF
12pF
C10
0.1
F
0.1
F
C11
1.5pF ATC 100A
0.6pF ATC 100A
L1
47nH
22nH
L2
Replace with metal strip jumper
3.3nH
L3
33nH
33nH
L4
10nH
3.3nH
R1
150
1206, added shunt to ground on DC-
isolated side of C8
Omit
Table 1. Application circuit component values
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