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5-35
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Product Description
Ordering Information
Typical Applications
Features
Functional Block Diagram
RF Micro Devices, Inc.
7625 Thorndike Road
Greensboro, NC 27409, USA
Tel (336) 664 1233
Fax (336) 664 0454
http://www.rfmd.com
Optimum Technology Matching Applied
Si BJT
GaAs MESFET
GaAs HBT
Si Bi-CMOS
!
SiGe HBT
Si CMOS
1
2
3
4
5
6
7
8
1 6
1 5
1 4
1 3
1 2
1 1
1 0
9
GC
PHASE
VDD1
GND2
LO IN
GND1
I REF
I SIG
STAND BY
VDD2
VDD3
GND3
RF OUT
GND4
Q REF
Q SIG
POWER
CONTROL
-45
+45
RF2423
100mW SPREAD-SPECTRUM TRANSMITTER IC
Digital and Analog Communication Systems
Spread-Spectrum Communication Systems
Portable Battery-Powered Equipment
GMSK, QPSK, DQPSK, QAM Modulation
AM, SSB, DSB Modulation
The RF2423 is a monolithic integrated transmitter IC
capable of universal direct modulation for UHF AM, PM,
or compound carriers. The transmitter may be used
stand-alone for applications requiring not more than
100mW output power, or may be used to drive a final
power amplifier. The maximum output level is 100mW,
and is adjustable over a 25dB range by a single positive
voltage. This low-cost IC implements differential amplifi-
ers for the modulation inputs, 90 degree carrier phase
shift network, carrier limiting amplifiers, two matched dou-
bly-balanced mixers, variable gain summing amplifier for
level control, and 100mW linear (class AB) output ampli-
fier.
Single 5V Power Supply
100mW Output Power Into 50
25dB Gain Control Range
Excellent Phase & Amplitude Balance
Digitally Controlled Stand-By Mode
800MHz to 1000MHz Operation
RF2423
100mW Spread-Spectrum Transmitter IC
RF2423 PCBA
Fully Assembled Evaluation Board
5
Rev A3 001218
.010
.004
.065
.043
.244
.228
.050
.016
.010
.007
.157
.150
.393
.386
.018
.014
1
.050
8 MAX
0MIN
Package Style: SOP-16
5-36
RF2423
Rev A3 001218
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Absolute Maximum Ratings
Parameter
Rating
Unit
Supply Voltage
-0.5 to +7.5
V
DC
Power Down Voltage (V
PD
)
V
DD
+0.4
V
DC
Input LO and RF Levels
+6
dBm
Operating Ambient Temperature
-40 to +85
C
Storage Temperature
-40 to +150
C
Parameter
Specification
Unit
Condition
Min.
Typ.
Max.
Carrier Input (LO IN)
T = 25 C, V
DD
=5.3V, V
GC
= 5.3V
Frequency Range
800 to 1000
MHz
Power Level
0 to +6
dBm
Input Impedance
55- j120
915MHz
Modulation Input
Frequency Range
DC to 100
MHz
Reference Voltage (V
REF
)
2.0 to 3.0
V
Modulation for 100mW Output
Power (I & Q)
V
REF
2
V
Maximum Modulation (I & Q)
V
REF
2.5
V
Quadrature Phase Error
3
Input Impedance
3000
DC Offset (I & Q)
40
200
mV
RF Output
V
DD
= 5.3V, VGC =5.3V, LO power= 0dBm,
LO frequency=915MHz, SSB, I/Q= 2.0V
P
sine wave, V
REF
=3V
Output Power
+22
+22
dBm
-15
-10
+5
dBm
V
GAIN
=0V
Output Impedance
50
Output VSWR
2:1
Second Harmonic Output
-45
dBc
Other Harmonics Output
<-20
dBc
Sideband Suppression
25
35
dB
Carrier Suppression
22
30
dB
Modulation DC offset can be externally
adjusted for optimum suppression. Carrier
suppression is then typically better than
40dB.
Output Level Control
Control Range
25
dB
Control Voltage
1 to 4
V
Control Input Current
<1.5
mA
Standby Mode
Turn On/Off Time
<100
ns
STANDBY Input Impedance
>50
k
Power Down "ON"
V
CC
V
Threshold voltage; Part is turned "ON"
Power Down "OFF"
0
V
Threshold voltage; Part is turned "OFF"
Power Supply
Voltage
5
V
Specifications
4.5 to 6.0
V
Operating limits
Current
60
110
170
mA
Total, 100mW output power
50
mA
Total, minimum output power
2
20
mA
Standby mode
Caution! ESD sensitive device.
RF Micro Devices believes the furnished information is correct and accurate
at the time of this printing. However, RF Micro Devices reserves the right to
make changes to its products without notice. RF Micro Devices does not
assume responsibility for the use of the described product(s).
5-37
RF2423
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Pin
Function
Description
Interface Schematic
1
GC
Gain control of the RF amplifier. This pin can be used to control the out-
put power over a 25dB range. Output power is the lowest when the
control voltage is 1V or lower, and the highest when set to 4V or higher.
When a fixed maximum output level is needed, it is recommended to
connect this pin to VDD.
2
PHASE
This pin adjusts the phase of the I/Q signals. However, the control is
very sensitive and hard to control. Control voltage change for a few
degrees adjustment is in the order of 10mV. Device to device and tem-
perature variation are not characterized. Therefore it is not recom-
mended to use this pin; leave it not connected. Do NOT connect it to
ground. For compensating large errors in the I/Q signals supplied to the
device or in control loops, this pin may prove useful.
3
VDD1
Power supply to all circuits except the RF output stages. It is recom-
mended to put some RF decoupling on this pin, though it is not critical.
An optional 0.1
F capacitor is required if no other low frequency
bypass capacitor is nearby.
4
GND2
Ground connection for the gain controlled RF amplifier. Keep traces
physically short and connect immediately to ground plane for best per-
formance.
5
LO IN
Modulator LO input. A series 22nH inductor can be used for matching.
This pin is NOT internally DC blocked. An external blocking capacitor
must be provided if the pin is connected to a device with DC present. A
DC path to ground (i.e. an inductor or resistor to ground) is, however,
acceptable at this pin. If a blocking capacitor is required, a value of
33pF is recommended.
6
GND1
Ground connection for the baseband, LO and mixer circuits. Keep
traces physically short and connect immediately to ground plane for
best performance.
7
I REF
Reference voltage for the I mixer. This voltage should be the same as
the DC voltage supplied to the I SIG pin. To obtain a carrier suppres-
sion of better than 25dB it may be tuned 0.15V (relative to the I SIG
DC voltage). Without tuning, it will typically be better than 25dB. Input
impedance of this pin is about 3k
.
8
I SIG
Baseband input to the I mixer. This pin is DC coupled. Maximum output
power is obtained when the input signal has a peak to peak amplitude
of 5V. The DC level supplied to this pin should be VDD2/2. Input imped-
ance of this pin is about 3k
.
9
Q SIG
Baseband input to the Q mixer. This pin is DC coupled. Maximum out-
put power is obtained when the input signal has a peak to peak ampli-
tude of 5V. The DC level supplied to this pin should be VDD2/2. Input
impedance of this pin is about 3k
.
10
Q REF
Reference voltage for the Q mixer. This voltage should be the same as
the DC voltage supplied to the Q SIG pin. To obtain a carrier suppres-
sion of better than 25dB it may be tuned 0.15V (relative to the Q SIG
DC voltage). Without tuning it will typically be better than 25dB. Input
impedance of this pin is about 3k
.
10 k
5 k
GC
PHASE
4 k
LO IN
1 k
2 k
2 k
I SIG
I REF
1 k
1 k
2 k
2 k
Q SIG
Q REF
1 k
5-38
RF2423
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Pin
Function
Description
Interface Schematic
11
GND4
Ground connection for the RF driver and output stage. Keep traces
physically short and connect immediately to ground plane for best per-
formance. Having a good ground connection on this pin is extremely
important due to the high RF levels in the circuits connected to this pin.
12
RF OUT
50
RF output. This pin is not internally DC blocked and an external
blocking capacitor of 22pF is needed.
13
GND3
Ground connection for the RF driver and output stage. Keep traces
physically short and connect immediately to ground plane for best per-
formance. Having a good ground connection on this pin is extremely
important due to the high RF levels in the circuits connected to this pin.
14
VDD3
Power supply for the RF output stage. A 33pF external bypass capaci-
tor is required and an optional 0.1
F will be required if no other low fre-
quency bypass capacitors are nearby. The trace length between the pin
and the bypass capacitors should be minimized. The ground side of the
bypass capacitors should connect immediately to ground plane.
Having good bypassing on this pin is especially important because of
the high levels of RF signal on the circuits connected to this pin.
15
VDD2
Power supply for the RF driver stage. A 33pF external bypass capacitor
is required and an optional 0.1
F will be required if no other low fre-
quency bypass capacitors are near by. The trace length between the
pin and the bypass capacitors should be minimized. The ground side of
the bypass capacitors should connect immediately to ground plane.
Having good bypassing on this pin is especially important because of
the high levels of RF signal on the circuits connected to this pin.
16
STANDBY
Standby mode control. When this pin is 0V all circuits are turned off,
and when this pin is VDD all circuits are operating. This is a high
impedance input, internally connected to the gate of a few transistors.
To minimize current consumption in power down mode, this pin should
be as close to 0 V as possible, or even a little negative. Turn-on voltage
of some parts of the circuit may be as low as 0.0 V. In order to maxi-
mize output power this pin should be as close to VDD as possible dur-
ing normal operation.
RF OUT
V
DD
5-39
RF2423
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Application Schematic
C
Note 1
Note 1
100 nF
C
22 nH
CMOS
R
R
C
100 nF
V
DD
R
C
R
22 pF
V
REF
100 nF
V
DD
V
REF
I INPUT
LO INPUT
GAIN
CONTROL
STANDBY
RF OUTPUT
Q INPUT
1
2
3
4
5
6
7
8
1 6
1 5
1 4
1 3
1 2
1 1
1 0
9
POWER
CONTROL
-45
+45
33 pF SMD capacitor mounted as close to the package pin as possible, grounded
through via to the ground plane with minimum inductance.
The values of R and C depend on the lowest frequency of the baseband signal.
NOTE 1:
NOTE 2:
5-40
RF2423
Rev A3 001218
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Evaluation Board Schematic
(Download Bill of Materials from www.rfmd.com.)
C3
36 pF
C6
100 nF
C7
100 pF
R2
33
C1
36 pF
P2-2
P2-5
C5
100 nF
C4
100 nF
P2-1
P1-3
P1-4
L1
22 nH
R1
22
R3
0
P1-2
P1-1
R4
22
C2
36 pF
1
2
3
4
5
6
7
8
1 6
1 5
1 4
1 3
1 2
1 1
1 0
9
POWER
CONTROL
-45
+45
P2-4
LO IN
J1
RF OUT
J2
P2-4
P1-1
P1-3
P1
IREF
QREF
QSIG
1
2
3
4
5
P2-1
P2-2
P2
GND
PHASE
LEVEL
1
2
3
4
5
GND
ISIG
STBY
VDD
P1-2
P1-4
P2-4
P2-5
2423400 Rev -
5-41
RF2423
Rev A3 001218
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Evaluation Board Layout
1.25" x 1.25"
Board Thickness 0.031"; Board Material FR-4
5-42
RF2423
Rev A3 001218
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