12-9
12
P
LLs
and
V
C
O
s
Preliminary
Product Description
Ordering Information
Typical Applications
Features
Functional Block Diagram
RF Micro Devices, Inc.
7628 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
8
PD
7
VCC2
6
GND2
5
RF OUT
4
VTUNE
3
FDBK
2
GND1
1
VCC1
RF2506
VHF/UHF VCO/HIGH-ISOLATION
BUFFER AMPLIFIER
Low Voltage
Wireless LANs
IF LO for 2.45GHz ISM Band Systems
Wireless Local Loop
Digital Cordless Phones
The RF2506 is an integrated oscillator and buffer ampli-
fier chain designed to achieve low sensitivity to fluctua-
tions in load impedance and power supply noise, while
maintaining superior phase noise performance. The IC
offers great flexibility, yet is easy to use. This product was
designed for use in applications with low supply voltages.
It has a power-down feature and is designed to operate
from 10MHz to 1000MHz with the help of an external res-
onator. Frequency control is achieved with an external
varactor diode. The IC's ease of use, reduced load pull-
ing, small size, and low cost make it an ideal LO (Local
Oscillator) for wireless applications in the VHF/UHF
range. The RF2506 was designed to operate with the
2.4GHz chipset; specifically with the IF portion of the
RF2518 PLL/synthesizer.
High-Isolation/Reduced Load Pulling
Low Current Consumption
-7dBm Output Power
Digitally Controlled Power Down Mode
10MHz to 1GHz Operating Range
Single 2.7V to 3.6V Supply
RF2506
VHF/UHF VCO/High-Isolation Buffer Amplifier
RF2506 PCBA
Fully Assembled Evaluation Board
12
Rev A1 000908
0.006
+ 0.003
0.034
6 MAX
0 MIN
0.021
+ 0.004
0.006
+ 0.002
NOTES:
1. Shaded lead is pin 1.
2. All dimensions are exclusive of flash,
protrusions or burrs.
3. Lead coplanarity: 0.002 with respect
to datum "A".
A
0.192
+ 0.008
0.0256
0.012
0.118
+ 0.004 sq.
Package Style: MSOP-8
Preliminary
12-10
RF2506
Rev A1 000908
12
PLLs
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Absolute Maximum Ratings
Parameter
Rating
Unit
Supply Voltage
-0.5 to +5.8
V
DC
Power Down Voltage (V
PD
)
-0.5 to +5.8
V
DC
Operating Ambient Temperature
-40 to +85
C
Storage Temperature
-55 to +150
C
Parameter
Specification
Unit
Condition
Min.
Typ.
Max.
Overall
Operating Frequency
10 to 1000
MHz
560MHz Operation
T = 25 C, V
CC
= 2.7V, Z
LOAD
=50
,
V
PD
= 2.7V, O/P terminated into LC.
Characterized @ 560MHz as per eval board.
Data will change depending on frequency of
operation and resonant tank network.
Output Power
-3
dBm
2nd Harmonic
-27
dBc
3rd Harmonic
-35
dBc
Load Pulling
50
kHz
P-P
Into 1.75 VSWR Load
V
CC
Pushing
190
kHz/V
Supply sweep from 2.7V to 3.2V
Phase Noise
-110
dBc
100kHz Offset. Better phase noise is achiev-
able by increasing the loaded Q of the reso-
nator circuit.
-90
dBc
10kHz Offset
560MHz Operation
T = 25 C, V
CC
= 2.7V, Z
LOAD
=50
,
V
PD
= 2.7V, O/P terminated in 50
.
Characterized @ 560MHz as per eval board.
Data will change depending on frequency of
operation and resonant tank network.
Output Power
-7
dBm
2nd Harmonic
-11.5
dBc
3rd Harmonic
-15.5
dBc
Load Pulling
35
kHz
P-P
Into 1.75 VSWR Load
V
CC
Pushing
160
kHz/V
Supply sweep from 2.7V to 3.2V
Phase Noise
-107
dBc
100kHz Offset. Better phase noise is achiev-
able by increasing the loaded Q of the reso-
nator circuit.
-88
dBc
10kHz Offset
Power Supply
Operating Voltage
2.7 to 3.6
V
DC
At 2.2V and -40C, output power will be
reduced to typically -11dBm.
Supply Current
9
mA
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).
Preliminary
12-11
RF2506
Rev A1 000908
12
PLLs
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Pin
Function
Description
Interface Schematic
1
VCC1
Power supply connection for the VCO. This pin should be well
bypassed close to the package with a capacitor suitable for the fre-
quency of operation as well as a capacitor to minimize low frequency
noise from the voltage supply. The ground side of the capacitors should
connect immediately to ground plane.
2
GND1
Ground connection for the VCO. Keep traces physically short and con-
nect immediately to ground plane for best performance. In order to min-
imize load pulling, it is recommended that pin 2 has a different return
path to ground than pin 6 (i.e., separate vias to a common ground
plane).
See pin 2.
3
FDBK
Feedback output to resonant circuit. A Colpitts oscillator is formed by
placing a capacitor from this pin to pin 4 and from this pin to ground. A
DC blocking capacitor, suitable for the frequency of operation, should
be used if the external circuitry has DC present or presents a DC path
to ground. See the application schematic of this data sheet for design
details.
See pin 4.
4
VTUNE
Tank circuit input. A resonant circuit is placed from this pin to ground.
The capacitive side is tapped to the FDBK point and the inductive side
includes a varactor for voltage tuning to provide the VCO function. A
DC blocking capacitor, suitable for the frequency of operation, should
be used if the external circuitry has DC present or presents a DC path
to ground. See the application schematic of this data sheet for design
details.
5
RF OUT
RF output pin. This is an open-collector output and must be biased
externally. A shunt bias/matching inductor to V
CC
and a series blocking/
matching capacitor are recommended. See Application Example Sche-
matic.
6
GND2
Ground connection for the buffer amplifiers. Keep traces physically
short and connect immediately to ground plane for best performance.
In order to minimize load pulling, it is recommended that pin 2 has a dif-
ferent return path to ground than pin 6 (i.e., separate vias to a common
ground plane).
7
VCC2
Power supply connection for the buffer amplifiers. This pin should be
well bypassed close to the package with a capacitor suitable for the fre-
quency of operation. The ground side of the capacitor should connect
immediately to ground plane.
8
PD
Power Down pin for the VCO and buffer amplifiers. A logic "low" (0.0 to
0.7V) turns the entire device off and supply current drops to less than
1
A. A logic "high" (
3.0V) turns the device on. Note that the voltage
on this pin should never exceed 5.5V
DC
.
VTUNE
To Bias Ckts.
To Buffer Amps
and Bias Ckts.
FDBK
GND1
Preliminary
12-12
RF2506
Rev A1 000908
12
PLLs
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Application Schematic
Evaluation Board Schematic
(Download Bill of Materials from www.rfmd.com.)
8
7
6
5
4
3
2
1
C13
100 pF
C4
100 pF
PD
C1
10 pF
C2
10 pF
C8
4 pF
C6
100 pF
L1
27 nH
R1
47 k
VTUNE
D1
SMV
1249-011
C7
10 pF
L2
8.2 nH
C5
100 pF
RF OUT
V
CC
V
CC
V
CC
C11
10 uF
+
C3
100 pF
8
7
6
5
4
3
2
1
C4
100 pF
PD
VCC
C7
10 pF
L2
8.2 nH
C5
100 pF
50
strip
J1
RF OUT
VCC
C3
100 pF
C11
10 uF
+
C13
100 pF
C1
10 pF
C2
10 pF
C8
4 pF
C9*
10 pF
L1
27 nH
D1
SMV1249
-011
R1
47 k
C6
100 pF
VTUNE
VCC
P1
1
2
3
CON3
P1-3
PD
GND
VCC
P1-1
C10
10 uF
+
C12
10 nF
P2
1
2
CON3
GND
P2-1
VTUNE
*Not Populated
2506400-
Preliminary
12-13
RF2506
Rev A1 000908
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PLLs
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Evaluation Board Layout 900MHz
Board Size 1.404" x 0.986"
Board Thickness 0.031", Board Material FR-4
Preliminary
12-14
RF2506
Rev A1 000908
12
PLLs
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