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Optimum Technology Matching® Applied
GaAs HBT
InGaP HBT
GaAs MESFET
SiGe BiCMOS
Si BiCMOS
SiGe HBT
GaAs pHEMT
Si CMOS
Si BJT
GaN HEMT
Functional Block Diagram
RF MICRO DEVICES®, RFMD®, Optimum Technology Matching®, Enabling Wireless Connectivity™, PowerStar®, POLARIS™ TOTAL RADIO™ and UltimateBlue™ are trademarks of RFMD, LLC. BLUETOOTH is a trade-
mark owned by Bluetooth SIG, Inc., U.S.A. and licensed for use by RFMD. All other trade names, trademarks and registered trademarks are the property of their respective owners. ©2006, RF Micro Devices, Inc.
Product Description
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
Ordering Information
1
2
3
4
5
6
7
14
13
12
11
10
9
8
LNA IN
GND
VDD1
VDD2
IF BYP
IF2 OUT
IF1 OUT
LNA OUT
GND
GND
RF IN
GND
DEC
LO IN
LNA
MIXER
BUFFER
10pF
RF AMP
RF2418
LOW CURRENT LNA/MIXER
The RF2418 is a monolithic integrated UHF receiver front-end. The IC con-
tains all of the required components to implement the RF functions of the
receiver except for the passive filtering and LO generation. It contains an
LNA (low-noise amplifier), a second RF amplifier, a dual-gate GaAs FET
mixer, and an IF output buffer amplifier which will drive a 50Ω load. In
addition, the IF buffer amplifier may be disabled and a high impedance
output is provided for easy matching to IF filters with high impedances.
The output of the LNA is made available as an output to permit the inser-
tion of a bandpass filter between the LNA and the RF/Mixer section. The
LNA section may be disabled by removing the VDD1 connection to the IC.
Features
Single 3V to 6.5V Power Sup-
ply
High Dynamic Range
Low Current Drain
High LO Isolation
LNA Power Down Mode for
Large Signals
Applications
UHF Digital and Analog
Receivers
Digital Communication Sys-
tems
Spread-Spectrum Communi-
cation Systems
Commercial and Consumer
Systems
433MHz and 915MHz ISM
Band Receivers
General Purpose Frequency
Conversion
RF2418 Low Current LNA/Mixer
RF2418PCBA-41X Fully Assembled Evaluation Board
Rev A7 DS060203
9
RoHS Compliant & Pb-Free Product
Package Style: SOIC-14
2 of 12
RF2418
Rev A7 DS060203
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
Absolute Maximum Ratings
Parameter Rating Unit
Supply Voltage -0.5 to 7 VDC
Input LO and RF Levels +6 dBm
Ambient Operating Temperature -40 to +85 °C
Storage Temperature -40 to +150 °C
Parameter Specification Unit Condition
Min. Typ. Max.
Overall T=25°C, VCC=5V, RF=850MHz,
LO= 921MHz
RF Frequency Range 400 to 1100 MHz
Cascade Power Gain 23 dB High impedance output
Cascade IP3-13 dBm Referenced to the input
Cascade Noise Figure 2.4 dB Single sideband, includes image filter with
1.0dB insertion loss
First Section (LNA)
Noise Figure 1.8 2.0 dB
Input VSWR 1.5:1 With external series matching inductor
Input IP3 +3.0 +4.0 dBm
Gain 13 14 dB
Reverse Isolation 40 dB
Output VSWR 1.5:1
Second Section (RF Amp,
Mixer, IF1)
High impedance output
Noise Figure 9.5 dB Single Sideband
Input VSWR 1.5:1 With external series matching inductor
Input IP3 +1 dBm
Conversion Power Gain 7 9 dB
Output Impedance 4000||10pF ΩOpen Collector
Second Section (RF Amp,
Mixer, IF2)
Buffered output, 50Ω load
Noise Figure 10 dB Single Sideband
Input VSWR 1.5:1 With external series matching inductor
Input IP3 -0.5 0 dBm
Conversion Gain 5 6 dB
Output Impedance 30 Ω
Caution! ESD sensitive device.
Exceeding any one or a combination of the Absolute Maximum Rating conditions may
cause permanent damage to the device. Extended application of Absolute Maximum
Rating conditions to the device may reduce device reliability. Specified typical perfor-
mance or functional operation of the device under Absolute Maximum Rating condi-
tions is not implied.
RoHS status based on EUDirective2002/95/EC (at time of this document revision).
The information in this publication is believed to be accurate and reliable. However, no
responsibility is assumed by RF Micro Devices, Inc. ("RFMD") for its use, nor for any
infringement of patents, or other rights of third parties, resulting from its use. No
license is granted by implication or otherwise under any patent or patent rights of
RFMD. RFMD reserves the right to change component circuitry, recommended appli-
cation circuitry and specifications at any time without prior notice.
3 of 12
RF2418
Rev A7 DS060203
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
Parameter Specification Unit Condition
Min. Typ. Max.
LO Input
LO Frequency 300 to 1200 MHz
LO Level -6 to +6 dBm
LO to RF Rejection 15 dB
LO to IF Rejection 40 dB With pin 5 connected to ground.
LO Input VSWR 1.3:1 In order to achieve a low VSWR match at this
input, an 82Ω resistor to ground is placed in
parallel with this port.
Power Supply
Voltage 3.0 6.5 V
Current Consumption 14 mA VCC=5.0V, LNA On, Mixer On, Buffer Off
12 20 26 mA VCC=5.0V, LNA On, Mixer On, Buffer On
6920mAV
CC=5.0V, LNA Off, Mixer On, Buffer Off
4 of 12
RF2418
Rev A7 DS060203
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
Pin Function Description Interface Schematic
1LNA IN
A series 10nH matching inductor is necessary to achieve specified gain
and noise figure at 900MHz. 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 22pF is recommended.
2GND
Ground connection. Keep traces physically short and connect immediately
to ground plane for best performance.
3 VDD1 Supply Voltage for the LNA only. A 22pF external bypass capacitor is
required and an additional 0.01μF is required if no other low frequency
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.
For large input signals, VDD1 may be disconnected, resulting in the LNA’s
gain changing from +11dB to -26dB and current drain decreasing by 4mA.
If the LNA is never required for use, then this pin can be left unconnected
or grounded, and Pin 11 is used as the first input.
4 VDD2 Power supply for the IF buffer amplifier. If the high impedance mixer output
is being used, then this pin is not connected.
5IF BYP
If this pin is connected to ground, an internal 10pF capacitor is connected
in parallel with the mixer output. This capacitor functions as an LO trap,
which reduces the amount of LO to IF bleed-through and prevents high LO
voltages at the mixer output from degrading the mixer’s dynamic range. At
higher IF frequencies, this capacitance, along with parasitic layout capaci-
tance, should be parallel resonated out by the choice of the bias inductor
value at pin 7. If the internal capacitor is not connected to ground, the
buffer amplifier could become unstable. A ~10pF capacitor should be
added at the output to maintain the buffer’s stability, but the gain will not
be significantly affected.
6IF2 OUT
50Ω buffered (open source) output port, one of two output options. Pin 7
must have a bias resistor to VDD and pin 6 must have a bias resistor to
ground (see Buffered Output Application Schematic) in order to turn the
buffer amplifier on. Current drain will increase by approximately 8mA at
5V, and by approximately 5mA at 3V. It is recommended that these bias
resistors be less than 1kΩ.
7IF1 OUT
High impedance (open drain) output port, one of two output options. This
pin must be connected to VDD through a resistor or inductor in order to
bias the mixer, even when using IF2 Output. In addition, a 0.01μF bypass
capacitor is required at the other end of the bias resistor or inductor. The
ground side of the bypass capacitor should connect immediately to ground
plane. This output is intended to drive high impedance IF filters. The rec-
ommended matching network is shunt L, series C (see the application
schematic, high impedance output). This topology will provide matching,
bias, and DC-blocking.
8LO IN
Mixer LO input. A high-pass matching network, such as a single shunt
inductor (as shown in the application schematics), is the recommended
topology because it also rejects IF noise at the mixer input. This filtering is
required to achieve the specified noise figures. 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 induc-
tor or resistor to ground) is, however, acceptable at this pin. If a blocking
capacitor is required, a value of 22pF is recommended.
9RF BYP
Connection for the external bypass capacitor for the mixer RF input
preamp. 1000pF is recommended. The trace length between the pin and
the capacitor should be minimized. The ground side of the bypass capaci-
tor should connect immediately to ground plane.
LNA IN
IF2 OUT
IF1 OUT
LO IN
5 of 12
RF2418
Rev A7 DS060203
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
Package Drawing
Pin Function Description Interface Schematic
10 GND Same as pin 2.
11 RF IN Mixer RF Input port. For a 50Ω match at 900MHz use a 15nH series
inductor. This pin is NOT internally DC-blocked. An external blocking capac-
itor 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 22pF is
recommended.To minimize the mixer’s noise figure, it is recommended to
have a RF bandpass filter before this input. This will prevent the noise at
the image frequency from being converted to the IF.
12 GND Same as pin 2.
13 GND Same as pin 2.
14 LNA OUT 50Ω output. Internally DC-blocked.
RF IN
LNA OUT
0.156
0.148
0.059
0.057
0.252
0.236
0.010
0.004
.018
.014
8° MAX
0° MIN
0.0500
0.0164
0.010
0.007
0.347
0.339
0.050
6 of 12
RF2418
Rev A7 DS060203
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
Application Schematic
High Impedance Output Configuration
850MHz
1
2
3
4
5
6
7
14
13
12
11
10
9
8
LNA
MIXER
BUFFER
10pF
RF AMP
I
F
F
i
l
t
e
r
,
H
i
Z
IF O U T
RF IN
I
m
a
g
e
F
i
l
t
e
r
5
0
Ω
10 nH
LO IN
VDD
VDD
L1 and C1 are picked to m atch the mixer's output im pedance (4 kΩ II 10 pF) to the IF
filter's im pedance, at the IF frequency. C1 also serves as a D C block, in case the IF filter is
not an open circuit at DC.
L1
100 nF
C1
47 pF100 nF
10 nH
4 pF
1 nF
15 nH
7 of 12
RF2418
Rev A7 DS060203
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
Application Schematic
Buffered Output Configuration
850MHz
1
2
3
4
5
6
7
14
13
12
11
10
9
8
LNA
MIXER
BUFFER
10pF
RF AMP
I
F
F
i
l
t
e
r
,
5
0
Ω
IF O U T
R F IN
I
m
a
g
e
F
i
l
t
e
r
,
5
0
Ω
15nH
10 nH
LO IN
VDD
VDD
L1 should parallel resonate, at the IF frequency, with the internal
10pF capacitor plus any extra parasitic layout capacitance.
R1 and R2 are bias resistors that set the bias current for the buffer
amplifier. The value recommended is 510 W , each. Higher values
will decrease the current consumption but also decrease the output
level at which voltage clipping begins to occur. At lower IF
frequencies, where the internal 10 pF capacitor does not roll off the
conversion gain, L1 may be elim inated.
C1 is a blocking capacitor, in case the IF filter's input is not an open
circuit at DC.
10 nH
47 pF100 nF
R1
C1
L1R2
100 nF 100 nF
1 nF
4 pF
8 of 12
RF2418
Rev A7 DS060203
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
Evaluation Board Schematic
RF=850MHz, IF=71MHz
1
2
3
4
5
6
7
14
13
12
11
10
9
8
LNA
MIXER
BUFFER
10pF
RF AMP
L3
10 nH
C3
47 pF
C1
0.1 μF
L1
1 μH
L2
18 nH
C2
1 nF
R3
610 Ω
R1
300 Ω
E2 E1
L4
10 nH
R4
5.11 kΩ
C4
0.1 μF
C5
3 pF to 5 pF
see note
Notes:
For high impedance output
1) Populate L1 and TP1
2) Remove jumper E1 to E2
50 Ω μstrip
50 Ω μstrip
50 Ω μstrip
2418400C
Jumper
TP1
see note
VDD
50 Ω μstrip
P1
1
2
3
NC
GND
P1-3 VDD
J1
LNA IN
50 Ω μstrip
J2
IF OUT
P1-3
J3
LO IN
J4
RF IN
J5
LNA OUT
9 of 12
RF2418
Rev A7 DS060203
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
Evaluation Board Layout
Board Size 1.52” x 1.52”
Board Thickness 0.031”, Board Material FR-4
10 of 12
RF2418
Rev A7 DS060203
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
High Impedance Mixer Gain versus Voltage, RF=850MHz
7.0
7.5
8.0
8.5
9.0
9.5
10.0
3.03.54.04.55.05.56.06.5
Voltage (V)
Gain (dB)
T =-40
T = 26
T = 85
High Impedance Casc. Gain versus Voltage,
RF=850MHz
14.0
16.0
18.0
20.0
22.0
24.0
26.0
3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5
Voltage (V)
Gain (dB)
T =-40
T =26
T = 85
High Impedance Mixer Input IP3 versus Voltage,
RF=850MHz
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5
Voltage (V)
IIP3 (dBm)
T =-40
T = 26
T = 85
High Impedance Casc. Input IP3 versus Voltage,
RF=850MHz
-15.0
-14.5
-14.0
-13.5
-13.0
-12.5
-12.0
-11.5
-11.0
-10.5
-10.0
3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5
Voltage (V)
IIP3 (dBm)
T =-40
T =26
T = 85
Buffered LNA Gain versus Voltage,
RF=850MHz
7.0
8.0
9.0
10.0
11.0
12.0
13.0
14.0
15.0
16.0
17.0
3.03.54.04.55.05.56.06.5
Voltage (V)
Gain (dB)
T =-40
T = 26
T =85
Buffered Mixer Gain versus Voltage,
RF=850MHz
5.0
6.0
7.0
8.0
9.0
10.0
11.0
12.0
13.0
14.0
15.0
3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5
Voltage (V)
Gain (dB)
T =-40
T = 26
T = 85
11 of 12
RF2418
Rev A7 DS060203
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
Buffered Casc. Gain versus Voltage,
RF=850MHz
5.0
10.0
15.0
20.0
25.0
30.0
3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5
Voltage (V)
Gain (dB)
T =-40
T =26
T = 85
Buffered LNA Input versus Voltage,
RF=850MHz
-10.0
-8.0
-6.0
-4.0
-2.0
0.0
2.0
4.0
6.0
3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5
Voltage (V)
IIP3 (dBm)
T =-40
T = 26
T =85
Buffered Mixer Input IP3 versus Voltage,
RF=850MHz
-3.0
-2.5
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5
Voltage (V)
IIP3 (dBm)
T =-40
T = 26
T = 85
Buffered Casc. Input IP3 versus Voltage,
RF=850MHz
-16.0
-15.0
-14.0
-13.0
-12.0
-11.0
-10.0
3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5
Voltage (V)
IIP3 (dBm)
T =-40
T =26
T = 85
Buffered LNA Noise Figure versus Voltage,
RF=850MHz Part to Part Variation
1.4
1.6
1.8
2.0
3.03.54.04.55.05.56.06.5
Voltage (V)
Gain (dB)
Part 1
Part 2
Part 3
Part 4
Part 5
Buffered Mixer Noise Figure versus Voltage,
RF=850MHz Part to Part Variation
9.0
9.5
10.0
10.5
11.0
3.03.54.04.55.05.56.06.5
Voltage (V)
Gain (dB)
Part 1
Part 2
Part 3
Part 4
Part 5
12 of 12
RF2418
Rev A7 DS060203
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.
