RFMD RF3166_1

RF3166
RF3166QuadBand
GSM850/GSM
900/DCS/PCS
Power Amp
Module
QUAD-BAND GSM850/GSM900/DCS/PCS
POWER AMP MODULE
RoHS Compliant & Pb-Free Product
Package Style: Module, 6 mm x 6 mm
Features
„
Ultra-Small 6mmx6mm Package
Size
„
Integrated VREG
„
Complete Power Control Solution
„
Automatic VBATT Tracking Circuit
„
„
DCS/PCS
1
RFIN
9
DCS/PCS
RFOUT
8
GSM
RFOUT
BAND SELECT 2
TX ENABLE 3
VBATT 4
GND 5
No External Components or Routing
VRAMP 6
GSM
7
RF IN
Improved Power Flatness
Applications
„
„
„
„
3V Quad-Band GSM Handsets
Commercial and Consumer Systems
Portable Battery-Powered Equipment
GSM850/EGSM900/DCS/PCS
Products
„
GPRS Class 12
„
Power StarTM Module
Functional Block Diagram
Product Description
The RF3166 is a high-power, high-efficiency power amplifier module with integrated
power control that provides over 50dB of control range. The device is a self-contained 6mmx6mm module with 50Ω input and output terminals. The device is
designed for use as the final RF amplifier in GSM850, EGSM900, DCS and PCS
handheld digital cellular equipment and other applications in the 824MHz to
849MHz, 880MHz to 915MHz, 1710MHz to 1785MHz and 1850MHz to 1910MHz
bands. The RF3166 incorporates RFMD’s latest VBATT tracking circuit, which monitors battery voltage and prevents the power control loop from reaching saturation.
The VBATT tracking circuit eliminates the need to monitor battery voltage, thereby
minimizing switching transients. The RF3166 requires no external routing or external components, simplifying layout and reducing board space.
Ordering Information
RF3166
Quad-Band GSM850/GSM900/DCS/PCS Power Amp Module
RF3166 SB
Power Amp Module 5-Piece Sample Pack
RF3166PCBA-410 Fully Assembled Evaluation Board
RF3166ASMPCBA-410Fully Assembled Evaluation Board with Antenna Switch Module
9GaAs HBT
GaAs MESFET
InGaP HBT
Optimum Technology Matching® Applied
SiGe BiCMOS
Si BiCMOS
SiGe HBT
GaAs pHEMT
9Si CMOS
GaN HEMT
Si BJT
RF MICRO DEVICES®, RFMD®, Optimum Technology Matching®, Enabling Wireless Connectivity™, PowerStar®, POLARIS™ TOTAL RADIO™ and UltimateBlue™ are trademarks of RFMD, LLC. BLUETOOTH is a trademark 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.
Rev A3 DS061031
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or [email protected].
1 of 16
RF3166
Absolute Maximum Ratings
Parameter
Rating
Unit
Supply Voltage
-0.3 to +6.0
VDC
Power Control Voltage (VRAMP)
-0.3 to +2.2
V
Input RF Power
+10
dBm
Max Duty Cycle
50
%
Output Load VSWR
10:1
Operating Case Temperature
-20 to +85
°C
Storage Temperature
-55 to +150
°C
Parameter
Min.
Specification
Typ.
Max.
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 performance or functional operation of the device under Absolute Maximum Rating conditions 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 application circuitry and specifications at any time without prior notice.
Unit
Condition
Overall Power Control
VRAMP
Power Control “ON”
2.1
Power Control “OFF”
0.26
VRAMP Input Capacitance
2
VRAMP Input Current
TX Enable “ON”
Max. POUT, Voltage supplied to the input
V
Min. POUT, Voltage supplied to the input
20
pF
DC to 2MHz
30
μA
VRAMP =2.1V
0.5
V
0.5
V
1.5
V
TX Enable “OFF”
GSM Band Enable
DCS/PCS Band Enable
V
1.5
V
Overall Power Supply
Power Supply Voltage
3.5
V
Specifications
3.0
4.5
V
Nominal operating limits
4.5
5.5
V
VRAMP <1.7V
μA
PIN <-30dBm, TX Enable=Low,
Temp=-20°C to +85°C
mA
VRAMP =0.26V, TX Enable=High
Power Supply Current
1
150
Overall Control Signals
Band Select “Low”
0
0
0.5
V
Band Select “High”
1.5
2.0
3.0
V
20
50
μA
TX Enable “Low”
0
0
0.5
V
TX Enable “High”
1.5
2.0
3.0
V
1
2
μA
Band Select “High” Current
TX Enable “High” Current
2 of 16
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or [email protected].
Rev A3 DS061031
RF3166
Parameter
Min.
Specification
Typ.
Max.
Unit
Condition
Temp=+25 °C, VBATT =3.5V,
VRAMP =2.1V, PIN =3dBm,
Freq=824MHz to 849MHz,
25% Duty Cycle, Pulse Width=1154μs
Overall (GSM850 Mode)
Operating Frequency Range
824 to 849
Maximum Output Power 1
34.2
Maximum Output Power 2
32.0
Total Efficiency
MHz
dBm
dBm
Temp=+85°C, VBATT =3.0V, VRAMP =2.1V
45
52
0
+3
+5
dBm
Maximum output power guaranteed at minimum drive level
Output Noise Power
-85
-83
dBm
RBW=100kHz, 869MHz to 894MHz,
POUT < +34.2dBm
Forward Isolation 1
-45
-30
dBm
TXEnable=Low, PIN =+5dBm
Forward Isolation 2
-30
-10
dBm
TXEnable=High, PIN =+5dBm,
VRAMP =0.26V
Input Power Range
%
Temp=+25°C, VBATT =3.5V, VRAMP =2.1V
At POUT MAX, VBATT =3.5V
Cross Band Isolation at 2f0
-30
-20
dBm
VRAMP =0.26V to VRAMP_RP
Second Harmonic
-15
-10
dBm
VRAMP =0.26V to VRAMP_RP
Third Harmonic
-30
-15
dBm
VRAMP =0.26V to VRAMP_RP
-36
dBm
VRAMP =0.26V to 2.1V
All Other
Non-Harmonic Spurious
Input Impedance
Ω
50
Input VSWR
2.5:1
Output Load VSWR Stability
8:1
Spurious<-36dBm, RBW=3MHz
Set VRAMP where POUT <34.2dBm into 50Ω
load
Output Load VSWR Ruggedness
10:1
Set VRAMP where POUT <34.2dBm into 50Ω
load. No damage or permanent degradation to
part.
Output Load Impedance
50
Ω
Load impedance presented at RF OUT pad
55
dB
VRAMP =0.26V to 2.1V
Power Control VRAMP
Power Control Range
50
Transient Spectrum
-35
Transient Spectrum Under
Extreme Conditions
-23
dBm
VRAMP =VRAMP_RP
dBm
Temp=-20°C to +85°C, VBATT >3.0V.
Ramping shape same as for Condition:
Temp=25°C, VBATT =3.5V, VRAMP =VRAMP_RP
Power Degradation from
Nominal Conditions
5dBm to 14dBm
-4
+4
dB
14dBm to 32dBm
-2
+2
dB
VBATT =3.0V to 4.5V, Temp=-20°C to +85°C,
PIN =0dBm to 5dBm,
Relative to output power for condition:
VBATT =3.5V, PIN =+3dBm, Temp=25°C,
Freq=836.5MHz.
Output power variation measured at set VRAMP.
Notes:
VRAMP_RP =VRAMP set for 34.2dBm at nominal conditions.
Rev A3 DS061031
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or [email protected].
3 of 16
RF3166
Parameter
Min.
Specification
Typ.
Max.
Unit
Condition
Temp=+25 °C, VBATT =3.5V,
VRAMP =2.1V, PIN =3dBm,
Freq=880MHz to 915MHz,
25% Duty Cycle, Pulse Width=1154μs
Overall (GSM900 Mode)
Operating Frequency Range
880 to 915
Maximum Output Power 1
34.2
Maximum Output Power 2
32.0
MHz
dBm
dBm
Temp=+85°C, VBATT =3.0V, VRAMP =2.1V
Total Efficiency
51
56
Input Power Range
0
+3
+5
dBm
Maximum output power guaranteed at minimum drive level
-83
-80
dBm
RBW=100kHz, 925MHz to 935MHz,
POUT < +34.2dBm
-85
-83
dBm
RBW=100kHz, 935MHz to 960MHz,
POUT < +34.2dBm
Output Noise Power
%
Temp=+25°C, VBATT =3.5V, VRAMP =2.1V
At POUT MAX, VBATT =3.5V
Forward Isolation 1
-40
-30
dBm
TXEnable=Low, PIN =+5dBm
Forward Isolation 2
-30
-10
dBm
TXEnable=High, PIN =+5dBm,
VRAMP =0.26V
Cross Band Isolation 2f0
-30
-20
dBm
VRAMP =0.26V to VRAMP_RP
Second Harmonic
-15
-10
dBm
VRAMP =0.26V to VRAMP_RP
Third Harmonic
-30
-15
dBm
VRAMP =0.26V to VRAMP_RP
-36
dBm
VRAMP =0.26V to 2.1V
All Other
Non-Harmonic Spurious
Input Impedance
Ω
50
Input VSWR
2.5:1
Output Load VSWR Stability
8:1
Spurious<-36dBm, RBW=3MHz
Set VRAMP where POUT <34.2dBm into 50Ω
load
Output Load VSWR Ruggedness
10:1
Set VRAMP where POUT <34.2dBm into 50Ω
load. No damage or permanent degradation to
part.
Output Load Impedance
50
Ω
Load impedance presented at RF OUT pad
55
dB
VRAMP =0.26V to 2.1V
Power Control VRAMP
Power Control Range
50
Transient Spectrum
-35
Transient Spectrum Under
Extreme Conditions
-23
dBm
VRAMP =VRAMP_RP
dBm
Temp=-20°C to +85°C, VBATT >3.0V.
Ramping shape same as for Condition:
Temp=25°C, VBATT =3.5V, VRAMP =VRAMP_RP
Power Degradation from
Nominal Conditions
5dBm to 14dBm
-4
+4
dB
14dBm to 32dBm
-2
+2
dB
VBATT =3.0V to 4.5V, Temp=-20°C to +85°C,
PIN =0dBm to 5dBm,
Relative to output power for condition:
VBATT =3.5V, PIN =+3dBm, Temp=25°C,
Freq=897.5MHz.
Output power variation measured at set VRAMP.
Notes:
VRAMP_RP =VRAMP set for 34.2dBm at nominal conditions.
4 of 16
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or [email protected].
Rev A3 DS061031
RF3166
Parameter
Min.
Specification
Typ.
Max.
Unit
Condition
Temp=25°C, VBATT =3.5V,
VRAMP =2.1V, PIN =3dBm,
Freq=1710MHz to 1785MHz,
25% Duty Cycle, pulse width=1154μs
Overall (DCS Mode)
Operating Frequency Range
1710 to 1785
Maximum Output Power 1
32.0
Maximum Output Power 2
30.0
Total Efficiency
MHz
dBm
dBm
Temp=+85°C, VBATT =3.0V, VRAMP =2.1V
46
52
0
+3
+5
dBm
Output Noise Power
-85
-80
dBm
RBW=100kHz, 1805MHz to 1880MHz, POUT
< 32dBm
Forward Isolation 1
-40
-30
dBm
TXEnable=Low, PIN =+5dBm
Forward Isolation 2
-25
-10
dBm
TXEnable=High, VRAMP =0.26V,
PIN =+5dBm
Input Power Range
%
Temp=+25°C, VBATT =3.5V, VRAMP =2.1V
At POUT MAX, VBATT =3.5V
Maximum output power guaranteed at minimum drive level
Second Harmonic
-15
-10
dBm
VRAMP =0.26V to VRAMP_RP
Third Harmonic
-30
-15
dBm
VRAMP =0.26V to VRAMP_RP
-36
dBm
VRAMP =0.26V to 2.1V
All Other
Non-Harmonic Spurious
Input Impedance
Ω
50
Input VSWR
2.5:1
Output Load VSWR Stability
8:1
Spurious<-36dBm, RBW=3MHz
Set VRAMP where POUT <32dBm into 50Ω load
Output Load VSWR Ruggedness
10:1
Set VRAMP where POUT <32dBm into 50Ω load.
No damage or permanent degradation to part.
Output Load Impedance
50
Ω
Load impedance presented at RF OUT pad
50
dB
VRAMP =0.26V to 2.1V
Power Control VRAMP
Power Control Range
45
Transient Spectrum
-35
Transient Spectrum Under
Extreme Conditions
-23
dBm
VRAMP =VRAMP_RP
dBm
Temp=-20°C to +85°C, VBATT >3.0V.
Ramping shape same as for Condition:
Temp=25°C, VBATT =3.5V, VRAMP =VRAMP_RP
Power Degradation from
Nominal Conditions
0dBm to 15dBm
-4
+4
dB
15dBm to 30dBm
-2
+2
dB
VBATT =3.0V to 4.5V, Temp=-20°C to +85°C,
PIN =0dBm to 5dBm,
Relative to output power for condition:
VBATT =3.5V, PIN =+3dBm, Temp=25°C,
Freq=1747.5MHz.
Output power variation measured at set VRAMP.
Notes:
VRAMP_RP =VRAMP set for 32dBm at nominal conditions.
Rev A3 DS061031
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or [email protected].
5 of 16
RF3166
Parameter
Min.
Specification
Typ.
Max.
Unit
Condition
Temp=25°C, VBATT =3.5V,
VRAMP =2.1V, PIN =3dBm,
Freq=1850MHz to 1910MHz,
25% Duty Cycle, pulse width=1154μs
Overall (PCS Mode)
Operating Frequency Range
1850 to 1910
Maximum Output Power 1
32.0
Maximum Output Power 2
30.0
Total Efficiency
MHz
dBm
dBm
Temp=+85°C, VBATT =3.0V, VRAMP =2.1V
46
52
0
+3
+5
dBm
Output Noise Power
-85
-80
dBm
RBW=100kHz, 1930MHz to 1990MHz, POUT
< 32dBm
Forward Isolation 1
-35
-30
dBm
TXEnable=Low, PIN =+5dBm
Forward Isolation 2
-25
-10
dBm
TXEnable=High, VRAMP =0.26V,
PIN =+5dBm
Input Power Range
%
Temp=+25°C, VBATT =3.5V, VRAMP =2.1V
At POUT MAX, VBATT =3.5V
Maximum output power guaranteed at minimum drive level
Second Harmonic
-15
-10
dBm
VRAMP =0.26V to VRAMP_RP
Third Harmonic
-30
-15
dBm
VRAMP =0.26V to VRAMP_RP
-36
dBm
VRAMP =0.26V to 2.1V
All Other
Non-Harmonic Spurious
Input Impedance
Ω
50
Input VSWR
2.5:1
Output Load VSWR Stability
8:1
Spurious<-36dBm, RBW=3MHz
Set VRAMP where POUT <32dBm into 50Ω load
Output Load VSWR Ruggedness
10:1
Set VRAMP where POUT <32dBm into 50Ω load.
No damage or permanent degradation to part.
Output Load Impedance
50
Ω
Load impedance presented at RF OUT pad
50
dB
VRAMP =0.26V to 2.1V
Power Control VRAMP
Power Control Range
45
Transient Spectrum
-35
Transient Spectrum Under
Extreme Conditions
-23
dBm
VRAMP =VRAMP_RP
dBm
Temp=-20°C to +85°C, VBATT >3.0V.
Ramping shape same as for Condition:
Temp=25°C, VBATT =3.5V, VRAMP =VRAMP_RP
Power Degradation from
Nominal Conditions
0dBm to 15dBm
-4
+4
dB
15dBm to 30dBm
-2
+2
dB
VBATT =3.0V to 4.5V, Temp=-20°C to +85°C,
PIN =0dBm to 5dBm,
Relative to output power for condition:
VBATT =3.5V, PIN =+3dBm, Temp=25°C,
Freq=1880MHz.
Output power variation measured at set VRAMP.
Notes:
VRAMP_RP =VRAMP set for 32dBm at nominal conditions.
6 of 16
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or [email protected].
Rev A3 DS061031
RF3166
Pin
1
2
Function
Description
DCS/PCS IN RF input to the DCS band. This is a 50Ω input.
BAND SELECT
Allows external control to select the GSM or DCS band with a logic high or
low. A logic low enables the GSM band whereas a logic high enables the
DCS band.
Interface Schematic
BAND SEL
GSMCTRL
TX EN
DCS CTRL
3
TX ENABLE
This signal enables the PA module for operation with a logic high.
VBATT
TX EN
4
5
6
VBATT
GND
VRAMP
TX ON
Power supply for the module. This should be connected to the battery.
Ramping signal from DAC. A 300kHz lowpass filter is integrated into the
CMOS. No external filtering is required.
300 kH z
VRAMP
7
8
GSM IN
GSM OUT
9
DCS/PCS
OUT
GND
Pkg
Base
Rev A3 DS061031
RF input to the GSM band. This is a 50Ω input.
RF output for the GSM band. This is a 50Ω output. The output load line
matching is contained internal to the package.
RF output for the DCS band. This is a 50Ω output. The output load line
matching is contained internal to the package.
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or [email protected].
7 of 16
RF3166
Package Drawing
1.40
1.25
1
6.00
± 0.10
0.450
± 0.075
6.00 ± 0.10
5.435 TYP
5.500 TYP
5.900 TYP
2.600 TYP
4.650
Dimensions in mm.
0.000 TYP
0.565 TYP
1.150 TYP
2.000 TYP
2.850
5.057
5.100
5.823
5.500
5.400 TYP
5.225 TYP
5.200 TYP
4.625 TYP
4.450 TYP
3.850 TYP
3.675 TYP
3.075 TYP
2.900 TYP
2.300 TYP
2.125 TYP
1.525 TYP
1.350 TYP
0.800 TYP
0.600 TYP
0.500 TYP
0.000
0.100 TYP
0.565 TYP
0.965
1.150 TYP
1.225 TYP
1.750 TYP
Shaded areas represent pin 1.
1
5.900 TYP
5.435
5.370
5.035
4.600
4.300
4.200
3.800
3.400
3.065
3.000
2.600
2.100
1.700
1.365
1.300
0.900 TYP
0.750 TYP
0.565 TYP
0.100 TYP
Pin Out
Top Down View
DCS/PCS
1
RFIN
9
DCS/PCS
RFOUT
8
GSM
RFOUT
BAND SELECT 2
TX ENABLE 3
VBATT 4
GND 5
VRAMP 6
GSM
7
RF IN
8 of 16
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or [email protected].
Rev A3 DS061031
RF3166
Application Schematic
DCS/PCS IN
50 Ω μstrip
1
BAND SELECT
9
50 Ω μstrip
DCS/PCS OUT
2
TX ENABLE
3
VBATT
4
5
VRAMP
GSM IN
50 Ω μstrip
6
7
8
50 Ω μstrip
GSM OUT
Evaluation Board Schematic
P1
1
GND P2-1
CON1
P2
1
VCC
CON1
50 Ω μstrip
DCS/PCS IN
50 Ω μstrip
1
BAND SELECT
9
DCS/PCS OUT
2
TX ENABLE
3
VBATT
4
22 μF*
VRAMP
5
6
50 Ω μstrip
7
50 Ω μstrip
8
GSM OUT
GSM IN
Notes:
* The value of the VBATT decoupling capacitor depends on the noise level of the phone board.
Capacitor type may be either tantalum or ceramic. Some applications may not require this capacitor.
1. All the PA output measurements are referenced to the PA output pad (pins 8 and 9).
2. The 50 Ω μstrip between the PA output pad and the SMA connector has an approximate insertion loss
of 0.1 dB for GSM850/EGSM900 and 0.2 dB for DCS1800/PCS1900 bands.
Rev A3 DS061031
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or [email protected].
9 of 16
RF3166
Evaluation Board Layout
Board Size 2.0” x 2.0”
Board Thickness 0.032”, Board Material FR-4, Multi-Layer
10 of 16
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or [email protected].
Rev A3 DS061031
RF3166
Theory of Operation
Overview
The RF3166 is a quad-band GSM850, EGSM900, DCS1800, and PCS1900 power amplifier module that incorporates an indirect closed loop method of power control. This simplifies the phone design by eliminating the need for the complicated control
loop design. The indirect closed loop appears as an open loop to the user and can be driven directly from the DAC output in the
baseband circuit.
Theory of Operation
The indirect closed loop is essentially a closed loop method of power control that is invisible to the user. Most power control
systems in GSM sense either forward power or collector/drain current. The RF3166 does not use a power detector. A highspeed control loop is incorporated to regulate the collector voltage of the amplifier while the stage are held at a constant bias.
The VRAMP signal is multiplied by a factor of 2.3 and the collector voltage for all three stages is regulated to the multiplied
VRAMP voltage. The basic circuit is shown in the following diagram.
VBATT
+
VRAMP
+
3 dB BW
300 kHz
Saturation
Detector
H(s)
RF IN
RF OUT
TX ENABLE
By regulating the power, the stages are held in saturation across all power levels. As the required output power is decreased
from full power down to 0dBm, the collector voltage is also decreased. This regulation of output power is demonstrated in
Equation 1 where the relationship between collector voltage and output power is shown. Although load impedance affects output power, supply fluctuations are the dominate mode of power variations. With the RF3166 regulating collector voltage, the
dominant mode of power fluctuations is eliminated.
2
( 2 ⋅ V CC – V SAT )
P dBm = 10 ⋅ log ------------------------------------------–3
8 ⋅ R LOAD ⋅ 10
(Eq. 1)
There are several key factors to consider in the implementation of a transmitter solution for a mobile phone. Some of them are:
•
•
•
•
•
•
•
•
•
•
Current draw and system efficiency
Power variation due to Supply Voltage
Power variation due to frequency
Power variation due to temperature
Input impedance variation
Noise power
Loop stability
Loop bandwidth variations across power levels
Burst timing and transient spectrum trade offs
Harmonics
Rev A3 DS061031
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or [email protected].
11 of 16
RF3166
Output power does not vary due to supply voltage under normal operating conditions if VRAMP is sufficiently lower than VBATT.
By regulating the collector voltage to the PA the voltage sensitivity is essentially eliminated. This covers most cases where the
PA will be operated. However, as the battery discharges and approaches its lower power range the maximum output power
from the PA will also drop slightly. In this case it is important to also decrease VRAMP to prevent the power control from inducing
switching transients. These transients occur as a result of the control loop slowing down and not regulating power in accordance with VRAMP.
The switching transients due to low battery conditions are regulated by the VBATT tracking circuit. The VBATT tracking circuit consists of a feedback loop that detects FET saturation. As the FET approaches saturation, the limiter adjusts the VRAMP voltage in
order to ensure minimum switching transients. The VBATT tracking circuit is integrated into the CMOS controller and requires no
additional input from the user.
Due to reactive output matches, there are output power variations across frequency. There are a number of components that
can make the effects greater or less. Power variation straight out of the RF3166 is shown in the tables below.
The components following the power amplifier often have insertion loss variation with respect to frequency. Usually, there is
some length of microstrip that follows the power amplifier. There is also a frequency response found in directional couplers
due to variation in the coupling factor over frequency, as well as the sensitivity of the detector diode. Since the RF3166 does
not use a directional coupler with a diode detector, these variations do not occur.
Input impedance variation is found in most GSM power amplifiers. This is due to a device phenomena where CBE and CCB (CGS
and CSG for a FET) vary over the bias voltage. The same principle used to make varactors is present in the power amplifiers.
The junction capacitance is a function of the bias across the junction. This produces input impedance variations as the Vapc
voltage is swept. Although this could present a problem with frequency pulling the transmit VCO off frequency, most synthesizer designers use very wide loop bandwidths to quickly compensate for frequency variations due to the load variations presented to the VCO.
The RF3166 presents a very constant load to the VCO. This is because all stages of the RF3166 are run at constant bias. As a
result, there is constant reactance at the base emitter and base collector junction of the input stage to the power amplifier.
Noise power in PA's where output power is controlled by changing the bias voltage is often a problem when backing off of output power. The reason is that the gain is changed in all stages and according to the noise formula (Equation 2),
F3 – 1
– 1- + --------------------------------F TOT = F1 + F2
G1 ⋅ G2
G1
(Eq. 2)
the noise figure depends on noise factor and gain in all stages. Because the bias point of the RF3166 is kept constant the gain
in the first stage is always high and the overall noise power is not increased when decreasing output power.
Power control loop stability often presents many challenges to transmitter design. Designing a proper power control loop
involves trade-offs affecting stability, transient spectrum and burst timing.
In conventional architectures the PA gain (dB/ V) varies across different power levels, and as a result the loop bandwidth also
varies. With some power amplifiers it is possible for the PA gain (control slope) to change from 100dB/V to as high as
1000dB/V. The challenge in this scenario is keeping the loop bandwidth wide enough to meet the burst mask at low slope
regions which often causes instability at high slope regions.
The RF3166 loop bandwidth is determined by internal bandwidth and the RF output load and does not change with respect to
power levels. This makes it easier to maintain loop stability with a high bandwidth loop since the bias voltage and collector voltage do not vary.
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support, contact RFMD at (+1) 336-678-5570 or [email protected].
Rev A3 DS061031
RF3166
An often overlooked problem in PA control loops is that a delay not only decreases loop stability it also affects the burst timing
when, for instance the input power from the VCO decreases (or increases) with respect to temperature or supply voltage. The
burst timing then appears to shift to the right especially at low power levels. The RF3166 is insensitive to a change in input
power and the burst timing is constant and requires no software compensation.
Switching transients occur when the up and down ramp of the burst is not smooth enough or suddenly changes shape. If the
control slope of a PA has an inflection point within the output power range or if the slope is simply too steep it is difficult to prevent switching transients. Controlling the output power by changing the collector voltage is as earlier described based on the
physical relationship between voltage swing and output power. Furthermore all stages are kept constantly biased so inflection
points are nonexistent.
Harmonics are natural products of high efficiency power amplifier design. An ideal class “E” saturated power amplifier will produce a perfect square wave. Looking at the Fourier transform of a square wave reveals high harmonic content. Although this is
common to all power amplifiers, there are other factors that contribute to conducted harmonic content as well. With most
power control methods a peak power diode detector is used to rectify and sense forward power. Through the rectification process there is additional squaring of the waveform resulting in higher harmonics. The RF3166 address this by eliminating the
need for the detector diode. Therefore the harmonics coming out of the PA should represent the maximum power of the harmonics throughout the transmit chain. This is based upon proper harmonic termination of the transmit port. The receive port
termination on the T/R switch as well as the harmonic impedance from the switch itself will have an impact on harmonics.
Should a problem arise, these terminations should be explored.
Rev A3 DS061031
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support, contact RFMD at (+1) 336-678-5570 or [email protected].
13 of 16
RF3166
PCB Design Requirements
PCB Surface Finish
The PCB surface finish used for RFMD’s qualification process is electroless nickel, immersion gold. Typical thickness is 3μinch
to 8μinch gold over 180μinch nickel.
PCB Land Pattern Recommendation
PCB land patterns are based on IPC-SM-782 standards when possible. The pad pattern shown has been developed and tested
for optimized assembly at RFMD; however, it may require some modifications to address company specific assembly processes. The PCB land pattern has been developed to accommodate lead and package tolerances.
PCB Metal Land Pattern
A = 0.55 x 0.95
B = 0.55 Sq. Typ.
C = 0.95 x 0.55 Typ.
D = 1.80 x 4.62
E = 0.60 Sq. Typ.
B
C
Dimensions in mm.
5.60
5.40
4.90
5.20
TYP
Pin 1
4.10
A
4.10
B
3.30
A
3.30
B
0.20
Metal Land Pattern
B
4.62
E
E
B
3.85
E
E
B
E
E
B
3.07
2.7
6
2.30
1.60
B
E
E
B
1.52
0.80
B
E
E
B
0.75
0.00
B
E
E
B
5.40
A
5.40
E
4.25
A
D
C
E
3.40
0.60
0.00
0.50
0.00
A
C
0.00
1.80
1.40
0.80
2.50
B
4.90
5.40
2.50
E
A
1.95
Pin 1
5.20
5.20
5.60
4.47
0.37
0.93
A = 0.40 Sq. Typ.
B = 0.80 x 0.40 Typ.
C = 0.40 x 0.80
Solder Mask Pattern
Figure 1. PCB Metal Land and Solder Mask Patterns (Top View)
PCB Solder Mask Pattern
Liquid Photo-Imageable (LPI) solder mask is recommended. The solder mask footprint will match what is shown for the PCB
metal land pattern with a 2mil to 3mil expansion to accommodate solder mask registration clearance around all pads. The
center-grounding pad shall also have a solder mask clearance. Expansion of the pads to create solder mask clearance can be
provided in the master data or requested from the PCB fabrication supplier.
Thermal Pad and Via Design
Thermal vias are required in the PCB layout to effectively conduct heat away from the package. The via pattern has been
designed to address thermal, power dissipation and electrical requirements of the device as well as accommodating routing
strategies.
The via pattern used for the RFMD qualification is based on thru-hole vias with 0.203mm to 0.330mm finished hole size on a
0.5mm to 1.2mm grid pattern with 0.025mm plating on via walls. If micro vias are used in a design, it is suggested that the
quantity of vias be increased by a 4:1 ratio to achieve similar results.
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support, contact RFMD at (+1) 336-678-5570 or [email protected].
Rev A3 DS061031
RF3166
Rev A3 DS061031
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or [email protected].
15 of 16
RF3166
16 of 16
7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical
support, contact RFMD at (+1) 336-678-5570 or [email protected].
Rev A3 DS061031