B GS 12S N 6
Per for man ce of S PD T R F Swi t c h
Ultr a L ow Inser tion Los s Wi de band R F
SP DT fo r U MT S, W CD M A an d LT E
diversit y or Wi Fi a p plic atio ns
Applic atio n N ote A N 332
Revision: Rev. 1.0
2015-01-19
RF and P r otecti on D evi c es
Edition 2015-03-25
Published by
Infineon Technologies AG
81726 Munich, Germany
© 2015 Infineon Technologies AG
All Rights Reserved.
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NOTE MUST VERIFY ANY FUNCTION DESCRIBED HEREIN IN THE REAL APPLICATION. INFINEON
TECHNOLOGIES HEREBY DISCLAIMS ANY AND ALL WARRANTIES AND LIABILITIES OF ANY KIND
(INCLUDING WITHOUT LIMITATION WARRANTIES OF NON-INFRINGEMENT OF INTELLECTUAL
PROPERTY RIGHTS OF ANY THIRD PARTY) WITH RESPECT TO ANY AND ALL INFORMATION GIVEN IN
THIS APPLICATION NOTE.
Information
For further information on technology, delivery terms and conditions and prices, please contact the nearest
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BGS12SN6
Ultra Low Insertion Loss Wideband Applications
Application Note AN332
Revision History: 2015-01-19
Previous Revision: prev. Rev. 0.0
Page
Subjects (major changes since last revision)
Updated text
Trademarks of Infineon Technologies AG
AURIX™, C166™, CanPAK™, CIPOS™, CIPURSE™, EconoPACK™, CoolMOS™, CoolSET™,
CORECONTROL™, CROSSAVE™, DAVE™, DI-POL™, EasyPIM™, EconoBRIDGE™, EconoDUAL™,
EconoPIM™, EconoPACK™, EiceDRIVER™, eupec™, FCOS™, HITFET™, HybridPACK™, I²RF™,
ISOFACE™, IsoPACK™, MIPAQ™, ModSTACK™, my-d™, NovalithIC™, OptiMOS™, ORIGA™,
POWERCODE™, PRIMARION™, PrimePACK™, PrimeSTACK™, PRO-SIL™, PROFET™, RASIC™,
ReverSave™, SatRIC™, SIEGET™, SINDRION™, SIPMOS™, SmartLEWIS™, SOLID FLASH™,
TEMPFET™, thinQ!™, TRENCHSTOP™, TriCore™.
Other Trademarks
Advance Design System™ (ADS) of Agilent Technologies, AMBA™, ARM™, MULTI-ICE™, KEIL™,
PRIMECELL™, REALVIEW™, THUMB™, µVision™ of ARM Limited, UK. AUTOSAR™ is licensed by
AUTOSAR development partnership. Bluetooth™ of Bluetooth SIG Inc. CAT-iq™ of DECT Forum.
COLOSSUS™, FirstGPS™ of Trimble Navigation Ltd. EMV™ of EMVCo, LLC (Visa Holdings Inc.). EPCOS™
of Epcos AG. FLEXGO™ of Microsoft Corporation. FlexRay™ is licensed by FlexRay Consortium.
HYPERTERMINAL™ of Hilgraeve Incorporated. IEC™ of Commission Electrotechnique Internationale. IrDA™
of Infrared Data Association Corporation. ISO™ of INTERNATIONAL ORGANIZATION FOR
STANDARDIZATION. MATLAB™ of MathWorks, Inc. MAXIM™ of Maxim Integrated Products, Inc.
MICROTEC™, NUCLEUS™ of Mentor Graphics Corporation. MIPI™ of MIPI Alliance, Inc. MIPS™ of MIPS
Technologies, Inc., USA. muRata™ of MURATA MANUFACTURING CO., MICROWAVE OFFICE™ (MWO) of
Applied Wave Research Inc., OmniVision™ of OmniVision Technologies, Inc. Openwave™ Openwave Systems
Inc. RED HAT™ Red Hat, Inc. RFMD™ RF Micro Devices, Inc. SIRIUS™ of Sirius Satellite Radio Inc.
SOLARIS™ of Sun Microsystems, Inc. SPANSION™ of Spansion LLC Ltd. Symbian™ of Symbian Software
Limited. TAIYO YUDEN™ of Taiyo Yuden Co. TEAKLITE™ of CEVA, Inc. TEKTRONIX™ of Tektronix Inc.
TOKO™ of TOKO KABUSHIKI KAISHA TA. UNIX™ of X/Open Company Limited. VERILOG™, PALLADIUM™
of Cadence Design Systems, Inc. VLYNQ™ of Texas Instruments Incorporated. VXWORKS™, WIND RIVER™
of WIND RIVER SYSTEMS, INC. ZETEX™ of Diodes Zetex Limited.
Last Trademarks Update 2011-11-11
Application Note AN332, Rev. 1.0
3 / 27
2015-01-19
BGS12SN6
Ultra Low Insertion Loss Wideband Applications
List of Content, Figures and Tables
Table of Content
1
Introduction ........................................................................................................................................ 6
2
2.1
2.2
2.3
2.4
BGS12SN6 Features .......................................................................................................................... 6
Main Features ...................................................................................................................................... 6
Functional Diagram .............................................................................................................................. 7
Pin Configuration .................................................................................................................................. 7
Pin Description ..................................................................................................................................... 7
3
3.1
3.2
Application .......................................................................................................................................... 8
Band Selection with RF CMOS Switch in Single-Ended Configuration ............................................... 8
Application Board ............................................................................................................................... 10
4
4.1
4.2
4.3
4.4
4.5
4.6
4.7
Small Signal Characteristics ........................................................................................................... 12
Measurement Results ........................................................................................................................ 12
Forward Transmission (measured on application board)................................................................... 13
Forward Transmission (probe measurements on device pads) ......................................................... 14
Wideband reflection RFin Port ........................................................................................................... 14
Wideband reflection RF Ports ............................................................................................................ 15
Wideband isolation RF1 ..................................................................................................................... 15
Wideband isolation RF2 ..................................................................................................................... 16
5
Intermodulation ................................................................................................................................ 17
6
Harmonic Generation ....................................................................................................................... 20
7
Power Compression Measurements on all RF Paths ................................................................... 23
8
8.1
8.2
8.3
Switching time .................................................................................................................................. 24
Measurement Specifications .............................................................................................................. 24
Measurement Setup ........................................................................................................................... 24
Measurement results .......................................................................................................................... 25
9
Authors .............................................................................................................................................. 26
List of Figures
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
Figure 10
Figure 11
Figure 12
Figure 13
Figure 14
Figure 15
Figure 16
Figure 17
Figure 18
Figure 19
Figure 20
Figure 21
Figure 22
Figure 23
BGS12SN6 Functional Diagram .......................................................................................................... 7
Pin configuration................................................................................................................................... 7
PCS/IMT band switching ...................................................................................................................... 8
LTE Band -1/Band -4 switching............................................................................................................ 8
3.5 GHz WiMAX (IEEE 802.16e) transceiver system .......................................................................... 9
Dual-band (2.4–6.0 GHz) WLAN (IEEE 802.11a/b/g/n), also MIMO applications ............................... 9
Layout of the application board .......................................................................................................... 10
Layout of de-embedding boards and single SMA connector ............................................................. 10
Forward transmission in order to measurement method ................................................................... 11
PCB layer information ........................................................................................................................ 11
Forward Transmission Curves of all RF Ports for LB and HB frequency range ................................ 13
Forward Transmission Curves of all RF Ports for HB and WLAN frequency range .......................... 13
Wideband Forward Transmission Curves of all RF Ports .................................................................. 14
Reflction RFin Port (50 MHz to 6 GHz) .............................................................................................. 14
Reflction RFin Port (50 MHz to 6 GHz) .............................................................................................. 15
Isolation RF1 (50 MHz to 6 GHz) ....................................................................................................... 15
Isolation RF2 (50 MHz to 6 GHz) ....................................................................................................... 16
Block diagram of RF Switch intermodulation ..................................................................................... 17
Test set-up for IMD Measurements for low power blocker signals .................................................... 18
Test set-up for IMD Measurements for medium and high power blocker signals .............................. 18
IMD2 and IMD3 results for Band I ...................................................................................................... 19
IMD Results for Band V ...................................................................................................................... 19
Set-up for harmonics measurement ................................................................................................... 20
Application Note AN332, Rev. 1.0
4 / 27
2015-01-19
BGS12SN6
Ultra Low Insertion Loss Wideband Applications
List of Content, Figures and Tables
Figure 24
Figure 25
Figure 26
Figure 27
Figure 28
Figure 29
Figure 30
Figure 31
nd
2 harmonic at fc=824 MHz ............................................................................................................... 21
rd
3 harmonic at fc=824 MHz ................................................................................................................ 21
nd
2 Harmonic at fc=1800 MHz............................................................................................................. 22
rd
3 Harmonic at fc=1800 MHz ............................................................................................................. 22
Power Compression Measurement Results at fc=824 MHz, 1700 MHz and 2600MHz ..................... 23
Switching Time and Rise/Fall Time .................................................................................................... 24
Switching Time Measurement Setup ................................................................................................. 24
Screenshots of Switching Time Measurement BGS12SN6 .............................................................. 25
List of Tables
Table 1
Table 2
Table 3
Table 4
Table 5
Table 6
Table 7
Table 8
Pin Description (top view) .................................................................................................................... 7
Forward Transmission from RFIN Port to the Respective RF Port (dB) ............................................ 12
Reflection RFin Port to the Respective RF Port (dB) ........................................................................ 12
Reflection RF Port to the Respective RF Port (dB) ............................................................................ 12
Isolation RF1 (off state) to RF2 and RFin (dB) .................................................................................. 12
Isolation RF2 (off state) to RF1 and RFin (dB) .................................................................................. 12
Test conditions and specifications of IMD measurements ................................................................. 17
Switching time measurement results ................................................................................................. 25
Application Note AN332, Rev. 1.0
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2015-01-19
BGS12SN6
Ultra Low Insertion Loss Wideband Applications
Introduction
1
Introduction
The BGS12SN6 RF MOS switch is designed for mid power and pre PA applications. Any of the 2 ports can be
used as termination of the diversity antenna or Wifi application handling up to 30 dBm.
This single supply chip integrates on-chip CMOS logic driven by a simple, single-pin CMOS or TTL compatible
control input signal. The 0.1 dB compression point exceeds the switch’s maximum input power level of 32 dBm,
resulting in linear performance at all signal levels. The RF switch has a very low insertion loss of 0.26 dB in the
Low Band (LB), 0.29 dB in the Mid Band (MB) and High Band (HB) and 0.56 dB in the 5GHz range (measured
directly with probes on the package).
Unlike GaAs technology, external DC blocking capacitors at the RF ports are only required if DC voltage is
applied externally.
The BGS12SN6 RF switch is manufactured in Infineon’s patented MOS technology, offering the performance of
GaAs with the economy and integration of conventional CMOS including the inherent higher ESD robustness.
2
BGS12SN6 Features
2.1
Main Features

2 high-linearity TRx paths with power handling capability of up to 30 dBm

High switching speed, ideal for WLAN and Bluetooth applications

All ports fully symmetrical

No external decoupling components required

Very low insertion loss up to 6 GHz

Low harmonic generation

High port-to-port-isolation

0.1 to 6 GHz coverage

High ESD robustness

On-chip control logic

Very small leadless and halogen free package TSLP-6-2 (0.7x1.1mm )
with super low height of 0.31 mm

RoHS compliant package
2
Application Note AN332, Rev. 1.0
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2015-01-19
BGS12SN6
Ultra Low Insertion Loss Wideband Applications
BGS12SN6 Features
2.2
Functional Diagram
Pass through
to RF1
RFin
RF1
RF2
Isolation
to Ground
GND
Decoder
+ESD
Vdd
Figure 1
Ctrl
Application specific funcional
diagram for RF1 active
BGS12SN6 Functional Diagram
The functional Diagram in Figure 1 shows a typical bahaviour of the BGS12SN6 in active state, meaning RF1
active and RF2 in isolation mode. This Daigram gives a short brief about the working princip of this SPDT. The
BGS12SN6 in designed by an implementation of several series and shunt transistors to ground to optimize the
RF signal parameter in points of isolations between active and non-active ports and the RF power capability of
32 dBm in maximum ratings.
2.3
Pin Configuration
In Figure 2 the pin configuration in top view is given.
Figure 2
Pin configuration
2.4
Pin Description
Table 1
Pin Description (top view)
Pin NO
Name
Pin Type
Function
1
RF2
I/O
RF port 2
2
GND
GND
3
RF1
I/O
4
Vdd
PWR
5
RFIN
I/O
RF port In
6
CTRL
I
Control Pin
Application Note AN332, Rev. 1.0
7 / 27
Ground
RF port 1
Supply Voltage
2015-01-19
BGS12SN6
Ultra Low Insertion Loss Wideband Applications
Application
3
Application
3.1
Band Selection with RF CMOS Switch in Single-Ended Configuration
The number of LTE bands to support in a mobile phone is increasing rapidly worldwide. A simple way to support
more bands in a mobile phone is to implement band selection function by adding a RF CMOS switch to existing
transceiver/diversity ICs. Following two examples show band selection with the BGS12SN6, switching in singleended configuration, a WiMAX FE system and a typical WLAN Dual Band application using the BGS12SN6 as
RF switch.
UMTS
PCS or IMT
GSM900 Rx
GSM1800 Rx
GSM1900 Rx
GSM850/900 Tx
PA
LPF
GSM1800/1900 Tx
RF Transceiver IC
GSM850 Rx
UMTS Cell
PCS
UMTS
SPDT
Switch
PCS or IMT
IMT
Figure 3
PCS/IMT band switching
Band 4
LNA
SPDT
Switch
Band 1
Figure 4
LTE
Transceiver
IC
LTE Band -1/Band -4 switching
Figure 3 and Figure 4 are typical examples of band switching in a phone or tablet for transmitting and receivien
path. Such an application, using BGS12SN6 as band selection switch supports a brider bandwith for data
transfer by adding an extra band at the transceivers to overcome the bottleneck to get higher data rates and
improve the system performance.
Application Note AN332, Rev. 1.0
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2015-01-19
BGS12SN6
Ultra Low Insertion Loss Wideband Applications
Application
WiMAX: 3.3 – 3.7 GHz
BPF
LNA
Balun
WiMAX
SPDT
Switch
Single/Dual Band
Power Detector
Transceiver IC
ESD
Diode
PA
BPF
Figure 5
Balun
3.5 GHz WiMAX (IEEE 802.16e) transceiver system
2.4 GHz LNA
Dual-Band WLAN:
2.4 – 6 GHz
RX Diplexer
RXg
RXa
SPDT
Switch
TX1
TX
Transceiver
IC
TXg
2.4 GHz PA
ESD
Diode
RX1
5 GHz LNA
RX
TX Diplexer
TXn
Figure 6
RXn
Power
Detector 5 GHz PA
TXa
Dual-band (2.4–6.0 GHz) WLAN (IEEE 802.11a/b/g/n), also MIMO applications
Thanks to the BGS12SN6 wideband RF performance, supporting a very lo insertion loss of around 0.4 dB to 0.7
dB upto 6 GHz, this SPDT is highly suitable for WiMAX (Figure 5) and WLAN (Figure 6) applications. Next to
this performance wise system key parameter, the BGS12SN6 has a very fast RF rise time of about 70 ns.
Application Note AN332, Rev. 1.0
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2015-01-19
BGS12SN6
Ultra Low Insertion Loss Wideband Applications
Application
3.2
Application Board
Below is a picture of the evaluation board used for the measurements (Figure 7). The board is designed so that
all connecting 50 Ohm lines have the same length.
In order to get accurate values for the insertion loss of the BGS12PL6 all influences and losses of the evaluation
board, lines and connectors have to be eliminated. Therefore a separate de-embedding board, representing the
line length is necessary (Figure 6). But be aware, this calibration/deembedding method is only working in a
proper way up to 3 to 4 GHz. Upper frequencies, and the resulting influence of the pcb transition to the coaxial
line of the SMA connector can not be deembedded in such a way.
The calibration of the network analyser (NWA) is done in severall steps:
- Perform full calibration on all NWA ports.
- Attach empty SMA connector (with cutted RF line, Figure 8, left) at port 2 and perform “open” port extension.
Turn port extensions on.
- Connect the “half” de-embedding board (Figure 8 left board) between port1 and port2, store this as a
s-parameter (s2p) file.
- Turn all port extentions off.
- Load the stored s-parameter file as de-embedding file for all used NWA ports
- Switch all port extentions on
- Check insertion loss with the de-embedding through board (Figure 8 right board)
In case, there is no NWA including this option for the deembedding available, please use the measured s2p file
as a deembedding structure in any RF simulation environment @ all ports of the measured application board
itself.
Figure 7
Layout of the application board
Figure 8
Layout of de-embedding boards and single SMA connector
Application Note AN332, Rev. 1.0
10 / 27
2015-01-19
BGS12SN6
Ultra Low Insertion Loss Wideband Applications
Application
Device level measurements above 4 GHz are not feasible with this deembeding method. The reason is a very
tiny resonance between 5 and 6 GHz. Behind this behavior is the transmission between the pcb RF trace and
the SMA coaxial line. The capacitance and the inductance are not sufficient enough to reproduce with the
deembedding method. A better way to improve the compensation of the pcb losses and phase shifts is to
perform a full open port extension with an empty application board including phase and losses. But, this is a
trade of for insertion loss measurement accuracy over frequency bandwith. That means, for lower frequencies
up to 3 or 4 Ghz the deembedding method is more ecactly, for higher frequencies the open port extension
method is more accurate, shown in Figure 9, because of fewer losses in kind of quality characteristics of the
connector to pcb transition, but limited by the number of points and the NWA’s interpolation.
As reference for the BGS12SN6 performance, probe measurements direclty on the package (brown and red
curve) pads are show the graph below.
Forward Transmission vs. measurement method
-0.2
-0.3
Proposed
Deembedding Method
freequency range
-0.4
[dB]
-0.5
Both Methods
acceptable
-0.6
-0.7
RF1_open_port_extension_method
RF2_open_port_extension_method
-0.8
Proposed Open Port
Extension Method
freequency range
RF1_probe_measuement
RF2_probe_measurement
-0.9
RF1_deembeding_method
RF2_deembedding_method
-1
0
2000
4000
6000
Frequency (MHz)
Figure 9
Forward transmission in order to measurement method
These small differences, depending on the measurement method, are only necessary for higly precise insertion
loss measurement concerning the neededcorrectness of some 1/10 rather 1/100 of dB.
The construction of the PCB is shown in Figure 10 and contains of 3 layers (35µm copper), one Signal RF
layer, and two ground layers meaning RF ground DC ground. The Rodgers material defines the RF
performance, the FR4 material is just use as a mechanical carrier in order to stability of the pcb.
Vias
Rodgers , 0.2mm
Copper
35µm
Figure 10
FR4, 0.7mm
PCB layer information
Application Note AN332, Rev. 1.0
11 / 27
2015-01-19
BGS12SN6
Ultra Low Insertion Loss Wideband Applications
Small Signal Characteristics
4
Small Signal Characteristics
The small signal characteristics are measured at room temperature (~25°C) with a Network analyzer including a
Multiport System on application board. The NWA is set to an input Power of 0dBm, a 50 MHz to 4 GHz
(measuring LB and MB) or 50 MHz to 6 GHz (measuring HB and WLAN) frequency range with an IF bandwith of
15 kHz. All ports are terminated with a 50 Ω load (provided from the measurement system directly) during the
measurement. Device specific, the Vdd is set to 3.3 volts and the Vctrl to 3 volts.
4.1
Measurement Results
In the following tables and graphs the most important RF parameter of the BGS12SN6 are shown. The markers
are set to the most important frequencies in Low Band (up to 1 GHz), Mid Band (over 1 GHz up to 3 GHz) and
1
2
High Band (3 GHz to 4 GHz) for mobile communication applications and Wireless LAN (5 GHz) .
Table 2
Forward Transmission from RFIN Port to the Respective RF Port (dB)
Low Band
Mid Band
High Band
WLAN
Frequency
(MHz)
824 915 1000 1575 1710 1910 2170 2400 2690 3400 3600 5200 5500 5800
RF1
RF2
Table 3
-0.26 -0.27 -0.27 -0.3 -0.31 -0.32 -0.34 -0.37 -0.38 -0.49 -0.5 -0.68 -0.77 -0.67
-0.27 -0.27 -0.28 -0.31 -0.32 -0.33 -0.36 -0.38 -0.41 -0.5 -0.52 -0.69 -0.76 -0.71
Reflection RFin Port to the Respective RF Port (dB)
Low Band
Mid Band
High Band
WLAN
Frequency
(MHz)
824 915 1000 1575 1710 1910 2170 2400 2690 3400 3600 5200 5500 5800
RF1
RF2
Table 4
-25.4 -24.8 -23.9 -20.6 -19.8 -19 -18.2 -17.6 -17 -15.4 -15.4 -18 -19.7 -20.9
-25.7 -24.9 -24.3 -21 -20.4 -19.8 -18.9 -18.4 -17.8 -16.1 -15.9 -17.9 -19.2 -20.1
Reflection RF Port to the Respective RF Port (dB)
Low Band
Mid Band
High Band
WLAN
Frequency
(MHz)
824 915 1000 1575 1710 1910 2170 2400 2690 3400 3600 5200 5500 5800
RF1
RF2
Table 5
Frequency
(MHz)
RF2
RFin
Table 6
Frequency
(MHz)
RF1
RFin
1
2
-26.2 -25.6 -24.7 -21 -20.2 -19.3 -18.3 -17.6 -16.9 -14.9 -14.9 -17.4 -18.7 -20.7
-25.4 -24.7 -24 -20.7 -20.2 -19.6 -18.8 -18.1 -17.4 -15.6 -15.6 -16.8 -17.7 -19
Isolation RF1 (off state) to RF2 and RFin (dB)
Low Band
824
915
1000
Mid Band
1575
1710
1910
2170
High Band
2400
2690
3400
3600
WLAN
5200
5500 5800
-46.5 -45.8 -44.7 -39.3 -38.7 -38.5 -35.3 -34.5 -33.5 -31 -29.3 -20.9 -20.8 -22.7
-41 -39.9 -39.2 -34.1 -33.5 -32.7 -30.6 -29.8 -28.9 -26.8 -25.6 -18.3 -18 -19.9
Isolation RF2 (off state) to RF1 and RFin (dB)
Low Band
824
915
1000
Mid Band
1575
1710
1910
2170
High Band
2400
2690
3400
3600
WLAN
5200
5500 5800
-46.1 -45.1 -44.2 -39.6 -38.6 -37.4 -36.1 -34.5 -34.2 -30.9 -29.2 -20.9 -21.4 -24.1
-40.5 -39.5 -38.7 -34.1 -33.1 -31.9 -30.3 -29 -27.7 -25.6 -24.9 -17.8 -17.2 -18.7
Measured with open port extension deembedding method
Measured with open port extension deembedding method
Application Note AN332, Rev. 1.0
12 / 27
2015-01-19
BGS12SN6
Ultra Low Insertion Loss Wideband Applications
Small Signal Characteristics
4.2
Forward Transmission (measured on application board)
Forward Transmission RF Ports for LB and MB
0
-0.5
[dB]
824 MHz
-0.2678 dB
915 MHz
-0.2738 dB
-1
2400 MHz
-0.3775 dB
1575 MHz
-0.3049 dB
1710 MHz
-0.3102 dB
2170 MHz
-0.3416 dB
2690 MHz
-0.3819 dB
1910 MHz
-0.3215 dB
1000 MHz
-0.2756 dB
-1.5
RF1
RF2
-2
0
1000
2000
3000
Frequency (MHz)
Figure 11
Forward Transmission Curves of all RF Ports for LB and HB frequency range
Forward Transmission RF Ports for HB and WLAN
0
3400 MHz
-0.4873 dB
3600 MHz
-0.5003 dB
[dB]
-0.5
5200 MHz
-0.6769 dB
-1
5500 MHz
-0.7571 dB
5900 MHz
-0.7371 dB
-1.5
RF1
RF2
-2
3000
5000
6000
Frequency (MHz)
Figure 12
Forward Transmission Curves of all RF Ports for HB and WLAN frequency range
Application Note AN332, Rev. 1.0
13 / 27
2015-01-19
BGS12SN6
Ultra Low Insertion Loss Wideband Applications
Small Signal Characteristics
4.3
Forward Transmission (probe measurements on device pads)
Wideband Foreward Transmission up to 6 Ghz
0
2170 MHz
-0.31 dB
1575 MHz
-0.29 dB
2400 MHz
-0.32 dB
824 MHz
-0.26 dB
-0.5
1910 MHz
-0.3 dB
915 MHz
-0.26 dB
1000 MHz 1710 MHz
-0.3 dB
-0.27 dB
5800 MHz
-0.63 dB
3400 MHz
-0.39 dB
2690 MHz
-0.34 dB
3600 MHz
-0.41 dB
5200 MHz
-0.55 dB
5500 MHz
-0.59 dB
-1
-1.5
RF1
RF2
-2
0
2000
4000
6000
Frequency (MHz)
Figure 13
Wideband Forward Transmission Curves of all RF Ports
4.4
Wideband reflection RFin Port
Reflection RFin Port
-10
3270 MHz
-15.25 dB
-15
[dB]
-20
-25
-30
RFin_RF1
RFin_RF2
-35
0
Figure 14
1000
2000
3000
4000
Frequency (MHz)
5000
6000
Reflction RFin Port (50 MHz to 6 GHz)
Application Note AN332, Rev. 1.0
14 / 27
2015-01-19
BGS12SN6
Ultra Low Insertion Loss Wideband Applications
Small Signal Characteristics
4.5
Wideband reflection RF Ports
Reflection RF Ports
-10
-15
-20
[dB]
3624 MHz
-14.78 dB
-25
-30
RF1
RF2
-35
0
2000
4000
6000
Frequency (MHz)
Figure 15
Reflction RFin Port (50 MHz to 6 GHz)
4.6
Wideband isolation RF1
Isolation_RF1
0
-20
-40
5461 MHz
-17.81 dB
-60
RF2_RF1
RF1_RFin
-80
0
2000
4000
6000
Frequency (MHz)
Figure 16
Isolation RF1 (50 MHz to 6 GHz)
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Ultra Low Insertion Loss Wideband Applications
Small Signal Characteristics
4.7
Wideband isolation RF2
Isolation_RF2
0
-20
-40
5479 MHz
-17.02 dB
-60
-80
RF1_RF2
RF2_RFin
-100
50
2050
4050
6000
Frequency (MHz)
Figure 17
Isolation RF2 (50 MHz to 6 GHz)
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Ultra Low Insertion Loss Wideband Applications
Intermodulation
5
Intermodulation
Another very important parameter of a RF switch is the large signal capability. One of the possible
intermodulation scenarios is shown in Figure 18. The transmission (Tx) signal from the main antenna is coupled
into the diversity antenna with with high power.This signal (20 dBm) and a received Jammer signal (-15 dBm)
are entering the switch.
Coupled Tx
Signal from
main antenna
Jammer
(CW)
Receiver
Diversity
Antenna
RF Switch
IMD
Figure 18
Block diagram of RF Switch intermodulation
Special combinations of TX and Jammer signal are producing intermodulation products 2
nd
rd
and 3 order, which
fall in the RX band and disturb the wanted RX signal.
In Error! Reference source not found. frequencies for 3 bands and the linearity specifications for an
undisturbed communication are given.
Table 7
Test conditions and specifications of IMD measurements
Band 1
TX
Testcase
FIN (MHz)
PIN (dBm) CW
IMD3
IMD2 low
IMD2 high
1950
10
Interferer
FIN (MHz)
PIN (dBm) CW
1760
190
-15
4090
IMD product
FIMD (MHz)
2140
Band 5
Testcase
FIN (MHz)
PIN (dBm) CW
IMD3
IMD2 low
IMD2 high
835
10
FIN (MHz)
790
45
1715
PIN (dBm) CW
FIMD (MHz)
-15
880
The test setup for the IMD measurements has to provide a very high isolation between RX and TX signals. As
an example the test set-up and the results for the high band are shown (Figure 19 and Figure 21).
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Ultra Low Insertion Loss Wideband Applications
Intermodulation
For the RX / TX separation a professional duplexer with 80 dB isolation is used.
In Figure 21 the results for High band are given. For each distortion scenario there is a min and a max value
given. This variation is caused by a phase shifter connected between switch and duplexer. In the test set-up the
phase shifter represents a no ideal matching of the switch to 50 Ohm.
Load
-20dB
-6 dB
IMD Product
reference Plane
Tx
Signal
Generator
Power
Amplifier
Circulator
Blocker
Signal
Duplexer
Tunable
Bandpass
Filter
-3 dB
ANT
Phase Shifter /
Delay Line
-6dB*
-20dB
DUT
Tx
ANT
Tunable
Bandpass
Filter
Signal
Generator
Rx
Signal
Analyzer
Figure 19
-6 dB
Power reference plane
regarding Specification
Test set-up for IMD Measurements for low power blocker signals
Load
-20dB
-6 dB
IMD Product
reference Plane
Tx
Signal
Generator
Power
Amplifier
Circulator
Blocker
Signal
Duplexer
Tunable
Bandpass
Filter
-3 dB
ANT
Phase Shifter /
Delay Line
DUT
Tx
-6 dB*
-20 dB
ANT
Tunable
Bandpass
Filter
Rx
Load
Signal
Analyzer
-6 dB
Power reference plane
regarding Specification
-20dB
Signal
Generator
Figure 20
Power
Amplifier
Circulator
Test set-up for IMD Measurements for medium and high power blocker signals
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BGS12SN6
Ultra Low Insertion Loss Wideband Applications
Intermodulation
Band 1 IMD
-95.00
-100.00
[dBm]
-105.00
-110.00
RF1
-115.00
RF2
-120.00
-125.00
Figure 21
IMD2 and IMD3 results for Band I
Band 5 IMD
-95.00
-100.00
[dBm]
-105.00
-110.00
-115.00
RF1
-120.00
RF2
-125.00
-130.00
Figure 22
IMD Results for Band V
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Ultra Low Insertion Loss Wideband Applications
Harmonic Generation
6
Harmonic Generation
Harmonic generation is another important parameter for the characterization of a RF switch. RF switches have
to deal with high RF levels, up to 33 dBm. With this high RF power at the input of the switch harmonics are
generated. These harmonics (2
nd
rd
and 3 ) can disturb the other reception bands or cause distortion in other RF
applications (GPS, WLan) within the mobile phone.
Load
-20dB
Directional
Coupler
-20dB
-3 dB
Signal
Generator
Power
Amplifier
Circulator
F = Ffundamantel
Lowpass Filter
Ffilter ≥ Ffundamental
A
measurement
Pin (Ffundamental)
Power meter
B
-3dB
measurement
Pout (Ffundamental)
DUT
Tx
-10dB
Signal
Analyzer
Highpass Filter
Ffundamental << Ffilter ≤ Fharmonics
Directional
Coupler
ANT
-3 dB
reference plane reference plane
Pout (Fharmonic and Pin (Ffundamental)
Ffundamental)
Figure 23
Set-up for harmonics measurement
nd
rd
The results for the harmonic generation at 824 MHZ are shown in Figure 24 (2 harmonic) and Figure 25 (3
harmonic) for all RF ports.
At the x-axis the input power is plotted and at the y- axis the generated harmonics in dBm.
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BGS12SN6
Ultra Low Insertion Loss Wideband Applications
Harmonic Generation
nd
Figure 24
2
harmonic at fc=824 MHz
Figure 25
3 harmonic at fc=824 MHz
rd
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Ultra Low Insertion Loss Wideband Applications
Harmonic Generation
nd
Figure 26
2
Harmonic at fc=1800 MHz
Figure 27
3 Harmonic at fc=1800 MHz
rd
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Ultra Low Insertion Loss Wideband Applications
Power Compression Measurements on all RF Paths
7
Power Compression Measurements on all RF Paths
To judge the large signal capability the power compression is a usual measurement tool. The output the power
is measured while increasing the input power. At a certain point the output power does not follow the input and
the switch compresses the RF signal. In the diagram below (Figure 28) the IL is plotted versus the injected input
power. The input power can be increased to 30 dBm and there is no compression visible on none of the RF
ports.
IL (dB)
BGS12SN6 P0.1dB
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
P0.1dB 824 Mhz
P0.1dB 1700 MHz
P0.1dB 2600 MHZ
20
22
24
26
28
30
32
Pin (dBm)
Figure 28
Power Compression Measurement Results at fc=824 MHz, 1700 MHz and 2600MHz
The measurements are done on Large Signal measurement setup which is not calibrated for Insertion Loss with
high precision. So the values here may differ with the actual IL values earlier in this report.
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Ultra Low Insertion Loss Wideband Applications
Switching time
8
Switching time
8.1
Measurement Specifications
Switching On/ Off Time: 50% Trigger signal to 90 % RF Signal / 50% Trigger signal to 10% RF Signal
Rise time / Fall time:
10% to 90% RF Signal / 90% to 10% RF Signal
VCTRL
2
VCTRL
tON
90% RF signal
RF signal
tOFF
10% RF signal
90% RF signal
RF signal
tOFF
tON
Figure 29
Switching Time and Rise/Fall Time
8.2
Measurement Setup
Figure 30
Switching Time Measurement Setup
Application Note AN332, Rev. 1.0
10% RF signal
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Ultra Low Insertion Loss Wideband Applications
Switching time
8.3
Measurement results
The switching Time measurement setup consist of one pulse generator which generates a sqare wave with 50%
duty cycle and an amplitude of 1.8 Volts, an oscilloscope which can detect the 1 GHz signal and the 1 kHz
signal and one Signal generator which is set to an output signal of 1GHz with a power level 10 dBm.
If the oscilloscope cannot detect the 1 GHz signal of the RF path, due to small bandwith, it is possible to use a
crystal oscillator in front of the oscilloscope (such a device detects any RF signal present at input and
commutates that) so that the RF signal can be detected.
Figure 31
Table 8
Screenshots of Switching Time Measurement BGS12SN6
Switching time measurement results
BGS12SN6
Application Note AN332, Rev. 1.0
RF rise time (ns)
Switching time (ns)
60
400
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Ultra Low Insertion Loss Wideband Applications
Authors
9
Authors
Andre Dewai, Senior Application Engineer of the Business Unit “RF and Protection Devices”
Ralph Kuhn, Senior Staff Application Engineer of the Business Unit “RF and Protection Devices”
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