AN3021
PIN Diodes for Microwave Switch Designs
Introduction
This Application Note is intended to provide practical guidance in the selection of PIN Diodes for switch control
circuit functions. Switches, Digital and Analog Attenuators, and Limiters each have unique functions that require
proper device selection. The design difficulty lies within the parametric translation from Diode Specifications, to
the circuit designers’ Microwave Specifications. Diode parametric language such as Vb, Vf, Ct, Rs,
τ
L
,
θ,
must
convert into Insertion Loss, VSWR, Isolation, P1dB, Input IP3, RF Operating Power, RF Power Dissipation, and
D.C. Power Consumption Specification Terminology.
In addition to actual diode parameters, package parasitics play a significant role in determining switch circuit per-
formance. Package capacitance, package inductance, package electrical resistance, and package thermal im-
pedance are extremely important considerations to determine the effective frequency bandwidth and maximum
incident power for reliable switch operation.
The manufacturing methodology dictates the type of diode selection. Surface mount assembly will mandate the
usage of either plastic, HMIC SURMOUNT, or MELF & HiPAX ceramic devices. Chip and Wire ( Hybrid ) manu-
facturing will determine the usage of Cermachips, Flip Chips, or Beam Lead Devices. Schematics for the most
common switch designs: Series-Exclusive, Shunt-Exclusive, and Series-Shunt are outlined below for considera-
tion.
Rev. V2
The Decision Making Process for PIN Diode Selection for Microwave Switch Design
The following procedure outlines and Effective Process for PIN Diode Selection for Switch Design.
1. Determine the Preferred Type of Manufacturing for the PIN Diode in the Switch Design: Surface
Mount or Chip and Wire (Hybrid) Manufacturing.
2. Determine the Frequency of Operation and RF Power Handling of the Switch Design.
3. Use Table 1, “Relative Switch Performance and Design Evaluation Matrix” to determine the Type of
Switch Design that Best Satisfies the Particular Switch Specifications and Requirements.
4. Use Table 2, “Relative PIN Diode Performance Evaluation Matrix” to Determine the Type of PIN Di-
ode that Best Satisfies the Switch Design Selected from Table 1.
5. Use Table 3, “PIN Diode P/N Series Matrix” to Determine the PIN Diode P/N Series that Best Satis-
fies the Type of PIN Diode Selected from Table 2.
1
ADVANCED:
Data Sheets contain information regarding a product M/A-COM Technology Solutions
•
North America
Tel: 800.366.2266 •
Europe
Tel: +353.21.244.6400
is considering for development. Performance is based on target specifications, simulated results,
•
India
Tel: +91.80.43537383
•
China
Tel: +86.21.2407.1588
and/or prototype measurements. Commitment to develop is not guaranteed.
Visit www.macomtech.com for additional data sheets and product information.
PRELIMINARY:
Data Sheets contain information regarding a product M/A-COM Technology
Solutions has under development. Performance is based on engineering tests. Specifications are
typical. Mechanical outline has been fixed. Engineering samples and/or test data may be available.
M/A-COM Technology Solutions Inc. and its affiliates reserve the right to make
Commitment to produce in volume is not guaranteed.
changes to the product(s) or information contained herein without notice.
AN3021
PIN Diodes for Microwave Switch Designs
Table 1: Relative Switch Performance and Design Evaluation Matrix
Switch Design Configuration
Parameter
Insertion Loss
VSWR
Isolation
P1dB
Input IP3
RF Incident Power
RF Power Dissipation
Switching Speed
D.C. Power Consumption
PIN Diode Driver Design Simplicity
RF Design Simplicity
Cost
Overall Evaluation
Rev. V2
Series Diodes Exclusive
Worst
Moderate
Worst
Moderate
Moderate
Worst
Worst
Worst
Best (Single +5 V)
Best (+5 V Only)
Best
Best
34 Points
Shunt Diodes Exclusive
Moderate
Worst
Moderate
Moderate
Moderate
Best
Best
Best
Moderate (+5 V, -5 V)
Moderate (+5 V, -5 V)
Worst
Moderate
38 Points
Series-Shunt Diodes
Best
Best
Best
Moderate
Moderate
Moderate
Moderate
Moderate
Worst (+5 V, -5 V)
Moderate (+5 V, -5 V)
Moderate
Moderate
40 Points
Notes:
Evaluation based upon following grading : Best = 5 Points, Moderate = 3 Points, Worst = 1 Point. The higher
the score, the better the overall relative design advantage.
Where there is No significant relative advantage, a “ Moderate ” weighting can be used.
Assumptions for SP2T Design:
Design is a Reflective SP2T.
(2) Diodes are used per RF port.
Frequency Bandwidth is 3.0 : 1 maximum.
Conclusions:
The Series-Shunt Design is the Best in terms of Overall Switch Performance and value. Since each Design has
a specific advantage, the decision for a Switch Design Selection is determined by the Specific Design Priorities
for the requirement.
2
ADVANCED:
Data Sheets contain information regarding a product M/A-COM Technology Solutions
•
North America
Tel: 800.366.2266 •
Europe
Tel: +353.21.244.6400
is considering for development. Performance is based on target specifications, simulated results,
•
India
Tel: +91.80.43537383
•
China
Tel: +86.21.2407.1588
and/or prototype measurements. Commitment to develop is not guaranteed.
Visit www.macomtech.com for additional data sheets and product information.
PRELIMINARY:
Data Sheets contain information regarding a product M/A-COM Technology
Solutions has under development. Performance is based on engineering tests. Specifications are
typical. Mechanical outline has been fixed. Engineering samples and/or test data may be available.
M/A-COM Technology Solutions Inc. and its affiliates reserve the right to make
Commitment to produce in volume is not guaranteed.
changes to the product(s) or information contained herein without notice.
AN3021
PIN Diodes for Microwave Switch Designs
Table 2: Relative PIN Diode Performance Evaluation Matrix
Surface Mount Assembly
Key Parameter
1 MHz < F < 1 GHz
100 MHz < F < 4 GHz
4 GHz < F < 20 GHz
20 GHz < F < 60 GHz
100 MHz < F < 20 GHz
Pinc < 0.1 W
0.1 W < Pinc < 1 W
1 W < Pinc < 20 W
20 W < Pinc < 200 W
Relative Cost Index
Lowest
Best Selection
Moderate/Highest Moderate/Highest
Best Selection
Best Selection
Best Selection
Lowest
Moderate
Highest
Best Selection
Best Selection
Best Selection
Best Selection
Best Selection
Best Selection
Best Selection
Rev. V2
Chip & Wire Hybrid Assembly
Cerma Chip
Flip Chip
Beam Lead
Plastic
MELF or Hi-
Pax
Best Selection
SURMOUNT
Conclusions:
1.
Plastic Devices
are best suited where
Cost
is a decision driver, the Operating Frequency < 4 GHz, and the
RF C.W. Incident Power < 1 W ( + 30 dBm ).
2.
MELF or HIPAX Ceramic Devices
are best utilized where
Highest Average Power
( > 20 W C.W. ) is the
Primary Design Goal and the Operating Frequency < 1 GHz.
3.
SURMOUNT Devices
are probably the
Best Overall Compromise
in Device Selection. They can Operate
( In Various bands ) from 10 MHz – 20 GHz and Perform well with RF Incident Power < 20 W C.W ( + 43
dBm ).
4.
Cermachip Devices
provide the
Best Overall Performance
for Operating Frequeny ( 100 MHz – 20
GHz ) , and RF Incident Power < 200 W C.W (+ 53 dBm ).
5.
Flip Chip Devices
are best suited for
mmwave Frequencies
< 60 GHz, where the RF Incident C.W. < 1W
( + 30 dBm ) and Conductive Epoxy or Soldering is Required.
6.
Beam Lead Devices
are best suited for
mmwave Frequencies
< 60 GHz, where the RF Incident C.W. <
0.1W ( + 20 dBm ) and Thermo Compression Bonding is Required.
3
ADVANCED:
Data Sheets contain information regarding a product M/A-COM Technology Solutions
•
North America
Tel: 800.366.2266 •
Europe
Tel: +353.21.244.6400
is considering for development. Performance is based on target specifications, simulated results,
•
India
Tel: +91.80.43537383
•
China
Tel: +86.21.2407.1588
and/or prototype measurements. Commitment to develop is not guaranteed.
Visit www.macomtech.com for additional data sheets and product information.
PRELIMINARY:
Data Sheets contain information regarding a product M/A-COM Technology
Solutions has under development. Performance is based on engineering tests. Specifications are
typical. Mechanical outline has been fixed. Engineering samples and/or test data may be available.
M/A-COM Technology Solutions Inc. and its affiliates reserve the right to make
Commitment to produce in volume is not guaranteed.
changes to the product(s) or information contained herein without notice.
AN3021
PIN Diodes for Microwave Switch Designs
Table 3: PIN Diode Part Number Series Matrix
Plastic PIN
Diodes
MELF & HiPax
PIN Diodes
SURMOUNT PIN
Diodes
Cermachip PIN
Diodes
Flip Chip PIN
Diodes
Beam Lead PIN
Diodes
Rev. V2
Part Numbers:
MA4P275 Series
MA4P282 Series
MA4P789 Series
MA4P274 Series
Part Numbers:
MA4P1250
MA4P1450
MA4P4000 Series
MA4P4300 Series
MA4P7000 Series
MA4P7100 Series
MA4PH23X Series
Part Numbers:
MA4SPS Series
MADP-042XXX
Series
Part Numbers:
MA4P102
MA4P202, 203
MA4P303
MA4P404
MA4P504
MA4P505
MA4P604
MA4P606
MA4PK2000, 3000
Part Numbers:
MA4FPC Series
MA4AGFCP Series
MA4AGSBP Series
Part Numbers:
MA4PBL Series
MA4AGBLP Series
Notes:
The following M/A-COM PIN Diode Drivers Operating with +5 V & -5 V D.C. Power Supplies are Practical
with Many PIN Diode Switch Designs: DR65 Series, MADRMA0001 and MADRMA0002 Series.
M/A-COM Website Homepage Hyperlink Address: http://www.macom.com
4
ADVANCED:
Data Sheets contain information regarding a product M/A-COM Technology Solutions
•
North America
Tel: 800.366.2266 •
Europe
Tel: +353.21.244.6400
is considering for development. Performance is based on target specifications, simulated results,
•
India
Tel: +91.80.43537383
•
China
Tel: +86.21.2407.1588
and/or prototype measurements. Commitment to develop is not guaranteed.
Visit www.macomtech.com for additional data sheets and product information.
PRELIMINARY:
Data Sheets contain information regarding a product M/A-COM Technology
Solutions has under development. Performance is based on engineering tests. Specifications are
typical. Mechanical outline has been fixed. Engineering samples and/or test data may be available.
M/A-COM Technology Solutions Inc. and its affiliates reserve the right to make
Commitment to produce in volume is not guaranteed.
changes to the product(s) or information contained herein without notice.
AN3021
PIN Diodes for Microwave Switch Designs
Schematic 1:
SP2T Series Exclusive PIN Diode Switch, 40 dB Isolation with +5 V Supply
+5V
Rev. V2
1K
SN5406
Open Collector
+ 5V TTL Driver
J1
+5V
270
Ω
B2 Bias
J3
B3
Bias
RF Series
Diodes
1K
J2
+5V
Forward Bias Diode Voltage,
ΔVf
@ 10 mA ~ + 0.9 V
Reverse Bias Diode Voltage = - ( +5 V - +2.3 V ) = - 2.7 V
SN5406 Open
Collector
+ 5V TTL Driver
Schematic 1:
D.C. Bias to RF Truth Table
RF State
Low Loss J1-J2 & Isolation J1-J3
Low Loss J1-J3 & Isolation J1-J2
B2 Bias
+0.5 V @ 10 mA
+5 V @ 0 mA
B3 Bias
+5 V @ 0 mA
+0.5 V @ 10 mA
5
ADVANCED:
Data Sheets contain information regarding a product M/A-COM Technology Solutions
•
North America
Tel: 800.366.2266 •
Europe
Tel: +353.21.244.6400
is considering for development. Performance is based on target specifications, simulated results,
•
India
Tel: +91.80.43537383
•
China
Tel: +86.21.2407.1588
and/or prototype measurements. Commitment to develop is not guaranteed.
Visit www.macomtech.com for additional data sheets and product information.
PRELIMINARY:
Data Sheets contain information regarding a product M/A-COM Technology
Solutions has under development. Performance is based on engineering tests. Specifications are
typical. Mechanical outline has been fixed. Engineering samples and/or test data may be available.
M/A-COM Technology Solutions Inc. and its affiliates reserve the right to make
Commitment to produce in volume is not guaranteed.
changes to the product(s) or information contained herein without notice.
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