One of the diodes is connected in series with the sensor while the other is shunt across it and the series diode. A pin diode is a current controlled device in contrast to a varactor diode which is a voltage controlled device. Microsemis pin diode rf switches are optimized for uhf high power and tr switching applications in which an sp2t switch is necessary. The two quarter wave sections operate in identical fashion in tx mode. Connecting the switch driver control circuit to a pin diode such that it can turn diodes on and off by applying a forward or reverse bias is a challenging task.
The switch makes use of a novel pin diode driver circuit that achieves high switching speeds while. We have extensive experience in switch design and development for critical space, telemetry, transceiver, radar, and ew applications. A highpower fourport transmitreceive switch was developed for an airborne vhf sar application. This page is designed to help a systems designer specify realizable pin diode switches.
References 1,2 provide a fuller treatment of this subject and can be used as a basis for rf switch switch driver interface designs. Based on both the experimental and the data sheet information, a diode selection is made and a switch circuit is realized using two pin diodes chapter 4. There are many unique market applications, such as the wireless communications market, where new. For example, the capacitance of an offstate discrete pin diode might be 1 pf. The diode in which the intrinsic layer of high resistivity is sandwiched between the p and nregion of semiconductor material such type of diode is known as the pin diode. Electronic tr switching and the ameritron qsk5 circuit. How to build a laser diode circuit hacked by 4lf45t.
Driving circuit for pin diode switches north american. Dsucser ultracompact series ultracompact pin diode drivers 52 kb rev 112098. Once the high voltage switch is turned on, current flows from the 600v supply, through the transistor, and then through the 10k ohm resistor to the cathode side of the pin diode switch. Rf pin diode sp4t switches are passive devices that route a high frequency signal through a set transmission path. Pin diode switch circuit for short time high current pulse signal. Dsdsser ds series decoded slow 50 nsec pin diode drivers 27 kb rev 111998. The steady state current, idc, is set by rp and is given by.
Cmos switch drivers macoms cmos switch drivers are used extensively in wireless infrastructure base stations as well as aerospace and defense applications. The pin diodes in the switch presented either a short circuit or an open circuit, depending on the bias condition. The increase in speed over the former driver system is a factor of 5. The switch driver provides output current surges or spikes on the leading and the trailing edge of the input voltage. The pin diode driver is based on readily available discrete components and achieves switching times for the reverse and forward bias states transmit on and off of 2. The information in this chapter is presented as a guide for the rf switch switch driver interface. In this chapter theory surrounding pin diode switches and their use in rf and microwave applications will be presented. It is capable of delivering peak currents in excess of one ampere at speeds up to 10 mhz. The driver utilizes fast switching npn transistors and skyworks discrete pin diodes.
The pin diode switch driver is located on the circuit board where the high voltage lead connects to the circuit board at point e. Pin diode drivers spectrum microwave offers a complete lineup of pin diode switch drivers with output current capability of 10 ma to 50 ma and switching speeds as fast as 6 ns. Api technologies offers a complete lineup of pin diode switch drivers with output current capability of 10 ma to 50 ma and switching speeds as fast as 6 ns. We can, on special request, provide single pole ninethrow pin diode switch sp9t, single pole tenthrow pin diode switch sp10t, single pole eleventhrow pin diode switch sp11t, singlepole twelvethrow pin diode switch sp12t and can array switches to form switch matrices to handle signal routing in complex systems. The driver circuit of claim 7, wherein one or more of the receive pin diode biasing circuit, the transmit pin diode biasing circuit, and the shunt pin diode biasing circuit comprises. This application note describes the use of pin diodes in circuit design. A driver circuit is a circuit which can limit appropriately the amount of current being fed into the laser diode, so that it can function correctly. Electronic tr switching and the ameritron qsk5 pin. Application notes how to specify pin diode switches.
The symbolic representation of the pin diode is shown in the figure below. I previously published a video that introduced the. Impellimax pin diode drivers, linearizer hybrids, gaas. Here we will compare driver circuits for pin diodes with those needed for switch fets. Figure 5 shows a singlepole doublethrow spdt rf switch and its bias circuit. Because of the complexity of designing a highspeed current driver circuit, the fet switch typically has an advantage in switching speed as well. Part number is um4010,manufactured by microsemi corp.
Figure 5 shows a singlepole doublethrow spdt rf switch. The driver circuit that is needed for pin diodes almost precludes the use of this technology on volumelimited applications such as tr modules, where element spacing is less than the width of available diode driver circuits. Driver circuit for highpower pin diode switches introduction the skyworks highpower pin diode switch driver circuit is a ttldtl compatible, dc coupled, highspeed pin diode bias controller. Series introduction this application note is intended to provide practical guidance in the selection of pin diodes for switch control circuit functions. There are some great vendors out there that can supply you with many types of pin switch drivers commercial, military, but they will remain nameless until they pay for an ad on this page. Nov 08, 20 this is a basic tutorial on pin diodes, with some examples of how they are used in rf switch applications. Electronic tr switching and the ameritron qsk5 pin switch. It is a silicon semiconductor diode in which a highresistivity, intrinsic i region is sandwiched between a ptype and ntype region. We utilize low parasitic capacitance for fast switching, small size, and excellent reliability.
Macoms cmos switch drivers are used extensively in wireless infrastructure base stations. Impellimax pin diode drivers, linearizer hybrids, gaas mmic. The bias circuit typically uses a lowpass filter between the rf circuit and the switch driver. Chapter 2, the common pin diode switch configurations are presented, followed by sections comparing those features of pin diode switch designs for unique to high power microwave switches and high power lower frequency rfband switches. Pin diodes are available at mouser electronics from industry leading manufacturers. Too little current and the laser diode will not have sufficient power to turn on and operate.
Infineon pin diodes come with low loss and low distortion levels and are suitable for a wide range of mobile communications and rf applications. It is designed for spdt switches operating with a cw input a power up to 100 w. We present a pin diode driver which functions in both an mri scanner and nmr spectrometer. In a simple spst pin diode switch figure 1, the diode can be either series or shuntconnected. Macoms cmos switch drivers are used extensively in wireless infrastructure base stations as well as aerospace and defense applications.
I use them as drive controls in some of my homebrew cw transceivers at a low level after the tx mixer and before the driver. Thin film metalization on ceramic substrates ensures low parasitic capacitance for fast switching, small size, and excellent reliability. Secondly, a section focusing on pin diode theory will be presented. The current therefore flows through the base of the high voltage switch, turning it on. Thus a pin diode is a dccontrolled highfrequency resistor, and if no dc current is present, the diode is just like an open circuit. Design and performance of a high speed driver circuit for pin.
A simple untuned singlepole, single throw spst switch may be designed using either a single series or shunt connected pin diode as shown in figure 5. The driver circuit may further comprise an antenna contact coupled to a node between a receive pin diode and a transmit pin diode of the plural pin diodes, a receive contact coupled to a node between the receive pin diode and a shunt pin diode of the plural pin diodes, and a transmit contact coupled to the transmit pin diode, wherein the bias. A high speed circuit was fabricated and tested to drive each pin diode switch. Pin diode switch circuit for short time high current pulse. When purchasing pin diode switches, it is important that they are completely specified to assure system performance. This will be followed by a section concerning the pin diode driver. En33x273 this driver reference design is designed to operate with the skyworks series of highpower spdt pin diode switches. Us patent application for programmable biasing for pin diode. Switches, digital and analog attenuators, and limiters each have unique functions that require proper device selection. The driver circuit that is needed for pin diodes almost precludes the use of this technology on volumelimited applications such as tr modules, where element spacing is. The pin diode is a currentcontrolled resistor at radio and microwave frequencies.
Jul 26, 2008 the carrier lifetime of pin diode i use is 10microsecondstyp. Thin film metalization on ceramic substrates ensures low parasitic capacitance for. The high resistive layer of the intrinsic region provides the large electric field between the p and nregion. These spikes inject or remove carriers from the pindiode junctions. A diode alone is not a complete and useful switch as it is only the core switching element. Nov 18, 2016 the driver circuit may further comprise an antenna contact coupled to a node between a receive pin diode and a transmit pin diode of the plural pin diodes, a receive contact coupled to a node between the receive pin diode and a shunt pin diode of the plural pin diodes, and a transmit contact coupled to the transmit pin diode, wherein the bias. Figure 7shows the dh0035 driving a cathode grounded pin diode switch. This is a basic tutorial on pin diodes, with some examples of how they are used in rf switch applications. This transition is the slower of the two transitions in a switching application since the driver circuit is attempting to remove stored charge from the pin diode. This series of diodes can operate up to 6ghz with highvoltage handling capabilities and together with outstanding rf performance, they simplify designin because of their extreme low forward. Pindiode bias interface connecting the switch driver control circuit to a pin diode such that it can turn diodes on and off by applying a forward or reverse bias is a challenging task. Please view our large selection of pin diodes below. At 320 mhz, the capacitive reactance of 1 pf is 497 ohms.
The diode consists the pregion and nregion which is separated by the intrinsic semiconductor material. I have a friend who has used them in an agc circuit. I use 1n4007 piv rectifier diodes as pin diodes in a non critical application. Pin diode driver circuits are a pain to design and build. I have read some ap notes of pin diodes, and got to know that switching speed of my antenna switch is not only related to carrier lifetime of pin diodes,but also related to driver. The hf power coming from the tx will see 50 ohms towards the antenna, and 0r ohms towards the pin diode at both t points r is the resistance of the pin diode. How and why to use pin diodes for rf switching digikey. At a minimum, an rf switch based on pin diodes needs a dc blocking capacitor to prevent the dc bias current from reaching the rf output, and an rf choke to provide a path for the dc bias current to return while blocking the rf signal. Pin diode drive circuits optimized for fast switching. The goal is to maintain connection of the sensor into the series test circuit except for a short period when a trigger pulse is initiated.
A pin diode switch suitable for switching radiofrequency voltages has a series circuit of two oppositely polarized pin diodes, with a control current supplied to the junction between the two pin diodes through the collectoremitter path of a transistor and through an inductor. Dsdfser df series decoded fast pin diode drivers 27 kb rev 111998. The anode and cathode are the two terminal of the pin diode. The driver utilizes four 2n6740 high voltage power transistors to turn the pin diode switches off and on. A microwave pin diode is a semiconductor device that operates as a variable resistor at rf and microwave frequencies. Drivers are typically used to translate ttl control voltages for rf and microwave attenuators and switches. What is the frequency range of the pin diode as an rf switch. Reverse voltage protection 30 mhz repetition ttl control protection test port short circuit protection operating characteristics. The anode is the positive terminal and cathode represent their negative terminals. L3 nardamiteq designs and manufactures a broad line of digital pin diode switches covering multioctave bands from 80 mhz to 44 ghz. Transistor driver circuit question no, the pin diode direction is correct.
Driver circuits for high power pin diode switches the information in this chapter is presented as a guide for the rf switch switch driver interface. Pin diode sp4t switches from pasternack are most commonly used in rf, microwave and millimeter wave test systems for routing varying signals between instruments, allowing multiple tests to be performed at the same time using the same setup. Pin diode drivers introduction the dh0035dh0035c is a ttldtl compatible, dc coupled, high speed pin diode driver. The electric field induces because of the movement of the holes and the electrons. The amplitude of these current spikes is typical 100ma with total switching times of less than 10 ns. The back bias voltage can be selected to be any voltage between 20 v to 50 v.
When the mosfet has a low in the gate it is off so the 10k works a as a pullup and turns the transistor on to apply reverse bias to the diode under test. Jun 19, 2019 thus a pin diode is a dccontrolled highfrequency resistor, and if no dc current is present, the diode is just like an open circuit. This driver is designed to provide forward currents up to 100 ma for each diode, and 28 v reverse bias. The necessity of using a highvoltage power pack to generate a high reverse bias in order to avoid limiting the. The proposed two pin diode switch circuit and driver is experimentally tested for compliance with the desired behavior. The carrier lifetime of pin diode i use is 10microsecondstyp. At a minimum, an rf switch based on pin diodes needs a dc blocking capacitor to prevent the dc bias current from reaching the rf output, and an rf choke to provide a path for the dc bias current to. The madr009150 switch driver is designed to work with macoms high power and high voltage pin diode switches. This article demonstrates how the dh0035 may be applied to driving pin diodes and comparable loads which. It is also important that the specifications be achievable. This driver has complementary outputs which can provide up to 200 ma bias current to a spdt pin diode switch. Design and performance of a high speed driver circuit for. Integrated biasing for pin diode drivers macom technology.
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