Stanford Research Systems SIM954 Operation And Service Manual
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Stanford Research Systems SIM954 Operation And Service Manual

300 mhz dual inverting driver amplifier
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Operation and Service Manual
300 MHz Dual Inverting Driver Amplifier
SIM954
Stanford Research Systems
Revision 1.01
February 4, 2010

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  • Page 1 Operation and Service Manual 300 MHz Dual Inverting Driver Amplifier SIM954 Stanford Research Systems Revision 1.01 February 4, 2010...
  • Page 2 Copyright c Stanford Research Systems, Inc., 2008 – 2010. All rights reserved. Stanford Research Systems, Inc. 1290–D Reamwood Avenue Sunnyvale, CA 94089 USA Phone: (408) 744-9040 Fax: (408) 744-9049 www.thinkSRS.com e-mail: info@thinkSRS.com Printed in U.S.A. Document number 9-01649-903 SIM954 300 MHz Dual Inverting Driver Amplifier...

  • Page 3: Table Of Contents

    Contents General Information Safety and Preparation for Use ....Notation ......Specifications .
  • Page 4 5.2 Parts Lists ......5 – 4 5.3 Schematic Diagrams ....5 – 7 SIM954 300 MHz Dual Inverting Driver Amplifier...

  • Page 5: General Information

    BNC connectors, the chassis, the SIM interface connector, and may cause injury or death. The SIM954 is a single-wide module designed to be used inside the SIM900 Mainframe. Do not turn on the power until the module is completely inserted into the mainframe and locked in place.

  • Page 6: Specifications

    Input O set Voltage 1 mV user trimmable Input Bias Current 10 A user trimmable Operating Temperature 40 C Power Supply Voltages 15 V, 15 V Supply Current Internally current limited Table 1: SIM954 Specifications SIM954 300 MHz Dual Inverting Driver Amplifier...

  • Page 7: Operation

    1 Operation Following is a short overview on general guidelines for the operation of the SIM954. In This Chapter 1.1 Quick Start ......1 – 2 Operation Inside the SIM900 Mainframe .

  • Page 8: Quick Start

    SIM900 mainframe should be limited to a max- imum of four. The modules should be separated by at least one slot from each other, and any other module next to a SIM954 should not have an increased power consumption itself.

  • Page 9: Operation Using An External Power Supply

    SIM954 . Many BNC style 50 loads, terminators and attenuators, power split- ters, mixers, etc., are at risk of being damaged by a SIM954 if no further precautions against overload are taken. 1.3 Operation Using an External Power Supply Unlike other SIM modules, the SIM954 has additional power supply filtering and protection against inverse polarity conditions and is...

  • Page 10: Sim Interface Connector

    The connector signals are specified in Table 1.1. There is no microcontroller inside the SIM954 and the module does not communicate over its serial port. However, the status service re- quest line (-STATUS) serves as an indicator for an overload condition which can be detected by the mainframe or the user.

  • Page 11: Direct Interfacing

    The SIM954 power is internally well filtered, but it is recommended to use another set of RF beads and ceramic filter capacitors directly on the DB–15 receptacle in noise sensitive environments.
  • Page 12 1 – 6 Operation SIM954 300 MHz Dual Inverting Driver Amplifier...

  • Page 13: General Properties

    2 General properties In this chapter general properties of the SIM954 are being discussed. In This Chapter 2.1 DC Characteristics ....2 – 2 2.1.1...

  • Page 14: Dc Characteristics

    2.1.1 DC Gain The DC gain of each SIM954 channel is 4 or (12 dB) into 50 . This gain is load dependent. Since the amplifier has an output resistance of 3.3 , the following formula describes the e ective gain for a given...
  • Page 15 Users who wish to re-calibrate the input o set voltage and the input o set current can use the procedure described in Chapter 4. De- pending on the temperature range the SIM954 is exposed to, this procedure may slightly improve the input o set voltage.

  • Page 16: Ac Characteristics

    SIM954 input short. To maintain the best possible pulse response at 300 MHz ( 0 67m 26”) the maximal cable...

  • Page 17: Ac Gain

    These gain variations depend on the internal compensation of the op-amps (which are production lot dependent) and the tolerances of the gain setting resistors in the SIM954 . Since the THS3091 op-amps used in this module are transimpedance types, the gain peaking and the 3 dB point are controlled by the feedback resistor.
  • Page 18 All measurements are taken by suppressing the input mismatch with a 10dB attenuator directly at the SIM954 input. Frequency [MHz] Figure 2.3: Typical SIM954 gain plot SIM954 300 MHz Dual Inverting Driver Amplifier...
  • Page 19 2.2 AC Characteristics 2 – 7 Frequency [MHz] Figure 2.4: Typical SIM954 phase plot SIM954 300 MHz Dual Inverting Driver Amplifier...

  • Page 20: Noise

    Because of its relatively low gain and medium noise figure, the SIM954 does not qualify as a low noise amplifier, but it will still yield reasonable noise performance in applications which can toler- ate its modest 11 dB noise figure while requiring only small gains at large amplitudes, a domain which is usually poorly covered by other amplifiers.

  • Page 21: Crosstalk

    2 – 9 2.4 Crosstalk The two channels of a SIM954 module are not shielded from each other and exhibit crosstalk. Because of the geometric asymmetry of the module, the output of Channel 1 is closer to the input of Chan- nel 2 than vice versa.

  • Page 22: Isolation

    The following diagram shows the measured isolation between a SIM954 output and its input. The measurement was made with a network analyzer by connecting the source to the amplifier’s output and the network analyzer input to the amplifier’s input.
  • Page 23 Figure 2.6: SIM954 output to input isolation. The dashed line repre- sents power-o isolation, the solid line represents the powered state. The curves are interpolated between measured data (dots).

  • Page 24: Power Supply And Thermal Considerations

    General properties 2.6 Power Supply and Thermal Considerations A SIM954 module can initially draw up to 750 mA of power supply current from both 15 V rails of the SIM900 mainframe. It is therefore recommended that you limit the number of SIM954 modules to four per mainframe to stay within the 3 A power supply limits.

  • Page 25: Application Notes

    3 Application notes In this chapter properties and limits of the amplifier and its In This Chapter performance in typical applications are discussed. 3.1 Resistive Loads ..... . 3 – 2 Capacitive Load Handling .

  • Page 26: Resistive Loads

    This means that the SIM954 will develop its full output power in di erential and push-pull configurations. However, care has to be taken not to thermally overload the SIM954 in this mode. Finally, load resistances above 18 limit the output current...

  • Page 27: Capacitive Load Handling

    3.2 Capacitive Load Handling 3 – 3 SIM954 Output Voltage Limit Load Resistance [Ohm] Figure 3.1: SIM954 output voltage limit as a function of load resis- tance 3.2 Capacitive Load Handling Because the active part of each SIM954 amplifier channel is isolated from the load by a 3.3...

  • Page 28: Capacitive Reverse Currents

    This charge can cause a reverse current flow if the amplifier is turned o while it remains connected to a charged capacitor. Since the SIM954 does not guarantee by de- sign that this reverse current won’t harm the amplifier or the SIM900...

  • Page 29: Inductive Loads

    RL-highpass corner frequency. TDS 3034 24 Jul 2008 16:31:16 Figure 3.4: The SIM954 driving a 1 MHz square wave with 750 mA peak current into a 1 H inductor SIM954 300 MHz Dual Inverting Driver Amplifier...

  • Page 30: Dc Current And Inductor Saturation

    AC currents in the saturated core. Figures 3.5 and 3.6 show an example of inductor saturation. The SIM954 is driving an ultra-high permeability core with almost rect- angular magnetization curve, used in a fluxgate magnetometer, with a 10 kHz sine wave.

  • Page 31: Inductive Voltage Spikes

    . If the amplifier is being used as a coil driver, a suitable external voltage protection device (power zener diode, transient voltage sup- pressor, etc.) should be used. SIM954 300 MHz Dual Inverting Driver Amplifier...

  • Page 32: Transformers

    SIM954, and in many applications such a topology is advantageous. 3.4.1 Input Side Transformer An input transformer to the SIM954 can, but does not have to be isolated. Autotransformers and wideband transmission line trans- formers are equally well suited to drive the module.

  • Page 33: Output Side Transformer

    (i.e., in this case the SIM954 inputs), some of it will be transfered to this load resistor and will not be visible at the other output port (although some power will still make it to the input port because the circuit does not have perfect isolation between all ports).

  • Page 34: Load Impedance Matching Examples

    SIM954 as a small RF power amplifier. 3.5 Load Impedance Matching Examples The SIM954 is designed to generate up to 1 A output current into low impedances and up to 10 V output voltage into 50 . Because of its low output impedance of 3.3 , however, the amplifier cannot...

  • Page 35: Bridge Configuration

    3.6 Bridge Configuration By using both an input and an output transformer, two SIM954 chan- nels can be operated in a bridge configuration, thereby doubling the theoretical output power to 14 W and close to 10 W .

  • Page 36: Typical Application: A High Voltage Isolated, Low Noise, Dc-Dc Converter

    Application notes 3.7 Typical Application: a High Voltage Isolated, Low Noise, DC-DC Converter The ability of the SIM954 to drive significant power into a transformer can be used to provide isolated power to circuits under unusual circumstances for which no easy commercial solutions exists. In the following we describe a 5 V, 100 mA isolated DC-DC converter with 20 kV isolation.
  • Page 37 The transformer’s secondary winding is connected to a simple half- wave rectifier made from fast switching diodes such as the 1N4148. In order to achieve minimum switching noise, the SIM954 is used to drive the circuit with a sinusoidal voltage rather than a square wave (as in ordinary switching power supply circuits).
  • Page 38 50 V RMS noise on the order of less than 10 V is a realistic design goal. For improved common mode rejection, the transformer should be SIM954 300 MHz Dual Inverting Driver Amplifier...
  • Page 39 40 V per division. The peak-to-peak amplitude is 87 V and the ripple RMS is 17 V driven di erentially with two SIM954 channels by using an isolating 180 power splitter on their inputs to make a close to ideal sinusoidal di erential driver.

  • Page 40: Common Mode Emi Emf

    RF systems with a total signal gain of 60 dB or more. Since the SIM954 is an amplifier with very low output impedance, amplifier output side termination is poor by design. In addition, the signal gain and the high power of the amplifier increase the likelihood...
  • Page 41 filter properly. An example of a typical common mode scenario is shown in Fig- ure 3.11 where a SIM954 is driving a 4 V , 10 MHz square wave into an 8”...

  • Page 42: Overdrive Behavior

    Figures 3.13 and 3.14. TDS 3034 15 Jul 2008 16:01:02 TDS 3034 15 Jul 2008 16:01:53 Figure 3.13: The SIM954 driven with 1 kHz Figure 3.14: The SIM954 overdriven with triangle wave to 20 Vpp into 50...
  • Page 43 Preamplifier or the SIM964 Analog Limiter. The SIM914 will limit at approximately 2 V output signal level. When cascaded with a SIM954, it will result in approximately 8 V of clipping amplitude with 3 ns of input recovery from overload while providing 200 MHz of combined bandwidth while in linear mode.

  • Page 44: Miscellaneous Loads

    3.10.1 Heaters and Peltier Elements The SIM954 can be used to drive small (up to approximately 5 W) resistive heaters and Peltier elements in thermal control applications. If the amplifier specifications can potentially exceed the maximum heater or Peltier voltage or current, the user may add external pro- tection circuits to assure the safety of the attached load.

  • Page 45: Piezo Elements

    3.10.4 Piezo Elements The SIM954 output voltage limit of 10 V is too low to drive high voltage DC piezo elements. However, the module can drive piezo resonators very well. Because it has a limited output voltage, the piezo element has to be driven either by a series LC circuit, a trans- former, or a combination of both.
  • Page 46 3 – 22 Application notes SIM954 300 MHz Dual Inverting Driver Amplifier...

  • Page 47: Calibration

    SIM954 is a voltmeter with 0.1 mV resolution. 4.2 Offset Voltage and Input Bias Current Each of the two independent amplifiers of the SIM954 has one o set voltage and one input bias current trimmer. They can be accessed by removing the (right) side panel of the module which is on the side closest to the front panel LEDs.
  • Page 48 0 mV with R199. Iteration: Steps 3 and 4 are repeated as many times as necessary to trim both input and output o set voltage simultaneously to near 0 mV. SIM954 300 MHz Dual Inverting Driver Amplifier...
  • Page 49 5 Parts Lists and Schematics In This Chapter 5.1 Circuit Description ....5 – 2 Parts Lists ......5 – 4 Schematic Diagrams .
  • Page 50 5 – 2 Circuitry 5.1 Circuit Description The SIM954 contains two independent amplifiers and a power con- ditioning circuit. Each amplifier is primarily made out of four 250mA line driver op- amps (U101-U104 and U105-U109). The THS3091 95 family of line drivers are made by Texas Instruments using a robust 36 V RF bipolar process.
  • Page 51 Q307 and limits the gate voltage on the MOSFETs to approximately 750 mA. As the necessary base-emitter voltages to open Q305 and Q307 drop with higher temperature, these transistors automatically reduce the current at elevated module temperatures. SIM954 300 MHz Dual Inverting Driver Amplifier...
  • Page 52 5 – 4 Circuitry 5.2 Parts Lists The parts list is for reference only, and subject to change without notice. SIM954 300 MHz Dual Inverting Driver Amplifier...
  • Page 53 R205-R208 R218 R233 R237 R241 R255-R258 4-01117-110 1.00k R209-R212 4-01575-100 R213-R215 R263-R265 4-01551-100 1.0M R216 R266 4-01120-110 1.07K R217 R232 R236 R240 4-01222-110 12.4K R219 R234 R238 R242 4-00992-110 49.9 R220 R235 R239 R243 4-01128-110 1.30K SIM954 300 MHz Dual Inverting Driver Amplifier...
  • Page 54 R305 R311 4-00537-020 R306 R312 R328 4-01527-100 100K R320-R327 4-00935-110 12.7 U101-U108 U201 U203 3-01669-360 THS3091 5 U111 U112 3-01360-120 OPA228UA U202 U204-U206 3-00653-360 AD8561 U207 3-00662-103 74HC14 U303 3-00709-130 78L05 U304 3-00712-130 79L05 SIM954 300 MHz Dual Inverting Driver Amplifier...
  • Page 55 5.3 Schematic Diagrams 5 – 7 5.3 Schematic Diagrams Schematic diagrams follow this page. SIM954 300 MHz Dual Inverting Driver Amplifier...

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