background image

Model 2450 Interactive SourceMeter® Instrument User's Manual 

Section 7: Measuring I-V characteristics of FETs 

 

2450-900-01 Rev. C / December 2013 

7-13 

 

--Turn the stepper output on. 

node[2].smu.source.output = node[2].smu.ON 

readings = {} 

sourcevalues = {} 

iteration = 0 

steppoints = 4 

--Set the stepper V level, delay, start sweep, and wait to complete. 

for i = 2, 5 do 

   node[2].smu.source.level = i 

   delay(0.01) 

   trigger.model.initiate() 

   waitcomplete() 

   for j = 1, num do 

      readings[j+iteration*num] = defbuffer1[j] 

      sourcevalues[j+iteration*num] = defbuffer1.sourcevalues[j] 

   end 

   iteration = it1 

end 

--Turn the stepper output off. 

node[2].smu.source.output = node[2].smu.OFF 

--Print the formatted readings. 

if defbuffer1.n == 0 then 

   print("\nNo readings in buffer\n") 

else 

   for k = 1, num do 

      print(string.format("%f\t%f\t\t%f\t%f\t\t%f\t%f\t\t%f\t%f", sourcevalues[k], 

readings[k], sourcevalues[k+num], readings[k+num], sourcevalues[k+num*2], 

readings[k+num*2], sourcevalues[k+num*3], readings[k+num*3])) 

   end 

end 

 

The resulting drain current and drain voltage are returned in tabular form in the Instrument Console of 

Test Script Builder. You can copy the data into a spreadsheet, such as Microsoft

®

 Excel

®

, for 

graphing and further analysis.  
The following figure shows a graph of the family of curves generated in this example. 

 

Summary of Contents for Interactive SourceMeter 2450

Page 1: ...User s Manual 2450 900 01 Rev C December 2013 P245090001C 2450 900 01C www keithley com Model 2450 Interactive SourceMeter Instrument A Greater Measure of Confidence...

Page 2: ...art without the prior written approval of Keithley Instruments Inc is strictly prohibited TSP TSP Link and TSP Net are trademarks of Keithley Instruments Inc All Keithley Instruments product names are...

Page 3: ...be connected to mains These instruments will be marked as category II or higher Unless explicitly allowed in the specifications operating manual and instrument labels do not connect any instrument to...

Page 4: ...y disposed of according to federal state and local laws The WARNING heading in the user documentation explains dangers that might result in personal injury or death Always read the associated informat...

Page 5: ...mote communication interfaces 3 1 Supported remote interfaces 3 1 GPIB communications 3 1 Install the GPIB driver software 3 2 Install the GPIB cards in your computer 3 2 Connect GPIB cables to your i...

Page 6: ...7 Leakage current and insulation resistance 6 1 Introduction 6 1 Equipment required 6 1 Set up remote communications 6 2 Device connections 6 2 Measuring leakage current 6 4 Set up the leakage curren...

Page 7: ...plication using SCPI commands 8 7 Set up the battery application using TSP commands 8 8 Measuring I V characteristics of solar cells 9 1 Introduction 9 1 Equipment required 9 1 Set up remote communica...

Page 8: ...is manual provides detailed applications to help you achieve success with your Keithley Instruments Model 2450 In addition this manual provides the basics of the front panel to familiarize you with th...

Page 9: ...you can use as a starting point to create your own applications Reference Manual Includes advanced operation topics maintenance information troubleshooting procedures optimization strategies and in de...

Page 10: ...that show you how to perform tests from the front panel and using a remote interface These applications are presented after the summary information about the Model 2450 The applications include Making...

Page 11: ...the on position To turn it off press the power switch so that it is in the off position O HOME key Returns the display to the Home default screen MENU key Opens the main menu Press the icons on the m...

Page 12: ...ct a function touch the function on the touchscreen You can also turn the navigation control to highlight a function and then press the control to select the function TRIGGER key Accesses trigger rela...

Page 13: ...50 contains a separate protective earth safety ground wire for use with grounded outlets When proper connections are made the instrument chassis is connected to power line ground through the ground wi...

Page 14: ...powered on Turn off the equipment from the front panel or disconnect the main power cord from the rear of the Model 2450 before handling cables Putting the equipment into an output off state does not...

Page 15: ...t Use of clean room gloves to operate the touchscreen is supported Navigating the touchscreen To select an item on the displayed screen do one of the following Touch it with your finger Turn the navig...

Page 16: ...ustom text on the USER swipe screen use TSP or SCPI commands from a remote interface See the Model 2450 Reference Manual for details Figure 5 User defined text on the USER swipe screen TREND swipe scr...

Page 17: ...ons in each submenu open interactive screens For more detailed information about the menus see the Model 2450 Reference Manual Store measurements on a USB flash drive You can copy the measurement data...

Page 18: ...ront panel display to graphic file The instrument saves these graphic files also known as screen captures in sequentially numbered files to the USB flash drive To save the screen capture 1 Insert a US...

Page 19: ...communication interface LAN GPIB or USB when you connect to the respective port on the rear panel of the instrument In most cases you do not need to configure anything on the instrument In addition y...

Page 20: ...ore you connect the hardware This prevents associating the incorrect driver to the hardware Install the GPIB cards in your computer Refer to the documentation from the GPIB controller vendor for infor...

Page 21: ...controllers are usually set to 0 or 21 To be safe do not configure any instrument to have an address of 0 or 21 To change the controller address see the documentation for the controller The instrumen...

Page 22: ...g up the LAN see LAN troubleshooting suggestions on page 3 13 Set up LAN communications on the instrument This section describes how to set up manual or automatic LAN communications on the instrument...

Page 23: ...button next to Gateway and enter the gateway address 7 Select the button next to Subnet and enter the subnet mask 8 Select Apply Settings to save your settings Set up LAN communications on the comput...

Page 24: ...ruments 2 Select LXI Discovery Browser and then double click LXI Discovery Browser The Keithley LXI Discovery Browser window is displayed The Browser displays the instruments that it finds on the netw...

Page 25: ...nnect to Windows Update to search for software dialog box opens click No and then click Next 5 On the USB Test and Measurement device dialog box click Next and then click Finish Communicate with the i...

Page 26: ...ual 3 8 2450 900 01 Rev C December 2013 To use the Keithley Configuration Panel to determine the VISA resource string 1 Click Start All Programs Keithley Instruments Keithley Configuration Panel The S...

Page 27: ...ection 3 Using a remote interface 2450 900 01 Rev C December 2013 3 9 3 Click Next The Select Communication Bus dialog box is displayed Figure 11 Select Communication Bus dialog box 4 Select USB 5 Cli...

Page 28: ...00 01 Rev C December 2013 Figure 12 Select Instrument Driver dialog box 6 Select Auto detect Instrument Driver Model 7 Click Next The Configure USB Instrument dialog box is displayed with the detected...

Page 29: ...01 Rev C December 2013 3 11 Figure 13 Name Virtual Instrument dialog box 9 In the Virtual Instrument Name box enter a name that you want to use to refer to the instrument 10 Click Finish 11 Click Canc...

Page 30: ...ur system you can run Agilent Connection Expert to check your USB instruments See the Agilent documentation for information Using the web interface The Model 2450 web interface allows you to review ba...

Page 31: ...op is in a docking station Verify that the setup procedure used the configuration information for the correct ethernet card Verify that the network card of the computer is enabled Verify that the IP a...

Page 32: ...al front panel that you can use to control the instrument Links to the instrument web options including administrative options and LXI information Identify the instrument If you have a bank of instrum...

Page 33: ...specific language built on the SCPI standard TSP A programming language that you can use to send individual commands or use to combine commands into scripts SCPI 2400 An instrument specific language t...

Page 34: ...set from a remote interface Send the command LANG SCPI Reboot the instrument To change to the TSP command set from a remote interface Send the command LANG TSP Reboot the instrument To change to the...

Page 35: ...ou make measurements on a 10 k resistor by sourcing voltage and measuring current You can make similar measurements on any two terminal device under test DUT if appropriate source values are used Some...

Page 36: ...tions Connect the Model 2450 to the resistor in a 2 wire local sense configuration In this configuration the device is connected between the FORCE HI and FORCE LO terminals The physical connections to...

Page 37: ...CE VOLTAGE select the button next to Range 5 Select 20 V 6 Select the source voltage Under SOURCE VOLTAGE select the button next to Source 7 Enter 10 V and select OK 8 Set the limits for the source Un...

Page 38: ...in features of the Model 2450 optimize low resistance measurements such as remote sensing and offset compensation Equipment required One Model 2450 Interactive SourceMeter instrument For front panel c...

Page 39: ...om the instrument before powering the instrument Safe installation requires proper shields barriers and grounding to prevent contact with conductors There is no internal connection between protective...

Page 40: ...nnect the leads to the device under test DUT notice that the FORCE LO and SENSE LO connections are attached to one of the DUT leads Make the FORCE HI and SENSE HI connections to the other lead Connect...

Page 41: ...ng measurements Generate readings from the front panel or the remote interface Turn the source output off Set up the measurement from the front panel To set up the application from the front panel 1 M...

Page 42: ...screen swipe up on the TREND swipe screen to open the Graph screen View the buffer statistics on the front panel You can view the measurement statistics on the Model 2450 front panel including Buffer...

Page 43: ...meric data at the top of the screen and graphic data at the bottom of the screen You may need to make changes so that this code will run in your programming environment Send the following commands for...

Page 44: ...tance measurements by sourcing current and measuring resistance In this example the source current magnitude and limit voltage are set automatically It uses remote commands to change the front panel d...

Page 45: ...n you measure leakage current the results are returned in units of amperes When you measure insulation resistance the results are returned in units of ohms The leakage current application applies the...

Page 46: ...see Remote communication interfaces on page 3 1 Figure 23 Model 2450 remote interface connections Device connections Depending on the device under test DUT the current measurement is typically very sm...

Page 47: ...ation resistance tests The following figures show the rear terminal connections to the device under test DUT for these applications If capacitor leakage measurements are noisy you may need to use the...

Page 48: ...e period Turn on the source output Take readings for a specified period of time Turn off the source output When you use the Model 2450 to measure small current values ensure that the device under test...

Page 49: ...14 Press the HOME key to return to the Home screen 15 Press the TRIGGER key to turn on the output and make measurements The output is turned off when the measurements are complete View the measuremen...

Page 50: ...to autorange Set the number of power line cycles to 1 Load the Duration Loop trigger model to run for 60 s at 200 ms intervals Turn on the output Trigger the measurement Wait for the measurement to fi...

Page 51: ...cation Reset the instrument which also clears the buffer reset Set up the source function smu source func smu FUNC_DC_VOLTAGE smu source ilimit level 10e 3 smu source level 20 Set up measure function...

Page 52: ...d set You make insulation resistance measurements between traces on a printed circuit board and between conductors in cables and connectors This application sets the Model 2450 to source 20 V and make...

Page 53: ...he FUNCTION key 6 Under Source Voltage and Measure select Resistance 7 Select the button next to Source at the bottom of the screen 8 Enter 20 V or other applicable test voltage and select OK 9 Press...

Page 54: ...ent to measure resistance Use the Simple Loop trigger model to make 10 measurements at 100 ms Turn the output on Initiate readings Wait for the measurement to finish Read the resistance and time value...

Page 55: ...his example application Reset the instrument reset Set up the measure function smu measure func smu FUNC_DC_CURRENT smu measure unit smu UNIT_OHM smu measure terminals smu TERMINALS_REAR smu measure a...

Page 56: ...s and drain current The number of Model 2450 instruments required for testing depends on the number of FET terminals that must be biased and measured This application shows you how to perform a drain...

Page 57: ...ing figure shows the rear panel connection locations for the remote communication interfaces For additional information about how to set up remote communications see Remote communication interfaces on...

Page 58: ...ing the front panel For details see Set the GPIB address on page 3 3 If you are using USB cables to connect the computer and Model 2450 instruments each instrument must be connected to the computer wi...

Page 59: ...window opens 3 On the TSP Link tab next to Node enter the node number of this instrument 4 Select OK 5 Select Initialize 6 Press the HOME key to return to the home screen Repeat these steps for all M...

Page 60: ...ear panel female triaxial connectors to the MOSFET device Mount the MOSFET device in a metal shielded test fixture with female triaxial connectors Connect the Force LO terminals of both Model 2450 ins...

Page 61: ...VOLT RANG 20 SOUR CONF LIST CRE stepVals DIG LINE1 MODE TRIG OUT DIG LINE2 MODE TRIG IN TRIG DIG1 OUT STIM NOT1 TRIG DIG2 IN CLE TRIG DIG2 IN EDGE RIS Reset the instrument Set to measure current Set t...

Page 62: ...e for loop SMU 2 TRIG BLOC CONF RECALL 1 sweepVals TRIG BLOC SOUR STAT 2 ON TRIG BLOC WAIT 3 DIG1 TRIG BLOC DEL CONS 4 0 01 TRIG BLOC MEAS 5 TRIG BLOC CONF NEXT 6 sweepVals TRIG BLOC BRAN COUN 7 51 4...

Page 63: ...n the Description column describes a single line of code in the Commands column Send the following commands for this application SMU 1 SMU 2 or pseudocode Commands Description SMU 2 RST SENS FUNC CURR...

Page 64: ...n be returned from the arrays vds and ids Remote control of FET testing using TSP commands The two example sequences of Test Script Processor TSP commands for this application generate a drain family...

Page 65: ...s trigger EVENT_NOTIFY1 Populate the stepVals source config list with source levels 2 V to 5 V for i 2 5 do smu source level i smu source configlist store stepVals end Set up the trigger model trigger...

Page 66: ...igger model setblock 9 node 2 trigger BLOCK_BRANCH_COUNTER steppoints 3 node 2 trigger model setblock 10 node 2 trigger BLOCK_SOURCE_OUTPUT smu OFF Start the trigger model for both SMUs and wait until...

Page 67: ...mber of sweep points also used for printing num 51 Model 2450 1 drain setup Set up the source function smu source func smu FUNC_DC_VOLTAGE smu source ilimit level 300e 3 smu source autorange smu ON Se...

Page 68: ...j end iteration iteration 1 end Turn the stepper output off node 2 smu source output node 2 smu OFF Print the formatted readings if defbuffer1 n 0 then print nNo readings in buffer n else for k 1 num...

Page 69: ...7 Measuring I V characteristics of FETs Model 2450 Interactive SourceMeter Instrument User s Manual 7 14 2450 900 01 Rev C December 2013 Figure 34 MOSFET drain family of curves generated with two Mode...

Page 70: ...al Keithley office sales partner or distributor or call one of our Applications Engineers to get technical assistance Always follow the battery manufacturer s requirements for charging or discharging...

Page 71: ...is voltage difference drives a current that is immediately limited to the user defined current limit When in current limit the Model 2450 acts as a constant current source until it reaches the program...

Page 72: ...batteries capacitors and solar cells Configure instrument settings before making connections to the device Failure to consider the output off state source and limits may result in damage to the instru...

Page 73: ...g in any mode To prevent hazardous voltage from appearing on the LO terminals connect the LO terminal to protective earth if your application allows it You can connect the LO terminal to the chassis g...

Page 74: ...banana cables such as two sets of the Keithley Instruments Model 8608 High Performance Clip Lead Set Figure 37 Model 2450 front panel connections for the battery discharge and charge application The f...

Page 75: ...tage until the battery voltage reaches the desired voltage level and stop the test To charge the battery program the Model 2450 to output a voltage that is equivalent to the voltage rating of the batt...

Page 76: ...OUR VOLT 1 SOUR VOLT READ BACK ON SOUR VOLT RANG 2 SOUR VOLT ILIM 460e 3 SENS FUNC CURR SENS CURR RANG 1 OUTP ON Reset the instrument Turn on high impedance output mode Set to 4 wire sense mode Set to...

Page 77: ...our Model 2450 You can install and use TSB to write code and develop scripts for TSP enabled instruments Information about how to use TSB is in the online help for TSB and in the Introduction to TSP o...

Page 78: ...d voltage is equal to the voltage limit while true do Take a reading and get the current voltage and relative timestamp values curr smu measure read defbuffer1 volt defbuffer1 sourcevalues iteration t...

Page 79: ...8 10 2450 900 01 Rev C December 2013 The following figures show the results of this test application Figure 40 Model 2450 USER swipe screen showing test results 1 Measured load current 2 Measured batt...

Page 80: ...rent Imax and voltage Vmax Maximum power Pmax Open circuit voltage Voc Short circuit current Isc Because the Model 2450 has four quadrant source capability it can sink up to 1 A of cell current as a f...

Page 81: ...e measurement To use the 4 wire connection method Connect the FORCE LO and SENSE LO leads to the cathode terminal Connect the FORCE HI and SENSE HI leads to the anode terminal Make the connections as...

Page 82: ...s or rear panel terminals you cannot mix connections The rear panel connections are triaxial The front panel connections are safety banana jacks Turn the power to the instrument off before attaching c...

Page 83: ...l Reset the instrument Select the source voltage function and measure current function Set the current limit Select four wire remote sense mode Set up and generate a voltage sweep Initiate the trigger...

Page 84: ...the MENU key 8 Under Measure select Settings 9 Select the button next to Sense Mode and select 4 Wire Sense 10 Press the MENU key 11 Under Source select Sweep 12 Set the Start level to 0 V 13 Set the...

Page 85: ...ell current is measured The current and voltage measurements are stored in default buffer 1 defbuffer1 Send the following commands for this example application Command Description RST SENS FUNC CURR S...

Page 86: ...n the online help for TSB and in the Introduction to TSP operation section of the Model 2450 Reference Manual To use other programming environments you may need to make changes to the example TSP code...

Page 87: ...ilimit level 1 smu source sweeplinear SolarCell 0 0 53 num 0 1 Start the trigger model and wait for it to complete trigger model initiate waitcomplete Define initial values voltage defbuffer1 sourceva...

Page 88: ...nd the open circuit voltage VOC as shown in the figure below Figure 47 Solar cell I V sweep results on the USER swipe screen After the code is executed the measured current voltage and calculated powe...

Page 89: ...wers to the most common questions encountered with the Model 2450 For additional FAQs please see the Frequently Asked Questions FAQs section of the Model 2450 Reference Manual Where can I find updated...

Page 90: ...controlled remotely a message is displayed Select Yes to continue 11 When the upgrade is complete reboot the instrument A message is displayed while the upgrade is in progress Upgrade files are availa...

Page 91: ...boot the instrument To change to the TSP command set from a remote interface Send the command LANG TSP Reboot the instrument To change to the SCPI 2400 command set from a remote interface Send the com...

Page 92: ...oard to enter the name of the script 6 Select the OK button on the displayed keyboard The script is added to internal memory Using SCPI commands Configure the instrument to the settings that you want...

Page 93: ...u decrease the reading speed These settings take effect the next time the output is turned on and measurements are made The Quick Setups allow you to set the instrument to operate as a Voltmeter Ammet...

Page 94: ...so see the Keithley Instruments website www keithley com http www keithley com support for support and additional information about the instrument From the website you can access The Knowledge Center...

Page 95: ...perty of Keithley Instruments Inc All other trademarks and trade names are the property of their respective companies Keithley Instruments Inc Corporate Headquarters 28775 Aurora Road Cleveland Ohio 4...

Reviews: