AnalogTestWord下载.docx

1、 Analog Test :Hardware needed :a. Voltage sourceb. Prevision reference resistorc. MOAd. Internal voltmetere. Relay for connections-busi-busIRxIRefGain = Vmoa / VsIRx = IRef ; where summing Node = 0 volt with high input impedance of op-ampVs/Rx = Vmoa/Rref = 0 voltVs/Rx = - Vmoa/RrefRx = - （Vs/Vmoa）R

2、refGain = -Rref/RxTo make a good measurement, G always need to be between 1 to 10. Closer to 1, the best and stable test will be.What Need To Do If Rmeasure RxactualQuestion :What can cause voltage drop on Rx is actual ?Answer : Rx is fix, where the only variable is current flow thru Rx, IRxExample

3、:If there is another path which is connect to Rx, IRx What can cause voltage drop on Rx bigger then expected ? Addition impedance from s-bus or the internal voltage source from ASRU card, where the Rx = Rx + ZIRef = Vmoa / Rref,However IRx Vs / Rx, butIRx = Vs / （Rx + Rs + Ri ）Solution on addition i

4、mpedance form S-bus, Zs : Place a DVM to sense the voltage drop on Zs by adding “a-bus” The input impedance of DVM is pretty high and no current will than flow thru. This will not reduce the current flow thur Rx.Solution on addition impedance from I-bus, Zi :Add b-bus to move the virtual ground clos

5、e to DUTAdd “en” option, to enhance a. Voltage measurement across RRef b. Actual measurement on Vs instead of assume during measurement calculationWhat happen if there is G-Bus Impedance :With G-Bus internal impedance, it may cause IRx Rx actualAddition l bus to the circuitry will help to reduce G-b

6、us impedance.Note : The MOA impedance is infinite, and no current will then flow thru L-bus path.There is 2 ways of writing the l-bus connection :a. connect g to “node#”; l to “node#”b. connect gl to “node#”Complete Example with all Option :Analog Option :a. reX reference resistor for MOA range : re

7、1 to re6 : re1 = 10 ohm ; 101re2 = 100 ohm ; 102 use to define a most accurate G for analog measurementc. arX specify range setting for ASRUs internal multimeter, MOA arX use to set correct expected output voltage user seldon change on this setting default : 100mV for analog measurementd. amX Vs, so

8、urce voltage range setting Range of 10V to +10V Default value, Vs = 100 mV With refer to spec, measure passive component by using source of 100 mVe. wb bandwidth of MOA use during hihg MOA gain is needed at high frequency test wb normally not use during re1 & re2 setting, or it will intent to send M

9、OA to saturation statusf. waitX delay statement it will wait to execute each time voltage source is changes range from 0 to 9.99999 sec normal case using msec g. icoX current compliance of source ico0 : 35mA ico1 : 150mA by default 35mAh. frX frequency of source, Vs Using during capacitor & inductor

10、 measurement, ac component measurement 3 ranges : 128, 1024 & 8192 if frX is used, the source will automatically change from DC to AC i. comp/nocomp for capacitor learning purpose comp : will request a learn statement to the capacitor, normally use on 200pF nocomp : indicate the capacitor will not p

11、erform learning section. Learn capacitor will always do during the 1st run of the testj. Ed For line noise rejection Use together with fr128 This statement will increase test time of about 17.5 msec to 20 mseck. EnEnhance optionThis result a multiple measurement on deviceWith “en”, Vs, Vmoa, Vref an

12、d Vi to MOA will measureIt will incur addition test timel. sasense bus to reduce impedance of s-bus to Rx measurementm. sbsense bus to move the virtual ground reference to avoid impact from impedance of I-bus to Rxn. slsense bus to reduce impact from g-bus impedance to Rx measurementCapacitor Testin

13、g Hint :Some test structure using as resistor, capacitor is using MOA concept with AC source instead of DC.There will be needed for capacitor to have a compensation statement due to some capacitor induce between tester and fixture will cause some mis-reading on the measurement.The compensation state

14、ment will be use on the capacitor which 100 pF （ Sometime to be safe, 470pF will execute under comp option ）Recommended Capacitor Measurement Option :Diode & Zener Diode Test Configuration : Zener will use the same configuration, where forward bias voltage measurement for diode and reverse bias volt

15、age for zener. Diode : 0.7 volt （ 700 mvolt ） : forward bias voltage Zener : 18 volt : reverse bias voltage LED : 2.5 volt :Hint to Test Diode &a. Diode : Set voltage compliance （ co ） value at ealst 1 volt greater than hihg test limit Use guarding to eliminate the effect og impedance in parallel wi

16、th diode under test Ensure MOA output does not exceed 15 Vdc or 14Vpkb. Zener : Set voltage compliance, co to 10 volt, and 8.99 volts for auxiliary source. ar option for zener will be within range of 0 to 18 volt Do not use guarding on zener testFET Test Configuration :The FET test, nfetr and pfetr,

17、 measure on the resistor （ Ron ） of N-channel and P-channel FETs resepctively.The s-bus （ source bus ） and I-bus （ detector bus ） are connected to the source and drain of the FET. The guard, G-bus is connected to the gate of the FET.N-channel FETs are tested with a positive sourceP-Channel FETs are tested with a negative sourceHint For FETs test :Below shown the recommended Reference Element （ re ） Range of Ron testfr option, AC source can be use to reduce the effect of parallel impedance