Standby Current Test for JANTXV5649A Microsemi Transient Voltage Suppressor

/ Document # / Date effective
LAT-TD-05747-1 / 19 APRIL 04
Author(s) / Supersedes
Gunther Haller
Subsystem/Office
Electronics & DAQ Subsystem
Document Title
Standby Current Test for JANTXV5649A Microsemi Transient Voltage Suppressor

Hard copies of this document are for REFERENCE ONLY and should not be considered the latest revision.

LAT-TD-05747 Page 13

Change History Log

Revision / Effective Date / Description of Changes

1. SCOPE 4

2. Environmental condition 4

3. Caution 4

4. Notes 4

5. REFERENCES 5

5.1 Applicable Documents 5

6. TEST setup 6

6.1 Test Equipment 6

6.2 Test Setup 7

7. Appendix A (Data Sheets and Covers) 9

7.1 COVER SHEET 10

7.2 Test Overview and Important Measurement Comments 12

7.3 Current versus Voltage Curves 13

1. SCOPE

In this document the test-circuit and test-results are described for measuring the current as a function of voltage for MICROSEMI JANTXV5649A Transient Voltage Suppressor diodes.

2. Environmental condition

All measurements are performed at room-temperature in SLAC Building 33, clean-room.

3. Caution

1) In order to not take a chance damaging the transient suppressor device, the current must be limited by the measuring circuit if DC voltages over the break-down voltage are applied. The device is an AC voltage surge protector.

4. Notes

1) The stand-off voltage for the 1N5649A device is 40.2V. In GLAST LAT operation the nominal voltage applied to the diode is +28V +/- 1V. The device is used to suppress transient voltage spikes. The maximum voltage the diode needs to with-stand is 40V DC. The 40-V voltage limit is not tested at the instrument level but the effect needs to be investigated by analysis. (The 28V is generated via a DC/DC converter and is regulated.)

2) The maximum stand-off current according to the Microsemi data-sheet is 5 uA at 40.2V at room-temperature.

3) The voltage at which the junction breaks down is specified to be between 44.7V and 49.4V at 1 mA, well above the 40V maximum theoretical LAT voltage.

5. REFERENCES

The list below provides documents that are to be used as references for this procedure:

5.1 Applicable Documents

Document Number / Description
Microsemi 1N5629 thru 1N5665A Data-Sheet / Data-Sheet

6. TEST setup

6.1 Test Equipment

The list below indicates the equipment that is used in the test setup:

Type / Manufacturer/Model/ID Number
Power Supply PS A / Power Design TP1800 SLAC GLAST ID GLAT 1037
Resistor R1 / 1 kohm, 5%, 1/8 W
DVM A for V Measurement / Meterman 38XR SLAC GLAST ID GLAT 1069
DVM B for I measurement / Meterman 38XR SLAC GLAST ID GLAT 1075

6.2 Test Setup

Figure 1. Test setup. One set of measurements are performed with R1 included, the second with R1 removed after determination of the approximate break-down voltage

7. Appendix A (Data Sheets and Covers)

7.1 COVER SHEET

Program: GLAST

Procedure Number: LAT-TD-5747-1

Procedure Title: Standby Current Test for JANTXV5649A Microsemi Transient Voltage Suppressor

Unit Date-Code: D/C 0235B

REVIEWED AND APPROVED BY THE FOLLOWING:

Responsible Engineer: Gunther Haller EE Date: Feb 1, 05

Test Operator: Patrick Young EE Date: Feb 1. 05

Quality Assurance: YC Liew QA Date: Feb 1, 05

(Electronics Signatures)

7.2 Test Overview and Important Measurement Comments

In order to first confirm that the break-down voltage is not less than 44.7V in our test-setup, R1 in the test-setup is used to limit the current. (to be accurate we only determine the approximate break-down voltage, since the precious voltage is to me measured with a 1 mA current). After the approximate break-down voltage and the I versus V curve below the break-down voltage has been established, the resistor R1 is removed and the stand-by current at 40.2V is measured The latter measurement is only performed to eliminate any concerns that R1 would influence the stand-by current measurement (which is does not as expected).

Three diodes from lot D/C 0235B are tested.

The voltage applied to the diode is measured with DVM B and from the reading of the power-supply because of the voltage drop over R1.

A cross-check at a current of about 100uA thru the diode shows about a 100 mV drop over R1, as expected.

The current meter DVM A is connected after DVM B in order to not get a false measurement from the current flowing thru DVM B, the voltage meter.

It was confirmed that the voltage drop over the current meter DVM A is negligible (less than resolution of DVM B voltage reading).

The voltage applied to the diodes start at 40V or less and are incrementally increased to 47V.

First all measurements with R1 included in the circuit are performed for D1, then D2, then D3. After that R1 is removed and the stand-by current is confirmed for each diode at 40.2V.

These measurements are not meant to confirm the manufactures specification of the exact break-down voltage of at least 44.7V, since we do not inject a 1 mA constant current. (Although the break-down voltage is still approximate correct)

7.3 Current versus Voltage Curves

(for the first diode the V started at lower V to make sure the diode/circuit performs as expected. For the other diodes only voltage settings around the interesting regions are used.)

Voltage at TP1 / Current D1
With R1 / Current D2
With R1 / Current D3
With R1 / Current D1
Without R1 / Current D1
Without R1 / Current D3
Without R1
10V / 0.05 uA
30V / 0.05 uA
40V / 0.06 uA / 0.05 uA
40.2V / 0.06 uA / 0.06 uA / 0.05 uA / 0.04 uA
45V / 0.08 uA / 0.06 uA / 0.09 uA
46V / 0.13 uA / 0.14 uA
46.2V / 0.14 uA
46.3V / 0.21 uA
46.4V / 2.55 uA
46.5V / 42 uA / 0.08 uA / 0.22 uA
46.6V
46.7V / 0.09 uA
46.8V / 0.10 uA / 0.7 uA
46.9V / 0.44 uA / 73 uA
47V / 22 uA / 110 uA
47.05V / 117 uA

Result:

Diodes meet manufacturers specification in respect to stand-by currents being less than 5 uA at 40.2V with large margin (factor of about 100 at RT).

The device breaks down at between 46.3V and 47V, about in the middle of the manufactures specification of between 44.7V and 49.4V.

The diode meets the stand-by current specification quoted in the data-sheet.

Hard copies of this document are for REFERENCE ONLY and should not be considered the latest revision.

LAT-TD-05747 Page 13