/ Microsemi Corp. The diode experts SANTA ANA, CA SCOTTSDALE, AZ For more information call: (602) 941-6300 DESCRIPTION This series of Microsemi 250mW Ultra-Stable Reference Diodes offers a CERTIFIED REFERENCE VOLTAGE STABILITY as measured over an actual operating period of 1000 hours. Standard stabilities are 20, 50, and 100 PPM/1000 hours. Units having stabilities of less than 20 PPM/ 1000 hours are available on special request. Ultra-Stable Certified Reference Diodes, available in standard or radia- tion hardened construction, can be used in any circuit that requires a stable reference voltage that is insensitive to shock, vibration, or position. Their inherent stability allows them to be used in circuits requiring an extremely high degree of voltage time stability such as those in Digital Voltmeters, Computers, X-Y Recorders, Missile Guidance and Environmental Control Systems, and Portable Reference Standards. All devices in this series have been subjected to Microsemis 1000 hour Stability Test Sequence, consisting of a 1000 hour power age with reference voltage measured once every 168 hours giving a total of 7 individual test points. The stability test is performed at 80C +0.1C. A Certificate containing the following data is supplied with each diode: 1. The stability test voltage readings. 2. The voltage drift as referenced to Zero Hour in both wV and in PPM (Parts-Per-Million). To certify these diodes to such tight stabilities as 20 PPM/1000 hours, every factor of environment, both ambient and electrical is considered and controlled to Standards Laboratory accuracy. To specify radiation hardened devices, use RH prefix instead of 1N, i.e. RH3504 instead of 1N3504. Consult factory for TX, TXV or JANS equivalent SCDs. 1N3501 thru 1N3504 WITH CERTIFIED ZENER VOLTAGE STABILITY COMPENSATED ZENER. gh nge @6.35 VOLT ULTRA-STABLE (T.C.) ZENER REFERENCE DIODES MAXIMUM RATINGS (See Fig. 5) Operating Temperature Range: 65 to +150C Maximum Lead Temperature 1/8 +1/32 inch from case for 8 seconds: 230C Maximum DC Power Dissipation at or below 25C Ambient: 250 mW Linear Derating: 2.0 mW/C (See Figure 5) Maximum Steady State Current (Izu) at 125C: 7.5 mA MECHANICAL CHARACTERISTICS Case: Hermetically sealed glass Dimensions: DO-7 outline Finish: All external surfaces are corrosion re- sistant and leads are readily solderable Polarity: Diode to be operated with the banded end positive Weight: 0.2 grams (typical) Mounting Position: Any ELECTRICAL CHARACTERISTICS @ 25C unless otherwise specified VOLTAGE TIME VOLTAGE STABILITY EFFECTIVE ene NOMINAL | ZENER | MAXIMUM | TEMPERATURE @ 80C VOLTAGE ZENER TEST ZENER STABILITY INITIAL-TO PEAK TIME NUMBER | vortace | CURRENT | IMPEDANCE A Vax EFFECTIVE AVn STABILITY 5% | +0.01mA| Z@lz | MAXIMUM | TEMPERATURE | TEMPERATURE | MAXIMUM INITIAL-TO- V2 @ br tar (NOTE 1) | (NOTE 2) RANGE COEFFICIENT | (NOTE 3) PEAK vOLTs mA aHMS av c %fC a/1000 HRS. | PPM/ 1000 HRS. 1N3501 | 6.26.5 75 12 6 25 to 100 001 635 100 1N3502 | 6.2.65 75 12 3 25 to 100 0005 635 100 1N3503 | 6.265 75 12 8 25 to 100 001 318 50 1n3504 | 6.26.5 75 12 6 25 to 100 001 127 20 NOTE 1 NOTE 2 NOTE 3 The zener impedance is derived from the 60 Hz ac voltage which results when an ac current having an rms value equal to 10% of the DC zener current (I,,,) is superimposed on I,,7. The maximum allowable change ob- served over the entire temperature range i.e., the diode voltage will not exceed the specified mV change at any discrete temperature between When operated at: In7 = 7.5 mA +0.0001 mA Ty = 80C + 0.1C (See Precautions Below } the established limits. NOTES AND PRECAUTIONS FOR CERTIFIED REFERENCE DIODES 1. DIODE IDENTIFICATION: The diodes are shipped attached to their certification papers and each diode is individually packaged with the diode identification on the package. Identification includes JEDEC type number and a diode serial number con- sisting of 7 digits showing the lot number and diode number, which provide traceability to factory records. 2. PRECAUTIONS: The normal precautions must be taken when soldering as with any semicon- ductor device, such as a thermal shunt between the soldering iron and the diode body. Mechanical rather than solder mounting is preferred for optimum performance. Mounting the diode inside a large ther- mal mass such as aluminum, copper, brass, or epoxy will reduce thermally induced voltage fluctuations discernible as low frequency noise in the 0-3 Hz region of the spectrum. Certain precautions must be taken to ensure that the diodes stability is fully utilized in the circuit. If the current through the zener is not controlled, the refer- ence voltage will shift due to diode impedance (AV, = Al, x Zzrz). If the diodes junction temper- 132 ature is allowed to change, due to a change in ambient or case temperature or due to a power level change, a shift in voltage will occur consistent with the tem- perature coefficient of the diode. In addition, the de- vice must be physically mounted so as to give the diode a constant thermal] resistance, junction-to- ambient. Drafts, circulating oil, and even the minute convection currents produced by a diode in a closed container can cause shifts in reference voltage greater than those that can be attributed to the diodes inherent stability. The certified stability of a diode is achieved only under steady state, constant temperature conditions. If the diode is operated at conditions other than the certification test conditions, it is recommended that it be operated for a period of 2 to 3 weeks under circuit operating conditions to achieve rated stability. A slight derating of voltage-time stability (AV,,) may be experienced if the diode is operated outside the stable-area defined in Figure 5. Temperature coefficients much lower than specified can be attained by operating the diode at the O TC crossover current (the current at which the tempera-6.35 VOLT ULTRA-STABLE (T.C.) ZENER REFERENCE DIODES ture coefficient changes from positive to negative). 3. MICROSEMI TEST METHOD: Microsemi uses a potentiometric method of zener voltage measurement on certified reference diodes. The measurement facility is calibrated utilizing Pri- mary Voltage Standards directly traceable to the National Bureau of Standards. Room ambient tem- perature is controlled to +0.5C. Zener voltage is measured to seven digits (1 microvolt resolution). better than 0.1 uA. Test clips are designed for the four-terminal method of measurement (separate volt- age and current connections) to eliminate errors caused by resistance. The diodes are thermally shielded by an aluminum thermal filter to reduce thermally created error-causing voltage fluctuations, 4.1000 HOUR STABILITY TEST SEQUENCE: Voltage is measured seven times during the test with the last six measurements refer- Oil bath temperature is controlled to better than 0.1C, and current is constant and repeatable to enced to the first. The measurements are taken 168 hours apart, giving a total test time of 1008 hours. AV, PLOT OF A TYPICAL 1N3501 DIODE VOLTAGE +40 +40 DEVIATION IN PPM 0 168 336 504 672 840 1008 FIGURE 2~ OPERATING TEST TIME IN HOURS AV, PLOT OF A TYPICAL 1N3503 DIODE VOLTAGE +15.0 23.0 +23.3 DEVIATION IN PPM oO 168 336 504 672 840 1008 FIGURE 3 OPERATING TEST TIME IN HOURS AV, PLOT OF A TYPICAL 1N3504 DIODE VOLTAGE DEVIATION . 2.4 IN PPM 168 336 504 672 840 1008 FIGURE 4OPERATING TEST TIME IN HOURS DERATING CHART 500 THE STABLE AREA IS DEFINED AS ge 400 THE AREA IN WHICH THE MAXIMUM > 300 TIME STABILITY (AV) |S ATTAINABLE. ae 200 A SLIGHT DERATING IN THE TIME eo STABILITY MAY BE EXPECTED IF THE 2 100 DIODE 1S OPERATED OUTSIDE THIS oF: : a AREA, 25 50 100 150 200 FIGURE 5 TL, Lead temperature (C) 3/8 trom body 1336.35 VOLT ULTRA-STABLE (T.C.) ZENER REFERENCE DIODES 1000 HOUR STABILITY TEST SEQUENCE REF. Vz, Vz, Vz, Vz; Vz, Vz, Vz, Vz, i> iy fy iy i> ; r 0 O Y v oy oT OT ! ! | ! ! ! | | I ' I ! ! | i ' ! \ ! | \ \ \ ' ' ) \ \ \ ! 1 1 | ! | ! 1 ! I ! | | | | \ { \ | | { ' 1 ' I | 1 \ ! I ' \ | | { ' 1 | ! 1 ! 1 ( 1 336 HR. if 168 HR. 168 HR. 168 HR. 168 HR. 168 HR. 4, 168 HR. tye, PI 8 HR. mete HR. me 8 HR. +8 HRY 8 HR. PM 8 HR. ' | I ! I ! 1008 HRS. {$< +48 HR. ______________ 8 HR. I Notes: Test Temperature .......... so Cc +0.1C Test Current ............4.. 7.5 mA. with a constancy and repeatability of +0.1 microamp. The first 336 hours of operation is a stabilization period. The stability of a diode is measured by the worst voltage difference (AVz) referenced to Vz. 134