j } : Mien semi Corp. The diode experts SANTA ANA, CA / SCOTTSDALE, AZ / (602) 941-6300 DESCRIPTION This series of Microsemi 400mW Ultra-Stable Reference Diodes offers a CERTIFIED REFERENCE VOLTAGE STABILITY as measured over an actual operating period of 1000 hours. Standard stabilities are 10, 20, and 50 PPM/1000 hours. Units having stabilities of less than 5 PPM/1000 hours are available on special request. Ultra-Stable Certified Reference Diodes, available in standard or radiation 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. Wherever accurate and reliable measurements are to be made, the Microsemi Ultra-Stable diode excels as the Standard Reference device. 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 V and in PPM (Parts-Per-Million). Tocertify these diodes to such tight stabilities as 10 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 IN, i.e. RH4895A instead of IN4895A. Consult factory for TX, TXV or JANS equivalent SCDs. For more information call: 1N4890 thru 1N4895 and 1N4890A thru 1N4895A WITH CERTIFIED ZENER VOLTAGE STABILITY 6.35 VOLT ULTRA STABLE TEMPERATURE COMPENSATED ZENER: REFERENCE DIODES @) G.107 max. 2718 DIA. | 1| asauo ad potaairy 3.300 many. MARK LO 7620 {eATHODE) TO 4,900 as a0 MN. 0.010.022. aL a.as7i0.559 All dimensions in Men FIGURE 1 MECHANICAL CHARACTERISTICS CASE: Hermetically sealed glass case. DO-7 (DO-204AA). FENISH: All external surfaces are corrosion resistant and leads solderable. THERMAL RESISTANCE: 300C/W (Typical) function to'lead at 0.375- inches from body. POLARITY: Diode to be operated wath the banded end positive with to, the opposite end. WE HT: 0.2 grams. MOUNTING POSITION: Any 145146 6.35 VOLT ULTRA-STABLE (T.C.) ZENER REFERENCE DIODES MAXIMUM RATINGS (See Fig. 8) Operating Temperature Range: 65C to + 175C Maximum Lead Temperature 1/16 + 1/32 inch from case for 10 seconds: 230C Maximum DC Power Dissipation at or below 50C Ambient: 400 mW Linear Derating: 3.2 mW/C (See Figure 5) Maximum Steady State Current (I,,,) at 150C: 75 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 JEDEC VOLTAGE STABILITY EFFECTIVE TYPE NOMINAL ZENER MAXIMUM | TEMPERATURE 80C VOLTAGE NUMBER ZENER TEST ZENER STABILITY EFFECTIVE INITIAL-TO PEAK TIME VOLTAGE CURRENT IMPEDANCE L Ver TEMPERATURE AVar STABILITY +5% 0.01 mA 1n @ bir MAXIMUM TEMPERATURE | COEFFICIENT MAXIMUM (NITIAL-T0- Vz @ lar ha (NOTE 1) {NOTE 2) RANGE Qy2 {NOTE 3) PEAK VOLTS mA OHMS mv c %/C 7/1000 HRS. | PPM/1000 HRS. 1N4890 6.35 75 10 5.0 25 to 100 0.001 318 50 IN4890A, 6.35 75 10 10.0 56 to 100 4.001 318 50 1N4891 6.35 75 10 2.5 25 to 100 0.0005 318 50 1N4891A 6.35 75 10 5.0 55 to 100 0.0005 318 50 1N4892 6.35 75 10 5.0 25 to 100 0.001 127 20 1N4892A 6.35 75 16 10.0 55 to 100 0.001 127 20 1N4893 6.35 75 10 25 25 to 100 0.0005 127 20 1N4893A 6.35 75 10 5.0 55 to 100 0.0005 127 20 1N4894 6.35 75 10 5.0 25 to 100 0.001 64 10 1N4894A 6.35 75 10 10.0 55 to 100 0.001 64 10 1N4895 6.35 75 10 25 25 to 100 0.0005 64 10 IN4895A 6.35 75 10 5.0 55 to 100 0.0005 64 10 NOTE 1 NOTE 2 NOTE 3 The zener impedance is derived from Maximum allowable change ob- When operated at: the 60 Hz ac voltage which results when an ac current having an rms value equal to 10% of the DC zener current (1,,,) is superimposed on I,7. served over the entire temperature range i.e., the diode voltage will not exceed the specified mV change at any discrete temperature between Izy = 7.5 mA +0.0001 mA T, = 8C + 01C (See Note 2 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 norma! 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 opti- mum performance. Mounting the diode inside a large thermal mass such as aluminum, copper, brass, or epoxy will reduce thermally induced voltage fluctua- tions 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-6.35 VOLT ULTRA-STABLE (T.C.) ZENER REFERENCE DIODES ence voltage will shift due to diode impedance (A Vz= Alz x Zz). If the diodes junction temperature is allowed te 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 temperature coefficient of the diode. In addition, the device must be physically mounted so as to give the diode a constant thermal resistance, junction-to-ambient. Drafts, circulating oil, and even the minute convec- tion currents produced by a diode in a closed con- tainer can cause shifts in reference voltage greater than those that can be attributed to the diodes inherent stability. It must be understood that the certified stability is possible only under steady-state, constant tempera- ture conditions. The stability of an ultra-stable zener reference diode may be upset by severe changes in junction temperature. In addition, a slight derating of voltage-time stability (AVz7) may be experienced if the diode is operated outside the stable-area defined in Figure 5. The effect of turning the diodes current off and on at a constant temperature is neg- ligible (except for thermal warmup of diode). The certified stability of the diode is considered to be a worst case inherent junction stability, and will be realized only after 2 or 3 weeks of operation under actual operating conditions. This might be in the users circuit or finished product, however, the device must have this time to reach an equilibrium at operating conditions. The inherent stability of the device is never upset unless maximum ratings are surpassed. A new equilibrium must be reached with each new operating condition. Temperature coefficients much lower than specified can be attained by operating the diode at 0 TC crossover current (the point at which TC goes from positive to negative or vice-versa), however, a new equilibrium must be reached before full stability will be attained. 3. MICROSEMI! TEST METHOD: Micro- semi uses a potentiometric method of zener voltage measurement on certified reference diodes. Zener voltage is measured to seven digits (1 microvolt resolution). Voltage calibration is directly traceable to the National Bureau of Standards. Oil bath tem- perature is controlled to better than 0.1C, and current is constant and repeatable to better than +0.1 yA. Test clips are designed for the four-terminal method of measurement (separate voltage and cur- rent 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 SE- QUENCE: Voltage is measured seven times dur- ing the test with the last six measurements referenced to the first. The measurements are taken 168 hours apart, giving a total test time of 1008 hours. AVa PLOT OF A TYPICAL 1N4890 DIODE VOLTAGE DEVIATION IN PPM 0 168 336 504 672 FIGURE 2 OPERATING TEST TIME iN HOURS B40 1008 &Va PLOT OF A TYPICAL 1N4893 DIODE VOLTAGE DEVIATION 2.4 IN PPM VOLTAGE DEVIATION IN PPM 168 500 DERATING CHART Pd, RATED POWER DISSIPATION (mW) 25 50 100 150 200 T,, Lead temperature (C) 3/8" from body FIGURE 5 336 504 672 FIGURE 3 ~ OPERATING TEST TIME IN HOURS 4 336 504 672 FIGURE 4 OPERATING TEST TIME IN HOURS B40 1008 THE STABLE AREA" IS DEFINED AS THE AREA IN WHICH THE MAXIMUM TIME STABILITY (AV) IS ATTAINABLE. A SLIGHT DERATING IN THE TIME STABILITY MAY BE EXPECTED IF THE DIODE IS OPERATED OUTSIDE THIS AREA. 1476.35 VOLT ULTRA-STABLE (T.C.) ZENER REFERENCE DIODES 1000 HOUR STABILITY TEST SEQUENCE REF. Vz, vz, Vz, Vz3 Vz, Vz, Vz, Vz; i > f\~ ef i af i+ io a_i > oY ad > o o 1 t \ \ ; 1 I 1 { i t ' i ' | \ ! \ t \ { I 1 1 ! | i I I t : \ i ' ' \ \ ' ' t ! { ' I | ! I ! \ I \ i J \ I 1 t ' } ' \ \ | ' | | \ 1 ! ! | i I | 1g 336 HR. gig 168 HR. 168 HR. 168 HR. 168 HR. 168 HR. 1) 168 HR. >! Typ, PM 8 UR. " 8 HR. me +8 HR. +8 HR. He +8 HR ae =8 HR. ' ! ' t I | ' 1008 HRS. ($_______. +48 HR, ____________ > 8 HR. i Notes: Test Temperature .........- soC =0.1C Test Current ............... 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,. 148