The documentation and process conversion measures necessary to comply with this revision shall be completed by 28 March 2002. INCH-POUND MIL-PRF-19500/426D 28 December 2001 SUPERSEDING MIL-PRF-19500/426C 2 November 2000 PERFORMANCE SPECIFICATION SEMICONDUCTOR DEVICE, TRANSISTOR, PNP, SILICON, AMPLIFIER TYPE 2N4957 AND 2N4957UB JAN, JANTX, JANTXV, AND JANS This specification is approved for use by all Departments and Agencies of the Department of Defense. 1. SCOPE 1.1 Scope. This specification covers the performance requirements for PNP silicon, VHF-UHF amplifier transistors. Four levels of product assurance are provided for each device type as specified in MIL-PRF-19500. 1.2 Physical dimensions. See figure 1 (T0-72) and figure 2 (surface mount). 1.3 Maximum ratings. PT (1) TA = +25°C mW VCEO V dc VCBO V dc IC VEBO mA dc V dc °C 3.0 -65 to +200 200 30 30 30 (1) Derate at 1.14 mW/°C above TA > +25°C. TSTG and TJ * 1.4 Primary electrical characteristics (common to all types). Limits Min Max hFE3 |hfe| rb'Cc rb'Cc Ccb VCE = 10 V dc IC = 5.0 mA dc IE = 2.0 mA dc VCE = 10 V dc f = 100 MHz IE = 2.0 mA dc f = 63.6 MHz VCB = 10 V dc (2N4957 only) IE = 2.0 mA dc f = 63.6 MHz VCB = 10 V dc (2N4957UB only) VCB = 10 V dc IE = 0 100 kHz ≤ f ≤ 1 MHz ps ps pF dB dB 1.0 8.0 1.0 16.0 0.8 17 25 3.5 30 165 12 36 Gpe IC = 2.0 mA dc f = 450 MHz VCE = 10 V dc NF IC = 2.0 mA dc VCE = 10 V dc f = 450 MHz Beneficial comments (recommendations, additions, deletions) and any pertinent data which may be of use in improving this document should be addressed to: Defense Supply Center Columbus, ATTN: DSCC-VAC, P. O. Box 3990 East Broad Street, Columbus, OH 43216-5000, by using the Standardization Document Improvement Proposal (DD Form 1426) appearing at the end of this document or by letter. AMSC N/A DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. FSC 5961 MIL-PRF-19500/426D * FIGURE 1. Physical dimensions of transistor type 2N4957. 2 MIL-PRF-19500/426D Symbol Dimensions Inches Notes Millimeters Min Max Min Max CD 0.178 0.195 4.52 4.95 CH 0.170 0.210 4.32 5.33 HD 0.209 0.230 5.31 5.84 LC .100 TP 5 5 2.54 TP LD 0.016 0.021 0.406 0.533 7,8 LL 0.500 0.750 12.70 19.05 7,8 LU 0.016 0.019 0.41 0.48 7,8 1 .27 8 L1 0.050 L2 0.250 6.35 P 0.100 2.54 8 Q 0.050 1.27 r .007 0.18 TL 0.028 0.048 0.71 1.22 TW 0.036 0.046 0.91 1.17 α 45° T. P. 5 45° T. P. NOTES: 1. Dimension are in inches. 2. Metric equivalents are given for general information only. 3. Beyond r (radius) maximum, TH shall be held for a minimum length of .011 (0.28 mm). 4. Dimension TL measured from maximum HD. 5. Body contour optional within zone defined by HD, CD, and Q. 6. Leads at gauge plane .054 +.001 -.000 inch (1.37 +0.03 -0.00 mm) below seating plane shall be within .007 inch (0.18 mm) radius of true position (TP) at maximum material condition (MMC) relative to tab at MMC. The device may be measured by direct methods. 7. Dimension LU applies between L1 and L2. Dimension LD applies between L2 and LL minimum. Diameter is uncontrolled in L1 and beyond LL minimum. 8. All four leads. 9. Dimension r (radius) applies to both inside corners of tab. 10. In accordance with ANSI Y14.5M, diameters are equivalent to φx symbology. 11. Lead 1 = emitter, lead 2 = base, lead 3 = collector, lead 4 = case (electrically connected). * FIGURE 1. Physical dimensions of transistor type 2N4957 Continued. 3 MIL-PRF-19500/426D Dimensions Symbol A A1 B1 B2 B3 D D1 D2 D3 E E3 L1 L2 Inches Min .046 .017 .016 .016 .016 .085 .071 .035 .085 .115 .022 .022 Millimeters Min Max 0.97 1.42 0.43 0.89 0.41 0.61 0.41 0.61 0.41 0.61 2.41 2.74 1.81 2.01 0.89 0.99 2.41 2.74 2.82 3.25 3.25 0.56 0.96 0.56 0.96 Max .056 .035 .024 .024 .024 .108 .079 .039 .108 .128 .128 .038 .038 Note NOTES: 1. Dimensions are in inches. 2. Metric equivalents are given for general information only. FIGURE 2. Physical dimensions, surface mount (2N4957UB version). 4 MIL-PRF-19500/426D 2. APPLICABLE DOCUMENTS 2.1 General. The documents listed in this section are specified in sections 3 and 4 of this specification. This section does not include documents cited in other sections of this specification or recommended for additional information or as examples. While every effort has been made to ensure the completeness of this list, document users are cautioned that they must meet all specified requirements documents cited in sections 3 and 4 of this specification, whether or not they are listed. 2.2 Government documents. 2.2.1 Specifications, standards, and handbooks. The following specifications, standards, and handbooks form a part of this document to the extent specified herein. Unless otherwise specified, the issues of these documents are those listed in the issue of the Department of Defense Index of Specifications and Standards (DoDISS) and supplement thereto, cited in the solicitation (see 6.2). SPECIFICATION DEPARTMENT OF DEFENSE MIL-PRF-19500 - Semiconductor Devices, General Specification for. STANDARD DEPARTMENT OF DEFENSE MIL-STD-750 - Test Methods for Semiconductor Devices. (Unless otherwise indicated, copies of the above specifications, standards, and handbooks are available from the Document Automation and Production Services (DAPS), Building 4D (DPM-DODSSP), 700 Robbins Avenue, Philadelphia, PA 19111-5094.) 2.2 Order of precedence. In the event of a conflict between the text of this document and the references cited herein, the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained. 3. REQUIREMENTS 3.1 General. The requirements for acquiring the product described herein shall consist of this document and MIL-PRF-19500. 3.2 Qualification. Devices furnished under this specification shall be products that are manufactured by a manufacturer authorized by the qualifying activity for listing on the applicable qualified manufacturer's list (QML) before contract award (see 4.2 and 6.3). 3.3 Abbreviations, symbols, and definitions. Abbreviations, symbols, and definitions used herein shall be as specified in MIL-PRF-19500. 3.4 Interface and physical dimensions. The interface and physical dimensions shall be as specified in MIL-PRF-19500, and figure 1 (T0-72 ) and 2 (UB, surface mount). 3.4.1 Lead finish. Unless otherwise specified, lead finish shall be solderable in accordance with MIL-STD-750, MIL-PRF-19500, and herein. Where a choice of lead finish is desired, it shall be specified in the acquisition document (see 6.2). * 3.5 Marking. Devices shall be marked in accordance with MIL-PRF-19500, except for the UB suffix package. Marking on the UB package shall consist of an abbreviated part number, the date code, and the manufacturer's symbol or logo. The prefixes JAN, JANTX, JANTXV, and JANS can be abbreviated as J, JX, JV, and JS respectively. The "2N" prefix and the "UB" suffix can also be omitted. 5 MIL-PRF-19500/426D 3.6 Electrical performance characteristics. Unless otherwise specified herein, the electrical performance characteristics are as specified in 1.3, 1.4, and table I. 3.7 Electrical test requirements. The electrical test requirements shall be the subgroups specified in table I, group A herein. 3.8 Workmanship. Semiconductor devices shall be processed in such a manner as to be uniform in quality and shall be free from other defects that will affect life, serviceability, or appearance. 4. VERIFICATION 4.1 Classification of inspections. The inspection requirements specified herein are classified as follows: a. Qualification inspection (see 4.2). b. Screening (see 4.3) c. Conformance inspection (see 4.4). 4.2 Qualification inspection. Qualification inspection shall be in accordance with MIL-PRF-19500 and as specified herein. * 4.3 Screening (JANTX, JANTXV and JANS levels only). Screening shall be in accordance with table IV of MIL-PRF-19500 and as specified herein. The following measurements shall be made in accordance with table I herein. Devices that exceed the limits of table I herein shall not be acceptable. Measurement Screen (see table IV of MIL-PRF-19500) JANS level JANTX and JANTXV levels 3c Thermal impedance, method 3131 of MIL-STD-750 Thermal impedance, method 3131 of MIL-STD-750 7 Hermetic seal (optional) (1) 9 ICBO1, hFE3 Not applicable 10 24 hours minimum 24 hours minimum 11 ICBO1; hFE3; ∆ICBO1 = 100 percent of initial value or10 nA dc, whichever is greater. ∆hFE3 = ±20 percent ICBO1 ,hFE3 12 See 4.3.1, 240 hours minimum See 4.3.1, 80 hours minimum 13 Subgroups 2 and 3 of table I herein; ∆ICBO1= 100 percent of initial value or 10 nA dc, whichever is greater; ∆hFE3 = ±20 percent Subgroup 2 of table I herein; ∆ICBO1= 100 percent of initial value or 10 nA dc, whichever is greater; ∆hFE3 = ±20 percent (1) Hermetic seal test shall be performed in either screen 7 or screen 14. 6 MIL-PRF-19500/426D 4.3.1 Power burn-in. Power burn-in conditions are as follows: TA = Room ambient as defined in the general requirements of 4.5 of MIL-STD-750, VCB = 10 - 20 V dc. A power dissipation PD = 100 percent of PT maximum as defined in 1.3 shall be used. 4.4 Conformance inspection. Conformance inspection shall be in accordance with MIL-PRF-19500, and as specified herein. If alternate screening is being performed in accordance with appendix E, "Alternate procedure for screening of JANTX and JANTXV types", of MIL-PRF-19500, a sample of screened devices shall be submitted to and pass the requirements of group A1 and A2 inspection only (table VIb, group B, subgroup 1 is not required to be performed again if group B has already been satisfied in accordance with 4.4.2). 4.4.1 Group A inspection. Group A inspection shall be conducted in accordance with MIL-PRF-19500, and table I herein. 4.4.2 Group B inspection. Group B inspection shall be conducted in accordance with the tests and conditions specified for subgroup testing in table VIa (JANS) of MIL-PRF-19500 and 4.4.2.1 herein. (See 4.4.2.2 for JAN, JANTX, and JANTXV group B testing.) Electrical measurements (end-points) and delta requirements shall be in accordance with table II herein as specified in the footnotes for table II. * 4.4.2.1 Group B inspection, table VIa (JANS) of MIL-PRF-19500. Subgroup Method Condition B4 1037 VCB = 10 V dc. B5 1027 VCB = 10 - 20 V dc minimum PD = maximum rated PT (see 1.3), TJ = +150°C minimum, t = 1000 hours minimum. 4.4.2.2 Group B inspection, (JAN, JANTX, and JANTXV). Separate samples may be used for each step. For rules on resubmission for failed steps, see MIL-PRF-19500 rules on resubmission of failed subgroups. Step Method Condition 1. 1039 Steady-state life: Test condition B, 340 hours, VCB = 10 - 20 V dc. n = 45 devices, c = 0. Maximum rated power as defined in 1.3 shall be applied to the device to achieve a TJ = 150°C minimum. 2. 1039 Steady-state life test of step 1 shall be extended to 1,000 hours for each die design. Samples shall be selected from a wafer lot every twelve months of wafer production. Group B step 2 shall not be required more than once for any single wafer lot. n = 45 devices, c = 0 3. 1032 High-temperature life (non-operating), TA = +200°C n = 22, c = 0 4.4.2.3 Group B sample selection. Samples selected from group B inspection shall meet all of the following requirements: a. For JAN, JANTX and JANTXV samples shall be selected randomly from a minimum of three wafers (or from each wafer in the lot) from each wafer lot. For JANS, samples shall be selected from each inspection lot. See MIL-PRF-19500. b. Must be chosen from an inspection lot that has been submitted to and passed group A, subgroup 2 conformance inspection. When the final lead finish is solder or any plating prone to oxidation at high temperature, the samples for life test (subgroups B4 and B5 for JANS, and group B for JAN, JANTX and JANTXV) may be pulled prior to the application of final lead finish. 7 MIL-PRF-19500/426D 4.4.3 Group C inspection, JANS. Group C inspection shall be conducted in accordance with the tests and conditions specified for subgroup testing in table VII of MIL-PRF-19500, and 4.4.3.1 herein (JANS). See 4.4.3.2 for JAN, JANTX, and JANTXV group C testing. Electrical measurements (end points) and delta requirements shall be in accordance with the steps of table II herein and as specified in the notes for table II. 4.4.3.1 Group C inspection, table VII (JANS) of MIL-PRF-19500. Subgroup Method Condition C2 2036 Test condition E; not applicable for UB devices. C6 1026 VCB = 10 - 20 V dc; PT = maximum rated power as defined in 1.3. Adjust TA to achieve TJ = +150°C minimum. 4.4.3.2 Group C inspection, JAN, JANTX, and JANTXV. Group C inspection (JAN, JANTX, and JANTXV), see table VII of MIL-PRF-19500. Subgroup C2 C6 Method 2036 Condition Condition E; not applicable to UB devices. Not applicable. 4.4.3.3 Group C sample selection. Samples for subgroups in group C shall be chosen at random from any inspection lot containing the intended package type and lead finish procured to the same specification which is submitted to and passes group A tests for conformance inspection. When the final lead finish is solder or any plating prone to oxidation at high temperature, the samples for C6 life test may be pulled prior to the application of final lead finish. Testing of a subgroup using a single device type enclosed in the intended package type shall be considered as complying with the requirements for that subgroup. * 4.4.4 Group E inspection. Group E inspection shall be performed in accordance with table III herein for qualification or re-qualification only. In case qualification was awarded to a prior revision of the specification sheet that did not request the performance of table III tests, the tests specified in table III herein must be performed to maintain qualification. 4.5 Methods of inspection. Methods of inspection shall be as specified in the appropriate tables and as follows. 4.5.1 Pulse measurements. Conditions for pulse measurement shall be as specified in section 4 of MIL-STD-750. 4.5.2 Collector -base time constant. This parameter may be determined by applying an RF signal voltage of 1 volt (rms) across the collector-base terminals, and measuring the ac voltage drop (Veb) with a high impedance rf voltmeter across the emitter-base terminals. With f = 63.6 MHz used for the 1 volt signal, the following computation applies: Cc (ps) = 2 x Veb (millivolts). 8 MIL-PRF-19500/426D TABLE I. Group A inspection. Inspection 1/ MIL-STD-750 Method Symbol Conditions Limit Min Unit Max Subgroup 1 2/ Visual and mechanical Inspection 3/ 2071 n = 45 devices, c = 0 Solderability 3/ 4/ 2026 15 leads, c = 0 Resistance to solvents 3/ 4/ 5/ 1022 15 devices, c = 0 Temperature cycling 3/ 4/ 1051 Test condition C, 25 cycles. n = 22 devices, c = 0 Heremetic seal 4/ Fine leak Gross leak 1071 n = 22 devices, c = 0 Electrical measurements 4/ Bond strength 3/ 4/ Group A, subgroup 2 2037 Precondition TA = +250°C at t = 24 hrs or TA = +300°C at t = 2 hrs. n = 11 wires, c = 0 Breakdown voltage, collector to emitter 3011 Bias condition D; IC = 1.0 mA dc, IB = 0 V(BR)CEO Collector to base cutoff current 3036 Bias condition D; VCB = 30 Vdc ICB02 100 µA dc Emitter to base cutoff current 3061 Bias condition D; VEB = 3 Vdc IEB02 100 µA dc Collector to base cutoff current 3036 Bias condition D; VCB = 20 V dc, IE = 0 ICB01 Forward-current transfer ratio* 3076 VCE = 10 V dc; IC = 0.5 mA dc; hFE1 15 Forward-current transfer ratio* 3076 VCE = 10 V dc; IC = 2.0 mA dc; hFE2 20 Forward-current transfer ratio* 3076 VCE = 10 V dc; IC = 5.0 mA dc; hFE3 30 Subgroup 2 See footnotes at end of table. 9 30 V dc 100 165 nA dc MIL-PRF-19500/426D * TABLE I. Group A inspection - Continued. Inspection 1/ MIL-STD-750 Method Subgroup 3 Symbol Conditions Limit Min Unit Max TC = +150°C High temperature operation: Collector to base cutoff current 3036 Low temperature operation: Forward-current transfer ratio Bias condition D; VCE = 20 V dc, IE = 0 100 ICB02 µA dc TA = -55°C 3076 VCE = 10 V dc; IC = 5 mA dc; hFE4 10 Magnitude of commonemitter small-signal shortcircuit forward-current transfer ratio 3306 VCE = 10 V dc; IE = 2.0 mA dc; f = 100 MHz; case lead grounded |hfe| 12 Collector to base feedback capacitance 3236 VCB = 10 V dc; IE = 0; 100 kHz ≤ f ≤ 1 MHz; case and emitter leads shall be guarded Ccb Collector to base time constant (2N4957 only) 3236 VCB = 10 V dc; IE = 2.0 mA dc; f = 63.6 MHz; case and emitter leads shall be grounded (see 4.5.2 and figure 3) rb'Cc Collector to base time constant (2N4957UB only) 3236 VCB = 10 V dc; IE = 2.0 mA dc; f = 63.6 MHz; case and emitter leads shall be grounded (see 4.5.2 and figure 3) rb'Cc Noise figure 3246 VCE = 10 V dc; IC = 2.0 mA dc; f = 450 MHz; RL = 50 Ω; case lead shall be grounded (see figure 4) NF Common-emitter small signal power gain 3256 VCE = 10 V dc; C = 2.0 mA dc; f = 450 MHz; case lead shall be grounded (see figure 4) GPE Subgroup 4 36 0.8 pF 1.0 8.0 ps 1.0 16.0 ps 3.5 dB 25 dB 17 Subgroups 5, 6, and 7 Not applicable 1/ For sampling plan (unless otherwise specified), see MIL-PRF-19500. 2/ For resubmission of failed subgroup A1, double the sample size of the failed test or sequence of tests. A failure in group A, subgroup 1 shall not require retest of the entire subgroup. Only the failed test shall be rerun upon submission. 3/ Separate samples may be used. 4/ Not required for JANS devices. 5/ Not required for laser marked devices. 10 MIL-PRF-19500/426D TABLE II. Groups B and C electrical end-point inspection measurements. 1/ 2/ 3/ 4/ Step Inspection MIL-STD-750 Method 1/ 2/ 3/ 4/ Symbol Conditions Limits Min 1. Collector to base cutoff current 3036 Bias condition D; VCB = 20 V dc, IE = 0 ICB01 2. Collector to base cutoff current 3036 Bias condition D; VCB = 20 V dc, IE = 0 ∆ICB01 3. Forward current transfer ratio 3076 IC = 5 mA dc, VCE = 10 V dc hFE3 30 4. Forward current transfer ratio 3076 IC = 5 mA dc, VCE = 10 V dc ∆hFE3 30 Unit Max 100 nA dc ±100 percent of initial value or 10 nA dc, whichever is greater. 165 ±20 percent change from initial reading. The electrical measurements for table VIa (JANS) of MIL-PRF-19500 are as follows: a. Subgroup 3, see table II herein, steps 1 and 3. b. Subgroup 4 and 5, see table II herein, steps 1, 2, 3, and 4. The electrical measurements for group B of 4.4.2.2 herein (JAN, JANTX, and JANTXV) are as follows: a. Steps 1, 2, and 3, of 4.4.2.2, see table II herein, all steps. The electrical measurements for table VII (JANS) of MIL-PRF-19500 are as follows: a. Subgroup 2, see table II herein, steps 1 and 3. b. Subgroups 6, see table II herein, steps 1, 2, 3 and 4. The electrical measurements for group C, 4.4.3.2 herein (JAN, JANTX, and JANTXV) are as follows: a. Step 2 of 4.4.3.2, see table II herein, steps 1 and 3. 11 MIL-PRF-19500/426D * TABLE III. Group E inspection (all quality levels) - for qualification only. Inspection MIL-STD-750 Method Qualification Conditions 45 devices c=0 Subgroup 1 Temperature cycling (air to air) 1051 Hermetic seal 1071 Test condition C, 500 cycles Fine leak Gross leak See group A, subgroup 2 and table II herein. Electrical measurements 45 devices c=0 Subgroup 2 Intermittent life 1037 Electrical measurements VCB = 10 V dc, 6000 cycles See group A, subgroup 2 and table II herein. Subgroups 3, 4, 5, 6, and 7 Not applicable Subgroup 8 Reverse stability 1033 Condition A for devices ≥ 400 V, condition B for devices < 400 V. 12 45 devices c=0 MIL-PRF-19500/426D FIGURE 3. RF amplifier for collector to base time constant tests. 13 MIL-PRF-19500/426D Values: C1, C7 C2, C4, C6 C3, C8 C5 R1 R2, R4 R3 = 1-10 pF (Variable air-piston type capacitors) = 500 pF (button type capacitors) = .4 - 6.0 pF (Variable air-piston type capacitors) = 1,000 pF = 2.7 kΩ = 1 kΩ = 20 kΩ L1 = silver-plated brass bar, 1.0 inch long by 0.25 inch o.d. (straight bar) L2 = silver-plated brass bar, 1.5 inches long by 0.25 inch o.d. Tap is 0.25 inch from collector (straight bar). L3 = 1/2 turn of AWG number 16 wire, loop o.d. approximately 0.5 inch, located 0.25 inch from, and parallel to L2. L4 = 0.22 µH The noise source is a hot-cold body, (AIL type 70 or equivalent) with a test receiver (AIL type 70 or equivalent). FIGURE 4. RF amplifier for power gain and noise figure tests. 14 MIL-PRF-19500/426D 5. PACKAGING 5.1 Packaging. For acquisition purposes, the packaging requirements shall be as specified in the contract or order (see 6.2). When actual packaging of materiel is to be performed by DoD personnel, these personnel need to contact the responsible packaging activity to ascertain requisite packaging requirements. Packaging requirements are maintained by the Inventory Control Point's packaging activity within the Military Department or Defense Agency, or within the Military Department's System Command. Packaging data retrieval is available from the managing Military Department's or Defense Agency's automated packaging files, CD-ROM products, or by contacting the responsible packaging activity. 6. NOTES (This section contains information of a general or explanatory nature that may be helpful, but is not mandatory.) 6.1 Intended use. The notes specified in MIL-PRF-19500 are applicable to this specification. 6.2 Acquisition requirements. Acquisition documents must specify the following: a. Title, number, and date of this specification. b. Issue of DoDISS to be cited in the solicitation, and if required, the specific issue of individual documents referenced (see 2.2). c. Packaging requirements (see 5.1). d. Lead finish (see 3.4.1). 6.3 Qualification. With respect to products requiring qualification, awards will be made only for products which are, at the time of award of contract, qualified for inclusion in Qualified Manufacturers' List (QML) whether or not such products have actually been so listed by that date. The attention of the contractors is called to these requirements, and manufacturers are urged to arrange to have the products that they propose to offer to the Federal Government tested for qualification in order that they may be eligible to be awarded contracts or orders for the products covered by this specification. Information pertaining to qualification of products may be obtained from Defense Supply Center, Columbus, ATTN: DSCC-VQE, P.O. Box 3990, Columbus, OH 43216-5000. * 6.4 Changes from previous issue. The margins of this specification are marked with asterisks to indicate where changes from the previous issue were made. This was done as a convenience only and the Government assumes no liability whatsoever for any inaccuracies in these notations. Bidders and contractors are cautioned to evaluate the requirements of this document based on the entire content irrespective of the marginal notations and relationship to the last previous issue. Custodians: Army - CR Navy - EC Air Force - 11 DLA - CC Preparing activity: DLA - CC (Project 5961-2576) Review activities: Army - AR, MI Navy - SH Air Force - 19 15 STANDARDIZATION DOCUMENT IMPROVEMENT PROPOSAL INSTRUCTIONS 1. The preparing activity must complete blocks 1, 2, 3, and 8. In block 1, both the document number and revision letter should be given. 2. The submitter of this form must complete blocks 4, 5, 6, and 7. 3. The preparing activity must provide a reply within 30 days from receipt of the form. NOTE: This form may not be used to request copies of documents, nor to request waivers, or clarification of requirements on current contracts. Comments submitted on this form do not constitute or imply authorization to waive any portion of the referenced document(s) or to amend contractual requirements. 1. DOCUMENT NUMBER 2. DOCUMENT DATE MIL-PRF-19500/426D 28 December 2001 I RECOMMEND A CHANGE: 3. DOCUMENT TITLE SEMICONDUCTOR DEVICE, TRANSISTOR, PNP, SILICON, AMPLIFIER TYPE 2N4957 AND 2N4957UB JAN, JANTX, JANTXV, AND JANS 4. NATURE OF CHANGE (Identify paragraph number and include proposed rewrite, if possible. Attach extra sheets as needed.) 5. REASON FOR RECOMMENDATION 6. SUBMITTER a. NAME (Last, First, Middle initial) b. ORGANIZATION c. ADDRESS (Include Zip Code) d. TELEPHONE (Include Area Code) COMMERCIAL DSN FAX EMAIL 7. DATE SUBMITTED 8. PREPARING ACTIVITY a. Point of Contact Alan Barone c. ADDRESS Defense Supply Center, Columbus ATTN: DSCC-VAC P.O. Box 3990 Columbus, OH 43216-5000 DD Form 1426, Feb 1999 (EG) b. TELEPHONE Commercial DSN FAX EMAIL 614-692-0510 850-0510 614-692-6939 [email protected] IF YOU DO NOT RECEIVE A REPLY WITHIN 45 DAYS, CONTACT: Defense Standardization Program Office (DLSC-LM) 8725 John J. Kingman, Suite 2533 Fort Belvoir, VA 22060-6221 Telephone (703) 767-6888 DSN 427-6888 Previous editions are obsolete WHS/DIOR, Feb 99