VUUAUUAUNAU UATE CONVENTIONAL UNISUNCTIONS General Electric produces a very broad line of standard UJTs. The TO-5 ceramic disc bar structure device has been the workhorse of the unijunction industry for over 10 years. MIL versions are available on the 2N489-494 series. The cube structure TO-18 series offers excellent value for those requiring proved, low cost units. Applications Oscillators SCR Triggers Timers Frequency Divider Sawtooth Generators Stable Voltage Sensing Rno te leo Vos, interbase n \Wv Peak Point Emitter Base One Resistance intrinsic Valley Emitter Reverse Current Peak Pulse = 3V Standoff Current Current Voltage GE le = 0 Ratio Min. Max, Max. T2=25C Min. Comments Type @ Vos = 10V (mA) (uA) (uA) 7) Package 2N489 2N489/ * i -51-.62 2N4690 2N490 2N490A * 2N49068 2N4906 2N491 2N4914 * 2N4916 2N492 2N492A\ * 2N492B 2N4926 2N493 2N493/A * 2N493B 2N494 2N494A * 2N494B 2N494C 2N1671 2N1671A 2N1671B 2n1671C 2N2160 2N2646 .56-.75 10-5 Bar Structure 10-18 Cube Structure 2N2840 -62 Typical * JAN & JANTX types available 2 Vee=1.5V 124Silicon Unijunction Transistors a Go 2N489-94,A,B The General Electric Silicon Unijunction Transistors are three-terminal devices having a stable N type negative resistance characteristic over a wide temperature range. A stable peak point and a high peak current rating make these devices useful in oscillators, timing circuits, trigger circuits, and bistable circuits, where it can serve the purpose of two conventional silicon transis- tors. General Electrics FixedBed Construction makes these transistors extremely reliable under severe conditions of mechanical shock, vibration, centrifugal force, and thermal shock. It also provides a lower terminal resistance and improved uniformity of electrical characteristics. These transistors are hermetically sealed in welded cases. 3 o PERCENT CHANGE IN FREQUENCY Nn oF ' nN -4 -60 -40 -20 oO +20 +40 +60 +80 +100 +120 +140 AMBIENT TEMPERATURE -Ta-OEGREES CENTIGRADE ONLY THE UNIVUNCTION SUBMITTED TO TEMPERATURE FEATURES Stable Operation over Wide Temperature Range Low Leakage Current Low Peak Point Current Guaranteed Minimum Pulse Voltage 2N489, A, B absolute maximum ratings* ON494, A. B Total RMS Power DissipationUnstabilized 450' mw Total RMS Power DissipationStabilized 600" mw RMS Emitter Current 70 ma Peak Emitter Current (T; = 150C) 2 amps Emitter Reverse Voltage (T; = 150C) 60 volts Operating Temperature Range 65 to +140 C Operating Temperature RangeStabilized? 65 to +175 C Storage Temperature Range 65 to +175 C 1. Derate 3.9 mw/C increase in amb. temp. (Thermal resistance to case = 0.16C/mw) 2. Derate 2.6 mw/C increase in amb. temp. (Thermal resistance to case = 0.08C/mw) 8. Under normal operation, thermal runaway conditions cannot exist with the UJT up to a junction temperature of 140C since the temperature coefficient of Ras is positive below this temperature and Iso is negligible. For this reason an unstabilized power rating can be used with the UJT which is derated to zero at 140C. The UJT can be used at temperatures above 140C but in this case external resistance must be used in the emitter and interbase circuits to limit the power dissipation and prevent thermal runaway. The power rating for this condition is the stabilized power rating and is derated to zero at 175C. It is also important to provide circuit stabilization in the interbase circuit when the UJT is used in pulse type applications since the instan- taneous temperature of the silicon could rise to a high enough value to permit runaway. 4. Emitter peak current should be limited to two amperes for discharge capacitances up to 104fd, with a peak point voltage of 30 volts. For higher values of C or Ve, resist- ance must be added in series with the capacitor to protect the emitter circuit. description General Electrics Silicon Unijunction Transistor consists of an N type silicon bar mounted between two ohmic base contacts with a P type emitter near base-two. The device operates by conductivity modulation of the silicon between the emitter and base-one when the emitter is forward biased. In the cutoff, or standby condition, the emitter and interbase power supplies establish potentials between the base contacts, and at the emitter, such that the emitter is back biased. If the emitter potential is increased sufficiently to overcome this bias, holes (minority carriers) are injected into the silicon bar. These holes are swept toward base-one by the internal field in the bar. The increased charge concentration, due to these holes, decreases the resistance and hence decreases the internal voltage drop from the emitter to base-one. The emitter current then increases regeneratively until it is limited by the emitter power supply. The effect of this conductivity modulation is also noticed as an effective modulation of the interbase current. *25C, unless otherwise specified. 298 DIMENSIONS WITHIN | 320 JEDEC OUTLINE TO-5 TO-5 EXCEPT FOR LEAD CONFIGURATION . 260 240 NOTE 1; Lead diameter is controlled in the 150 MIN. zone between .060 and 250 from the seat- (NOTE 4) ing plane. Between .250 and end of lead a [oo max, of 021 is held. ] WOTE 2: Leads having maximum diameter (019) measured in gaging plane 054 + .001 I | i .000 below the seating plane of the device 035 1S$00 shall be within .007 of true position ~ela- tN. tive to a maximum width tab, ( ( | NOTE 3: Measured from max, diameter of the actual device ban 20 -4\ | L seating NOTE 4: This zore Is controlled for auto- : PLANE matic handling. The variation in actual diam- NO 3 LEADS eter within this zone shall not exceed 010, $< suey es ALL DIMEN, IN INCHES AND ARE REFERENCE UNLESS TOLERANCED 82 LEaDt LEAD 4 EMITTER... EE BASE ONE...B1 045 7 BASE TWO...B2 029 (NOTE 3} 81 , as LEAD 2 2N489, A, B THROUGH 2N494, A, Belectrical characteristics: (at 25C unless otherwise noted) of +10% from the center value and each range of interbase General Electric Unijunction Transistors are specified pri- marily in three ranges of stand-off ratio and two ranges of interbase resistance. Each range of stand-off ratio has limits 2N489-94, A, B resistance has limits of +20% from the center value. MAXIMUM MINIMUM Intrinsic Modulated Emitter Peak Valley Base One Standoff Interbase Interbase Saturation Emitter Reverse Current Point Point Peak Pulse Ratio Resistance Current Voltage Current Current Voltage Type Neo. (See (See In = i Vier = ;= Veer = | Van = 25V Rre = | (See note 3) note 1) note 2) 50 ma 50 ma 60V 150C 30V 1002 Viz = Vin = Viz = Vara = Ver == Vasa = 10V 3V }OV 10V 10V 20V Repro Iba mop) Viewsat) lzpeo lepen leBeo Ip ly Vosi n ohms ma volts pa pa wa pa ma volts TO-5 Min. Max.) Min. Max.|) Min. Max. 2N489 51.62/47 68/68 22 5 2 20 12 8 2N489A | 51 62/47 68/68 22 4 2 20 12 8 3 2N4g0B | 51 .62]).4.7 68/68 22 4 2 20 0.2 6 8 3 2N490 51. 624 6.2 94)]6.8 22 5 2 20 12 8 2N490A | .B1 .62| 6.2 9.1] 6.8 22 4 2 20 12 8 3 2N490B | .51 .62| 62 91/68 22 4 2 20 0.2 6 8 3 2N491 56 .68| 4.7 6.8/6.8 22 3 2 20 12 8 2N491A | 56 68] 4.7 68/68 22 4.3 2 20 12 8 3 2N4o1B | 56 68/47 68/68 22 4.3 2 20 0.2 6 8 3 2N492 6.8 22 5 2 20 12 8 2N492A | . 6.8 22 4.3 2 20 12 8 3 2N492R 6.8 22 4.3 2 20 0.2 6 8 3 2Nag | 62 6.8 22 5 2 20 12 8 BNA98A | 62 6.8 22 4.6 2 20 12 8 3 493B 6.8 22 4.6 2 20 0.2 6 8 3 2N494 22 5 2 20 12 8 -QN494A | 62. 22 4.6 2 20 12 8 3 -eN404B | 62 29 4.6 2 20 0.2 6 8 3 , Vv notes: +20vt5V 1. The intrinsic standoff ratio, , is essentially constant with temperature and interbase volt- age. 7 is defined by the equation: 200 T; Vp = 7 Vas + Where Ve = Peak point emitter voltage Vas = Interbase voltage T; = Junction Temperature (Degrees Kelvin) 2. The interbase resistance is nearly ohmic and increases with temperature in a well de- fined manner. The temperature coefficient at 25C is approximately 0.8%/C. 3. The base-one peak. pulse voltage is meas- ured in the circuit at right. This specification on the A and B versions is used to ensure a minimum pulse amplitude for applications in SCR firing circuits and other types of pulse circuits. 299 \| = C, O.2ufd25% -5 Voa! | Rei 202L1%[_2N489-94, A, B lEMITTER CHARACTERISTICS -CUTOFF REGION Pp NEGATIVE RE SISTANCE wl SATURATION ~ EGION t REGION i to 8 9OTH PERCENTILE , EMITTER TO BASE-~ x Vaptlov | ONE ra | GHARACTERISTI 3 ' tai n | WALLEY POINT 9 lo & Vg (SAT )-[-/-1-- ~- Sar - 46 ---- ==> Z = tot UPPER LIMIT Ww ' a FOR "B VERSIONS _______1__ -2 soma TE er 8 5 Teo uw 2 = & 2 3 gs Tat + 25C . . oa: wy 1 c Ia)z0 Static Emitter Characteristic curves show- g 8 a ing important parameters and measure- : = ment points (exaggerated to show details). = = 1o-? -4, e 10 r 18 = = = 3 WwW 16 io MEDIAN ALL TYPES I o STATIC EMITTER CHARACTERISTICS 5 Tat - 55C gt io - ; 60-20 +20 +6002 +100 +140 1o3y Zo 40 30 AMBIENT TEMPERATURE - Ta - DEGREES CENTIGRADE EMITTER BASE TWO REVERSE VOLTAGE -Vp,-VOLTS "y w 8 , a Vee" 30V 5 EMITTER REVERSE CURRENT CHARACTERISTICS o > Vae* a x E 5 = v jov 3 o 88 ~ 3 000 MEASURED VALUES ws CALCULATED VALUES <50k z V_e-Vp# A+B LOG Ip -IeRnp wen - g Ve 0-D+-W.-0 + Vag, > 7 1g,70 S Treo Rup (Rype5.6K) =+ o\ Qo 2 4 6 6 Te} 12 14 16 18 20 = -O.l all EMITTER CURRENT - [ - MILLIAMPERES a | Vag *!5V z Ta 225C A 5-02 Try g a & <1 4 -03 a 8 -04 a o STATIC EMITTER CHARACTERISTICS re Tas +25C FE $ = -05 ' 230V iw > ws g Vea20v 0.01 ol t 10 100 3 EMITTER CURRENT -I - MICROAMPERES > & Ven stOv E STATIC EMITTER CHARACTERISTICS z Vas *5V AT PEAK POINT a 2 I Be Oo oO 2 4 6 10 14 is 1g 20 WW EMITTER CURRENT -T_ - MILLIAMPERES 8 a 2 = 1 = Ww a STATIC EMITTER CHARACTERISTICS = 5 Tat tl25C F a > ad ' & Veg = 30V yw 868 = a B J, 7125 . Ven = 20V g w Ta 225 E 4 : Nee e on co c- o = 55C 00! Ol A { to Ty, CAPACITANCE -C; -MICROFARADS EMITTER CURRENT - Ie - MILLIAMPERES STATIC EMITTER CHARACTERISTICS EMITTER VOLTAGE FALL TIME VS. CAPACITANCE IN RELAXATION OSCILLATOR/*SLOPE*R550 1 -50MA Tgg(MO0) 90% LIMITS a Ta=t+ 25C Rapo 4.7K INTERBASE CHARACTERISTICS AT ANY AMBIENT TEMPERATURE MAY BE DETERMINED BY DIVIDING THE HORIZONTAL SCALE BY THE NORMALIZED INTERBASE RESISTANCE (Kr) 2N489-94, A, B STATIC CHARACTERISTICS Ta = -55C Ig "IOMA Te * 30MA Tg = (OMA STATIC INTERBASE CHARACTERISTICS Tah = +25C = 20MA STATIC INTERBASE CHARACTERISTICS Ty * +125C Ig * 20ma Ig 30ma Te *40moa o . XN [| 8 NI t + N\ |-90 TH PERCENTILE \ PERCENTILE w \ AKA MEDIAN-+ ix) o IN \ VALLEY POINT CURRENT - Iy-MILLIAMPERES PEAK POINT CURRENT - Ip-MICROAMPERES 10 Ta =-55C 1.0 0.8 0 5 10 15 20 25 30 INTERBASE VOLTAGE-VggVOLTS os I 2 3. 4 6 8 10 20 30 40 INTERBASE VOLTAGE - Vag - VOLTS 30 10 | g a c 8 WW wu NN : Co 90TH PERCENTILE ? wi \ a +] a 6 2 NO = 20 Tas +25C 4 NN 9OTH PERCENTILE . | - MEDIAN 8 4 \. 7 a I \ r = Ta? +25C 2 t Zz Eo x 2 2 MINIMUM LIMIT I" "FOR ALL TYPES 3 a FE MEDIAN 3 a z > Z \ * 190 N 05 5 208 10 5 20 25 30 35 a. INTERBASE VOLTAGE - Vgg - VOLTS 0.6) 2 30064 6 a 10 20 30 40 INTERBASE VOLTAGE -Vgg- VOLTS 90TH PERCENTILE Tattl25C 90TH PERCENTILE Ta* +125C MEOIAN PEAK POINT CURRENT -Ip- MICROAMPERES VALLEY POINT CURRENT - ly - MILLIAMPERES 96 | 2 304 6 8 10 20 30 40 5 10 15 20 25 30 35 INTERBASE VOLTAGE - Vag - VOLTS INTERBASE VOLTAGE -Vgg- VOLTS as Vas VARIATION OF |, WITH Vzz ee t T T T NORMALIZED Ig, (MOD) VS Vgp | | n i | is T T T T | NORMALIZED Ig, (MOD) VS TEMP NORMALIZED Ve (sary VS Vep\ 1 NORMALIZED Veg, (gat) VS Temp Ns : Tg = 5OMA aS = i en a - | a Lo t | ane | oe fp | i Lt ee a __T | naan [eee 3022N489-94, A, B, 2N489 2N494 A AND B VERSIONS SCR TYPE 90% LIMITS 2N1909-1916 35,C36, 2N68I-689 2NI842-1880 ct0,cu1 2NI770-1777 ENG AT2E 10% SPRAGUE 312204 270 t 10% SPRAGUE 312204 AB VERSIONS Vee 220 VOLTS Tas 25C 55C TO+ 125C Vag *25 VOLTS + #0.68 -TRIGGER AT BASE - TWO REFERENCES: 1. Notes on the Application of the Silicon Unijunc- tion Transistor, 90.10. 2. General Electric Controlled Rectifier Manual, Fifth Edition. + TRIGGER AT EMITTER 303