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 Gt iI 2N1671,1A,B,C The General Electric Silicon Unijunction Transistor is a three terminal device having a stable N type negative resistance characteristic over a wide temperature range. A stable peak point voltage, a low peak point current, and a high pulse current rating make this device useful in oscillators, timing circuits, trigger circuits and pulse generators where it can serve the purpose of two conventional silicon or ger- manium transistors, The 2N1671 is intended for general purpose industrial applications where circuit economy is of primary importance. The 2N1671A is intended for industrial use in firing circuits for Silicon Controlled Rectifiers and other applications where a guaranteed minimum pulse amplitude is required. The 2N1671C is intended for applications where a low emitter leakage current and a low peak emitter current (trigger current) are required. These transistors feature Fixed-Bed Construction and are hermetically sealed in a welded case. All leads are electrically isolated from the case. _. S7TOMAX___ 360MIN ] | 335MAX [ 325 MIN absolute maximum ratings (25C) diameter within this zone shall not exceed {ROMIN 260MAXK WOTE 1: This zone is controlled for auto: I matic handling. The variation in actual f 010. (NOTE!) 250MIN RMS Power Dissipation 450 mw! WOTE 2: Measured from max. diameter of Po the actual device, Cc ne + RMS Emitter Current 50 ma WOTE 3: The specified lead diameter ap ples in the zone between .050 and 250 | 15MIN . 2 from the base seat. Between .250 and 1.5 j Peak Emitter Current 2 amperes mranimum of O21 duameter i held. utside [ [ (td * of these zones the lead diameter 1s not i | Emitter Reverse Voltage 30 volts controled 200 2.010 Be : : Interbase Voltage 35 volts LEAD (o~\ LEAD! Operating Temperature Range 65C to +140C Storage Temperature Range 65C to +150C BI EMITTER. ..E LEAD 2 BASE ONE..BI } GOLD LEADS BASE TWO..B2} 017 +-99? Kp 5 7 O31 4.003 90 SX on SO mee . . . {NOTE 3} electrical characteristics (25C) 2N1671/ 2N1671AI2N1671B/2N1671C PARAMETER SYMBOL MIN. MAX. |) MIN. MAX. | MIN, MAX. | MIN. MAX. UNITS Intrinsic Standoff Ratio (Vse = 10V) (Note 3) n 0.47 0.62 0.47 0.62 0.47 0.62 0.47 0.62 Interbase Resistance (Vax = 3V, In = 0) (Note 4) Rago 47 91 4.7 91 4.7 91 4.7 91 K Emitter Saturation Voltage (Vas = 10V, I: == 50 ma) Vu(SAT) 5 5 5 5 volts Modulated Interbase Current (Vss = 10V, Iz = 50 ma) Inz(MOD) | 6.8 22 6.8 22 6.8 22 6.8 22 ma Emitter Reverse Current (Vase = 30V, In. = 0) (Fig. 6) Tro 12 12 0.2 02 pa Peak Point Emitter Current (Vas = 25V) (Fig. 8) Ip 25 25 6 2 wa Valley Point Current (Van = 20V, Re: = 1002) (Fig. 9) Iy 8 8 8 8 ma Base-One Peak Pulse Voltage (Note 5) Vor 3.0 3.0 3.0 volts Emitter Reverse Current (Vas=25V, Vem=Vr.3V) (Fig.3) | Tex 0.05 wa NOTES: (1) Derate 8.9 MW/C increase in ambient tem- perature (Thermal resistance to case (4) The interbase resistance is nearly ohmic and increases with temperature in a well defined man- =0.16C/MW.) (2) Capacitor discharge10zfd or less, 30 volts or lessTotal interbase power dissipation must be limited by external circuitry. (3) The intrinsic standoff ratio, 7, is essentially constant with temperature and interbase voltage. n is defined by the equation: Ve=nVas + oe aI Vr=Feak point emitter voltage Varzzinterbase voltage T;Junction Temperature (Degrees Kelvin) Where ner as shown in figures 10 and 11. The temperature coefficient at 25C is approximately 0.8%./C. (5) The base-one peak pulse voltage is measured in the circuit below. This specification on the 2N1671A is used to ensure a minimum pulse ampli- tude for applications in SCR firing circuits and other types of pulse circuits. The variation of pulse amplitude with temperature and circuit parameters is shown in figures 12 to 15. 3182N1671, 1A, B, C NEGATIVE + - CUTOFF RESISTANCE ->!4- SATURATION REGION REGION REGION Vp VY PEAK POINT ONE DIODE CHARACTERISTIC i \ ' | EMITTER TO BASE~ | | | | | EMITTER VOLTAGE GELOW PEAK POINT (vp - vp VOLTS: 0.008 oo on t 10 100 EMITTER CURRENT - Ig - MICROAMPERES. FIG. 1 FIG. 2 FIG. 3 Unijunction Transistor Symbol with No- Static Emitter Characteristic curves show- Static Emitter Characteristics at Peak Point. menclature used for voltage and currents. ing important parameters and measure- ment points (exaggerated to show details). Ta 125C o wn 5 5 2 $ 8 2 + ; S$ ~~ # \ 1 ony a w g F o w <q 5 o = 3 = 3 Y 2 3 FE 6 E6 & eB . = e 5 Yap" 1OV z E Fe a Tgp 70 2. 4 6 8 WO 1 14 i620 EMITTER CURRENT Ig MILLIAMPERES EMITTER CURRENT-I- MILLIAMPERES EMITTER CURRENT-Ip-MILLIAMPERES FIG. 4 Static emitter characteristics for a typical 2N1671 unijunction transistor at . three different ambient temperatures. ap Ta 25C 45 spe wep : = 125 Ta 2~55C Tq = 125C ip 1OMA FS VOLTAGE -Vgp -VOLTS INTERBASE VOLTAGE - Va, -VOLTS INTERBASE VOLTAGE - Vgg- VOLTS INTERBASE 6 8 10 12 14 16 18 20 22 4 BASE - TWO CURRENT-L po MILLIAMPERES BASE TWO CURRENT Ig, MILLIAMPERES BASE TWO CURRENT- Ip, -MILLIAMPERES FIG. & Static interbase characteristics for a typical 2N1671 unijunction transistor , at three different ambient temperatures. 319[_ 21671, 14,8, C | INTERBASE RESISTANCE NORMALIZED wn wd ec yi 10 2 = & BNET, 2NE 9 = - i a pen? H ering 1 en 5 ue & 4 107 x w wen a x i lo- 7 Ve2e= 30V f E = ul 20 40 #60 80 00 120 MO 160 AMBIENT TEMPERATURE ~ Ta -DEGREES CENTIGRADE FIG. 6 Emitter reverse current vs. temperature. Te-55C T, 725C Ta rl2sc PEAK POINT EMITTER CURRENT- Ip -MICROAMPERES ' 2 3.94567 #0 (5 20 30 40 INTERBASE VOLTAGEVg_ VOLTS FIG. 8 Peak Point Emitter Current vs. interbase veltage and ambient temperature for a typical unit. 22 06 O4 -60 -40 -20 20 40 60 60 wo 120) 140 JUNCTION TEMPERATURE -Ty ~DEGREES CENTIGRADE FIG. 10 Normalized interbase resistance vs. junc- tion temperature. 160 320 EMITTER VOLTAGE FALL TIME-t, ~MICROSECONDS Oot POINT CURRENT-Iy -MILLIAMPERES VALLEY INTERBASE CURRENT~Ipo-. MILLIAMPERE S =-55C Ol A { 0 CAPACITANCE -C; -MICROFARADS FIG. 7 Emitter voltage fall time vs. capacitance and ambient temperature for a typical unit in relaxation oscillator circuit. Ty 55C Ty r25C Ta 25C MINIMUM LIMIT FOR ALL TYPES INTERBASE VOLTAGE ~ Vag VOLTS FIG. 9 Valley Point Current vs. interbase voltage and ambient temperature for a typical unit. UNIT IN FREE AIR EMITTER OPEN CIRCUITED UMITS Ta =,25C 5 10 1S. 20 26 30 35 40 INTERBASE VOLTAGE Vaa- VOLTS FIG. 11 Limit values of static interbase characteris- tics with zero emitter current.NORMALIZED BASE-ONE PEAK PULSE VOLTAGE MINIMUM 8ASE-ONE PEAK PULSE VOLTAGEVog, ~ VOLTS 2.6 2. 2. 2.0 8 1.6 1.4 2 1.0 B=] 0. 04 0. 0. 2N1671A - 2N1671B 2N1671, 1A, B, C GENERAL PURPOSE PULSE CIRCUITS AND FIRING CIRCUITS FOR SILICON CONTROLLED RECTIFIERS o 587 20 VOLTS Tye 25C ~ a wo 0.01 0.02 0.05 ol o2 O58 ' 2 F lo CAPACITANCE C, MICROFARADS FIG. 12 Minimum base-one peak pulse voltage vs. capacitance and base-one resistance in relaxation oscillator circuit. 4 2NIG67IA-2NIG67IB 2 6 2 0 5 10 5 20 2 30 35 40 INTERBASE VOLTAGE-V, "VOLTS FIG. 14 Normalized base-one peak pulse voltage vs. interbase voltage in relaxation oscillator circuit. AC Dc FIG. 16 Basic unijunetion transistor firing circuit for silicon controlled rectifiers. 321 w T T T 2NIG7IA - 2NIG7IB m SHADED AREA INDICATES he A WocaTes | uy 09 Um. 0 . AN O07 uf 06 : N f 6 NORMALIZED BASE-ONE PEAK PULSE VOLTAGE -50 -25 25 50 75 100 125 150 AMBIENT TEMPERATURE - Ty - DEGREES FIG. 13 Normalized base-one peak pulse voltage vs. temperature in relaxation oscillator circuit. CENTIGRADE UIT TYPE SCR TYPE CURVE Ri Viowant ce0l2N2023-30) 5S AND C56 a 270 20% aay 2naeaa 8 B 52r2ni792-96) THROUGH C50(2NI909-16) 2N494A, B, AND C cag a 470 20% zev {ALSO USAF TYPES) ges, PULSE TRANS, C36(2NiIe42-S0t era2 asv c40 2 27a > 1% ov 3a" 2 engaiza ae SRrensai-sar a 20v ROUGH 30 AND c3Zm 2N24222, B, AND C 38 ane CBee 6 PULSE TRANS. 380 as SPRAGUE 312204 ce ma 2N16714, 8, AND C CL2NI7 70-78, 270 0% sev 2nz619) ClIOLANI77OA- 7A) co 6 ara 10% iv 2N2646 9(2N1929~35) 2NI698-99. t PULSE TRANS. ev SPRAGUE 317204 C7(2N2344- 48} F {50 2 0% 38v, 2nzea7 ce " ara 2 0% 20v 8 2 SPRAGUE 312204 35v NOTES! MLIMITED TO 27 VOLTS WAX ON "O" CURVE AND IS KAM MINIMUM TRIGGER PULSE (S TWICE THE AMP- VOLTS ON "E CURVE. LITUDE OF O1MERA UJT'S, THIS ASSURES 2:1 METRIGGER REQUIREMENTS LESS THAN OTHERS OVER MINIMUM SOR TRIGGER FEQUIREMENTS. In THIS GROUP 36 T Tih 34 . ft - + e \al | Oo} | I ia) 3 t r r tt 2 ! gt I WACNC To i 2af \\ 1 - > wb 26, ~- | TN 2 # 24 . 2 : * 22 2 20 a 18 @ z 6+ 2 z 4 * zb-- [4 0 za ss5"c Tow iasec | || | SNOTE: Temperoture ange may + | +: g Lbt restricted by the SCR } i i Tr oo ol 1 10 CAPACITANCE -C,- MICROFARADS Fic. 15 Minimum supply voltage required to fire standard types of silicon controlled rectifiers vs. capacitance in circuit below. Period of Relaxation Oscillator 7=0.80 R:Ci (+ 0.21 R:Gi) Maximum Value of R: for oscillation (55C to +140C ) Ri (max) = 430 V2 (2N1671-2N1671A) Ri (max) = 1800 V.2 (2N1671B) 7 = Period in Seconds C, = Capacitance in Farads R, = Resistance in ohms V.= Supply voltage in volts REFERENCES: 1. Notes on the Application of the Silicon Unijunc- tion Transistor, 90.10. 2. General Electric Controlled Rectifier Manual, Fifth Edition.