2N2646
Unijunction Transistor
TO−18 Package
Description:
The 2N2646 is designed for use in pulse and timing circuits, sensing circuits and thyristor trigger circuits.
Features:
DLow Peak Point Current: 5A (Max)
DLow Emitter Reverse Current: .005A (Typ)
DPassivated Surface for Reliability & Uniformity
Absolute Maximum Ratings: (TA = +25C unless otherwise specified)
Power Dissipation (Note 1), PD300mW...................................................
RMS Emitter Current, IE(RMS) 50mA......................................................
Peak Pulse Emitter Current (Note 2), iE2A................................................
Emitter Reverse Voltage, VB2E 30V.......................................................
Interbase Voltage, VB2B1 35V............................................................
Operating Junction Temperature Range, TJ−65 to 125C...................................
Storage Temperature Range, Tstg −65 to +150C..........................................
Note 1 Derate 3mW/C increase in ambient temperature. The total power dissipation (available
power to Emitter and Base−Two) must be limited by the external circuitry.
Note 2 Capacitor discharge − 10F or less, 30 volts or less
Electrical Characteristics: (TA = +25C unless otherwise specified)
Parameter Symbol Test Conditions Min Typ Max Unit
Intrinsic Standoff Ratio VB2B1 = 10V, Note 3 0.56 −0.75 −
Interbase Resistance rBB VB2B1 = 3V, IE = 0 4.7 7.0 9.1 k
Interbase Resistance Temperature
Coefficient
arBB 0.1 −0.9 %/C
Note 3. Intrinsic standoff ratio, is defined by equation:
= VP − VF
VB2B1
where VP = Peak Point Emitter Voltage
VB2B1 = Interbase Voltage
VF = Emitter to Base−One Junction Diode Drop ( 0.45V @ 10A)
Electrical Characteristics (Cont’d): (TA = +25C unless otherwise specified)
Parameter Symbol Test Conditions Min Typ Max Unit
Emitter Saturation Voltage VEB1(sat) VB2B1 = 10V, IE = 50mA, Note 4 −3.5 −V
Modulated Interbase Current IB2(mod) VB2B1 = 10V, IE = 50mA −15 −mA
Emitter Reverse Current IEB20 VB2E = 30V, IB1 = 0 −0.005 12 A
Peak Point Emitter Current IPVB2B1 = 25V −1 5 A
Valley Point Current IVVB2B1 = 20V, RB2 = 1004 6 −mA
Base−One Peak Pulse Voltage VOB1 3 5 −V
Note 4. Use pulse techniques: Pulse Width ~300s, duty cycle 2% to avoid internal heating due
to interbase modulation which may result in erroneous readings.
.030 (.762) Max
.230 (5.84) Dia Max
.195 (4.95) Dia Max
.210 (5.33)
Max
.500
(12.7)
Min
.018 (0.45)
.041 (1.05)
45
Emitter
Base 1
Base 2/Case
