High-reliability discrete products and engineering services since 1977 MU4891-MU4894 SILICON UNIJUNCTION TRANSISTOR FEATURES Available as “HR” (high reliability) screened per MIL-PRF-19500, JANTX level. Add “HR” suffix to base part number. Available as non-RoHS (Sn/Pb plating), standard, and as RoHS by adding “-PBF” suffix. MAXIMUM RATINGS. Rating Symbol Value Unit Power dissipation PD 300 mW RMS emitter current IE 50 mA iE 1.0 Amps (1) Peak pulse emitter current (2) Emitter reverse voltage VB2E 30 Volts Storage temperature range Tstg -65 to 150 °C Note 1: Derate 3mW/°C increase in ambient temperature. The total power dissipation must be limited by the external circuitry. VB2B1 = √(RBB · PD) Note 2: Capacitance discharge must fall to 0.37 Amp within 3.0ms and PRR ≤ 10PPS. ELECTRICAL CHARACTERISTICS (TC = 25°C unless otherwise noted) Parameter Symbol Intrinsic standoff ratio (VB2B1 = 10V) (1) MU4892 MU4891, MU4893 MU4894 Interbase resistance (VB2B1 = 3V, IE = 0) MU4891, MU4892 MU4893, MU4894 Interbase resistance temperature coefficient (VB2B1 = 3V, IE = 0, TA = -65° to 100°C) η RBB αRBB Emitter saturation voltage (VB2B1 = 10V, IE = 50mA)(2) VEB1(sat) Modulated interbase current (VB2B1 = 10V, IE = 50mA) IB2(mod) Emitter reverse current (VB2E = 30V, IB1 = 0) Peak point emitter current (VB2B1 = 25V) Valley point current (VB2B1 = 20V, RB2 = 100ohms)(2) Base-one peak pulse voltage(3) Figure 3 IEB2O MU4891 MU4892, MU4893 MU4894 IP Min Typ Max 0.51 0.55 0.74 - 0.69 0.82 0.86 4.0 4.0 7.0 7.0 9.1 12.0 0.1 - 0.9 - 2.5 4.0 10 15 - - 5.0 10 - 0.6 0.6 0.6 5.0 2.0 1.0 Unit - kΩ %/°C Volts mA nA µA MU4891, MU4893, MU4894 MU4892 IV 2.0 2.0 4.0 3.0 - mA MU4891, MU4892, MU4894 MU4893 VOB1 3.0 6.0 5.0 8.0 - Volts Note 1: Intrinsic standoff ratio: η = (VP-VEB1)/VB2B1, where VP = peak point emitter voltage , VB2B1 = interbase voltage, VEB1 = emitter to base one junction diode drop (≈ 0.5V @ 10µA). Note 2: PW ≈ 300µs, duty cycle≤ 2% to avoid internal heating due to interbase modulation which may res ult in erroneous readings Note 3: Base one peak pulse voltage is used to ensure minimum pulse amplitude for applications in SCR firing circuits and other types of pulse circuits. Rev. 20121009 High-reliability discrete products and engineering services since 1977 MU4891-MU4894 SILICON UNIJUNCTION TRANSISTOR MECHANICAL CHARACTERISTICS Case TO-92 Marking Alpha-numeric Pin out: See below Rev. 20121009