1N5820, 1N5821, 1N5822 125 125 20 15 20 ° 10 ° 15 10 115 8.0 115 8.0 TURE ( C) TURE ( C) 105 105 R R TEMPERA qJA (°C/W) = 70 TEMPERA qJA (°C/W) = 70 95 50 95 50 40 40 28 28 , REFERENCE 85 , REFERENCE 85 R R T T 75 75 2.0 3.0 4.0 5.0 7.0 10 15 20 3.0 4.0 5.0 7.0 10 15 20 30 VR, REVERSE VOLTAGE (VOLTS) VR, REVERSE VOLTAGE (VOLTS) Figure 1. Maximum Reference TemperatureFigure 2. Maximum Reference Temperature1N58201N5821 125 40 20 MAXIMUM ° 35 15 TYPICAL 115 10 30 ANCE TURE ( C) ° 8.0 105 25 RESIST 20 O-LEAD ( C/W) TEMPERA Rq 95 JA (°C/W) = 70 15 50 , THERMAL JL 10 85 40 q JUNCTION-T R BOTH LEADS TO HEATSINK, REFERENCE R 5.0 T 28 EQUAL LENGTH 75 0 4.0 5.0 7.0 10 15 20 30 40 0 1/8 2/8 3/8 4/8 5/8 6/8 7/8 1.0 VR, REVERSE VOLTAGE (VOLTS) L, LEAD LENGTH (INCHES) Figure 3. Maximum Reference TemperatureFigure 4. Steady-State Thermal Resistance1N5822 1.0 The temperature of the lead should be measured using a ther‐ LEAD LENGTH = 1/4″ mocouple placed on the lead as close as possible to the tie point. ANCE 0.5 The thermal mass connected to the tie point is normally large 0.3 enough so that it will not significantly respond to heat surges RESIST 0.2 generated in the diode as a result of pulsed operation once Ppk Ppk DUTY CYCLE = t steady-state conditions are achieved. Using the measured t p/t1 p PEAK POWER, P 0.1 value of T pk, is peak of an L, the junction temperature may be determined by: TIME equivalent square power pulse. THERMAL TJ = TL + DTJL t1 (NORMALIZED) 0.05 DTJL = Ppk • RqJL [D + (1 - D) • r(t1 + tp) + r(tp) - r(t1)] where: DTJL = the increase in junction temperature above the lead temperature. 0.03 r(t) = normalized value of transient thermal resistance at time, t, i.e.: 0.02 r(t1 + tp) = normalized value of transient thermal resistance at time r(t), TRANSIENT t1 + tp, etc. 0.01 0.2 0.5 1.0 2.0 5.0 10 20 50 100 200 500 1.0 k 2.0 k 5.0 k 10 k 20 k t, TIME (ms) Figure 5. Thermal Responsehttp://onsemi.com5