1N5822 Просмотр технического описания (PDF) - Motorola => Freescale
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1N5822 Datasheet PDF : 6 Pages
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1N5820 1N5821 1N5822
1.0
The temperature of the lead should be measured using a ther-
0.5 mocouple placed on the lead as close as possible to the tie point.
The thermal mass connected to the tie point is normally large
0.3 enough so that it will not significantly respond to heat surges
0.2 generated in the diode as a result of pulsed operation once
steady–state conditions are achieved. Using the measured val-
0.1
ue of TL, the junction temperature may be determined by:
TJ = TL + DTJL
0.05
0.03
0.02
0.01
0.2
0.5 1.0 2.0
5.0 10 20
LEAD LENGTH = 1/4″
tp
Ppk
t1
Ppk
DUTY CYCLE = tp/t1
TIME
PEAK POWER, Ppk, is peak of an
equivalent square power pulse.
∆TJL = Ppk • RθJL [D + (1 – D) • r(t1 + tp) + r(tp) – r(t1)] where:
∆TJL = the increase in junction temperature above the lead temperature.
r(t) = normalized value of transient thermal resistance at time, t, i.e.:
r(t1 + tp) = normalized value of transient thermal resistance at time
t1 + tp, etc.
50 100 200
500 1.0 k 2.0 k
5.0 k 10 k 20 k
t, TIME (ms)
Figure 5. Thermal Response
10
7.0
5.0
SINE WAVE
3.0
2.0
1.0
0.7
I(FM)
+ I(AV)
p (Resistive Load)
NJCapacitive
5.0
10
Loads
20
0.5
0.3
0.2
dc
SQUARE WAVE
TJ ≈ 125°C
0.1
0.1
0.2 0.3 0.5 0.7 1.0
2.0 3.0 5.0 7.0 10
IF(AV), AVERAGE FORWARD CURRENT (AMP)
Figure 6. Forward Power Dissipation 1N5820–22
NOTE 3 — APPROXIMATE THERMAL CIRCUIT MODEL
RθS(A) RθL(A) RθJ(A)
TA(A)
TL(A)
TC(A) TJ
RθJ(K) RθL(K) RθS(K)
PD
TC(K)
TA(K)
TL(K)
Use of the above model permits junction to lead thermal resis-
tance for any mounting configuration to be found. For a given total
lead length, lowest values occur when one side of the rectifier is
brought as close as possible to the heat sink. Terms in the model
signify:
TA = Ambient Temperature
TC = Case Temperature
TL = Lead Temperature
TJ = Junction Temperature
RθS = Thermal Resistance, Heat Sink to Ambient
RθL = Thermal Resistance, Lead to Heat Sink
RθJ = Thermal Resistance, Junction to Case
PD = Total Power Dissipation = PF + PR
PF = Forward Power Dissipation
PR = Reverse Power Dissipation
(Subscripts (A) and (K) refer to anode and cathode sides, respec-
tively.) Values for thermal resistance components are:
RθL = 42°C/W/in typically and 48°C/W/in maximum
RθJ = 10°C/W typically and 16°C/W maximum
The maximum lead temperature may be found as follows:
[* n TL = TJ(max)
where TJL
n TJL
RθJL · PD
NOTE 2 — MOUNTING DATA
Data shown for thermal resistance junction–to–ambient (RθJA)
for the mountings shown is to be used as typical guideline values
for preliminary engineering, or in case the tie point temperature
cannot be measured.
TYPICAL VALUES FOR RθJA IN STILL AIR
Mounting
Method
Lead Length, L (in)
1/8 1/4 1/2 3/4
RθJA
1
50 51 53 55 °C/W
2
58 59 61 63 °C/W
3
28
°C/W
Mounting Method 1
Mounting Method 3
P.C. Board where available
P.C. Board with
copper surface is small.
2–1/2″ x 2–1/2″
L
L
ÉÉÉÉÉÉÉÉÉÉÉÉÉÉ ÉÉÉÉÉÉ MountingMethod 2
ÉÉÉÉÉÉÉÉÉÉÉÉ L
L
copper surface.
L = 1/2″
BOARD GROUND
PLANE
VECTOR PUSH–IN
TERMINALS T–28
4
Rectifier Device Data
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