1N2804 thru 1N2846B and
1N4557 thru 1N4564B
50 Watt Zener Diodes
SCOTTSDALE DIVISION
NOTES:
1.
2.
3.
4.
The JEDEC type numbers shown (B suffix) have a +/- 5% tolerance on nominal zener voltage. The suffix A is used to identify +/-10%
tolerance; no suffix indicates +/-20% tolerance. If tighter tolerance is required, consult factory. Standard polarity units have the anode
connected to the case. Reverse polarity (cathode-to-case) units are available and are indicated by suffix R in the part number.
o
Zener Voltage (V
Z
) is measured with junction in thermal equilibrium with 30 C base temperature. The test currents (I
ZT
) have been selected
o
so that at nominal voltages the dissipation is a constant 12.5 watts. This results in a nominal junction temperature rise of 18.75 C .
The zener impedance is derived from the 60 cycle ac voltage, which results when an ac current having an rms value equal to 10% of the dc
zener current (I
ZT
or I
ZK
) is superimposed on I
ZT
or I
ZK
. Zener impedance is measured at 2 points to ensure a sharp knee on the breakdown
curve and to eliminate unstable units. A curve showing the variation of zener impedance vs. zener current for six representative types is
shown in Figure 3. Also see MicroNote 202 for further information.
The values of I
ZM
are calculated for a +/-5% tolerance on nominal zener voltage. Allowance has been made for the rise in zener voltage
above V
ZT
that results from zener impedance and the increase in junction temperature as power dissipation approaches 50 watts. In the
case of individual diodes, I
ZM
is that value of current that results in a dissipation of 50 watts.
WWW .
Microsemi
.C
OM
GRAPHS AND CIRCUITS
Rated Power Dissipation - Watts
Typical circuit connections for anode-to-case and
cathode-to-case polarities (standard and reverse
polarities, respectively).
Case
Temperature C
o
FIGURE 2
POWER DERATING CURVE
1N2804 - 46B &
1N4557B 鈥?64B
FIGURE GROUP 3
TYPICAL ZENER IMPEDANCE vs. ZENER CURRENT FOR TYPES SHOWN
Copyright
錚?/div>
2003
11-12-2003 REV A
Microsemi
Scottsdale Division
8700 E. Thomas Rd. PO Box 1390, Scottsdale, AZ 85252 USA, (480) 941-6300, Fax: (480) 947-1503
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