Diodes ZXRE330 - Manual (Page 5)

ZXRE330
Document number: DS36772 Rev. 2 - 2
5 of 8
www.diodes.com
January 2014
© Diodes Incorporated
ZXRE330
Start Up Characteristics ZXRE330
I
R
=100μA, No Load Capacitor I
R
=5mA, No Load Capacitor
Application Information
In a conventional shunt regulator application (Figure 1), an external series resistor (R
S
) is connected between the supply voltage, V
S
, and the
ZXRE330.
R
S
determines the current that flows through the load (I
L
) and the ZXRE330 (I
R
). Since load current and supply voltage
may vary, R
S
should be small enough to supply at least the minimum acceptable I
R
to the ZXRE330 even when the
supply voltage is at its minimum and the load current is at its maximum value. When the supply voltage is at its maximum
and I
L
is at its minimum, R
S
should be large enough so that the current flowing through the ZXRE330 is less than 10 mA.
R
S
is determined by the supply voltage, (V
S
), the load and operating current, (I
L
and I
R
), and the ZXRE330’s reverse
breakdown voltage, V
R
.
R L
R S
S
I I
V V
R



Printed circuit board layout considerations
ZXRE330 in the SOT23 package have the die attached to pin 1, which results in an electrical contact between pin 2 and
pin 3. Therefore, pin 1 of the SOT23 package must be left floating or connected to pin 2.
ZXRE330 in the TO92 package have the die attached to pin 2, which results in an electrical contact between pin 2 and pin
1. Therefore, pin 2 must be left floating or connected to pin1.
R
S
V
S
I
R
+
I
L
I
R
I
L
V
R
Input
Output
Input
Output