PQ7DV5 Datasheet, PDF (4/4 Pages) Sharp Electrionic Components – Variable Output Type, High Output Current (5A) Type Low Power-loss Voltage Regulators

Low Power-Loss Voltage Regulators
Fig.11 Ripple Rejection vs. Junction
Temperature
100
80
60
40
VIN=5V
20 VO=3V(R1=2kΩ,R2=2.8kΩ)
IO =0.5A,ei=0.5Vrms
f=120Hz
0
-25 0 25 50 75 100 125
Junction temperature Tj (˚C)
PQ7DV5
s Standard Connection
D1
VIN
1q
2q
VO
+
R2
5q
4q 3q
Cref
+
CIN
R1 _2kΩ
CO
ON/OFF
signal
High or Open :Output ON
Low
:Output OFF
D1 : This device is necessary to protect the element from damage when reverse voltage may be applied to the regulator in case of
input short-circuiting.
Cref : This device is necessary when it is required to enhance the ripple rejection or to delay the output start-up time*. Otherwise, it
is not necessary.
(Care must be taken since Cref may raise the gain, facilitating oscillation.)
* The output start-up time proportional to Cref X R2.
CIN, CO : Be sure to mount the devices CIN and CO as close to the device terminal as possible so as to prevent oscillation.
The standard specification of CIN= 0.33µF ,CO= 47µF, respectively. However, adjust them as necessary after checking.
R1, R2 : These devices are necessary to set the output voltage. The output voltage VO is given by the following formula:
VO=Vref X (1+R2/R1)
(Vref is 1.25V TYP)
The standard value of R1 is 2Ω. But value up to 10kΩ.