
No. 5969-6/7
LA5633
EN (on/off control) Input Block Equivalent Circuit Block Diagram
Usage Notes
GND1 and GND2 are connected through the IC substrate, and must be connected to the lowest potential in the system
and must be connected to identical potentials.
(The functions and characteristics of this IC are not guaranteed if GND1 and GND2 are connected to different potentials.)
The rise and fall of the V
IN
1, V
IN
2, and V
IN
3 voltages must be simultaneous, and none of these pins may be either left
open or connected to ground.
If either V
IN
1 or V
IN
2 are open or at a voltage lower than the stipulated voltage, then the V
O
1 through V
O
4 outputs
will be forcibly turned off to protect the IC.
The output capacitors C
O
1 and C
O
4 must be at least 100 μF, and C
O
2 and C
O
3 must be at least 47 μF. Capacitors with
low temperature coefficients must be use to prevent oscillation at low temperatures.
To assure stable operation, the input capacitors C
IN
1 to C
IN
3 and the output capacitors C
O
1 to C
O
4 must be placed as
close to the IC as possible.
The NC pins (pins 1 and 14) must not be used.
The output voltage V
O
4 can be adjusted by connecting resistors from the CN pin (pin 11) to either V
O
4 or to GND2.
— To lower V
O
4: Add resistor RA between CN and V
O
4.
— To raise V
O
4: Add resistor RB between CN and GND2.
Also note that external noise suppression and ripple rejection can be improved by adding an external capacitor at
V
O
4. However, care is required to assure that the system stability (phase margin) is adequate.
Note that these power supplies can be influenced by load fluctuations in the other power supplies.
Sample CN Pin Application Circuit
Control signal
≈
Control signal
Control
signal
Control
signal
≈