SI-8050S Allegro Microsystems Inc, SI-8050S Datasheet - Page 6

• Manufacturer Part Number: SI-8050S
• Description: IC, LINEAR VOLTAGE REGULATOR 5V TO-220-5
• Manufacturer: Allegro Microsystems Inc

Specifications of SI-8050S

• Primary Input Voltage: 40V
• Output Voltage Fixed: 5V
• No. Of Outputs: 1
• No. Of Pins: 5
• Output Current: 3A
• Operating Temperature Range: -30°C To +125°C
• Power Dissipation Pd: 18W
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

1. Soft Start
2. Output ON/OFF control
(3) Sensing terminal
Connecting a capacitor to terminal no. 5 permits a soft start at power-
on. Delay time T
shown below. (However, the values may slightly vary in an actual
application.) If the capacitance of C
discharge C
set the value within 10 F. When not using the soft start function,
keep terminal no. 5 open.
Output can be turned on and off by using the soft start terminals.
Set the soft start terminal voltage to V
output. To switch the potential at the soft start terminals, drive the
open collector of the transistor. Since the discharge current from C
flows to the ON/OFF control transistor, limit the current for protec-
tion. The SS terminal is pulled up to the power supply in the IC and
no external voltage can be applied.
Output voltage sensing terminal V
to output capacitor C
capacitor, the decreasing regulation and increasing switching
ripple may result in abnormal oscillation.
V
OUT
L
3
T
T
after V
d
s
=
=
V
Top view (with part names)
SI-8000S
IN
Example of basic pattern
5
d
Applications
V
ON/OFF
0.7 C
20 10
4.845 C
SI-8000S
and rise time T
IN
S. S.
IN
+
C
5
C
3
is turned off. Therefore, it is recommended to
20 10
2
S. S.
2
3
–6
as possible. If the terminal is far from the
3
(sec)
–6
D
1
V
V
GND
IN
O
(sec)
s
OS
3
T
1
can roughly be calculated as
is increased, it takes longer to
d
S. S + ON/OFF
SSL
should be connected as close
C
SI-8000S
1
5
T
(0.2V typ.) or less to stop
S
S. S.
5
SI-8000S
C
3
3
3. Variable Output Voltage
The output voltage can be increased by connecting a resistor to V
terminal No. 4. (There is no way of decreasing the voltage)
(1) Variable output voltage with single external resistor
* The temperature characteristics of output voltage worsen because
the value R
fluctuates by up to 20% depending on the IC product. Since the
output voltage fluctuates more, a semi-fixed resistor is necessary
for accurate output voltage adjustment. If Vs and R
the range of output voltage fluctuation can be expressed as follows:
(2) Variable output voltage with two external resistors
The output voltage adjustment resistances R
calculated as follows:
Bypassing the current to R
teristics and voltage fluctuation ranges more than the method of
(1). Stability factor S indicates the ratio of R
inflow current. Increasing the S value improves the fluctuations
of the temperature characteristics and output voltage. (Usually 5
to 10)
If the Vs and R
tion range can be calculated as follows:
The output voltage adjustment resistance R
as follows:
SI-8000S
SI-8000S
EX
V
V
I
VS
S
O
is not compensated for temperature. The Vs value
3
3
' : Adjusted output voltage
: Set output voltage of product
: Inflow current to Vs terminal
R
R
R
S:Stability factor
EX
V
V
V
2
4
EX
2
4
EX
EX
O
O
O
values are constant, the output voltage fluctua-
=
1=
2=
'(%)= 20•
':Adjusted output voltage
'(%)=
V
O
IV
V
'–V
(S-1)•IV
S
O
S•IV
'–V
20
S
V
S
EX2
S
V
S
S
IR
•
O
IV
improves the temperature charac-
L
L
IV
S
'–V
V
EX1
V
S
S
O
O
'
V
S
'–V
O
'
S
SI-8000S Series
V
V
S
R
R
R
S
EX
EX1
EX2
EX1
EX1
C
C
GND
GND
V
EX
EX
2
V
2
O
O
to Vs terminal
and R
'
are constant,
is calculated
EX2
are
85
OS