SI-3201S Datasheet, PDF (1/2 Pages) Sanken electric – Switching Type Regulator

Switching Type Regulator SI-3201S
Features
q Output current of 3A (Ta = 25ºC, VIN = 8 to 18V)
q High efficiency of 82% (VIN = 14V, IO = 2A)
q Requires 5 external components only
q Built-in reference oscillator (60kHz)
q Phase internally corrected
q Output voltage internally corrected
q Built-in overcurrent and thermal protection circuits
q Built-in soft start circuit
External Dimensions (unit: mm)
3.2 ^±0.2
10.0 ^±0.2
4.2 ^±0.2
2.8 ^±0.2
a
b
2.6 ^±0.1
Absolute Maximum Ratings
Parameter
Symbol
Input voltage
Output voltage
SQ terminal voltage with respect
to ground
VIN
IO
VO, SQ
Power Dissipation
Junction temperature
Storage temperature
Junction to case thermal resistance
Junction to ambient-air thermal
resistance
PD1
PD2
Tj
Tstg
j-c
j-a
Ratings
35
3
–1
22
1.8
–40 to +150
–40 to +125
5.5
66.7
Unit
V
A
V
W
W
ºC
ºC
ºC/W
ºC/W
(Ta=25ºC)
Conditions
With infinite heatsink
Stand-alone
Recommended Operating Conditions
Parameter
Input voltage
Output current
Operating temperature
Symbol
Ratings
min
typ
max
VIN
8
18
IO
0.5
3
Top
–40
+85
Unit
Conditions
V
A
ºC
Ta—PD characteristics
Electrical Characteristics _{(VIN = 14V, IOUT = 2A, Tj = 25ºC unless otherwise specified)}
Parameter
Ratings
Symbol
Unit
min
typ
max
Conditions
Output voltage
VO
4.80
5.00
5.20
V
Line regulation
VO LINE
100
mV
VIN = 8 to 18V
Load regulation
Efficiency *¹
VO LOAD
50
mV
IO = 0.5 to 3A
82
%
Oscillation frequency
fOSC
50
60
70
kHz
Quiescent circuit current
Iq
5
10
mA
IO = 0A
Overcurrent protection starting
IS
3.1
current
A
*²
Soft *^{3 Low level voltage}
VSSL
0.2
V
start
Source current when low
I SSL
15
25
35
µA
VSSL = 0.2V
terminal _{Discharge resistance}
RDIS
4
kΩ
Notes:
*1. Efficiency is calculated by the following equation:
=
VO • IO
VIN • IIN
• 100 (%)
*2. A drooping-type overcurrent protection circuit is built in the IC.
*3. An external voltage may not be applied to the soft start terminal. As shown in the diagram to the
right, use this IC in the soft start mode with a capacitor or in the open-collector drive mode with a
transistor. Leave the soft start terminal open when not using it since it is already pulled up in the IC.
0.95 ^±0.15
+0.2
0.85 –0.1
P1.7±0.7 •4 = 6.8 ±0.7
+0.2
0.45^–0.1
3.9 ^±0.7 (4.3)
8.2 ^±0.7
12345
1. VIN
2. SWOUT
3. GND
4. VOS
5. SS
a: Type No.
b: Lot No.
(Forming No. 1101)
Standard Circuit Diagram
VIN
+
C1
C3
GND
1
SI-3201S SW Tr 2
L1
VIN
a
b
CQ
VO
c
d
e
f
5 SS
g
h
GND ⁱ
3
D1
VS 4
+
C2
GND
C1: 1000µF
C2: 1000µF
a: Internal power supply
b: Thermal protection
c: Reference oscillator
d: Reset
e: Latch & driver
L1: 250µH
D1: RK46 (Sanken)
f : Comparator
g: Overcurrent protection
h: Error amplifier
i : Reference voltage
Cautions:
(1) A high-ripple current flows through C1 and C2. Use high-ripple
type 1000µF or higher capacitors with low internal resistance.
Refer to the respective data books for more information on
reliability and electrical characteristics of the capacitor.
(2) C3 is a capacitor used for soft start.
(3) L1 should be a choke coil with a low core loss for switching
power supplies.
(4) Use a Schottky barrier diode for D1 and make sure that the
reverse voltage applied to the 2nd terminal (SQ terminal) is
within the maximum ratings (–1V). If you use a fast-recovery
diode, the recovery voltage and the ON forward voltage may
cause a reversed-bias voltage exceeding the maximum ratings
to be applied to the 2nd terminal (SQ terminal). Applying a
reversed-bias voltage exceeding the maximum rating to the
2nd terminal (SQ terminal) may damage the IC.
(5) The 4th terminal (VS) is an output voltage detection terminal.
Since this terminal has a high impedance, connect it to the
positive (+) terminal of C2 via the shortest possible route.
(6) Leave the 5th terminal (soft start terminal) open when not
using it. It is pulled up internally.
(7) To ensure optimum operating environment, connect the high-
frequency current line with minimum wiring length.
SI-3201S
5 SS
C3
SI-3201S
5 SS
SI-3201S
5 SS
C3
18