SANKEN STA820M

1-1-2 Switching Mode Regulator ICs
STA820M Series Separate Excitation Switching Mode Regulator ICs with Flywheel Diode
■Features
■Lineup
• Output current: 3A
• High efficiency: TYP 83% (STA821M)
Part Number
Output Voltage (V)
STA821M
5
Output voltage: 3.3V, 9V, 12V; adjustable types currently being planned
• Built-in flywheel diode (Schottky-barrier diode)
• Requires only 3 discrete components: output
coil, input and output capacitors
■Absolute Maximum Ratings*1
• Phase correction and output voltage
adjustment performed internally
Parameter
• Built-in reference oscillator (110kHz)
Symbol
Ratings
Unit
DC Input Voltage
VIN
31
V
Output Current
IO
3
A
PD1
18.2 (With infinite heatsink)
W
• Built-in foldback-overcurrent and thermal
protection circuits
Power
PD2
2.7 (Without heatsink, stand-alone operation)
W
• Built-in ON/OFF circuit (soft start available)
Junction Temperature
Tj
+125
°C
Storage Temperature
Tstg
–40 to +125
°C
Thermal Resistance (Junction to Case)
θ j-c
5.5
°C/W
Thermal Resistance (Junction to Ambient Air)
θ j-a
37
°C/W
■Applications
• Power supplies for telecommunication
equipment
Dissipation*2
*1: The absolute maximum ratings show the destructive limit. No parameter should exceed the ratings in transient or
normal operations.
*2: Limited by thermal protection.
• On-board local power supplies
• OA equipment
• For stabilization of the secondary-side output
voltage of switching power supplies
■Recommended Operating Conditions*1
Ratings
Parameter
Symbol
STA821M
Unit
min.
max.
DC Input Voltage Range
VIN
7
30
Output Current Range*2
IO
0
3
V
A
Operating Junction Temperature Range
Tjop
–30
+125
°C
Ambient Temperature Range*2
Top
–30
+80
°C
*1: The recommended operating conditions show the operating conditions required for the normal circuit function described in the electrical characteristics. These conditions must be
followed in actual use.
*2: Limited by Ta-PD characteristics.
■Electrical Characteristics
(Ta=25°C)
Ratings
Parameter
Symbol
STA821M
min.
VO
Output Voltage
4.8
Conditions
Terminal*2
Conditions
40
VSSL
Outflow Current
at Low Voltage
ISSL
Quiescent Circuit Current
100
mV
10
40
mV
VIN=20V, IO=0.5 to 1.5A
±0.5
mV/ °C
3.1
Conditions
Low Level Voltage
kHz
VIN=10 to 30V, IO=1A
∆VO/∆T
IS
%
VIN=20V, IO=1A
VLoad
Overcurrent Protection Starting
Current
V
110
Conditions
Temperature Coefficient of Output Voltage
ON/OFF
fO
Conditions
Load Regulation
5.2
VIN=20V, IO=1A
VLine
Line Regulation
5.0
83
Conditions
Oscillation Frequency
max.
VIN=20V, IO=1A
η
Efficiency*1
Unit
typ.
A
VIN=20V
0.2
15
Conditions
Iq
Conditions
V
25
35
µA
VSSL=0.2V
4
mA
VIN=20V, IO=0A
*1: Efficiency is calculated from the following formula.
η(%) =
VO·IO
VIN·IIN
× 100
*2: Pin 7 is the ON/OFF pin. Soft start at power on can be performed by connecting a
capacitor to this pin. The output can also be turned ON/OFF with this pin. The output is
stopped by setting the voltage of this pin to VSSL or lower. ON/OFF-pin voltage can be
changed with an open-collector drive circuit of a transistor. When using both the soft-start
and ON/OFF functions together, the discharge current from C3 flows into the ON/OFF
control transistor. Therefore, limit the current securely to protect the transistor if C3
capacitance is large. The ON/OFF pin is pulled up to the power supply in the IC, so
applying the external voltage is prohibited. If this pin is not used, leave it open.
STA821M
STA821M
STA821M
7 ON/OFF
7 ON/OFF
7 ON/OFF
C3
VO. ON/OFF
88
ICs
Soft start
C3
Soft start
+VO. ON/OFF
STA820M Series
■External Dimensions (SIP8 [STA 8Pin])
(Unit : mm)
4±0.2
STA821M
a
1.2±0.1
(Measured at
the root)
(1)
3.15±0.5
9±0.2
1.7MAX
2.3±0.2
b
SK
Pin Assignment
q SWOUT
w GND
e VIN
r N.C
t GND
y VOS
u ON/OFF
i GND
2–(R1)
2–(R
0.65
)
R-END
(3.1)
1.15+0.2
–0.1
7×P2.54±0.1=(17.78)
(Measured at the root)
C1.5±0.5
0.55+0.2
–0.1
4.3±0.7
(Measured at
the tip)
20.15±0.3
0.7
1
2
3
4
5
6
7
Plastic Mold Package Type
Flammability: UL 94V-0
Product Mass: Approx. 2.0 g
0.7
Plan View
8
■Block Diagram
STA821M
VIN
C1
3
SW
OUT
VIN
+
1
L
VOUT
+
Internal
Power Supply
Overcurrent
Protection
Di
Latch &
Driver
Reset
C2
GND
2
Oscillator
7
+
–
ON/OFF
Comparator
Error Amplifier
VOS
Thermal
Protection
6
+
–
Reference
Voltage
GND
5,8
■Ta-PD Characteristics
■Typical Connection Diagram
20
3.VIN
STA821M
+
7.ON/OFF
C1
6.VOS
2.GND
5,8.GND
+
C2
C3
GND
GND
C1
C2
C3
L1
1000µF/50V
: 1000µF/25V
: 0.47µF/10V(only when the soft start function is used)
: 100µH
:
18
VOUT
Power Dissipation PD (W)
VIN
Without Insulating Sheet
With Silicone Grease
Heatsink: Aluminum
With Infinite Heatsink
L1
1.SW
16
14
12
10
PD = VO·IO
100×100×2mm (11.5°C/W)
100
–1
ηχ
8
6 50×50×2mm (17.9°C/W)
VO : Output voltage
4
25×50×2mm
(25°C/W)
2
IO
Without Heatsink (37°C/W)
0
–25
0
25
50
VIN : Input voltage
75
100
125
: Output
current
ηχ : Efficiency (%)
Ambient Temperature Ta (°C)
ICs
89