STA820M Datasheet, PDF (1/2 Pages) Sanken electric – Separate Excitation Switching Mode Regulator ICs with Flywheel Diode

1-1-2 Switching Mode Regulator ICs
STA820M Series Separate Excitation Switching Mode Regulator ICs with Flywheel Diode
■Features
• Output current: 3A
• High efficiency: TYP 83% (STA821M)
• Built-in flywheel diode (Schottky-barrier diode)
• Requires only 3 discrete components: output
coil, input and output capacitors
• Phase correction and output voltage
adjustment performed internally
• Built-in reference oscillator (110kHz)
• Built-in foldback-overcurrent and thermal
protection circuits
• Built-in ON/OFF circuit (soft start available)
■Applications
• Power supplies for telecommunication
equipment
• On-board local power supplies
• OA equipment
• For stabilization of the secondary-side output
voltage of switching power supplies
■Lineup
Part Number
STA821M
Output Voltage (V)
5
Output voltage: 3.3V, 9V, 12V; adjustable types currently being planned
■Absolute Maximum Ratings^*1
Parameter
DC Input Voltage
Output Current
Power Dissipation^*2
Junction Temperature
Storage Temperature
Thermal Resistance (Junction to Case)
Thermal Resistance (Junction to Ambient Air)
Symbol
VIN
IO
PD1
PD2
Tj
Tstg
θ j-c
θ j-a
Ratings
31
3
18.2 (With infinite heatsink)
2.7 (Without heatsink, stand-alone operation)
+125
–40 to +125
5.5
37
Unit
V
A
W
W
°C
°C
°C/W
°C/W
*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.
■Recommended Operating Conditions^*1
Ratings
Parameter
Symbol
STA821M
Unit
min.
max.
DC Input Voltage Range
VIN
7
30
V
Output Current Range^*2
IO
0
3
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
Parameter
Symbol
min.
Output Voltage
VO
4.8
Conditions
Efficiency^*1
η
Conditions
Oscillation Frequency
fO
Conditions
Line Regulation
VLine
Conditions
Load Regulation
VLoad
Conditions
Temperature Coefficient of Output Voltage
∆VO/∆T
Overcurrent Protection Starting
IS
3.1
Current
Conditions
Low Level Voltage
VSSL
ON/OFF
Terminal^*2
Outflow Current
at Low Voltage
ISSL
Conditions
15
Quiescent Circuit Current
Iq
Conditions
*1: Efficiency is calculated from the following formula.
VO·IO
η(%) =
× 100
VIN·IIN
*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.
Ratings
STA821M
typ.
5.0
VIN=20V, IO=1A
83
VIN=20V, IO=1A
110
VIN=20V, IO=1A
40
VIN=10 to 30V, IO=1A
10
VIN=20V, IO=0.5 to 1.5A
±0.5
VIN=20V
0.2
25
VSSL=0.2V
4
VIN=20V, IO=0A
STA821M
7 ON/OFF
VO. ON/OFF
max.
5.2
100
40
35
(Ta=25°C)
Unit
V
%
kHz
mV
mV
mV/ °C
A
V
µA
mA
STA821M
7 ON/OFF
C3
Soft start
STA821M
7 ON/OFF
C3
Soft start
+VO. ON/OFF
88 ICs