1-1-2 Switching Mode Regulator ICs
STA810M Series
Separate Excitation Switching Mode Regulator ICs with Flywheel Diode
sFeatures
•
•
•
•
•
•
•
•
Output current: 1.5A
High efficiency: TYP83% (STA811M)
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 (125kHz)
Built-in foldback-overcurrent and thermal
protection circuits
Built-in ON/OFF circuit (soft start available)
sLineup
Part Number
STA811M
Output Voltage (V)
6.5
Output voltage: 2.5V, 3.3V, 5V, 9V, 12V and adjustable types are projected.
sAbsolute
Maximum Ratings
*1
Parameter
DC Input Voltage
Output Current
Power Dissipation
*2
Junction Temperature
Symbol
V
IN
I
O
P
D1
P
D2
T
j
T
stg
Ratings
43
1.5
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
sApplications
• Power supplies for telecommunication
equipment
• Onboard local power supplies
• OA equipment
• For stabilization of the secondary-side output
voltage of switching power supplies
Storage Temperature
Thermal Resistance (junction to case)
Thermal Resistance (junction to ambient air)
θ
j-c
θ
j-a
*1: Absolute maximum ratings show the destructive limit. No parameter should exceed the ratings in transient or normal
operations.
*2: Limited by thermal protection.
sRecommended
Operating Conditions
*1
Ratings
Parameter
Symbol
min.
DC Input Voltage Range
Output Current Range
*2
Operating Junction Temperature Range
Operating Temperature Range
*2
V
IN1
V
IN2
I
O
T
jop
T
op
8.5
9.5
0
–30
–30
STA811M
max.
9.5
40
1.5
+125
+80
V
V
A
°C
°C
I
O
=0 to 1A
I
O
=0 to 1.5A
V
IN
≥
9.5V
Unit
Conditions
*1: Recommended operating conditions show operating conditions required for normal circuit function described in the electrical characteristics.
These conditions must be followed in actual use.
*2: Limited by T
a
-P
D
characteristics.
sElectrical
Characteristics
Ratings
Parameter
Symbol
min.
Output Voltage
Efficiency
*1
Oscillation Frequency
Line Regulation
Load Regulation
Temperature Coefficient of Output Voltage
Overcurrent Protection
Starting Current
Low Level Voltage
ON/OFF
Terminal
*2
Outflow Current
at Low Voltage
V
O
Conditions
6.37
STA811M
typ.
6.5
V
IN
=28V, I
O
=1A
83
V
IN
=28V, I
O
=1A
125
V
IN
=28V, I
O
=1A
40
V
IN
=10 to 30V, I
O
=1A
10
V
IN
=28V, I
O
=0.2 to 1A
±0.5
1.6
V
IN
=28V
0.5
100
V
SSL
=0V
7
V
IN
=28V, I
O
=0A
200
V
IN
=28V, V
ON/OFF
=0.3A
40
100
max.
6.63
(T
a
=25°C)
Unit
V
%
kHz
mV
mV
mV/
°C
A
V
η
Conditions
f
O
Conditions
V
Line
Conditions
V
Load
Conditions
∆V
O
/∆T
I
S
Conditions
V
SSL
I
SSL
Conditions
I
q
Conditions
I
q(OFF)
Conditions
µ
A
mA
Quiescent Circuit
Current 1
Quiescent Circuit
Current 2
µ
A
*1: Efficiency is calculated from the following formula.
η
(%) = V
O
·I
O
×
100
V
IN
·I
IN
*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 V
SSL
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 C
3
flows into the ON/OFF
control transistor. Therefore, limit the current securely to protect the transistor if C
3
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.
STA811M
STA811M
STA811M
7 ON/OFF
7 ON/OFF
C
3
7 ON/OFF
C
3
V
O.
ON/OFF
Soft start
Soft start
+V
O.
ON/OFF
76
ICs