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ST1S09PUR

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18
Typical performance characteristics ST1S09
10/18 Doc ID 13632 Rev 4
Figure 15. Efficiency vs. temperature Figure 16. Over voltage protection vs.
temperature
Figure 17. Over voltage protection vs.
temperature
Figure 18. Over voltage protection hyst. vs.
temperature
Figure 19. Load transient Figure 20. Inhibit transient
V
I
= 5 V, V
O
= 1.2 V, I
O
= 100 mA to1 A, L = 3.3 µH,
C
I
= 4.7 µF, C
O
= 22 µF
V
I
= 5V, V
INH
= 0 to 2 V, I
O
= 2 A, L = 3.3 µH, C
I
= 4.7 µF,
C
O
= 22 µF, V
O
= 3.3 V
40
45
50
55
60
65
70
75
80
85
90
95
100
-75 -50 -25 0 25 50 75 100 125 150 175
T [°C]
Efficiency [%]
V
O
=1.2V
V
O
=3.3V
V
I
=5V, I
O
=100mA
40
45
50
55
60
65
70
75
80
85
90
95
100
-75 -50 -25 0 25 50 75 100 125 150 175
T [°C]
Efficiency [%]
V
O
=1.2V
V
O
=3.3V
V
I
=5V, I
O
=100mA
V
SW
=1.2V
0.8
0.9
1
1.1
1.2
1.3
1.4
-75 -50 -25 0 25 50 75 100 125 150 175
T [°C]
OVP %V
O
OVP ON
V
I
=5V, V
O
=3.3V, C
FB
=100nF
Resistor 1.2kΩ from V
I
and V
SW
V
SW
=1.2V
0.8
0.9
1
1.1
1.2
1.3
1.4
-75 -50 -25 0 25 50 75 100 125 150 175
T [°C]
OVP %V
O
OVP ON
V
I
=5V, V
O
=3.3V, C
FB
=100nF
Resistor 1.2kΩ from V
I
and V
SW
0.8
0.9
1
1.1
1.2
1.3
1.4
-75 -50 -25 0 25 50 75 100 125 150 175
T [°C]
OVP %V
O
V
SW
=0.8V V
I
=5V, V
O
=3.3V, C
FB
=100nF
Resistor 1.2kΩ from V
I
and V
SW
OVP ON
0.8
0.9
1
1.1
1.2
1.3
1.4
-75 -50 -25 0 25 50 75 100 125 150 175
T [°C]
OVP %V
O
V
SW
=0.8V V
I
=5V, V
O
=3.3V, C
FB
=100nF
Resistor 1.2kΩ from V
I
and V
SW
OVP ON
0
2
4
6
8
10
12
14
-75 -50 -25 0 25 50 75 100 125 150 175
T [°C]
OVP % Hysteresis
V
SW
=0.8V V
I
=5V, V
O
=3.3V, C
FB
=100nF
Resistor 1.2kΩ from V
I
and V
SW
OVP ON
0
2
4
6
8
10
12
14
-75 -50 -25 0 25 50 75 100 125 150 175
T [°C]
OVP % Hysteresis
V
SW
=0.8V V
I
=5V, V
O
=3.3V, C
FB
=100nF
Resistor 1.2kΩ from V
I
and V
SW
OVP ON
V
O
I
O
V
O
I
O
V
INH
V
O
I
O
V
INH
V
O
I
O
ST1S09 Typical application
Doc ID 13632 Rev 4 11/18
6 Typical application
Figure 21. Application circuits
Figure 22. Application circuits
Application information ST1S09
12/18 Doc ID 13632 Rev 4
7 Application information
The ST1S09 is an adjustable current mode PWM step-down DC-DC converter with internal
2 A power switch, packaged in a DFN6 3 x 3 mm.
The device is a complete 2 A switching regulator with its internal compensation eliminating
the need for additional components.
The constant frequency, current mode, PWM architecture and stable operation with ceramic
capacitors results in low, predictable output ripple.
The over-voltage protection circuit acts when the output voltage is over 10 % of the rated
voltage and within 200 ns the low side MOSFET will be turned on to clamp the output
transient. The current limit for clamping is about 400 mA. When the output voltage drops to
about 5 % above the nominal level, the device returns to nominal closed loop switching
operation.
The open drain Power Good (PG) pin is released when the output voltage is higher than
0.92 x V
O_NOM
. If the output voltage is below 0.92 x V
O
, the PG pin goes to low impedance.
Other circuits fitted to the device protection are the thermal shut-down block, which turns off
the regulator when the junction temperature exceeds 150 °C (typ), and the cycle-by-cycle
current limiting, which provides protection against shorted outputs.
As an adjustable regulator, the ST1S09’s output voltage is determined by an external
resistor divider. The desired value is given by the following equation:
Equation 1
V
O
= V
FB
[1 + R
1
/ R
2
]
To utilize the device, only a few components are required: an inductor, two capacitors and
the resistor divider. The inductor chosen must be able to reach peak current level without
saturating. Its value can be selected while taking into account that a large inductor value
increases the efficiency at low output current and reduces output voltage ripple, while a
smaller inductor can be chosen when it is important to reduce package size and the total
cost of the application. Finally, the ST1S09 has been designed to work properly with X5R or
X7R SMD ceramic capacitors both at the input and at the output. These types of capacitors,
due to their very low series resistance (ESR), minimize the output voltage ripple. Other low
ESR capacitors can be used according to the need of the application without compromising
the correct functioning of the device.
P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18

ST1S09PUR

Mfr. #:
Buy ST1S09PUR
Manufacturer:
STMicroelectronics
Description:
Switching Voltage Regulators 2A 1.5 MHz PWM Step Down Switch Reg
Lifecycle:
New from this manufacturer.
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