ST1S03
1.5 A, 1.5 MHz adjustable,
step-down switching regulator
Features
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Step-down current mode PWM (1.5 MHz)
DC-DC converter
2 % DC output voltage tolerance
Internal soft start for START-UP current
limitation and power on delay of 50-100 µs
Typical efficiency: > 70 % over all operating
conditions
1.5 A output current capability
Not switching quiescent current: max 2.5 mA
over temperature range
Switch V
DS
: max 350 mV @ I
SW
= 750 mA
Uses tiny capacitors and inductors
Available in DFN 3x3 mm exposed pad
over an input voltage range of 3 V to 16 V. An high
switching frequency (1.5 MHz) allows the use of
tiny surface-mount components: as well as the
resistor divider to set the output voltage value,
only an inductor, a schottky diode and two
capacitors are required. Besides, a low output
ripple is guaranteed by the current mode PWM
topology and by the use of low ESR SMD ceramic
capacitors. The device is thermal protected and
current limited to prevent damages due to
accidental short circuit. The ST1S03 is available
in DFN6.
DFN6D (3x3mm)
Description
The ST1S03 is a step down DC-DC converter
optimized for powering low-voltage digital core in
HDD applications and, generally, to replace the
high current linear solution when the power
dissipation may cause an high heating of the
application environment. It provides up to 1.5 A
Table 1.
Device summary
Order code
ST1S03PU
Packaging
ST1S03PUR
Package
DFN6D (3x3 mm)
March 2008
Rev 6
1/16
www.st.com
16
Contents
ST1S03
Contents
1
2
3
4
5
6
7
8
9
Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Application notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Typical application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Typical performance characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
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ST1S03
Maximum ratings
3
Table 3.
Maximum ratings
Absolute maximum ratings
Parameter
Positive power supply voltage
Positive power supply voltage
Max voltage of output pin
Feedback voltage
Common mode input voltage
Max junction temperature
Storage temperature range
Lead temperature (Soldering) 10 Sec.
Value
-0.3 to 16
-0.3 to 16
-0.3 to 16
2.5
±1
150
-25 to 150
300
Unit
V
V
V
V
mA
°C
°C
°C
Symbol
V
IN_SW
V
IN_A
SWITCH voltage
V
FB
I
VFB
T
J
T
STG
T
LEAD
Note:
Absolute maximum ratings are those values beyond which damage to the device may occur.
Functional operation under these conditions is not implied.
Thermal data
Parameter
Thermal resistance junction-case
Thermal resistance junction-ambient
Value
10
55
Unit
°C/W
°C/W
Table 4.
Symbol
R
thJC
R
thJA
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