ST1S06xx
Synchronous rectification with inhibit, 1.5 A, 1.5 MHz fixed or
adjustable, step-down switching regulator
Features
■
Step-down current mode PWM (1.5 MHz) DCDC converter
■
2% DC output voltage tolerance
■
Synchronous rectification
■
Inhibit function
■
Internal soft start
■
Typical efficiency: > 90 %
■
1.5 A output current capability
■
Not switching quiescent current: max 1.5 mA
over temperature range
■
RDS(ON) typ.150 mΩ
■
Uses tiny capacitors and inductors
■
Operative junction temp. - 30 °C to 125 °C
■
Available in DFN6D (3x3 mm) exposed pad
DFN6D (3x3 mm)
Description
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
ST1S06xx is available in DFN6D (3x3 mm)
package.
The ST1S06xx 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
over an input voltage range of 2.7 V to 6 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 and two capacitors are required.
Table 1.
Device summary
Part numbers
Marking
Order codes
Package
ST1S06
ST1S06
ST1S06PUR
DFN6D (3 x 3 mm)
ST1S06A
ST1S06A
ST1S06APUR
DFN6D (3 x 3 mm)
ST1S06XX12
1S0612
ST1S06PU12R
DFN6D (3 x 3 mm)
ST1S06XX33
1S0633
ST1S06PU33R
DFN6D (3 x 3 mm)
May 2009
Doc ID 12236 Rev 9
1/20
www.st.com
20
Contents
ST1S06xx
Contents
1
Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2
Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3
Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4
Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5
Typical performance characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6
Typical application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
7
Application notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
8
Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
9
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
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ST1S06xx
Diagram
1
Diagram
Figure 1.
Schematic diagram
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Pin configuration
ST1S06xx
2
Pin configuration
Figure 2.
Pin configuration (top view)
ST1S06A
ST1S06
* Pin 1 is VFB for ADJ version and VO for Fixed version
Table 2.
Pin description
Pin n°
Symbol
Note
1
FB/VO
Feedback voltage / output voltage
2
GND
System ground
3
SW
4
VIN_SW
5
VIN_A
Power supply for analogic circuit
6
VINH
Inhibit pin to turn off the device
Switching pin
Power supply for the mosfet switch
Exposed pad to be connected to GND
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Doc ID 12236 Rev 9
ST1S06xx
Maximum ratings
3
Maximum ratings
Table 3.
Absolute maximum ratings
Symbol
Parameter
Value
Unit
VIN_SW
Positive power supply voltage
-0.3 to 7
V
VIN_A
Positive power supply voltage
-0.3 to 7
V
VINH
Inhibit voltage
-0.3 to VI + 0.3
V
-0.3 to 7
V
-0.3 to 2.5
V
-0.3 to 6
V
SWITCH
voltage
VFB/VO
Max. voltage of output pin
Feedback voltage
VO
Output voltage (for VO > 1.6 V)
TJ
Max junction temperature
-40 to 150
°C
TSTG
Storage temperature range
-65 to 150
°C
TLEAD
Lead temperature (soldering) 10 sec
260
°C
Note:
Absolute maximum ratings are those values beyond which damage to the device may occur.
Functional operation under these conditions is not implied.
Table 4.
Thermal data
Symbol
Parameter
Value
Unit
RthJA
Thermal resistance junction-ambient
55
°C/W
RthJC
Thermal resistance junction-case
10
°C/W
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Electrical characteristics
4
ST1S06xx
Electrical characteristics
VIN_SW = VIN_A = VINH = 5 V, VO = 1.2 V, CI = 4.7 µF, CO = 22 µF, L1 = 3.3 µH, TJ = -30 °C to
125 °C unless otherwise specified. Typical values are referred to TJ = 25 °C.
Table 5.
Electrical characteristics for ST1S06
Symbol
Parameter
FB
Feedback voltage
IFB
VFB pin bias current
VI
Minimum input voltage
IQ
Quiescent current
IO
Output current
Test conditions
IO = 10mA to 1.5A
Min.
Typ.
Max.
Unit
784
800
816
mV
600
nA
2.7
V
VINH > 1.2V
VINH < 0.4V, TJ = -30°C to 85°C
VINH
Inhibit threshold
VI = 2.7 to 5.5V Note 1
1.5
Device ON, VI = 2.7 to 5.5V
1.3
Device ON, VI = 2.7 to 5V
1.2
mA
1
µA
A
V
Device OFF
IINH
1.5
0.4
Inhibit pin current
2
µA
%VO/ΔVI
Reference line regulation
VI = 2.7V to 5.5V Note 1
0.2
0.3
%VO/
ΔVI
%VO/ΔIO
Reference load regulation
IO = 10mA to 1.5A Note 1
0.2
0.3
%VO/
ΔIO
PWMfS
PWM switching frequency
VFB = 0.8V
1.2
1.5
1.8
MHz
80
87
%
DMAX
Maximum duty cycle
RDSON-N
NMOS switch on resistance
ISW = 750 mA
0.12
Ω
RDSON-P
PMOS switch on resistance
ISW = 750 mA
0.15
Ω
ISWL
Switching current limitation
Note 1
2.3
A
ν
Efficiency Note 1
TSHDN
IO = 10mA to 100mA, VO = 3.3V
65
IO = 100mA to 1.5A, VO = 3.3V
85
90
130
150
°C
15
°C
Thermal shutdown
%
Thermal shutdown hysteresis
THYS
%VO/ΔIO
Load transient response
IO = 100mA to 750mA, TJ =
25°C tR = tF ≥ 200ns, Note 1
-5
+5
%VO
%VO/ΔIO
Short circuit removal response
IO = 10mA to IO = short,
TJ = 25°C Note 1
-10
+10
%VO
Note:
6/20
1
Guaranteed by design, but not tested in production
Doc ID 12236 Rev 9
ST1S06xx
Electrical characteristics
VIN_SW = VIN_A = VINH = 5 V, VO = 1.2 V, CI = 4.7 µF, CO = 22 µF, L1 = 3.3 µH, TJ = -30 °C to
125 °C unless otherwise specified. Typical values are referred to TJ = 25 °C.
Table 6.
Electrical characteristics for ST1S06PM12
Symbol
OUT
Parameter
Test conditions
Output feedback pin
IO
IO pin bias current
VO = 1.5V
VI
Minimum input voltage
IO = 10mA to 1.5A
IQ
Quiescent current
IO
Output current
Min.
Typ.
Max.
Unit
1.176
1.2
1.224
V
15
20
µA
2.7
V
VINH > 1.2V
VINH < 0.4V, TJ = -30°C to 85°C
VINH
Inhibit threshold
VI = 2.7 to 5.5V Note 1
1.5
Device ON, VI = 2.7 to 5.5V
1.3
Device ON, VI = 2.7 to 5V
1.2
mA
1
µA
A
V
Device OFF
IINH
1.5
0.4
Inhibit pin current
2
µA
%VO/ΔVI
Reference line regulation
VI = 2.7V to 5.5V Note 1
0.2
0.3
%VO/
ΔVI
%VO/ΔIO
Reference load regulation
IO = 10mA to 1.5A Note 1
0.2
0.3
%VO/
ΔIO
PWMfS
PWM switching frequency
VFB = 0.8V
1.2
1.5
1.8
MHz
80
87
%
Maximum duty cycle
DMAX
RDSON-N
NMOS switch on resistance
ISW = 750 mA
0.12
Ω
RDSON-P
PMOS switch on resistance
ISW = 750 mA
0.15
Ω
ISWL
Switching current limitation
Note 1
2.3
A
ν
Efficiency Note 1
TSHDN
IO = 10mA to 100mA, VO = 1.2V
60
IO = 100mA to 1.5A, VO = 1.2V
80
85
130
150
°C
15
°C
Thermal shutdown
%
Thermal shutdown hysteresis
THYS
%VO/ΔIO
Load transient response
IO = 100mA to 750mA, TJ =
25°C tR = tF ≥ 200ns, Note 1
-5
+5
%VO
%VO/ΔIO
Short circuit removal response
IO = 10mA to IO = short,
TJ = 25°C Note 1
-10
+10
%VO
Note:
1
Guaranteed by design, but not tested in production
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Electrical characteristics
ST1S06xx
VIN_SW = VIN_A = VINH = 5 V, VO = 3.3 V, CI = 4.7 µF, CO = 22 µF, L1 = 3.3 µH, TJ = -30 °C to
125 °C unless otherwise specified. Typical values are referred to TJ = 25 °C.
Table 7.
Electrical characteristics for ST1S06PM33
Symbol
OUT
Parameter
Test conditions
Output feedback pin
IO
IO pin bias current
VO = 3.5V
VI
Minimum input voltage
IO = 10mA to 1.5A
IQ
Quiescent current
IO
Output current
Min.
Typ.
Max.
Unit
3.23
3.3
3.37
V
15
20
µA
4.2
V
VINH > 1.2V
VINH < 0.4V, TJ = -30°C to 85°C
VINH
Inhibit threshold
VI = 4.2 to 5.5V Note 1
1.5
Device ON, VI = 4.2 to 5.5V
1.3
Device ON, VI = 4.2 to 5V
1.2
mA
1
µA
A
V
Device OFF
IINH
1.5
0.4
Inhibit pin current
2
µA
%VO/ΔVI
Reference line regulation
VI = 4.2V to 5.5V Note 1
0.2
0.3
%VO/
ΔVI
%VO/ΔIO
Reference load regulation
IO = 10mA to 1.5A Note 1
0.2
0.3
%VO/
ΔIO
PWMfS
PWM switching frequency
VFB = 0.8V
1.2
1.5
1.8
MHz
80
87
%
Maximum duty cycle
DMAX
RDSON-N
NMOS switch on resistance
ISW = 750 mA
0.12
Ω
RDSON-P
PMOS switch on resistance
ISW = 750 mA
0.15
Ω
ISWL
Switching current limitation
Note 1
2.3
A
ν
Efficiency Note 1
TSHDN
IO = 10mA to 100mA, VO = 3.3V
65
IO = 100mA to 1.5A, VO = 3.3V
85
90
130
150
°C
15
°C
Thermal shutdown
%
Thermal shutdown hysteresis
THYS
%VO/ΔIO
Load transient response
IO = 100mA to 750mA, TJ =
25°C tR = tF ≥ 200ns, Note 1
-5
+5
%VO
%VO/ΔIO
Short circuit removal response
IO = 10mA to IO = short,
TJ = 25°C Note 1
-10
+10
%VO
Note:
8/20
1
Guaranteed by design, but not tested in production
Doc ID 12236 Rev 9
ST1S06xx
5
Typical performance characteristics
Typical performance characteristics
VIN_SW = VIN_A = VINH = 5 V, CI = 4.7 µF, CO = 22 µF, L1 = 3.3 µH, unless otherwise
specified. Typical values are referred to 25 °C.
Figure 3.
Efficiency vs. output current
Figure 4.
Efficiency vs. output current
Figure 5.
Efficiency vs. output current
Figure 6.
Efficiency vs. output current
Figure 7.
Efficiency vs. output current
Figure 8.
Efficiency vs. inductor
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Typical performance characteristics
Figure 9.
ST1S06xx
Voltage feedback vs. temperature
Figure 10. Input voltage vs. output voltage
Figure 11. Feedback pin bias current vs.
temperature
Figure 12. Quiescent current vs. temperature
Figure 13. Quiescent current vs. temperature
Figure 14. Inhibit voltage vs. input voltage
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ST1S06xx
Typical performance characteristics
Figure 15. Inhibit voltage vs. temperature
Figure 16. Inhibit voltage vs. temperature
Figure 17. Line regulation vs. temperature
Figure 18. Load regulation vs. temperature
Figure 19. PWM switching frequency vs.
temperature
Figure 20. NMOS switch on resistance vs.
temperature
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Typical performance characteristics
ST1S06xx
Figure 21. PMOS switch on resistance vs.
temperature
Figure 22. Inhibit transient
VI = 5 V, VINH = 0 to 2 V, IO = 1.5 A
Figure 23. Inhibit transient
VI = 5 V, VINH = 0 to 2 V, IO = 10 mA
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ST1S06xx
6
Typical application
Typical application
Figure 24. Application circuit
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Application notes
7
ST1S06xx
Application notes
The ST1S06xx is an adjustable current mode PWM step-down DC-DC converter with
internal 1.5 A power switch, packaged in a 6-lead DFN 3x3.
It’s a complete 1.5 A switching regulator with its internal compensation eliminating additional
component.
The constant frequency, current mode, PWM architecture and stable operation with ceramic
capacitors results in low, predictable output ripple. However, in order to maximize the power
conversion efficiency with light load, the regulator reduces automatically the switching
frequency when the output load becomes less than 250 mA typically.
To clamp the error amplifier reference voltage a soft start control block generating a voltage
ramp, has been implemented. Besides an on-chip power on reset of 50 = 100 µs ensure the
proper operation when switching on the power supply. Other circuits fitted to the device
protection are the thermal shut down block which turn off the regulator when the junction
temperature exceeds 150 °C typically and the cycle-by-cycle current limiting that provides
protection against shorted outputs.
Being the ST1S06xx an adjustable regulator, the output voltage is determined by an
external resistor divider. The desired value is given by the following equation:
VO = VFB [1 + R1 / R2]
To make the device working, only few component are required: an inductor and two
capacitors and the resistor divider. The chosen inductor must be able to not saturate at the
peak current level. Besides, its value can be selected keeping in 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 the package
size and the total cost of the application. Finally, the ST1S06xx has been designed to work
properly with X5R or X7R SMD ceramic capacitors both at the input and at the output. this
kind of capacitors, thanks 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 invalidate the right functioning of the device.
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ST1S06xx
8
Package mechanical data
Package mechanical data
In order to meet environmental requirements, ST offers these devices in different grades of
ECOPACK® packages, depending on their level of environmental compliance. ECOPACK®
specifications, grade definitions and product status are available at: www.st.com. ECOPACK
is an ST trademark.
Doc ID 12236 Rev 9
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Package mechanical data
ST1S06xx
DFN6D (3x3 mm) mechanical data
mm.
inch.
Dim.
Min.
A
0.80
A1
0
A3
0.02
Max.
Min.
1.00
0.031
0.05
0
0.20
b
0.23
D
2.90
D2
2.23
E
2.90
E2
1.50
e
L
Typ.
3.00
3.00
0.40
Max.
0.039
0.001
0.002
0.008
0.45
0.009
3.10
0.114
2.50
0.088
3.10
0.114
1.75
0.059
0.95
0.30
Typ.
0.018
0.118
0.122
0.098
0.118
0.122
0.069
0.037
0.50
0.012
0.016
0.020
7946637B
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ST1S06xx
Package mechanical data
Tape and reel QFNxx/DFNxx (3x3 mm) mechanical data
mm.
inch.
Dim.
Min.
Typ.
A
Max.
Min.
Typ.
330
13.2
12.992
C
12.8
D
20.2
0.795
N
60
2.362
T
0.504
0.519
18.4
0.724
Ao
3.3
0.130
Bo
3.3
0.130
Ko
1.1
0.043
Po
4
0.157
P
8
0.315
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Max.
17/20
Package mechanical data
ST1S06xx
Figure 25. DFN6 (3x3 mm) footprint recommended data
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ST1S06xx
Revision history
9
Revision history
Table 8.
Document revision history
Date
Revision
Changes
08-May-2006
1
Initial release.
06-Jun-2006
2
Table 3 updated.
16-Oct-2006
3
Add new mechanical data DFN6D.
09-Nov-2006
4
Mechanical data information for DFN6 update.
03-Apr-2007
5
Tape and reel updated.
12-Mar-2008
6
Added: Table 1 on page 1.
15-Apr-2008
7
Modified: Figure 6 on page 9.
10-Apr-2009
8
Modified: Table 3 on page 5.
06-May-2009
9
Added: marking Table 1 on page 1.
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ST1S06xx
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