ST2S06
Dual synchronous rectification with reset or inhibit, 0.5 A, 1.5 MHz
adjustable step-down switching regulator
Datasheet - production data
Description
The ST2S06A33 and ST2S06B are dual stepdown DC-DC converters optimized for powering
low-voltage digital cores in ODD applications and,
generally, to replace high current linear solutions
when the power dissipation may cause high
heating of the application environment. It provides
up to 0.5 A over an input voltage range of 2.5 V to
5.5 V.
QFN12L (4 x 4 mm)
Features
Step-down current mode PWM (1.5 MHz) DCDC converter
Fixed or adjustable output voltage from 0.8 V
2% DC output voltage tolerance
A high switching frequency of 1.5 MHz allows the
use of tiny surface-mount components as well as
a resistor divider to set the output voltage value.
Only an inductor and two capacitors are required.
A low output ripple is guaranteed by the current
mode PWM topology and the utilization of low
ESR SMD ceramic capacitors. The devices are
thermally protected and current-limited to prevent
damage due to accidental short-circuit. The
ST2S06A33 and ST2S06B are available in the
QFN12L (4x4 mm) package.
Synchronous rectification
Reset function for A version
Inhibit function for B version
Internal soft start for startup current limitation
and power ON delay of 50-100 µs
Typical efficiency: > 90%
0.5 A output current capability
Non-switching quiescent current: max 1.2 mA
over temperature range
RDS(ON) 150 m (typ.)
Uses tiny capacitors and inductors
Available in QFN12L (4x4 mm)
Table 1. Device summary
Order codes
Package
Packaging
QFN12L (4 x 4 mm)
Tape and reel
ST2S06A33PQR
ST2S06BPQR
May 2013
This is information on a product in full production.
DocID13866 Rev 6
1/18
www.st.com
Contents
ST2S06
Contents
1
Schematic diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2
Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3
Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4
Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5
Typical performance characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
6
Typical application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
7
Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
8
Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
9
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2/18
DocID13866 Rev 6
ST2S06
1
Schematic diagram
Schematic diagram
Figure 1. Schematic diagram
RESET_OUT *
VI_SW
VI_A
Delay
Ref
SW
HV
Trimming
FB1
VI_SW
SW2
FB2
CONTROL
LOGIC
Ref
Soft Start
GND
INH**
GND
* ST2S06A33
** ST2S06B
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3/18
18
Pin configuration
2
ST2S06
Pin configuration
Figure 2. Pin connections (top view)
Table 2. Pin description
4/18
Pin n°
ST2S06A33
ST2S06B
Name and function
1
HV
HV
Programing pin. It must be floating or connected to GND.
2
FB2
FB2
Feedback voltage
3
GND2
GND2
Power ground
4
SW2
SW2
Switching pin
5
VIN_SW
VIN_SW
6
SW1
SW1
Switching pin
7
GND1
GND1
Power ground
8
FB1/OUT1
FB1
Feedback voltage / output voltage
9
Reset_out
NC
Reset out pin
10
NC
INH
Inhibit pin
11
VIN_A
VIN_A
Supply for analog circuit
12
GND_A
GND_A
System ground
Power input voltage pin
DocID13866 Rev 6
ST2S06
3
Maximum ratings
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 7
V
-0.3 to 7
V
-0.3 to 2.5
V
-0.3 to 5
V
+1 to -1
mA
150
°C
-65 to +150
°C
300
°C
SWITCH voltage Max. voltage of output pin
VFB1,2/VO1
Feedback voltage/output voltage
Output voltage (for VO > 1.6 V)
VO1
Current into VFB
Common mode input voltage
pin
Max junction temperature
TJ
Note:
TSTG
Storage temperature range
TLEAD
Lead temperature (soldering) 10 sec.
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
RthJC
Thermal resistance junction-case
10
°C/W
RthJA
Thermal resistance junction-ambient
60
°C/W
Table 5. ESD performance
Symbol
ESD
Parameter
ESD protection voltage
Test conditions
HBM-DH11C
DocID13866 Rev 6
Value
Unit
4
kV
5/18
18
Electrical characteristics
4
ST2S06
Electrical characteristics
VIN_SW = VIN_A = 5 V, V01 = 3.3 V, VO2 = 1.2 V, C1 = 4.7 µF, C2 = C3 = 22 µF, L1 = L2 = 3.3
µH, TJ = - 30 to 125 °C unless otherwise specified. Typical values are referred to 25 °C.
Table 6. Electrical characteristics for the ST2S06A33
Symbol
Min.
Typ.
Max.
Unit
Output feedback pin
3.23
3.3
3.37
V
FB2
Feedback voltage
784
800
816
mV
IO1
IO1 pin bias current
VO = 3.5 V
15
20
µA
IFB2
VFB pin bias current
VFB = 1 V
600
nA
Quiescent current
VFB = 1 V
1.2
mA
IO1,2
Output current
VIN = 4 to 5.5 V (1)
IMIN
Minimum output current
OUT1
IQ
%VO1,2/VI
Parameter
Test conditions
A
1
Reference line regulation
4V < VIN < 5.5 V
VO1,2
Reference load regulation
10mA < IO < 0.5 A
PWM fS
PWM switching
frequency(1)
VFB = 0.7 V, TA = 25°C
DMAX
Maximum duty cycle
VFB = 0.7 V, TA = 25°C
ISWL
Switching current limitation
ILKN
NMOS leakage current
ILKP
PMOS leakage current
N
0.8
mA
%VO/
VIN
0.032
5.5
15
mV
1.2
1.5
1.8
MHz
85
94
%
1
1.2
A
VFB = 0.9 V, TA = 25°C
0.1
µA
VFB = 0.9 V, TA = 25°C
0.1
µA
RDSon-N
NMOS switch on resistance ISW = 250 mA
0.15
0.3
W
RDSon-P
PMOS switch on resistance ISW = 250 mA
0.2
0.4
W
Efficiency
TSHDN
Thermal shut down
THYS
Thermal shut down
hysteresis (2)
IO = 20 mA to 100 mA
75
%
IO = 100 mA to 0.5 A
90
%
150
°C
15
°C
(2)
VO1,2/IO Load transient response (2)
130
100 mA < IO < 500 mA
tR = tF => 100 ns, TA = 25°C
-5
+5
%VO
Reset section
tDEL
Delay time
TA = 25°C
80
85
Reset in threshold
measured on input pin
VIN_A Rising
4.5
4.6
4.75
VRES
VIN_A Falling
4.12
4.2
4.28
1. VO = 90% of nominal value.
2. Guaranteed by design, but not tested in production.
6/18
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ms
V
ST2S06
Electrical characteristics
VIN_SW = VIN_A = 5 V, VO1,2 =1.2 V, C1= 4.7 µF, C2 = C3 = 22 µF, L1 = L2 = 3.3 µH,
TJ = -30 to 125 °C unless otherwise specified. Typical values are referred to 25 °C.
Table 7. Electrical characteristics for the ST2S06B
Symbol
Parameter
Test conditions
FB1,2
Feedback voltage
IFB1,2
VFB pin bias current
IQ
Quiescent current
IO1,2
Output current
IMIN
Minimum output current
VINH
Min.
Typ.
Max.
Unit
784
800
816
mV
600
nA
VINH > 1.2 V, VFB = 1 V
1
mA
VINH < 0.4 V
1
µA
VFB = 1 V
VIN = 2.5 to 5.5 V
Inhibit threshold
(1)
0.8
1
2.5V < VIN < 5 V
1.2
2.5V < VIN < 5.5 V
1.3
mA
V
Device OFF
IINH1,2
A
0.4
Inhibit pin current
2
µA
%VO1,2/
VIN
Reference line regulation
2.5V < VIN < 5.5 V
0.032
%VO/
VIN
VO1,2
Reference load regulation
10 mA < IO < 0.5 A
5.5
15
mV
PWM fS
PWM switching
frequency(1)
VFB = 0.7 V, TA = 25°C
1.2
1.5
1.8
MHz
DMAX
Maximum duty cycle
VFB = 0.7 V, TA = 25°C
85
94
%
ISWL
Switching current limitation
1
1.2
A
ILKN
NMOS leakage current
VFB = 0.9 V, TA = 25°C
0.1
µA
ILKP
PMOS leakage current
VFB = 0.9 V, TA = 25°C
0.1
µA
RDSon-N
NMOS switch on resistance ISW = 250 mA
0.15
0.3
W
RDSon-P
PMOS switch on resistance ISW = 250 mA
0.2
0.4
W
Efficiency
TSHDN
Thermal shut down
THYS
Thermal shut down
hysteresis (1)
IO = 20 mA to 100 mA
75
%
IO = 100 mA to 0.5 A
90
%
150
°C
15
°C
(2)
VO1,2/IO Load transient response (1)
130
100 mA < IO < 500 mA,
tR = tF1 => 100 ns, TA = 25°C
-5
+5
%VO
1. VO= 90% of nominal value.
2. Guaranteed by design, but not tested in production.
DocID13866 Rev 6
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Typical performance characteristics
5
ST2S06
Typical performance characteristics
Figure 3. Feedback voltage 1 vs. temperature
(ST2S06B)
Figure 4. Feedback voltage 2 vs. temperature
(ST2S06B)
0.82
0.82
VI=5V, VFB1 connected to VO1
IO1=IO2=NO LOAD
VI=5V, VFB2 connected to VO2
IO1=IO2 =NO LOAD
0.81
VFB2 [V]
VFB1 [V]
0.81
0.8
0.79
0.8
0.79
0.78
0.78
-50
-25
0
25
50
75
100
125
-50
-25
0
TEMPERATURE [°C]
VI=5V, VO1=3.3V, IO2 NO LOAD
0
0.1
0.2
0.3
0.4
0.5
100
95
90
85
80
75
70
65
60
55
50
45
40
0.6
0
Frequency [MHz]
Duty Cycle [%]
0
25
50
75
100
125
100
99
98
97
96
95
94
93
92
91
90
0.1
0.2
0.3
0.4
0.5
0.6
VI=5V, VFB1=3.2V, VFB2=0.7V
-50
Temperature [°C]
8/18
125
Figure 8. Duty cycle vs. temperature
(ST2S06A33)
VI=5V, VFB1=3.2V, VFB2=0.7V
-25
100
Output Current 2 [A]
Figure 7. Switching frequency vs. temperature
(ST2S06A33)
-50
75
VI=5V, VO2=1.2V, IO1 NO LOAD
Output Current 1 [A]
1.9
1.8
1.7
1.6
1.5
1.4
1.3
1.2
1.1
50
Figure 6. Efficiency vs. output current 2
EFFICIENCY [%]
EFFICIENCY [%]
Figure 5. Efficiency vs. output current 1
100
95
90
85
80
75
70
65
60
25
TEMPERATURE [°C]
-25
0
25
50
Temperature [°C]
DocID13866 Rev 6
75
100
125
ST2S06
Typical performance characteristics
1.9
1.8
1.7
1.6
1.5
1.4
1.3
1.2
1.1
Figure 10. Inhibit threshold vs. temperature
(ST2S06B)
1.4
VI=5V, IO1= IO2=100mA
1.2
ON
1
VINH (V)
Frequency [MHz]
Figure 9. Switching frequency vs. temperature
(ST2S06B)
0.8
OFF
0.6
0.4
0.2
0
-50
-25
0
25
50
75
100
-50
125
-25
0
25
Figure 11. Switching current limitation vs. input
voltage (ST2S06A33)
75
100
125
Figure 12. PMOS switch on resistance vs.
temperature
2
240
VI from 2.5V to 5.5V, Output2 Maximum load Current
RDSON -P[mOhm]
1.8
ISW2 [A]
50
T [C°]
Temperature [°C]
1.6
1.4
1.2
VCC=5V, ISW=250mA
220
200
180
160
140
120
1
100
2.5
3
3.5
4
4.5
5
5.5
-50
-25
0
25
50
75
100
125
T [°C]
VI [V]
Figure 13. NMOS switch on resistance vs.
temperature
Figure 14. Delay time vs. temperature
(ST2S06A33)
RDSON -N[mOhm]
170
150
130
VI
110
VCC=5V, ISW=250mA
90
VRES
70
50
-50
-25
0
25
50
75
100
125
T [°C]
VI Rising from 0V to 5V, Delay from VRES threshold and
reset pin below 0V.
DocID13866 Rev 6
9/18
18
Typical performance characteristics
ST2S06
100
95
90
85
80
75
70
65
60
55
50
Figure 16. Reset in threshold vs. temperature
(ST2S06A33)
VRES (V)
TDEL (ms)
Figure 15. Delay time vs. temperature
(ST2S06A33)
VI Rising from 0V to 5V
-50
-25
0
25
50
75
100
5
4.9
4.8
4.7
4.6
4.5
4.4
4.3
4.2
4.1
4
Rising
Falling
-50
125
-25
0
25
50
75
100
T [C°]
T [C°]
Figure 17. Load transient response
(ST2S06A33)
Figure 18. Startup transient (ST2S06A33)
VI
VO1
VO1
IO1
VI= from 0V to 5V, IO1=500mA, Output Voltage=3.3V
VI= 5V, IO1 from 100mA to 500mA
Figure 19. Startup transient (ST2S06B)
Figure 20. Inhibit transient (ST2S06B)
VINH
IO1
VI
VO1
VO1
VO2
VI= from 0V to 5V, IO1 =1A, Output Voltage=1.2V
10/18
VINH= from 0V to 2V, VI=5V, IO1=IO2=1A
DocID13866 Rev 6
125
ST2S06
Typical application
6
Typical application
Figure 21. Application circuit for the ST2S06A33
V IN
3.3 µH
L2
VIN_A
SW2
VIN_SW
VFB2
R3
V O2
L1
3.3 µH
ST2S06A33
SW1
NC
R1
V O1
VFB1
Reset_Out
GND1 GND2 HV
GND_A
C1
4.7 µF
C2
22 µF
R2
C3
R4
22 µF
R3
VO2
Figure 22. Application circuit for ST2S06B
L2
VIN
VIN_A
SW2
VIN_SW
VFB2
L1
3.3µH
ST2S06B
INH
C1
4.7µF
NC
GND1 GND2 HV
3.3µH
SW1
R1
VFB1
VO1
GND_A
R2
DocID13866 Rev 6
C2
22µF
R4
C3
22µF
11/18
18
Application information
7
ST2S06
Application information
The ST2S06A33 and ST2S06B represent a series of dual adjustable current mode PWM
step-down DC-DC converters with an internal 0.5 A power switch, packaged in a QFN12L
(4x4 mm).
It is a complete 0.5 A switching regulator with internal compensation that eliminates the
need for additional components.
The constant frequency, current mode, PWM architecture and stable operation with ceramic
capacitors results in low, predictable output ripple.
To clamp the error amplifier reference voltage a soft start control block generating a voltage
ramp has been implemented. 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 that provides protection against shorted
outputs.
The output voltage is determined by an external resistor divider, as the ST2S06A33 and
ST2S06B are adjustable regulators. The desired value is given by the following equation:
VO = VFB [1+R1/R2]
Operation of the device requires few components: 2 inductors, 3 capacitors and a resistor
divider. The chosen inductor must be capable of not saturating at the peak current level. Its
value should be selected keeping in mind 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 total application cost. Finally, the
ST2S06A33 and ST2S06B have 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 functionality of the device. Due to the high switching frequency and peak current, it is
important to optimize the application environment by reducing the length of the PCB traces
and placing all the external components near the device.
Figure 23. Reset function
VIN
VTH
VTL
tDEL
Reset
12/18
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ST2S06
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.
DocID13866 Rev 6
13/18
18
Package mechanical data
ST2S06
QFN12L (4x4) mechanical data
mm.
inch.
Dim.
Min.
Typ.
Max.
Min.
Typ.
Max.
0.80
0.90
1.00
0.031
0.035
0.039
A1
0.02
0.05
0.001
0.002
A3
0.20
A
0.008
b
0.25
0.30
0.35
0.010
0.012
0.014
D
3.90
4.00
4.10
0.154
0.157
0.161
D2
2.00
2.15
2.25
0.079
0.085
0.089
E
3.90
4.00
4.10
0.154
0.157
0.161
E2
2.00
2.15
2.25
0.079
0.085
0.089
e
L
0.80
0.45
0.55
0.031
0.65
0.018
0.022
0.026
7936361B
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ST2S06
Package mechanical data
Tape & reel QFNxx/DFNxx (4x4) mechanical data
mm.
inch.
Dim.
Min.
Typ.
A
Max.
Min.
Typ.
330
C
12.8
D
20.2
N
99
13.2
Max.
12.992
0.504
0.519
0.795
101
T
3.898
3.976
14.4
0.567
Ao
4.35
0.171
Bo
4.35
0.171
Ko
1.1
0.043
Po
4
0.157
P
8
0.315
DocID13866 Rev 6
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18
Package mechanical data
ST2S06
Figure 24. QFN12L (4x4 mm) footprint recommended data
16/18
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ST2S06
9
Revision history
Revision history
Table 8. Document revision history
Date
Revision
Changes
3-Sep-2007
1
Initial release.
21-Jan-2008
2
Added root part number ST2S06D33.
18-Mar-2008
3
Modified: Table 2 on page 4.
28-Jul-2009
4
Modified: Table 1 on page 1.
24-May-2012
5
– Changed max value for Non-switching quiescent current to 1.2 mA in
Features on page 1.
– Updated part number in Figure 21 on page 11
– Minor text changes throughout the document
22-May-2013
6
– Changed title in cover page
DocID13866 Rev 6
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ST2S06
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