IC REG STEPDOWN 3A 900KHZ DFN8

ST1S10PUR

Manufacturer Part NumberST1S10PUR
DescriptionIC REG STEPDOWN 3A 900KHZ DFN8
ManufacturerSTMicroelectronics
TypeStep-Down (Buck)
ST1S10PUR datasheet
 


Specifications of ST1S10PUR

Internal Switch(s)YesSynchronous RectifierYes
Number Of Outputs1Voltage - Output0.8 ~ 15.3 V
Current - Output3AFrequency - Switching900kHz
Voltage - Input2.5 ~ 18 VOperating Temperature-25°C ~ 125°C
Mounting TypeSurface MountPackage / Case8-DFN
Output Voltage0.8 V to 15.3 VOutput Current3 A
Input Voltage2.5 V to 18 VSwitching Frequency0.9 MHz
Operating Temperature Range- 25 C to + 125 CMounting StyleSMD/SMT
Duty Cycle (max)90 %For Use With497-8407 - BOARD EVAL STP04CM05/ST1S10497-8216 - BOARD EVAL BASED ON ST1S10497-8229 - BOARD EVAL BASED ON ST1S10
Lead Free Status / RoHS StatusLead free / RoHS CompliantPower - Output-
Other names497-6313-2  
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Features
Step-down current mode PWM regulator
Output voltage adjustable from 0.8 V
Input voltage from 2.5 V up to 18 V
2% DC output voltage tolerance
Synchronous rectification
Inhibit function
Synchronizable switching frequency from 400
kHz up to 1.2 MHz
Internal soft start
Dynamic short circuit protection
Typical efficiency: 90%
3 A output current capability
Stand-by supply current: max 6 µA over
temperature range
Operative junction temp: from - 25 °C to 125 °C
Applications
Consumer
– STB, DVD, DVD recorders, TV, VCR, car
audio, LCD monitors
Networking
– XDSL, modems, DC-DC modules
Computer
– Optical storage, HD drivers, printers,
audio/graphic cards
Industrial and security
– Battery chargers, DC-DC converters, PLD,
PLA, FPGA, LED drivers
Table 1.
Device summary
Part number
ST1S10
March 2011
3 A, 900 kHz, monolithic synchronous
step-down regulator IC
DFN8 (4 x 4 mm)
Description
The ST1S10 is a high efficiency step-down PWM
current mode switching regulator capable of
providing up to 3 A of output current. The device
operates with an input supply range from 2.5 V to
18 V and provides an adjustable output voltage
from 0.8 V (V
) to 0.85*V
FB
R1 / R2)]. It operates either at a 900 kHz fixed
frequency or can be synchronized to an external
clock (from 400 kHz to 1.2 MHz). The high
switching frequency allows the use of tiny SMD
external components, while the integrated
synchronous rectifier eliminates the need for a
Schottky diode. The ST1S10 provides excellent
transient response, and is fully protected against
thermal overheating, switching over-current and
output short circuit. The ST1S10 is the ideal
choice for point-of-load regulators or LDO pre-
regulation.
Order codes
DFN8 (4 x 4 mm)
ST1S10PUR
Doc ID 13844 Rev 4
ST1S10
PowerSO-8
[V
= V
*(1 +
IN_SW
OUT
FB
PowerSO-8
ST1S10PHR
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www.st.com
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ST1S10PUR Summary of contents

  • Page 1

    ... Schottky diode. The ST1S10 provides excellent transient response, and is fully protected against thermal overheating, switching over-current and output short circuit. The ST1S10 is the ideal choice for point-of-load regulators or LDO pre- regulation. Order codes DFN8 ( mm) ST1S10PUR Doc ID 13844 Rev 4 ST1S10 PowerSO *(1 + IN_SW ...

  • Page 2

    Contents Contents 1 Application circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...

  • Page 3

    ST1S10 1 Application circuit Figure 1. Typical application circuit 12V 12V VIN_SW VIN_SW 4.7µF 4.7µF VIN_A VIN_A C3 C3 0.1µF 0.1µ ST1S10 ST1S10 FB FB SYNC SYNC AGND AGND PGND PGND Doc ID 13844 ...

  • Page 4

    Pin configuration 2 Pin configuration Figure 2. Pin connections (top view for PowerSO-8, bottom view for DFN8) DFN8 (4x4) Table 2. Pin description Pin n° Symbol 1 V IN_A 2 INH (EN AGND 5 SYNC 6 ...

  • Page 5

    ST1S10 3 Maximum ratings Table 3. Absolute maximum ratings Symbol V Positive power supply voltage IN_SW V Positive supply voltage IN_A V Inhibit voltage INH V Output switch voltage SW V Feedback voltage current FB Sync Synchronization ...

  • Page 6

    Electrical characteristics 4 Electrical characteristics IN_SW +0.1 µ µ 3.3 µH, T OUT the typical application circuit. Typical values assume T Table 5. Electrical characteristics Symbol Parameter V Feedback ...

  • Page 7

    ST1S10 Table 5. Electrical characteristics (continued) Symbol Parameter I I SYNC input current IL, IH UVLO Under voltage lock-out threshold 1. Guaranteed by design, but not tested in production. 2. See output voltage selection paragraph 5.5 for maximum duty cycle ...

  • Page 8

    Application information 5 Application information 5.1 Description The ST1S10 is a high efficiency synchronous step-down DC-DC converter with inhibit function. It provides over an input voltage range of 2 and the output ...

  • Page 9

    ST1S10 Equation OUT F where V is the voltage drop across the internal NMOS, and V F drop across the internal PDMOS. The minimum duty cycle (at V duty cycle (at ...

  • Page 10

    Application information reduce ripple voltages due to the parasitic inductive effect, the output capacitor connection paths should be kept as short as possible. The ST1S10 has been designed to perform best with ceramic capacitors. Under typical application conditions a minimum ...

  • Page 11

    ST1S10 Equation {[ OUT OUT is the junction-to-ambient thermal resistance, η is the efficiency at the rated where R thJA I current and T OUT To ensure safe operating conditions the application should be ...

  • Page 12

    Application information 5.8.2 Inhibit function The inhibit pin can be used to turn OFF the regulator when pulled down, thus drastically reducing the current consumption down to less than 6 µA. When the inhibit feature is not used, this pin ...

  • Page 13

    ST1S10 Figure 3. Application schematic for heavy capacitive load 12V 12V VIN_SW VIN_SW 10µF 10µF VIN_A VIN_A C3 C3 4.7µF 4.7µF (*) see OCP and SCP descriptions for C2 and C4 selection Figure 4. Application schematic ...

  • Page 14

    Layout considerations 6 Layout considerations Layout is an important step in design for all switching power supplies. High-speed operation (900 kHz) of the ST1S10 device demands careful attention to PCB layout. Care must be taken in board layout to get ...

  • Page 15

    ST1S10 Figure 7. PCB layout suggestion 6.1 Thermal considerations The lead frame die pad, of ST1S10, is exposed at the bottom of the package and must be soldered directly to a properly designed thermal pad on the PCB, the addition ...

  • Page 16

    Diagram 7 Diagram Figure 8. Block diagram 16/26 Doc ID 13844 Rev 4 ST1S10 ...

  • Page 17

    ST1S10 8 Typical performance characteristics Unless otherwise specified, refer to the typical application circuit under the following conditions 25° mA, C OUT IN Figure 9. Voltage feedback vs. temperature 830 830 830 820 ...

  • Page 18

    Typical performance characteristics Figure 15. ON mode quiescent current vs. temperature 1.8 1.8 1.6 1.6 1.4 1.4 1.2 1 0.8 0.8 0.6 0.6 0.4 0 =12V, V =12V, V =1.2V, V =1.2V, V IN-A ...

  • Page 19

    ST1S10 Figure 21. Efficiency vs. output current 100 100 =5V, V =5V, V IN-A IN-A IN-SW IN-SW INH INH 0.5 0.5 1 ...

  • Page 20

    Package mechanical data 9 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 ...

  • Page 21

    ST1S10 PowerSO-8 (exposed pad) mechanical data Dim ccc mm. Min. Typ. 0.00 1.25 0.31 0.17 4.80 4.90 ACCORDING TO PAD SIZE 5.80 6.00 3.80 3.90 ACCORDING ...

  • Page 22

    Package mechanical data Dim. Min 0.23 D 3.90 D2 2.82 E 3. 0.40 22/26 DFN8 (4x4) mechanical data mm. Typ. Max. 0.90 1.00 0.02 0.05 0.20 0.30 0.38 4.00 4.10 ...

  • Page 23

    ST1S10 Dim. Min 12 8.1 Bo 5.5 Ko 2.1 Po 3.9 P 7.9 Tape & reel SO-8 mechanical data mm. Typ. Max. 330 13.2 22.4 8.5 5.9 2.3 4.1 8.1 Doc ID ...

  • Page 24

    Package mechanical data Tape & reel QFNxx/DFNxx (4x4) mechanical data Dim. Min 12 24/26 mm. Typ. Max. Min. 330 13.2 0.504 0.795 101 3.898 14.4 4.35 4.35 1.1 ...

  • Page 25

    ST1S10 10 Revision history Table 6. Document revision history Date Revision 28-Aug-2007 1 24-Sep-2007 2 25-Oct-2007 3 10-Mar-2011 4 Initial release. Add R on Table 4. thJC Added new paragraph 6: Layout considerations. Updated PowerSO-8 package mechanical data and Doc ...

  • Page 26

    ... Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. All ST products are sold pursuant to ST’s terms and conditions of sale. ...