ST1S12XX18

Manufacturer Part NumberST1S12XX18
DescriptionSynchronous rectification with enable, 0.7 A, 1.7 MHz fixed or adjustable step-down switching regulator in TSOT23-5L
ManufacturerSTMICROELECTRONICS [STMicroelectronics]
ST1S12XX18 datasheet
 


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Synchronous rectification with enable, 0.7 A, 1.7 MHz fixed or
adjustable step-down switching regulator in TSOT23-5L
Features
Step-down current mode PWM (1.7 MHz) DC-
DC converter
3% DC output voltage tolerance
Synchronous rectification
Fixed output voltage 1.2 V, 1.8 V, and ADJ
(available on request 1.5 V, 2.5 V and 3.3 V)
Enable function
Internal soft start
Typical efficiency: > 90%
0.7 A output current capability
Not switching quiescent current: max 600 µA
over temperature range
R
typ. 250 mΩ and 400 mΩ
DSON
Uses tiny capacitors and inductors
Operative junction temp. -40°C to 125°C
Available in TSOT23-5L package
Description
The ST1S12Gxx is a step down DC-DC converter
optimized for powering low-voltage digital cores in
HDD applications and, generally, to replace the
high current linear solution when the power
dissipation may cause high heating of the
application environment. It provides up to 0.7 A
over an input voltage range of 2.5 V to 5.5 V. A
high switching frequency (1.7 MHz) allows the
use of tiny surface-mount components. In addition
to the resistor divider to set the output voltage
value, only an inductor and two capacitors are
Table 1.
Device summary
Part numbers
ST1S12XX
ST1S12XX12
ST1S12XX18
1. Available on request.
February 2008
TSOT23-5L
required. Moreover, 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 thermally protected and
the current is limited to prevent damage due to
accidental short-circuit. The ST1S12Gxx is
available in the TSOT23-5L package.
Order codes
ST1S12GR
ST1S12G12R
(1)
ST1S12G18R
Rev 2
ST1S12xx
Package
TSOT23-5L
TSOT23-5L
TSOT23-5L
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ST1S12XX18 Summary of contents

  • Page 1

    ... Table 1. Device summary Part numbers ST1S12XX ST1S12XX12 ST1S12XX18 1. Available on request. February 2008 TSOT23-5L required. Moreover, a low output ripple is guaranteed by the current mode PWM topology and by the use of low ESR SMD ceramic capacitors ...

  • Page 2

    Contents 1 Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...

  • Page 3

    Schematic Figure 1. Schematic diagram V Σ SUM V C SOFT START REF1 V IN UVLO V RST Comp MOSFET V DRV_P CONTROL LOGIC V SET OSC SHUT DOWN I_SEN R sense - Driver ...

  • Page 4

    Pin configuration Figure 2. Pin connections (top view) Table 2. Pin description Pin n° Symbol GND FB/V O 4/20 Name and function Enable pin System ground Switching pin Input supply ...

  • Page 5

    Maximum ratings Table 3. Absolute maximum ratings Symbol V Positive power supply voltage IN V Enable voltage EN SWITCH Voltage Max. voltage of output pin V /V Feedback voltage Output voltage (for Max ...

  • Page 6

    Electrical characteristics Table 6. Electrical characteristics for ST1S12G 3 specified. Typical values are referred to 25 °C) Symbol Parameter FB Feedback voltage I V pin bias current Minimum input ...

  • Page 7

    Table 7. Electrical characteristics for ST1S12G12 specified. Typical values are referred to 25 °C) Symbol Parameter OUT Output feedback pin I V pin bias current Minimum input voltage ...

  • Page 8

    Table 8. Electrical characteristics for ST1S12G18 3 specified. Typical values are referred to 25 °C) Symbol Parameter OUT Output feedback pin I V pin bias current Minimum input voltage IN ...

  • Page 9

    Typical application Figure 3. Application circuit 9/20 ...

  • Page 10

    Application notes The ST1S12Gxx is an adjustable current mode PWM step-down DC-DC converter with internal 0.7 A power switch, packaged in TSOT23-5L. This device is a complete 0.7 A switching regulator, with its internal compensation eliminating the need for ...

  • Page 11

    Typical performance characteristics Unless otherwise specified, refer to the typical application circuit under the following conditions 4.7 µ Figure 4. Voltage feedback vs temperature 650 650 =3.6V, I =3.6V, I =10mA, ...

  • Page 12

    Figure 10. Efficiency vs temperature 100 100 =3V, V =3V, V =1.2V =1. OUT ...

  • Page 13

    Figure 16. Reference load regulation vs temperature 0.005 0.005 V V =3.6V, I =3.6V, I from 10mA to 0.7A, V from 10mA to 0.7A OUT OUT 0.004 0.004 0.003 0.003 0.002 0.002 0.001 0.001 0 0 -75 ...

  • Page 14

    Figure 22. Line transient from 4 5 350 mA OUT 10µ 1.8 V OUT Figure 24. Start-up transient from ...

  • Page 15

    Package mechanical data In order to meet environmental requirements, ST offers these devices in ECOPACK packages. These packages have a lead-free second level interconnect. The category of second level interconnect is marked on the package and on the inner ...

  • Page 16

    Dim. Min 0.7 b 0 0.3 16/20 TSOT23-5L mechanical data mm. Typ. Max. 1.1 0.1 1.0 0.5 0.2 2.9 2.8 1.6 0.95 1.9 0.6 mils. Min. Typ. Max. ...

  • Page 17

    Tape & reel TSOT23-5L mechanical data mm. Dim. Min. Typ 12.8 13 3.13 3.23 Bo 3.07 3.17 Ko 1.27 1.37 Po 3.9 4.0 P 3.9 4.0 inch. Max. Min. Typ. 180 13.2 ...

  • Page 18

    Figure 26. TSOT23-5L footprint recommended data Table 9. Footprint data 18/20 Values mm. 3.50 1.10 0.60 0.95 1.20 2.30 inch. 0.138 0.043 0.024 0.037 0.047 0.090 ...

  • Page 19

    Revision history Table 10. Document revision history Date Revision 10-Jan-2008 1 01-Feb-2008 2 Changes Initial release. Modified: Figure 3 on page 9. 19/20 ...

  • Page 20

    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 ...