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 exposed pad DFN6D (3x3 mm) 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 ST1S06 is available in DFN6D 3x3 package. Description The ST1S06 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. Besides, a low output ripple is guaranteed by the Table 1. April 2008 Device summary Part numbers Order codes Package ST1S06 ST1S06PUR DFN6D (3x3 mm) ST1S06A ST1S06APUR DFN6D (3x3 mm) ST1S06XX12 ST1S06PU12R DFN6D (3x3 mm) ST1S06XX33 ST1S06PU33R DFN6D (3x3 mm) Rev 7 1/20 www.st.com 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 2/20 ST1S06xx Diagram 1 Diagram Figure 1. Schematic diagram 3/20 Pin configuration ST1S06xx 2 Pin configuration Figure 2. Pin configuration (top view) ST1S06A ST1S06 Note: * 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 4/20 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 Max. voltage of output pin -0.3 to 7 V Feedback voltage -0.3 to 3 V VO Output voltage (for VO > 1.6 V) -0.3 to 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 SWITCH voltage VFB/VO 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 5/20 Electrical characteristics ST1S06xx 4 Electrical characteristics Table 5. Electrical characteristics for ST1S06 (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) 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 ST1S06xx Table 6. Electrical characteristics Electrical characteristics for ST1S06PM12 (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) 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 % 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 = 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 7/20 Electrical characteristics Table 7. ST1S06xx Electrical characteristics for ST1S06PM33 (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) 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 % 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: 8/20 1 Guaranteed by design, but not tested in production 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 9/20 Typical performance characteristics Figure 9. Voltage feedback vs temperature ST1S06xx 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 10/20 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 11/20 Typical performance characteristics Figure 21. PMOS switch on resistance vs temperature ST1S06xx Figure 22. Inhibit transient VI = 5V, VINH = 0 to 2V, IO = 1.5A Figure 23. Inhibit transient VI = 5V, VINH = 0 to 2V, IO = 10mA 12/20 ST1S06xx 6 Typical application Typical application Figure 24. Application circuit 13/20 Application notes 7 ST1S06xx Application notes The ST1S06 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 cycleby-cycle current limiting that provides protection against shorted outputs. Being the ST1S06 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 ST1S06 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. 14/20 ST1S06xx 8 Package mechanical data 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 box label, in compliance with JEDEC Standard JESD97. The maximum ratings related to soldering conditions are also marked on the inner box label. ECOPACK is an ST trademark. ECOPACK specifications are available at: www.st.com. 15/20 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 16/20 ST1S06xx Package mechanical data Tape & Reel QFNxx/DFNxx (3x3) 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 Max. 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 17/20 Package mechanical data Figure 25. DFN6 (3x3 mm) footprint recommended data 18/20 ST1S06xx 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. 19/20 ST1S06xx Please Read Carefully: 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. 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