Document
ST1S10
3 A, 900 kHz, monolithic synchronous step-down regulator IC
DFN8 (4 x 4 mm)
PowerSO-8
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 • Standby supply current: max. 6 µA over
temperature range • Operative junction temp.: from -40 °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
Datasheet - production data
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 (VFB) to 0.85 * VIN_SW [VOUT = VFB * (1 + 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 overcurrent and output short-circuit.
The ST1S10 is the ideal choice for point of load regulators or LDO pre-regulation.
Table 1. Device summary
Order code Part number
DFN8 (4x4 mm) PowerSO-8
ST1S10
ST1S10PUR
ST1S10PHR
February 2020
This is information on a product in full production.
DocID13844 Rev 7
1/30
www.st.com
Contents
Contents
ST1S10
1 Application circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2 Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5 Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
5.1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 5.2 External components selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Input capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 5.3 Output capacitor (VOUT > 2.5 V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11 5.4 Output capacitor (0.8 V < VOUT < 2.5 V) . . . . . . . . . . . . . . . . . . . . . . . . . 12 5.5 Output voltage selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 5.6 Inductor (VOUT > 2.5 V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 5.7 Inductor (0.8 V < VOUT < 2.5 V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 5.8 Function operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.8.1 Sync operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 5.8.2 Inhibit function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 5.8.3 OCP (overcurrent protection) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 5.8.4 SCP (short-circuit protection) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 5.8.5 SCP and OCP operation with high capacitive load . . . . . . . . . . . . . . . . 14
6 Layout considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Thermal considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
7 Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
8 Typical performance characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
9 Package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
9.1 Power SO-8 package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 9.2 DFN8 (4 x 4) package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
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Contents
10 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
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List of tables
List of tables
ST1S10
Table 1..