Part Number: ST1S10PHR

Manufacturer: STMicroelectronics

Description: REG BUCK ADJ 3A

Shipped from: Shenzhen/HK Warehouse

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Technical Specifications of ST1S10PHR

Datasheet  ST1S10PHR datasheet
Category Integrated Circuits (ICs)
Family PMIC – Voltage Regulators – DC DC Switching Regulators
Manufacturer STMicroelectronics
Packaging Tape & Reel (TR)
Part Status Active
Function Step-Down
Output Configuration Positive
Topology Buck
Output Type Adjustable
Number of Outputs 1
Voltage – Input (Min) 2.5V
Voltage – Input (Max) 18V
Voltage – Output (Min/Fixed) 0.8V
Voltage – Output (Max) 16.2V
Current – Output 3A
Frequency – Switching 900kHz
Synchronous Rectifier Yes
Operating Temperature -40°C ~ 125°C (TJ)
Mounting Type Surface Mount
Package / Case 8-SOIC (0.154″, 3.90mm Width) Exposed Pad
Supplier Device Package PowerSO-8

ST1S10PHR Description

The ST1S10 provides up to 3 A of current and is a highly efficient, step-down, PWM current mode switching regulator. The input voltage range for the device is 2.5 V to 18 V, and the output voltage range is from 0.8 V (VFB) to 0.85 * VIN_SW [VOUT = VFB * (1 + R1/R2)]. It runs at a set frequency of 900 kHz or can be synchronized to an external clock with a frequency between 400 kHz and 1.2 MHz. The high switching frequency lets you use small SMD components on the outside, and the built-in synchronous rectifier means you don’t need a Schottky diode. The ST1S10 offers great transient response and is safeguarded against damage caused by excessive heat, excessive switching current, and output short-circuits. The ST1S10 is the best choice for LDO pre-regulation or point-of-load controllers.

ST1S10PHR All features

  • PWM regulator with a step-down current mode.
  • Output voltage is changeable from 0.8 V.
  • From 2.5 V to 18 V can be put in.
  • 2% DC output voltage range.
  • fixing things at the same time.
  • block function.
  • The change frequency can be set to anything between 400 kHz and 1.2 MHz.
  • soft start from the inside.
  • dynamic defense against short circuits.
  • 90% is a typical rate.
  • Three amps of current can be sent out.
  • Standby source current: a maximum of 6 A, regardless of temperature.
  • from -40°C to 125°C (from -40°F to 125°F).

ST1S10PHR Application information

The ST1S10 is a synchronous step-down DC-DC converter with an “inhibit” feature that has a high level of efficiency. It can take an input voltage of 2.5 V to 18 V and give out up to 3 A. The output voltage can be changed from 0.8 V to 85% of the input voltage. With synchronous rectification, you don’t need an extra Schottky diode, and even at very low output voltages, the efficiency is better.

A high internal switching frequency (0.9 MHz) lets you use small surface-mount components and a resistor divider to set the output voltage value. In most applications, all that is needed for proper function is an inductor and three capacitors. Through the SYNC pin, the device can work in PWM mode with a set frequency or in sync with an external frequency. With low ESR SMD ceramic capacitors and a current-mode PWM design, the output ripple is low and easy to predict. No outside payment is necessary.

When the load is low, the ST1S10 works in pulse-skipping mode and then switches automatically to PWM mode to make the most of the power conversion. The ST1S10 has a thermal shutdown safety feature that turns on at 150 °C (typically). Cycle-by-cycle short-circuit safety protects both the application and the regulator against outputs that are too close together. An internal soft start for limiting start-up current and a typical power-on delay of 275 s help to lower start-up inrush current. 5.2 External components: input capacitor

The ST1S10 has two VIN pins: the voltage at which the peak switching current is drawn from the power supply is denoted by VIN_SW, and VIN_A is for powering the internal circuitry and drivers of the ST1S10. The VIN_SW input capacitor mitigates switching noise in the IC by smoothing out current peaks drawn from the input power supply. For a high power supply source resistance, the input capacitance needs to be bigger.

  • Output capacitor (VOUT > 2.5 V)

The capacitance, the equivalent series resistance (ESR), and the voltage value are the most important parts of the output capacitor. Capacitance and ESR affect the stability of the control loop, the ripple voltage at the output, and the regulator’s reaction to sudden changes.

ST1S10PHR Function and Operation

synchronize a task The ST1S10 has a set frequency, but the SYNC pin can be used to sync it to an external frequency. When the SYNC pin is attached to ground, the ST1S10 switches at a rate of 900 kHz. An external clock connected to the SYNC pin can be used to sync the switching rate between 400 kHz and 1.2 MHz. When the SYNC function isn’t being used, this pin must be connected to ground in the shortest way possible to keep noise from getting into the SYNC circuitry.

  • OCP (overcurrent protection)

The ST1S10 DC-DC converter has a switch that protects against too much power. In order to protect the application and the internal power switches and bonding wires, the device shuts down when the switch current limit is reached and stays in this state for the TOFF period (typically 135 s) before turning back on for the TON period (typically 22 s). This action is repeated again and again. When no overcurrent is found, normal functioning is resumed.

  • SCP (short-circuit protection)

The device has built-in dynamic short-circuit safety that works by monitoring the VFB to protect the whole application and lower the total amount of power lost when there is an overload or an output short-circuit. In the case of an overload or output short-circuit, if the VOUT voltage is lowered and the feedback voltage (VFB) drops below 0.3 V (typically), the device shuts down for the TOFF time (TOFF(SCP) = 288 s typ.) and then turns back on for the TON time (TON(SCP) = 130 s typ.). This process is repeated cycle after cycle, and normal operation is restarted when there is no overload for the full TON period (usually VFB > 0.3 V). This dynamic process can reduce power loss by a lot when the system is overloaded, but it can still start up well in most situations.


In conclusion, the ST1S10 is a highly efficient and flexible step-down PWM current mode switching regulator with good transient response and protection against thermal overheating, switching overcurrent, and output short-circuit. It works with an input voltage between 2.5 V and 18 V, and the output voltage can be changed from 0.8 V to 0.85 * VIN_SW. Because of the high switching frequency, small SMD external components can be used, and a Schottky diode is not needed because of the synchronous rectifier. This makes the ST1S10 perfect for LDO pre-regulation or point-of-load controllers. Overall, the ST1S10 is a good choice for a wide range of uses because of its features and how well it works.

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