Overview
The ST1S40IDR, produced by STMicroelectronics, is an internally compensated 850 kHz fixed-frequency PWM synchronous step-down regulator. This device operates from an input voltage range of 4.0 V to 18 V and can regulate an output voltage as low as 0.8 V and up to the input voltage (VIN). It integrates a 95 mΩ high side switch and a 69 mΩ synchronous rectifier, enabling high efficiency even at very low output voltages. The ST1S40IDR is designed for compact solutions with a minimum component count, thanks to its peak current mode control with internal compensation.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| DC Output Current | 3 A | A |
| Input Voltage Range | 4.0 V to 18 V | V |
| Output Voltage Range | 0.8 V to VIN | V |
| Switching Frequency | 850 kHz | kHz |
| High Side Switch ON Resistance | 95 mΩ | mΩ |
| Low Side Switch ON Resistance | 69 mΩ | mΩ |
| Maximum Limiting Current | 4.0 A to 6.0 A | A |
| Maximum Duty Cycle | 100 % | % |
| Feedback Voltage | 0.784 V to 0.816 V | V |
| Quiescent Current | 1.5 mA to 2.5 mA | mA |
| Enable Threshold Voltage | 1.2 V (ON), 0.4 V (OFF) | V |
| Operating Junction Temperature Range | -40 °C to 150 °C | °C |
| Package Options | VFQFPN 4x4-8L, HSOP-8, SO-8 |
Key Features
- Internally compensated 850 kHz fixed-frequency PWM synchronous step-down regulator
- High efficiency with integrated 95 mΩ high side switch and 69 mΩ synchronous rectifier
- Internal soft-start to limit inrush current during startup
- Cycle-by-cycle current limiting and current fold back short-circuit protection
- All ceramic capacitor compatible
- Enable input for on/off control
- Peak current mode control with internal compensation for a compact solution
- Available in VFQFPN 4x4-8L, HSOP-8, and SO-8 packages
Applications
- Microprocessor (µP), ASIC, DSP, and FPGA core and I/O supplies
- Point of load for set-top boxes (STB), TVs, DVD players
- Optical storage devices, hard disk drives, printers
- Audio and graphic cards
- Communications equipment and personal electronics
- Industrial and automotive applications
Q & A
- What is the input voltage range of the ST1S40IDR?
The input voltage range is from 4.0 V to 18 V.
- What is the maximum output current of the ST1S40IDR?
The maximum output current is 3 A.
- What is the switching frequency of the ST1S40IDR?
The switching frequency is 850 kHz.
- Does the ST1S40IDR have internal soft-start and overcurrent protection?
- What are the package options for the ST1S40IDR?
The device is available in VFQFPN 4x4-8L, HSOP-8, and SO-8 packages.
- What is the operating junction temperature range of the ST1S40IDR?
The operating junction temperature range is from -40 °C to 150 °C.
- Can the ST1S40IDR be used in automotive applications?
- How does the ST1S40IDR regulate output voltage?
The output voltage is regulated by comparing the feedback pin voltage with an internal 0.8 V reference.
- What is the quiescent current of the ST1S40IDR?
The quiescent current is between 1.5 mA and 2.5 mA.
- Does the ST1S40IDR support all ceramic capacitors?
