Key Selection Information
| Selection Parameter | Confirmed Information |
|---|---|
| Regulator Type | Fixed positive LDO |
| Output Voltage | 3.3 V |
| Output Current | Up to 1 A |
| Maximum Input Voltage | 20 V |
| Quiescent Current | 6 mA typical |
| Protection | Current limiting and thermal protection |
| Package | SOT-223 |
| Exact Orderable | NCP1117ST33T3G, tape and reel |
Product Overview
NCP1117ST33T3G is the fixed 3.3 V SOT-223 member of onsemi’s NCP1117 1 A LDO family. It is intended to generate a regulated 3.3 V rail from a higher DC input while offering the simplicity and low external component count of a linear regulator.
The key engineering constraint is dissipation rather than switching complexity. Linear-regulator heat is approximately the input-to-output voltage drop multiplied by load current, so a nominal 1 A rating cannot be separated from VIN, PCB copper and ambient conditions. In high-drop applications, thermal limits can become dominant well before the electrical current limit.
Technical Specifications
| Group | Parameter | Value / Condition |
|---|---|---|
| Regulator | Topology | Low-dropout linear regulator |
| Output | Nominal voltage | 3.3 V |
| Output | Current | Up to 1 A |
| Input | Maximum voltage | 20 V |
| Supply | Quiescent current | 6 mA typical |
| Protection | Current | Internal current limiting |
| Protection | Thermal | Thermal shutdown / protection |
| Package | Type | SOT-223 |
| Packing | Format | Tape and reel |
Functional Highlights
The fixed 3.3 V output removes the feedback-divider requirement
For systems that specifically need 3.3 V, the fixed option reduces external parts and avoids resistor-tolerance contribution from an adjustable feedback network.
Thermal design determines usable current at high VIN
A large VIN-to-VOUT drop converts directly to package heat. The SOT-223 copper area and ambient temperature therefore matter whenever load current approaches the upper range.
Applications / Application Fit
- 3.3 V point-of-load regulation
- Post-regulation after a switching converter
- Consumer and industrial controller rails with moderate dissipation
Design Considerations
Calculate power dissipation as approximately (VIN − 3.3 V) × IOUT before assuming the 1 A rating is thermally usable.
Follow the manufacturer’s output-capacitor stability requirements and place the capacitor close to the regulator.
Provide adequate SOT-223 copper area for heat spreading and verify junction temperature under worst-case ambient/load conditions.
Related Engineering Resources
- onsemi official product/family page — manufacturer-controlled product information and documentation.
- NCP1117ST33T3G verified Datasheet PDF — identity-verified PDF hosted on HKEQGOO assets.
Alternative Candidates for Engineering Evaluation
| MPN | Manufacturer | Package |
|---|---|---|
| NCV1117ST33T3G | onsemi | SOT-223 |
| AMS1117-3.3 | GR | SOT-223 |
| LT1963AEST-3.3#TRPBF | Analog Devices | SOT-223-3 |
| LT1963AEST-3.3#PBF | Analog Devices | SOT-223 |
| LT1963EST-3.3#PBF | Analog Devices | SOT-223-3 |
Candidate alternative parts require engineering verification before substitution. Electrical characteristics, pinout, package, qualification, and application requirements should be verified before use.
Quality & Verification Support
Third-party inspection or testing can be arranged according to customer requirements. Testing fees are borne by the buyer. Additional verification requirements can be discussed before shipment. After an order is placed, physical product, label, packaging, and Date Code photos may be provided where appropriate.
Request a Quote
To request a quotation, provide the manufacturer part number, required quantity, destination, target Date Code if applicable, and any testing or inspection requirements.
