仕様
| 属性 | 値 |
| Package | Tube |
| ProductStatus | Not For New Designs |
| OutputConfiguration | Positive |
| OutputType | Fixed |
| NumberofRegulators | 1 |
| Voltage-Input(Max) | 7.5V |
| Voltage-Output(Min/Fixed) | 3.3V |
| VoltageDropout(Max) | 0.2V @ 100mA |
| Current-Output | 1A |
| ProtectionFeatures | Over Temperature, Short Circuit |
| OperatingTemperature | -40°C ~ 125°C |
| MountingType | Surface Mount |
| Package/Case | TO-263-4, D²Pak (3 Leads + Tab), TO-263AA |
概要
Description
LM3940IS-3.3 is a fixed 3.3 V low‑dropout (LDO) voltage regulator from TI’s LM3940 family. It provides a stable 3.3 V output from a higher input voltage with low dropout and simple three‑terminal operation (input, ground, output). Key points:
- Fixed output: 3.3 V
- Low dropout suitable for battery/applications where headroom is tight
- Protection features commonly included: thermal/shutdown protection and current limiting
- Requires external capacitors for stability (input and output capacitors per datasheet)
- Output current capability depends on package (typical ranges from a few hundred mA up to around 1 A in higher‑grade packages)
- Packaging suffix IS denotes a particular surface‑mount package variant
Typical uses: microcontroller and digital logic rails, embedded systems, and any 3.3 V supply derived from a higher voltage.
For exact electrical specs (max input, dropout at a given current, quiescent current, required capacitor values, pinout by package), refer to the official datasheet for the specific IS package variant.
- Fixed output: 3.3 V
- Low dropout suitable for battery/applications where headroom is tight
- Protection features commonly included: thermal/shutdown protection and current limiting
- Requires external capacitors for stability (input and output capacitors per datasheet)
- Output current capability depends on package (typical ranges from a few hundred mA up to around 1 A in higher‑grade packages)
- Packaging suffix IS denotes a particular surface‑mount package variant
Typical uses: microcontroller and digital logic rails, embedded systems, and any 3.3 V supply derived from a higher voltage.
For exact electrical specs (max input, dropout at a given current, quiescent current, required capacitor values, pinout by package), refer to the official datasheet for the specific IS package variant.
Equivalent
Equivalent regulators to LM3940IS-3.3 include:
- AMS1117-3.3
- LM1117-3.3
- LD1117V33 (ST)
- NCP1117-3.3 (OnSemi)
- TLV1117-3.3 (TI)
- MCP1700-33 (Microchip)
Note: pinout/footprint can differ; verify datasheets and footprints before replacement.
- AMS1117-3.3
- LM1117-3.3
- LD1117V33 (ST)
- NCP1117-3.3 (OnSemi)
- TLV1117-3.3 (TI)
- MCP1700-33 (Microchip)
Note: pinout/footprint can differ; verify datasheets and footprints before replacement.
Features
LM3940IS-3.3 features (fixed 3.3 V LDO):
- Fixed output: 3.3 V
- Output current: up to 1 A
- Low dropout: approx. 0.5 V at 1 A (typical)
- Wide input range: up to ~26 V (suitable for automotive use)
- Protection: thermal shutdown and current limiting
- Stability: requires an output capacitor (low-ESR, typically around 10 µF)
- Packaging: available in surface-mount/is‑style packages for compact designs
Note: Always check the specific datasheet for exact electrical specs and recommended capacitors.
- Fixed output: 3.3 V
- Output current: up to 1 A
- Low dropout: approx. 0.5 V at 1 A (typical)
- Wide input range: up to ~26 V (suitable for automotive use)
- Protection: thermal shutdown and current limiting
- Stability: requires an output capacitor (low-ESR, typically around 10 µF)
- Packaging: available in surface-mount/is‑style packages for compact designs
Note: Always check the specific datasheet for exact electrical specs and recommended capacitors.
Pinout
3 pins. It’s a fixed 3.3V low-dropout regulator (VIN -> GND -> VOUT). Pin 1 = GND, Pin 2 = VOUT (3.3V), Pin 3 = VIN.
Manufacturer
- Manufacturer: Texas Instruments (TI).
- About the company: TI is an American multinational technology company that designs and manufactures semiconductors and related components, focusing on analog, mixed-signal, and embedded processing products.
- About the company: TI is an American multinational technology company that designs and manufactures semiconductors and related components, focusing on analog, mixed-signal, and embedded processing products.
Application
LM3940IS-3.3 is a fixed 3.3V low-dropout regulator. Typical application areas:
- Automotive electronics (12–24V systems, transient tolerance)
- Industrial and embedded systems requiring a 3.3V rail
- Microcontrollers, DSPs, FPGAs, memories, and other digital ICs
- Sensor/actuator interfaces and data-acquisition modules
- Communication modules (CAN, USB, Ethernet PHY)
- Portable/consumer devices deriving 3.3V from higher voltage rails
Used anywhere a simple, reliable 3.3V supply is needed from a higher input voltage.
- Automotive electronics (12–24V systems, transient tolerance)
- Industrial and embedded systems requiring a 3.3V rail
- Microcontrollers, DSPs, FPGAs, memories, and other digital ICs
- Sensor/actuator interfaces and data-acquisition modules
- Communication modules (CAN, USB, Ethernet PHY)
- Portable/consumer devices deriving 3.3V from higher voltage rails
Used anywhere a simple, reliable 3.3V supply is needed from a higher input voltage.
Package
LM3940IS-3.3 comes in a 3-pin SOT-23 plastic surface-mount package (SC‑70 style).
