Overview
The LM317BT, produced by STMicroelectronics, is a monolithic integrated circuit designed as a positive adjustable voltage regulator. It is part of the LM317 series, which includes various package options such as TO-220, TO-220FP, D²PAK, and SOT223. This regulator is capable of supplying more than 1.5 A of load current with an output voltage adjustable over a range of 1.2 to 37 V. The output voltage is easily set using a resistive divider, making it highly versatile and eliminating the need for multiple fixed regulators.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Output Voltage Range | 1.2 to 37 V | V |
| Output Current | Greater than 1.5 A | A |
| Line Regulation | 0.01% (typical) | %/V |
| Load Regulation | 0.1% (typical) | % |
| Input-Output Differential Voltage | Up to 40 V | V |
| Operating Junction Temperature | 0 to 125 °C | °C |
| Thermal Resistance (Junction-Ambient) | 50 °C/W (TO-220) | °C/W |
| Package | TO-220 | |
| RoHS Compliance Grade | Ecopack2 |
Key Features
- Output voltage range adjustable from 1.2 to 37 V
- Output current greater than 1.5 A
- 0.1% line and load regulation
- Floating operation for high voltages
- Complete series of protections: current limiting, thermal shutdown, and safe operating area (SOA) control
- Internal reference voltage of 1.25 V between the output and adjustment terminals
- Optional use as a precision current regulator by connecting a fixed resistor between the adjustment and output terminals
Applications
- Industrial control systems
- Desktop PCs and digital signage
- Motor controls: brushed DC, brushless DC, low-voltage, permanent magnet, and stepper motors
- Power bank solutions and power over ethernet (PoE)
- Programmable logic controllers and RFID readers
- High-speed data acquisition and generation
- Electronic shelf labels and HVAC systems
Q & A
- What is the output voltage range of the LM317BT?
The output voltage range of the LM317BT is adjustable from 1.2 to 37 V.
- What is the maximum output current of the LM317BT?
The LM317BT can supply more than 1.5 A of load current.
- What type of protections does the LM317BT include?
The LM317BT includes current limiting, thermal shutdown, and safe operating area (SOA) control.
- How is the output voltage set on the LM317BT?
The output voltage is set using a resistive divider connected to the adjustment terminal.
- What is the operating junction temperature range for the LM317BT?
The operating junction temperature range for the LM317BT is from 0 to 125 °C.
- Can the LM317BT be used as a precision current regulator?
Yes, the LM317BT can be used as a precision current regulator by connecting a fixed resistor between the adjustment and output terminals.
- What is the thermal resistance (junction-ambient) for the TO-220 package of the LM317BT?
The thermal resistance (junction-ambient) for the TO-220 package is 50 °C/W.
- Is the LM317BT RoHS compliant?
Yes, the LM317BT is RoHS compliant with an Ecopack2 grade.
- What are some common applications of the LM317BT?
Common applications include industrial control systems, desktop PCs, motor controls, power bank solutions, and programmable logic controllers.
- How can the ripple rejection of the LM317BT be improved?
The ripple rejection can be improved by adding a capacitor between the adjustment terminal and ground, and by using an input bypass capacitor and an output capacitor.
