Overview
The LM217T-DG, produced by STMicroelectronics, is a monolithic integrated circuit designed as a positive adjustable voltage regulator. It is available in the TO-220 package and is part of the LM217 and LM317 series. 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 device features a floating operation, making it suitable for regulating high voltage supplies relative to ground, as long as the maximum input-to-output differential voltage is not exceeded.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Output Voltage Range | 1.2 to 37 | V |
| Output Current | Internally limited, up to 1.5 A | A |
| Line Regulation | 0.01 to 0.07 %/V | %/V |
| Load Regulation | 5 to 70 mV (VO ≤ 5 V), 0.1 to 1.5 % (VO ≥ 5 V) | mV, % |
| Adjustment Pin Current | 50 to 100 µA | µA |
| Reference Voltage | 1.2 to 1.3 V | V |
| Operating Junction Temperature | -25 to 150 °C | °C |
| Thermal Resistance Junction-Ambient | 50 °C/W (TO-220FP) | °C/W |
| Power Dissipation | Internally limited | W |
| Storage Temperature | -65 to 150 °C | °C |
Key Features
- Adjustable Output Voltage: The output voltage can be adjusted over a range of 1.2 to 37 V using an external resistor divider.
- High Current Capability: Capable of supplying more than 1.5 A of load current.
- Precision Regulation: Features 0.1% line and load regulation, ensuring stable output voltage.
- Protection Features: Includes current limiting, thermal shutdown, and SOA (Safe Operating Area) control for enhanced reliability.
- Floating Operation: Allows regulation of high voltage supplies relative to ground.
- Low Adjustment Pin Current: The adjustment pin current is minimized and remains constant with line and load changes.
- Improved Ripple Rejection: Enhanced by adding capacitors between the adjustment terminal and ground.
Applications
- Voltage Regulation: Suitable for various voltage regulation applications requiring adjustable output voltages.
- Current Regulation: Can be used as a precision current regulator by connecting a fixed resistor between the adjustment and output terminals.
- Battery Charging: Can be configured for battery charging applications with adjustable charging rates.
- Electronic Shutdown Regulators: Can be used in electronic shutdown regulators for system protection.
- High Voltage Supplies: Ideal for regulating high voltage supplies relative to ground.
Q & A
- What is the output voltage range of the LM217T-DG?
The output voltage range is adjustable from 1.2 to 37 V.
- What is the maximum output current of the LM217T-DG?
The maximum output current is internally limited, but it can supply more than 1.5 A.
- What are the key protection features of the LM217T-DG?
The device includes current limiting, thermal shutdown, and SOA control.
- How is the output voltage adjusted in the LM217T-DG?
The output voltage is adjusted using an external resistor divider connected to the adjustment pin.
- What is the operating junction temperature range of the LM217T-DG?
The operating junction temperature range is -25 to 150 °C.
- What are the recommended external capacitors for improved performance?
An input bypass capacitor of 0.1 µF, an adjustment terminal to ground 10 µF capacitor, and an output capacitor of 1 µF tantalum or 25 µF aluminum electrolytic are recommended.
- Can the LM217T-DG be used as a current regulator?
- What is the purpose of the adjustment pin current in the LM217T-DG?
The adjustment pin current is minimized and remains constant with line and load changes, ensuring stable output voltage regulation.
- How does the LM217T-DG protect against input and output short circuits?
Protection diodes (D1 and D2) can be added to protect against input short circuits and output short circuits for capacitor discharging.
- What are some common applications of the LM217T-DG?
Common applications include voltage regulation, current regulation, battery charging, electronic shutdown regulators, and high voltage supplies.
