Overview
The LM1086ISX-3.3 is a low dropout positive voltage regulator produced by National Semiconductor, now part of Texas Instruments. This regulator is known for its high performance and versatility, offering a maximum dropout of 1.5 V at a load current of 1.5 A. It shares the same pin-out as the industry standard LM317, making it a compatible replacement in many applications. The LM1086ISX-3.3 is specifically configured to provide a fixed output voltage of 3.3 V, with integrated adjust resistors for simplicity.
Key Specifications
| Parameter | Value |
|---|---|
| Output Voltage | 3.3 V (Fixed) |
| Maximum Input Voltage | 18 V |
| Output Current | 1.5 A |
| Maximum Dropout Voltage | 1.5 V at 1.5 A |
| Line Regulation | 0.015% (Typical) |
| Load Regulation | 0.1% (Typical) |
| Ripple Rejection | 60 dB at 120 Hz, COUT = 25 µF Tantalum, IOUT = 1.5 A |
| Operating Temperature Range | -40°C to 125°C |
| Thermal Resistance (Junction-to-Case) | 1.5°C/W (TO-263) |
| Package Type | TO-263 (KTT) |
| Pins | 3 |
Key Features
- Available in fixed output voltages (including 3.3 V) and adjustable versions
- Current limiting and thermal protection
- 2% output accuracy
- High efficiency linear regulator
- Stable with ceramic output capacitors with appropriate ESR
- Zener trimmed bandgap reference
- No input capacitor required unless the device is more than 6 inches from the input filter capacitors
- Can be used as a precision current regulator by connecting a fixed resistor between the adjustment pin and output
Applications
- SCSI-2 Active Terminator
- Battery Charger
- Post Regulation for Switching Supplies
- Microprocessor Supply
- Constant Current Regulator
- High Efficiency Linear Regulators
Q & A
- What is the maximum dropout voltage of the LM1086ISX-3.3? The maximum dropout voltage is 1.5 V at a load current of 1.5 A.
- What is the output voltage of the LM1086ISX-3.3? The output voltage is fixed at 3.3 V.
- What is the maximum input voltage for the LM1086ISX-3.3? The maximum input voltage is 18 V.
- Does the LM1086ISX-3.3 require an input capacitor? Typically, no input capacitor is needed unless the device is situated more than 6 inches from the input filter capacitors.
- What is the operating temperature range of the LM1086ISX-3.3? The operating temperature range is -40°C to 125°C.
- Can the LM1086ISX-3.3 be used as a current regulator? Yes, it can be used as a precision current regulator by connecting a fixed resistor between the adjustment pin and output.
- What is the ripple rejection of the LM1086ISX-3.3? The ripple rejection is 60 dB at 120 Hz, with COUT = 25 µF Tantalum and IOUT = 1.5 A.
- What type of output capacitor is recommended for stability? The recommended output capacitor is a 10 µF tantalum or a 50 µF aluminum electrolytic capacitor.
- Does the LM1086ISX-3.3 have built-in thermal protection? Yes, it includes current limiting and thermal shutdown protection.
- What is the thermal resistance of the LM1086ISX-3.3 in the TO-263 package? The thermal resistance (junction-to-case) is 1.5°C/W.
