Overview
The L78L series of three-terminal positive regulators, including the L78L15ABD model from STMicroelectronics, are designed to provide reliable and efficient voltage regulation. These regulators are essentially indestructible due to their internal current limiting and thermal shutdown features. With adequate heat-sinking, they can deliver up to 100 mA of output current, making them suitable for a wide range of applications. They are intended for fixed voltage regulation, local or on-card regulation, and can also be used with power pass elements to create high-current voltage regulators. The L78L series offers improvements over traditional Zener diode/resistor combinations, including lower quiescent current and reduced noise.
Key Specifications
| Parameter | Test Conditions | Min. | Typ. | Max. | Unit |
|---|---|---|---|---|---|
| Output Voltage (VO) | TJ = 25°C | 13.8 | 15 | 16.2 | V |
| Output Voltage (VO) | IO = 1 to 40 mA, VI = 17.5 to 30 V | 13.5 | 15 | 16.5 | V |
| Line Regulation (∆VO) | VI = 17.5 to 30 V, TJ = 25°C | 300 | mV | ||
| Load Regulation (∆VO) | IO = 1 to 100 mA, TJ = 25°C | 80 | mV | ||
| Quiescent Current (Id) | TJ = 25°C | 6 | mA | ||
| Dropout Voltage (Vd) | 1.7 | V |
Key Features
- Output current up to 100 mA
- Output voltages of 3.3, 5, 6, 8, 9, 10, 12, 15, 18, 24 V
- Thermal overload protection
- Short-circuit protection
- No external components required
- Available in either ± 4% (A) or ± 8% (C) selection
Applications
The L78L series, including the L78L15ABD, is suitable for a variety of applications, including:
- Fixed voltage regulation
- Local or on-card regulation to eliminate noise and distribution problems associated with single-point regulation
- Use with power pass elements to create high-current voltage regulators
- Replacement for Zener diode/resistor combinations, offering lower quiescent current and reduced noise
Q & A
- What is the maximum output current of the L78L15ABD?
The maximum output current of the L78L15ABD is up to 100 mA.
- What are the available output voltages for the L78L series?
The L78L series offers output voltages of 3.3, 5, 6, 8, 9, 10, 12, 15, 18, and 24 V.
- Does the L78L15ABD require external components?
No, the L78L15ABD does not require external components.
- What kind of protection does the L78L15ABD have?
The L78L15ABD has thermal overload protection and short-circuit protection.
- What is the quiescent current of the L78L15ABD at 25°C?
The quiescent current of the L78L15ABD at 25°C is typically 6 mA.
- What is the dropout voltage of the L78L15ABD?
The dropout voltage of the L78L15ABD is 1.7 V.
- Can the L78L15ABD be used in high-current applications?
Yes, the L78L15ABD can be used with power pass elements to create high-current voltage regulators.
- What is the operating temperature range of the L78L15ABD?
The operating temperature range of the L78L15ABD is from 0 to 125°C.
- Is the L78L15ABD still in production?
No, the L78L15ABD is obsolete and no longer manufactured.
- What are some recommended substitutes for the L78L15ABD?
Recommended substitutes include the LM78L15ACM/NOPB from Texas Instruments.
