Overview
The L4978 is a step-down monolithic power switching regulator produced by STMicroelectronics. It delivers up to 2A of current at output voltages adjustable between 3.3V and 50V, selected by a simple external divider. Realized in BCD mixed technology, the device utilizes an internal power D-MOS transistor with a typical Rds(on) of 0.25Ω, ensuring high efficiency and high switching speed. The regulator operates with an input voltage range of 8V to 55V and supports switching frequencies up to 300kHz, making it suitable for a wide range of applications.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Input Voltage Range | 8V | 55V | V | |
| Output Voltage Range | 3.3V | 50V | V | |
| Output Current | 2A | A | ||
| Switching Frequency | up to 300kHz | kHz | ||
| Internal Reference Voltage | 3.33V | 3.36V | 3.35V | V |
| Quiescent Current | 2.5mA | 3.5mA | mA | |
| Thermal Shutdown | -40°C to 150°C | °C | ||
| Package Types | DIP-8, SO16W |
Key Features
- Pulse-by-pulse current limit and hiccup mode for short circuit protection
- Voltage feedforward regulation
- Soft-start function
- Protection against feedback loop disconnection
- Inhibit for zero current consumption
- Thermal shutdown
- Zero load current operation
- Precise 3.3V (±1%) internal reference voltage
- Adjustable switching frequency up to 300kHz
Applications
The L4978 is suitable for a variety of applications, including industrial and automotive systems, due to its high reliability and performance. It is particularly useful in scenarios requiring efficient step-down voltage regulation with a wide input voltage range and adjustable output voltages.
Q & A
- What is the output current capability of the L4978? The L4978 can deliver up to 2A of output current.
- What is the input voltage range of the L4978? The input voltage range is from 8V to 55V.
- How is the output voltage adjusted on the L4978? The output voltage is adjustable from 3.3V to 50V using a simple external divider.
- What is the maximum switching frequency of the L4978? The switching frequency can be adjusted up to 300kHz.
- Does the L4978 have thermal shutdown protection? Yes, it includes thermal shutdown protection.
- What are the package options for the L4978? The device is available in DIP-8 and SO16W packages.
- Does the L4978 support soft-start functionality? Yes, it includes a soft-start function.
- How does the L4978 protect against short circuits? It uses pulse-by-pulse current limit and hiccup mode for short circuit protection.
- Is the L4978 suitable for zero current consumption? Yes, it has an inhibit feature for zero current consumption.
- What is the internal reference voltage of the L4978? The internal reference voltage is 3.3V (±1%).
