Summary of STMICROELECTRONICS L7983 STEP-DOWN SWITCHING REGULATOR
Summary: The L7983 is a monolithic step-down switching regulator delivering up to 300 mA with peak current mode control. It supports input voltages from 3.5 V to 60 V, offers fixed (3.3 V, 5 V) or adjustable output (0.85 V to VIN), and features selectable Low Consumption Mode (LCM) and Low Noise Mode (LNM). It includes programmable switching frequency, internal protections, UVLO, soft-start, optional spread-spectrum, synchronization, and low quiescent/shutdown currents for industrial bus applications.
Parts used in the L7983 Step-Down Switching Regulator Project:
- L7983 step-down switching regulator (monolithic IC)
- Input supply (3.5 V to 60 V source)
- Output capacitor(s)
- Inductor for switching regulator
- Feedback resistors for adjustable output (if used)
- Enable/UVLO resistor network (for adjustable UVLO)
- Optional external clock for synchronization
- Optional components for spread-spectrum (dithering) implementation
- PCB and thermal management components (heat dissipation)
The L7983 device is a step-down monolithic switching regulator able to deliver up to 300 mA DC based on peak current mode architecture. The output voltage adjustability ranges from 0.85 V to VIN. The wide input voltage range and adjustable UVLO threshold meet the specification for the 12 V, 24 V, and 48 V industrial bus standards.
The “Low Consumption Mode” (LCM) is designed for applications active during idle mode, so it maximizes the efficiency at light load with a controlled output voltage ripple. The “Low Noise Mode” (LNM) makes the switching frequency constant, meeting the low noise application specification.
Key Features
- 3.5 V to 60 V operating input voltage
- Fixed output voltage (3.3 V and 5 V) or adjustable from 0.85 V to VIN
- 300 mA DC output current
- Dynamic low consumption mode to low noise mode selection
Additional Features
- 3.5 V to 60 V operating input voltage
- Fixed output voltage (3.3 V and 5 V) or adjustable from 0.85 V to VIN
- 300 mA DC output current
- Dynamic Low Consumption Mode (LCM) to Low Noise Mode (LNM) selection
- 10 µA operating quiescent current (L7983PU33R, VIN > 24 V, LCM)
- 2.3 µA shutdown current
- 200 kHz to 2.2 MHz programmable switching frequency
- Optional spread-spectrum (dithering)
- Internal soft-start
- Enable/adjustable UVLO threshold
- Synchronization to an external clock
- Internal compensation network
- Internal current limiting
- Overvoltage protection
- Output voltage sequencing
- Thermal shutdown
Read more: STMICROELECTRONICS L7983 STEP-DOWN SWITCHING REGULATOR
- What input voltage range does the L7983 support?
The L7983 supports an input voltage range from 3.5 V to 60 V. - What output voltages are available with the L7983?
The L7983 is available with fixed outputs of 3.3 V and 5 V or an adjustable output from 0.85 V to VIN. - How much output current can the L7983 deliver?
The device can deliver up to 300 mA DC output current. - What modes optimize efficiency or low noise in the L7983?
It has Low Consumption Mode (LCM) to maximize light-load efficiency and Low Noise Mode (LNM) to maintain constant switching frequency for low noise. - Is the switching frequency programmable on the L7983?
Yes, the switching frequency is programmable from 200 kHz to 2.2 MHz. - Does the L7983 include protection features?
Yes, it includes internal current limiting, overvoltage protection, output voltage sequencing, and thermal shutdown. - Can the L7983 synchronize to an external clock?
Yes, the device supports synchronization to an external clock. - What are the quiescent and shutdown currents for the L7983?
The device has 10 µA operating quiescent current (example L7983PU33R, VIN > 24 V, LCM) and 2.3 µA shutdown current. - Does the L7983 have soft-start and UVLO features?
Yes, it includes an internal soft-start and an enable/adjustable undervoltage lockout (UVLO) threshold.
