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STMicroelectronics L6983 Synchronous DC Converter Featuring LCM and LNM Modes

March 15, 2020 by Misha Khan

Designed by STMicroelectronics, the L6983 synchronous DC converters are highly integrated and flexible.

The L6983 DC converter is specifically designed for industrial applications to maintain up to 95% high efficiency at all loads.


Design and Construction

Designed in a QFN16 3x3 package, the L6983 synchronous DC converter help reduce circuit complexity -a key benefit for engineers. These converters are integrated into on-chip synchronous MOSFETs. L6983 synchronous DC converters can serve as monolithic step-down regulators capable of delivering up to 38V/3A DC to loads.


STMicroelectronics L6983 DC converter.

L6983 synchronous monolithic step-down regulator. Image Credit: Mouser. 


Specifications and Features

The following are key features and specifications of STMicroelectronics L6983 synchronous DC converters:



These converters have operating input voltage ranging from 3.5V to 38V and an output voltage from 0.85V to VIN. There are two fixed versions of voltages - 3.3V and 5V.



L6983 synchronous DC converters have a shutdown current of 2 μA with an operating quiescent current of 17 μA. The output current is 3A. 



High efficiency at light loads is maintained at LCM and for noise-sensitive applications, while LNM mode meets the required specifications.



L6983 synchronous DC converters are designed using QFN16 packaging.



The L6983 converters are synchronized to an external clock and enabled with an internal soft start.


A block diagram of the L6983 DC converter.

A block diagram of the L6893 step-down converter. Image Credit: STMicroelectronics.


Modes of Operation and Key Applications

The following details outline how the L6983 synchronous DC converters work, as well as some key applications:


Input Voltage

L6983 synchronous DC converters can utilise input voltage ranging from 3.5V to 38V with adjustable output voltages. This makes them a flexible and efficient solution for smart sensors, always-on devices, smart building controllers, industrial bus-powered systems (12V or 24V), battery-powered equipment, and more. 


Switching frequency

The switching frequencies of L6983 DC converters are programmable between 200 kHz and 2.2MHz. The parameters of external frequency synchronization and frequency spread–spectrum operation helps to ease out electromagnetic compatibility.


Power good output pin

L6983 DC converters come up with a power-good output pin, making them suitable for use in applications such as fault indicators, enabling logic circuitry, and power-up/power-down sequencing. 


Consumption modes

L6983 synchronous DC converters are available with the following consumption modes:

L6983 synchronous DC converters deliver an ultra-low quiescent current of 17 µA. When the load current is less than 0.6A, the converters enter into the pulse-skipping mode. Otherwise, they remain in pulse width modulation in all other states. This quality is desirable in noise-sensitive applications, and also minimises electromagnetic disturbances.


Enable/disable Functions

The L6983 DC converters contain an EN pin for their enable/disable functions. For disabling, the typical shutdown current required is 2 µA. Conversely, enabling can be triggered when the EN pin is pulled up. Once enabled, an internal 1.3 ms soft-start takes place.


High Power Load Synchronous DC Converters

Designed for sensors, always-on applications, decentralized intelligent nodes and more, STMicroelectronics' L6983 synchronous DC converters offer high flexibility and efficiency. Specifically developed for industrial applications, these synchronous DC converters are simple to use and embedded into monolithic step-down regulators.

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