New automotive-qualified step-down synchronous DC/DC converters from STMicroelectronics are easier to integrate and take up less space in a variety of applications, including audio systems, inverter gate drivers, and body electronics.
The A6983 converters, which include the A6983I isolated buck converter and six non-isolated step-down converters in low-noise and low-consumption versions, provide versatile design options.
These highly integrated monolithic automotive synchronous buck converters only require a few number of external components, such as a transformer, feedback, and filtering, because they include compensation circuitry built right into the device (A6983I).
The A6983 converters offer flexible design choices, comprising six non-isolated step-down converters in low-consumption and low-noise configurations and the A6983I isolated buck converter. With compensation circuitry on-chip, these highly integrated monolithic devices need only minimal external components including filtering, feedback, and a transformer with the A6983I.
The non-isolated A6983 step-down synchronous DC/DC converters have a maximum load current supply of 3A and a typical efficiency of 88% when operating at full load. For applications that run continuously when parked, the low-consumption variations (A6983C) are designed for light-load operation with excellent efficiency and minimal output ripple.
For the best performance in applications like audio-system power supply, the low-noise A6983N variations minimize output ripple over the load range while operating at a constant switching frequency. Both varieties include a configurable output voltage range of 0.85V to VIN in addition to 3.3V and 5.0V options.
The A6983I is a primary-side regulated 10W iso-buck converter that does not need an optocoupler. This converter enables precise control of the primary output voltage, making it ideal for use as an isolated gate driver for IGBTs or silicon-carbide (SiC) MOSFETs in traction inverters and on-board chargers (OBCs). The secondary voltage is determined by the transformer turns ratio.
Every variation, whether isolated or not, features a power-saving shutdown mode that consumes less than 2µA, and a low quiescent running current of 25µA. There is no disturbance from transients on the main supply bus because of the input-voltage range of 3.5V to 38V and the load-dump tolerance of up to 40V.
In addition, there is internal soft start, heat protection, and output overvoltage protection. Furthermore, a power-good pin that permits power sequencing and optional spread-spectrum operation assist reduce electromagnetic interference (EMI) for applications that are sensitive to noise. An external clock can be synchronized with the A6983 and A6983I.
Availability, Packaging and Pricing
The converters are offered in a 3mm x 3mm QFN16 package. Pricing starts at $1.75 for the A6983 and $1.81 for the A6983I, for orders of 1000 pieces, and free samples of the A6983 and A6983I are available from the ST eStore. The STEVAL-A6983CV1 and STEVAL-A6983NV1 A6983 evaluation boards and STEVAL-L6983IV for the A6983I are available to kickstart development and accelerate project completion.
For Further Info: www.st.com/A6983-A6983I
