STMicroelectronics has announced two automotive-qualified step-down synchronous DC/DC converters. The A6983 and A69831 converters address a range of automotive applications, including body electronics, audio systems and inverter gate drivers.
(Source: STMicroelectronics)
The new devices include the A6983 converters, comprised of six non-isolated step-down converters in low-consumption and low-noise configurations, and the A6983I isolated buck converter. On-chip compensation circuitry provides highly integrated monolithic devices that need minimal external components including filtering, feedback and a transformer with the A6983I, saving space and easing integration.
The non-isolated A6983 converters deliver up to 3-A load current and achieve 88% typical efficiency at full load. Low-consumption variants (A6983C) are optimized for light-load operation, featuring high efficiency and low output ripple, minimizing battery drain on the vehicle battery for active applications when the vehicles are parked. The low-noise A6983N variants use a constant switching frequency and minimize output ripple across the load range for applications such as audio-system power supplies. Both offer a choice of 3.3 V, 5.0 V and adjustable output voltage from 0.85 V to VIN.
The A6983I 10-W iso-buck converter with primary-side regulation eliminates the need for an optocoupler. It allows accurate adjustment of the primary output voltage, and the transformer turns ratio determines the secondary voltage. These are suited for use as an isolated gate driver for IGBTs or silicon-carbide (SiC) MOSFETs in traction inverters and on-board chargers (OBCs).
The isolated and non-isolated variants feature a low quiescent operating current of 25 µA and a power-saving shutdown mode drawing less than 2 µA. The input-voltage range from 3.5 V to 38 V and load-dump tolerance up to 40 V prevent disruption due to transients on the main supply bus, ST said.
Other features include output overvoltage protection, thermal protection and internal soft start. Optional spread-spectrum operation aids in lowering electromagnetic interference in noise-sensitive applications. They are qualified to AEC-Q100 Grade 1 requirements.
The converters are housed in a 3 × 3-mm QFN16 package. Pricing starts at $1.75 for the A6983 and $1.81 for the A6983I, both in quantities of 1,000. Free samples of the A6983 and A6983I are available from the ST eStore. The STEVAL-A6983CV1 and STEVAL-A6983NV1 evaluation boards for the A6983 and STEVAL-L6983IV for the A6983I are also available.
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