Designed for input voltages up to 61 V, the A7987 can be operated in conventional automobiles as well as hybrid and electric vehicles on the 24 V vehicle electrical system and reliably regulates the output voltage when disturbing events such as load shedding occur. The output voltage can be set to values from 0.8 V to the input voltage with a low dropout voltage. The load current of up to 3 A supports a wide range of loads from logic circuits to lighting.
The current limit and switching frequency of up to 1.5 MHz are set using external pull-down resistors, enabling designers to create compact power supply modules with optimized output inductance dimensions. Pulse current measurement with digital frequency foldback minimizes power component stress and improves reliability. Built-in overheat protection with shutdown and auto recovery minimizes dependency on external intervention.
The A7987 incorporates a low-resistance N-channel power MOSFET. At low load, pulse skipping maintains output control. A bias voltage input with integrated switching also allows analog circuits to be powered from an external source for optimum efficiency.
A synchronization connector allows up to five controllers to be used together in phase-shifted operation to avoid interference and reduce the rms current in the input capacitor. An enable connection and a power-good indicator with adjustable delay can be used for sequencing the controllers. The inrush current can also be reduced with the additional adjustable softstart function.
The A7987, certified according to AEC-Q100, is already in series production. It is available in a 5 mm x 6.4 mm HTSSOP16 package in exposed pad design at prices starting at 2 US dollars (from 1,000 units).
ST also offers the Evaluation Board STEVAL-ISA207V1 for the realization of new projects with the A7987, which is available immediately at www.st.com or from distributors.