New Voltage-Mode PWM Controller For HDDs

Microsemi says that its new LX1684 controller is a switching regulator that has a high-efficiency synchronous driver and is optimized to provide 12V to 3.3V or 12V to 2.5V regulation. It also can convert 5V or 3.3V to voltages as low as 1.25V. Typical applications for the chip include low-cost buck (step-down) regulators, hard disk drives and computer add-on cards. Its switching frequency is fixed at 175kHz, which is intended to save space and allow short-circuit current limiting without the use of current sense resistors. The LX1684's constant frequency voltage-mode control requires no external compensation. The LX1684 is supplied in a 14-pin SOIC plastic package with a 10K-piece unit price of $0.89 and is available now.