Low noise low ripple buck converter with integrated ferrite head filter compensation

     The Texas Instruments TPS6291x device is a high efficiency, low noise, low ripple current mode synchronous buck converter. These devices are used in noise-sensitive applications that typically use Ldos for post-regulation, such as high-speed ADCs, clock and jitter cleaners, serializers, anti-serializers, and radar applications.

     To reduce output voltage ripple, the device loop compensation is created to work with an optional second-stage ferrite bead L-C filter. Low frequency noise levels, similar to low noise Ldos, are further achieved by capacitance-filtered internal voltage reference connected to NR/SS pins. Combined with these characteristics, the output voltage ripple is less than 10µVRMS.

     The device operates at a fixed switching frequency of 2.2MHz, 1.4MHz, or 1MHz, and can be synchronized with an external clock. The optional spread spectrum modulation scheme extends the DC-DC switching frequency over a larger span, thereby reducing mixing spurious.