Power Electronics

High-Current Members of the Ripple Blocker Family of LDOs and Load Switches

Micrel, Inc. announced availability of four new products that incorporate Micrel's proprietary Ripple Blocker™ technology that was launched in the first quarter of 2012. The MIC94305 and the MIC94325/45/55family support more than twice the output current load offered by previously released 200mA Ripple Blocker products with the same ground-breaking, highly efficient noise suppression for today's highly sensitive data and image capturing systems. The Ripple Blocker family is ideal for today's most demanding portable applications including smart phones, tablets, notebooks/webcams, digital still and video cameras, GPS, mobile computing and automotive and industrial applications. The MIC94305/25/45/55are currently available in volume with pricing starting at $0.31 for 1K quantities.

These new high-current LDO linear voltage regulators provide low-frequency ripple attenuation (switching noise rejection) to a regulated output voltage - essential for applications where a DC-to-DC switching converter is required, but where switching noise cannot be tolerated by sensitive downstream circuits. Adding Ripple Blocker LDO regulators after the DC-to-DC converters provides power supply ripple rejection (PSRR) with input voltages operating near the output voltage level, which improves overall system efficiency. The essential difference with these new devices lies in their ability to support higher output current loads - a requirement that has become increasingly important for CMOS Sensors in digital still cameras, security cameras and rear view camera for automotive applications.

Micrel's Ripple Blocker technology improves minimum detectable signal capturing for low-light image sensors by suppressing system power ripple for the Image System Processor (ISP). By eliminating the large LC filter that would typically be required to reduce ripple in a discrete solution, the devices provide more usable board space to accommodate space-constrained designs. In addition, this new series offers an operating input range of 1.8V to 3.6V with exceptional transient performance, ultra-low dropout and very high PSRR (80db @ 1KHz).

The new devices deliver up to 500mA output current and active noise rejection over a wide frequency band: >50dB from 10Hz to 5MHz at a 500mA load. The MIC943x5 options include a 500mA load switch MIC94305, two fixed output LDOs (MIC94345/55) or adjustable output voltage (MIC94325). The MIC94355 version offers an auto-discharge to discharge the output capacitor when the part is disabled. All versions offer current-limit and thermal-limit protection. The devices also feature a -40ºC to +125ºC junction temperature range. Package options include 0.84mm x 1.32mm, 6-bump CSP and the 1.6mm x 1.6mm Thin DFN package.

Micrel Inc.
Part Number: MIC94305

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