Compact Buck-Boost Regulators with Ultra-Fast Switching
Portable Design News, Monday September 01, 2008
Analog Devices has announced a compact buck-boost regulator, the first to support switching frequencies at speeds up to 2.5 MHz. ADI’s ADP2503 and ADP2504 step-up/step-down dc-to-dc regulators are designed to regulate voltages in portable devices for RF, audio and motor applications.
The ADP2503 and ADP2504 operate at input voltages ranging from 2.3 V and 5.5 V, which meets the requirements for single Li-Ion, Li-Ion polymer cell and multiple alkaline/NiMH cell applications. Fixed output voltages range from 2.8 V to 5 V. 
The ultra-fast switching speed of the new regulators allows designers to use low-cost multilayer inductors that are half the size of other solutions. In addition, the total external component count has been reduced to three, resulting in a total PCB area of less than 13 mm2 and a height of less than 1 mm, making the solution ideal for space constrained applications such as wireless handsets, digital still cameras, portable audio players and USB-powered consumer and industrial devices.
The ADP2503 and ADP2504 regulators are based on ADI’s new proprietary current-mode buck-boost architecture, achieving glitchless mode transitions and outstanding transient performance across line and load. This high level of output stability is critical for powering sensitive analog and digital circuitry. The devices also feature one of the industry’s lowest no-load quiescent current (Iq) levels—38 µA in power-save mode—which extends stand-by time in portable electronics and/or increases the power budget for the inclusion of additional features. The proprietary H-Bridge buck-boost architecture improves the efficiency by more than 10 percent versus legacy cascaded boost-buck architectures by reducing switching losses.
The ADP2503 and ADP2504 are available now in sample quantities and come housed in a 10-lead 3-mm × 3-mm thin LFCSP package. The buck-boost regulators are priced at $1.40 per unit in 1,000-unit quantities.
Analog Devices, Norwood, MA (781) 329-4700 [http://www.analog.com]
