Easy-to-use and compact point-of-load power suppliesare necessary in systems with widely distributed, highcurrent, low Voltage loads. The LTC®3415 provides acompact, simple and versatile solution. It includes a pairof integrated complementary power MOSFETs (32mΩtop and 25mΩ bottom) and requires no external senseresistor. A complete design requires an inductor andinput/output capacitors, and that’s it. The result is a fast,constant frequency, 7A current mode DC/DC switchingregulator.
Low power standby requirements are typically associatedwith battery-powered systems. Automotive systems,for example, commonly require power supplies tomaintain output Voltage regulation even under no-loadconditions—while drawing minimal quiescent current topreserve battery life. Rising energy costs, however, haveextended the need for low current standby operation toline-powered systems, such as small plugged-in appliancesfor home and business.
Many complex systems—such as telecom equipment,memory modules, optical systems, networking equipment,servers and base stations—use FPGAs and otherdigital ICs that require multiple Voltage rails that muststart up and shut down in a specific order, otherwise theICs can be damaged. The LTC®2924 is a simple andcompact solution to power supply sequencing in a 16-pinSSOP package (see Figures 1 and 2).
Automobile electronic systems place high demands ontoday’s DC/DC converters. They must be able to preciselyregulate an output Voltage in the face of wide temperatureand input Voltage ranges—including load dump transientsin excess of 60V and cold crank Voltage drops to 4V. Theconverter must also be able to minimize battery drain inalways-on systems by maintaining high effi ciency over abroad load current range. Similar demands are made bymany 48V nonisolated telecom applications, 40V FireWireperipherals and battery-powered applications with autoplug adaptors. The LT3437’s best in classperformancemeets all of these requirements in a small thermallyenhanced 3mm × 3mm DFN package.
Battery powered applications that have a signifi cantamount of time in standby mode, require electrical circuitsto operate with a low quiescent current to preserve batterylife. The LTC3835 synchronous step-down controlleris an excellent solution with its ultralow quiescent current(80μA). Other features make it uniquely qualifi ed tosatisfy the needs of automotive applications. A wide 4Vto 36V input Voltage range protects the supply againsthigh input Voltage transients and is compatible with lowVoltage cold crank conditions. The constant frequencycurrent-mode architecture with high-side inductor current
Traditionally, an Electronic Circuit Breaker (ECB) comprisesa MOSFET, a MOSFET controller and a current senseresistor. The LTC®4213 does away with the sense resistorby using the RDS(ON) of the external MOSFET. The resultis a simple, small solution that offers a signifi cant lowinsertion loss advantage at low operating load Voltage.The LTC4213 features two circuit breaking responses tovarying overload conditions with three selectable tripthresholds and a high side drive for an external N-channelMOSFET switch.
A number of conventional solutions have been available forthe design of a DC/DC converter where the output Voltageis within the input Voltage range—a common scenarioin Li-Ion battery-powered applications—but none werevery attractive until now. Conventional topologies, suchas SEPIC or boost followed by buck, have numerousdisadvantages, including low effi ciency, complex magnetics,polarity inversion and/or circuit complexity/cost. TheLTC®3785 buck-boost controller yields a simple, effi cient,low parts-count, single-converter solution that is easyto implement, thus avoiding the drawbacks associatedwith traditional solutions.
Video cable driver amplifi er output stages traditionallyrequire a supply Voltage of at least 6V in order to providethe required output swing. This requirement is usuallymet with 5V supplies by adding a boost regulator or asmall local negative rail, say via the popular LT®1983-3.Such additional circuitry is unnecessary in typical 1VP-Pvideo connections, such as HD component video, if thecable driver amplifi ers simply offer near rail-to-rail outputcapability when powered from 5V.
Automotive batteries, industrial power supplies, distributedsupplies and wall transformers are all sources ofwide-ranging high Voltage inputs. The easiest way to stepdown these sources is with a high Voltage monolithicstep-down regulator that can directly accept a wide inputrange and produce a well-regulated output. The LT®3493accepts inputs from 3.6V to 36V and LT3481 acceptsinputs from 3.6V to 34V. Both provide excellent lineand load regulation and dynamic response. The LT3481offers a high effi ciency solution over a wide load range andkeeps the output ripple low during Burst Mode® operationwhile the LT3493 provides a tiny solution with minimalexternal components. The LT3493 operates at 750kHzand the LT3481 has adjustable frequency from 300kHzto 2.8MHz. High frequency operation enables the use ofsmall, low cost inductors and ceramic capacitors.
Speed and accuracy don’t always go hand-in-handin DC/DC converter systems—that is, until now. TheLTC3811 is a dual output, fi xed frequency current modeDC/DC switching regulator controller designed for one oftoday’s most demanding power supply applications: highcurrent, low Voltage processor core supplies.
