Analog Devices Inc./Maxim Integrated

The LT1301 is a micropower step-up DC/DC converter that utilizes Burst Mode™operation. The device can deliver 5V or 12V from a two-cell battery input. It features programmable 5V or 12V output via a logic-controlled input, no-load quiescent current of 120µA and a shutdown pin which reduces supply current to 10µA. The on-chip power switch has a low 170mV saturation voltage at a switch current of 1A, a four-fold reduction over prior designs. A 155kHz internal oscillator allows the use of extremely small surface mount inductors and capacitors. Operation is guaranteed at 1.8V input. This allows more energy to be extracted from the battery, increasing operating life. The ILIMpin can be used for soft start or to program peak switch current with a single resistor allowing the use of even smaller inductors in lighter load applications. The LT1301 is available in an 8-lead SOIC package, minimizing board space requirements. For a selectable 3.3V/5V step-up converter, please see the LT1300. For higher output power, see the LT1302.ApplicationsFlash Memory VPPGeneratorPalmtop ComputersPortable InstrumentsBar-Code ScannersPersonal Digital AssistantsPCMCIA Cards

The LT1302/LT1302-5 are micropower step-up DC/DC converters that maintain high efficiency over a wide range of output current. They operate from a supply voltage as low as 2V and feature automatic shifting between Burst Mode operation at light load, and current mode operation at heavy load.The internal low loss NPN power switch can handle current in excess of 2A and switch at frequencies up to 400kHz. Quiescent current is just 200µA and can be further reduced to 15µA in shutdown.Available in 8-pin PDIPor 8-pin SO packaging, the LT1302/LT1302-5 have the highest switch current rating of any similarly packaged switching regulators presently on the market.ApplicationsNotebook and Palmtop ComputersPortable InstrumentsPersonal Digital AssistantsCellular TelephonesFlash Memory

The LT1305 is a micropower step-up DC/DC converter that uses Burst Mode™operation. Similar to the LT1303, the LT1305 features a 2A internal low-loss switch and can deliver up to four times the output power of the LT1303.Quiescent current is only 120µA and the Shutdown pin further reduces current to 10µA. A low-battery detector provides an open-collector output that goes low when the input voltage drops below a preset level. The LT1305 is available in an 8-pin SO, easing board space requirements.Applications2-Cell and 3-Cell to 5V ConversionEL Panel DriversPortable Instruments

The LT1307/LT1307B are micropower, fixed frequency DC/DC converters that operate from an input voltage as low as 1V. First in the industry to achieve true current mode PWM performance from a single cell supply, the LT1307 features automatic shifting to power saving Burst Mode operation at light loads. High efficiency is maintained over a broad 100uA to 100mA load range. The LT1307B does not shift into Burst Mode operation at light loads, eliminating low frequency output ripple at the expense of light load efficiency. The devices contain a low-battery detector with a 200mV reference and shut down to less than 5µA. No load quiescent current of the LT1307 is 50µA and the internal NPN power switch handles a 500mA current with a voltage drop of just 295mV.Unlike competitive devices, large electrolytic capacitors are not required with the LT1307/LT1307B in single cell applications. The high frequency (600kHz) switching allows the use of tiny surface mount multilayer ceramic (MLC) capacitors along with small surface mount inductors. The devices work with just 10µF of output capacitance and require only 1µF of input bypassing.The LT1307/LT1307B are available in 8-lead MSOP, PDIP and SO packages.ApplicationsPagersCordless TelephonesGPS ReceiversBattery BackupPortable Electronic EquipmentGlucose MetersDiagnostic Medical Instrumentation

The LT1308A/LT1308B are micropower, fixed frequency step-up DC/DC converters that operate over a 1V to 10V input voltage range. They are improved versions of the LT1308 and are recommended for use in new designs. The LT1308A features automatic shifting to power saving Burst Mode operation at light loads and consumes just 140µA at no load. The LT1308B features continuous switching at light loads and operates at a quiescent current of 2.5mA. Both devices consume less than 1µA in shutdown.Low-battery detector accuracy is significantly tighter than the LT1308. The 200mV reference is specified at ±2% at room and ±3% over temperature. The shutdown pin enables the device when it is tied to a 1V or higher source and does need to be tied to VINas on the LT1308. An internal VCCclamp results in improved transient response and the switch voltage rating has been increased to 36V, enabling higher output voltage applications.The LT1308A/LT1308B are available in the 8-lead SO and the 14-lead TSSOP packages.FeaturesLT1308Not Recommended For New DesignsLT1308AImproved Transient Response, Burst ModeLT1308BImproved Transient Response, Burst Mode DisabledApplicationsGSM/CDMA PhonesDigital CamerasLCD Bias SuppliesAnswer-Back PagersGPS ReceiversBattery Backup SuppliesHandheld Computers