Analog Devices

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

The LT1316 is a micropower step-up DC/DC converter that operates from an input voltage as low as 1.5V. A programmable input current limiting function allows precise control of peak switch current. Peak switch current can be set to any value between 30mA and 500mA by adjusting one resistor. This is particularly useful for DC/DC converters operating from high source impedance inputs such as lithium coin cells or telephone lines.The fixed off-time, variable on-time regulation scheme results in quiescent current of only 33µA in active mode. Quiescent current decreases to 3µA in shutdown with the low-battery detector still active.The LT1316 is available in 8-lead MSOP and SO packages.ApplicationsBattery BackupLCD BiasLow Power –48V to 5V/3.3V Converters

The LT1317/LT1317B are micropower, fixed frequency step-up DC/DC converters that operate over a wide input voltage range of 1.5V to 12V. The LT1317 features automatic shifting to power saving Burst Mode™operation at light loads. High efficiency is maintained over a broad 300µA to 200mA load range. Peak switch current during Burst Mode operation is kept below 250mA for most operating conditions which results in low output ripple voltage, even at high input voltages. The LT1317B does not shift into Burst Mode operation at light loads, eliminating low frequency output ripple at the expense of light load efficiency.The LT1317/LT1317B contain an internal low-battery detector with a 200mV reference that stays alive when the device goes into shutdown.No-load quiescent current of the LT1317 is 100µA and shuts down to 30µA. The internal NPN power switch handles a 500mA current with a voltage drop of just 300mV.The LT1317/LT1317B are available in MS8 and SO-8 packages.ApplicationsCellular TelephonesCordless TelephonesPagersGPS ReceiversBattery BackupPortable Electronic EquipmentGlucose MetersDiagnostic Medical Instrumentation

The LT1328 is a photodiode receiver that supports IrDA®data rates up to 4Mbps as well as other modulation methods such as Sharp ASK and TV remote control. The LT1328 MSOP contains all the necessary circuitry to convert current pulses from an external photodiode to a digital TTL output while rejecting unwanted lower frequency interference. The LT1328 plus five external components is all that is required to make an IrDA compatible receiver.Power requirements for the LT1328 are minimal—a single 5V supply and 2mA of quiescent current. Internal high-pass filtering attenuates interfering signals such as sunlight, incandescent and fluorescent lamps and is selectable at Pin 7 for low or high data rates. The LT1328’s ease of use and flexibility make it an ideal solution for numerous other photodiode receiver applications. The LT1328 is available in the SO-8 as well as the tiny MSOP for size-critical applications.ApplicationsIrDA ApplicationsSharp/NewtonTV RemoteNoncontact TelemetryWireless Slave for Photographic FlashKeyless EntryOptical Data TransferInfrared Home Control Systems

The LT1330 is a three driver, five receiver RS232 transceiver with low supply current. Designed to interface with new 3V logic, the LT1330 operates with both a 5V power supply and a 3V logic power supply. The chip may be shut down to micropower operation with one receiver remaining active to monitor RS232 inputs such as ring detect from a modem.The LT1330 is fully compliant with all EIA RS232 specifications. Additionally, the RS232 line input and output pins are resilient to multiple ±10kV ESD strikes. This eliminates the need for costly TransZorbs®on line pins for the RS232 part.The LT1330 operates to 120kbaud even driving high capacitive loads. During shutdown, driver and receiver outputs are at a high impedance state allowing devices to be paralleled.ApplicationsNotebook ComputersPalmtop Computers

The LT1331 is a 3-driver, 5-receiver RS232 transceiver designed for 3V and mixed 3V/5V systems. Receivers operate from 3V logic supply VL, while the onboard charge pump and drivers operate from 5V or 3V supply VCC.The transceiver has two shutdown modes. One mode disables the drivers and the charge pump, the other shuts down all circuitry except for one low power receiver which can be used for ring detection. The VCCsupply may be shut down while in ring detection mode. While shut down, the drivers and receivers assume high impedance output states.The LT1331 is fully compliant with all EIA-RS232 specifications when VCC= 5V. If VCC= 3V, output drive levels are compatible with all known interface circuits. Special bipolar construction techniques protect the drivers and receivers beyond the fault conditions stipulated for RS232. The RS232 I/O pins are resilient to multiple ±10kV ESD strikes. An advanced driver output stage operates up to 120kbaud while driving heavy capacitive loads.ApplicationsNotebook ComputersPalmtop Computers