Analog Devices

The LTC1286/LTC1298 are micropower, 12-bit, successive approximation sampling A/D converters. They typically draw only 250µA of supply current when converting and automatically power down to a typical supply current of 1nA whenever they are not performing conversions. They are packaged in 8-pin SO packages and operate on 5V to 9V supplies. These 12-bit, switched-capacitor, successive approximation ADCs include sample-and-holds. The LTC1286 has a single differential analog input. The LTC1298 offers a software selectable 2-channel MUX.On-chip serial ports allow efficient data transfer to a wide range of microprocessors and microcontrollers over three wires. This, coupled with micropower consumption, makes remote location possible and facilitates transmitting data through isolation barriers.These circuits can be used in ratiometric applications or with an external reference. The high impedance analog inputs and the ability to operate with reduced spans (to 1.5V full scale) allow direct connection to sensors and transducers in many applications, eliminating the need for gain stages.ApplicationsBattery-Operated SystemsRemote Data AcquisitionBattery MonitoringHandheld Terminal InterfaceTemperature MeasurementIsolated Data Acquisition

The LTC1321/LTC1322/LTC1335 are low power CMOS bidirectional transceivers, each featuring two reconfigurable interface ports. Each can be configured as two RS485 differential ports, as two single-ended ports, or as one RS485 differential port and one single-ended port. The LTC1321/LTC1322 can provide RS232 or EIA562 compatible single-ended outputs; the LTC1335 provides EIA562 compatible outputs and additionally includes an output enable pin, allowing the receiver logic level outputs to be three-stated.The RS232/EIA562 transceivers operate to 120kbaud and are in full compliance with EIA/TIA-562 specification. The RS485 transceivers operate to 10Mbaud and are in full compliance with RS485 and RS422 specifications. All interface drivers feature short-circuit and thermal shutdown protection. An enable pin allows RS485 driver outputs to be forced into high impedance which is maintained even when the outputs are forced beyond supply rails or power is off. Both driver outputs and receiver inputs feature ±10kV ESD protection. A loopback mode connects the driver outputs back to the receiver inputs for diagnostic self-test.The LTC1321/LTC1322 can support RS232 voltage levels when 6.5V ≤ VDD≤ 10V and –6.5V ≥ VEE≥ –10V. The LTC1335 supports receiver output enable but not RS232 levels. A shutdown mode reduces the ICCsupply current to 15µA.ApplicationsLow Power RS485/RS422/EIA562/RS232 InterfaceCable RepeaterLevel Translator

The LTC1323 is a multi-protocol line transceiver designed to operate on AppleTalk or EIA562-compatible single-ended networks while operating from a single 5V supply. There are two versions of the LTC1323 available: a 16-pin version designed to connect to an AppleTalk network, and a 24-pin version which also includes the additional single-ended drivers and receivers necessary to create an Apple-compatible serial port. An on-board charge pump generates a ­5V supply which can be used to power external devices. Additionally, the 24-pin LTC1323 features a micropower keep-alive mode during which one of the single-ended receivers is kept active to monitor external wake-up signals. The LTC1323 draws only 2.4mA quiescent current when active, 65µA in receiver keep-alive mode, and 0.5µA in shutdown, making it ideal for use in battery-powered systems.The differential driver can drive either differential AppleTalk loads or conventional single-ended loads. The driver outputs three-state when disabled, during shutdown, in receiver keep-alive mode, or when the power is off. The driver outputs will maintain high impedance even with output common-mode voltages beyond the power supply rails. Both the driver outputs and receiver inputs are protected against ESD damage to ±10kV.ApplicationsLocalTalk PeripheralsNotebook/Palmtop ComputersBattery-Powered Systems

The LTC1325 provides the core of a flexible, cost-effective solution for an integrated battery management system. The monolithic CMOS chip controls the fast charging of nickel-cadmium, nickel-metal-hydride, lead-acid or lithium batteries under microprocessor control. The device features a programmable 111kHz PWM constant current source controller with built-in FET driver, 10-bit ADC, internal voltage regulator, discharge-before-charge controller, programmable battery voltage attenuator and an easy-to-use serial interface.The chip may operate in one of five modes: power shut-down, idle, discharge, charge or gas gauge. In power shutdown the supply current drops to 30µA and in the idle mode,an ADC reading maybe made without any switching noise affecting the accuracy of the measurement. In the discharge mode, the battery is discharged by an external transistor while the battery is being monitored by the LTC1325 for fault conditions. The charge mode is terminated by the µP while monitoring any combination of battery voltage and temperature, ambient temperature and charge time. The LTC1325 also monitors the battery for fault conditions before and during charging. In the gas gauge mode the LTC1325 allows the total charge leaving the battery to be calculated.ApplicationsSystem Integrated Battery Charger

The LTC1326/LTC1326-2.5 are triple supply monitors intended for systems with multiple supply voltages. They provide micropower operation, small size and high accuracy supply monitoring.Tight 0.75% threshold accuracy and glitch immunity ensure reliable reset operation without false triggering. The 20µA typical supply current makes the LTC1326/LTC1326-2.5 ideal for power-conscious systems.TheRSToutput is guaranteed to be in the correct state for VCC3, VCC5or VCC25down to 1V. The LTC1326/LTC1326-2.5 can be configured to monitor one, two or three inputs, depending on system requirements.A manual push-button reset input provides the ability to generate a very narrow "soft" reset pulse (100µs typ) or a 200ms reset pulse equivalent to a power-on reset. BothSRSTandRSToutputs are open-drain and can be OR-tied with other reset sources.ApplicationsDesktop ComputersNotebook ComputersIntelligent InstrumentsPortable Battery-Powered Equipment

The LTC1327 is an advanced low power, three-driver/five-receiver EIA/TIA-562 transceiver. In the no load condition, the supply current is only 300µA. The charge pump only requires four 0.1µF capacitors.In SHUTDOWN mode, the supply current is further reduced to 0.2µA. All EIA/TIA-562 outputs assume a high impedance state in SHUTDOWN and with the power off.The LTC1327 is fully compliant with all data rate and overvoltage EIA/TIA-562 specifications. The transceiver can operate up to 120k Baud with a 1000pF//3kΩ load. Both driver outputs and receiver inputs can be forced to ±25V without damage, and can survive multiple ±10kV ESD strikes.ApplicationsNotebook ComputersPalmtop Computers

The LTC1329-10/LTC1329-50 are micropower 8-bit current output D/A converters (DACs) with an output range of 0µA to 10µA and 0µA to 50µA for the -10 and -50 versions respectively. In 3.3V or 5V systems, the DAC current output can be biased from –17V to 2V or –17V to 2.5V respectively. The supply current is only 0.2µA in Shutdown.The LTC1329 can communicate with external circuitry by using one of three interface modes: standard SPI mode and two pulse modes. Upon power-up, the internal counter resets to 80H, the DAC output assumes mid-range and the chip is configured to SPI or pulse mode depending on the signal level atCS.In SPI mode, the system MPU can serially transfer 8-bit data to and from the LTC1329. In pulse mode, the upper six bits of the DAC output can be programmed for increment-only (1-wire interface) or increment/decrement (2-wire interface) operation depending on the signal level at DIN. In increment-only operation, when counter increases beyond full scale, the counter rolls over and sets the DAC to zero. In this way, a single pulse applied to CLK increases the upper six bits of the counter by one step and 63 pulses decrease them by one step. In increment/decrement, the counter stops incrementing at full scale and decrementing at zero and will not roll over.LTC1329 is available in 8-pin PDIP and SO packages.ApplicationsLCD Contrast ControlBacklight Brightness ControlPower Supply Voltage AdjustmentBattery Charger Current/Voltage AdjustmentGaAs FET Bias AdjustmentTrimmer Pot EliminationLow Power and Battery-Operated SystemsHandheld or Portable Instruments

The LTC1334 is a low power CMOS bidirectional transceiver featuring two reconfigurable interface ports. It can be configured as two RS485 differential ports, as two dual RS232 single-ended ports or as one RS485 differential port and one dual RS232 single-ended port. An onboard charge pump requires four 0.1µF capacitors to generate boosted positive and negative supplies, allowing the RS232 drivers to meet the RS232 ±5V output swing requirement with only a single 5V supply. A shutdown mode reduces the ICCsupply current to 10µA.The RS232 transceivers are in full compliance with RS232 specifications. The RS485 transceivers are in full compliance with RS485 and RS422 specifications. All interface drivers feature short-circuit and thermal shutdown protection. An enable pin allows RS485 driver outputs to be forced into high impedance, which is maintained even when the outputs are forced beyond supply rails or power is off. Both driver outputs and receiver inputs feature ±10kV ESD protection. A loopback mode allows the driver outputs to be connected back to the receiver inputs for diagnostic self-test.ApplicationsLow Power RS485/RS422/RS232/EIA562 InterfaceSoftware-Selectable Multiprotocol Interface PortCable RepeatersLevel Translators