LINEAR Manuals

This document introduces LT1680, a high-power, current-mode switching power supply controller optimized for boost topologies. The IC drives an N-channel MOSFET switch for DC/DC converter applications up to 60V input. A high current gate drive output handles up to 10,000pF gate capacitance, enabling the construction of high power DC/DC convert- ers. Current sense common mode range up to 60V allows current sensing to be referenced to the input supply, eliminating the need for sense blanking circuits. The LT1680 incorporates programmable average current limiting allowing accurate limiting of DC current in the magnetics, independent of ripple current . User adjustable slope compensation provides stable operation at duty cycles up to 90%. The LT1680 operating frequency is programmable and can be synchronized up to 200kHz. Minimum off-time operation provides switch protection. The IC also incorpo- rates a soft start feature that is gated by both shutdown and undervoltage lockout conditions.

The LT3011 is a high voltage, micropower, low dropout linear regulator. The device is capable of supplying 50mA of output current with a dropout voltage of 300mV. Designed for use in battery-powered high voltage systems, the low quiescent current (46μA operating and 1μA in shutdown) is well controlled in dropout, making the LT3011 an ideal choice. The LT3011 includes a PWRGD flag to indicate output regulation. The delay between regulated output level and flag indication is programmable with a single capacitor. The LT3011 also has the ability to operate with very small output capacitors; it is stable with only 1μF on the output. Small ceramic capacitors can be used without the addition of any series resistance (ESR) as is common with other products.

The LTM4600HV is a high-efficiency 10A DC/DC µModule suitable for applications with an input voltage range of 4.5V to 28V and an output voltage range of 0.6V to 5V. This product adopts a high switching frequency and an adaptive on-time current mode architecture, enabling a very fast transient response to line and load changes. Fault protection features include integrated overvoltage and short circuit protection with a defeatable shutdown timer. The product also features a built-in soft-start timer that can be adjusted with a small capacitor. The LTM4600HV is packaged in a low-profile package, allowing for high-density point-to-point regulation using unused space on the bottom of the PCB.

The LTC1564 is a new type of continuous time filter for antialiasing, reconstruction and other band-limiting applications. It has one analog input pin and one analog output pin. The cutoff frequency (fC) and gain are programmable while the shape of the lowpass response is fixed. A latching digital interface stores fC and gain settings or it can be bypassed for control directly from the pins. The LTC1564 operates from 2.7V to 10V total (single or split supplies) and comes in a 16-pin surface mount package.

LTC3448 3448f is a high efficiency synchronous step-down regulator with optional linear regulator mode. It has 1.5MHz or 2.25MHz switching frequency and 600mA output current. It supports low output voltage.

The LTC1698 is a precision secondary-side forward converter controller that synchronously drives external N-channel MOSFETs. It is designed for use with the LT3781 primary-side synchronous forward converter controller to create a completely isolated power supply. The LT3781 synchronizes the LTC1698 through a small pulse transformer and the LTC1698 drives a feedback optocoupler to close the feedback loop. Output accuracy of ±0.8% and high efficiency over a wide range of load currents are obtained. The LTC1698 provides accurate secondary-side current limit using an external current sense resistor. The input voltage at the MARGIN pin provides ±5% output voltage adjustment. A power good flag and overvoltage input are provided to ensure proper power supply conditions. An auxiliary 3.3V logic supply is included that supplies up to 10mA of output current.

The LT1461 is a family of low dropout micropower bandgap references that combine very high accuracy and low drift with low supply current and high output drive. These series references use advanced curvature compensation techniques to obtain low temperature coefficient and trimmed precision thin-film resistors to achieve high output accuracy. The LT1461 family draws only 35µA of supply current, making them ideal for low power and portable applications, however their high 50mA output drive makes them suitable for higher power requirements, such as precision regulators. In low power applications, a dropout voltage of less than 300mV ensures maximum battery life while maintaining full reference performance. Line regulation is nearly immeasur- able, while the exceedingly good load and thermal regulation will not add significantly to system error budgets. The shutdown feature can be used to switch full load currents and can be used for system power down. Thermal shutdown protects the part from overload conditions.

1 LT1424-9 SN14249 14249FS 9V output isolated flyback switching regulator, no transformer "third winding" or opto-isolator required, application circuit meets PCMCIA Type II height requirement, fixed, application specific 9V output voltage, regulation maintained well into discontinuous mode (light load), load compensation provides excellent load regulation, available in 8-pin PDIP and SO packages, operating frequency: 285kHz. The LT ®1424-9 is a monolithic high power switching regulator specifically designed for the isolated flyback topology. No "third winding" or opto-isolator is required; the integrated circuit senses the isolated output voltage directly from the primary side flyback waveform. A high current, high efficiency switch is included on the die along with all oscillator, control and protection circuitry. The LT1424-9 operates with input supply voltages from 3V to 20V and draws only 7mA quiescent current. It can deliver up to 200mA at 9V with no external power devices. By utilizing current mode switching techniques, it pro- vides excellent AC and DC line regulation. The LT1424-9 has a number of features not found on other switching regulator ICs. Its unique control circuitry can maintain regulation well into discontinuous mode. Load compensation circuitry allows for improved load regula- tion. An externally activated shutdown mode reduces total supply current to 20µA typical for standby operation. -9V PCMCIA Type II Isolated LAN Supply (2.41mm Maximum Height).

The LTC ®1096/LTC1096L/LTC1098/LTC1098L are micropower, 8-bit A/D converters that draw only 80µA of supply current when converting.

The LTC ®3423 and LTC3424 are high efficiency, fixed frequency, step-up DC/DC converters that can regulate output voltages as low as 1.5V from a single cell. An applied voltage of at least 2.7V to the VDD pin is required to power the internal control circuitry. The devices include a 0.16Ω N-channel MOSFET switch and a 0.21Ω P-channel synchronous rectifier. The LTC3423 is intended for applications requiring less than 0.75W of output power and the LTC3424 for 1.5W or less. Switching frequencies up to 3MHz are programmed with an external timing resistor and the oscillator can be synchronized to an external clock. Quiescent current is only 38µA in Burst Mode operation, maximizing battery life in portable applications. Burst Mode operation is user controlled and can be enabled by driving the MODE/SYNC pin high. If the MODE/SYNC pin has either a clock or is driven low then the operation is at constant fixed frequency. Other features include a 1µA shutdown, thermal shutdown and current limit. The LTC3423 and LTC3424 are available in the 10-lead MSOP package. For applications requiring an output voltage greater than 2.6V, the LTC3401 and LTC3402 are recommended without the need of a separate voltage for the VDD pin.

This datasheet introduces the LTC ®1197/LTC1197L/LTC1199/LTC1199L 10-bit A/D converters, including working principle, package, supply voltage, sampling rate, power consumption and other information.

LTC1286/LTC1298 Micropower Sampling 12-Bit A/D Converters In S0-8 Packages

The LTC1698 is a precision secondary-side forward converter controller that synchronously drives external N-channel MOSFETs. It is designed for use with the LT3781 primary-side synchronous forward converter controller to create a completely isolated power supply. The LT3781 synchronizes the LTC1698 through a small pulse transformer and the LTC1698 drives a feedback optocoupler to close the feedback loop. Output accuracy of ±0.8% and high efficiency over a wide range of load currents are obtained. The LTC1698 provides accurate secondary-side current limit using an external current sense resistor. The input voltage at the MARGIN pin provides ±5% output voltage adjustment. A power good flag and overvoltage input are provided to ensure proper power supply conditions. An auxiliary 3.3V logic supply is included that supplies up to 10mA of output current.

The LTC3716 is a 2-phase, VID programmable, synchronous step-down switching regulator controller that drives two N-channel external power MOSFET stages in a fixed frequency architecture. The 2-phase controller drives its two output stages out of phase at frequencies up to 300kHz to minimize the RMS ripple currents in both input and output capacitors. The 2-phase technique effectively multiplies the fundamental frequency by two, improving transient response while operating each channel at an optimum frequency for efficiency. Thermal design is also simplified. An operating mode select pin (FCB) can be used to regulate a secondary winding or select among three modes including Burst Mode TM operation for highest efficiency. An internal differential amplifier provides true remote sensing of the regulated supply’s positive and negative output terminals as required in high current applications. The RUN/SS pin provides soft-start and optional timed, short-circuit shutdown. Current foldback limits MOSFET dissipation during short-circuit conditions when the overcurrent latchoff is disabled. OPTI-LOOP compensation allows the transient response to be optimized for a wide range of output capacitors and ESR values.

The LTC1594L/LTC1598L are 3V micropower, 12-bit sampling A/D converters that feature 4- and 8-channel multiplexers, respectively. They typically draw only 160µA of supply current when converting and automatically power down to a typical supply current of 1nA between conversions. The LTC1594L is available in a 16-pin SO package and the LTC1598L is packaged in a 24-pin SSOP. Both operate on a 3V supply. The 12-bit, switched-capacitor, successive approximation ADCs include a sample-and-hold. On-chip serial ports allow efficient data transfer to a wide range of microprocessors and microcontrollers over three or four wires. This, coupled with micropower consumption, makes remote location possible and facilitates transmitting data through isolation barriers. The circuit 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.