LINEAR Manuals

The LTC1483 is an ultra-low power differential line transceiver designed for data transmission standard RS485 applications with extended common-mode range (–7V to 12V). It will also meet the requirements of RS422. The LTC1483 features output drivers with controlled slew rate, decreasing the EMI radiated from the RS485 lines, and improving signal fidelity with misterminated lines. The CMOS design offers significant power savings over its bipolar counterparts without sacrificing ruggedness against overload or ESD damage. Typical quiescent current is only 80µA while operating and less than 1µA in shutdown. The driver and receiver feature three-state outputs, with the driver outputs maintaining high impedance over the entire common-mode range. Excessive power dissipation caused by bus contention or faults is prevented by a thermal shutdown circuit which forces the driver outputs into a high impedance state. The receiver has a fail-safe feature which guarantees a high output state when the inputs are left open. I/O pins are protected against multiple ESD strikes of over ±10kV. The LTC1483 is fully specified over the commercial and extended industrial temperature range and is available in 8-pin DIP and SO packages.

LTC4006 is a 4A high efficiency Li-ion battery charger

The LTC ®1759 Smart Battery Charger is a single chip charging solution that dramatically simplifies construc- tion of an SBS compliant system. The LTC1759 imple- ments a Level 2 charger function whereby the charger can be programmed by the battery or by the host. A thermistor on the battery being charged is monitored for tempera- ture, connectivity and battery type information. The SMBus interface remains alive when the AC power adapter is removed and responds to all SMBus activity directed to it, including thermistor status (via the ChargerStatus com- mand). The charger also provides an interrupt to the host whenever a status change is detected (e.g., battery removal, AC adapter connection). Charging current and voltage are restricted to chemistry specific limits for improved system safety and reliability. Limits are programmable by two external resistors. Addi- tionally, the maximum average current from the AC adapter is programmable to avoid overloading the adapter when simultaneously supplying load current and charging cur- rent. When supplying system load current, charging cur- rent is automatically reduced to prevent adapter overload.

The LTC3720 is a synchronous step-down switching regulator controller for CPU power. It supports programmable output voltage between 1.05V and 1.825V, does not require a sense resistor, and has features such as wide input voltage range, adjustable current limit, and switching frequency.

The LTC3559/LTC3559-1 are USB battery chargers with dual high efficiency buck regulators. The parts are ideally suited to power single-cell Li-Ion/Polymer based handheld applications needing multiple supply rails. Battery charge current is programmed via the PROG pin and the HPWR pin, with capability up to 950mA at the BAT pin. The battery charger has an NTC input for temperature qualified charging. The CHRG pin allows battery status to be monitored continuously during the charging process. An internal timer controls charger termination. Each monolithic synchronous buck regulator provides up to 400mA of output current while operating at efficiencies greater than 90% over the entire Li-Ion/Polymer range. A MODE pin provides the flexibility to place both buck regulators in a power saving Burst Mode operation or a low noise pulse skip mode. The LTC3559/LTC3559-1 are offered in a low profile thermally enhanced 16-lead (3mm × 3mm) QFN package.

The LT1533 is a new class of switching regulator designed to reduce conducted and radiated electromagnetic interference (EMI). It features ultralow noise and EMI, high efficiency, and independent control of switch voltage and current slew rates.

The LTC1702 is a dual switching regulator controller opti- mized for high efficiency with low input voltages.

The LTC3401 is a high-efficiency, fixed-frequency, step-up DC/DC converter that operates from an input voltage below 1V. The device includes a 0.16Ω N-channel MOSFET switch and a 0.18Ω P-channel synchronous rectifier. Switching frequencies up to 3MHz are programmed with an external timing resistor and the oscillator can be synchronized to an external clock. An external Schottky diode is optional but will slightly improve efficiency. 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 fixed frequency switching is enabled. Other features include 1µA shutdown, antiringing control, open-drain power good output, thermal shutdown and current limit. The LTC3401 is available in the 10-lead thermally enhanced MSOP package. Higher current applications should use the 2A rated LTC3402 synchronous boost converter. Applications that require VOUT < 2.6V should use the LTC3423. All-Ceramic-Capacitor 2-Cell to 3.3V at 500mA Step-Up Converter.

The LT1767 is a 1.25MHz monolithic buck switching regulator with features such as high efficiency, wide operating voltage range, and low power consumption. It uses current mode control to provide fast transient response and excellent loop stability.

The LTC1703 is a dual switching regulator controller optimized for high efficiency with low input voltages. It includes two complete, on-chip, independent switching regulator controllers. Each is designed to drive a pair of external N-channel MOSFET devices in a voltage mode feedback, synchronous buck configuration. It uses a constant- frequency, true PWM design switching at 550kHz, minimiz- ing external component size and cost and optimizing load transient performance.

The LT ®3431 is a 500kHz monolithic buck switching regu- lator that accepts input voltages up to 60V. A high efficiency 3A, 0.1Ω switch is included on the die along with all the nec- essary oscillator, control and logic circuitry.

The LT1610 is a micropower fixed frequency DC/DC converter that operates from an input voltage as low as 1V. Intended for small, low power applications, it switches at 1.7MHz, allowing the use of tiny capacitors and inductors. The device can generate 3V at 30mA from a single cell (1V) supply. An internal compensation network can be connected to the LT1610’s VC pin, eliminating two external components. No-load quiescent current of the LT1610 is 30µA, and the internal NPN power switch handles a 300mA current with a voltage drop of 300mV. The LT1610 is available in 8-lead MSOP and SO packages.

The LTC4257 is a complete power interface power supply chip designed for IEEE 802.3af PoE systems. It integrates 25k signature resistors, classification current sources, input current limiting with thermal foldback, undervoltage lockout, and power good signaling, all in a single 8-pin package. The chip integrates a high-voltage power MOSFET, which reduces the cost for system designers and saves board space. LTC4257 can directly interface with Linear Technology's various DC/DC converter products to provide an economical power solution for IP phones, wireless access points and other PDs. Linear Technology also provides solutions for PSE applications based on quad network power controllers. LTC4257 is available in 8-pin SO and low profile (3mm x 3mm) DFN packages.

LTC3738 3738f is a 3-phase step-down switch- ing regulator controller from Linear Technology Corporation. It is mainly used in high-performance notebook computers, servers, desktop computers and workstations. The controller supports 3-phase synchronous step-down switching power supply, and can drive all N-channel external power MOSFET stages. The working frequency is 210kHz to 530kHz.

The LTC ®3707 is a high performance dual step-down switching regulator controller that drives N-channel syn- chronous power MOSFET stages.