Analog Devices

The LT1959 is a 500kHz monolithic buck mode switching regulator functionally identical to the LT1506 but optimized for lower output voltage applications. It will operate down to 1.21V output compared to 2.42V for the LT1506. A 4.5A switch is included on the die along with all the necessary oscillator, control and logic circuitry. High switching frequency allows a considerable reduction in the size of external components. The topology is current mode for fast transient response and good loop stability.A special high speed bipolar process and new design techniques achieve high efficiency at high switching frequency. Efficiency is maintained over a wide output current range by keeping quiescent supply current to 4mA and by utilizing a supply boost capacitor to saturate the power switch.The LT1959 fits into standard 7-pin DD and fused lead SO-8 packages. Full cycle-by-cycle short-circuit protection and thermal shutdown are provided. Standard surface mount external parts are used, including the inductor and capacitors. There is the optional function of shutdown or synchronization. A shutdown signal reduces supply current to 20µA. Synchronization allows an external logic level signal to increase the internal oscillator from 580kHz to 1MHz.ApplicationsPortable ComputersBattery-Powered SystemsBattery ChargersDistributed Power5V to 3.3V Conversion5V to 2.5V Conversion5V to 1.8V Conversion

The LT1961 is a 1.25MHz monolithic boost switching regulator. A high efficiency 1.5A, 0.2Ω switch is included on the die together with all the control circuitry required to complete a high frequency, current-mode switching regulator. Current-mode control provides fast transient response and excellent loop stability.New design techniques achieve high efficiency at high switching frequencies over a wide operating voltage range. A low dropout internal regulator maintains consistent performance over a wide range of inputs from 24V systems to Li-Ion batteries. An operating supply current of 1mA maintains high efficiency, especially at lower output currents. Shutdown reduces quiescent current to 6µA. Maximum switch current remains constant at all duty cycles. Synchronization allows an external logic level signal to increase the internal oscillator from 1.5MHz to 2MHz.The LT1961 is available in an exposed pad, 8-pin MSOP package. Full cycle-by-cycle switch current limit protection and thermal shutdown are provided. High frequency operation allows the reduction of input and output filtering components and permits the use of chip inductors.ApplicationsDSL ModemsPortable ComputersBattery-Powered SystemsDistributed Power

The LT1963 series are low dropout regulators optimized for fast transient response. The devices are capable of supplying 1.5A of output current with a dropout voltage of 340mV. Operating quiescent current is 1mA, dropping to <1μA in shutdown. Quiescent current is well controlled; it does not rise in dropout as it does with many other regulators. In addition to fast transient response, the LT1963 regulators have very low output noise which makes them ideal for sensitive RF supply applications.Output voltage range is from 1.21V to 20V. The LT1963 regulators are stable with output capacitors as low as 10µF. Internal protection circuitry includes reverse battery protection, current limiting, thermal limiting and reverse current protection. The devices are available in fixed output voltages of 1.5V, 1.8V, 2.5V, 3.3V and as an adjustable device with a 1.21V reference voltage. The LT1963 regulators are available in 5-lead TO-220, DD, 3-lead SOT-223, 8-lead SO, and Exposed Pad 16-lead TSSOP packages.FeaturesLT1963-LT1963AStable With Ceramic Output CapacitorsApplications3.3V to 2.5V Logic Power SuppliesPost Regulator for Switching Supplies

The LT1964 is a micropower low noise, low dropout negative regulator. The device is capable of supplying 200mA of output current with a dropout voltage of 340mV. Low quiescent current (30µA operating and 3µA shutdown) makes the LT1964 an excellent choice for battery-powered applications. Quiescent current is well controlled in dropout.Other features of the LT1964 include low output noise. With the addition of an external 0.01µF bypass capacitor, output noise is reduced to 30µVRMSover a 10Hz to 100kHz bandwidth. The LT1964 is capable of operating with small capacitors and is stable with output capacitors as low as 1µF. Small ceramic capacitors can be used without the necessary addition of ESR as is common with other regulators. Internal protection circuitry includes reverse output protection, current limiting, and thermal limiting. The device is available with a fixed output voltage of –5V and as an adjustable device with a –1.22V reference voltage. The LT1964 regulators are available in a low profile (1mm) ThinSOT and the low profile (0.75mm) 8-pin (3mm × 3mm) DFN packages.ApplicationsBattery-Powered InstrumentsLow Noise Regulator for Noise-Sensitive InstrumentationNegative Complement to LT1761 Family of Positive LDOs

The LT1965 series are low noise, low dropout linear regulators. The devices supply 1.1A of output current with a 310mV typical dropout voltage. Operating quiescent current is 500μA for the adjustable version, reducing to <1μA in shutdown. Quiescent current is well controlled; it does not rise in dropout as with many other regulators. The LT1965 regulators have very low output noise which makes them ideal for sensitive RF and DSP supply applications.Output voltage ranges from 1.20V to 19.5V. The LT1965 regulators are stable with output capacitors as low as 10μF. Internal protection circuitry includes reverse-battery protection, current limiting with foldback, thermal limiting and reverse-current protection. The LT1965 series are available in fixed output voltages of 1.5V, 1.8V, 2.5V, 3.3V, and as an adjustable device with a 1.20V reference voltage. The package offerings include the 5-lead TO-220, 5-lead DD-Pak as well as the thermally enhanced 8-lead MSOP and low profile (0.75mm) 8-lead 3mm × 3mm DFN.ApplicationsLogic Power SuppliesPost Regulator for Switching SuppliesLow Noise Instrumentation

The LT1970 is a ±500mA power op amp with precise externally controlled current limiting. Separate control voltages program the sourcing and sinking current limit sense thresholds with 2% accuracy. Output current may be boosted by adding external power transistors.The circuit operates with single or split power supplies from 5V to 36V total supply voltage. In normal operation, the input stage supplies and the output stage supplies are connected (VCCto V+and VEEto V–). To reduce power dissipation it is possible to power the output stage (V+, V–) from independent, lower voltage rails. The amplifier is unity-gain stable with a 3.6MHz gain bandwidth product and slews at 1.6V/µs. The current limit circuits operate with a 2MHz response between the VCSRCor VCSNKcontrol inputs and the amplifier output.Open collector status flags signal current limit circuit activation, as well as thermal shutdown of the amplifier. An enable logic input puts the amplifier into a low power, high impedance output state when pulled low. Thermal shutdown and a ±800mA fixed current limit protect the chip under fault conditions.The LT1970 is packaged in a 20-lead TSSOP package with a thermally conductive copper bottom plate to facilitate heat sinking.ApplicationsAutomatic Test EquipmentLaboratory Power SuppliesMotor DriversThermoelectric Cooler Driver

The LT1976/LT1976B are 200kHz monolithic step-down switching regulators that accept input voltages up to 60V. A high efficiency 1.5A, 0.2Ω switch is included on the die along with all the necessary oscillator, control and logic circuitry. Current mode topology is used for fast transient response and good loop stability.Innovative design techniques along with a new high voltage process achieve high efficiency over a wide input range. Efficiency is maintained over a wide output current range by employing Burst Mode operation at low currents, utilizing the output to bias the internal circuitry, and by using a supply boost capacitor to fully saturate the power switch. The LT1976B does not shift into Burst Mode operation at low currents, eliminating low frequency output ripple at the expense of efficiency. Patented circuitry maintains peak switch current over the full duty cycle range.* Shutdown reduces input supply current to less than 1µA. External synchronization can be implemented by driving the SYNC pin with logic-level inputs. A single capacitor from the CSSpin to the output provides a controlled output voltage ramp (soft-start). The devices also have a power good flag with a programmable threshold and time-out and thermal shutdown protection.The LT1976/LT1976B are available in a 16-pin TSSOP package with Exposed Pad leadframe for low thermal resistance.ApplicationsHigh Voltage Power Conversion14V and 42V Automotive SystemsIndustrial Power SystemsDistributed Power SystemsBattery-Powered Systems

The LT1977 is a 500kHz monolithic buck switching regulator that accepts input voltages up to 60V. A high efficiency 1.5A, 0.2Ω switch is included on the die along with all the necessary oscillator, control and logic circuitry. Current mode topology is used for fast transient response and good loop stability.Innovative design techniques along with a new high voltage process achieve high efficiency over a wide input range. Efficiency is maintained over a wide output current range by employing Burst Mode operation at low currents, utilizing the output to bias the internal circuitry, and by using a supply boost capacitor to fully saturate the power switch. Patented circuitry maintains peak switch current over the full duty cycle range. Shutdown reduces input supply current to less than 1µA. External synchronization can be implemented by driving the SYNC pin with logic-level inputs. A single capacitor from the CSSpin to the output provides a controlled output voltage ramp (soft-start). The device also has a power good flag with a programmable threshold and time-out and thermal shutdown protection.The LT1977 is available in a 16-pin TSSOP package with exposed pad leadframe for low thermal resistance. The LT1976, a 200kHz reduced switch frequency version of the LT1977, is also available. See the Applications Information section for selection criteria between the LT1976 and LT1977.ApplicationsHigh Voltage Power Conversion14V and 42V Automotive SystemsIndustrial Power SystemsDistributed Power SystemsBattery-Powered Systems

The LT®1990-10 is a micropower precision difference amplifier with a very high common mode input voltage range, a fixed gain of 10 and 100kHz bandwidth. The LT1990-0 operates over a ±250V common mode voltage range on a ±15V supply. The inputs are fault protected from common mode voltage transients up to ±350V and differential voltages up to ±500V. The LT1990-10 is ideally suited for both high side and low side current or voltage monitoring.On a single 5V supply, the LT1990-10 has an adjustable 85V input range, 60dB min CMRR and draws less than 180µA supply current. The rail-to-rail output maximizes the dynamic range, especially important for single supplies as low as 2.7V.The LT1990-10 is specified for single 3V, 5V and ±15V supplies over the industrial temperature range.The LT1990-10 is available in the 8-pin SO and pin FMEA compatible MSOP packages.ApplicationsBattery Cell Voltage MonitoringHigh Voltage Current SensingSignal Acquisition in Noisy EnvironmentsInput ProtectionFault Protected Front EndsLevel SensingIsolation