Analog Devices

The LT8627SP synchronous step-down regulator features third-generation Silent Switcher technology which is uniquely designed to combine an ultralow noise reference with Silent Switcher architecture in order to achieve both high efficiency and excellent wideband noise performance.The innovative ultralow noise architecture provides exceptional low frequency (0.1Hz to 100kHz) output noise performance in a switching regulator. The output voltage can be programmed with a single resistor, resulting in virtually constant output noise independent of output voltage.Silent Switcher architecture minimizes EMI emissions while delivering high efficiency at high switching frequencies. The top of the package features exposed die for optional heat sink attachment which can be used to significantly improve thermal performance.The LT8627SP is ideal for high current, noise sensitive applications which benefit from the high efficiency of a synchronous switching regulator.Note: The LT8627SP is pin-to-pin compatible with the LT8625SP-1.ApplicationsRF Power Suppliers: PLLs, VCOs, Mixers, LNAs, PAsHigh Speed/High Precision ADCs/DACsLow Noise Instrumentation

The LT8631 is a current mode PWM step-down DC/DC converter with internal synchronous switches that provide current for output loads up to 1A. The wide input range of 3V to 100V makes the LT8631 suitable for regulating power from a wide variety of sources, including automotive and industrial systems and 36V to 72V telecom supplies. Low ripple Burst Mode operation enables high efficiency operation down to very low output currents while keeping the output ripple below 10mVP-P. Resistor programmable 100kHz to 1MHz frequency range and synchronization capability enable optimization between efficiency and external component size. The soft-start feature controls the ramp rate of the output voltage, eliminating input current surge during start-up, while also providing output tracking. A power good flag signals when the output voltage is within ±7.5% of the regulated output. Undervoltage lockout can be programmed using the EN/UV pin. Shutdown mode reduces the total quiescent current to < 5μA. The LT8631 is available in a 20-lead TSSOP package with exposed pad for low thermal resistance and high voltage lead spacing.APPLICATIONSTelecom SuppliesDistributed Supply Regulation

TheLT8636/LT8637 synchronous step-down regulator features Silent Switcher architecture designed to minimize EMI emissions while delivering high efficiency at high switching frequencies. Peak current mode control with a 30ns minimum on-time allows high step-down ratios even at high switching frequencies.The LT8636’s ultralow 2.5µA quiescent current—with the output in full regulation—enables applications requiring highest efficiency at very small load currents. The LT8637 has external compensation to enable current sharing and fast transient response at high switching frequencies. A CLKOUT pin enables synchronizing other regulators to the LT8636/LT8637.Burst Mode operation enables ultralow standby current consumption, forced continuous mode can control frequency harmonics across the entire output load range, or spread spectrum operation can further reduce EMI emissions. Soft-start and tracking functionality is accessed via the TR/SS pin, and an accurate input voltage UVLO threshold can be set using the EN/UV pin.APPLICATIONSAutomotive and Industrial SuppliesGeneral Purpose Step-Down

The LT8638S synchronous step-down regulator features second generation Silent Switcher architecture designed to minimize EMI emissions while delivering high efficiency at high switching frequencies. This includes the integration of input capacitors to optimize all the fast current loops inside and make it easy to achieve advertised EMI performance by reducing layout sensitivity. This performance makes the LT8638S ideal for noise sensitive applications and environments.The fast, clean, low overshoot switching edges enable high efficiency operation even at high switching frequencies, leading to a small overall solution size. Peak current mode control with a 25ns minimum on-time allows high step down ratios even at high switching frequencies. External compensation via the VCpin allows for fast transient response. PolyPhase operation allows multiple LT8638S regulators to run with interleaving phase shift to provide more output current.Burst Mode operation enables low standby current consumption, forced continuous mode can control frequency harmonics across the entire output load range, or spread spectrum operation can further reduce EMI emissions. Soft-start and tracking functionality is accessed via the SS pin, and an accurate input voltage UVLO threshold can be set using the EN/UV pin.ApplicationsAutomotive and Industrial SuppliesGeneral Purpose Step-Down

The LT8640A step-down regulator features Silent Switcher architecture designed to minimize EMI emissions while delivering high efficiency at frequencies up to 3MHz. An ultralow 2.5μA quiescent current—with the output in full regulation—enables applications requiring highest efficiency at very small load currents.The LT8640A allows high VINto low VOUTconversion at high frequency with a fast minimum top switch on-time of 30ns. The SYNC/MODE pin selects between Burst Mode operation, spread spectrum mode, synchronization to an external clock, and forced continuous mode.ApplicationsAutomotive and Industrial SuppliesGeneral Purpose Step-Down

The LT8640/LT8640-1 step-down regulator features Silent Switcher architecture designed to minimize EMI emissions while delivering high efficiency at frequencies up to 3MHz. An ultralow 2.5µA quiescent current—with the output in full regulation—enables applications requiring highest efficiency at very small load currents.The LT8640/LT8640-1 allows high VINto low VOUTconversion at high frequency with a fast minimum top switch on-time of 30ns. The SYNC/MODE pin selects between Burst Mode operation, spread spectrum mode, synchronization to an external clock, and either pulse-skipping (LT8640) or forced continuous mode (LT8640-1).PackageSYNC/MODE ≠ 0VCCOMPH-GRADECLKOUTINTERNAL CAPSLT8640QFNPulse-SkippingInternalYesNoNoLT8640-1QFNFCMInternalYesNoNoLT8640SLQFNFCMInternalNoYesYesLT8643SLQFNFCMExternalNoYesYesLT8640S-2LQFNFCMInternalYesYesNoLT8643S-2LQFNFCMExternalYesYesNoApplicationsAutomotive and Industrial SuppliesGeneral Purpose Step-DownGSM Power Supplies

The LT®8640S/LT8643S/LT8640SA/LT8643SA synchronous step-down regulator features second generation Silent Switcher architecture designed to minimize EMI emissions while delivering high efficiency at high switching frequencies. This includes the integration of bypass capacitors to optimize all the fast current loops inside and make it easy to achieve advertised EMI performance by reducing layout sensitivity. This performance makes the LT8640S/LT8643S/LT8640SA/LT8643SA ideal for noise-sensitive applications and environments.Peak current mode control with a 30ns minimum on-time allows high step-down ratios even at high switching frequencies. The LT8643S/LT8643SA has external compensation to enable current sharing and fast transient response at high switching frequencies.Burst Mode operation enables ultralow standby current consumption, forced continuous mode can control frequency harmonics across the entire output load range, or spreadspectrum operation can further reduce EMI emissions.ApplicationsAutomotive and Industrial Supplies

The LT8641 step-down regulator features Silent Switcher architecture designed to minimize EMI/EMC emissions while delivering high efficiency at frequencies up to 3MHz. Assembled in a 3mm × 4mm QFN, the monolithic construction with integrated power switches and inclusion of all necessary circuitry yields a solution with a minimal PCB footprint. An ultralow 2.5μA quiescent current—with the output in full regulation—enables applications requiring highest efficiency at very small load currents. Transient response remains excellent and output voltage ripple is below 10mVP-Pat any load, from zero to full current.The LT8641 allows high VINto low VOUTconversion at high frequency with a fast minimum top switch on-time of 35ns. Operation is safe in overload even with a saturated inductor.Essential features are included and easy to use: An open-drain PG pin signals when the output is in regulation. The SYNC/MODE pin selects between Burst Mode, pulse-skipping, or spread spectrum mode, and also allows synchronization to an external clock. Soft-start and tracking functionality is accessed via the TR/SS pin. An accurate enable threshold can be set using the EN/UV pin and a resistor at the RT pin programs switch frequency.APPLICATIONSAutomotive and Industrial SuppliesGeneral Purpose Step-DownGSM Power Supplies

The LT8642-1 synchronous step-down regulator features Silent Switcher architecture designed to minimize EMI emissions while delivering high efficiency at high switching frequencies. This performance makes the LT8642-1 ideal for noise sensitive applications and environments.The fast, clean, low-overshoot switching edges enable high efficiency operation even at high switching frequencies, leading to a small overall solution size. Peak current mode control with a 20ns minimum on-time allows high step-down ratios even at high switching frequencies. External compensation via the VCpin allows for fast transient response at high switching frequencies. The VCpin also enables current sharing and a CLKOUT pin enables synchronizing other regulators to the LT8642-1.Burst Mode operation enables low standby current consumption, forced continuous mode can control frequency harmonics across the entire output load range, or spread spectrum operation can further reduce EMI emissions. Soft-start and tracking functionality is accessed via the SS pin, and an accurate input voltage UVLO threshold can be set using the EN/UV pin.APPLICATIONSServer Power ApplicationsAutomotive and Industrial SuppliesGeneral Purpose Step-DownINTERNAL CAPACITORSPACKAGELT8642SVIN, BST, INTVCC4mm × 4mm LQFNLT8642-1None3mm × 4mm LQFN

The LT8642S synchronous step-down regulator features second generation Silent Switcher architecture designed to minimize EMI emissions while delivering high efficiency at high switching frequencies. This includes the integration of bypass capacitors to optimize all the fast current loops inside and make it easy to achieve advertised EMI performance by eliminating layout sensitivity.The fast, clean, low-overshoot switching edges enable high efficiency operation even at high switching frequencies, leading to a small overall solution size. Peak current mode control with a 20ns minimum on-time allows high step down ratios even at high switching frequencies. External compensation via the VCpin allows for fast transient response at high switching frequencies. A CLKOUT pin enables synchronizing other regulators to the LT8642S.Burst Mode operation enables low standby current consumption, forced continuous mode can control frequency harmonics across the entire output load range, or spread spectrum operation can further reduce EMI emissions. Soft-start and tracking functionality is accessed via the SS pin, and an accurate input voltage UVLO threshold can be set using the EN/UV pin.APPLICATIONSServer Power ApplicationsAutomotive and Industrial SuppliesGeneral Purpose Step-Down