Analog Devices Inc./Maxim Integrated

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 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 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