Analog Devices

The LTC3616 is a low quiescent current monolithic synchronous buck regulator using a current mode, constant frequency architecture. The no-load DC supply current in sleep mode is only 70μA while maintaining the output voltage (Burst Mode operation) at no load, dropping to zero current in shutdown. The 2.25V to 5.5V input supply voltage range makes the LTC3616 ideally suited for single Li-Ion as well as fixed low voltage input applications. 100% duty cycle capability provides low dropout operation, extending the operating time in battery-powered systems.The operating frequency is externally programmable up to 4MHz, allowing the use of small surface mount inductors. For switching noise-sensitive applications, the LTC3616 can be synchronized to an external clock at up to 4MHz.Forced continuous mode operation in the LTC3616 reduces noise and RF interference. Adjustable compensation allows the transient response to be optimized over a wide range of loads and output capacitors.The internal synchronous switch increases efficiency and eliminates the need for an external catch diode, saving external components and board space. The LTC3616 is offered in a leadless 24-pin 3mm × 5mm thermally enhanced QFN package.ApplicationsPoint-of-Load SuppliesDistributed Power SuppliesPortable Computer SystemsDDR Memory TerminationHandheld Devices

The LTC3617 is a high efficiency monolithic synchronous buck regulator utilizing a current mode, constant frequency architecture. It operates from an input voltage range of 2.25V to 5.5V and provides a regulated output voltage equal to 0.5 • VDDQIN while sourcing and sinking up to 6A of load current. An internal amplifier provides a VTTR output voltage equal to 0.5 • VDDQIN with an output current capability of ±10mA.The operating frequency is externally programmable up to 4MHz, allowing the use of small surface mount inductors. For switching-noise-sensitive applications, the LTC3617 can be synchronized to an external clock up to 4MHz.Forced continuous mode operation in the LTC3617 reduces noise and RF interference. Adjustable external compensation allows the transient response to be optimized over a wide range of loads and output capacitors.The internal synchronous switch increases efficiency and eliminates the need for an external catch diode, minimizing external component count and board space. The LTC3617 is offered in a leadless 24-pin 3mm × 5mm thermally enhanced QFN package.ApplicationsDDR TerminationSupports DDR, DDR2 and DDR3 StandardsTracking Supplies

The LTC3618 is a dual synchronous step-down regulator using a current mode, constant-frequency architecture. It provides a complete DDR solution with an input voltage range from 2.25V to 5.5V.The output of the first step-down regulator offers a high accuracy VDDQsupply. A buffered reference generates VTTR at 50% of VDDQIN and drives loads up to ±10mA. The second regulator generates the DDR termination voltage (VTT) equal to VTTR. Both regulators are capable of delivering ±3A of load current at 1MHz switching frequency.The operating frequency is externally programmable up to 4MHz, allowing the use of small surface mount inductors. 0°, 90°, or 180° of phase shift between the two channels can be selected to minimize input current ripple. For switching noise-sensitive applications, the LTC3618 can be synchronized to an external clock up to 4MHz.The LTC3618 is offered in leadless 24-pin 4mm × 4mm QFN and thermally enhanced 24-pin TSSOP packages.APPLICATIONSDDR MemorySupports DDR, DDR2, and DDR3 StandardsTracking Supplies

The LTC3619B is a dual monolithic synchronous buck regulator using a constant frequency current mode architecture.The input supply voltage range is 2.5V to 5.5V, making it ideal for Li-Ion and USB powered applications. 100% duty cycle capability provides low dropout operation, extending the run time in battery-operated systems. Low output voltages are supported with the 0.6V feedback reference voltage. Channel 1 and channel 2 can supply 400mA and 800mA output current, respectively.The LTC3619B’s programmable average input current limit is ideal for USB applications and for point-of-load power supplies because the LTC3619B’s limited input current will still allow its output to deliver high peak load currents without collapsing the input supply. When the sum of both channels’ currents exceeds the input current limit, channel 2 is current limited while channel 1 remains regulated. The operating frequency is internally set at 2.25MHz allowing the use of small surface mount inductors. Internal soft-start reduces in-rush current during start-up. The LTC3619B is available in small MSOP and 3mm × 3mm DFN packages. The LTC3619B is also available in a low quiescent current, high efficiency Burst Mode®version, LTC3619.Light Load OperationLTC3619Low Ripple Burst Mode (<20mVpp), IQ< 50μALTC3619BPulse Skip (<5mVpp)ApplicationsHigh Peak Load Current ApplicationsUSB Powered DevicesSupercapacitor ChargingRadio Transmitters and Other Handheld Devices

The LTC3620 is a high efficiency, synchronous buck regulator, suitable for very low power, very small footprint applications powered by a single Li-Ion battery.The internal synchronous switches increase efficiency and eliminate the need for external Schottky diodes. Low output voltages are easily supported by the 0.6V feedback reference voltage. The LTC3620-1 option is internally programmed to provide a 1.1V output.The LTC3620 uses a unique variable frequency architecture to minimize power loss and achieve high efficiency. The switching frequency is proportional to the load current, and an internal frequency clamp forces a minimum switching frequency at light loads to minimize noise in the audio range. The user can program the frequency of this clamp by applying an external clock to the FMIN/MODE pin.The battery status output, LOBATB, indicates when the input voltage drops below 3V. To help prevent damage to the battery, an undervoltage lockout (UVLO) circuit shuts down the part if the input voltage falls below 2.8V.The LTC3620 is available in a low profile, 2mm × 2mm 8-lead DFN package.ApplicationsHearing AidsWireless HeadsetsLi-Ion Cell ApplicationsButton Cell Replacement

The LTC3621/LTC3621-2 is a high efficiency 17V, 1A synchronous monolithic step-down regulator. The switching frequency is fixed to 1MHz or 2.25MHz with a ±40% synchronizing range. The regulator features ultralow quiescent current and high efficiencies over a wide VOUTrange.The step-down regulator operates from an input voltage range of 2.7V to 17V and provides an adjustable output range from 0.6V to VINwhile delivering up to 1A of output current. A user-selectable mode input is provided to allow the user to trade off ripple noise for light load efficiency; Burst Mode operation provides the highest efficiency at light loads, while pulse-skipping mode provides the lowest voltage ripple. The MODE pin can also be used to allow the user to sync the switching frequency to an external clock.LTC3621 OptionsPart NameFrequencyVOUTLTC36211.00MHzAdjustableLTC3621-3.31.00MHz3.3VLTC3621-51.00MHz5VLTC3621-22.25MHzAdjustableLTC3621-23.32.25MHz3.3LTC3621-252.25MHz5VAPPLICATIONSPortable-Handheld ScannersIndustrial and Embedded ComputingAutomotive ApplicationsEmergency Radio

The LTC3622 is a dual 1A output, high efficiency synchronous monolithic step-down regulator capable of operating from input supplies up to 17V. The switching frequency is fixed to 1MHz or 2.25MHz with a ±50% synchronization range to an external clock. The regulator features ultralow quiescent current and high efficiency over a wide output voltage range.The step-down regulators operate from an input voltage range of 2.7V to 17V and provide an adjustable output from 0.6V to VIN while delivering up to 1A of output current. A user-selectable mode input is provided to allow the user to trade off ripple noise for light load efficiency. Burst Mode®operation provides the highest efficiency at light loads, while pulse-skipping mode provides the lowest ripple noise. The switching regulators can be synchronized to an external clock. Furthermore, fixed VOUToptions are available to eliminate the external feedback resistors.LTC3622 OptionsPart NameFrequencyVOUTLTC36221.00MHzAdjustableLTC3622-22.25MHzAdjustableLTC3622-23/52.25MHZ5V/3.3VApplicationsBattery Powered SystemsPoint-of-Load SuppliesPortable – Handheld Scanners

The LTC3624/LTC3624-2 is a high efficiency 17V, 2A synchronous monolithic step-down regulator. The switching frequency is fixed to 1MHz (LTC3624) or 2.25MHz (LTC3624-2) with a ±40% synchronization range. The regulator features ultralow quiescent current and high efficiency over a wide VOUTrange.The step-down regulator operates from an input voltage range of 2.7V to 17V and provides an adjustable output range from 0.6V to VINwhile delivering up to 2A of output current. A user-selectable mode input is provided to allow the user to trade off ripple noise for light load efficiency; Burst Mode operation provides the highest efficiency at light loads, while pulse-skipping mode provides the lowest voltage ripple. The MODE pin can also be used to sync the switching frequency to an external clock.LTC3624/LTC3624-2 OptionsPart NumberFrequencyVOUTLTC36241MHzAdjustableLTC3624-3.31MHz3.3VLTC3624-51MHz5VLTC3624-22.25MHzAdjustableLTC3624-23.32.25MHz3.3LTC3624-252.25MHz5VApplicationsBattery Powered EquipmentPortable InstrumentationEmergency RadiosGeneral Purpose Step-Down Supplies

The LTC3625/LTC3625-1 are programmable supercapacitor chargers designed to charge two supercapacitors in series to a fixed output voltage (4.8V/5.3V or 4V/4.5V selectable) from a 2.7V to 5.5V input supply. Automatic cell balancing prevents overvoltage damage to either supercapacitor while maximizing charge rate. No balancing resistors are required.High efficiency, high charging current, low quiescent current and low minimum external parts count (one inductor, one bypass capacitor at VINand one programming resistor) make the LTC3625/LTC3625-1 ideally suited for small form factor backup or high peak power systems.Charging current/maximum input current level is programmed with an external resistor. When the input supply is removed and/or the EN pin is low, the LTC3625/LTC3625-1 automatically enter a low current state, drawing less than 1μA from the supercapacitors.The LTC3625/LTC3625-1 are available in a compact 12‑lead 3mm × 4mm × 0.75mm DFN package.ApplicationsServers, RAID Systems, Mass Storage, High Current Backup SuppliesSolid State Hard DrivesWireless Power MetersHigh Peak Power Boosted Supplies