LTC3541-2 Series

High Efficiency Buck + VLDO Regulator

Catalog

High Efficiency Buck + VLDO Regulator

Part	Voltage/Current - Output 2 [Min]	Voltage/Current - Output 2	Voltage/Current - Output 2 [Max]	Operating Temperature [Max]	Operating Temperature [Min]	Voltage/Current - Output 1 [Min]	Voltage/Current - Output 1 [Max]	Voltage/Current - Output 1	Supplier Device Package	Voltage - Supply [Min]	Voltage - Supply [Max]	Topology	Frequency - Switching	Mounting Type	Number of Outputs	Package / Case	Voltage/Current - Output 3 [custom]	Voltage/Current - Output 3 [custom]
Analog Devices LTC3541EDD-3#PBF	0.4 V	300 mA	4.1 V	85 °C	-40 °C	0.8 V	5 V	500 mA	10-DFN (3x3)	0.9 V	5.5 V	Linear (LDO) (1) Step-Down (Buck) Synchronous (1)	2.25 MHz	Surface Mount	2	10-WFDFN Exposed Pad
Analog Devices LTC3541EDD-1#PBF	0.4 V	300 mA	4.1 V	85 °C	-40 °C	0.8 V	5 V	500 mA	10-DFN (3x3)	0.9 V	5.5 V	Linear (LDO) (1) Step-Down (Buck) Synchronous (1)	2.25 MHz	Surface Mount	2	10-WFDFN Exposed Pad
Analog Devices LTC3541EDD-3#PBF	0.4 V	300 mA	4.1 V	85 °C	-40 °C	0.8 V	5 V	500 mA	10-DFN (3x3)	0.9 V	5.5 V	Linear (LDO) (1) Step-Down (Buck) Synchronous (1)	2.25 MHz	Surface Mount	2	10-WFDFN Exposed Pad
Analog Devices LTC3541EDD-2#TRPBF	0.4 V	300 mA	4.1 V	85 °C	-40 °C	0.8 V	5 V	500 mA	10-DFN (3x3)	0.9 V	5.5 V	Linear (LDO) (1) Step-Down (Buck) Synchronous (1)	2.25 MHz	Surface Mount	2	10-WFDFN Exposed Pad
Analog Devices LTC3541EDD#TRPBF	0.4 V	300 mA	4.1 V	85 °C	-40 °C	0.8 V	5 V	500 mA	10-DFN (3x3)	0.9 V	5.5 V	Linear (LDO) (1) Step-Down (Buck) Synchronous (1)	2.25 MHz	Surface Mount	2	10-WFDFN Exposed Pad
Analog Devices LTC3541EDD-1#TRPBF	0.4 V	300 mA	4.1 V	85 °C	-40 °C	0.8 V	5 V	500 mA	10-DFN (3x3)	0.9 V	5.5 V	Linear (LDO) (1) Step-Down (Buck) Synchronous (1)	2.25 MHz	Surface Mount	2	10-WFDFN Exposed Pad
Analog Devices LTC3541EDD-2#PBF	0.4 V	300 mA	4.1 V	85 °C	-40 °C	0.8 V	5 V	500 mA	10-DFN (3x3)	0.9 V	5.5 V	Linear (LDO) (1) Step-Down (Buck) Synchronous (1)	2.25 MHz	Surface Mount	2	10-WFDFN Exposed Pad
Analog Devices LTC3541EDD-1#PBF				85 °C	-40 °C				10-DFN (3x3)	0.9 V	5.5 V	Linear (LDO) (1) Step-Down (Buck) Synchronous (1)	2.25 MHz	Surface Mount	2	10-WFDFN Exposed Pad	Adjustable	Adjustable

Catalog

High Efficiency Buck + VLDO Regulator

Key Features

• High Efficiency, 500mA Buck Plus 300mA VLDO™Regulator

• Auto Start-Up Powers VLDO/Linear Regulator Output Prior to Buck Regulator Output

• Independent High Efﬁciency, 500mA Buck (VIN: 2.7V to 5.5V)

• 300mA VLDO Regulator with 30mA Standalone Mode

• No External Schottky Diodes Required

• Buck Output Voltage Range: 0.8V to 5V

• VLDO Input Voltage Range (LVIN): 0.9V to 5.5V

• VLDO Output Voltage Range VLDO: 0.4V to 4.1V

• Selectable Fixed Frequency, Pulse-Skip Operation or Burst Mode®Operation

• Short-Circuit Protected

• Current Mode Operation for Excellent Line and Load Transient Response

• Constant Frequency Operation: 2.25MHz

• Low Dropout Buck Operation: 100% Duty Cycle

• Small, Thermally Enhanced, 10-Lead (3mm × 3mm) DFN Package

Description

The LTC3541-1 combines a synchronous buck DC/DC converter with a very low dropout linear regulator (VLDO) to provide up to two output voltages from a single input voltage with minimal external components. When configured for dual output operation, the LTC3541-1’s auto start-up feature will bring the VLDO/linear regulator output into regulation in a controlled manner prior to enabling the Buck regulator output without the need for external pin control. Buck output prior to VLDO/linear regulator output sequencing may also be obtained via external pin control. The input voltage range is ideally suited for Li-Ion battery-powered applications, as well as powering sub-3.3V logic from 5V or 3.3V rails.The synchronous buck converter provides a high efficiency output, typically 90%, capable of providing up to 500mA of continuous output current while switching at 2.25MHz, allowing the use of small surface mount inductors and capacitors. A mode-select pin allows Burst Mode operation to be enabled for higher efficiency at light load currents, or disabled for lower noise, constant frequency operation.The VLDO regulator provides a low noise, low voltage output capable of providing up to 300mA of continuous output current using only a 2.2µF ceramic capacitor. The input supply voltage of the VLDO regulator (LVIN) may come from the buck regulator or a separate supply.OptionsVOUTSwitcher (V)VOUTVLDOAuto Start-Up SequencingLTC3541Adj. down to 0.8VAdj. down to 0.4VSwitcher, then VLDOLTC3541-1Adj. down to 0.8VAdj. down to 0.4VVLDO, then switcherLTC3541-21.875V fixed1.5V fixedSwitcher, then VLDOLTC3541-31.8V fixed1.575V fixedVLDO, then switcherApplicationsPDAs/Palmtop PCsDigital CamerasCellular PhonesPC CardsWireless and DSL ModemsOther Portable Power Systems