Analog Devices LTC3545

Description

The LTC3545/LTC3545-1 are triple, high efficiency, monolithic synchronous buck regulators using a constant frequency, current mode architecture. The regulators operate independently with separate run pins. The 2.25V to 5.5V input voltage range makes the LTC3545/LTC3545-1 well suited for single Li-Ion battery-powered applications. Low ripple pulse skip mode or high efficiency Burst Mode operation is externally selectable. PWM pulse skip mode operation provides very low output ripple voltage while Burst Mode operation increases efficiency at low output loads.

Switching frequency is internally set to 2.25MHz, or the switching frequency can be synchronized to an external 1MHz to 3MHz clock. Power good indicators easily allow power on sequencing between the three regulators.

The internal synchronous switches increase efficiency and eliminate external Schottky diodes. Low output voltages are supported with the 0.6V feedback reference voltage.

The LTC3545-1 replaces the SYNC/MODE function with a third PGOOD pin and forces Burst Mode operation.

Features

• Three 800mA Outputs
• High Effi ciency: Up to 95%
• 2.25V to 5.5V Input Voltage Range
• Low Ripple (<20mVP-P) Burst Mode® OperationIQ: 58μA
• 2.25MHz Constant Frequency Operation or
• Synchronizable to External 1MHz to 3MHz Clock
• Power Good Indicators Ease Supply Sequencing
• 0.6V Reference Allows Low Output Voltages
• Current Mode Operation/Excellent Transient Response
• Low Profi le 16-Lead 3mm × 3mm QFN Package

Remarks:

• For most applications, the value of the inductor will fall in the range of 1μH to 10μH.

Typical applications

• Wireless and DSL Modems
• Portable Instruments
• Digital Still Cameras
• Point of Load Regulation
• Smart Phones

More information

• Datasheet
• IC product information