LM3370

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SNVS406M – NOVEMBER 2005 – REVISED AUGUST 2011

LM3370 Dual Synchronous Step-Down DC-DC Converter with Dynamic Voltage Scaling

Function

Check for Samples: LM3370

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FEATURES

2

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2.7V

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Operates from a single Li-Ion cell or 3 cell

NiMH/NiCd batteries and 3.3V/5.5V fixed rails

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2.2 µH Inductor, 4.7 µF Input and 10 µF Output

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Automatic PFM/PWM mode switching &

Capacitor per channel

Forced PWM mode for low noise operation

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16-lead LLP Package (4 mm x 5 mm x 0.8 mm)

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20-bump micro SMD Package (3.0 mm x 2.0

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600 mA load per channel

mm x 0.6 mm)

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2 MHz PWM fixed switching frequency (typ.)

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The Bucks operate 180° out-of-phase timing

APPLICATIONS

offset for noise and input surge current

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Baseband Processors

abatement

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Application Processors (Video, Audio)

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Internal synchronous rectification for high

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I/O Power

efficiency

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FPGA Power and CPLD

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Internal soft start

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Power-on-reset function for both outputs

DESCRIPTION

The LM3370 is a dual step-down DC-DC converter optimized for powering ultra-low voltage circuits from a single

Li-Ion battery and input rail ranging from 2.7V to 5.5V. It provides two outputs with 600 mA load per channel. The

interface. This dynamic voltage scaling function allows processors to achieve maximum performance at the

selection and other performance enhancing features.

The LM3370 offers superior features and performance for portable systems with complex power management

requirements. Automatic intelligent switching between PWM low-noise and PFM low-current mode offers

improved system efficiency. Internal synchronous rectification enhances the converter efficiency without the use

of further external devices.

There is a power-on-reset function that monitors the level of the output voltage to avoid unexpected power

losses. The independent enable pin for each output allows for simple and effective power sequencing.

LM3370 is available in a 4 mm by 5 mm 16-lead non-pullback LLP and a 20-bump micro SMD, 3.0 mm x 2.0 mm

x 0.6 mm, package. A high switching frequency—2 MHz (typ)—allows use of tiny surface-mount components

including a 2.2 µH inductor.

Default fixed voltages for the 2 output voltages combination can be customized to fit system requirements by

contacting National Semiconductor Corporation.

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Products conform to specifications per the terms of the Texas

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