LM3370 Datasheet, PDF (1/33 Pages) National Semiconductor (TI) – Dual Synchronous Step-Down DC-DC Converter with Dynamic Voltage Scaling Function

LM3370
www.ti.com
SNVS406M – NOVEMBER 2005 – REVISED AUGUST 2011
LM3370 Dual Synchronous Step-Down DC-DC Converter with Dynamic Voltage Scaling
Function
Check for Samples: LM3370
FEATURES
1
•2 I²C-compatible interface
– V_OUT1 = 1V to 2V in 50 mV steps
– V_OUT2 = 1.8V to 3.3V in 100 mV steps
– Automatic PFM/PWM mode switching &
Forced PWM mode for low noise operation
– Spread Spectrum capability using I²C
• 600 mA load per channel
• 2 MHz PWM fixed switching frequency (typ.)
• The Bucks operate 180° out-of-phase timing
offset for noise and input surge current
abatement
• Internal synchronous rectification for high
efficiency
• Internal soft start
• Power-on-reset function for both outputs
• 2.7V ≤ V_IN ≤ 5.5V
• Operates from a single Li-Ion cell or 3 cell
NiMH/NiCd batteries and 3.3V/5.5V fixed rails
• 2.2 µH Inductor, 4.7 µF Input and 10 µF Output
Capacitor per channel
• 16-lead LLP Package (4 mm x 5 mm x 0.8 mm)
• 20-bump micro SMD Package (3.0 mm x 2.0
mm x 0.6 mm)
APPLICATIONS
• Baseband Processors
• Application Processors (Video, Audio)
• I/O Power
• FPGA Power and CPLD
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
output voltage range varies from 1V to 3.3V and can be dynamically controlled using the I²C-compatible
interface. This dynamic voltage scaling function allows processors to achieve maximum performance at the
lowest power level. The I²C-compatible interface can also be used to control auto PFM-PWM/PWM mode
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.
1
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2
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2005–2011, Texas Instruments Incorporated