LM3670MF-18 Datasheet, PDF (1/25 Pages) Texas Instruments – LM3670 Miniature Step-Down DC-DC Converter for Ultra Low Voltage Circuits

LM3670
www.ti.com
SNVS250E – NOVEMBER 2004 – REVISED FEBRUARY 2013
LM3670 Miniature Step-Down DC-DC Converter for Ultra Low Voltage Circuits
Check for Samples: LM3670
FEATURES
1
•2 V_OUT = Adj (0.7V min), 1.2, 1.5, 1.6, 1.8, 1.875,
2.5, 3.3V
• 2.5V ≤ V_IN ≤ 5.5V
• 15 µA Typical Quiescent Current
• 350 mA Maximum Load Capability
• 1 MHz PWM Fixed Switching Frequency (typ.)
• Automatic PFM/PWM Mode Switching
• Available in Fixed Output Voltages as well as
an Adjustable Version
• SOT-23-5 Package
• Low Drop Out Operation - 100% Duty Cycle
Mode
• Internal Synchronous Rectification for High
Efficiency
• Internal Soft Start
• 0.1 µA Typical Shutdown Current
• Operates from a Single Li-Ion Cell or 3 Dell
NiMH/NiCd Batteries
• Only Three Tiny Surface-Mount External
Components Required (One Inductor, Two
Ceramic Capacitors)
• Current Overload Protection
APPLICATIONS
• Mobile Phones
• HandHeld
• PDAs
• Palm-Top PCs
• Portable Instruments
• Battery Powered Devices
DESCRIPTION
The LM3670 step-down DC-DC converter is
optimized for powering ultra-low voltage circuits from
a single Li-Ion cell or 3 cell NiMH/NiCd batteries. It
provides up to 350 mA load current, over an input
voltage range from 2.5V to 5.5V. There are several
different fixed voltage output options available as well
as an adjustable output voltage version.
The device offers superior features and performance
for mobile phones and similar portable applications
with complex power management systems. Automatic
intelligent switching between PWM low-noise and
PFM low-current mode offers improved system
control. During full-power operation, a fixed-frequency
1 MHz (typ). PWM mode drives loads from ∼70 mA to
350 mA max, with up to 95% efficiency. Hysteretic
PFM mode extends the battery life through reduction
of the quiescent current to 15 µA (typ) during light
current loads and system standby. Internal
synchronous rectification provides high efficiency (90
to 95% typ. at loads between 1 mA and 100 mA). In
shutdown mode (Enable pin pulled low) the device
turns off and reduces battery consumption to 0.1 µA
(typ.).
Typical Application
V_IN
2.5V to 5.5V
C_IN
4.7uF
V_{IN 1}
L1:10uH
5 ^SW
LM3670
GND
2
V_OUT
C_OUT
10uF
EN ₃
FB
4
Figure 1. Fixed Output Voltage
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.
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