LM3679 DC-DC Converter Datasheet

LM3679 Datasheet, PDF, Equivalent


Part Number

LM3679

Description

350mA Miniature Step-Down DC-DC Converter

Manufacture

etcTI

Total Page 25 Pages
Datasheet
Download LM3679 Datasheet


LM3679
LM3679
www.ti.com
SNVS510A – SEPTEMBER 2007 – REVISED FEBRUARY 2008
LM3679 3MHz, 350mA Miniature Step-Down DC-DC Converter for Ultra Low Profile
Applications (Height < 0.55mm)
Check for Samples: LM3679
FEATURES
1
2 16 µA Typical Quiescent Current
• 350 mA Maximum Load Capability
• 3 MHz PWM Fixed Switching Frequency (typ)
• Automatic PFM/PWM Mode Switching
• Available in 5-Bump DSBGA YZR Package and
YPD Package
• Internal Synchronous Rectification for High
Efficiency
• Internal Soft Start
• 0.01 µA Typical Shutdown Current
• Operates from a Single Li-Ion Cell Battery
• Current Overload and Thermal Shutdown
Protection
• Three External Components Required for
Typical Applications
• Low Profile Solution (0.55mm Max Height,
Includes Four External Components)
APPLICATIONS
• Mobile Phones
• PDAs
• MP3 Players
• W-LAN
• Portable Instruments
• Digital Still Cameras
• Portable Hard Disk Drives
DESCRIPTION
The LM3679 step-down DC-DC converter is
optimized for powering ultra-low voltage circuits from
a single Li-Ion cell battery and input voltage rails from
2.5V to 5.5V. It provides up to 350mA load current,
over the entire input voltage range. The LM3679
output voltage can be configured to 1.2V, 1.5V, or
1.8V.
TYPICAL APPLICATION CIRCUIT
VIN
2.5V to 5.5V
CIN
4.7 PF
VIN 1
L1: 1.0 PH
5 SW
LM3679
GND 2
EN 3
4 FB
VOUT
COUT
10 PF
Bill of Materials for Low Profile Solution:
CIN = JMK107BJ475K (Taiyo - Yuden)
COUT = JMK107BJ475K (Taiyo - Yuden) x2
Inductor = LQM21PN1R0MC0 (MuRata)
Figure 1. Typical Low Profile Application Circuit
(0.55mm max height using LM3679UR)
Figure 2. Efficiency vs. Output Current (VOUT =
1.8V)
1
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
All trademarks are the property of their respective owners.
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 © 2007–2008, Texas Instruments Incorporated

LM3679
LM3679
SNVS510A – SEPTEMBER 2007 – REVISED FEBRUARY 2008
www.ti.com
DESCRIPTION CONTINUED
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 PWM mode operation, the device operates at a fixed-
frequency of 3 MHz (typ). PWM mode drives loads from ~ 80mA to 350mA max. Hysteretic PFM mode extends
the battery life by reducing the quiescent current to 16 µA (typ) during light load and standby operation. Internal
synchronous rectification provides high efficiency. In shutdown mode (Enable pin pulled low), the device turns off
and reduces battery consumption to 0.01 µA (typ).
The LM3679 is available in a lead-free (No PB) 5-bump DSBGA YZR package, 0.6mm height, and in an ultra thin
0.3mm height YPD package. Using the YPD package along with specific external components, allows for a low
profile solution size with a max height of 0.55mm. A switching frequency of 3 MHz (typ) allows use of tiny
surface-mount components. Only three external surface-mount components, an inductor and two ceramic
capacitors, are required. .
CONNECTION DIAGRAM AND PACKAGE MARK INFORMATION
Vin A1
A3 GND
GND
A3
A1 Vin
B2 SW
SW B2
EN C1
C3 FB
FB C3
C1 EN
Top View
Bottom View
Figure 3. 5 Bump DSBGA YZR and YPD Package (YPD package to be released soon)
Pin #
A1
A3
C1
C3
B2
Name
VIN
GND
EN
FB
SW
PIN DESCRIPTIONS
Description
Power supply input. Connect to the input filter capacitor (Figure 1).
Ground pin.
Enable pin. The device is in shutdown mode when voltage to this pin is <0.4V and enabled
when >1.0V. Do not leave this pin floating.
Feedback analog input. Connect directly to the output filter capacitor (Figure 1).
Switching node connection to the internal PFET switch and NFET synchronous rectifier.
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
2 Submit Documentation Feedback
Product Folder Links: LM3679
Copyright © 2007–2008, Texas Instruments Incorporated


Features LM3679 www.ti.com SNVS510A – SEPTEMB ER 2007 – REVISED FEBRUARY 2008 LM36 79 3MHz, 350mA Miniature Step-Down DC-D C Converter for Ultra Low Profile Appli cations (Height < 0.55mm) Check for Sam ples: LM3679 FEATURES 1 •2 16 µA Ty pical Quiescent Current • 350 mA Maxi mum Load Capability • 3 MHz PWM Fixed Switching Frequency (typ) • Automati c PFM/PWM Mode Switching • Available in 5-Bump DSBGA YZR Package and YPD Pac kage • Internal Synchronous Rectifica tion for High Efficiency • Internal S oft Start • 0.01 µA Typical Shutdown Current • Operates from a Single Li- Ion Cell Battery • Current Overload a nd Thermal Shutdown Protection • Thre e External Components Required for Typi cal Applications • Low Profile Soluti on (0.55mm Max Height, Includes Four Ex ternal Components) APPLICATIONS • Mo bile Phones • PDAs • MP3 Players W-LAN • Portable Instruments • Di gital Still Cameras • Portable Hard D isk Drives DESCRIPTION The LM3679 step-down DC-DC converter is optimized for powering ultra-low voltage cir.
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