LM3678_15 Datasheet, PDF (1/19 Pages) Texas Instruments – High-Performance Miniature 1.5-A Step-Down DC-DC Converter for Handheld Applications

LM3678
www.ti.com
SNVS464C – APRIL 2008 – REVISED MAY 2013
High-Performance Miniature 1.5-A Step-Down DC-DC Converter for Handheld Applications
Check for Samples: LM3678
FEATURES
1
•2 V_OUT = 0.8 V or 1.2 V
• V_IN = 2.5 V to 5.5 V
• 1.5-A Maximum Load Capability
• 3.3-MHz (Typical) PWM Fixed Switching
Frequency Allows Use of 1-µH Inductor
• ±3% DC Output Voltage Precision
• 0.01-µA (Typical) Shutdown Current
• Internal Synchronous Rectification for High
Efficiency
• Internal Soft Start
• Current Overload and Thermal Shutdown
Protection
APPLICATIONS
• PDAs and Smart Phones
• Personal Media Players
• W-LAN
• USB Modem Applications
• Digital Still Cameras
• Portable Hard Disk Drives
DESCRIPTION
The LM3678 step-down DC-DC converter is
optimized for powering low-voltage circuits from a
single Li-Ion cell battery and input voltage rails from
2.5 V to 5.5 V. It provides up to 1.5-A load current,
over the entire input voltage range. LM3678 offers a
0.8V or 1.2V option. One of the pair of voltages is set
through the VSELECT pin.
LM3678 operates in PWM mode with a fixed
frequency of 3.3 MHz. Internal synchronous
rectification provides high efficiency during PWM
mode operation. In shutdown mode, the device turns
off and reduces battery consumption to 0.01 µA
(typical).
The LM3678 is available in a 3mm x 3mm DSC-10
package. A high switching frequency of 3.3 MHz
(typical) allows use of tiny surface-mount
components. Only three external surface-mount
components, an inductor and two ceramic capacitors,
are required (solution size less than 33 mm²). For
voltages other than the voltage shown, contact TI or
your distributor.
VIN = 2.5V to 5.5V
CIN 10 PF
Typical Application Circuit
VDD
VDD
1 PH
SW
FB
COUT
EN
PWM
LM3678
0.8V/1.2V
VSELECT
GND
PGOOD
GND
VOUT
22 PF
NOTE: V_SEL H = 1.2V, V_SEL L = 0.8V
Efficiency vs. Output Current
( V_OUT = 1.2V)
V_IN = 2.5V, 2.7V
90
80
70
60
V_IN = 3.6V
50
40
30
V_IN = 4.5V
20
10
0
V_IN = 5.5V
Figure 1.
0.010
0.100
1.000
LOAD (A)
Figure 2.
10.000
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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