SGM41280A
Wide Input Range
Boost Converter with Bypass Switch
MARCH 2020 – RE V. A
SG Micro Corp
www.sg-micro.com
GENERAL DESCRIPTION
The SGM41280A is a wide input range front-end
DC/DC synchronous boost converter with a bypass
switch designed to efficiently connect a battery voltage
source to the power rail of a system. It is typically used
in portable applications such as smart phones or
tablets. Five preset voltages can be programmed for
the output by applying pulse patterns on the VS input
pin.
The SGM41280A has two main bypass modes (active
and passive) to directly connect the load to the V
IN
source. In the active bypass mode, the direct
connection is made through a supplementary bypass
switch when V
IN
is above the programmed V
OUT
,
otherwise a boost converter regulates the load voltage
rail at the programmed value. The low input voltage
may occur due to the increased load current or battery
low charge state. When the input voltage is high, the
boost converter is turned off and the input is directly
bypassed to the output by the bypass switch, resulting
in a very small drop between input and output. In the
passive bypass mode, only the top switch of the boost
converter is kept on providing the bypass route along
with the series input inductor. In this mode, the path
resistance is relatively higher, but the device consumes
a very small quiescent current (I
Q
). Most of the internal
circuits including the boost and protection blocks are off
to minimize power consumption. Therefore, in passive
bypass mode, V
OUT
can drop below programmed value
as it follows V
IN
. The SGM41280A is an enhanced
version of the SGM41280, with the passive bypass
mode added for improved lower loss performance.
This device can be shut down by VS pin to disconnect
the output and minimize quiescent current. It is still
programmable by VS pin when it is shut down and can
go back to the previous bypass mode or to a new
setting.
The boost runs at 2.5MHz but the frequency drops at
light load when converter uses PSM for power-saving.
The SGM41280A is available in Green WLCSP-
1.27×1.67-12B and TQFN-3×3-16L packages and can
operate over -40℃ to +85℃ ambient temperature
range.
FEATURES
● Wide Input Voltage Range from 2.0V to 4.9V
● 3.85V/3.0A Continuous Output at 3.4V Input
● 95% Efficiency at 2.5MHz PWM Frequency
● Simple I/O Control Interface
● Programmable Output Voltages:
3.35V/3.45V/3.63V/3.85V (Default)/4.25V
●
I
Q
= 10μA, R
DS(ON)
= 20m
Ω
in Active Bypass Mode
● I
Q
< 1μA, R
DS(ON)
= 40m
Ω
in Passive Bypass Mode
● Less than 1
μ
A Shutdown Current
● Thermal Shutdown Protection
● Valley Current Limit Protection
● Seamless Transition between Boost Mode and
Active Bypass Mode
● Internal Soft-Start
●
-40
℃
to +85
℃
Operating Temperature Range
● Available in Green WLCSP-1.27×1.67-12B and
TQFN-3×3-16L Packages
APPLICATIONS
Smart-Phones
Tablet PCs
Portable Electronic Equipment
Brownout Prevention with High Power Loads
TYPICAL APPICATION CIRCUIT
Figure 1. Typical Application Circuit
VIN
SW VOUT
VS
PGND AGND
C
IN
= 2 × 10μF
C
OUT
= 4 × 10μF
Battery: 2.0V ~ 4.35V
Outputs:
3.35V/3.45V/3.63V/
3.85V(Default)/4.25V
L = 0.47μH
SGM41280A
One Wire: enable and set output voltage
GND
Wide Input Range
SGM41280A Boost Converter with Bypass Switch
2
MARCH 2020
SG Micro Corp
www.sg-micro.com
PACKAGE/ORDERING INFORMATION
MODEL
PACKAGE
DESCRIPTION
SPECIFIED
TEMPERATURE
RANGE
ORDERING
NUMBER
PACKAGE
MARKING
PACKING
OPTION
SGM41280A
WLCSP-1.27×1.67-12B
-40℃ to +85℃
SGM41280AYG/TR
XXXX
CB0
Tape and Reel, 3000
TQFN-3×3-16L
-40℃ to +85℃
SGM41280AYTQ16G/TR
CB1TQ
XXXXX
Tape and Reel, 4000
MARKING INFORMATION
NOTE: XXXX = Date Code. XXXXX = Date Code and Vendor Code.
Date Code - Week
Date Code - Year
X XX X
Date Code - Week
Vendor Code
Date Code - Year
X XXX X
Green (RoHS & HSF): SG Micro Corp defines "Green" to mean Pb-Free (RoHS compatible) and free of halogen substances. If
you have additional comments or questions, please contact your SGMICRO representative directly.
ABSOLUTE MAXIMUM RATINGS
VIN, SW, VOUT to GND ....................................... -0.3V to 6V
VS to GND ................................................ -0.3V to V
IN
+ 0.3V
Package Thermal Resistance
WLCSP-1.27×1.67-12B, θ
JA
...................................... 90℃/W
TQFN-3×3-16L, θ
JA
.................................................... 50℃/W
Junction Temperature ................................................. +150℃
Storage Temperature Range ........................ -65℃ to +150℃
Lead Temperature (Soldering, 10s) ............................ +260℃
ESD Susceptibility
HBM ............................................................................. 4000V
CDM ............................................................................ 1000V
RECOMMENDED OPERATING CONDITIONS
Input Voltage Range ........................................... 2.0V to 4.9V
Operating Ambient Temperature Range......... -40℃ to +85℃
Operating Junction Temperature Range ...... -40℃ to +125℃
OVERSTRESS CAUTION
Stresses beyond those listed in Absolute Maximum Ratings
may cause permanent damage to the device. Exposure
to
absolute maximum rating conditions for extended periods
may affect reliability. Functional operation of the device at any
conditions beyond those indicated in the Recommended
Operating Conditions section
is not implied.
ESD SENSITIVITY CAUTION
This integrated circuit can be damaged if ESD protections are
not considered carefully. SGMICRO recommends that all
integrated circuits be handled with appropriate precautions.
Failure
to observe proper handling
and installation procedures
can cause damage. ESD damage can range from subtle
performance
degradation to
complete device failure. Precision
integrated circuits may be more susceptible to damage
because even small parametric changes could cause the
device not to meet the published specifications.
DISCLAIMER
SG Micro Corp reserves the right to make any change in
circuit
design, or specifications
without prior notice.