Preliminary Datasheet
LP6252
High Efficiency 2.7A Synchronous Boost Convertor
General Description
The LP6252 is a Synchronous current mode boost
DC-DC converter. Its PWM circuitry with built-in 2.7A
Current power MOSFET makes this converter highly
power efficiently. Selectable high switching frequency
allows faster loop response and easy filtering with a
low noise output. The non-inverting input its error
amplifier is connected to an internal 800mV precision
reference
voltage.
Current
mode
control
and
compensation network make it easy and flexible to
stabilize the system.
Features
Up to 95% efficiency
Output to Input Disconnect at Shutdown Mode
Shut-down current:<1uA
Output voltage Up to 5.5V
Over Output Voltage Protection
Over Current Protection
Over Temperature Protection
Internal Compensation of Soft-start
1MHz fixed frequency switching
High switch on current:2.7A
Available in SOT23-6 and TDFN-6 Package
Order Information
LP6252
□ □ □
F:
Halogen Free and Pb Free
Package Type
B6: SOT23-6
QV:TDFN-6
Typical Application Circuit
VIN
10uF
2.2uH
VIN
SW
VOUT
33pF
(NC)
5V
68K
10uF*2
13K
LP6252
Applications
Battery products
Host Products
Panel
EN
GND
FB
Marking Information
Device
LP6252B6F
LP6252QVF
Marking
LPS
5VYWX
LPS
5TYW
Marking indication:
Y:Production year W:Production period X:Production batch
TDFN-6
4K/REEL
Package
SOT23-6
Shipping
3K/REEL
LP6252-03
Jul.-2018
Email:
marketing@lowpowersemi.com
www.lowpowersemi.com
Page 1 of 8
Preliminary Datasheet
Absolute Maximum Ratings
Note 1
LP6252
Input and VOUT to GND --------------------------------------------------------------------------------------------------- 6V
Other Pin to GND (FB,EN,SW) ------------------------------------------------------------------------------------------- 6V
Maximum Junction Temperature ----------------------------------------------------------------------------------- 150°C
Operating Ambient Temperature Range (T
A
) --------------------------------------------------------- -40℃ to 85°C
Maximum Soldering Temperature (at leads, 10 sec) --------------------------------------------------------- 260°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress
ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational
sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect
device reliability.
Note 1.
Thermal Information
Maximum Power Dissipation (SOT23-6, PD,T
A
=25℃) ------------------------------------------------------- 0.45W
Thermal Resistance (SOT23-6, J
A
) ---------------------------------------------------------------------------
250℃/W
Maximum Power Dissipation (TDFN-6, PD,T
A
=25℃) ---------------------------------------------------------- 1.2W
Thermal Resistance (TDFN-6, J
A
) --------------------------------------------------------------------------------- 95℃/W
ESD Susceptibility
HBM(Human Body Mode) ----------------------------------------------------------------------------------------------- 2KV
MM(Machine Mode) ------------------------------------------------------------------------------------------------------ 200V
Electrical Characteristics
(V
IN
=3.5V, V
OUT
=5V, C
IN
=10uF, C
OUT
=22uF, L=2.2uH, R
1
=68K, R
2
=13K)
Parameter
Condition
Min
Typ
Max
Units
Supply Voltage
Output Voltage Range
UVLO
Supply Current(Shutdown)
Feedback Voltage
Feedback Input Current
Switching Frequency
Maximum Duty Cycle
EN Input Low Voltage
EN Input High Voltage
Low-side Current Limit
High-side On Resistance
Low-side On Resistance
V
OUT
=3.3V
V
FB
=0.82V
V
EN
=0V,V
IN
=5V
2.5
2.5
1.8
0.05
784
800
50
1000
80
1.4
2.7
3
200
150
90
5.5
5.4
2.4
1
816
V
V
V
uA
mV
nA
KHz
95
0.4
%
V
V
A
mΩ
mΩ
LP6252-03
Jul.-2018
Email:
marketing@lowpowersemi.com
www.lowpowersemi.com
Page 3 of 8
Preliminary Datasheet
Operation Information
The LP6252 uses a synchronous 1MHz fixed
frequency, current-mode regulation architecture to
regulate the output voltage. The LP6252 measures
the output voltage through an external resistive
voltage divider and compares that to the internal
0.8V reference to generate the error voltage to the
inductor current to regulate the output voltage. The
use of current-mode regulation improves transient
response and control loop stability.
When the LP6252 is disable (EN=Low), both power
switches are off. There is no current path from SW to
OUT. Therefore, the output voltage discharges to
ground. When the LP6252 is enabled(EN=High),a
limited start-current charges the output voltage rising
to SW, then the part operates in force PWM mode for
regulating the output voltage to the target value. At
the beginning of each cycle, the N-channel MOSFET
switch is turned on, forcing the inductor current to
rise, The current at the source of the switch is
internally measured and converted to a voltage by
the current sense amplifier. That voltage is compared
to the error voltage. When the inductor current rises
sufficiently, the PWM comparator turns off the switch,
forcing the inductor current to the output capacitor
through the internal P-Channel MOSFET rectifier,
which forces the inductor current to decrease. The
peak inductor current is controlled by the error
voltage. Thus the output voltage controls the inductor
current to satisfy the lode.
Setting the Output Voltage
LP6252
Set the output voltage by selecting the resistive
voltage divider ratio. The voltage divider drops the
output voltage to the 0.8V feedback voltage. Use a
100K resistor for R
2
of the voltage divider. Determine
the high-side resistor R
1
by the equation:
V
OUT
= ( R
1
/ R
2
+ 1 ) x V
FB
Pre-Boost Current and Short Circuit Protect
Initially output voltage is lower than battery voltage,
and the LP6252 enters pre-boost phase. During
pre-boost phase, the internal NMOSFET/PMOSFET
is turned off/on and a constant current is provided
from battery to output until the output voltage close to
the battery voltage. The constant current is limited by
internal controller. If the output short to ground, the
LP6252 also limits the output current to avoid
damage condition
Output Capacitor Selection
For lower output voltage ripple, low-ESR ceramic
capacitors
are
recommended.
The
tantalum
capacitors can be used as well, but the ESR is bigger
than ceramic capacitor. The output voltage ripple
consists of two components: one is the pulsating
output ripple current flows through the ESR, and the
other is the capacitive ripple caused by charging and
discharging.
LP6252-03
Jul.-2018
Email:
marketing@lowpowersemi.com
www.lowpowersemi.com
Page 5 of 8
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