fitipower integrated technology lnc.
FP6357
High Efficiency 1.5MHz
/a85T
1.2A
Synchronous Step Down Regulator
Description
The FP6357 is a high efficiency, high frequency
synchronous DC-DC step-down converter. The
100% duty cycle feature provides low dropout
operation, extending battery life in portable systems.
The internal synchronous switch increases efficiency
and eliminates the need for external Schottky diode.
At shutdown mode, the input supply current is less
than 1µA.
The current limit protection and on-chip thermal
shutdown features provide protection against any
combination of overload or ambient temperature.
Features
Low R
DS(ON)
for Internal Switch (Top/Bottom):
200/150mΩ
2.5V~5.5V Input Voltage Range
1.2A Output Current
High Efficiency up to 95%
1.5MHz Switching Frequency Minimizes the
External Components
Internal Soft-Start Limits the Inrush Current
Internal Compensation Function
100% Dropout Operation
Power Good Indicator Output (SOT-23-6 only)
RoHS Compliant and Halogen Free
SOT-23-5 and SOT-23-6 Packages
Applications
Set Top Box
LCD TV
Mini-Notebook
Net PC
Pin Assignments
S5 Package (SOT-23-5)
FB
VIN
Ordering Information
FP6357
□□□
TR: Tape/Reel
C: Green
Package Type
S5: SOT-23-5
S6: SOT-23-6
5
4
(Marking)
1
2
3
EN GND LX
S6 Package (SOT-23-6)
FB
PG VIN
SOT-23-5 Marking
Part Number
Product Code
Fi3
FP6357S5CTR
6
5
4
(Marking)
1
2
3
SOT-23-6 Marking
Part Number
Product Code
Fi4
FP6357S6CTR
EN GND LX
Fig
ure 1. Pin Assignment of FP6357
FP6357-Preliminary 0.1-MAY-2013
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fitipower integrated technology lnc.
Typical Application Circuit
OFF ON
FP6357
/a85T
EN
L1
V
IN
C1
R3
PG
PG
GND
VIN
LX
V
OUT
R1
FB
R2
C3
C2
FP6357
(opt.)
Figure 2. Schematic Diagram
V
OUT
3.3V
2.5V
1.8V
1.5V
1.2V
1.05V
C1
4.7μF MLCC
4.7μF MLCC
4.7μF MLCC
4.7μF MLCC
4.7μF MLCC
4.7μF MLCC
R1
453kΩ
316kΩ
200kΩ
150kΩ
100kΩ
75kΩ
R2
100kΩ
100kΩ
100kΩ
100kΩ
100kΩ
100kΩ
L1
μH
μH
1.8μH
1.5μH
1.5μH
1.2μH
C2
10μF MLCC
10μF MLCC
10μF MLCC
10μF MLCC
10μF MLCC
10μF MLCC
Table 1. Recommended Component Values
FP6357-Preliminary 0.1-MAY-2013
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fitipower integrated technology lnc.
Functional Pin Description
Pin Name
EN
GND
LX
VIN
FB
PG
Pin No.
(SOT-23-5)
1
2
3
4
5
--
Pin No.
(SOT-23-6)
1
2
3
4
6
5
Pin Function
FP6357
/a85T
Enable Control. Pull high to turn the IC on, and pull low to disable the IC.
Ground Pin.
Inductor connection to the drains of the internal power MOSFETs.
Power Supply Input Pin. Drive VIN pin by 2.5V to 5.5V voltage to power on the chip.
Voltage Feedback Input Pin. Connect FB and VOUT with a resistive voltage divider. This
IC senses feedback voltage via FB and regulates it at 0.6V.
Open Drain Power Good Output Pin. (SOT-23-6 only)
Block Diagram
PG
(SOT-23-6)
EN
VIN
Power Good
1M
Enable
Control
Undervoltage
Lockout
Bias Supply
Slope Compensation
90%
V
REF
Control Logic
Current Limit
Logic
Control
and
Driver
Logic
1
X
FB
EA
COMP
LX
Compensation
V
REF
Soft
Start
Oscillator
GND
Figure 3. Block Diagram of FP6357
FP6357-Preliminary 0.1-MAY-2013
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fitipower integrated technology lnc.
Absolute Maximum Ratings
(Note 1)
FP6357
/a85T
● VIN to GND ------------------------------------------------------------------------------------------------------ -0.3V to +6.5V
● LX to GND ------------------------------------------------------------------------------------------------------- -0.3V to (V
IN
+0.3)
● Dynamic LX voltage in 50ns duration ------------------------------------------------------------------
-4V to (V
IN
+3V)
● EN, FB, PG to GND ------------------------------------------------------------------------------------------- -0.3V to V
IN
● Package Thermal Resistance (θ
JA
)
SOT-23-5 --------------------------------------------------------------------------------------------- 250ºC/W
SOT-23-6 --------------------------------------------------------------------------------------------- 250ºC/W
● Package hermal
esistance (θ
JC
)
SOT-23-5 --------------------------------------------------------------------------------------------- 130°C/W
SOT-23-6 --------------------------------------------------------------------------------------------- 110°C/W
● Maximum Junction Temperature (T
J
) --------------------------------------------------------------------- +150°C
● Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------- +260°C
● Storage Temperature (T
STG
) --------------------------------------------------------------------------------- -65°C to +150℃
Note 1：Stresses beyond those listed under “Absolute Maximum
atings" may cause permanent damage to the device
Recommended Operating Conditions
(Note 2)
● Supply Voltage V
IN
--------------------------------------------------------------------------------------------- +2.5V to +5.5V
● Junction Temperature Range ----------------------------------------------------------------------------
● Ambient Temperature Range -----------------------------------------------------------------------------
Note 2：The device is not guaranteed to function outside its operating conditions.
-40°C to +125°C
-40°C to +85°C
FP6357-Preliminary 0.1-MAY-2013
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fitipower integrated technology lnc.
Electrical Characteristics
(V
IN
=5V, T
A
=25
°C
, unless otherwise specified.)
Parameter
Input Voltage Range
Shutdown Current
Quiescent Current
Reference Voltage
FB Input Leakage Current
P-Channel MOSFET On-Resistance
(Note 3)
N-Channel MOSFET On-Resistance
(Note 3)
P-Channel Current Limit (Note 3)
EN High-Level Input Voltage
EN Low-Level Input Voltage
Under Voltage Lockout Voltage
UVLO Hysteresis
Oscillation Frequency
Minimum On Time
Maximum Duty Cycle
PG Rising Threshold (SOT-23-6)
PG Sink Current (SOT-23-6)
V
OUT
Discharge Resistance
Thermal Shutdown Temperature (Note 3)
Internal Soft-Start Time
Note 3：Guarantee by design.
FP6357
/a85T
Min
2.5
Typ
Max
5.5
0.1
80
0.588
0.6
0.01
200
150
1.5
1.5
0.4
2.4
0.2
1.2
1.5
50
100
1.8
0.612
1
1
Unit
V
μA
μA
V
µA
mΩ
mΩ
A
V
V
V
V
MHz
ns
%
90
1
100
%
mA
Ω
°C
ms
Symbol
V
IN
I
SHDN
I
q
V
REF
I
FB
R
DS(ON)
R
DS(ON)
I
LIM
V
IH
V
IL
UVLO
V
HYS
F
OSC
Conditions
EN=GND
V
FB
=0.65V, I
O
=0A
V
FB
=V
IN
V
PG (H)
I
PG
V
FB
Rising
V
PG
=0.1V
T
SD
T
SS
150
1
FP6357-Preliminary 0.1-MAY-2013
5
嵌入式系统
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