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fitipower integrated technology lnc.
FP6381A
High Efficiency 1.5MHz/a18.52AT
Synchronous Step Down Regulator
Description
The FP6381A 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.
Pin Assignments
S5 Package (SOT-23-5)
FB
VIN
54 1 23
EN GND LX
S6 Package (SOT-23-6)
FB PG VIN
6 54 1 23
EN GND LX
S8 Package (TSOT-23-5)
FB VIN
54 1 23
Features
Low RDS(ON) for Internal Switch (Top/Bottom): 300/250mΩ
2.5V~5.5V Input Voltage Range 1.2A Output Current 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 Tablet Portable Equipment
Ordering Information
FP6381A□□□
TR: Tape/Reel
C: Green
Package Type S5: SOT-23-5 S6: SOT-23-6 S8: TSOT-23-5
SOT-23-5 Marking
Part Number FP6381AS5CTR
Product Code FA2
SOT-23-6 Marking
Part Number FP6381AS6CTR
Product Code FC4
TSOT-23-5 Marking
Part Number
Product Code
FP6381AS8CTR
FF5
EN GND LX
Figure 1. Pin Assignment of FP6381A
FP6381A-0.3-DEC-2013
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Typical Application Circuit
VIN C1 C4
PG
OFF ON EN
VIN LX
FP6381A
R3
PG GND
FB
L1
R1
C3
(opt.)
R2
FP6381A /a85T
VOUT C2
Figure 2. Schematic Diagram
VIN=5V, the recommended BOM list is as below.
VOUT 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
C4 0.1μF MLCC 0.1μF MLCC 0.1μF MLCC 0.1μF MLCC 0.1μF MLCC 0.1μF MLCC
R1 453kΩ 316kΩ 200kΩ 150kΩ 100kΩ 75kΩ
R2 100kΩ 100kΩ 100kΩ 100kΩ 100kΩ 100kΩ
Table 1. Recommended Component Values
L1 2.2μH 2.2μH 2.2μH 1.8μH 1.8μH 1.5μH
C2 10μF MLCC 10μF MLCC 10μF MLCC 10μF MLCC 10μF MLCC 10μF MLCC
FP6381A-0.3-DEC-2013
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FP6381A
Functional Pin Description
/a85T
Pin Name VIN
Pin No. (SOT-23-5) (TSOT-23-5)
4
Pin No. (SOT-23-6)
4
Pin Function Power Supply Input Pin. Drive VIN pin by 2.5V to 5.5V voltage to power on the chip.
GND EN FB PG LX
2 1 5 -3
2 Ground Pin.
1
Enable Control. Pull high to turn the IC on, and pull low to disable the IC. Don’t leave this pin floating.
6
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.
5 Open Drain Power Good Output Pin.
3
Power Switching Output. Connect an inductor to the drains of internal high side PMOS and low side NMOS.
Block Diagram
PG (SOT-23-6)
EN
VIN
Power Good
1M
Enable Control
Undervoltage Lockout
Bias Supply
90% VREF
FB
EA
Compensation
VREF
Soft Start
Slope Compensation
COMP
Control Logic Current Limit
Logic
Control and
Driver Logic
1X
Oscillator
COMP
LX GND
Figure 3. Block Diagram of FP6381A
FP6381A-0.3-DEC-2013
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FP6381A
Absolute Maximum Ratings (Note 1)
/a85T
● VIN to GND ------------------------------------------------------------------------------------------------------ -0.3V to +6.5V
● LX to GND ------------------------------------------------------------------------------------------------------- -0.3V to VIN+0.3V ● EN, FB, PG to GND ------------------------------------------------------------------------------------------- -0.3V to VIN ● Package Thermal Resistance, (θJA)
SOT-23-5 ------------------------------------------------------------------------------------------ +250ºC/W
TSOT-23-5 ------------------------------------------------------------------------------------------ +250ºC/W
SOT-23-6 -----------------------------------------------------------------------------------------● Package Thermal Resistance, (θJC)
SOT-23-5 ------------------------------------------------------------------------------------------
+250ºC/W +130°C/W
TSOT-23-5 ------------------------------------------------------------------------------------------ +130°C/W
SOT-23-6 ------------------------------------------------------------------------------------------ +110ºC/W ● Maximum Junction Temperature (TJ) ---------------------------------------------------------------------- +150°C ● Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------- +260°C ● Storage Temperature (TSTG) --------------------------------------------------------------------------------- -65°C to +150℃
Note 1:Stresses beyond those listed under “Absolute Maximum Ratings" may cause permanent damage to th.