LP5308
36V Over-Voltage Protection Switch with
Programmable Over-Current Protection
Features
General Description
⚫
Input voltage tolerance up to 36V
⚫
Low on-state resistance to 135mΩ
⚫
90μA low current consumption
⚫
Adjustable OCP: 0.2A to 2.5A
⚫
Under-voltage lockout: 2.7V
⚫
Over-voltage protection: 5.85V
⚫
Output discharge integrated
⚫
Thermal shutdown protection
⚫
ESD Protection:
-
⚫
Human Body Model: 4kV
Charged Device Model: 0.5kV
Package: SOT23-6 and DFN-8
The LP5308 is a power switch device provides full
protection to systems and loads which may encounter
large current and input over-voltage conditions.
The device contains a 135mΩ MOSFET which can
operate over an input voltage range from 3.0V to 36V. The
OVP will disconnect VIN and VOUT when the voltage on
VIN is higher than over voltage threshold. The over-current
protection could be settable using an external resistor.
When the current reaches the threshold, the device will
turn off the power FET to prohibit excessive currents from
causing damage. Switch is controlled by an active-low
logic pin. Thermal shutdown protection is integrated which
shuts off the switch to prevent damage to the part when
the temperature is higher than threshold.
These parts are available in space-saving SOT23-6
package and DFN-8 package.
Applications
⚫
Notebook and PC
⚫
Cell phone and PDAs
⚫
USB or other peripheral ports
⚫
Camera
SOT23-6
Marking Information
LP5308
Ordering and Package Information
Part Number
LP5308QVF
F: Pb-Free
Package Type:
B6 : SOT23-6
QV : DFN-8
DFN-8
LP5308B6F
Top Mark
LPS
LP5308
YWX
LP5308
YWX
Package
Tape & Reel
DFN-8
4K/REEL
SOT23-6
3K/REEL
Marking indication:
Y: Production Year, W: Production week, X: Series Number
LP5308 Rev0.7 Jan-2022
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LP5308
Typical Application Circuitry
Figure 1. Typical Application Circuitry
Pin Configuration
SOT23-6 (Top View)
for LP5308B6F
DFN-8 (Top View)
for LP5308QVF
Pin Description
Pin
Description
GND
Ground
VIN
Power supply and input of power switch
VOUT
Output of power switch
ISET
Over-current protection setting pin, connect a resistor to ground
ENB
Active-low device enable pin
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LP5308
Functional Block Diagram
Figure 2. Internal Block Diagram (LP5308)
Absolute Maximum Ratings (Note 1)
⚫
VIN to GND ----------------------------------------------------------------------------------------------------------------- -0.3V to 36V
⚫
VOUT to GND ---------------------------------------------------------------------------------------------------------------- -0.3V to 7V
⚫
ENB to GND ------------------------------------------------------------------------------------------------------------------ -0.3V to 7V
⚫
ISET to GND ----------------------------------------------------------------------------------------------------------------- -0.3V to 7V
⚫
Maximum Junction Temperature (TA) ----------------------------------------------------------------------------------------- 150°C
⚫
Maximum Soldering Temperature (at leads, 10 seconds) ---------------------------------------------------------------- 260°C
Note 1: Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings
only, instead of functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the
specifications. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
Thermal Information
⚫
Maximum Power Dissipation (SOT23-6, PD, TA VOVP_R
to OUT voltage stop rising
30
ISHORT
VIN = 5V, TA=25°C
5
A
Output auto discharge
RDIS
VIN = 5V, VEN = 0V
3
kΩ
Enable logic high voltage level
VIH
VIN = 2.4V to 6V
Enable logic high voltage level
VIL
VIN = 2.4V to 6V
Over current protection level
OCP accuracy
Over-Voltage Protection
response time
Short circuit protection level
OCP qualification time
Load switch turned on delay
Output rising time
IOCP
A
ACCOCP
tOVP
tOCP_QUAL
tDON
tR
%
VIN = 5V, TA = 25°C, qualification time
from IOUT hits IOCP to switch turned off
50
1.4
ns
V
0.4
V
150
μs
VIN = 5V, ROUT = 100Ω, COUT = 22μF,
time from enabled to VOUT = 0.5
VIN = 5V, ROUT = 100Ω, COUT = 22μF,
time from VOUT = 0.1×VIN to 0.9×VIN
VIN = 5V, ROUT = 500Ω, COUT = 0.1μF,
time from disabled to VOUT = 0.9×VIN
10
ms
450
μs
10
μs
Load switch turned off delay
tOFF
Thermal shutdown trigger
TSD
Temperature rising
150
°C
Thermal shutdown release
TSD_REL
Temperature falling
130
°C
Note 3. The parameter is guaranteed by design and characterization.
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LP5308
Typical Timing Diagram
Figure 3. Start-up and over current protection
Typical Performance Characteristics
Figure 4. Quiescent Current vs Temperature and VIN
(CIN=COUT=1μF, VENB = 0V, no load)
Figure 5. Shutdown Current vs VIN and Temperature
(CIN=COUT=1μF, VENB = 5V, no load)
Figure 6. On-resistance vs Temperature
(VENB = 0V, ILOAD = 100mA)
Figure 7. On-resistance vs Input Voltage
(VENB = 0V, ILOAD = 100mA)
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LP5308
Typical Operating Waveforms
Figure 8. Start-up with enabled by ENB
(VIN = 5V, CIN = COUT = 1μF, RLOAD = 10Ω)
Figure 9. Disabled by ENB
(VIN = 5V, CIN = COUT = 1μF, RLOAD = 10Ω)
Figure 10. Over-Current Protection Response
(ISET floating, VENB = 0V, 160µs debounce included)
Figure 11. Short-Circuit Protection Response
(ISET floating, VENB = 0V)
Figure 12. Over-Voltage Protection Response
(VIN normal ramp-up with 4V / 100ns, RLOAD = 100Ω)
Figure 13. Over-Voltage Protection Response
(VIN fast ramp-up with 25V / 100ns, RLOAD = 100Ω)
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LP5308
Function Description
General Description
Over-Current Protection
LP5308 is a OVP power switch integrated OCP feature to
protect systems and loads which can be damaged or
disrupted by the application of high currents. The devices
all contain a 135mΩ N-channel MOSFET and a controller
capable of working over a wide input operating range of
3V to 36V. The controller protects against system
malfunctions through over-current protection, undervoltage lockout and thermal shutdown. The OCP is
adjustable from 0.2A to 2.5A through an external resistor.
The OCP feature ensures that the device will disconnect
output from input when current through the switch exceed
a setting value. The current at which the parts will limit is
adjustable through the selection of an external resistor
connected to ISET. Once the switch is turned off, unless
by disabled through ENB pin, it will not conduct again until
1.3s later. The hiccup behavior will continue as long as the
heavy loading condition exist.
Over-Voltage Protection
Enable Control
The ENB pin controls the state of the switch. When ENB
is pulled low or floating more than 10ms de-bounce time,
the load switch is turned on. Activating ENB continuously
holds the switch in the on state so long as there is no fault.
An under-voltage, over-voltage condition on VIN or a
junction temperature in excess of 150°C overrides the
ENB control to turn off the switch. The LP5308 does not
turn off in response to an over current condition until the
current exceed threshold longer than qualification time
150µs, as long as ENB is active and the thermal shutdown
or VIN voltage not in proper range.
The enable pin ENB’s control voltage and VIN pin have
independent recommended operating ranges. The ENB
pin voltage can be driven by a voltage level higher than the
input voltage. There is internal pull-down resistor on ENB
pin. Leave the pin floating will active the device as well.
The LP5308 has Over-Voltage protection to prevent high
voltage on VIN passing through to VOUT. Once the
voltage on input exceeds the OVP threshold, the power
FET will be turned off immediately. When VIN drop back
below OVP release level, the switch will be turned on again
after a 10ms de-bounce time.
Under-Voltage Lockout
The under-voltage lockout turns-off the switch if the input
voltage drops below the under-voltage lockout threshold.
With the ENB pin active, the input voltage rising above the
under-voltage lockout threshold more than 10ms will
cause a controlled turn-on of the switch which limits
current over-shoots.
Thermal Shutdown
The thermal shutdown protects the device from internally
or externally generated excessive temperatures. During
an over temperature condition, the switch is turned off. The
switch automatically turns on again if the temperature
drops below the threshold temperature more than 1.3s.
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LP5308
Application Information
The LP5308 OCP is set with an external resistor connected between ISET pin and GND. This resistor is selected using
the following equation:
25𝐾
𝑅SET =
(1)
I
OCP
Where, RSET, united as kΩ, is the resistor connected to ISET. IOCP is the expected current limit value in mA. Resistor
tolerance of 1% or less is recommended.
The relationship between RSET and IOCP could also be found as below diagram:
2.2
IOCP [A]
1.7
1.2
0.7
0.2
10
20
30
40
50
60
70
80
90
100
RSET [KΩ]
Figure 4. OCP trigger level vs resistor on ISET pin
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LP5308
Package Information
SOT23-6
A
D
B
C
A1
b
1.00
2.60
e
H
0.95
L
0.5
Recommended Land Pattern
SYMBOL
A
A1
B
b
C
D
e
H
L
MIN
0.889
0.000
1.397
0.28
2.591
2.692
0.080
0.300
MILLIMETER
NOM
1.100
0.050
1.600
0.35
2.800
2.920
0.95BSC
0.152
0.450
MAX
1.295
0.152
1.803
0.559
3.000
3.120
0.254
0.610
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LP5308
DFN-8
D1
L
E
E1
F
D
b
e
BOTTOM VIEW
TOP VIEW
2.50
0.75
0.6
A1
C
A
1.65
0.25
Recommended Land Pattern
SIDE VIEW
SYMBOL
A
A1
b
c
D
D1
E
E1
e
L
F
0.50
MIN
0.70
0.00
0.18
1.90
1.10
1.90
0.60
0.25
0.25
Dimensions In Millimeters
NOM
0.75
0.02
0.25
0.20 REF
2.00
1.30
2.00
0.75
0.50 BSC
0.35
0.30
MAX
0.80
0.05
0.30
2.10
1.65
2.10
0.85
0.40
0.35
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