Protection IC Datasheet
© 2022 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: FW.12/01/22
LS12052BD33
18V, 5A eFuse with Over-Voltage Protection and Blocking FET Control
Features and Benefits
RoHS
Pb
Description
The LS12052BD33 family of integrated load switches provides an
easy circuit protection to power the system. The device uses few
external components and provides multiple protection modes.
They are a robust defense against overload, short circuit, input
voltage surge, excessive inrush current and reverse current
blocking with an external NFET. The switch’s low R
DS(ON)
helps to
reduce power loss during normal operation. Current limit level can
be set with a single external resistor. Input over voltage events are
protected by internal clamp circuitry to a safe output voltage.
Programmable soft-start controls the slew rate of the output
voltage to limit inrush current during plug in. It integrates thermal
fold-back function and over temperature shutdown protection. The
BFET pin is provided to drive an external NFET which can be
connected “Back to Back��� with the LS12052BD33 output. The
external NFET gate is driven by BFET to prevent current flow from
the load to the source. LS12052BD33 is available in small DFN
3mm x 3mm-10 package.
■ Wide Input Voltage Range
from 2.7V to 18V
■ Extremely Low R
DS(ON)
for the
Integrated Protection Switch:
25mΩ
■ External Programmable Soft-
Start Time
■ External Programmable
Current Limit
■ Support Reverse Current
Blocking
■ Short-circuit Protection
■ Fixed Over-voltage 14.4V
Output Voltage Clamp
■ Accurate 1.29V EN Pin Turn-
on Threshold
■ Thermal Shutdown
Protection& Auto Recovery
■ DFN3×3_10L Packages
■ Pb-Free and RoHS Compliant
Applications
■ HDD and SSD Drives
■ Adapter Powered Devices
■ Notebook PC
■ PCI, PCIe Cards
■ Industry
Pinout Designation
1
3
2
OUT
IN
5
OUT
6
7
8
SS
IN
GND
4
OUT
9
10
EN
IN
ILIM
BFET
EXPOSED PAD ON BACKSIDE
5
Pin # Pin Name
Description
3,4,5 IN Power input pin.
9 BFET
External NFET gate driver. Control an
external NFET which can be connected
“Back to Back” with the LS12052BD33
output to prevent current flowing from the
load to the source. Float this pin if it is not
used.
10 ILIM
Current limit program pin. Program the
current limit by connecting a resister to
ground.
1 SS
Soft Start time program pin. Connect a
capacitor to ground to program the soft start
time.
2 EN
Enable interface pin. EN has accurate
ON/OFF threshold of 1.29V and 1.19V
respectively. Pull it above ON threshold to
enable the IC. Pull it below OFF threshold to
disable the IC.
6,7, 8 OUT Power output pin.
EP GND Ground pin.
Pin Description
IN
IN
EN
BFET
OUT
OUT
ILIM
SS
GND
VIN
10µF
C
IN1
12052BD33
VOUT(3A)
10µF
C
O1
R
LIM
3k
C
SS
10nF
IN OUT
(Current Limit=3.5A)
25mΩ
6
7
8
9
10
1
2
3
4
5
(2.4mS)
C
IN2
0.1µF
0.1µF
C
O2
NFET
C
EN
0.1µF
R
EN
10K
Typical Applications
Protection IC Datasheet
© 2022 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: FW.12/01/22
LS12052BD33
18V, 5A eFuse with Over-Voltage Protection and Blocking FET Control
Absolute Maximum Rating (Reference to GND)
* Notes:Stress exceeding those listed “Absolute Maximum Ratings” may damage the device.
Symbol Value Units
V
IN
-0.3 to +20 V
BFET -0.3 to V
IN
+6 V
EN -0.3 to +20 V
The other Pins -0.3 to +6.5 V
Junction Temperature Range -40 to +150 °C
Storage Temperature Range -65 to +150 °C
ESD, Human Body Model (HBM) ±2000 V
Lead Temperature (Soldering 10s) 260 °C
Recommend Operating Conditions
Symbol Value Units
Input Voltage (V
IN
) +2.7 to +18 V
Junction Temperature Range +125 °C
* Notes: The device is not guaranteed to function outside of the recommended operating conditions.
Symbol Value Units
Maximum Power Dissipation (T
A
=25°C ) 2.6 W
Thermal Resistance (θ
JA
)
38 °C/W
Thermal Resistance (θ
JC
)
8 °C/W
Note1: Measured on JESD51-7, 4-Layer PCB.
Note 2: The maximum allowable power dissipation is a function of the maximum junction temperature T
J_MAX
,
the junction to ambient thermal resistance θ
JA
, and the ambient temperature TA. The maximum allowable
continuous power dissipation at any ambient temperature is calculated by P
D_MAX
= (T
J_MAX
-T
A
)/θ
JA
. Exceeding
the maximum allowable power dissipation will cause excessive die temperature, and the regulator will go into
thermal shutdown. Internal thermal shutdown circuitry protects the device from permanent damage.
Thermal information
Soft-start
UVLO
Charge
Pump
IN
SS
EN
GND
or
Thermal
Detect
Limit
Current
V
OUT
Clamping
Driver
OUT
ILIM
BFET
2µA
SWEN
VCP
Discharge
control
R=120 Ω
170Ω
Functional Block Diagram