Microsemi LX8204 12 V E-Fuse User manual

User Guide
LX8204 12 V E-Fuse Evaluation Board

LX8204 12 V E-Fuse Evaluation Board
Microsemi Proprietary and Confidential. User Guide Revision 1.0
Contents
1 Revision History ............................................................................................................................ 1
1.1 Revision 1.0 ........................................................................................................................................ 1
2 Product Description ....................................................................................................................... 2
2.1 Applications ........................................................................................................................................ 2
2.2 Key Features ....................................................................................................................................... 2
3 Evaluation Board Schematic .......................................................................................................... 3
4 Recommended Operating Conditions ............................................................................................ 4
5 PCB Layout of Evaluation Board ..................................................................................................... 5
6 Bill of Materials .............................................................................................................................. 7
7 Test Procedure ............................................................................................................................... 8
8 Ordering Information ..................................................................................................................... 9

LX8204 12 V E-Fuse Evaluation Board
Microsemi Proprietary and Confidential. User Guide Revision 1.0 1
1 Revision History
The revision history describes the changes that were implemented in the document. The changes are
listed by revision, starting with the most current publication.
1.1 Revision 1.0
Revision 1.0 was published in August 2017. It was the first publication of this document.

LX8204 12 V E-Fuse Evaluation Board
Microsemi Proprietary and Confidential. User Guide Revision 1.0 2
2 Product Description
The LX8204 is a fast-acting E-Fuse switch designed to protect circuitry connected to its output (VOUT)
from transient input voltage surges on its input (VCC), and to protect VCC from overload current events
coming from the load on VOUT.
Voltage protection features include under-voltage lockout (UVLO), and over-voltage clamping. This
clamp limits VOUT voltage allowing continued circuit operation during an input over-voltage transient
condition, while UVLO ensures that VOUT remains off until VCC reaches its minimum operating
threshold. On the current side, the LX8204 protects the input from output short circuit and/or over-
current condition with a 2 A–3.5 A current limit circuit. Additionally, the LX8204 protects the subsequent
systems from hot-swap condition.
Another protection feature is latching thermal shutdown of VOUT, with a fault flag output on the
combined EN/FAULT pin. Once thermal shutdown threshold is reached and the E-Fuse switch opens, the
tri-state EN/FAULT pin will be pulled to about 1.6 V, signaling to the system and potentially other
connected E-Fuse switches that a fault has occurred.
2.1 Applications
Hard-disk drive
Solid-state drive
Hot swap
PC cards
2.2 Key Features
Protected from hot-swap condition
50 mΩ(typical) RDSON internal E-Fuse FET protected from 24 V
Up to 24 V transient input range
<15 V output voltage clamp including dynamic transient
Continuous operation during VCC surge
2 A–3.5 A current limit at overloading
Over-temperature protection
13 ms and 1.4 ms/3.5 ms soft start rise time
Current limit during output soft start
UVLO detection
3 mm × 3 mm DFN available

LX8204 12 V E-Fuse Evaluation Board
Microsemi Proprietary and Confidential. User Guide Revision 1.0 3
3 Evaluation Board Schematic
The following illustration shows the evaluation board schematic.
Figure 1 • Evaluation Board Schematic

LX8204 12 V E-Fuse Evaluation Board
Microsemi Proprietary and Confidential. User Guide Revision 1.0 4
4 Recommended Operating Conditions
The following table lists the recommended operating conditions for the LX8204 evaluation board.
Table 1 • Recommended Operating Conditions
Description Symbol Min Max Unit
Input voltage VIN 10.8 18 V
Output current IOUT 0 3.5 A
Junction temperature TA–40 125 °C

LX8204 12 V E-Fuse Evaluation Board
Microsemi Proprietary and Confidential. User Guide Revision 1.0 5
5 PCB Layout of Evaluation Board
The LX8204 evaluation board is a four-layer board. The following illustrations depict each of the board's
four layers.
Figure 2 • Layer 1: Top Layer
Figure 3 • Layer 2: Ground Layer

LX8204 12 V E-Fuse Evaluation Board
Microsemi Proprietary and Confidential. User Guide Revision 1.0 6
Figure 4 • Layer 3: Third Layer
Figure 5 • Layer 4: Bottom Layer

LX8204 12 V E-Fuse Evaluation Board
Microsemi Proprietary and Confidential. User Guide Revision 1.0 7
6 Bill of Materials
The following table lists the bill of materials for the LX8204 evaluation board.
Table 2 • Bill of Materials
Item Part Type Part Description Reference Qty
1 Miscellaneous Components Microsemi IC—LX8204 U1 1
2 Miscellaneous Components Test point (J3) EN/FAULT 1
3 Miscellaneous Components Terminal VIN, VOUT, GND 3
4 Miscellaneous Components Jumper/2-pin J2 1
5 Miscellaneous Components 2N7002 Q5 1
6 Capacitors 1 µF/50 V/10%/0805/X5R C16 1
7 Capacitors 33 µF/25 V/10%/0805/X5R C8 1
8 Resistors 500 kΩ/1%/0805 R1 1
9 Resistors 100 kΩ/1%/0805 R9 1

LX8204 12 V E-Fuse Evaluation Board
Microsemi Proprietary and Confidential. User Guide Revision 1.0 8
1.
2.
3.
7 Test Procedure
The following lists the LX8204 evaluation board test point connections.
Table 3 • Test Point Connections
Name Description
VIN Device power input connector.
VOUT Device power output connector.
GND Ground pin for both input and output.
The following steps describe the test procedure.
Before connecting the power supply to the VIN and GND connector pins, set the power supply
voltage to 12 V.
Turn on the power supply. Use the oscilloscope to measure the soft start output voltage. The soft
start time should be 1.2 ms.
Start to increase the load current up to trigger thermal shutdown. Check the over-current level and
EN pin voltage. EN voltage should be around 1.7 V. Over current limit is around 3.5 A.