DC1575B - Demo Manual

DEMO MANUAL DC1575B
LTC4362-2:
Monolithic Overvoltage/
Overcurrent Protector
DESCRIPTION
Demonstration circuit 1575B features the LTC®4362, a
monolithic overvoltage/overcurrent protector that safeguards 2.5V to 5.5V systems from power supply overvoltage. It is designed for portable devices with multiple
power supply options including wall adaptors, car battery
adaptors and USB ports.
The LTC4362 controls an internal 40mΩ N-channel MOSFET
in series with the input power supply. During overvoltage
transients, the LTC4362 turns off the MOSFET within 1μs,
isolating downstream components from the input supply.
In most applications, the LTC4362 rides through inductive cable transients without requiring transient voltage
suppressors or other external components. An internal
current sense resistor is used to implement overcurrent
protection.
The LTC4362 has a delayed start-up at plug-in and controlled dV/dt ramp-up for inrush current limiting. A PWRGD
pin provides power good monitoring for VIN. The LTC4362
PERFORMANCE SUMMARY
features a soft-shutdown controlled by the ON pin and
drives an optional external P-channel MOSFET for negative
voltage protection. Following an overvoltage condition,
the LTC4362 automatically restarts with a 130ms delay.
After an overcurrent fault, the LTC4362-1 remains off while
the LTC4362-2 (featured on the DC1575B) automatically
restarts after a 130ms delay.
DC1575B demonstrates two protection schemes selected
with a jumper. The first selection is overvoltage and
overcurrent protection. The second selection is overvoltage, overcurrent, and negative voltage protection. Also
on the DC1575B is ON control with another jumper, input
LEDs indicating positive or negative input voltage, output
LED and connection for USB protected output.
Design files for this circuit board are available at
http://www.linear.com/demo/DC1575B
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
(TA = 25°C)
PARAMETER
CONDITION
VALUE
Input Voltage
JP2: OV/OC
JP2: OV/OC/NV
0V to 28V
–30V to 28V
Output Voltage
Input Range for Gate Turn-On
2.1V to 5.8V
Overcurrent Threshold
Internal Sense Resistor
1.5A
Overcurrent Retry
LTC4362-2
Auto-Retry
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DEMO MANUAL DC1575B
QUICK START PROCEDURE
Demonstration circuit 1575B is easy to set up to evaluate
the performance of the LTC4362. Refer to Figures 1 and 2
for proper measurement equipment setup and follow the
procedure below:
1)Connect the load and measurement across the OUT
and GND (Figure 1).
2)Select protection type at JP2:
a)For overvoltage and overcurrent protection select
OV/OC.
b)For overvoltage, overcurrent and negative voltage
protection select OV/OC/NV.
3)Select ENABLE at JP1 to enable the protection.
4)Connect a power supply across VIN and GND.
5)For USB protection, connect a USB cable from J2 to
the USB device (Figure 2). Select the protection type
at JP2. Connect a second USB cable from a computer
to J1.
SELECT PROTECTION
PROTECTED
OUT
VIN
+
–
LOAD
PWRGD
SELECT ENABLE
Figure 1. DC1575B Basic Setup
PC
USB
CABLE
(HOT PLUG)
USB
CABLE
USB
DEVICE
SELECT PROTECTION
SELECT ENABLE
Figure 2. DC1575B USB Protection Setup
2
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DEMO MANUAL DC1575B
OPERATION
The DC1575B is used to evaluate the LTC®4362 in two
protection configurations selected at JP2 for overvoltage
and overcurrent protection, or overvoltage, overcurrent,
and negative voltage protection. The device in need of
protection is connected to the OUT test point or to the
USB output connector J2. An input supply is connected
at VIN or a USB source is connected at J1.
ON Control
The ON pin on the LTC4362 is controlled at JP1. Select
ENABLE to enable the LTC4362, or DISABLE to enter a
low current sleep mode.
Protection OV/OC
The first selection at JP2 is OV/OC protection which protects against overvoltage and overcurrent. The LTC4362
turns on an internal N-channel MOSFET when the input
voltage is below the overvoltage threshold. An internal
current sense resistor provides overcurrent detection.
In the case of an overcurrent, the LTC4362-2 used in the
DC1575B automatically tries to turn the internal MOSFET
back on. An orange input LED indicates if the input supply
is on while a green OUT LED indicates the gate is on and
input is connected to the output.
Protection OV/OC/NV
The second selection at JP2 is OV/OC/NV protection which
protects against overvoltage, overcurrent and negative
voltage. The LTC4362 turns on an internal N-channel
MOSFET when the input voltage is below the overvoltage
threshold. A P-channel MOSFET is driven by the GATEP pin
of the LTC4362 to protect the output against an inadvertent
negative voltage connection at the input. An internal current
sense resistor provides overcurrent detection. In the case
of an overcurrent, the LTC4362-2 used in the DC1575B
automatically retries to turn the internal MOSFET back
on. The orange VIN LED indicates if the input supply is on
while a green OUT LED indicates the gate is on and input
is passed over to the output. A red –VIN LED indicates if
a negative input voltage is present.
USB Protection
DC1575B also provides connection for USB protection.
First connect a USB device with a USB cable at J2. Select
the protection type at JP2 and match this with JP3. Select
ENABLE at JP1. The USB source can then be connected
at J1.
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DEMO MANUAL DC1575B
PARTS LIST
ITEM
QUANTITY
REFERENCE
DESCRIPTION
MANUFACTURER’S PART NUMBER
1
2
CLD1, CLD2
Current Limiting Diode, 3.2V SOD-80
Central Semiconductor Corporation CMJ3500 TR
2
1
C1
Capacitor, X5R 10µF 10V 20% 0603
Samsung CL10A106MP8NNNC
3
1
D1
LED, Green
ROHM SML-010FTT86L
4
1
D2
LED, Orange
ROHM SML-010DTT86M
5
1
D3
LED, Red
ROHM SML-010VTT86L
6
1
D5
Zener Diode, 5.6V SOD-523
Diodes Inc. BZT52C5V6T-7
7
6
E1, E2, E3, E4, E5, E6
Turret, Testpoint 0.094"
Mill Max 2501-2-00-80-00-00-07-0
8
2
JP1, JP2
Headers, Single Row 3 Pins 2mm Ctrs.
Samtec TMM-103-02-L-S
9
1
J1
USB Connection, Type B USB
Mill-Max 897-43-004-90-000000
10
1
J2
USB Connection, Type A USB
Mill-Max 896-43-004-90-000000
11
1
Q1
MOSFET P-Channel, 30V SOT-363
Vishay Si1471DH-T1-E3
12
1
R1
Res., Chip 1k 1/10W 5% 0603
NIC Components Corporation NRC06J102TRF
13
1
R2
Res., Chip 1.5k 0.06W 5% 0603
Vishay CRCW06031K50JNEA
14
1
U1
I.C., Overvoltage/Overcurrent Protector
DFN(08)(DCB) 2mm × 3mm
Linear Technology Corporation LTC4362CDCB-2
15
2
XJP1, XJP2
Shunt, 2mm Ctrs.
Samtec 2SN-BK-G
Note: DC1575B replaces DC1575A due to obsoleted LEDs used in DC1575A.
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Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation
that the interconnection of its circuits as described herein will not infringe on existing patent rights.
A
B
C
D
GND
D+
D-
VCC



5


GND
D+
D-
VCC






4
ON
GATEP
SENSE
IN
CUSTOMER NOTICE




B
EXPOSED PAD
GND

Replaced CLD1,CLD2,D1-D3

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


APPROVALS
DILIAN R.
SCALE = NONE
2
DATE
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
 www.linear.com

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IC NO.
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MODIFY DATE: 
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SIZE
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TECHNOLOGY
TITLE: SCHEMATIC

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THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
3




2
REVISION HISTORY
DESCRIPTION
APPROVED


OUT
OUT
PWRGD



ECO REV

3
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO
PCB DES.
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APP ENG.
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.


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
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

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
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
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
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5
A
B
C
D
DEMO MANUAL DC1575B
SCHEMATIC DIAGRAM
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DEMO MANUAL DC1575B
DEMONSTRATION BOARD IMPORTANT NOTICE
Linear Technology Corporation (LTC) provides the enclosed product(s) under the following AS IS conditions:
This demonstration board (DEMO BOARD) kit being sold or provided by Linear Technology is intended for use for ENGINEERING DEVELOPMENT
OR EVALUATION PURPOSES ONLY and is not provided by LTC for commercial use. As such, the DEMO BOARD herein may not be complete
in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including but not limited to product safety
measures typically found in finished commercial goods. As a prototype, this product does not fall within the scope of the European Union directive on electromagnetic compatibility and therefore may or may not meet the technical requirements of the directive, or other regulations.
If this evaluation kit does not meet the specifications recited in the DEMO BOARD manual the kit may be returned within 30 days from the date
of delivery for a full refund. THE FOREGOING WARRANTY IS THE EXCLUSIVE WARRANTY MADE BY THE SELLER TO BUYER AND IS IN LIEU
OF ALL OTHER WARRANTIES, EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS
FOR ANY PARTICULAR PURPOSE. EXCEPT TO THE EXTENT OF THIS INDEMNITY, NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR
ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES.
The user assumes all responsibility and liability for proper and safe handling of the goods. Further, the user releases LTC from all claims
arising from the handling or use of the goods. Due to the open construction of the product, it is the user’s responsibility to take any and all
appropriate precautions with regard to electrostatic discharge. Also be aware that the products herein may not be regulatory compliant or
agency certified (FCC, UL, CE, etc.).
No License is granted under any patent right or other intellectual property whatsoever. LTC assumes no liability for applications assistance,
customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind.
LTC currently services a variety of customers for products around the world, and therefore this transaction is not exclusive.
Please read the DEMO BOARD manual prior to handling the product. Persons handling this product must have electronics training and
observe good laboratory practice standards. Common sense is encouraged.
This notice contains important safety information about temperatures and voltages. For further safety concerns, please contact a LTC application engineer.
Mailing Address:
Linear Technology
1630 McCarthy Blvd.
Milpitas, CA 95035
Copyright © 2004, Linear Technology Corporation
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Linear Technology Corporation
LT 0914 REV A • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
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