1
dc1555cfd
DEMO MANUAL DC1555C
Description
LTC4365/LTC4365-1:
Overvoltage, Undervoltage and
Reverse Supply Protection Controller
Demonstration circuit DC1555C is intended to demon-
strate the performance of the LTC4365 and LTC4365-1
Undervoltage, Overvoltage and Reverse Supply Protection
Controllers.
The LT C
®
4365/LTC4365-1 protect circuits from input volt-
ages that may be too high, too low or negative. It operates
by controlling the gates of two back-to-back connected
MOSFETs to keep the output in a safe range. The OV and
UV protection levels are adjusted by resistive dividers at
the OV and UV pins. Asserting the SHDN pin disables the
MOSFETs and places the controller in a low-current shut-
down state. The FAULT pin is asserted when the Controller
is in shutdown mode or when the input voltage is outside
of the UV or OV level.
The LTC4365 and LTC4365-1 can withstand DC voltages
between –40V and +60V and have a valid operating range
of 2.5V to 34V.
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.
performance summary
(TA = 25°C)
Regarding the supply protection parameters, the LTC4365
and LTC4365-1 are identical. The only differences are
in the gate fault recovery delay time and the delay from
turn-off to low-power operation. These delays are 36ms
(typ, both) for the LTC4365, while they are 1ms and 0.7ms
respectively for the LTC4365-1.
The DC1555C includes the controller, two back-to-back
connected power MOSFETs, three jumpers and three
LEDs to indicate the input and output voltages and the
FAULT pin signal.
Design files for this circuit board are available at
http://www.linear.com/demo/DC1555C
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VIN Board Input Voltage Range –30 30 V
VIN(UVLO) Input Supply Undervoltage Lockout VIN Rising 1.8 2.2 2.4 V
IVIN Input Supply Current SHDN = 0V
SHDN = 2.5V
10
25
50
150
µA
µA
IVIN(R) Reverse Input Supply Current VIN = –40V, VOUT = 0V –1.2 –1.8 mA
ΔVGATE External N-Channel Gate Drive (GATE – VOUT) VIN = VOUT = 5V, IGATE = –1µA
VIN = VOUT = 12V to 34V, IGATE = –1µA
3
7.4
3.6
8.4
4.2
9.8
V
V
IGATE(UP) External N-Channel Gate Pull-Up current GATE = VIN = VOUT = 12V –12 –20 –30 µA
IGATE(FAST) External N-Channel Fast Gate Pull-Down Current Fast Shutdown, GATE = 20V, VIN = VOUT = 12V 31 50 72 mA
IGATE(SLOW) External N-Channel Gentle Gate Pull-Down Current Gentle Shutdown, GATE = 20V, VIN = VOUT = 12V 50 90 150 µA
VUV UV Input Threshold Voltage UV Falling → ΔVGATE = 0V 492.5 500 507.5 mV
VOV OV Input Threshold Voltage OV Rising → ΔVGATE = 0V 492.5 500 507.5 mV
tGATE(FAST) External N-Channel Fast Gate Turn-Off Delay CGATE = 2.2nF, UV or OV Fault 2 4 µs
tFAULT OV, UV Fault Propagation Delay Overdrive = 50mV, VIN = VOUT = 12V 1 2 µs
VSHDN SHDN Input Threshold SHDN Falling to ΔVGATE = 0V 0.4 0.75 1.2 V
2
dc1555cfd
DEMO MANUAL DC1555C
operating principles
The LTC4365/LTC4365-1 monitors the input rail voltage
and disconnects downstream circuits when the input volt-
age is too low, too high or negative. The LTC4365 provides
accurate overvoltage and undervoltage comparators to
ensure that power is applied to the system only if the input
supply is within the allowable voltage window. Reverse
supply protection circuit automatically isolates the load
from negative input voltages.
During normal operation, a high voltage charge pump
enhances the gate of external N-channel power MOSFETs.
The controller consumes 10µA during shutdown and
125µA while operating.
3
dc1555cfd
DEMO MANUAL DC1555C
Demonstration circuit 1555C is easy to set up to evaluate
the performance of the LTC4365/LTC4365-1. Refer to
Figures 1a and 1b for proper measurement equipment
setup and follow the procedure below.
Note that the circuit on the DC1555C is optimized for 12V
operation. The Si4214 FET limits overvoltage and reverse
voltage to 30V and –30V, respectively. Refer to the LTC4365
data sheet for applications optimized for other voltages.
Reverse Voltage Test (Figure 1b)
1) Set JP1 to EN.
2) Set JP2 and JP3 to CONNECT LED.
3) Connect a power supply across VIN and GND in a
negative configuration (connect positive rail to GND
and negative rail to VIN).
4) Connect voltmeters at the input and output and am-
meter in series with supply.
5) Ramp VIN down to –30V (referenced to GND).
6) Verify that the output voltage is between 0V and –0.5V,
all LEDs are off, and the input current is <1.8mA. (FET
leakage or other board leakage paths can pull VOUT
slightly negative, but it will be clamped by the internal
protection diode.)
7) Ramp supply back to 0V.
Undervoltage/Overvoltage Test (Figure 1a)
8) Reverse the polarity of power supply connection across
VIN to GND (connect positive rail to VIN and negative
rail to GND).
9) Ramp supply up to 30V and verify green VIN LED, red
FAULT LED, green VOUT LED, and VOUT according to
Table 1 within the various voltage ranges.
10) Ramp supply down from 30V down to 0V and verify
green VIN LED, red FAULT LED, green VOUT LED, and
VOUT according to Table 1.
Table 1
VIN VOUT VIN LED VOUT LED FAULT LED
0V to 5.77V = 0V Off/Dim/On Off On
6.56V to 13.51V = VIN On On Off
15.47V to 30V = 0V On Off On
Jumper Test
11) Remove load and set supply to 9V.
12) Move jumpers and verify LEDs according to Table 2.
Table 2
JP1 JP2/JP3 VIN LED VOUT LED
EN CONNECT LED On On
DIS CONNECT LED On Off
EN Open Off Off
Quick start proceDure
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dc1555cfd
DEMO MANUAL DC1555C
Quick start proceDure
Figure 1a. Undervoltage/Overvoltage Measurement
Figure 1b. Reverse Voltage Measurement
5
dc1555cfd
DEMO MANUAL DC1555C
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 representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
schematic Diagram
5
5
4
4
3
3
2
2
1
1
DD
CC
B B
AA
LED DRIVE
VIN VOUT
-30 TO 0V
0V TO 6V
6V TO 15V
15V TO 30V
REVERSE PROTECTED
UV PROTECTED
GATE ON
OV PROTECTED
(UV = 6V)
(OV = 15V)
(LOW CURRENT MOSFET, SMALL PACKAGE OPTION)
*
*
*
BOARD ASSEMBLY
DC1555C-A
U1
LTC4365CTS8
DC1555C-B LTC4365CTS8-1
Apr 15, 2015
2Replaced Q1, LED's & CLD's. Vlad Ostrerov
VIN VOUT
REVISION HISTORY
DESCRIPTION DATE
APPROVED
ECO REV
Vlad Ostrerov
Replaced LED's, Added -B Assembly
- 1
Oct 26, 2015
REVISION HISTORY
DESCRIPTION DATE
APPROVED
ECO REV
Vlad Ostrerov
Replaced LED's, Added -B Assembly
- 1
Oct 26, 2015
REVISION HISTORY
DESCRIPTION DATE
APPROVED
ECO REV
Vlad Ostrerov
Replaced LED's, Added -B Assembly
- 1
Oct 26, 2015
SIZE
MODIFY DATE:
.VER.ON CI
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY
Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 McCarthy Blvd.
LTC CONFIDENTIAL - FOR CUSTOMER USE ONLY
CUSTOMER NOTICE
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
2
DEMO CIRCUIT 1555C
Oct 26, 2015
11
HIGH VOLTAGE NFET DRIVER UV, OV AND
N/A
LTC4365CTS8/LTC4365CTS8-1
RB
Vlad O.
REVERSE SUPPLY PROTECTION
SIZE
MODIFY DATE:
.VER.ON CI
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY
Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 McCarthy Blvd.
LTC CONFIDENTIAL - FOR CUSTOMER USE ONLY
CUSTOMER NOTICE
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
2
DEMO CIRCUIT 1555C
Oct 26, 2015
11
HIGH VOLTAGE NFET DRIVER UV, OV AND
N/A
LTC4365CTS8/LTC4365CTS8-1
RB
Vlad O.
REVERSE SUPPLY PROTECTION
SIZE
MODIFY DATE:
.VER.ON CI
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY
Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 McCarthy Blvd.
LTC CONFIDENTIAL - FOR CUSTOMER USE ONLY
CUSTOMER NOTICE
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
2
DEMO CIRCUIT 1555C
Oct 26, 2015
11
HIGH VOLTAGE NFET DRIVER UV, OV AND
N/A
LTC4365CTS8/LTC4365CTS8-1
RB
Vlad O.
REVERSE SUPPLY PROTECTION
C3
1000pF
(OPT)
0805
E8
FAULT
E1
VIN
D2
GRN
VOUT
E4
OV
R2
54.9k
1%
E5
SHDN
E3
UV
CLD2
CMJ2000 TR
D6
DFLT20A
(OPT)
D1
GRN
VIN
JP3
CONNECT
LED
OPEN
VOUT
1
3
2
R3
36.5k
1%
R1
1M
1%
D5
(OPT)
BZT52C15T
CLD3
CMJ2000 TR
E7
GND
C1
4.7µF
50V
(OPT)
Q2B
2N7002VC-7-F
(OPT)
G2
D2S2
R4
510k
D7
DFLT40A
(OPT)
JP2
VIN
1
3
2
+
C2
47µF
35V
(OPT)
JP1
EN
DIS
SHDN
1
3
2
D3
RED
FAULT
Q1B
Si4214DDY-T1-GE3
CLD1
CMJ2000 TR
U1
LTC4365CTS8
VIN
1
GATE
8
UV
2
VOUT
7
FAULT
6
OV
3
GND
4
SHDN
5
E6
VOUT
E2
GND
Q1A
Si4214DDY-T1-GE3
Q2A
2N7002VC-7-F
(OPT)
G1
D1 S1
D4
1N4148WT
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dc1555cfd
DEMO MANUAL DC1555C
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com
LINEAR TECHNOLOGY CORPORATION 2011
LT 0416 REV D • PRINTED IN USA
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
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