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DEMO MANUAL DC2278A
Description
LTC4281
Hot Swap Controller with
I2C Compatible Monitoring
Demonstration circuit 2278A features the LT C
®
4281 hot
swap controller. The LTC4281 is well suited to high power
applications because the precise monitoring capability
and accurate current limiting reduces the extremes in
which both loads and power supplies must safely oper-
ate. Non-volatile configuration allows for flexibility in the
autonomous generation of alerts and response to faults.
The LTC4281 provides a rich set of features to support
hot swap applications including:
n 12-/16-Bit ADC Monitors Current, Voltage, Power
and Energy
n I2C/SMBus Interface
n Non-Volatile Configuration and Logging Functions
n Generates Alerts on ADC Measurements Outside Limits
L, LT, LTC, LTM, Linear Technology, LTpowerPlay and the Linear logo are registered
trademarks and QuikEval is a trademark of Linear Technology Corporation. All other trademarks
are the property of their respective owners.
n Software Adjustable Current Limit with Foldback
n Three General Purpose Input/Outputs
Available in a 28-pin 4mm × 5mm QFN package, the
LTC4281 is showcased on DC2278A configured for a
12V, 50A application. The DC2278A-B has an included
programming socket to allow programming an LTC4281
for prototyping purposes prior to its permanent installation
on a PCB. The DC2278A-A does not have this socket. By
changing a few passive components, 2.9V to 30V applica-
tions can easily be evaluated.
Design files for this circuit board are available at
http://www.linear.com/demo/DC2278A
Figure 1. Proper Measurement Equipment Setup
DC2278 F01
TEST
LOADS
VARIABLE
POWER
SUPPLY
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DEMO MANUAL DC2278A
Quick start proceDure
performance summary
Specifications are at TA = 25°C
PARAMETER CONDITIONS VALUE
Input Supply Voltage Range 2.9V to 30V
Nominal Operating Voltage 12.0V
Overvoltage Lockout Nominal 15.0V
Undervoltage Lockout Nominal 11.1V
Output Current Limit Nominal 52.5A
Maximum Load Capacitance Nominal 10,000µF
Timer Expiration Period Nominal 4ms
Table. Power Input and Output Connections
NOMENCLATURE CONNECTOR DESCRIPTION
12VIN E1 12V Power In
12VOUT 50A E2 12V Power Out
GND E21 (Banana) Power Supply Common
Table 2. Test Points, Turrets
NOMENCLATURE TURRET DESCRIPTION
GPIO1 E3 GPIO1 Pin I/O
VCC E4 Internal VCC
12VOUT E5 12VOUT Monitor
12VIN E6 12VIN Monitor
ON (SHORT PIN) E7 ON Pin Monitor/Input
SCL E8 I2C Serial Clock Input
GND E9, E10, E15, E17 Ground
SDA E11 I2C Serial Data Input/Output
ALERT E12 ALERT Pin
GPIO2 E13 GPIO2 Pin I/O
GPIO3 E14 GPIO3 Pin I/O
EXT 5V E16
TIMER E18 TIMER Pin
UV E19 UV Pin
OV E20 OV Pin
GATE E22 GATE Pin
Table 3. LED Indicators
NOMENCLATURE LED DESCRIPTION
IN D1 (Green) Input Power Indicator
OUT D2 (Green) Output Power Indicator
GPIO1 D3 (Green) GPIO1 Logic Low Indicator
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DEMO MANUAL DC2278A
Quick start proceDure
Table 4. Jumpers
NOMENCLATURE JUMPER DESCRIPTION
CLK: INT, EXT JP1 Internal/External Clock Select
ON: INTVCC, FLOAT, GND JP2 ON Input Select, VCC, Float (External), GND
ADR0: H, NC, L JP3 Address Pin ADRO Select
ADR1: H, NC, L JP4 Address Pin ADR1 Select
ADR2: H, NC, L JP5 Address Pin ADR2 Select
WRITE PROTECT: LOCK, WRITE JP6 Write Protect for EEPROM
Operating Principles
The LTC4281 is a low voltage, high current hot swap
controller that has a 2.9V to 33V operating range and
a 45V absolute maximum voltage for the VDD pin. This
demo circuit is populated for 12V operation, but it can
easily be readjusted for any voltage between 2.9V and 30V
by replacing R1, R2, and R7 (top resistors in the UV/OV
divider and the FB divider). The DC2278A as supplied by
the factory is populated with a pair of PSMN1R5-30BLE
MOSFETs in D2PAK packages. A total of five 2.5mΩ sense
resistors are used, providing typically 50A of load current.
The current limit and circuit breaker thresholds can be
adjusted by changing the sense resistors R52, R57, R62,
R67 and R72 and/or the value of ∆VSENSE via addressable
registers in the LTC4281. Several locations for MOSFET
packages as well as additional sense resistors are avail-
able on the front and rear of the PCB for higher current
configurations.
Quick Start Procedure (Without Software)
DC2278A is easy to set up to evaluate the performance of
the LTC4281. Refer to Figure 1 for proper measurement
equipment setup and follow the procedure below.
WARNING
The DC2278A is capable of operation in excess of 50A. At
this current and power level, there is a danger of serious
personal injury and equipment damage if proper techniques
are not used. All cabling between the power supply and the
load should be capable of handling the current levels used.
Additionally, the high currents and fast transients can
cause unexpected voltage drops in cables connecting the
test equipment to the DC2278A due to parasitic resistance
and inductance. The cable drops may cause ground loops
for the current via various cables and scope probes. This
will cause unexplained ringing, distorted oscilloscope
waveforms, voltage and current spikes, and signals ap-
pearing to be below ground.
Table 5. Connectors
NOMENCLATURE CONNECTOR DESCRIPTION
QuikEval™ J1 Connection for DC590 Aux Demo Board
DC1613 J2 Connection for DC1613 Aux Demo Board
Table 3. LED Indicators
SOCKET POWER ON D4 (Red) Programming Socket SKT1 Powered
ALERT D5 (Red) ALERT Pin Logic Low
SCL D6 (Green) Serial Clock Active
SDA D7 (Green) Serial Data Active
GPIO3 D8 (Green) GPIO3 Logic Low
GPIO2 D9 (Green) GPIO2 Logic Low
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DEMO MANUAL DC2278A
Quick start proceDure
A common sneak path for current is the third wire
grounds used on power cords of test equipment in use.
Using ground lifting connectors at the wall outlet won’t
necessarily alleviate these effects since most equipment
has line bypassing capacitors between the mains voltage
and local chassis ground. Isolating test equipment using
line isolation transformers with low primary to secondary
capacitance is recommended. Probe ground leads may
intercept induced fields from the high current paths and
should be minimized or avoided
Another method to remove these artifacts is the use of
a differential scope probe connected between the signal
to be observed and a ground connection located close to
the point of measurement.
Also be careful to not allow an open ground from the
power supply or load to cause return current through the
grounds of the various devices connected to the demo
board. This may present a fire hazard or cause damage
to the test equipment.
Jumper Positions
JUMPER NAME POSITION
JP1 CLK EXT
JP2 ON INTVCC
JP3 ADR0 NC
JP4 ADR1 NC
JP5 ADR2 NC
JP6 WRITE PROTECT LOCK
Powering Up
Connect power supply capable of 60A at 0V to 20V to
the 12V input as shown in Figure 1. Verify cabling shown
in extra bold lines is capable of carrying 60A safely. The
GND connection does not handle high current so no high
current cabling is required.
Generally, an electronic load will be used. If this is true,
use it in the constant resistance mode. Use in constant
current will prevent start up because of current foldback
in the LTC4281. Current foldback is used to minimize
dissipation in the MOSFETs used as pass devices with
the LTC4281. To affect this, current is initially limited to
approximately 1/3 of full limit until the output voltage is
above 10V. If a constant current load is used and set to
50A, the LTC4281 will not start up and a current fault will
be reported.
UV/OV Thresholds
With no load on the output, slowly increase the voltage
on the input to the board. Observe the input voltage when
LED D2 (OUT) illuminates. This voltage should be between
10.7V and 11.4V. Continue increasing the voltage until D2 is
extinguished. This should occur between 14.4V and 15.3V.
Output Voltage Slew Rate
With no load connected, observe the output voltage
between turret 12VOUT (E5), and GND. Apply 12V to the
12VIN connector. The output voltage should slew from 0V
to 12V in 10ms to 25ms.
Output Current Limit
Turn off power supply and connect electronic load to the
DC2278A as shown in Figure 1. Disable electronic load.
Adjust power supply to 12V and verify its current level is
set to >60A.
Slowly increase conductance of the electronic load while
monitoring current. As the load increases to around 50A,
the output voltage and current will fall to zero. Note the
current where this occurs. This should be 47.5A to 52.5A.
Ability to Charge Output Capacitor
Turn off power supply and disconnect electronic load.
Replace load with a 10,000µF capacitor rated at 15V or
greater. Turn on power supply and observe that the output
voltage rises to 12V indicating the DC2278A has connected
to the load and successfully charged the output capacitance.
Monitor the current during the period when the capacitor
is charging, it should be a maximum of 12A.
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DEMO MANUAL DC2278A
Quick start proceDure
Software Control with LTpowerPlay
®
LTpowerPlay is a convenient PC software GUI that gives
complete access to the registers of the LTC4281, and
many other Linear Technology power system management
parts. Use it in offline mode to build a system configura-
tion file even with no hardware plugged-in, and use it
with hardware connected to configure and debug your
application. LTpowerPlay communicates using the I2C bus
in the demo system (covered in this manual), or in your
real-world product environment. It provides unprecedented
control over the Linear Technology ICs on the I2C bus. Use
it during board bring-up to tune and optimize the power
system parameters. Use it during system debug to view
critical system information and troubleshoot board design
or manufacturing issues. LTpowerPlay includes extensive
help and documentation under the help menu. Online help
includes quick start videos and tutorials, and detailed tech-
nical documentation from the Linear Technology website.
Getting started with L
TpowerPlay is easy. Simply download
and install the PC software from here:
http//www.linear.com/ltpowerplay
Figure 2. DC2278A-A Demo Board Connected to DC1613 I2C-to-USB Converter
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DEMO MANUAL DC2278A
Quick start proceDure
The DC1613 USB-to-I2C adapter interfaces the PC running
LTpowerPlay to the DC2278A board. Connect the DC1613
adapter to the PC through a USB cable, and connect the
DC2278A board through the ribbon cable to connector
J2 (Figure2).
Launch the LTpowerPlay GUI on the PC. The software
identifies the DC1613 controller, then the DC2278A board,
and begins communicating through the I2C bus with the
LTC4281. Once this communication has been established,
the GUI displays its main window (Figure 3).
The LTpowerPlay GUI divides information into separate
panes in the window. On the left is the system tree pane
(Figure 4), displaying a list of all Linear Technology devices
identified on the I2C bus. For a single LTC4281 device,
the tree is small, but if other supported devices are pres-
ent on the I2C bus, LTpowerPlay will add them. Click on
a device in this list to selectively access it. Information in
other panes pertains to the selected device.
LTpowerPlay System Tree
Figure 3. LTpowerPlay GUI Window
Figure 4. LTpowerPlay System Tree
To the right of the system tree is the configuration register
pane. The Figure 5 view shows all of the writable user-
configurable registers available on the selected device.
The GUI offers clickable buttons and fields to edit the
information in these registers.
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DEMO MANUAL DC2278A
Quick start proceDure
Update register contents by clicking or typing to change
the desired registers. Then selecting the PC to RAM button
in the top toolbar (Figure 6). LTpowerPlay writes changes
to the updated registers.
Figure 5. LTpowerPlay Configuration Registers
Right of center in LTpowerPlay is the telemetry pane
(Figure 7), displaying read-only information contained in
the status registers of the selected part. The GUI periodi-
cally polls the I2C bus and updates the telemetry content,
along with a user-friendly interpretation of the bits.
Figure 6. PC to RAM Button
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DEMO MANUAL DC2278A
Quick start proceDure
Figure 7. LTpowerPlay Telemetry
In the upper right corner of LTpowerPlay is the chip dash-
board pane (Figure 8), displaying a graphical representation
of the part status in a friendly, easy-to-understand format.
The meter in the upper left of the panel displays the static
input energy to the card in watts. The small dials in the
center of the input energy meter display the energy used
in kilojoules. The VSOURCE meter displays the voltage
at the SOURCE pin of the LTC4281, which is the same
as VOUT. The Input meter displays the voltage input at
the VDD pin of the LTC4281. VSENSE indicates the input
current derived by dividing the voltage measured across
the sense resistor by the value of the sense resistor. The
power meter displays the SOURCE voltage multiplied
by the current sense voltage and scaled to indicate the
power in watts. VGPIO3 displays the voltage at GPIO3
when it is configured as an analog input. The FET Status
annunciators show the status of the pass MOSFETs as
described in the FET-Bad Fault section of the data sheet.
GPIO1, GPIO2 and GPIO3 show the status of the general
purpose input/output pins.
On the lower right of the GUI window is the telemetry
plot pane (Figure 9). By selecting various measurement
functions in the telemetry pane, a graphic display of that
function versus time is displayed. This gives an instant
indication on how that function varies with time.
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DEMO MANUAL DC2278A
Quick start proceDure
Figure 8. LTpowerPlay Chip Dashboard
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DEMO MANUAL DC2278A
Quick start proceDure
Figure 9. LTpowerPlay Telemetry Plot
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DEMO MANUAL DC2278A
Quick start proceDure
Figure 10. LTC4281 RAM and Non-Volatile Memory
RAM
LTC4281 CHIP
COMPUTER WITH
LTpowerPlay
STORE
RESTORE
LTC4281
LOGIC
EEPROM
I2CBUS
Figure 11. Read Write NVM Buttons on Toolbar
The LTC4281 is highly configurable through its register
set. Refer to the LTC4281 data sheet for a complete
discussion of the registers and functions available. Get
immediate access to detailed help for the selected register
in LTpowerPlay by pressing the F1 key on your keyboard.
The LTC4281 features non-volatile EEPROM that holds
device configuration information and a snapshot of past
fault information. When the part receives power it executes
a power-on reset, and restores the contents of the EEPROM
to its operating RAM. Following this power-on restore, op-
erating RAM can be modified with I2C bus commands that
modify the part behavior. These modifications are effected
by using the PC>RAM button in the toolbar. Also included
in the toolbar are buttons for reading the internal RAM
data on the PC by using the RAM>PC button on the tool
bar. Similarly, there are buttons for moving the contents
of the RAM to the NVM (EEPROM) and vice versa using
the RAM>NVM and NVM>RAM buttons on the toolbar.
Programming Socket
The DC2278A-B board includes a programming socket.
This socket in conjunction with the LTpowerPlay software
GUI and DC1613 USB-to-I2C adapter may be used to
program the EEPROM of multiple LTC4281 ICs prior to
their installation on a PC board.
Please refer to Application Note 145, http://cds.linear.com/
docs/en/application-note/AN145f.pdf, and refer to Option
1A. Use the device address 0x88, which is the address to
which the programming socket is hard wired. Also verify
that the LTC4281 already soldered on the board (U1) is
set to a different address than 0x88 to prevent a conflict.
Follow the instructions for Option 1A on page 3 of
Application Note 145.
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DEMO MANUAL DC2278A
parts List
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
1 2 C1, C8 CAP., OPTION, ALUM. ELECT., SMD OPTION
2 2 C2, C3 CAP., 33pF, X7R, 16V, 5%, 0603 AVX, 0603YC330JAT2A
3 1 C4 CAP., OPTION, 0603 OPTION
4 2 C5, C9 CAP., 0.1µF, X7R, 16V, 10%, 0603 AVX, 0603YC104KAT2A
5 1 C6 CAP., 4.7µF, X5R, 16V, 10%, 0603 TDK, C1608X5R1C475K080AC
6 1 C7 CAP., 0.068µF, X7R, 16V, 10%, 0603 AVX, 0603YC683KAT2A
7 1 C10 CAP., 0.027µF, X7R, 50V, 10%, 0603 AVX, 06035C273KAT2A
8 1 C11 CAP., 0.1µF, X7R, 25V, 20%, 0603 TDK, C1608X7R1E104M080AA
9 1 C12 CAP., 0.022µF, X7R, 50V, 5%, 0805 KEMET, C0805C223J5RACTU
10 7 D1–D3, D6–D9 LED, GREEN, WATERCLEAR, 0805 WURTH ELEKTRONIK, 150080GS75000
11 2 D4, D5 LED, RED, WATER CLEAR, 2 PIN SMD LITE-ON TECHNOLOGY CORP, LTST-C170EKT
12 4 D10–D13 DIODE, TVS, 28V, 1500W, SMC DIODES INC., SMCJ28A-13-F
13 2 E1, E2 LUG, TONGUE, OFFSET FLOATING, ONE HOLE PENCOM, EL1664
14 19 E3–E20, E22 TEST POINT, TURRET, 0.064" MTG. HOLE, 0.125"
THICK PCB
MILL-MAX, 2308-4-00-80-00-00-07-0
15 1 E21 CONN., BANANA JACK, FEMALE, THT, NON-
INSULATED, SWAGE
KEYSTONE, 575-4
16 1 J1 CONN., HDR., MALE, 2x7, 2mm, THT, VERT,
SHROUDED
MOLEX, 87831-1420
17 1 J2 CONN., HDR., SHROUDED, 2X6, 2mm, THT, VERT FCI, 98414-G06-12ULF
18 2 JP1, JP6 CONN., HDR., MALE, 1X3, 2mm, THT, STRT SAMTEC, TMM-103-02-L-S
19 4 JP2–JP5 CONN., HDR., MALE, 1X4, 2mm, THT, STRT SAMTEC, TMM-104-02-L-S
20 1 LB1 LABEL SPEC, DEMO BOARD SERIAL NUMBER BRADY, THT-96-717-10
21 4 MP1–MP4 BUMPER, RECESSED, #4 SCREW, BLACK KEYSTONE, 727
22 4 MP5–MP8 WASHER, FLAT, #4, SS 18-8 PENCOM, WA1021
23 4 MP9–MP12 SCREW, MACHINE, #4-40 X 1/2, PHILLIPS PH, SS PENCOM, SC3389
24 4 MP13–MP16 WASHER, LOCK, INT. TOOTH, #4, SS PENCOM, WA1196
25 4 MP17–MP20 NUT, HEX, #4-40, SS 18-8 PENCOM, NU1043
26 2 MP21, MP22 SCREW, MACHINE, 1/4-20 X 7/8, HEX WASHER
HEAD, SS
PENCOM, SE6037
27 4 MP23–MP26 WASHER, FLAT, SS 18-8, 1/4 IN. PENCOM, WA3491
28 2 MP27, MP28 WASHER, LOCK, INT. TOOTH, 1/4 IN., SS PENCOM, WA1374
29 2 MP29, MP30 NUT, HEX, 1/4-20, SS 18-8 PENCOM, NU1006
30 1 PCB1 PCB, DC2278A MAO BANG, 600-DC2278A
31 2 Q1, Q2 XSTR., MOSFET N-CHAN, 30V, 120A, D2PAK NXP SEMICONDUCTORS, PSMN1R5-30BLE
32 3 Q3–Q5 XSTR., MOSFET N-CH, 60V, 300mA, SOT-23 VISHAY, 2N7002K-T1-GE3
33 1 Q6 TRANSISTOR, MOSFET, N-CH., SO-10, OPTIONAL ST MICROELECTRONICS, STV300NH02L
34 2 Q7, Q8 MOSFET, N-CH, OPTION OPTION
35 1 Q9 TRANSISTOR, MOSFET, N-CH., SOT-669-
OPTIONAL
NXP
, PSMN2R0-30YLE
36 1 R1 RES., 34.8kΩ, 1%, 1/10W, 0603 VISHAY, CRCW060334K8FKEA
37 1 R2 RES., 1.18kΩ, 1%, 1/10W, 0603 YAGEO, RC0603FR-071K18L
38 1 R3 RES., 3.4kΩ, 1%, 1/10W, 0603 NIC, NRC06F3741TRF
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DEMO MANUAL DC2278A
parts List
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
39 5 R4–R6, R17, R18 RES., 10kΩ, 5%, 1/4W, 1206 PANASONIC, ERJ8GEYJ103V
40 1 R7 RES., 30.1kΩ, 1%, 1/10W, 0603 PANASONIC, ERJ3EKF3012V
41 4 R8, R10, R11, R21 RES., 3.01kΩ, 1%, 1/10W, 0603 VISHAY, CRCW06033K01FKEA
42 8 R9, R19, R20, R23, R24, R34–
R36
RES., OPTION, 0603 OPTION
43 4 R12–R14, R22 RES., 5.11kΩ, 1%, 1/10W, 0603 PANASONIC, ERJ3EKF5111V
44 8 R15, R16, R25, R26, R31–R33,
R38
RES., 0Ω, 1/10W, 0603 VISHAY, CRCW06030000Z0EA
45 6 R27–R30, R39, R73 RES., 10Ω, 5%, 1/10W, 0603 PANASONIC, ERJ3GEYJ100V
46 1 R37 RES., 2kΩ, 1%, 1/10W, 0603 NIC, NRC06F2001TRF
47 24 R40, R41, R43–R46, R48, R49,
R77–R79, R81–R86, R88–R91,
R93–R95
RES., OPTION, 0402 OPTION
48 5 R42, R47, R80, R87, R92 RES., OPTION, 2512 OPTEK TECHNOLOGY (TT ELECTRONICS),
LRMAT2512-R003FT4
49 20 R50, R51, R53–R56, R58–R61,
R63–R66, R68–R71, R74, R75
RES., 1Ω, 1%, 1/16W, 0402 VISHAY, CRCW04021R00FKED
50 5 R52, R57, R62, R67, R72 RES., METAL ELEMENT, 0.0025Ω, 1%, 3W, 2512 TT ELECTRONICS, ULRG3-2512-R0025-F-LF-
SLT
51 1 R76 RES., 59kΩ, 1%, 1/10W, 0603 VISHAY, CRCW060359K0FKEA
52 1 SKT1 CONN., SOCKET, CLAMSHELL, 28 LEAD, SMT,
5x4mm QFN
PLASTRONICS, 28QN50S25040
53 6 TP1, TP2, TP4, TP5, TP7, TP8 TESTPOINT, PCB COPPER FEATURE N/A
54 1 U1 IC, HI-CURRENT HOT SWAP CONTROLLER, QFN LINEAR TECHNOLOGY, LTC4281IUFD#PBF
55 1 U2 IC, MEMORY, EEPROM, 2k-bit, 400kHz, TSSOP-8 MICROCHIP, 24LC025-I/ST
56 6 XJP4–XJP6, XJP10–XJP12 CONN., SHUNT, FEMALE, 2 POS, 2mm SAMTEC, 2SN-BK-G
57 1 Y1 CRYSTAL, 4 MHz, 18pF, ±50ppm,
11.4mmx4.7mm, 2Pad SMD
ABRACON CORPORATION, ABLS-4.000MHZ-
B4-T
58 1 Y2 RESONATOR, 4MHz, SMT, OPTION MURATA, CSTCR4M00G53-R0 (OPTION)
59 3 Z1–Z3 DIODE, ZENER, 5.1V, 500mW, SOD-123 FAIRCHILD, MMSZ5231B
14
dc2278af
DEMO MANUAL DC2278A
schematic Diagram
A
A
B
B
C
C
D
D
E
E
4 4
3 3
2 2
1 1
SCL
GPI01
= HIGH-CURRENT CONNECTIONS
CONNECTIONS TO PAGES 2 AND 3
GND
GPI02
GPI03
IN
GPIO3 GPIO2
GPIO1
OUT
(300K)
(0.1u)
ON
INTVCC
FLOAT
GND
WRITE PROTECTADR0ADR1ADR2
LOCK
WRITE
H
NC
L
H
NC
L
+12V IN
+12V OUT
+12V OUT
Quik Eval
DC2278A-B STUFFED
LTC SKU# SKT 1 ( PAGE 3 )
ASSEMBLY OPTIONS
NOT STUFFEDDC2278A-A
UNLESS OTHERWISE NOTED:
1. ALL RESISTORS THIS PAGE ARE 1% 0603.
2. ALL CAPACITORS THIS PAGE ARE 0603.
INT
EXT
CLK
DC 1613
ALERT SCL SDA
+12V IN
ON
GND
SDA
SCL
ALERT
EXT 5V
GND
(SHORT PIN)
INT VCC
TIMER
OV UV
OPT
GND
GND
50 AMPS
TM
HIGH CURRENT HOT SWAP CONTROLLER
WITH I2C COMPATIBLE MONITORING AND EEPROM
+5V
+5V
+5V
+5V
+5V
+5V
SOURCE
INPUT
SENSE-
ADC-
SDA
SCL
SENSE+
ADC+ GATE
DATE:
IC NO.
SHEET OF
TITLE: DEMO CIRCUIT SCHEMATIC,
APPROVALS
PCB DES.
APP ENG.
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
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
SIZE:
SKU NO.
SCHEMATIC NO. AND REVISION:
PCA ASS'Y DWG:
14
M.HAWKINS
BOB SMITH
710-DC2278A_REV02
DC2278A-B
DC2278A-A
LTC4281-UFD
705-DC2278A_REV02
Tuesday, May 10, 2016
11X17
DATE:
IC NO.
SHEET OF
TITLE: DEMO CIRCUIT SCHEMATIC,
APPROVALS
PCB DES.
APP ENG.
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
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
SIZE:
SKU NO.
SCHEMATIC NO. AND REVISION:
PCA ASS'Y DWG:
14
M.HAWKINS
BOB SMITH
710-DC2278A_REV02
DC2278A-B
DC2278A-A
LTC4281-UFD
705-DC2278A_REV02
Tuesday, May 10, 2016
11X17
DATE:
IC NO.
SHEET OF
TITLE: DEMO CIRCUIT SCHEMATIC,
APPROVALS
PCB DES.
APP ENG.
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
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
SIZE:
SKU NO.
SCHEMATIC NO. AND REVISION:
PCA ASS'Y DWG:
14
M.HAWKINS
BOB SMITH
710-DC2278A_REV02
DC2278A-B
DC2278A-A
LTC4281-UFD
705-DC2278A_REV02
Tuesday, May 10, 2016
11X17
R12
5.11k
E6
R18
10k
E13
E21
JP6
1
3
2
R10
3.01k
R11
3.01k
R3
3.4k
D3
GREEN
21
C3
33pF
E18
R1
34.8k
E3
U2
24LC025-I/ST
SDA 5
VCC 8
A0
1
A1
2
A2
3
VSS
4
WP 7
SCL 6
D5
RED
21
E2
Z2 MMSZ5231B
5.1V
1 2
E1
R20
OPT
C11
0.1uF
Y2
13
2
Q5
2N7002
3
1
2
E12
R19
OPT
R22
5.11k
R5
10k
R6 10k
R26 0
R24
OPT
E10
C2
33pF
C4
OPT
D11
SMCJ-28A
2 1
TP1
JP2
1
2
3
4
E7
E16
JP5
1
2
3
4
JP1
1
3
2
E8
R8 3.01k
Q4
2N7002
3
1
2
R16 0
R2
1.18k
D8
GREEN
21
C9
0.1uF
Z1
MMSZ5231B
5.1V
1
2
J2
AUXP 1
SDA 2
GND 3
SCL 4
LGKPWR 5
ALERTB 6
GPIO_1 7
OUTEN_0 8
OUTEN_1 9
GND 10
AUXSCL 11
AUXSDA 12
E14
R14
5.11k
Z3 MMSZ5231B
5.1V
1 2
J1
VUNREG 1
GND 3
MISO 5
MOSI/SDA 7
EESDA 9
EESCL 11
GND 13
VCCIO 2
SCK/SCL 4
CS 6
GND 8
EEVCC 10
EEGND 12
GPIO 14
C6
4.7uF
R23
OPT
D2
GREEN
21
D1
GREEN
21
E17
TP2
E5
U1
LTC4281-UFD
UV
28
OV
2
SDAI
12
SDAO
13
ALERT
15
INTVCC
5
TIMER
6
ADR0
9
ADR1
10
ADR2
11
WP
4
GND
3
CLKIN 8
GPIO3 16
GPIO2 17
GPIO1 18
FB 20
ON 1
SOURCE 21
GATE 22
ADC- 23
SENSE- 24
ADC+ 26
SCL
14
SENSE+ 25
VDD 27
CLKOUT 7
GND
19
EXPOSED PAD
29
R4 10k
C7
0.068uF
E4
D6
GREEN
21
Q3
2N7002
3
1
2
R25 0
JP3
1
2
3
4
JP4
1
2
3
4
Y1
4 MHz
12
E19
D9
GREEN
21
R7
30.1k
R15 0
R21
3.01k
R13
5.11k
R17
10k
D7
GREEN
21
E20
E15
E9
R9
OPT
E11
INTVCC
INTVCC
GPIO3 GPIO2
GPIO2
GPIO3
SCL
SDA
SDA
SDA
SCL
SCL
GPIO1
GPIO1
GPIO2
15
dc2278af
DEMO MANUAL DC2278A
schematic Diagram
A
A
B
B
C
C
D
D
E
E
4 4
3 3
2 2
1 1
=HIGH CURRENT CONNECTIONS
"RS2"
UNLESS OTHERWISE NOTED:
1. ALL RESISTORS THIS PAGE ARE 1% 0402.
2. ALL CAPACITORS THIS PAGE ARE 0603.
3. ALL 0.003 OHM SENSE RESISTORS ARE SIZE 2512.
PRIMARY SIDE
GATE
ADC+
SENSE+ ADC-
SENSE-
PRIMARY SIDE
"Q2"
(TO BOTTOM SIDE)
(OPT)
(OPT) NICHICON P/N UVR1E102MPD
OR EQUIVALENT
NICHICON P/N UVR1E102MPD
OR EQUIVALENT
1000 uF
1000 uF
OPT OPT
HIGH CURRENT HOT SWAP CONTROLLER
(OPT)
(OPT)
(FROM TOP SIDE)
(OPT)
SECONDARY SIDE
"Q2"
WITH I2C COMPATIBLE MONITORING AND EEPROM
INPUT
SOURCE
ADC+
SENSE+
GATE
SENSE-
ADC-
INPUT
DATE:
IC NO.
SHEET OF
TITLE: DEMO CIRCUIT SCHEMATIC,
APPROVALS
PCB DES.
APP ENG.
Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 McCarthy Blvd.
LTC Confidential-For Customer Use Only
SCALE = NONE
www.linear.com
SIZE:
SKU NO.
SCHEMATIC NO. AND REVISION:
PCA ASS'Y DWG:
24
M.HAWKINS
BOB SMITH
710-DC2278A_REV 02
DC2278A-B
DC2278A-A
LTC4281-UFD
705-DC2278A_REV02
N/A
Tuesday, May 10, 2016
DATE:
IC NO.
SHEET OF
TITLE: DEMO CIRCUIT SCHEMATIC,
APPROVALS
PCB DES.
APP ENG.
Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 McCarthy Blvd.
LTC Confidential-For Customer Use Only
SCALE = NONE
www.linear.com
SIZE:
SKU NO.
SCHEMATIC NO. AND REVISION:
PCA ASS'Y DWG:
24
M.HAWKINS
BOB SMITH
710-DC2278A_REV 02
DC2278A-B
DC2278A-A
LTC4281-UFD
705-DC2278A_REV02
N/A
Tuesday, May 10, 2016
DATE:
IC NO.
SHEET OF
TITLE: DEMO CIRCUIT SCHEMATIC,
APPROVALS
PCB DES.
APP ENG.
Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 McCarthy Blvd.
LTC Confidential-For Customer Use Only
SCALE = NONE
www.linear.com
SIZE:
SKU NO.
SCHEMATIC NO. AND REVISION:
PCA ASS'Y DWG:
24
M.HAWKINS
BOB SMITH
710-DC2278A_REV 02
DC2278A-B
DC2278A-A
LTC4281-UFD
705-DC2278A_REV02
N/A
Tuesday, May 10, 2016
R40 OPT
R55 1
Q7
N-CHANNEL UNIVERSAL 1
23
R44
OPT
R60 1
Q1
PSMN1R5-30BLE 1
34
R56 1
R45 OPT
R71 1
D13
SMCJ-28A
2 1
R79 OPT
R50 1 R51 1
R95 OPT
Q6
STV300NH02L
1
5
6
7
8
2
3
9
10
11
4
TP5
Q9
PSMN2R0-30YLE
4
2
3
51
Q2
PSMN1R5-30BLE 1
34
R86 OPT
R78 OPT
TP4
R61 1
+
C8
OPT
12
TP7
R74 1
R68 1
R57
0.0025
R65 1
R94 OPT
R52
0.0025
R89 OPT
R75 1
R85 OPT
R63 1
R27 10
Q8
N-CHANNEL UNIVERSAL
1
23
+
C1
OPT
12
R42
OPT
R47
OPT
R80
OPT
R92
OPT
R73 10
R43 OPT
R69 1
C10 0.027uF
50V
R29 10
R53 1
R87
OPT
D12
SMCJ-28A
2 1
R72
0.0025
R67
0.0025
R59 1
R54 1
R93 OPT
R58 1
R81 OPT
R90 OPT
R41
OPT
R82 OPT
R28 10
R46 OPT
E22
R64 1
R30 10
R88 OPT
R70 1
R62
0.0025
R77 OPT
R49 OPT
R83 OPT
R91 OPT
R84 OPT
R76 59k
R39 10
D10
SMCJ-28A
2 1
TP8
R66 1
R48 OPT
C12 0.022uF
B
SENSE-
GATE
ADC+
SENSE+
ADC-
B
16
dc2278af
DEMO MANUAL DC2278A
schematic Diagram
A
A
B
B
C
C
D
D
E
E
4 4
3 3
2 2
1 1
OPTIONAL PROGRAMMING SOCKET,
SOCKET
POWER
0N
UNLESS OTHERWISE NOTED:
1. ALL RESISTORS THIS PAGE ARE 0603.
INSTALLED ON -B ASSEMBLY OPTION
SOCKET POWER
HIGH CURRENT HOT SWAP CONTROLLER
WITH I2C COMPATIBLE MONITORING AND EEPROM
+5V
SDA
SCL
DATE:
IC NO.
SHEET OF
TITLE: DEMO CIRCUIT SCHEMATIC,
APPROVALS
PCB DES.
APP ENG.
Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 McCarthy Blvd.
LTC Confidential-For Customer Use Only
SCALE = NONE
www.linear.com
SIZE:
SKU NO.
SCHEMATIC NO. AND REVISION:
PCA ASS'Y DWG:
34
M.HAWKINS
BOB SMITH
710-DC2278A_REV 02
DC2278A-B
DC2278A-A
LTC4281-UFD
705-DC2278A_REV02
8.5X11
Tuesday, May 10, 2016
DATE:
IC NO.
SHEET OF
TITLE: DEMO CIRCUIT SCHEMATIC,
APPROVALS
PCB DES.
APP ENG.
Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 McCarthy Blvd.
LTC Confidential-For Customer Use Only
SCALE = NONE
www.linear.com
SIZE:
SKU NO.
SCHEMATIC NO. AND REVISION:
PCA ASS'Y DWG:
34
M.HAWKINS
BOB SMITH
710-DC2278A_REV 02
DC2278A-B
DC2278A-A
LTC4281-UFD
705-DC2278A_REV02
8.5X11
Tuesday, May 10, 2016
DATE:
IC NO.
SHEET OF
TITLE: DEMO CIRCUIT SCHEMATIC,
APPROVALS
PCB DES.
APP ENG.
Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 McCarthy Blvd.
LTC Confidential-For Customer Use Only
SCALE = NONE
www.linear.com
SIZE:
SKU NO.
SCHEMATIC NO. AND REVISION:
PCA ASS'Y DWG:
34
M.HAWKINS
BOB SMITH
710-DC2278A_REV 02
DC2278A-B
DC2278A-A
LTC4281-UFD
705-DC2278A_REV02
8.5X11
Tuesday, May 10, 2016
D4
RED
21
R36 OPT
R33
0
C5
0.1uF
SKT1
SOCKET
UV
28
OV
2
SDAI
12
SDAO
13
ALERT
15
INTVCC
5
TIMER
6
ADR0
9
ADR1
10
ADR2
11
WP
4
GND
3
CLKIN 8
GPIO3 16
GPIO2 17
GPIO1 18
FB 20
ON 1
SOURCE 21
GATE 22
ADC- 23
SENSE- 24
ADC+ 26
SCL
14
SENSE+ 25
VDD 27
CLKOUT 7
GND
19
EXPOSED PAD
29
R35 OPT
R32
0
R31
0
R38
0
R37
2k
R34 OPT
17
dc2278af
DEMO MANUAL DC2278A
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
A
A
B
B
C
C
D
D
E
E
4 4
3 3
2 2
1 1
PCA ADDITIONAL PARTS
HIGH CURRENT HOT SWAP CONTROLLER
WITH I2C COMPATIBLE MONITORING AND EEPROM
Tuesday, May 10, 2016
DATE:
IC NO.
SHEET OF
TITLE: DEMO CIRCUIT SCHEMATIC,
APPROVALS
PCB DES.
APP ENG.
Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 McCarthy Blvd.
LTC Confidential-For Customer Use Only
SCALE = NONE
www.linear.com
SIZE:
SKU NO.
SCHEMATIC NO. AND REVISION:
PCA ASS'Y DWG:
44
M.HAWKINS
BOB SMITH
710-DC2278A_REV 02
DC2278A-B
DC2278A-A
LTC4281-UFD
705-DC2278A_REV02
8.5X11
DATE:
IC NO.
SHEET OF
TITLE: DEMO CIRCUIT SCHEMATIC,
APPROVALS
PCB DES.
APP ENG.
Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 McCarthy Blvd.
LTC Confidential-For Customer Use Only
SCALE = NONE
www.linear.com
SIZE:
SKU NO.
SCHEMATIC NO. AND REVISION:
PCA ASS'Y DWG:
44
M.HAWKINS
BOB SMITH
710-DC2278A_REV 02
DC2278A-B
DC2278A-A
LTC4281-UFD
705-DC2278A_REV02
8.5X11
DATE:
IC NO.
SHEET OF
TITLE: DEMO CIRCUIT SCHEMATIC,
APPROVALS
PCB DES.
APP ENG.
Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 McCarthy Blvd.
LTC Confidential-For Customer Use Only
SCALE = NONE
www.linear.com
SIZE:
SKU NO.
SCHEMATIC NO. AND REVISION:
PCA ASS'Y DWG:
44
M.HAWKINS
BOB SMITH
710-DC2278A_REV 02
DC2278A-B
DC2278A-A
LTC4281-UFD
705-DC2278A_REV02
8.5X11
MP4 BUMPER, RECESSED,#4 SCREW,BLACK
MP6 WASHER,FLAT,#4,SS 18-8
MP7 WASHER,FLAT,#4,SS 18-8
MP5 WASHER,FLAT,#4,SS 18-8
MP8 WASHER,FLAT,#4,SS 18-8
MP21 SCREW, MACHINE,1/4-20 X 7/8,HEX WASHER HEAD, SS
MP9 SCREW, MACHINE,#4-40 X 1/2,PHILLIPS PH,SS
MP22 SCREW, MACHINE,1/4-20 X 7/8,HEX WASHER HEAD, SS
MP10 SCREW, MACHINE,#4-40 X 1/2,PHILLIPS PH,SS
MP11 SCREW, MACHINE,#4-40 X 1/2,PHILLIPS PH,SS
LB1 LABEL
MP23 WASHER, FLAT,SS 18-8,1/4 IN.
MP12 SCREW, MACHINE,#4-40 X 1/2,PHILLIPS PH,SS
PCB1 PCB, DC2278A REV02
MP24 WASHER, FLAT,SS 18-8,1/4 IN.
MP13 WASHER, LOCK,INT. TOOTH,#4,SS
MP25 WASHER, FLAT,SS 18-8,1/4 IN.
MP14 WASHER, LOCK,INT. TOOTH,#4,SS
MP26 WASHER, FLAT,SS 18-8,1/4 IN.
MP15 WASHER, LOCK,INT. TOOTH,#4,SS
MP16 WASHER, LOCK,INT. TOOTH,#4,SS
MP27 WASHER, LOCK,INT. TOOTH, 1/4 IN.,SS
MP28 WASHER, LOCK,INT. TOOTH, 1/4 IN.,SS
MP17 NUT, HEX,#4-40,SS 18-8
MP2 BUMPER, RECESSED,#4 SCREW,BLACK MP18 NUT, HEX,#4-40,SS 18-8
MP29 NUT, HEX,1/4-20,SS 18-8
MP1 BUMPER, RECESSED,#4 SCREW,BLACK
MP19 NUT, HEX,#4-40,SS 18-8
MP30 NUT, HEX,1/4-20,SS 18-8
MP3 BUMPER, RECESSED,#4 SCREW,BLACK
MP20 NUT, HEX,#4-40,SS 18-8
18
dc2278af
DEMO MANUAL DC2278A
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com
LINEAR TECHNOLOGY CORPORATION 2015
LT 0916 • 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
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
