Linear Technology DC1886A Quick setup guide

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dc1886af
DEMO MANUAL DC1886A
Description
LTC4232:
5A Integrated
Hot Swap Controller
Demonstration circuit 1886A features the LTC4232 5A
Integrated Hot Swap™ Controller. The LTC4232 is ideally
suited for demanding power distribution control in 2.9V
to 15V applications for hot board insertion protection,
high side power switching, and electronic circuit breaker
functions. The LTC4232 provides a rich set of features to
support Hot Swap applications including:
• 2%accurateundervoltageandovervoltageprotection
• Overtemperatureprotection
• Adjustableinrushcurrentcontrol
• Adjustable,10%accuratecurrentlimitwithprogram-
mable cutout time
performance summary
• Programmableoutputvoltageramprate
• Configurableforauto-retryorlatchoffonovercurrent
faults
• Powergoodandfaultoutputs
Available in a 16-lead 5mm × 3mm DFN package, the
LTC4232 is showcased on demonstration circuit 1886A,
configured for a 12V application. By changing a few pas-
sive components, 2.9V to 15V applications can easily be
evaluated.
Design files for this circuit board are available at
http://www.linear.com/demo
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
Hot Swap is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
(TA= 25°C)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VDD Input Supply Range 2.9 15 V
dVGATE/dt GATEPinTurn-OnRampRate 0.15 0.3 0.55 V/ms
RON MOSFET+SenseResistorOn-Resistance 15 33 50 mΩ
ILIM(TH) Current Limit Threshold VFB = 1.23V 5.0 5.6 6.1 A
ILIM(TH) Current Limit Threshold VFB=0V
VFB = 1.23V, RSET=20k
1.2
2.6
1.5
2.9
1.8
3.3
A
A
VTH OV,UV,FBPinThresholdVoltage VIN Rising 1.21 1.235 1.26 V
VUV(RTH) UVPinResetThresholdVoltage VUV Falling 0.55 0.62 0.7 V
VFB(HYST) FBPinPowerGoodHysteresis 10 20 30 mV
VTIMER(H) TIMERPinHighThreshold VTIMER Rising 1.2 1.235 1.28 V
VTIMER(L) TIMERPinLowThreshold VTIMER Falling 0.1 0.21 0.3 V
ITIMER(UP) TIMERPinPull-UpCurrent VTIMER=0 –80 –100 –120 µA
ITIMER(DN) TIMERPinPulldownCurrent VTIMER = 1.2V 1.4 2 2.6 µA
IGATE(UP) GatePull-UpCurrent GateDriveOn,VGATE = VOUT = 12V –18 –14 –29 µA
tD(AUTO-RET) Auto-RetryTurn-OnDelay 50 100 150 ms

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dc1886af
DEMO MANUAL DC1886A
Quick start proceDure
Figure 1. Proper Measurement Equipment Setup
Demonstration circuit 1886A is easy to set up to evalu-
ate the performance of the LTC4232. Refer to Figure 1
for proper measurement equipment setup and follow the
procedure below.
Demonstration Circuit 1886A has two user configurable
jumperoptions:
• JP1TIMERDURATION:Setto2msfortheinternal2ms
timer or 12ms determined by C1. C1 may be replaced
for other timer durations. (Default position: 12ms)
• JP2AUTORETRY:SettoONforauto-retryorOFFfor
latchoffonovercurrentfaults.(Defaultposition:OFF)
+
–
+
–
+
–
ADJ
POWER SUPPLY +–
TEST LOADS

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dc1886af
DEMO MANUAL DC1886A
Quick start proceDure
LEDs indicate the state of input power, output power, FAULT
andPG.LoadcurrentcanbemonitoredontheIMON turret,
whichhasagainof0.4V/AdeterminedbyRMON(20k).
Setanadjustablepowersupplycapableofsupplying10A
to 12V. Turn off power and connect the supply to the VDD
and GND turrets.
Connect a suitable load to the VOUT and GND turrets. This
load can be an electronic load or power resistors capable
ofdissipating100W.
NOTE:BecausetheLTC4232incorporatesfoldbackcur-
rent limiting, the nominal start-up current supplied to the
load is 1.5A and can be as low as 1.2A. This current limit
increaseslinearlyuntiltheFBpinexceeds0.6V(VOUT >
5.1V). An electronic constant current load set to 1.5A will
not permit the circuit to turn on unless it is gated on by the
PGsignal(aswouldbethecasewithaDC/DCconverter
controlledbythePGsignal).Resistiveloadingwillnot
have this problem.
Turn on the power supply, verify the input voltage is 12V.
Verify the output voltage and the load current, D2 and
D4 should both be lit (input voltage and output voltage,
respectively) and both D3 (F LT )andD5(PG)shouldbe
off.Onpower-up,observetheslopeofVOUT. This should
beintherangeof0.15to0.55V/ms,correspondingtoa
ramp-uptimeof22msto80msto12V.Withthecircuit
functioning, additional evaluations can now be performed.
OV/UV/PGthresholds:Settheinputsupplytozeroand
ramp the voltage slowly, observing the following events.
Above10.3V,thecircuitwillbeoutofUVlockoutandthe
outputshouldramp-up,lightingD4.Above10.9VtheFB
pinwillbepastitsthreshold,assertingthePGpinhighand
extinguishing D5. Increasing the supply past 15.8V will
engageOVlockout;D4willextinguishandD5willlight.
Note that the voltages indicated in this step are maximums,
taking into consideration the tolerances of the resistors
and the LTC4232 inputs.
CurrentLimitThresholds: With theinputsupply set to
12V, load the output with a 2.5Ω power resistor capable of
dissipating60W.Powershouldremainon,asthecurrent
willbebelowthe5.0Aminimumcurrentlimitthreshold.
Next,loadtheoutputwitha1.8Ωpowerresistor.Power
should be interrupted, as the current will be above the
6.1A maximum current limit threshold.

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DEMO MANUAL DC1886A
Quick start proceDure
Inrushintocapacitiveload:Oneofthemainfunctionsof
a hot swap circuit is to provide controlled ramp-up into a
capacitive load to avoid disturbing the input power supply.
Forthefollowingtests,ensurethattheAUTORETRYjumper
issettoOFFandtheTIMERDURATIONjumperissetto
12ms. To guarantee that current limit is never reached
during ramp-up into a capacitor, the current must be less
than the minimum current limit threshold of 1.2A when
thegateramprateisatitsmaximumvalueof0.55V/ms.
(Note that the minimum current limit threshold occurs
whentheFBpinisatzero.)
 C=I/(dV/dt)=1.2A/(0.55V/ms)=2182µF
Thus, the circuit will always power up successfully with a
2000µFcapacitoratVOUT, and observation of the TIMER
turret post will show that it never begins to ramp. Figure 2
showssuccessfulramp-upintoa1200µFcapacitor.Inrush
current is determined by ramp rate alone.
It is more complicated to find the smallest capacitor that is
guaranteed to prevent successful ramp-up, since the cur-
rent into the load capacitor is afunction of the scaled output
voltage at the FB pin. As a starting point, the minimum
ramprateof0.15V/msshouldproduceacurrentgreater
than the maximum current limit threshold of 1.8A (when
FBisatzero)toensurethatthetimerbeginstorampas
soon as the output begins to rise.
 C=I/(dV/dt)=1.8A/(0.15V/ms)=12000µF
Figure 2. Successful Ramp-Up into 1200µF
IOUT
1A/DIV
VOUT
5V/DIV
TIMER
1V/DIV

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dc1886af
DEMO MANUAL DC1886A
Quick start proceDure
ObservationoftheTIMERpinwillshowthatitbeginsto
ramp as soon as the output begins to ramp. At this ramp
rate, the output voltage will only be at 1.8V after 12ms,
andhencetheFBpinwillbeat0.21V,abovethepointat
which the current limit threshold begins to increase. If the
ramp-up becomes limited by the slew rate of the gate pin,
the output voltage will continue to rise and successfully
power up. However, if the ramp-up continues to be limited
by the current limit threshold, the timer will expire. Figure 3
showsunsuccessfulramp-upintoan8000µFcapacitor.
CurrentreachestheinitiallimitwhenFBisatzero.Once
FB rises above approximately 100mV the current (and
hence the output ramp rate) increases, however the timer
expires before the output reaches its final value.
The correct way to ensure successful power-up into an
output capacitance greater than 2000µF is to reduce
the ramp rate by installing a 1k resistor and a suitable
capacitor for RGATE and CGATE following the procedure in
the data sheet. Increasing the timer duration carries the
riskofexceedingtheSafeOperatingArea(SOA)ofthe
internalMOSFET.
Circuit Testing Notes: As in all high current testing, it is
agoodideatousetwistedpairpowerleadstominimize
circuitinductance.Understeploadssignificantvoltage
spikes can occur as a result of this inductance causing
false overvoltage or undervoltage trips. If there is sig-
nificant lead length between the power supply and the
DC1886A, add additional bulk capacitance across the VIN
and GND turrets. This capacitance may also be needed if
stepping the load results in significant voltage steps on
the input, particularly if performing tests of the circuit
breaker function.
Figure 3. Unsuccessful Ramp-Up into 8000µF
IOUT
1A/DIV
VOUT
5V/DIV
TIMER
1V/DIV

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DEMO MANUAL DC1886A
schematic Diagram
5 5
4 4
3 3
2 2
1 1
D D C C B B A A
ALL CAPACITORS ARE IN MICROFARADS, 0603.
NOTES: UNLESS OTHERWISE SPECIFIED 2. INSTALL SHUNTS AS SHOWN. 1. ALL RESISTORS ARE IN OHMS, 0402.
2ms 12ms
TIMER
OFF ON
AUTORETRY
DURATION
VOUT
VDD
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: [phone]
Milpitas, CA 95035 Phone: [phone] 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
1
LTC4232IDHC
09/08/2011, 11:34 AM 1 1
5A INTEGRATED HOT SWAP CONTROLLER
KIM T.
VLADIMIR O.
N/A
DEMO CIRCUIT 1886A
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: [phone]
Milpitas, CA 95035 Phone: [phone] 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
1
LTC4232IDHC
09/08/2011, 11:34 AM 1 1
5A INTEGRATED HOT SWAP CONTROLLER
KIM T.
VLADIMIR O.
N/A
DEMO CIRCUIT 1886A
SIZE DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: [phone]
Milpitas, CA 95035 Phone: [phone] 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
1
LTC4232IDHC
09/08/2011, 11:34 AM 1 1
5A INTEGRATED HOT SWAP CONTROLLER
KIM T.
VLADIMIR O.
N/A
DEMO CIRCUIT 1886A
REVISION HISTORY DESCRIPTION DATEAPPROVEDECO REV
VLADIMIR O.1ST PROTOTYPE
109-08-11
_
REVISION HISTORY DESCRIPTION DATEAPPROVEDECO REV
VLADIMIR O.1ST PROTOTYPE
109-08-11
_
REVISION HISTORY DESCRIPTION DATEAPPROVEDECO REV
VLADIMIR O.1ST PROTOTYPE
109-08-11
_
RSET OPT 0805 RSET OPT 0805
R10 226k R10 226k
R1 3.3k R1 3.3k
C1 1uF 25V C1 1uF 25V
E10
ISET
E10
ISET
E3
GND
E3
GND
R3 3.3k R3 3.3k
D2 LN1351C
(GREEN)
D2 LN1351C
(GREEN)
2 1
E5
UV
E5
UV
R4 150k R4 150k
+
COUT2 OPT
+
COUT2 OPT
C2 0.1uF 16V C2 0.1uF 16V
JP1JP1
1
2
3
CGATE
OPT
CGATE
OPT
R7 20k R7 20k
JP2JP2
1
2
3
U1
LTC4232IDHC
U1
LTC4232IDHC
OV
3
FLT
12
UV
2
IMON 14
VDD
1
TIMER
4
INTVCC
5
ISET 15
PG 11
GATE 10
FB 13
OUT 9
GND
6
VDD
16 OUT 8
OUT 7
SENSE
17
E7
FLT
E7
FLT
RMON 20k 0805 RMON 20k 0805
R2 3.3k R2 3.3k
R6
20k
R6
20k
+
CIN1 OPT
+
CIN1 OPT
E12
INTVCC
E12
INTVCC
D4 LN1351C (GREEN) D4 LN1351C (GREEN)
2 1
D5 LN1251C (RED) D5 LN1251C (RED)
2 1
D1
SMAJ22A
D1
SMAJ22A
2 1
R5 3.3k R5 3.3k
E8
PG
E8
PG
E1
VDD
12V
E1
VDD
12V
E11
IMON
E11
IMON
R8 20k R8 20k
D3 LN1251C (RED) D3 LN1251C (RED)
2 1
R9 140k R9 140k
RGATE
OPT
RGATE
OPT
E9
TIMER
E9
TIMER
E6
OV E6 OV
E4
GND
E4
GND
E2 VOUT
12V / 5A
E2 VOUT
12V / 5A
+
COUT1 22uF 25V 7343
+
COUT1 22uF 25V 7343

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DEMO MANUAL DC1886A
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.
parts List
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
10RGATE, CGATE CAP.,0603 OPT
20 CIN1,COUT2 CAP.,SANYO\16X25\H OPT
3 1 COUT1 CAP.,TANT,22µF25V,20%,7343 AVX,TPSD226M025R0200
4 1 C1 CAP.,X5R,1µF25V,0603 AVX,06033D105KAT2A
5 1 C2 CAP.,X5R,0.1µF25V,0603 AVX,06033C104KAT2A
6 1 D1 DIODE,400WTRANSIENTVOLTAGESUPPRESSOR,SMA-DIODE DIODESINC.,SMAJ22A
72 D2, D4 LED, SMT, GREEN PANASONIC,LN1351C-(TR)
8 2 D3, D5 LED, SMT, RED PANASONIC,LN1251C-(TR)
9 4 E1, E2, E3, E4 TURRET,TESTPIN,.094" MILL-MAX,2501-2-00-80-00-00-07-0
10 8 E5-E12 TURRET,TESTPIN,.064" MILL-MAX,2308-2-00-80-00-00-07-0
11 2 JP1,JP2 JMP,HD1X3,.079CC SAMTEC,TMM-103-02-L-S
12 1 RMON RES.,CHIP,20K,1/16W,5%,0805 YAGEO,RC0805JR-0720KL
13 0RSET RES.,CHIP,0805 OPT
14 4 R1, R2, R3, R5 RES.,CHIP,3.3K,1/16W,5%,0603 YAGEO,RC0603JR-073K3L
15 1 R4 RES.,CHIP,150K,1/16W,5%,0603 YAGEO,RC0603JR-07150KL
16 3 R6,R7,R8 RES.,CHIP,20K,1/16W,5%,0603 YAGEO,RC0603JR-0720KL
17 1 R9 RES.,CHIP,140K,1/16W,5%,0603 YAGEO,RC0603JR-07140KL
18 1 R10 RES.,CHIP,226K,1/16W,5%,0603 YAGEO,RC0603JR-07226KL
19 1 U1 I.C., LTC4232IDHC, DFN16DHC LINEAR TECH., LTC4232IDHC
20 1SHUNT,0.079"CENTER SAMTEC,2SN-BK-G 325

8
dc1886af
DEMO MANUAL DC1886A
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408)432-1900 ●FAX: (408)434-0507●www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2012
LT 0312 • 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 applica-
tion engineer.
Mailing Address:
Linear Technology
1630McCarthyBlvd.
Milpitas,CA95035
Copyright©2004,LinearTechnologyCorporation