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DEMO MANUAL DC1625A
Description
LTC4227-1/LTC4227-2/
LTC4227-3/LTC4227-4
Dual Ideal Diode and
Single Hot Swap Controller
Demonstration circuit 1625A is intended to demonstrate
performance of the LTC4227-1/LTC4227-2/LTC4227-3/
LTC4227-4 dual ideal diode and Hot Swap™ controller. Each
rail has an individual ideal diode. Ideal diode outputs are
connected to the load through a single Hot Swap circuit.
The DC1625 allows verifying the LTC4227 Hot Swap and
ideal diode functionality during individual supply ramp-up
and ramp-down transients, during power supply switch-
over, steady state, and overcurrent fault conditions.
Each DC1625A rail circuit is assembled to operate over
the full operating voltage range of the LTC4227: 2.9V to
18V, with a 7.6A maximum current load.
The board’s main components include the LTC4227 con-
troller, two power MOSFETs controlled as ideal diodes and
one power MOSFET controlled as a Hot Swap device, two 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.
perForMAnce sUMMArY
jumpers for enabling the second ideal diode (D2ON_SEL)
and Hot Swap controller (HS_ON), two LEDs to indicate
power good (PWRGD) and fault (FAULT) conditions, seven
banana jacks for connecting power supplies and load, many
turrets and pads for observing circuit signals.
Table 1. DC1625A Assembly Options
VERSION PART
OVERCURRENT
FAULT
START-UP
DELAY
DC1625A-A LTC4227-1 LATCHOFF 100ms
DC1625A-B LTC4227-2 RETRY 100ms
DC1625A-C LTC4227-3 LATCHOFF 1.6ms
DC1625A-D LTC4227-4 RETRY 1.6ms
Design files for this circuit board are available at
http://www.linear.com/demo
(TA = 25°C)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Supplies
VIN Input Supply Range 2.9 18.0 V
VINTVCC Internal Regulator Voltage 4.5 55.6 V
VINTVCC(UVL) Internal VCC Undervoltage Lockout INTVCC Rasing 2.1 2.2 2.3 V
Ideal Diode Control
ΔVFWD(REG) Forward Regulation Voltage (VINn – VSENSE)10 25 40 mV
ΔVDGATE External N-Channel Gate Drive
(VDGATEn - VINn)
IN < 7V, ΔVFWD = 0.1V
IN = 7V to 18V, ΔVFWD = 0.1V
5
10
7
12
14
14
V
V
ICPO(UP) CPOn Pull-Up Current CPO = IN = 2.9V
CPO = IN = 18V
–60
–50
–95
–85
–120
–110
µA
µA
IDGATE(FPU) DGATEn Fast Pull-Up Current ΔVFWD = 0.2V, ΔVDGATE = 0V, CPO = 17V –1.5 A
IDGATE(FPD) DGATEn Fast Pull-Down Current ΔVFWD = –0.2V, ΔVDGATE = 5V 1.5 A
IDGATE2(DN) DGATE2 Off Pull-Down Current D2ON = 2V, ΔVDGATE2 = 2.5V 40 100 200 µA
tON(DGATE) DGATEn Turn-On Delay ΔVFWD = 0.2V, CGATE = 10nF 0.25 0.5 µs
tOFF(DGATE) DGATEn Turn-Off Delay ΔVFWD = –0.2V, CGATE = 10nF 0.2 0.5 µs
tPLH(DGATE2) D2ON Low to DGATE2 High 40 100 µs
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DEMO MANUAL DC1625A
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Hot Swap Control
ΔVSENSE(CB) Circuit Breaker Trip Sense Voltage
(VSENSE+ - VSENSE–)
47.5 50 52.5 mV
ΔVSENSE(ACL) Active Current Limit Sense Voltage
(VSENSE+ - VSENSE–)
60 65 70 mV
ΔVHGATE External N-Channel Gate Drive (VHGATE - VOUT) IN < 7V, I = 0, –1μA
IN = 7V to 18V, I = 0, –1μA
4.8
10
7
12
14
14
V
V
IGATE(UP) External N-Channel Gate Pull-Up Current Gate Drive On, HGATE = 0V –7 –10 –13 µA
IHGATE(DN) External N-Channel Gate Pull-Down Current Gate Drive Off, OUT = 12V, HGATE = OUT + 5V 150 300 500 µA
IHGATE(FPD) External N-Channel Gate Fast Pull-Down
Current
Fast Turn-Off, OUT = 12V, HGATE = OUT + 5V 100 200 300 mA
Input/Output Pin
VSENSE+(UVL) SENSE+ Undervoltage Lockout SENSE+ Rising 1.75 1.9 2.05 V
VON(TH) ON Pin Threshold Voltage ON Rising 1.21 1.235 1.26 V
VON(RESET) ON Pin Fault Reset Threshold Voltage ON Falling 0.55 0.6 0.65 V
VD2ON(TH) D2ON Pin Threshold Voltage D2ON Rising 1.21 1.235 1.26 V
VTMR(TH) TMR Pin Threshold Voltage TMR Rising
TMR Falling
1.198
0.15
1.235
0.2
1.272
0.25
V
V
ITMR(UP) TMR Pull-Up Current TMR = 1V, In Fault Mode –75 –100 –125 µA
ITMR(DN) TMR Pull-Down Current TMR = 2V, No Faults 1.4 22.6 µA
ITMR(RATIO) TMR Current Ratio ITMR(DN)/ ITMR(UP) 1.4 22.7 %
perForMAnce sUMMArY
operAting principles
The LTC4227 is intended to build a combination of two
diode-OR circuits (for two rails) and a common single
Hot Swap path for inrush current limiting and overcurrent
protection.
The LTC4227 regulates the forward voltage drop across
the MOSFETs to ensure smooth current transfer from one
supply to other without oscillation. A fast turn-on reduces
the load voltage droop during supply switchover. If the
input supply fails or is shorted, a fast turn-off minimizes
reverse current transients.
The Hot Swap fast acting current limit and internal timed
circuit breaker protect circuit components when a short-
circuit fault occurs.
The Hot Swap function on the LTC4227 controller has
independent on/off control.
Each ideal diode MOSFET is activated from individual
charge pump sources and the second ideal diode path
has additional on/off control.
The LTC4227-1 and LTC4227-3 feature a latchoff circuit
breaker, while the LTC4227-2 and the LTC4227-4 provide
automatic retry after a fault.
(TA = 25°C)
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DEMO MANUAL DC1625A
qUick stArt proceDUre
Demonstration circuit 1625A is easy to set up to evalu-
ate the performance of the LTC4227. Refer to Figure 1
for proper measurement equipment setup and follow the
procedure below:
The DC1625A test includes independent test of the LTC4227
hot swapping functionality and ideal diode functionality.
HOT SWAP FUNCTIONALITY TEST
This test is performed with singe rail operation, when
the rail output is provided through two series connected
MOSFETs. One MOSFET functions as an ideal diode and
other one as a Hot Swap circuit component.
The parameters of the three transients in different opera-
tion modes completely characterize the Hot Swap circuit
performance. These actions are:
- A power-up without any additional load
- A current limit operation after successful power-up
transient
- A power-up with shorted output
1. Initially, install the jumper heads in the following posi-
tions, if the first ideal diode is used in the test:
JP1 EN_SEL in the position LOW
JP2 D2ON_SEL in the position OFF
JP3 ON_SEL in the position OFF
If the second ideal diode is used:
JP1 EN_SEL in the position LOW
JP2 D2ON_SEL in the position ON
JP3 ON_SEL in the position OFF
Connect a 12V power supply to the board input turrets
IN1 (or IN2) and GND. Do not load the output. Place
the current probe on the 12V wire and voltage probes
on the OUT turret.
Provide ON signal at the ON pin by changing the JP3
jumper header position from OFF position to ON. Observe
the transient. The output voltage rise time should be
in the range of 12ms to 29ms. PWRGD green LED D3
(D5) must turn on. Turn off the rail using the ON jumper.
2. Connect a disabled electronic load to the OUT turret
and GND. Turn on the rail and slowly increase the load
current up to the circuit breaker threshold level. The
current limit range should be from 7.8A to 8.9A.
The DC1625A-A and DC1625-C circuit feature a latchoff
circuit breaker, and DC1625A-B and the DC1625-D
provide automatic retry after a fault.
Turn off the rail with the ON_SEL jumper.
3. Initially short output with external wire. Place the current
probe at this external wire. Turn on the rail and record
the current shape. The maximum current should be in
the 10.1A to 11.8A range.
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DEMO MANUAL DC1625A
IDEAL DIODE FUNCTIONALITY TEST
In this test, both ideal diodes are active and small varia-
tions in the input voltage forces one ideal diode to be off
and another ideal diode to be on.
Connect input turrets (IN1 and IN2) of each ideal diode
with individual independent lab supply. Adjust each input
voltage to 12V with maximum possible accuracy. Place
qUick stArt proceDUre
one voltmeter between IN1 and IN2 turrets to measure
the difference between two input voltages. Connect an
electronic load to the output turret. Activate both rail and
keep a load around 1A to 3A. Play with input voltage levels
and be sure that when the difference between input volt-
ages exceeds 40mV, only one rail feeds the load.
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DEMO MANUAL DC1625A
qUick stArt proceDUre
Figure 1. DC1625A Measurement Equipment Setup
SWITCH
DC1625A F01
POWER
SUPPLY 1
POWER
SUPPLY 2
LOAD
–
+
–
+
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DEMO MANUAL DC1625A
pArts list
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
DC1625A General BOM
1 8 C1, C2 ,C3, C4, C6,
C7, C10, C11
CAP, X7R, 0.1µF, 50V, 0603 TDK, C1608X7R1H104K
2 1 C5 CAP, X7R, 15nF, 50V, 0603 AVX, 06035C153KAT
3 0 C8, C9 OPT CAP, AL, El, S/M 100µF, 50V SUNCON, 50CE100BS
4 1 C12 CAP, AL, El, S/M 100µF, 50V SUNCON, 50CE100BS
5 0 C12 OPT CAP, AL, El, S/M 1000µF, 50V NIC, NACEW102M50V16X17TR13F
6 2 D1, D2 DIODE, VOLTAGE SUPPRESSOR, SMA DIODES, SMAJ17A-13-F
7 1 D3 LED, SMT GREEN PANASONIC, LN1351CTR
8 1 D4 LED, SMT RED PANASONIC, LN1261CTR
911 E1, E3, E6, E8, E9,
E12 to E17
TURRET, TESTPOINT, 2501 MILL-MAX, 2501-2-00-80-00-00-07-0
10 7 E2, E4, E5, E7, E10,
E11, E18
JACK BANANA KEYSTONE, 575-4
11 2E27, E28 TURRET, TESTPOINT, 2308 MILL-MAX, 2308-2-00-80-00-00-07-0
12 3JP1, JP2, JP3 HEADERS, 3 PINS 2mm CTRS SAMTEC TMM-103-02-L-S
13 3XJP1, XJP2, XJP3 SHUNT, 2mm CTRS SAMTEC 2SN-BK-G
14 2Q1, Q2 MOSFET, N-CHANNEL, 30V VISHAY, SiR462DP-T1-GE3
15 1 Q3 MOSFET, N-CHANNEL, 30V VISHAY, Si7336ADP-T1-GE3
16 1 RS1 RES, CHIP, 0.006, 1/2W, 1%, 2010 KOA, TLR2HDBK6L00F75
17 3 R1, R9, R10 RES, CHIP, 10, 1%, 0603 VISHAY, CRCW060310R0FKEA
18 1 R2 RES, CHIP, 47, 1%, 0603 VISHAY, CRCW060347R0FKEA
19 2 R3, R7 RES, CHIP, 20k, 1%, 0603 VISHAY, CRCW060320K0FKEA
20 1R4 RES, CHIP, 22.1k, 1%, 0603 VISHAY, CRCW060322K1FKEA
21 2 R5, R6 RES, CHIP, 3k, 1%, 0805 VISHAY, CRCW08053K00FKEA
22 1R8 RES, CHIP, 28.7k, 1%, 0603 VISHAY, CRCW060328K7FKEA
23 4STAND-OFF STAND-OFF, NYLON 0.5" KEYSTONE, 8833 (SNAP ON)
24 1STENCIL STENCIL 1625A
DC1625A-A
1 1 DC1625A General BOM
2 1 U1 I.C. LTC4227CUFD-1, QFN20-4x5 LINEAR TECHNOLOGY, LTC4227CUFD-1
DC1625A-B
1 1 DC1625A General BOM
2 1 U1 I.C. LTC4227CUFD-2, QFN20-4x5 LINEAR TECHNOLOGY, LTC4227CUFD-2
DC1625A-C
1 1 DC1625A General BOM
2 1 U1 I.C. LTC4227CUFD-3, QFN20-4x5 LINEAR TECHNOLOGY, LTC4227CUFD-3
DC1625A-D
1 1 DC1625A General BOM
2 1 U1 I.C. LTC4227CUFD-4, QFN20-4x5 LINEAR TECHNOLOGY, LTC4227CUFD-4
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DEMO MANUAL DC1625A
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
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D D
C C
B B
A A
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ASSY TABLE
(
TECHNOLOGY
TECHNOLOGY
TECHNOLOGY
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2
1
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DEMO MANUAL DC1625A
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 1013 REV A • 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
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