DEMO MANUAL DC1051A
LTC4217
2A Integrated
Hot Swap Controller
Description
Demonstration circuit 1051A includes two separate circuits
for performance evaluation of the LTC
®
4217 2A integrated
Hot Swap™ controller. This integrated circuit includes
a power MOSFET to save board area and to minimize
external component count. The standard version of the
controller (LTC4217) is intended to operate with 2.9V to
26.5V rails, while the LTC4217-12 has internal adjustment
for 12V applications.
The circuit of DC1051A located on the upper board area
is assembled with the LTC4217 configured for operation
with a 24V rail. The lower circuit includes the LTC4217-12.
Current limit features of both circuits are identical, with
5% accuracy and a distinctive foldback property.
The LTC4217 features a ground-referred current monitor.
The current monitor sources a current that is proportional
to the sense voltage and it may be converted to a voltage
signal with an appropriate resistor.
The current limit may be reduced by placing an external
resistor between GND and the ISET pin.
The DC1051A schematic allows the LTC4217 to operate in
turn-on and turn-off modes as well as in the steady-state
mode with different loads, and in the fault mode.
The LTC4217 features an overtemperature protection
circuit, and protects the load from overvoltage and un-
dervoltage conditions.
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.
performance summary
SYMBOL
24V Circuit
V
DD
V
DD(UVL)
V
DD(OVH)
t
TIMER
I
LIM
C
MAX24
C
MIN24
12V Circuit
V
DD
V
DD(UVL)
V
DD(OVH)
t
TIMER
I
LIM
C
MAX12
C
MIN12
Input Supply Range
Input Supply Undervoltage Range
Input Supply Overvoltage Range
Timer Period
Current Limit Value
Maximal Load Capacitance
Minimal Load Capacitance
Input Supply Range
Input Supply Undervoltage Range
Input Supply Overvoltage Range
Timer Period
Current Limit Value
Maximal Load Capacitance
Minimal Load Capacitance
PARAMETER
Specifications are at T
A
= 25°C
MIN
19.9
19.12
25.32
0.9
1.9
0.35
TYP
24
19.9
26.3
1.235
2
0.5
900
3500
9.88
9.6
14.7
0.9
1.9
0.35
12
9.88
15.05
1.235
2
0.5
1000
4000
15.05
10.2
15.4
1.76
2.1
0.7
MAX
26.3
20.30
27.38
1.76
2.1
0.7
UNITS
V
V
V
ms
A
A
µF
µF
V
V
V
ms
A
A
µF
µF
dc1051af
CONDITIONS
Typical Value
V
DD
Rising
V
DD
Rising
V
FB
= 1.235V (V
OUT
in the Range 20.3V to 21.2V)
V
FB
= 0V to 0.15V (V
OUT
in the Range 0V to 2.5V)
For Successful Power-Up
For Unsuccessful Power-Up
Typical Value
V
DD
Rising
V
DD
Rising
V
TIMER
Rising
V
FB
= 1.235V (V
OUT
in the Range 10.15V to 10.6V)
V
FB
= 0V to 0.15V (V
OUT
in the Range 0V to 1.15V)
For Successful Power-Up
For Unsuccessful Power-Up
1
DEMO MANUAL DC1051A
operating principles
The LTC4217 is suited for low voltage applications such as
hot board insertion and removal. The LTC4217 has a rich
set of features to support Hot Swap applications including:
• Integrated power MOSFET for a compact Hot Swap
solution
• 2% accurate undervoltage and overvoltage protection
• Adjustable 5% accurate current limit
• Adjustable inrush current control
• Load current monitoring
• Adjustable current limit timer before power is turned
off
• Power good signaling
Quick start proceDure
Demonstration circuit 1051 is easy to set up to evaluate
the performance of the LTC4217. Refer to Figure 1 for
the proper measurement equipment setup and follow the
procedure below.
For the 24V circuit:
1. Place jumpers in the following positions:
JP1
FAULT
JP2
AUX_UV
Signal
ON
6. Use a 900μF capacitive load to demonstrate that power
up mode completes successfully. Use a current probe
to verify that inrush current is limited initially by the
foldback characteristic and later by the low output
voltage slew rate.
7. Use a 3500μF capacitive load to demonstrate that the
part not only enters into the current limit state but
operates in this state until the timer period expires.
For the 12V circuit:
8. Place jumpers in the following positions:
JP3
JP4
FAULT
AUX_UV
Signal
ON
2. With power off, connect the 24V power supply terminals
to the 24V
IN
(E1) and GND (E3) turrets.
3. Turn on the 24V supply and verify the output voltage
between the V
OUT
(E7) and GND (E8) turrets. Two green
LEDs, 24V
IN
(D2) and V
OUT
(D6), should light up.
4. Check the current limit using an electronic or resistive
load. It should be in the range of 1.9A to 2.1A if an
overcurrent condition occurs while the output is high
(after powering up properly). If the output is shorted
initially, the load current will be limited in the range of
0.475A to 0.525A due to the foldback characteristic.
Current may be monitored on the IMON test point
during this measurement. The IMON signal scale is
1V/A.
An overcurrent condition is indicated by red LED
FAULT
(D3) and red LED PG (D4).
5. Check the output voltage slew rate with an oscilloscope,
without a load connected. It takes 43.6ms to 160ms
for the output voltage to power up completely.
9. With power off, connect the 12V power supply terminals
to the 12V
IN
(E9) and GND (E12) turrets.
10. Turn on the 12V supply and verify the output voltage
at the V
OUT
(E15) and GND (E16) turrets. Green LEDs
12V
IN
(D8) and V
OUT
(D12) should light.
11. Check the current limit using an electronic or resis-
tive load. It should be in the range of 1.9A to 2.1A.
During this measurement verify the current monitor
performance. The monitor signal related to the current
limit level should be 1.9V to 2.1V.
12. Check the output voltage slew rate with an oscilloscope,
without a load connected. It should take from 21ms
to 80ms for the output voltage to rise to 12V.
dc1051af
2
DEMO MANUAL DC1051A
Quick start proceDure
13. Use a 1000μF capacitive load to demonstrate that the
part powers up without fault. Use a current probe to
observe that inrush current is limited by the low output
voltage slew rate.
14. Use a 4000μF capacitive load to demonstrate that the
part enters the current limit state, and operates in this
state until the timer period expires. The
FAULT
red LED
(D9) indicates this state accompanied by the PG red
LED, which shows that the output voltage is lower than
the power good level.
Figure 1. Measurement Equipment Setup
dc1051af
3
DEMO MANUAL DC1051A
parts list
ITEM
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
QTY
3
0
8
8
4
4
4
4
1
1
1
4
4
2
2
1
1
0
1
1
REFERENCE
C2, C3, C5
C1, C4, CIN1, CIN2, COUT1, COUT2
E2, E4, E5, E6, E10, E11, E13, E14
E1, E3, E7, E8, E9, E12, E15, E16
JP1 - JP4
JP1 - JP4
D3, D4, D9, D10
D2, D6, D8, D12
D1
D7
R6
R11, R13, R14, R15
R1, R3, R4, R8
R7, R10
RMON1, RMON2
R9
R5
RSET1, RSET2, R2, R12
U1
U2
PART DESCRIPTION
CAP., CER X7R 0.1µF 16V 0603
OPTIONAL
TURRET, TEST PIN, .061"
TURRET, TEST PIN, .095"
JUMPER, 0.079, 3PIN
SHUNT
LED, SMT RED
LED, SMT GREEN
DIODE, 400W TRANSIENT VOLTAGE
SUPPRESSOR
DIODE, 400W TRANSIENT VOLTAGE
SUPPRESSOR
RES., CHIP, 3.24k 1/16W 1% 0603
RES., CHIP, 3.30k 1/16W 5% 0603
RES., CHIP, 6.80k 1/4W 5% 1206
RES., CHIP, 10k 1/16W 1% 0603
RES., CHIP, 20k 1/16W 5% 0805
RES., CHIP, 158k 1/16W 1% 0603
RES., CHIP, 200k 1/16W 1% 0603
OPTIONAL
IC., HOT SWAP CONTROLLER
IC., HOT SWAP CONTROLLER
MILL-MAX 2308-2-00-44
MILL-MAX 2501-2
SAMTEC, TMM-103-02-L-S
SAMTEC, 2SN-BK-G
PANASONIC, LN1251C
PANASONIC, LN1351C
DIODES INC., SMAJ24A
DIODES INC., SMAJ12A
VISHAY, CRCW06033K24FKTA
VISHAY, CRCW06033K30JEA
VISHAY, CRCW12066K80JNEA
VISHAY, CRCW060310K0FEA
VISHAY, CRCW080520K0JEA
VISHAY, CRCW0603158KFEA
VISHAY, CRCW06032003F
OPT
LINEAR, LTC4217CFE
LINEAR, LTC4217CDHC-12
MANUFACTURER/PART NUMBER
AVX 0603YC104KAT2A
dc1051af
4
1
2
3
4
5
6
7
8
24VIN
R2
(Opt.)
1
C1
(Opt.)
1
SENSE
SENSE
VDD
2
2
ISET
IMON
FB
FAULT
PG
JP2
GATE
OUT
SENSE
11
E5
12
13
14
15
3
2
1
Signal
Auto-Retry
E4
16
RMON1
20K
1%
FAULT
17
18
E2
19
RSET1
(Opt.)
VDD
UV
OV
TIMER
INTVCC
GND
OUT
OUT
SENSE
2
3
C2
0.1uF
16V
4
5
6
7
8
9
10
20
1
R5
200K
1%
U1
LTC4217CFE
R3
6.8K
1206
R4
6.8K
1206
E1
R1
6.8K
1206
+
CIN1
(Opt.)
1
D1
SMAJ24A
D3
LED
(RED)
FAULT
D4
LED
(RED)
PG
1
A
D2
LED
(GRN)
2
FAULT SIGNAL
A
2
GND
1
2
3
JP1
R7
10K
1%
C3
0.1uF
16V
AUX_UV
R6
3.24K
1%
E3
ON
OFF
PG
schematic Diagram
IMON
E6
ISET
B
B
D6
LED
(GRN)
R8
6.8K
1206
1
R10
10K
1%
E8
R9
158K
1%
2
E7
VOUT
24V/2A
C6
2.2uF
35V
GND
12VIN
R12
(Opt.)
1
C4
(Opt.)
1
VDD
2
UV
OV
TIMER
INTVCC
GND
OUT
OUT
OUT
9
GATE
10
PG
11
FAULT
12
FB
13
3
2
1
JP3
RMON2
20K
1%
IMON
14
FAULT
Signal
Auto-Retry
ISET
15
VDD
2
3
4
C5
0.1uF
16V
5
6
7
8
16
RSET2
(Opt.)
U2
LTC4217CDHC
1
R13
3.3K
R14
3.3K
E9
R11
3.3K
+
CIN2
(Opt.)
1
C
1
D7
SMAJ12A
D9
LED
(RED)
FAULT
D8
LED
(GRN)
E10
FAULT SIGNAL
D10
LED
(RED)
PG
2
C
2
2
GND
E12
E11
PG
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.
E13
IMON
E14
LTC CONFIDENTIAL - FOR CUSTOMER USE ONLY
E15
R15
3.3K
1
ISET
D
C7
2.2uF
35V
2
D12
LED
(GRN)
VOUT
12V/2A
Customer Notice
LINEAR TECHNOLOGY CORPORATION
1630 McCARTHY BLVD.
MILPITAS, CA. 95035
PHONE (408) 954-8400 FAX (408) 434-0507
Title
D
Positive 24V, Positive 12V Integrated Hot Swap
E16
GND
4
1
2
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
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.
5
6
Size
Date:
Document Number
Demo Circuit 1051A
Wednesday, February 15, 2006
7
Rev
Sheet
1
of
1
8
DEMO MANUAL DC1051A
dc1051af
5
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