DEMO MANUAL DC116
HOT SWAP CONTROLLER
LTC1421 Hot Swap Controller
Controls Three Supplies
DESCRIPTIO
U
Demonstration circuit DC116 is a protected, triple-output
Hot SwapTM controller. This circuit is designed to allow a
PC board to be safely inserted into and removed from a live
backplane without disturbing the system power or damaging the connector pins due to high inrush currents. A
programmable electronic circuit breaker protects against
shorts.
Also included on the demo board are LEDs that indicate
whether the circuit breaker has tripped, a power failure has
occurred or the switches are turned off. A push-button
switch is provided for users to generate a system reset and
cycle the outputs. Dip switches allow the trip levels of the
output voltage monitoring circuitry to be changed.
The complete demo includes two separate boards,
DC116A and DC116B. The DC116B is used to simulate the
system backplane with three supply inputs. All the inputs
are bypassed with large capacitors. The DC116A is the
daughter board to be inserted into and removed from the
system power bus. The LTC®1421 and all other components are placed on this board. A staggered-pin connector
is used to ensure proper connection sequencing.
The applications for DC116 include any system with a data
bus and multiple power supplies that needs to be inserted
into or removed from a live system backplane.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Hot Swap is a trademark of Linear Technology Corporation.
BOARD PHOTOS
DC116A
Hot Swap Controller
DC116B
System Backplane
DC116B PHOTO
DC116A PHOTO
1
DEMO MANUAL DC116
HOT SWAP CONTROLLER
W U
WW
PERFOR A CE SU
ARY
SYMBOL
PARAMETER
CONDITIONS
VCC, VDD
Input Supply Voltage
Positive Supply
3V to 12.6V
VALUE
VEE
Input Supply Voltage
Negative Supply
– 3V to – 12.6V
ILIM
Maximum Output Current
VCC2
VDD2
10A
2A
U W
VDD2
VDD2
VCC2
VCC2
0V
0V
VEE2
VEE2
dc116 TPC01
dc116 TPC01
Figure 1. Live Insertion into the System Backplane
Figure 2. Live Removal from the System Backplane
W
PACKAGE DIAGRA
TOP VIEW
CON1
1
24 AUXVCC
CON2
2
23 VCCLO
POR
3
22 SETLO
FAULT
4
21 GATELO
DISABLE
5
20 VOUTLO
PWRGD
6
19 VCCHI
RESET
7
18 SETHI
REF
8
17 GATEHI
CPON
9
16 VOUTHI
RAMP 10
15 COMPOUT
FB 11
14 COMP –
GND 12
13 COMP +
SW PACKAGE
24-LEAD PLASTIC SO WIDE
2
5V/DIV
5V/DIV
TYPICAL PERFORMANCE CHARACTERISTICS
LTC1421CSW
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
B2
B3
B4
B5
B6
B7
B8
C1
C2
C3
C4
C5
C6
C7
C8
A2
A3
A4
A5
A6
A7
A8
AA1
AA2
AA3
AA4
AA5
AA6
AA7
AA8
MILLIPACS
HM1G41FBR000H6
B1
A1
J101
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
TP14
TP15
R18
470Ω
D6
RED
VEE1
VCC1
VCC1
RESET
TP13
R13, 470Ω
D8
AMBER
TP1
R5
16k
TP9
TP10
TP11
R20
470Ω
D5
GRN
R17
1.5k
VEE2
BOLD LINES INDICATE
HIGH CURRENT PATHS
S2
RESET
D1
RED
D4
RED
R16
1.5k
RESET
TP4
C2
0.047µF
Q2
Si4410DY
SILICONIX
+
C3
TP2 1000µF
25V
12
11
10
9
8
7
6
5
4
3
2
1
RESET
GND
FB
RAMP
CPON
REF
COMP +
COMP –
COMPOUT
VOUTHI
GATEHI
SETHI
VCCHI
VOUTLO
GATELO
SETLO
VCCLO
AUXVCC
C9, 0.1µF
PWRGD
DISABLE
FAULT
POR
CON2
REF
D3
GRN
U1
LTC1421CSW
CON1
R4
20k
R15
1.5k
D2
RED
R14
1.5k
13
14
15
16
17
18
19
20
21
22
23
24
C6
0.1µF
+
1
2
3
4
5
6
7
8
COMP +
COMP –
COMPOUT
VDD2
C1
0.1µF
C4
1000µF
25V
VDD2
S8
S1
TP3
SETHI
Q3
Si4410DY
SILICONIX
R3
0.025Ω
TP5
TP6
TP7
16
15
14
13
12
11
10
9
OUTLO
GATELO
VCC2
R23
0Ω
R22
7.5k
1%
R21
20k
1%
R6
10k
5%
SETLO
C7
0.1µF
R1
0.005Ω
C8
1µF
+
R8
2.55k
1%
R7
19.6k
1%
VDD2
D7
GRN
R19
470Ω
Q1
MTB50N06E
VCC2
R10
7.15k
1%
R9
20k
1%
DC116 SDa
TP16
TP12
R12
23.2k
1%
R11
205k
1%
VEE2
C5
2200µF
16V
TP8
SCHE ATIC DIAGRA
W
W
VDD1
DEMO MANUAL DC116
HOT SWAP CONTROLLER
DC116A
3
DEMO MANUAL DC116
HOT SWAP CONTROLLER
W
W
SCHE ATIC DIAGRA
DC116B
VEE
TP6
GROUND
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
P101
A1
B1
A2
B2
A3
B3
A4
B4
A5
B5
A6
B6
A7
B7
A8
B8
AA1
C1
AA2
C2
AA3
C3
AA4
C4
AA5
C5
AA6
C6
AA7
C7
AA8
C8
MILLIPACS
HM1V41HPR000H6
4
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
58
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
TP7
VDD
TP8
+
VCC
C2
470µF
25V
TP9
+
C1
470µF
25V
TP2
DISABLE
VCC
R1
10k
VCC
TP3
R2
10k
TP1
FAULT
POR
DATA
AUX
TP4
TP5
BOLD LINES INDICATE
HIGH CURRENT PATHS
TP10
DC116bSDb
DEMO MANUAL DC116
HOT SWAP CONTROLLER
PARTS LIST
REFERENCE
DESIGNATOR
DC116A
QUANTITY PART NUMBER
DESCRIPTION
VENDOR
TELEPHONE
C1, C6, C7, C9
4
12065C104KAT2
0.1µF 50V 10% X7R Capacitor
AVX
(803) 946-0362
C2
1
12065C473KAT2
0.047µF 50V 10% X7R Capacitor
AVX
(803) 946-0362
C3, C4
2
25MV102CZ
1000µF 25V Aluminum Capacitor
Sanyo
(619) 661-6835
C5
1
16MV222CZ
2200µF 16V Aluminum Capacitor
Sanyo
(619) 661-6835
C8
1
6Y5U105Z025AL
1µF 25V 10% Y5U Capacitor
Murata
(814) 237-1431
D1, D2, D4, D6
4
5600F1
Red LED
Chicago Miniature Lamp
(201) 489-8989
D3, D5, D7
3
5600F5
Green LED
Chicago Miniature Lamp
(201) 489-8989
D8
1
5600F7
Yellow LED
Chicago Miniature Lamp
(201) 489-8989
J101
1
HM1G41FBR000H6
Millipacs Female Connector
FCI
(717) 767-8005
Q1
1
MTB50N06E
N-Channel MOSFET, 50A, 60V
Motorola
(602) 244-3576
Q2, Q3
1
Si4410DY
N-Channel MOSFET
Siliconix
(800) 554-5565
R1
1
WSL-2010-005-1%
0.005Ω 1/2W 1% Resistor
Dale
(605) 665-9301
R3
1
WSL-2010-025-1%
0.025Ω 1/2W 1% Resistor
Dale
(605) 665-9301
R4
1
CR32-203J-T
20k 1/8W 5% Resistor
AVX
(803) 946-0524
R5
1
CR32-163J-T
16k 1/8W 5% Resistor
AVX
(803) 946-0524
R6
1
CR32-103J-T
10k 1/8W 5% Resistor
AVX
(803) 946-0524
R7
1
CR32-1962F-T
19.6k 1/8W 1% Resistor
AVX
(803) 946-0524
R8
1
CR32-2491F-T
2.49k 1/8W 1% Resistor
AVX
(803) 946-0524
R9, R21
2
CR32-2002F-T
20k 1/8W 1% Resistor
AVX
(803) 946-0524
R10
1
CR32-7151F-T
7.15k 1/8W 1% Resistor
AVX
(803) 946-0524
R11
1
CR32-2053F-T
205k 1/8W 1% Resistor
AVX
(803) 946-0524
R12
1
CR32-2322F-T
23.2k 1/8W 1% Resistor
AVX
(803) 946-0524
R13, R18 to R20
4
CR32-470J-T
470Ω 1/8W 5% Resistor
AVX
(803) 946-0524
R14 to R17
4
CR32-152J-T
1.5k 1/8W 5% Resistor
AVX
(803) 946-0524
R22
1
CR32-7501F-T
7.5k 1/8W 1% Resistor
AVX
(803) 946-0524
R23
1
CJ-000T
0Ω 1/8W 5% 1206 Resistor
AVX
(803) 946-0524
S1
1
DMR-08
Switch
APEM
(781) 246-1007
S2
1
MJTP1236
Switch
APEM
(781) 246-1007
TP1, TP4 to TP7, TP9 to
TP11, TP13 to TP16
12
1502-2
Turret
Keystone
(718) 956-8900
TP2, TP3, TP8, TP12
4
575-4
Banana Jack
Keystone
(718) 956-8900
U1
1
LTC1421CSW
IC
Linear Technology
(408) 432-1900
1
Demo Board DC116A
Printed Circuit Board
DC116B
C1, C2
2
25MV470CZ
470µF 25V Elect Capacitor
Sanyo
(619) 661-6835
P101
1
HM1V41HPR000H6
Millipacs Male Connector
FCI
(717) 767-8005
R1, R2, R3
2
CR32-103J-T
10k 1/8W 5% Resistor
AVX
(803) 946-0524
TP1 to TP5, TP10
6
1502-2
Turret
Keystone
(718) 956-8900
TP6 to TP9
4
575-4
Banana Jack
Keystone
(718) 956-8900
#4-40x1/4” Screw HWD
Any
#4-40x1/2” Stand-Off Nylon Hex HWD
Keystone
4
4
1
Demo Board DC116B
(718) 956-8900
Printed Circuit Board
5
DEMO MANUAL DC116
HOT SWAP CONTROLLER
QUICK START GUIDE
The demonstration board set, DC116, is easily set up for
evaluation of the LTC1421 IC. Please follow the procedure outlined below for error-free operation.
• Connect the loads to outputs VCC2 (TP8), VDD2 (TP3)
and VEE2 (TP2) on the DC116A board. Connect the
return side of the lead(s) to TP12 or TP16 (GND).
• Connect the positive power supply with the lower
potential to VCC (TP9) and the higher one to VDD (TP8)
on DC116B. Connect the ground lead(s) to TP6. Do
not exceed 12.6V for either supply to ensure proper
operation of the LTC1421.
• Select the proper dip switches to monitor the outputs
and set the trip level for the RESET output.
• Connect the negative power supply to VEE (TP7)
and GND (TP6) on DC116B. Do not exceed –12.6V
on VEE.
• Apply power and insert the daughter board (DC116A)
into the system backplane (DC116B). Rock the daughter board back and forth to ensure good connection.
• The LEDs will turn on to indicate the status of the input
and output supplies as well as the circuit breaker.
U
OPERATIO
The circuit shown in the Schematic Diagram allows three
power supplies, VDD, VCC and VEE, to be safely inserted
into and removed from the backplane. VCC and VDD are
both positive supplies, whereas VEE is a negative supply.
The main supply to the LTC1421 is from VCC; its voltage
should be less than or equal to that of VDD. The nominal
voltages are 5V for VCC, 12V for VDD and –12V for VEE.
A 0.005Ω sense resistor (R1) sets the current limit to 10A
at the VCC output; R3 (0.025Ω) sets the current limit at VDD
to 2A. The LTC1421 monitors the voltage across the sense
resistors. When either voltage is greater than 50mV, the
internal charge pump is turned off immediately and both
the gates and voltage outputs are actively pulled to ground.
The circuit breaker function remains active until the pushbutton switch (S2) is pressed and released or the power is
cycled.
The LTC1421 limits the inrush current through the
N-channel pass transistor by increasing the voltage on the
gate in a controlled manner. The transient surge current
(I = COUT • dVOUT/dt) drawn from the main backplane
power supply can then be limited to a safe value. The ramp
slope is determined by a fixed internal current source
(20µA) and a ramp capacitor (C9) connected between the
RAMP and GATEHI pins. The voltage at GATEHI rises with
6
a slope equal to 20µA/CRAMP. The voltage at the GATELO
pin is clamped one Schottky diode drop below GATEHI.
The negative supply voltage can be controlled using the
CPON pin. When the board makes a connection, the
N-channel pass transistor, Q2, is turned off by R4. CPON
is also pulled down to VEE1. When the charge pump is
turned on, CPON is pulled to VCC1 and the gate of Q2 ramps
up with a time constant determined by R4, R5 and C2.
When the charge pump is turned off, CPON goes into high
impedance state; the gate of Q2 is then discharged to VEE1
with a time constant determined by R4 and C2 and then Q2
turns off. There is no circuit breaker or current-limit
feature on the negative supply.
Power N-Channel MOSFET
External N-channel pass transistors are used to route the
power from the system power supply to the plug-in board.
An MTB50N06E from Motorola is used for the VCC output
and two 8-lead, surface mounted NFETs from Siliconix
(Si4410DY) are used for VDD and VEE. A number of similar
N-channel MOSFETs, available from different manufacturers, are also well-suited for this type of application. As a
general rule, select the MOSFET with the lowest RDS(ON) to
get the smallest voltage drop across it at the maximum
output load.
DEMO MANUAL DC116
HOT SWAP CONTROLLER
U
OPERATIO
LEDs
Several LEDs are included on the demo board to indicate
the status of the input and output voltages and the circuit
breaker. D2, D4 and D6, when turned on, indicate that the
input supplies (VDD1, VEE1 and VCC1) from the connector
are ready. The green LEDs (D3, D5 and D7), when turned
on, indicate that the pass transistors are on and the input
supplies have been routed to the outputs. D8 is connected
from the RESET pin to VCC1 through a 470Ω resistor. D8
turns on immediately after the board is inserted into the
system power supplies and turns off 200ms after the
PWRGD pin goes high. When the red LED (D1) lights up,
a general fault condition has occurred: either the circuit
breaker has tripped, a power failure has occurred or the
gate driver is turned off.
Dip Switches (S1 to S8)
Eight dip switches on the demo board provide users with
a convenient way to configure the output voltage(s) to be
monitored and the trip levels for the RESET output. Five
different configurations are listed below:
U
W
PCB LAYOUT A D FIL
1. Close S3, S5 and S8: monitor VDD2 at 10.8V; reset VCC2
at 4.65V.
2. Close S1, S3, S6 and S8: monitor VCC2 at 4.65V; reset
VCC2 at 2.9V.
3. Close S4, S5 and S8: reset VDD2 at 10.8V; reset VCC2 at
4.65V.
4. Close S2, S3, S4 and S8: reset VCC2 at 4.5V.
5. Close S3 and S7: monitor VEE2 at – 10.8V; reset VCC2 at
4.65V.
Connector
A staggered-pin connector (HM1V41HPR000H6) from
FCI is used on the boards for hot swapping. The ground
pins are the longest, making connection first and breaking
connection last. This will prevent ESD damage on the rest
of the pins when a huge ground potential difference exists
between the two boards. The connect pins (CON1 and
CON2) are shortest, and are placed on the opposite end of
the connector. The LTC1421 will not start turning on the
pass transistors until the whole connector is plugged in
and both CON1 and CON2 are connected.
DC116A
DC116A ASY
Assembly Top
DC116A SLK
Silkscreen Top
7
DEMO MANUAL DC116
HOT SWAP CONTROLLER
U
W
PCB LAYOUT A D FIL
DC116A
DC116A SLD
DC116A COMP
Solder Side
Component Side
DC116A SMT
DC116A PMT
Paste Mask Top
Solder Mask Top
DC116A SLDB
Solder Mask Bottom
8
DEMO MANUAL DC116
HOT SWAP CONTROLLER
U
W
PCB LAYOUT A D FIL
DC116B
DC116B SLK
Silkscreen Top
DC116B ASY
Assembly Top
DC116B COMP
Component Side
DC116B SLD
Solder Side
9
DEMO MANUAL DC116
HOT SWAP CONTROLLER
U
W
PCB LAYOUT A D FIL
DC116B
DC116B SLDT
DC116B PMT
Paste Mask Top
Solder Mask Top
DC116B SLDB
Solder Mask Bottom
10
DEMO MANUAL DC116
HOT SWAP CONTROLLER
U
PC FAB DRAWI G
DC116A
3.975
A
D
C
D
G
A
A
H
H
H
2.600
D
C
D
D
C
D
D
C
D
G
H
H
H
H
H
H
A
G
G
G
G
G
G
F
H
F
H
H
H
H
H
B
B
B
B
B
B
B
B
E
F
E
F
F
H
H
H
B
F
H
B
B
B
F
NUMBER
SYMBOL DIAMETER OF HOLES PLATED
A
0.205
4
YES
B
0.094
12
YES
C
0.081
4
NO
D
0.060
8
NO
E
0.045
2
YES
F
0.035
18
YES
G
0.025
102
YES
H
0.015
39
YES
TOTAL HOLES 189
NOTES: UNLESS OTHERWISE SPECIFIED
1. MATERIAL: 2 LAYERS, 0.062" THICK FR-4 GLASS EPOXY 2 OZ COPPER CLAD
2. ALL DIMENSIONS ARE IN INCHES ±0.003
3. PLATE THRU HOLES WITH COPPER 0.0014 MIN THICKNESS.
ALL HOLE SIZES IN HOLE TABLE ARE AFTER PLATING
4. SILSCREEN: WITH WHITE EPOXY NONCONDUCTIVE INK
5. FINISH: SMOBC
6. SOLDER MASK: LPI, GREEN
DC116A FAB
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 representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
11
DEMO MANUAL DC116
HOT SWAP CONTROLLER
U
PC FAB DRAWI G
DC116B
3.500
3.300
B
E
A
B
D
C
D
A
E
F
C
2.400
D
A
C
D
D
F
C
C
D
C
0.200
A
D
B
B
0.200
NUMBER
SYMBOL DIAMETER OF HOLES PLATED
A
0.205
4
YES
B
0.125
4
YES
C
0.094
6
YES
D
0.060
8
NO
E
0.030
96
YES
F
0.025
4
YES
TOTAL HOLES 122
NOTES: UNLESS OTHERWISE SPECIFIED
1. MATERIAL: 2 LAYERS, 0.062" THICK FR-4 GLASS EPOXY 2 OZ COPPER CLAD
2. ALL DIMENSIONS ARE IN INCHES ±0.003
3. PLATE THRU HOLES WITH COPPER 0.0014 MIN THICKNESS.
ALL HOLE SIZES IN HOLE TABLE ARE AFTER PLATING
4. SILSCREEN: WITH WHITE EPOXY NONCONDUCTIVE INK
5. FINISH: SMOBC
6. SOLDER MASK: LPI, GREEN
DC116B FAB
12
Linear Technology Corporation
dc116 LT/TP 0898 500 • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408)432-1900 ● FAX: (408) 434-0507 ● www.linear-tech.com
 LINEAR TECHNOLOGY CORPORATION 1998