LTC1421CSW#TR Linear Technology, LTC1421CSW#TR Datasheet

IC CONTROLLER HOTSWAP ADJ 24SOIC

LTC1421CSW#TR

Manufacturer Part Number
LTC1421CSW#TR
Description
IC CONTROLLER HOTSWAP ADJ 24SOIC
Manufacturer
Linear Technology
Type
Hot-Swap Controllerr
Datasheet

Specifications of LTC1421CSW#TR

Applications
General Purpose
Internal Switch(s)
No
Voltage - Supply
3 V ~ 12 V
Operating Temperature
0°C ~ 70°C
Mounting Type
Surface Mount
Package / Case
24-SOIC (0.300", 7.50mm Width)
Linear Misc Type
Positive Low Voltage
Family Name
LTC1421
Package Type
SOIC W
Operating Supply Voltage (min)
3V
Operating Supply Voltage (max)
12V
Operating Temperature (min)
0C
Operating Temperature (max)
70C
Operating Temperature Classification
Commercial
Mounting
Surface Mount
Pin Count
24
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
LTC1421CSW#TRLTC1421CSW
Manufacturer:
ROHM
Quantity:
7
Company:
Part Number:
LTC1421CSW#TRLTC1421CSW-2.5
Manufacturer:
LT
Quantity:
44
FEATURES
TYPICAL APPLICATIO
APPLICATIO S
Hot Swap is a trademark of Linear Technology Corporation.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Allows Safe Board Insertion and Removal from a
Live Backplane
System Reset and Power Good Control Outputs
Programmable Electronic Circuit Breaker
User Programmable Supply Voltage Power-Up Rate
High Side Driver for Two External N-Channels
Controls Supply Voltages from 3V to 12V
Connection Inputs Detect Board Insertion or Removal
Undervoltage Lockout
Power-On Reset Input
Hot Board Insertion
Electronic Circuit Breaker
FAULT
DATA
GND
POR
BUS
V
V
V
DD
CC
EE
BACKPLANE
U
PC BOARD
U
R3
1k
D1
C1
1 F
24
2
4
3
1
CON2
AUXV
FAULT
POR
CON1
V
3
CCLO
23
1
CC
0.005
R1
SETLO GATELO V
GND
2
4
22
12
MTB50N06E
Q1
21
DISABLE
OUTLO
5
LTC1421
20
13
12
DESCRIPTIO
1
QuickSwitch
The LTC
that allow a board to be safely inserted and removed from a
live backplane. Using external N-channel pass transistors,
the board supply voltages can be ramped up at a program-
mable rate. Two high side switch drivers control the N-
channel gates for supply voltages ranging from 3V to 12V.
A programmable electronic circuit breaker protects against
shorts. Warning signals indicate that the circuit breaker
has tripped, a power failure has occurred or that the switch
drivers are turned off. The reset output can be used to
generate a system reset when the power cycles or a fault
occurs. The two connect inputs can be used with stag-
gered connector pins to indicate board insertion or re-
moval. The power-on reset input can be used to cycle the
board power or clear the circuit breaker.
The trip point of the ground sense comparator is set at
0.1V for LTC1421 and 2.5V for LTC1421-2.5.
The LTC1421/LTC1421-2.5 are available in 24-pin SO and
SSOP packages.
V
3
BEA
BEB
GND
CCHI
QS3384
1
19
0.025
V
CC
R2
®
SETHI GATEHI V
2
®
18
4
1/2 Si4936DY
1421/LTC1421-2.5 are Hot Swap
QuickSwitch IS A REGISTERED TRADEMARK
OF QUALITY SEMICONDUCTOR CORPORATION.
Q2
17
Hot Swap Controller
COMPOUT
0.47 F
PWRGD
COMP
COMP
RESET
RAMP
C3
OUTHI
CPON
LTC1421/LTC1421-2.5
REF
16
FB
10k
+
U
10
9
14
13
8
11
15
6
7
R4
20k
5%
DATA BUS
1 F
C2
0.1 F
1/2 Si4936DY
Q3
R5
16k
5%
R6
20k
1%
R7
7.15k
1%
+
+
+
C
C
LOAD
LOAD
C
LOAD
I/O
I/O
RESET
1421 TA01
P
TM
V
– 12V
1A
V
12V
1A
V
5V
5A
EE
DD
CC
controllers
1

Related parts for LTC1421CSW#TR

LTC1421CSW#TR Summary of contents

Page 1

... Controls Supply Voltages from 3V to 12V Connection Inputs Detect Board Insertion or Removal Undervoltage Lockout Power-On Reset Input U APPLICATIO S Hot Board Insertion Electronic Circuit Breaker , LTC and LT are registered trademarks of Linear Technology Corporation. Hot Swap is a trademark of Linear Technology Corporation. U TYPICAL APPLICATIO ...

Page 2

LTC1421/LTC1421-2 ABSOLUTE MAXIMUM (Note 1) Supply Voltage ( AUXV CCLO CCHI Input Voltage (Analog Pins) ..... – 0. Input Voltage (Digital Pins) ................... – 0.3V to 13.2V Output Voltage (Digital Pins) .. ...

Page 3

ELECTRICAL CHARACTERISTICS temperature range, otherwise specifications are at T SYMBOL PARAMETER I RAMP Pin Output Current RAMP I Charge Pump Output Current CP V GATEHI N-Channel Gate Drive GATEHI V GATELO N-Channel Gate Drive GATELO V Auxiliary V Output Voltage ...

Page 4

LTC1421/LTC1421-2 TYPICAL PERFORMANCE CHARACTERISTICS Reference Voltage vs Temperature 1.238 CCLO V = 12V CCHI 1.236 1.234 1.232 1.230 1.228 1.226 1.224 – 50 – 100 125 TEMPERATURE ( C) 1421 ...

Page 5

W U TYPICAL PERFORMANCE CHARACTERISTICS CPON Voltage vs Source Current (Charge Pump On – 0.5 – 1.0 – 1.5 SOURCE CURRENT (mA PIN FUNCTIONS CON1 (Pin 1): TTL Level Input ...

Page 6

LTC1421/LTC1421-2 PIN FUNCTIONS RAMP (Pin 10): Analog Power-Up Ramp Control Pin. By connecting an external capacitor between the RAMP and GATEHI, a positive linear voltage ramp on GATEHI and GATELO is generated on power-up with a slope ...

Page 7

W BLOCK DIAGRAM CCLO CC 24 AUXV CC 50mV CPON FAULT 1 CON1 2 CON2 3 POR 5 DISABLE 12 GND U W SWITCHI WAVEFOR S ...

Page 8

LTC1421/LTC1421-2 APPLICATIONS INFORMATION Hot Circuit Insertion When circuit boards are inserted into a live backplane, the supply bypass capacitors on the board can draw huge transient currents from the backplane power bus as they charge up. The transient ...

Page 9

U U APPLICATIONS INFORMATION PWRGD and RESET The LTC1421 uses a 1.232V bandgap reference, internal resistive divider and a precision voltage comparator to monitor V (Figure 6). OUTLO The reset threshold voltage for V OUTLO the FB pin connection as ...

Page 10

LTC1421/LTC1421-2 APPLICATIONS INFORMATION Figure 8c shows how the comparator can be used to generate a reset when the 12V supply (V below 10.8V. The 5V supply (V OUTLO reset when it dips below 4.65V. When the 12V supply ...

Page 11

U U APPLICATIONS INFORMATION is connected between REF (Pin 8) and the negative supply and the trip point of Comparator 2 set to GND. Soft Reset Generation A soft reset that doesn’t cycle the supply voltage can be generated externally ...

Page 12

LTC1421/LTC1421-2 APPLICATIONS INFORMATION When V collapses, there is enough energy stored on CCLO the 1 F capacitor connected to AUXV discharge circuitry alive long enough to fully turn off the external N-channels. Power N-Channel Selection The R of ...

Page 13

U U APPLICATIONS INFORMATION can usually be prevented by using logic that does not include the clamping diodes such as the QSI 74FCTT family from Quality Semiconductor using a data bus switch such as the 10-bit QS3384 QuickSwitch ...

Page 14

LTC1421/LTC1421-2 APPLICATIONS INFORMATION When CON1 and CON2 are both forced to ground for more than 20ms, the LTC1421 assumes that the board is fully connected to the host and power-up can begin. When V and V exceed the ...

Page 15

U U APPLICATIONS INFORMATION time point 2). Pulses less than 20ms on POR are ignored. CPON goes low. Both GATEHI and GATELO will be actively pulled down to GND. When V its reset threshold voltage, PWRGD will immediately pull low ...

Page 16

LTC1421/LTC1421-2 APPLICATIONS INFORMATION Board Removal Timing When the board is removed from the host, the sequence happens in reverse (Figure 17). Since CON1 and CON2 are the shortest pins, they break connection first and are internally pulled high ...

Page 17

U U APPLICATIONS INFORMATION 5V Only Applications The LTC1421 may be used in 5V only applications as shown in Figure 18. A soft reset can be generated from the backplane via an open-collector inverter driving the FB (Pin 11) or ...

Page 18

LTC1421/LTC1421-2 APPLICATIONS INFORMATION module. The ground pin for the LTC1421 is connected to – 48V; Zener diode D1 and resistor R1 provide the positive supply for the chip. Bypass capacitor C4 is protected against inrush current by P-channel ...

Page 19

U U APPLICATIONS INFORMATION W U CONNECTOR STAGGERED LTC1421/LTC1421-2.5 19 ...

Page 20

LTC1421/LTC1421-2 APPLICATIONS INFORMATION – 48V 0.1 F – 48V BACKPLANE PC BOARD 24V R1 5.1k 1/ 2.2 F 5.1V 25V FAULT 3 POR 1 S1 BACKPLANE PC BOARD Figure ...

Page 21

U U APPLICATIONS INFORMATION W U CONNECTOR STAGGERED LTC1421/LTC1421-2.5 21 ...

Page 22

LTC1421/LTC1421-2 APPLICATIONS INFORMATION – 48V BACKPLANE PC BOARD 5V BACKPLANE PC BOARD Figure 25. Hot Swappable 5V Supply with Overvoltage Protection ...

Page 23

... DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE 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 represen- tation that the interconnection of its circuits as described herein will not infringe on existing patent rights. ...

Page 24

... Q4 1W IRF7413 1 2 3.3V 11.5A CIRCUIT BREAKER 10A CIRCUIT BREAKER R6 100 1% 1/16W R8 5.62k 1% 1/16W GND LOGIC RST # R7 130k TP0610T 25V – 12V NO CIRCUIT BREAKER Q2 1421 F27 1/2 IRF7101 PCI PERIPHERAL 1421fc LT/LCG 0301 2K REV C • PRINTED IN USA LINEAR TECHNOLOGY CORPORATION 1996 ...

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