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LTC1647-1/

LTC1647-2/LTC1647-3

1647fa

TYPICAL APPLICATION

FEATURES DESCRIPTION

Dual Hot Swap Controllers

The LTC

1647-1/LTC1647-2/LTC1647-3 are dual Hot

Swap™ controllers that permit a board to be safely inserted

and removed from a live backplane.

Using external N-channel MOSFETs, the board supply

voltages can be ramped up at a programmable rate. A high

side switch driver controls the MOSFET gates for supply

voltages ranging from 2.7V to 16.5V. A programmable

electronic circuit breaker protects against overloads and

shorts. The ON pins are used to control board power or

clear a fault.

The LTC1647-1 is a dual Hot Swap controller with a

common V

pin, separate ON pins and is available in an

SO-8 package. The LTC1647-2 is similar to the LTC1647-1

but combines a fault status flag with automatic retry at

the ON pins and is also available in the SO-8 package. The

LTC1647-3 has individual V

pins, ON pins and FAULT

status pins for each channel and is available in a 16-lead

narrow SSOP package.

Dual Motherboard Resident Hot Swap Controller

APPLICATIONS

Allows Safe Board Insertion and Removal from a

Live Backplane

Programmable Electronic Circuit Breaker

FAULT Output Indication

Programmable Supply Voltage Power-Up Rate

High Side Drive for External MOSFET Switches

Controls Supply Voltages from 2.7V to 16.5V

Undervoltage Lockout

Hot Board Insertion

Electronic Circuit Breaker

Portable Computer Device Bays

Hot Plug Disk Drive

L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear

Technology Corporation. Hot Swap is a trademark of Linear Technology Corporation. All other

trademarks are the property of their respective owners.

ON1

12V

SUPPLY

ON2

10nF

DDZ23*

10Ω

20mΩ IRF7413

20mΩ

IRF7413

LOAD

OUT1

(2.5A)

OUT2

(2.5A)

10Ω

1647-1/2/3 TA01

SENSE 1

ON1

ON2

GND

GATE 1

SENSE 2 GATE 2

LTC1647-1

DDZ23*

LOAD

*REQUIRED FOR V

> 10V

10ms/DIV

5V/DIV

OUT

5V/DIV

GATE

10V/DIV

1647-1/2/3 TA01a

ON/OFF Sequence

Summary of content (22 pages)

PAGE 1
LTC1647-1/ LTC1647-2/LTC1647-3 Dual Hot Swap Controllers FEATURES DESCRIPTION n The LTC®1647-1/LTC1647-2/LTC1647-3 are dual Hot Swap™ controllers that permit a board to be safely inserted and removed from a live backplane. n n n n n n Allows Safe Board Insertion and Removal from a Live Backplane Programmable Electronic Circuit Breaker FAULT Output Indication Programmable Supply Voltage Power-Up Rate High Side Drive for External MOSFET Switches Controls Supply Voltages from 2.7V to 16.
PAGE 2
LTC1647-1/ LTC1647-2/LTC1647-3 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) Supply Voltage (VCC) ................................................17V Input Voltage (SENSE) ................. – 0.3V to (VCC + 0.3V) Input Voltage (ON) .....................................– 0.3V to 17V Output Voltage (FAULT) ..............................– 0.3V to 17V Output Voltage (GATE) ...........Internally Limited (Note 3) Operating Temperature Range C-Grade ...................................................
PAGE 3
LTC1647-1/ LTC1647-2/LTC1647-3 ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. SYMBOL PARAMETER VCC VCCX Supply Range CONDITIONS MIN Operating Range l TYP 2.7 MAX UNITS 16.5 V ICC VCC Supply Current (Note 4) ON1, ON2 = VCC1 = VCC2, ICC = ICC1 + ICC2 l 1.
PAGE 4
LTC1647-1/ LTC1647-2/LTC1647-3 PIN TABLES LTC1647-1 Pinout PIN LTC1647-3 Pinout DESCRIPTION PIN DESCRIPTION PIN DESCRIPTION PIN DESCRIPTION 1 VCC 5 GATE2 1 VCC 9 NC 2 ON1 6 GATE1 2 ON1 10 NC 3 ON2 7 SENSE2 3 FAULT1 11 NC 4 GND 8 SENSE1 4 ON2 12 GATE2 5 FAULT2 13 GATE1 6 NC 14 SENSE2 7 NC 15 SENSE1 8 GND 16 VCC2 LTC1647-1 Does Not Have the FAULT Status Feature.
PAGE 5
LTC1647-1/ LTC1647-2/LTC1647-3 TYPICAL PERFORMANCE CHARACTERISTICS ICC2 vs VCC2 (VGATE – VCC) vs VCC 5 TA = 25°C 25 16 VCC1 = 15V VCC1 = 12V 2 VCC1 = 3V 1 14 20 12 VGATE (V) 3 (VGATE – VCC) (V) 10 8 4 VCC1 = 5V 0 2 4 6 0 0 2 4 6 8 0 10 12 14 16 18 20 VCC (V) 1647-1/2/3 G04 (VGATE – VCC) vs Temperature VGATE vs Temperature 8 VGATE (V) VCC = 15V VCC = 3V 6 VCC = 5V VCC = 12V 20 15 VCC = 3V 10 4 5 VCC = VCC1 = VCC2 2 VCC = VCC1 = VCC2 0 –75 –50 –25 0 25 50 75 100 125
PAGE 6
LTC1647-1/ LTC1647-2/LTC1647-3 TYPICAL PERFORMANCE CHARACTERISTICS GATE Output Sink Current vs Temperature GATE Output Sink Current vs VCC GATE OUTPUT SINK CURRENT (μA) GATE OUTPUT SINK CURRENT (μA) 80 70 60 50 40 30 20 10 0 60 55 TA = 25°C 90 VCC = 5V 54 GATE FAST PULL-DOWN CURRENT (mA) 100 53 52 51 50 49 48 47 46 0 2 4 6 8 45 –75 –50 –25 10 12 14 16 18 20 VCC (V) 30 20 10 0 –75 –50 –25 58 56 54 52 50 48 46 44 42 40 0 25 50 75 100 125 150 TEMPERATURE (°C) 0 2 4 6 8 58 56 54 2.
PAGE 7
LTC1647-1/ LTC1647-2/LTC1647-3 TYPICAL PERFORMANCE CHARACTERISTICS FAULT VOL vs VCC FAULT VOL vs Temperature 2.0 1.6 1.4 1.4 FAULT VOL (V) FAULT VOL (V) 1.6 1.2 IOL = 5mA 1.0 0.8 0.6 TA = 25°C VCC = 5V 1.8 0.8 1.2 1.0 IOL = 5mA 0.8 0.4 0.2 0.4 IOL = 1mA 0.2 0 2 4 6 8 IOL = 1mA 0.2 0 –75 –50 –25 10 12 14 16 18 20 VCC (V) 0 0 25 50 75 100 125 150 TEMPERATURE (°C) 1647-1/2/3 G22 VCC = 5V VCC = 12V 0.
PAGE 8
LTC1647-1/ LTC1647-2/LTC1647-3 PIN FUNCTIONS VCC1 (LTC1647-3): Channel 1 Positive Supply Input. The supply range for normal operation is 2.7V to 16.5V. The supply current, ICC1, is typically 1mA. Channel 1’s undervoltage lockout (UVLO) circuit disables GATE 1 until the supply voltage at VCC1 is greater than VLKO (typically 2.45V). GATE 1 is held at ground potential until UVLO deactivates. If ON1 is high and VCC1 is above the UVLO threshold voltage, GATE 1 is pulled high by a 10μA current source.
PAGE 9
LTC1647-1/ LTC1647-2/LTC1647-3 BLOCK DIAGRAMS LTC1647-1 + – 50mV CHANNEL ONE + CP – SENSE1 8 1.21V 10μA + 50μs FILTER 6 GATE1 – ON1 2 50μA 2.45V UVL VCC 1 GND 4 REFERENCE CHARGE PUMP 1.21V CP CHANNEL TWO (DUPLICATE OF CHANNEL ONE) SENSE2 7 5 GATE2 ON2 3 1647-1/2/3 BD1 LTC1647-2 + – 50mV CHANNEL ONE + CP – SENSE1 8 1.21V 10μA + 50μs FILTER ON1/FAULT1 2 6 GATE1 – 50μA 2.45V UVL FAULT VCC 1 GND 4 SENSE2 7 REFERENCE 1.
PAGE 10
LTC1647-1/ LTC1647-2/LTC1647-3 BLOCK DIAGRAMS LTC1647-3 VCC1 1 + – 50mV CHANNEL ONE + CP – SENSE1 15 1.21V 10μA + 50μs FILTER ON1 2 FAULT1 3 GND 8 13 GATE1 – 50μA 2.45V UVL FAULT REFERENCE CHARGE PUMP 1.21V CP VCC SELECTION VCC2 16 SENSE2 14 12 GATE2 CHANNEL TWO (DUPLICATE OF CHANNEL ONE) ON2 4 FAULT2 5 1647-1/2/3 BD3 APPLICATIONS INFORMATION VCC Selection Circuit Electronic Circuit Breaker The LTC1647-3 features separate supply inputs (VCC1 and VCC2) for each channel.
PAGE 11
LTC1647-1/ LTC1647-2/LTC1647-3 APPLICATIONS INFORMATION R1 0.01Ω Q1 IRF7413 VCC VOUT + R3 10k ON FAULT CLOAD R2 10Ω 2 1 15 13 VCC SENSE GATE ON1 3 FAULT 8 C1 10nF *D1 DDZ23 LTC1647-3 GND *D1 REQUIRED FOR VCC > 10V 1647-1/2/3 F01 Figure 1. Supply Control Circuitry tFAULT tRESET VGATE VFAULT 1647-1/2/3 F02 Figure 2. Current Fault Timing Q1 IRF7413 R1 0.01Ω VCC VOUT + C3 10nF R3 1.5k CLOAD R2 10Ω C1 10nF VCC SENSE IPK = 7.5A IAV = 2.
PAGE 12
LTC1647-1/ LTC1647-2/LTC1647-3 APPLICATIONS INFORMATION an input supply greater than 10V at VCC1 or VCC2, a 24V Zener is recommended between the corresponding GATE1 or GATE2 pin and GND as shown in Figures 1 and 4. The RDS(ON) of the external pass transistor must be low to make VDS a small percentage of VCC. At VCC = 3.3V, VDS + VCB = 0.1V yields 3% error at maximum load current. This restricts the choice of MOSFETs to very low RDS(ON). At higher VCC voltages, the RDS(ON) requirement can be relaxed.
PAGE 13
LTC1647-1/ LTC1647-2/LTC1647-3 APPLICATIONS INFORMATION Autoretry The LTC1647-2 and LTC1647-3 are designed to allow an automatic reset of the electronic circuit breaker after a fault condition occurs. This is accomplished by pulling the ON/FAULT (LTC1647-2) pin or the ON and FAULT pins tied together (LTC1647-3) high through a resistor, R3, as shown in Figure 7. An autoretry sequence begins if a fault occurs. If the circuit breaker trips, FAULT pulls the ON pin low.
PAGE 14
LTC1647-1/ LTC1647-2/LTC1647-3 APPLICATIONS INFORMATION Supply Glitching VID Power Controller LTC1647 Hot Swap circuits on the backplane are generally used to provide power-up/down sequence at insertion/ removal as well as overload/short-circuit protection. If a short-circuit occurs at supply ramp-up, the circuit breaker trips. The partially enhanced MOSFET, Q1, is easily disconnected without any supply glitch.
PAGE 15
LTC1647-1/ LTC1647-2/LTC1647-3 APPLICATIONS INFORMATION BACKPLANE CONNECTOR STAGGERED PCB EDGE CONNECTOR Q1 R1 VCC VOUT + R4 CLOAD R5 R2 ON R3 Q2 2 3 FAULT 8 1 15 13 VCC SENSE GATE C1 ON FAULT LTC1647-3 GND 8a. HOT SWAP CONTROLLER ON MOTHERBOARD BACKPLANE CONNECTOR STAGGERED PCB EDGE CONNECTOR Q1 R1 VCC + R4 VOUT CLOAD R2 FAULT R3 2 3 8 1 15 13 VCC SENSE GATE C1 ON FAULT LTC1647-3 GND 8b. HOT SWAP CONTROLLER ON DAUGHTERBOARD 1647-1/2/3 F08 Figure 8.
PAGE 16
LTC1647-1/ LTC1647-2/LTC1647-3 APPLICATIONS INFORMATION R1 0.01Ω 8' Q1 IRF7413 + 12V + – POWER LEADS VOUT CLOAD R2 10Ω SCOPE PROBE C1 10nF *D1 DDZ23 LTC1647 1647-1/2/3 F09 * REQUIRED FOR VCC >10V 24V 4V/DIV 4V/DIV 24V 0V 0V 1μs/DIV 1μs/DIV 1647-1/2/3 F09a 9a. Undamped VCC Waveform (48” Leads) 1647-1/2/3 F09b 9b. Undamped VCC Waveform (8” Leads) Figure 9.
PAGE 17
LTC1647-1/ LTC1647-2/LTC1647-3 APPLICATIONS INFORMATION Q1 IRF7413 R1 0.01Ω VOUT R2 10Ω D1* C1 10nF 2V/DIV PCB EDGE CONNECTOR + – POWER LEADS 12V CLOAD *D2 DDZ23 LTC1647 0V 1647-1/2/3 F10 1μs/DIV ON SEMICONDUCTOR * 1SMA12CAT3, REQUIRED FOR VCC > 10V 1647-1/2/3 F10a VCC Waveform Clamped by a Transient Suppressor Figure 10. Transient Suppressor Clamp POWER LEADS PCB EDGE CONNECTOR 12V + – BACKPLANE CONNECTOR R1 0.01Ω Q1 IRF7413 + R3 10Ω VOUT CLOAD R2 10Ω C1 0.
PAGE 18
LTC1647-1/ LTC1647-2/LTC1647-3 APPLICATIONS INFORMATION + – Q1 IRF7413 L1 2μH R2 10Ω C2 100μF C1 10nF *D1 DDZ23 LTC1647 *REQUIRED FOR VCC > 10V BOARD WITH POSSIBLE SHORT-CIRCUIT FAULT 12V + R1 0.01Ω BACKPLANE CONNECTOR SUPPLY GLITCH 1647-1/2/3 F12 Figure 12. Supply Glitch GATE OF MOSFET 5V/DIV GATE OF MOSFET 5V/DIV VCC 5V/DIV VCC 5V/DIV VCC SHORT-CIRCUIT SUPPLY CURRENT 10A/DIV VCC SHORT-CIRCUIT SUPPLY CURRENT 50A/DIV 5μs/DIV 1647-1/2/3 F12a 12a.
PAGE 19
LTC1647-1/ LTC1647-2/LTC1647-3 R1 0.1Ω 3.3V VID SUPPLY Q1 1/2 MMDF3N02HD R3** R2 10Ω ON1 CONNECTOR #1 APPLICATIONS INFORMATION DEVICE #1 + CLOAD* R4** 1394 PHY AND/OR USB PORT R5 10Ω 8 C3 0.1μF 1 2 3 4 R6 10Ω FAULT2 C1 10nF 6 SENSE1 GATE1 VCC ON1/FAULT1 CLOAD IS USER-SELECTED BASED ON THE DEVICE REQUIREMENTS ** R3, R4, R7 AND R8 ARE OPTIONAL DISCHARGE RESISTORS WHEN DEVICES ARE POWERED-OFF Q1, Q2: ON SEMICONDUCTOR * LTC1647-2 ON2/FAULT2 GND SENSE2 GATE2 7 C6 0.
PAGE 20
LTC1647-1/ LTC1647-2/LTC1647-3 PACKAGE DESCRIPTION GN Package 16-Lead Plastic SSOP (Narrow .150 Inch) (Reference LTC DWG # 05-08-1641) .189 – .196* (4.801 – 4.978) .045 ±.005 .009 (0.229) REF 16 15 14 13 12 11 10 9 .254 MIN .150 – .165 .229 – .244 (5.817 – 6.198) .0165 ±.0015 .150 – .157** (3.810 – 3.988) .0250 BSC RECOMMENDED SOLDER PAD LAYOUT 1 .015 ± .004 s 45° (0.38 ± 0.10) .007 – .0098 (0.178 – 0.249) 4 2 3 5 6 .0532 – .0688 (1.35 – 1.75) 7 8 .004 – .0098 (0.102 – 0.
PAGE 21
LTC1647-1/ LTC1647-2/LTC1647-3 REVISION HISTORY REV DATE DESCRIPTION PAGE NUMBER A 10/10 Replaced Typical Application circuit 1 Updated Order Information section 2 Revised GATE1 description in Pin Functions section Revised Figures 1, 4, 6, 7, 8, 9, 10, 11 and 12 in Applications Information section 8 11, 12, 15, to 18 Updated references to Figure 12a and 12b in Applications Information section 14 Revised Figure 14 in Typical Applications and updated Related Parts list 20 1647fa Information f
PAGE 22
LTC1647-1/ LTC1647-2/LTC1647-3 TYPICAL APPLICATION Hot Swapping Two Supplies Two separate supplies can be independently controlled by using the LTC1647-3. In some applications, sequencing between the two power supplies is a requirement. For example, it may be necessary to ramp-up one supply first before allowing the second supply to power-up, as well as requiring that this same supply ramp-down last on power-down.