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LTC1643AL

LTC1643AL-1/LTC1643AH

1643afb

PCI-Bus Hot Swap

Controller

Hot Swappable PCI Supply

■

Allows Safe Board Insertion and Removal from a

Live PCI Slot

■

Works on either a Motherboard (LTC1643AH) or

CompactPCI

Card (LTC1643AL/LTC1643AL-1)

■

Controls –12V, 3.3V, 5V, 12V Supplies

■

Programmable Foldback Current Limit with

Circuit Breaker

■

User-Programmable Supply Voltage Power-Up Rate

■

High Side Drive for External N-Channel MOSFETs

■

–12V and 12V On-Chip Switches

■

Fault and Power-Good Outputs

■

Available in a Narrow 16-Lead SSOP Package

The LTC

1643A is a Hot Swap

controller that allows a board

to be safely inserted and removed from a live PCI-Bus slot.

Two external N-channel transistors control the 3.3V and 5V

supplies while on-chip switches control the –12V and 12V

supplies. All supply voltages can be ramped up at a program-

mable rate. An electronic circuit breaker protects all four

supplies against overcurrent faults. The foldback current limit

feature limits current spikes and power dissipation when

shorts occur and allows boards with large capacitances to be

powered up without tripping the circuit breaker. The PWRGD

output indicates when all of the supply voltages are within

tolerance and the FAULT output indicates an overcurrent

condition. The ON(LTC1643AH)/ON (LTC1643AL/

LTC1643AL-1)

pin is used to cycle the board power or reset

the circuit breaker. The LTC1643AL-1 has the ±12V power

good comparators disabled.

The LTC1643A is available in a 16-pin narrow SSOP package.

■

PCI-Based Servers

■

CompactPCI

Compliant Boards

FEATURES

DESCRIPTIO

APPLICATIO S

TYPICAL APPLICATION

0.005Ω

IRF7413

0.007Ω

10Ω

100Ω

0.047µF

3.3V

7.6A

GND

–12V

100mA

12V

500mA

10k

11 3 13 12 14

109

GND

12V

EEIN

FAULT

PWRGD

SENSE

OUT

LTC1643AH

OUT

12V

OUT

EEOUT

TIMER

GATE

1643A TA01

SYSTEM

POWER

SUPPLY

PCI

POWER

SYSTEM

CONTROLLER

0.1µF

RESET

LOGIC

RESET

, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.

Hot Swap is a registered trademark of Linear Technology Corporation.

All other trademarks are the property of their respective owners.

Summary of content (16 pages)

PAGE 1
LTC1643AL LTC1643AL-1/LTC1643AH PCI-Bus Hot Swap Controller U FEATURES DESCRIPTIO ■ The LTC®1643A is a Hot SwapTM controller that allows a board to be safely inserted and removed from a live PCI-Bus slot. Two external N-channel transistors control the 3.3V and 5V supplies while on-chip switches control the –12V and 12V supplies. All supply voltages can be ramped up at a programmable rate. An electronic circuit breaker protects all four supplies against overcurrent faults.
PAGE 2
LTC1643AL LTC1643AL-1/LTC1643AH U W U W W U W ABSOLUTE MAXIMUM RATINGS PACKAGE/ORDER INFORMATION (Note 1) Supply Voltages 12VIN ................................................................ 13.2V VEEIN .............................................................. –13.2V Input Voltage (Pin 5) ................ – 0.3V to (12VIN + 0.3V) Output Voltages (Pins 6, 7) ...... – 0.3V to (12VIN + 0.3V) Analog Voltages (Pins 3, 4, 9, 10 to 14) ........ – 0.3V to (12VIN + 0.3V) VEEOUT .....................
PAGE 3
LTC1643AL LTC1643AL-1/LTC1643AH DC ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = 25°C. V12VIN = 12V, VEEIN = – 12V, V3VIN = 3.
PAGE 4
LTC1643AL LTC1643AL-1/LTC1643AH U W TYPICAL PERFORMANCE CHARACTERISTICS Timer Current vs Temperature Gate ISINK vs Temperature 23.5 Gate Current vs Temperature 90 25.0 FAULT = LOW 22.5 80 22.0 21.5 21.0 GATE CURRENT (µA) 22.5 GATE ISINK (mA) 20.0 17.5 15.0 20.5 19.5 –50 –25 0 25 50 75 10.0 –50 –25 125 100 TEMPERATURE (°C) 50 25 75 0 TEMPERATURE (°C) 1643A G04 11.10 11.08 11.06 4.67 4.66 4.65 4.64 4.
PAGE 5
LTC1643AL LTC1643AL-1/LTC1643AH U W TYPICAL PERFORMANCE CHARACTERISTICS Timer Threshold Voltage vs Temperature 1.0 TIMER THRESHOLD VOLTAGE (V) CIRCUIT BREAKER TRIP FILTER TIME (µs) 15.50 15.25 15.00 14.75 14.50 14.25 14.00 –50 –25 50 25 75 0 TEMPERATURE (°C) 100 3.72 V12VIN – VTIMER 0.9 0.8 0.7 –50 –25 125 12VIN Supply Current vs Temperature 12VIN SUPPLY CURRENT (mA) Circuit Breaker Trip Filter Time vs Temperature 50 25 75 0 TEMPERATURE (°C) 100 0.87 0.86 0.
PAGE 6
LTC1643AL LTC1643AL-1/LTC1643AH U W TYPICAL PERFORMANCE CHARACTERISTICS 3VIN Undervoltage Lockout vs Temperature 70 2.452 2.450 2.448 2.446 2.444 2.442 –50 –25 50 25 75 0 TEMPERATURE (°C) 100 70 60 5VOUT = 5V 50 40 30 20 5VOUT = 0V 10 0 –50 –25 125 FOLDBACK CURRENT LIMIT VOLTAGE (mV) FOLDBACK CURRENT LIMIT VOLTAGE (mV) 2.
PAGE 7
LTC1643AL LTC1643AL-1/LTC1643AH U U U PIN FUNCTIONS the ON pin pulled low, the GATE pin is pulled high by a 62µA current source and the internal 12V and – 12V switches are turned on. When the ON pin is pulled low or the ON pin pulled high, the GATE pin will be pulled to ground by a 200µA current source and the 12V and – 12V switches turned off. The ON/ON pin is also used to reset the electronic circuit breaker.
PAGE 8
LTC1643AL LTC1643AL-1/LTC1643AH U U U PIN FUNCTIONS VEEOUT (Pin 15): –12V Supply Output. A 1.2Ω switch is connected between VEEIN and VEEOUT. VEEOUT must exceed –10.8V before the PWRGD signal can go high on the LTC1643AH and LTC1643AL. 12VOUT (Pin 16): 12V Supply Output. A 0.5Ω switch is connected between 12VIN and 12VOUT. 12VOUT must exceed 11.4V before the PWRGD signal can go high on the LTC1643AH and LTC1643AL.
PAGE 9
LTC1643AL LTC1643AL-1/LTC1643AH U U W U APPLICATIONS INFORMATION LTC1643A FEATURE SUMMARY 1. Allows safe board insertion and removal from either a motherboard (LTC1643AH) or CompactPCI board (LTC1643AL/LTC1643AL-1). Some ±12V supplies in CompactPCI applications are not well regulated and can violate the tolerance specification. For these applications, the LTC1643AL-1 should be used because the PWRGD signal does not depend on ±12V outputs. 2. Controls all four PCI supplies: –12V, 12V, 3.3V and 5V. 3.
PAGE 10
LTC1643AL LTC1643AL-1/LTC1643AH U U W U APPLICATIONS INFORMATION R1 Q1 1 0.007Ω 2 IRF7413 3 R2 1 0.005Ω 2 3 R6 10Ω Q2 IRF7413 3.3V 7.6A 4 GND SYSTEM POWER SUPPLY R5 10Ω 9 3VIN GND 1 12VIN 2 VEEIN 5 ON 8 PCI POWER SYSTEM CONTROLLER 5V 5A 4 R3 10k R4 10k 6 10 11 3VSENSE GATE R7 100Ω 3 13 3VOUT 5VIN 12 5VSENSE 5VOUT 12VOUT LTC1643AH VEEOUT FAULT TIMER 7 C1 0.047µF 14 PWRGD RESET 16 12V 500mA 15 –12V 100mA 4 C2 0.1µF LOGIC RESET 1643A F01 Figure 1.
PAGE 11
LTC1643AL LTC1643AL-1/LTC1643AH U W U U APPLICATIONS INFORMATION Timer During a power-up sequence, a 22µA current source is connected to the TIMER pin (Pin 4) and current limit faults are ignored until the voltage ramps to within 0.9V of 12VIN (Pin 1). This feature allows the chip to power up a PCI slot that can accept boards with widely varying capacitive loads on the supplies.
PAGE 12
LTC1643AL LTC1643AL-1/LTC1643AH U U W U APPLICATIONS INFORMATION ON 10V/DIV ON 10V/DIV TIMER 10V/DIV TIMER 10V/DIV GATE 10V/DIV GATE 10V/DIV 12VOUT 5V/DIV 12VOUT 5V/DIV 5VOUT 5V/DIV 3VOUT 5V/DIV 3VOUT 5V/DIV 5VOUT 5V/DIV VEEOUT 5V/DIV VEEOUT 5V/DIV FAULT 10V/DIV FAULT 10V/DIV PWRGD 10V/DIV PWRGD 10V/DIV 20ms/DIV 20ms/DIV 1643A F04 Figure 4. Power-Up into a Short on 3.3V Output Figure 5. Short Circuit on 5V Followed by Circuit Breaker Reset R1 1 0.007Ω 2 5V 3.3V 3 R2 1 0.
PAGE 13
LTC1643AL LTC1643AL-1/LTC1643AH U U W U APPLICATIONS INFORMATION R2 Q1 0.007Ω 1% 1 2 IRF7413 MED 5V R1 0.005Ω 1 1% 2 MED 3.3V 3 R11 10Ω† 5% C6 0.1µF 9 R8 1.2k 5% 3VIN 1 CompactPCI CONNECTOR HEALTHY# 2 R9 2k 5% 5 V(I/O) R13 2k 5% 3.3V 7.
PAGE 14
LTC1643AL LTC1643AL-1/LTC1643AH U U W U APPLICATIONS INFORMATION Increasing 12V and – 12V Current Capability for PCI Applications be reached when the internal current reaches 1A and the external current is 2A or 3A load current. The internal switches of the LTC1643A are designed for up to 500mA loads on 12V and 200mA on –12V. If more current is needed, then the circuits in Figure 8 can be used. For the –12V supply, N-channel transistor Q6 is used to provide the extra load current.
PAGE 15
LTC1643AL LTC1643AL-1/LTC1643AH U 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 TYP RECOMMENDED SOLDER PAD LAYOUT 1 .015 ± .004 × 45° (0.38 ± 0.10) .007 – .0098 (0.178 – 0.249) 2 3 4 5 6 .053 – .068 (1.351 – 1.727) 8 7 .004 – .0098 (0.102 – 0.
PAGE 16
LTC1643AL LTC1643AL-1/LTC1643AH U TYPICAL APPLICATIONS R2 Q1 0.007Ω 1% 1 2 IRF7413 MED 5V R1 0.005Ω 1% 1 2 MED 3.3V 3 R9 2k 5% HEALTHY# CompactPCI CONNECTOR 12V BD_SEL# R11 1Ω† 5% 3.3V 7.6A R4 10Ω 5% R3 10Ω 5% R8 1.2k 5% 9 1 R12 2k 5% 2 V(I/O) 6 5 R10 2k 5% 10 7 11 3 3VSENSE GATE 3VIN 5V 5A 4 4 V(I/O) D2* 12V 3 Q2 IRF7413 13 3VOUT 5VIN 12 R5 100Ω 5% 5VOUT 12VIN 12VOUT VEEIN VEEOUT ON LTC1643AL-1 GND TIMER 8 4 C7 0.1µF 16 15 NC LONG 3.