LTC1646 LINER [Linear Technology], LTC1646 Datasheet
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LTC1646
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LTC1646 Summary of contents
Page 1
... I/O pins during card insertion and extraction. PCI_RST# is logically combined on-chip with HEALTHY# in order to generate LOCAL_PCI_RST# which can be used to reset the CPCI card logic if either of the supply voltages is not within tolerance. The LTC1646 is available in the 16-pin narrow SSOP package 2.7Ω ...
Page 2
... Analog Voltages and Currents: (Pin 9) .................................... –0.3V to (3V (Pins 11, 13, 14) ........ –0.3V to (5V (Pin 10) .......................................................... ±20mA Operating Temperature Range: LTC1646C ............................................... 0°C to 70°C LTC1646I .............................................–40°C to 85°C Storage Temperature Range ..................–65°C to 150°C Lead Temperature (Soldering, 10 sec).................. 300°C ELECTRICAL CHARACTERISTICS ...
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... All voltages are referenced to ground unless otherwise specified. 3.3V Current Foldback Profile 0.005Ω 1 SENSE OUTPUT VOLTAGE (V) LTC1646 = 3.3V unless otherwise noted. MIN TYP ● 2 ● 1.15 1.25 ±0.08 ● ±0.08 ● ±0.08 ● ±0.08 ● ● 66 ● 66 ● 460 ● 0.9 ● ...
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... LTC1646 W U TYPICAL PERFOR A CE CHARACTERISTICS 5V Undervoltage Lockout IN Voltage vs Temperature 2.60 2.55 LOW-TO-HIGH TRANSITION 2.50 HIGH-TO-LOW TRANSITION 2.45 2.40 –50 – TEMPERATURE (°C) 1646 G04 3V Foldback Current Limit IN Voltage vs Temperature OUT OUT –50 – TEMPERATURE (°C) ...
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... G17 3V Input Current vs Temperature IN 480 475 470 465 460 455 450 445 –50 – 100 TEMPERATURE (°C) 1646 G20 LTC1646 Power Good Threshold Voltage vs Temperature (3V ) OUT 3.00 2.95 2.90 2.85 2.80 –50 – 100 TEMPERATURE (°C) 1646 G15 5V Input Current vs SENSE ...
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... LTC1646 W U TYPICAL PERFOR A CE CHARACTERISTICS RESETOUT, PWRGD and FAULT Output Low Voltage vs I 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0 (mA) SINK CTIO S RESETOUT (Pin 1): Open Drain Digital Output. Connect the CPCI LOCAL_PCI_RST# signal to the RESETOUT pin. RESETOUT is the logical combination of RESETIN and PWRGD (see Table 4) ...
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... RESETIN (Pin 16): Digital Input. Connect the CPCI PCI_RST# signal to the RESETIN pin. Pulling RESETIN low and IN will cause the RESETOUT pin to pull low. pin OUT LTC1646 and 5V SENSE IN pin is less than IN pin to IN 1646fa ...
Page 8
... LTC1646 W TEST DIAGRA DIAGRA Input Mode Window Voltage 3VONLY = ⎟ 5V ⎢ – 3.3V 3.3V 3VONLY IN IN OUT OUT IN V 3VONLY 3.3V V 5VIN –V 3VONLY 5V PWRGD 0V 1646 T01 t Overcurrent Fault Detect OC FALL TIME ≤ 1µ ...
Page 9
... The transient currents can cause glitches on the power bus, causing other boards in the system to reset. The LTC1646 is designed to turn a board’s supply voltages on and off in a controlled manner, allowing the board to be safely inserted or removed from a live CPCI slot without glitching the system power supplies ...
Page 10
... CPCI boards. The typical application is shown in Figure The main 3.3V and 5V inputs to the LTC1646 come from the medium length power pins. The long 3.3V, 5V connec- tor pins are shorted to the medium length 5V and 3.3V connector pins on the CPCI plug-in card and provide early power for the LTC1646’ ...
Page 11
... The timer period should be set longer than the maximum supply turn-on time but short enough to not exceed the maximum safe operating area of the pass transistor during a short-circuit. The timer period for the LTC1646 is given by: t TIMER As a design aid, the timer period as a function of the timing capacitor using standard values from 0.01µ ...
Page 12
... LTC1646 U U APPLICATIO S I FOR ATIO Table TIMER TIMER TIMER TIMER TIMER 0.01µF 2.5ms 0.22µF 0.022µF 5.5ms 0.33µF 0.033µF 8.25ms 0.47µF 0.047µF 11.8ms 0.68µF 0.068µF 17ms 0.82µF 0.082µF 20.5ms 1µF 0.1µF 25ms The TIMER pin is immediately pulled low when BD_SEL# goes high ...
Page 13
... F06 Two other parameters affect the value of the sense resis- tor. First is the tolerance of the LTC1646’s circuit breaker (4) threshold. The LTC1646’s nominal circuit breaker threshold is V –6mV/+9mV tolerance due to process variations. Second (5) is the tolerance (RTOL) in the sense resistor ...
Page 14
... I/O connector pins during board A insertion. The LTC1646 is also capable of generating precharge voltages other than 1V. Figure 8 shows a circuit that can be used in applications requiring a precharge Ω voltage less than 1V. The circuit in Figure 9 can be used for 0 0074 . = Ω ...
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... V(I/O) BD_SEL# V(I/O) HEALTHY# PCI_RST# GROUND I/O PIN 1 DATA BUS Z1: BZX84C6V2 W U Other CompactPCI Applications R1 R2 The LTC1646 can be easily configured for applications 16.2Ω 1.78Ω where no 5V supply is present by simply tying the 5V 14.7Ω 3.65Ω 5V pins to the 3V SENSE 12.1Ω 5.11Ω 3V pin (Figure 10). OUT 11Ω ...
Page 16
... Figure 12 allows the LTC1646 to be reset simply by pressing a pushbutton switch on the CPCI plug-in board. This arrangement eliminates the requirement to extract and reinsert the CPCI board in order to reset the LTC1646’s circuit breakers. PUSH- BUTTON SWITCH ...
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... LONG 3. 0.1µF Z1, Z2: BZX84C6V2 **ADDITIONAL DETAILS OMITTED FOR CLARITY Figure 13. Place Transient Protection Device Close to the LTC1646 W U LTC1646 circuit schematics, Zener diodes and snubber networks have been added to each 3.3V and 5V supply rail and should be used always. These protection networks should be mounted very close to the LTC1646’ ...
Page 18
... Power MOSFET and Sense Resistor Selection Table 6 lists some current MOSFET transistors that are available and Table 7 lists some current sense resistors that can be used with the LTC1646’s circuit breakers. Table 8 lists supplier web site addresses for discrete component mentioned throughout the LTC1646 data sheet. ...
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... TYP .008 – .012 (0.203 – 0.305) TYP LTC1646 .189 – .196* (4.801 – 4.978) .009 (0.229 REF .150 – .157** (3.810 – 3.988) ...
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... LTC4211 Hot Swap Controller with Multifunction Current Control Linear Technology Corporation 20 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 ● SENSE RESISTOR SO LTC1646* CURRENT FLOW TO SOURCE C TIMER W www.linear.com ● CURRENT FLOW TO LOAD OUT VIA ...