LTC4251-1IS6#TR Linear Technology, LTC4251-1IS6#TR Datasheet
LTC4251-1IS6#TR
Specifications of LTC4251-1IS6#TR
LTC42511IS6TR
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LTC4251-1IS6#TR Summary of contents
Page 1
... A multifunction timer delays initial start-up and controls the circuit breaker’s response time. The LTC4251 UV/OV thresholds are designed to match the standard telecom operating range of – 43V to –75V. The LTC4251-1 UV/OV thresholds extend the operating range to encompass – ...
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... LTC4251CS6#PBF LTC4251CS6#TRPBF LTC4251IS6#PBF LTC4251IS6#TRPBF LTC4251-1CS6#PBF LTC4251-1CS6#TRPBF LTC4251-1IS6#PBF LTC4251-1IS6#TRPBF LTC4251-2CS6#PBF LTC4251-2CS6#TRPBF LTC4251-2IS6#PBF LTC4251-2IS6#TRPBF Consult LTC Marketing for parts specified with wider operating temperature ranges. Consult LTC Marketing for information on non-standard lead based finish parts. For more information on lead free part marking, go to: ...
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... Timer On (Circuit Breaker, Sourcing), V TMR Timer Off (Cooling Cycle, Sinking), V TMR LTC4251/LTC4251-1 Note 2: All currents into device pins are positive; all currents out of device pins are negative. All voltages are referenced to V specified. Note 3: UV/ refers for the LTC4251- 1000 T = –40°C ...
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... SENSE GATE –55 –35 – 105 125 TEMPERATURE (°C) 425112 G10 4 UV/ refers for the LTC4251-2. Undervoltage Lockout V vs LKO Temperature 12.0 11.5 11.0 10.5 10.0 9.5 9.0 8.5 8.0 85 105 –55 –35 – 125 TEMPERATURE (°C) 425112 G05 Analog Current Limit Voltage V ...
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... TIMER = 0V GATE = HIGH –28 V – 50mV SENSE EE –30 –55 –35 – 105 125 TEMPERATURE (°C) 425112 G19 LTC4251/LTC4251-1/ UV/ refers for the LTC4251- Temperature GATEL 0.8 UV/ 0V, 0.7 TMR GATE THRESHOLD BEFORE RAMP-UP 0.6 0.5 0.4 0.3 0.2 0 105 –55 –35 – ...
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... TEMPERATURE (°C) 1.3 1.2 1.1 1.0 0.9 0.8 0.7 0.6 0 105 125 425112 G25 UV/ refers for the LTC4251-2. I (Circuit Breaking, Sourcing) TMR vs Temperature 280 260 240 220 200 180 125 –55 –35 – TEMPERATURE (°C) 425112 G23 t and t ...
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... PIN FUNCTIONS UV/OV refers to the UV pin for the LTC4251-2. The OV comparator in the LTC4251-2 is disabled. All references in the text to overvoltage, OV, V SENSE (Pin 1): Circuit Breaker/Current Limit SENSE Pin. Load current is monitored by sense resistor R between SENSE and V , and controlled in three steps SENSE exceeds V ...
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... LTC4251-2 BLOCK DIAGRAM – V OVHI + V EE – UV/OV UVLO – 230µA 5.8µ TIMER 4 – 5.8µ *UV FOR THE LTC4251-2 ** THE OV COMPARATOR IS DISABLED FOR LTC4251 OV** 58µ LOGIC V IN 22µ 10mV 5k OS – 50mV + – – GATE + 0.5V – + FCL 200mV + – ...
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... OPERATION Note that for simplicity, the following assumptions are made in the text. Firstly, UV/OV also means the UV pin of the LTC4251-2. Secondly, all overvoltage conditions and references to OV comparator in this part is disabled. Hot Circuit Insertion When circuit boards are inserted into a live backplane, the supply bypass capacitors can draw huge transient currents from the power bus as they charge ...
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... SENSE > 50mV, TIMER charges this case, the S LTC4251/LTC4251-1/LTC4251-2 will eventually shut down. Low impedance failures on the load side of the LTC4251/ LTC4251-1/LTC4251-2 coupled with 48V or more driving potential can produce current slew rates well in excess of 50A/µs. Under these conditions, overshoot is inevitable. A ...
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... OV turning off at V pin to OV turning The UV and OV trip point ratio for LTC4251 is designed to match the standard telecom operating range of 43V to 75V. The LTC4251-2 implements a UV threshold of 43V only. A divider (R1, R2) is used to scale the supply voltage. Using may be split into two R1 = 402k and ...
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... Figure 3. Circuit Breaker Response Time (1) GATE GATE is pulled low to V conditions: in UVLO, during the initial timing cycle overvoltage condition, or when the LTC4251/LTC4251-1/ LTC4251-2 are latched off after a short-circuit. When GATE turns on, a 58µA current source charges the MOSFET gate , S and any associated external capacitance. V charges to T drive to no more than 14 ...
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... Figure 4, Trace 1, can rob charge from output capacitors on adjacent cards. When the faulty card shuts down, current flows in to refresh the capacitors. If LTC4251, LTC4251-1 or LTC4251-2s are used throughout, they respond by limiting the inrush current to a value of 100mV/R will recharge long before C – ...
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... L(MAX) where 40mV represents the guaranteed minimum circuit breaker threshold. During the initial charging process, the LTC4251/ LTC4251-1/LTC4251-2 may operate the MOSFET in current limit, forcing 80mV to 120mV across R inrush current is given by: 80mV I = INRUSH(MIN Maximum short-circuit current limit is calculated using ...
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... V SENSE pins are strongly recommended. The drawing in Figure 6 illustrates the correct way of making connections between the LTC4251/LTC4251-1/LTC4251-2 and the sense resistor. PCB layout should be balanced and symmetrical to minimize wiring errors. In addition, the PCB layout for the sense resistor should include good thermal management techniques for optimal sense resistor power dissipation ...
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... In this example as shown in Figure 8, power is delivered through long connector pins whereas the UV/OV divider makes contact through a short pin. This ensures the power connections are firmly established before the LTC4251/ LTC4251-1/LTC4251-2 are activated. At time point 1, the power pins make contact and V ramps through time point ...
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... GATE < V UVHI IN LKO LKH TMRL TIMER CLEARS TMRH 5.8µA 230µA V TMRL 58µA INITIAL TIMING CYCLE START-UP CYCLE LTC4251/LTC4251-1/ LTC4251-2 AND SENSE < GATEL CB , CHECK GATE < V AND SENSE < TMRL GATEL CB 5.8µA 5.8µA 58µA V ACL V CB 425112 F07 ) EE AND SENSE < ...
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... LTC4251/LTC4251-1/ LTC4251-2 APPLICATIONS INFORMATION Analog Current Limit and Fast Current Limit In Figure 13a, when SENSE exceeds V by the analog current limit amplifier loop. When SENSE drops below V , GATE is allowed to pull up. In Figure ACL 13b, when a severe fault occurs, SENSE exceeds V and GATE immediately pulls down until the analog current amplifier can establish control ...
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... DROPS BELOW V AND GATE RESTARTS. UV/0V OVLO OVLO 230µA 5.8µA 5.8µA 58µA 58µA V ACL V CB LTC4251/LTC4251-1/ LTC4251 CHECK GATE < V AND SENSE < TMRL GATEL CB 10 5.8µA 5.8µA 58µA V ACL V CB 425112 F10 ) EE 5.8µA 425112 F11 ...
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... LTC4251/LTC4251-1/ LTC4251-2 APPLICATIONS INFORMATION TMRL TIMER 230µA 5.8µA GATE V ACL V SENSE CB V OUT CB FAULT (12a) Momentary Circuit-Breaker Fault TIMER GATE SENSE V Figure 12. Timer Behavior (All Waveforms are Referenced TIMER 5.8µA GATE SENSE V OUT 425112 F12a TIMER LATCHES OFF ...
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... Fast Current Limit Fault 1 5.8µA TIMER V TMRL 5.8µA GATE SENSE INTERNAL 425112 F14 SOFT-START REFERENCE ) EE Figure 15. Internal Soft-Start Timing (All Waveforms are Referenced to V LTC4251-2 TIMER LATCHES OFF 2 5.8µA TMRH V ACL V CB 425112 F13b ) EE END OF INITIAL TIMING CYCLE ...
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... LTC4251/LTC4251-1/ LTC4251-2 PACKAGE DESCRIPTION 0.62 0.95 MAX REF 3.85 MAX 2.62 REF RECOMMENDED SOLDER PAD LAYOUT PER IPC CALCULATOR 0.20 BSC DATUM ‘A’ 0.30 – 0.50 REF NOTE: 1. DIMENSIONS ARE IN MILLIMETERS 2. DRAWING NOT TO SCALE 3. DIMENSIONS ARE INCLUSIVE OF PLATING 4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR 5 ...
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... Revised Short-Circuit Operation section 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 representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights. LTC4251/LTC4251-1/ LTC4251-2 PAGE NUMBER ...
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... DDZ13B** 1µ UV/OV GATE C1 LTC4251-1 10nF 4 1 TIMER SENSE 220nF Figure 17. Power-Limited Circuit Breaker Application COMMENTS Negative High Voltage Supplies from –10V to –80V Supplies from 9V to 80V, Latched Off/Autoretry 3V to 16.5V, Overvoltage Protection up to 33V ±1V UV and ±1.5V OV Threshold Accuracy, ± 200V Transient Protection, Drives Three Optoisolators for Status Active Current Limiting, Supplies from – ...