LT1640AL LINER [Linear Technology], LT1640AL Datasheet
LT1640AL
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LT1640AL Summary of contents
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NOT RECOMMENDED FOR NEW DESIGNS Please See LTC4252B/LTC4252C for Drop-In Replacement FEATURES n Allows Safe Board Insertion and Removal from a Live – 48V Backplane n Floating Topology Permits Very High Voltage Operation n Programmable Analog Current Limit With Circuit ...
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LTC4252-1/LTC4252-2 LTC4252A-1/LTC4252A-2 ABSOLUTE MAXIMUM RATINGS All Voltages Referred to V (Note 1) EE Current into V (100μs Pulse) .............................100mA DRAIN Pin Minimum Voltage ........................ – 0.3V IN Input/Output Pins (Except SENSE and DRAIN) Voltage .......... –0.3V to ...
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ELECTRICAL CHARACTERISTICS temperature range, otherwise specifications are at T SYMBOL PARAMETER V V – V Zener Voltage – V Zener Dynamic Impedance Supply Current Undervoltage Lockout ...
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LTC4252-1/LTC4252-2 LTC4252A-1/LTC4252A-2 ELECTRICAL CHARACTERISTICS temperature range, otherwise specifications are at T SYMBOL PARAMETER I TIMER Pin Current TMR Δ 50μA) – TMRACC TMR DRN TMR ΔI 0μA)]/ΔI DRN DRN V DRAIN Pin ...
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TYPICAL PERFORMANCE CHARACTERISTICS V vs Temperature Z 14 2mA IN 14.0 13.5 13.0 12.5 12.0 85 105 –55 –35 – TEMPERATURE (°C) 425212 G04 1000 T = –40°C A ...
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LTC4252-1/LTC4252-2 LTC4252A-1/LTC4252A-2 TYPICAL PERFORMANCE CHARACTERISTICS V vs Temperature SS 2.40 2.35 2.30 2.25 2.20 2.15 2.10 2.05 2.00 –55 –35 – 105 125 TEMPERATURE (°C) 425212 G26 V vs Temperature OS 11.0 10.8 10.6 10.4 ...
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TYPICAL PERFORMANCE CHARACTERISTICS V vs Temperature GATEH 3 – GATEH IN GATE I = 2mA 3.4 IN (MS ONLY) 3.2 3.0 2.8 2.6 2.4 2.2 2.0 –55 –35 – 105 ...
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LTC4252-1/LTC4252-2 LTC4252A-1/LTC4252A-2 TYPICAL PERFORMANCE CHARACTERISTICS I (Circuit Breaker, Sourcing) TMR vs Temperature 280 TIMER = 0μA DRN 260 240 220 200 180 –55 –35 – 105 TEMPERATURE (°C) 425212 G22 I vs ...
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TYPICAL PERFORMANCE CHARACTERISTICS I vs Temperature PGH PWRGD (MS ONLY –55 –35 – 105 125 TEMPERATURE (°C) 425212 G38 PIN FUNCTIONS (MS/MS8) V (Pin ...
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LTC4252-1/LTC4252-2 LTC4252A-1/LTC4252A-2 PIN FUNCTIONS (MS/MS8) V (Pin 5/Pin 4): Negative Supply Voltage Input. Connect EE this pin to the negative side of the power supply. GATE (Pin 6/Pin 5): N-Channel MOSFET Gate Drive Output. This pin is pulled high by ...
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BLOCK DIAGRAM – 6.15V (5.09V – – 2.925V ( (3.08V 230μA IN – 4V 5.8μA + TIMER – V 5.8μ ...
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LTC4252-1/LTC4252-2 LTC4252A-1/LTC4252A-2 OPERATION 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. The flow of current damages the connector pins and ...
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OPERATION Two modes of operation are possible during the time the MOSFET is first turning on, depending on the values of external components, MOSFET characteristics and nominal design current. One possibility is that the MOSFET will turn on gradually so ...
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LTC4252-1/LTC4252-2 LTC4252A-1/LTC4252A-2 APPLICATIONS INFORMATION SHUNT REGULATOR A fast responding shunt regulator clamps the V (VZ). Power is derived from –48RTN by an external current limiting resistor 1μF decoupling capacitor supply transients and contributes a short ...
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APPLICATIONS INFORMATION and R2 = 32.4k gives a typical operating range of 43.2V to 82.5V. The undervoltage shutdown and overvoltage recovery thresholds are then 39.2V and 74.4V. 1% divider resistors are recommended to preserve threshold accuracy. The R1-R2 divider values ...
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LTC4252-1/LTC4252-2 LTC4252A-1/LTC4252A-2 APPLICATIONS INFORMATION conditions are met. A high-to-low transition in the UV comparator immediately shuts down the LTC4252, pulls the MOSFET gate low and resets the latched PWRGD high. Overvoltage conditions detected by the OV compara- tor will also ...
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APPLICATIONS INFORMATION (μF) T 0.1 0. FAULT DUTY CYCLE (%) Figure 5. Circuit-Breaker Response Time 2.5% or more will eventually trip the circuit breaker and shut down the LTC4252. Figure 5 ...
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LTC4252-1/LTC4252-2 LTC4252A-1/LTC4252A-2 APPLICATIONS INFORMATION and eliminates current spikes at insertion. A large external gate-source capacitor is thus unnecessary for the purpose of compensating C . Instead, a smaller value (≥ 10nF) GD capacitor C is adequate. C also provides compensation ...
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APPLICATIONS INFORMATION A low impedance short on one card may influence the behavior of others sharing the same backplane. The initial glitch and backplane sag as seen in Figure 6 Trace 1, can rob charge from output capacitors on adjacent ...
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LTC4252-1/LTC4252-2 LTC4252A-1/LTC4252A-2 APPLICATIONS INFORMATION Approximating a linear charging rate zero, the I component in Equation (3) DRN(MAX) DRN can be approximated with 0.5 • I DRN(MAX) equation, TIMER capacitor C is given by ...
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APPLICATIONS INFORMATION 60 NTY100N10 IRF3710 IRF540S 20 IRF530S 10 IRF740 0 0 2000 4000 MOSFET C (pF) ISS Figure 7. Recommended Compensation Capacitor C vs MOSFET C C ISS As seen in Figure 6 previously, at the ...
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LTC4252-1/LTC4252-2 LTC4252A-1/LTC4252A-2 APPLICATIONS INFORMATION V CLEARS V IN LKO 1 2 GND – (–48RTN) – (–48V) UV/ LKO IN TIMER GATE V GATEL SS SENSE V OUT DRAIN PWRGD Figure 9. System Power-Up Timing (All ...
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APPLICATIONS INFORMATION UV CLEARS GND – (–48RTN) – (–48V) V UV/OV UVHI LKO TIMER GATE V GATEL SS SENSE V OUT DRAIN PWRGD Figure 10. Power-Up Timing with a Short Pin ...
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LTC4252-1/LTC4252-2 LTC4252A-1/LTC4252A-2 APPLICATIONS INFORMATION Undervoltage Timing In Figure 11 when UV pin drops below V the LTC4252 shuts down with TIMER, SS and GATE all pulling low. If current has been flowing, the SENSE pin voltage decreases to zero as ...
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APPLICATIONS INFORMATION UV/OV CLEARS V , CHECK OV CONDITION, GATE < V UVHI UV/OV OVERSHOOTS V UV/OV DROPS BELOW OVHI V OVLO UV/OV V UVHI TIMER GATE V GATEL SS SENSE DRAIN PWRGD Figure 12. ...
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LTC4252-1/LTC4252-2 LTC4252A-1/LTC4252A-2 APPLICATIONS INFORMATION TMRH 5.8μA TIMER DRN GATE SS V ACL V CB SENSE V OUT DRAIN PWRGD CB FAULT (14a) Momentary Circuit-Breaker Fault Figure 14. Circuit-Breaker Timing Behavior (All Waveforms Are Referenced to V the ...
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APPLICATIONS INFORMATION TIMER GATE SENSE DRAIN PWRGD Figure 15. Pushbutton Reset of LTC4252-1’s Latched Fault (All Waveforms Are Referenced to V CIRCUIT BREAKER TIMES OUT 1 2 5.8μA DRN 5.8μA TIMER V TMRL GATE SS SENSE V OUT DRAIN PWRGD ...
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LTC4252-1/LTC4252-2 LTC4252A-1/LTC4252A-2 APPLICATIONS INFORMATION Analog Current Limit and Fast Current Limit In Figure 17a, when SENSE exceeds V regulated by the analog current limit amplifier loop. When SENSE drops below V , GATE is allowed to pull up. In ACL ...
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APPLICATIONS INFORMATION END OF INTIAL TIMING CYCLE 12 34 567 7a V TMRH TIMER V TMRL GATE V GS(th) 58μ ACL SENSE DRAIN PWRGD (18a) Without External C Figure 18. Soft-Start Timing (All Waveforms ...
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LTC4252-1/LTC4252-2 LTC4252A-1/LTC4252A-2 APPLICATIONS INFORMATION –48RTN –48RTN (SHORT PIN) R1 392k 1% R2 30. 10nF –48V *FMMT493 **DIODES, INC † Circuit Breaker with Foldback Current Limit Figure 20 shows the LTC4252A in a foldback current limit application. When V ...
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APPLICATIONS INFORMATION –48RTN –48RTN (SHORT PIN) R1 392k 1% C1 10nF R2 30.1k 1% –48V *MOC207 Figure 20. Circuit Breaker with Foldback Current Limit Application –48RTN –48RTN (SHORT PIN) R1 392k 1% C1 10nF R2 30.1k 1% –48V *MOC207 **DIODES, ...
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LTC4252-1/LTC4252-2 LTC4252A-1/LTC4252A-2 APPLICATIONS INFORMATION –48RTN DIODE-OR CIRCUIT FOR CHANNEL A –48V A R IN2 3 × 1.8k IN SERIES 1/4W EACH C IN2 1μF FDV301N DIODE-OR CIRCUIT FOR CHANNEL B –48V B R IN3 3 × 1.8k IN SERIES 1/4W ...
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APPLICATIONS INFORMATION The internal fault latches of the LTC4252 are disabled as the TIMER pin is always held low by the SS voltage when Q2 and Q3 are in analog current limit. If both power supplies from channel A and ...
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LTC4252-1/LTC4252-2 LTC4252A-1/LTC4252A-2 PACKAGE DESCRIPTION Please refer to http://www.linear.com/designtools/packaging/ 0.889 ± 0.127 (.035 ± .005) 5.23 3.20 – 3.45 (.206) (.126 – .136) MIN 0.42 ± 0.038 0.65 (.0165 ± .0015) (.0256) TYP BSC RECOMMENDED SOLDER PAD LAYOUT NOTE: 1. DIMENSIONS ...
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REVISION HISTORY (Revision history begins at Rev C) REV DATE DESCRIPTION C 2/11 Revised Typical Application drawings Revised Figures 19, 20, 21, 22 and 23 Replaced Shunt Regulator section in Applications Information D 3/12 Not recommended for ...
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