ltc1778-1 Linear Technology Corporation, ltc1778-1 Datasheet
ltc1778-1
Related parts for ltc1778-1
ltc1778-1 Summary of contents
Page 1
... Extremely Fast Transient Response ■ Stable with Ceramic C OUT ■ Dual N-Channel MOSFET Synchronous Drive ■ Power Good Output Voltage Monitor (LTC1778) ■ Adjustable On-Time (LTC1778-1) ■ Wide V Range 36V IN ■ ±1% 0.8V Voltage Reference ■ Adjustable Current Limit ■ ...
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... I = 1.2V (Note 0.5V to 1.9V (Note 0. 1.2V (Note 0.8V FCB I = 30µ (LTC1778- 15µ (LTC1778- 180µ EXTV Peak Currents .................... EXTV RMS Currents .............. 50mA CC CC ORDER PART TOP VIEW NUMBER 16 BOOST 15 TG LTC1778EGN ...
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... Specifications over the –40°C to 85°C operating temperature range are assured by design, characterization and correlation with statistical and power A process controls. The LTC1778I is guaranteed over the full – 40°C to 125°C operating temperature range. to achieve FB LTC1778/LTC1778-1 MIN TYP MAX UNITS 250 400 ● ...
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... LTC1778/LTC1778 TYPICAL PERFOR A CE CHARACTERISTICS Transient Response V OUT 50mV/DIV I L 5A/DIV 20µs/DIV 1778 G01 LOAD STEP 0A TO 10A V = 15V 2.5V OUT FCB = 0V FIGURE 9 CIRCUIT Efficiency vs Load Current 100 DISCONTINUOUS 90 MODE 80 CONTINUOUS MODE 10V 2.5V OUT EXTV = 5V CC FIGURE 9 CIRCUIT 50 0 ...
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... Maximum Current Sense Threshold vs Temperature 150 RNG 140 130 120 110 100 50 125 –50 – 100 TEMPERATURE (°C) 1778 G11 LTC1778/LTC1778-1 On-Time vs V Voltage ON 1000 I = 30µA ION 800 600 400 200 VOLTAGE (V) ON 1778 G21 Maximum Current Sense ...
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... LTC1778/LTC1778 TYPICAL PERFOR A CE CHARACTERISTICS Error Amplifier g vs Temperature m 2.0 1.8 1.6 1.4 1.2 1.0 –50 – 100 125 TEMPERATURE (°C) 1778 G13 EXTV Switch Resistance CC vs Temperature –50 – 125 100 TEMPERATURE (°C) 1778 G14 RUN/SS Latchoff Thresholds vs Temperature 5 ...
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... PGOOD (Pin 2, LTC1778): Power Good Output. Open drain logic output that is pulled to ground when the output voltage is not within ±7.5% of the regulation point. V (Pin 2, LTC1778-1): On-Time Voltage Input. Voltage ON trip point for the on-time comparator. Tying this pin to the output voltage or an external resistive divider from the output makes the on-time proportional to V comparator input defaults to 0 ...
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... I ION S Q 20k + + I I CMP – – 1.4V V RNG 3 × 0.7V 3.3µA 1 240k THB 0.8V – EA ×4 + – 5 0.8V * LTC1778 ** LTC1778 FCB 9 EXTV CC 4.7V + – 1µA 0.8V + – F FCNT ON SWITCH REV LOGIC SHDN RUN SS SHDN – + 0.6V C RUN/ 0. ...
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... INTV 7V can be applied to EXTV the input voltage is low and INTV undervoltage lockout circuitry prevents the power switches from turning on. LTC1778/LTC1778-1 drops, the buffered current FB is pulled down by clamp When this voltage SS ...
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... ESR to meet the output voltage ripple and transient specification. Choosing the LTC1778 or LTC1778-1 The LTC1778 has an open-drain PGOOD output that indicates when the output voltage is within ±7.5% of the regulation point. The LTC1778-1 trades the PGOOD pin for a V pin that allows the on-time to be adjusted. Tying the ON V ...
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... R . Figures 3a and 3b show how R ON switching frequency for several common output voltages. R DS(ON)(MAX) R DS(ON)(MAX) –1 can Figure 3a. Switching Frequency vs R for the LTC1778 and LTC1778 LTC1778/LTC1778-1 from V to the I pin yields an on For a step-down con ...
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... LTC1778/LTC1778 APPLICATIO S I FOR ATIO Because the voltage at the I pin is about 0.7V, the ON current into this pin is not exactly inversely proportional especially in applications with lower input voltages correct for this error, an additional resistor R connected from the I pin to the 5V INTV ON further stabilize the frequency ...
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... ESR in the range of 0.5Ω to 2Ω. High performance through-hole capacitors may also be used, Kool Mµ registered trademark of Magnetics, Inc. LTC1778/LTC1778 This simple worst-case condition is is primarily determined by the ESR ...
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... LTC1778/LTC1778 APPLICATIO S I FOR ATIO but an additional ceramic capacitor in parallel is recom- mended to reduce the effect of their lead inductance. Top MOSFET Driver Supply ( external bootstrap capacitor C connected to the BOOST B pin supplies the gate drive voltage for the topside MOSFET. ...
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... As the RUN/SS voltage rises to 3V, the clamp raised until its full 2.4V range is available. This takes an additional 1.3s/µF, during which the load current is folded back until the output reaches 75% of its final value. The pin can be driven from logic as shown in Figure 7. Diode D1 LTC1778/LTC1778-1 voltage of about 6V. CC BOOST INTV ...
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... LTC1778/LTC1778 APPLICATIO S I FOR ATIO reduces the start delay while allowing C slowly for the soft-start function. After the controller has been started and given adequate time to charge up the output capacitor, C short-circuit timer. After the RUN/SS pin charges above 4V, if the output voltage falls below 75% of its regulated value, then a short-circuit fault is assumed. A 1.8µ ...
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... J ⎞ ⎟ = µ The junction temperatures will be significantly less at V ⎠ nominal current, but this analysis shows that careful attention to heat sinking will be necessary in this circuit. LTC1778/LTC1778-1 ⎛ ⎞ – ⎟ = ⎜ ...
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... LTC1778/LTC1778 APPLICATIO S I FOR ATIO C is chosen for an RMS current rating of about 85°C. The output capacitors are chosen for a low ESR of 0.013Ω to minimize output voltage changes due to induc- tor ripple current and load steps. The ripple voltage will be only: = ∆ ...
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... SW RNG 13 PGND VCC 11 INTV EXTV FB CC Figure 10. LTC1778 Layout Diagram LTC1778/LTC1778-1 close to the power IN decoupling capacitor C CC and PGND pins. CC closely to the B pin decoupling capacitor C IN and PGND pins – – V ...
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... LTC1778/LTC1778-1 U TYPICAL APPLICATIO 0.1µF 1 RUN/ 100k 11k 39k 2 PGOOD 3 V RNG 4 FCB 680pF C 20k 100pF 6 SGND 10k 576k R2 8.87k C : MURATA GRM42-2X5R226K6.3 IN1 CORNELL DUBILIER ESRE271M02B OUT C SS 0.1µ 100k ...
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... SGND INTV 1Ω 0.1µF V EXTV FB CC (619) 661-6835 (847) 956-0667 (408) 822-2126 (805) 446-4800 LTC1778/LTC1778 OUT 18V 6A 12V 18V C IN 22µF D2 50V IR 12CWQ03FN ×2 V OUT 12V C + OUT 100µF ...
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... LTC1778/LTC1778-1 U TYPICAL APPLICATIO 0.1µF LTC1778-1 1 RUN/ RNG 4 FCB 4700pF C 10k 100pF 6 SGND 10k 698k 52. TAIYO YUDEN TMK432BJ106MM IN1 C : SANYO 35CV10GX IN2 C : PANASONIC EEFUD0J101R OUT L1: PANASONIC ETQPAF2R7H 22 Positive-to-Negative Converter, –5V/5A at 300kHz ...
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... TYP .008 – .012 (0.203 – 0.305) TYP LTC1778/LTC1778-1 .189 – .196* (4.801 – 4.978) .009 (0.229 REF .150 – .157** (3.810 – 3.988) ...
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... LTC1778/LTC1778-1 U TYPICAL APPLICATIO C SS 0.1µ 100k 470pF C 33k C C2 100pF R1 11. 220k R2 C2 24.9k 2200pF C : TAIYO YUDEN TMK432BJ106MM CORNELL DUBILIER ESRD121M04B OUT L1: TOKO A921CY-1R0M RELATED PARTS PART NUMBER DESCRIPTION LTC1622 550kHz Step-Down Controller LTC1625/LTC1775 No R Current Mode Synchronous Step-Down Controller ...