LX1552 Microsemi Corporation, LX1552 Datasheet
LX1552
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LX1552 Summary of contents
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... LX155xIM -55 to 125 — Note: All surface-mount packages are available in Tape & Reel. Append the letter "T" to part number. (i.e. LX1552CDMT 11861 W Copyright © 1994 Rev ...
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... LX1552/3/4 Supply Voltage (Low Impedance Source) .................................................................. 30V Supply Voltage (I < 30mA) ......................................................................... Self Limiting CC Output Current ............................................................................................................. ±1A Output Energy (Capacitive Load) ................................................................................ 5µJ Analog Inputs (Pins 2, 3) ...
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... 20mA O Over Line, Load, and Temperature V 10Hz f 10kHz 25° 125° 1000hrs 25° 25° 698 , C = 22nF, LX1552/3 only 25V MIN A MAX V peak to peak PIN 25° PIN 4 ...
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... Parameter measured at trip point of latch with V V COMP 4. Gain defined as ISENSE 5. Adjust V above the start threshold before setting at 15V Output frequency equals oscillator frequency for the LX1552 and LX1553. Output frequency is one half oscillator frequency for the LX1554 and LX1555 34V GROUND** 16V (1552/1554) 8 ...
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... CURRENT SENSE SPIKE SUPPRESSION 31. MOSFET PARASITIC OSCILLATIONS 32. ADJUSTABLE BUFFERED REDUCTION OF CLAMP LEVEL WITH SOFT-START 33. EXTERNAL DUTY CYCLE CLAMP AND MULTI-UNIT SYCHRONIZATION 34. SLOPE COMPENSATION 35. OPEN LOOP LABORATORY FIXTURE 36. OFF-LINE FLYBACK REGULATOR LX1552/3/4/5 -M PWM ODE FIGURE INDEX Theory of Operation Section Typical Applications Section ...
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... LX1552/3/4/5 FIGURE 1. — OSCILLATOR FREQUENCY vs. TIMING RESISTOR 1000 100 C = 6.8nF 22nF 47nF 0.1µ 15V 25°C A 0 Timing Resistor - ( FIGURE 3. — OSCILLATOR DISCHARGE CURRENT vs. ...
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... FIGURE 5. — OUTPUT INITIAL ACCURACY vs. TEMPERATURE 65.0 LX1552 and LX1553 only 63.5 62.0 60.5 59.0 57.5 56.0 54.5 53.0 51.5 50.0 -75 -50 - Ambient Temperature - (°C) A FIGURE 7. — REFERENCE VOLTAGE vs. TEMPERATURE 5.03 5.02 5.01 5.00 4.99 4.98 4.97 4.96 4.95 -75 -50 - Ambient Temperature - (°C) A Copyright © 1994 Rev ...
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... 250 225 200 LX1552/LX1554 175 150 125 100 LX1553/LX1555 -75 -50 - Ambient Temperature - (°C) A 250 LX1552/LX1554 225 T = 25°C A 200 175 150 125 100 Supply Voltage - (V) CC 100 125 ...
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... IN 210 V = 10V IN 180 150 120 1000 FIGURE 16. — START-UP THRESHOLD vs. TEMPERATURE 8.8 8 125°C A 8.6 8.5 8.4 8 -55°C A 8.2 8.1 8.0 7.9 7.8 3.0 3.5 4.0 4.5 5.0 LX1552/3/4/5 -M PWM ODE TEMPERATURE V = 15V PIN3 C = 1nF L -75 -50 - Ambient Temperature - (°C) A LX1553 LX1555 -75 -50 - Ambient Temperature - (°C) ...
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... FIGURE 20. — LOW LEVEL OUTPUT SATURATION VOLTAGE 1.20 LX1553 1.08 LX1555 0.96 0.84 0.72 0.60 0.48 0.36 0.24 0.12 0. 100 125 -M PWM ODE TEMPERATURE LX1552 LX1554 9.8 9.6 9.4 9.2 9.0 -75 -50 - Ambient Temperature - (°C) A DURING UNDER-VOLTAGE LOCKOUT -55° 25° 125°C A 0.1 1 Output Sink Current - (mA) ...
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... FIGURE 22. — OUTPUT SATURATION VOLTAGE vs. 6.00 5.40 4.80 4.20 3.60 3.00 2. -55° 125°C 1.20 A 0.60 0.00 1000 LX1552/3/4/5 -M PWM ODE OUTPUT CURRENT and TEMPERATURE V = 15V CC Source Transistor T = 25° -55° 125° ...
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... LX1552/3/4/5 IC DESCRIPTION The LX1552/3/4/5 series of current mode PWM controller IC's are designed to offer substantial improvements in the areas of start- up current and oscillator accuracy when compared to the first generation products, the UC184x series. While they can be used in most DC-DC applications, they are optimized for single-ended designs such as Flyback and Forward converters ...
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... OSCILLATOR The oscillator circuit is designed such that discharge current and valley voltage are trimmed independently. This results in more accurate initial oscillator frequency and maximum output duty cycle, especially important in LX1552/53 applications. oscillator is programmed by the values selected for the timing components (R ) and (C ) ...
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... Example: A flyback power supply design requires the duty cycle to be limited to less than 45%. If the output switching frequency is selected to be 100kHz, what are the values 100 a) LX1552/53, and the b) LX1554/ LX1552/53 Given 100kHz LX1554/55 ...
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... This allows more efficient usage of the IC at higher frequencies, as well as improving the noise susceptibility of the device. Internal circuitry insures that the outputs are held off during V section, shows output sink saturation voltage vs. current at 5V -55°C A 4.0 4.5 5.0 LX1552/3/4/5 -M PWM ODE value of is given by: F 3(1. 10K ...
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... LX1552/3/4/5 FIGURE 30. — CURRENT SENSE SPIKE SUPPRESSION LX155x The RC low pass filter will eliminate the leading edge current spike caused by parasitics of Power MOSFET. FIGURE 32. — ADJUSTABLE BUFFERED REDUCTION OF CLAMP ...
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... PWM LATCH 5(9) FIGURE 35. — OPEN LOOP LABORATORY FIXTURE R T LX155x 1 COMP V 8 REF 0.1µ OUTPUT 6 SENSE GROUND LX1552/3/4/5 -M PWM ODE (continued BUS CC 7(12) 7(11) Q1 6(10) 5( REF 0.1µF 1K OUTPUT GROUND ...
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... LX1552/3/4 4.7 1W 1N4004 1N4004 AC 1N4004 1N4004 INPUT LX1554 20k V 2 150k COMP 1 3.6k 100pF V 8 10k R 4 0.01µF .0022µF ...