LT1248 LINER [Linear Technology], LT1248 Datasheet
LT1248
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LT1248 Summary of contents
Page 1
... The LT1248 uses a multiplier containing a square gain function from the voltage amplifier to reduce the AC gain at light output load and thus maintains low line current distortion and high system stability. The LT1248 also provides filtering capability to reject line switching noise which can cause instability when fed into the multiplier ...
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... EN/SYNC, OVP Input Voltage ................... V SENSE Input Current .................................. 5mA SENSE OUT Operating Junction Temperature Range LT1248C ................................................ 100 C LT1248I ........................................... – 125 C Thermal Resistance (Junction-to-Ambient) N Package .................................................. 100 C/W S Package ................................................... 120 C/W Storage Temperature Range ..................– 150 C Lead Temperature (Soldering, 10 sec)................. 300 C ELECTRICAL C HARA TERISTICS C ...
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... OUT 0.035 100 115 4.35 4.7 5.0 1.25 1.4 1.55 4.5 5.6 6.5 1.2 1.6 1.04 1.05 1.06 0.35 – 50 – 250 100 12 15 17.5 V – 3.0 CC 0.9 1.5 0.5 1 0.2 0 LT1248 UNITS – kHz kHz NOM ...
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... LT1248 W U TYPICAL PERFOR A Voltage Amplifier Open-Loop Gain and Phase 100 80 GAIN PHASE 0 – 10k 100k 100 FREQUENCY (Hz) Reference Voltage vs Temperature 7.536 7.524 7.512 7.500 7.488 7.476 7.464 7.452 7.440 7.428 –75 –50 – JUNCTION TEMPERATURE ( C) Supply Current vs Supply Voltage ...
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... T = – – –12 – 125 C J –8 –6 –4 – VOLTAGE (V) LT1248 Frequency vs R and C SET 500 450 400 350 300 250 200 150 100 200 600 1000 1400 C CAPACITANCE (pF) ...
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... Pulses at this pin that go below the 5V threshold will synchronize the chip. The synchronizing pulses should have an on-time of at least 200ns for the LT1248 resetting circuit to work. Pin 11 (V SENSE amplifier. ...
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... With a square function, because of the lower gain at light power load, system stability is maintained and line current distortion caused by the line frequency AC may need OUT Figure 1. Multiplier Current I ): This is the supply for the chip. The LT1248 • I )/(200 A) ...
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... SET /R . Synchronization REF SET = 1nF is 250ns. R SET The LT1248 can be synchronized to a frequency that 1.6 times the natural frequency. With a 200ns one-shot timer on-chip, the LT1248 provides flexibility on the = 3.75V/15k M(MAX) synchronizing pulse width. Because the EN/SYNC pin also to the 0.2 OUT ...
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... In the lockout state, the LT1248 only draws 250 A, the oscillator is off, and the V the GTDR pins remain low to keep the power MOSFET off. Start-Up and Supply Voltage The LT1248 draws only 250 A before the chip starts at 16V on V line while switching starts ...
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... For V = 382V, V OUT 1000pF, and f = 100kHz, Zener current will be 36mA. This is enough to operate the LT1248, including the FET gate drive. Normally soft-start is not needed because the LT1248 has overcurrent limit and overvoltage protection. If soft-start is used with a 0.01 F capacitor on SS pin, V ramps up slower during start-up ...
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... 200 A – B 32k + + 0.7V – ONE SHOT 200ns SYNC C SET 14 1000pF ® 77930 CORE) GENERATOR. CC Kool registered trademark of Magnetics, Inc. LT1248 MURH860 750 H* 1M IRF840 1% 20k 18V 35V PK V GND LIM – GTDR ...
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... LT1248 PACKAGE DESCRIPTIO 0.300 – 0.325 0.130 0.005 (7.620 – 8.255) (3.302 0.127) 0.020 (0.508) MIN 0.009 – 0.015 (0.229 – 0.381) +0.035 0.325 –0.015 0.125 +0.889 (3.175) 8.255 –0.381 MIN *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm) 0.010 – ...