lt1533 Linear Technology Corporation, lt1533 Datasheet
lt1533
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lt1533 Summary of contents
Page 1
... Low minimum supply voltage and low supply current during shutdown make the LT1533 well suited for portable applica- tions. The part may also be forced into a 50% duty cycle mode for unregulated applications. The LT1533 is available in the 16-pin narrow SO package ...
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... SHDN Pin Voltage .................................................... 30V Feedback Pin Current ............................................ 10mA Negative Feedback Pin Current ............................ 10mA Storage Temperature Range ................. – 150 C Maximum Junction Temperature ......................... 125 C Operating Junction Temperature Range LT1533C ............................................... 100 C LT1533I ............................................ – 100 C Lead Temperature (Soldering, 10 sec).................. 300 C ELECTRICAL CHARACTERISTICS 0.9V ...
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... VSL CSL Either 17k VSL CSL Note 2: The LT1533 is designed to operate over the junction temperature range of – 125 C, but is neither tested nor guaranteed beyond 100 C for C grade or – 100 C for I grade. LT1533 MIN TYP MAX ...
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... LT1533 W U TYPICAL PERFORMANCE CHARACTERISTICS Minimum Input Voltage vs Temperature 2.70 2.65 2.60 2.55 2.50 2.45 –50 100 125 150 – JUNCTION TEMPERATURE ( C) 1533 G01 Feedback Voltage and Input Current vs Temperature 1.30 1.29 1.28 1.27 1. 1.25 1.24 1. 1.22 1.21 1.20 –50 – 100 125 150 TEMPERATURE ( C) 1533 G04 Switching Frequency vs Feedback Pin Voltage ...
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... This can be done by trace inductance (approxi- mately 1") or with wire or a specific inductive component. This inductance ensures stability in the current slew control loop during turn-off. Too much inductance (>50nH) may produce oscillation on the output voltage slew edges. LT1533 pin to ground may IN VSL below 2 ...
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... The LT1533 greatly simplifies the task of eliminating supply noise by enabling the design of an inherently low noise switching regulator power supply. The LT1533 is a fixed frequency, current mode switching regulator with unique circuitry to control the voltage and current slew rates of the output switches. Slew control ...
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... V 50% Duty Cycle Mode Since the LT1533 has dual out-of-phase outputs ideal for driving push-pull transformers. For simple DC trans- former applications, the part can be forced into a 50% duty cycle mode using the DUTY pin. Grounding the DUTY pin ...
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... LT1533 U U APPLICATIONS INFORMATION It is beyond the scope of this data sheet to get into EMI fundamentals. AN70 contains much information concern- ing noise in switching regulators and should be consulted. Oscillator Frequency The oscillator determines the switching frequency and therefore the fundamental positioning of all harmonics. ...
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... When both FB and NFB pins are used, the LT1533 will act to prevent either output from going beyond its set output voltage. The highest output (lightest load) will dominate control of the regulator. This technique would prevent either output from going unregulated high at no load ...
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... LT1533 U U APPLICATIONS INFORMATION Thermal Considerations Computing power dissipation for this IC requires careful attention to detail. Reduced output slewing causes the part to dissipate more power than would occur with fast edges. However, much improvement in noise can be produced with modest decrease in supply efficiency. ...
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... The inductor is smaller for discontinuous operation but the peak currents in the switch, the transformer, the diodes, inductor and capacitor will be higher. But for low power situations these may not present a big constraint. LT1533 V V OUT F DC ...
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... LT1533 U U APPLICATIONS INFORMATION For continuous operation the inductor ripple current must be less than twice the output current. The worst case for this is at maximum input (lowest DC) but we will evaluate at nominal input since the somewhat arbitrary. OUT Note when both inputs are off, inductor current splits between outputs and the diode common goes to 0V ...
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... TPS line addresses this issue). OS-CON: Lower impedance than aluminum but only avail- able for 25V or less. Form factor may be a problem. Sometimes their very low ESR can cause loop stability problems. LT1533 NOMINAL OUTPUT VOLTAGE COILTRONICS AFTER LINEAR ...
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... MBR130 (1A/30V). Low output current applications may use 1N4148 switching diodes. Unregulated Applications The LT1533 can be used to create a low noise “DC transformer” unregulated power supply. DC transformers are open-loop switching regulators where the output voltage is controlled by the turns ratio of the transformer. ...
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... U More Help and R VSL CSL AN70 contains much information concerning LT1533 applications and measurement of noise and should be consulted 12V demo board is also available (DC173). AN19 and AN29 also have general knowledge concerning switching regulators. Our Application Depart- ment is always ready to lend a helping hand. ...
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... T1: COILTRONICS CTX02-13665-X1 Output Noise Is Below 100 V. See AN70 for Details 2. 1N4148 100 COL A 1N4148 15 COL PGND LT1533 15k 13 R VSL 15k 12 R CSL 7 FB GND NFB 3.48k L1, L3: COILTRONICS CTX100 L2: 22nH TRACE INDUCTANCE, FERRITE BEAD OR ...
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... R CSL 360 GND NFB 2.49k 9 8 L1: COILTRONICS CTX100-3 1% L2: 22nH TRACE INDUCTANCE, FERRITE BEAD OR INDUCTOR COILCRAFT B-07T TYPICAL Q1, Q2: ZETEX ZTX-853 Q3: 2N2222A T1: CTX02-13665-X1 LT1533 L3 OPTIONAL FOR 12V LOWEST RIPPLE 100 21.5k 1% – 2.32k 1% + 150k 1.18V V INTERNAL ...
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... LT1533 U TYPICAL APPLICATIONS A 10W Low Noise 5V to 12V Converter. Q1-Q2 Provide 5A Output Capacity While Preserving LT1533’s Voltage Current Slew Control. Efficiency Is 68%. Higher Input Voltages Minimize Follower Loss, Boosting Efficiency Above 71 4 FB1 SHDN COL A 3 FB2 DUTY 15 COL B ...
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... Plastic Small Outline (Narrow 0.150) (LTC DWG # 05-08-1610 0.228 – 0.244 (5.791 – 6.197 0.053 – 0.069 (1.346 – 1.752) 0.014 – 0.019 (0.355 – 0.483) LT1533 0.386 – 0.394* (9.804 – 10.008 0.150 – 0.157** (3.810 – 3.988 0.004 – ...
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... Without Filter Components 1. 1.6k 1W 360k 12V IRF840 IRF840 10k 0.002 1N5818 1N5818 COL A COL LT1533 SHDN CSL VSL T HV 22k 3.9k 3300pF 15 F 12V 43k 12V BAT-85 470k + + 1/2 LM393 1/2 LM393 – 4V POWER LIMIT ...