LT3574IMS#PBF Linear Technology, LT3574IMS#PBF Datasheet

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... The output voltage is easily set with two external resistors and the transformer turns ratio. Off-the-shelf transformers are available for many applications. L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks and No R and ThinSOT are trademarks of Linear Technology Corporation. All other SENSE trademarks are the property of their respective owners ...

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... LEAD FREE FINISH TAPE AND REEL LT3574EMS#PBF LT3574EMS#TRPBF LT3574IMS#PBF LT3574IMS#TRPBF Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. For more information on lead free part marking, go to: For more information on tape and reel specifications, go to: ...

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T PARAMETER Error Amplifier Transconductance Minimum Switching Frequency TC Current into R REF BIAS Pin Voltage Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the ...

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LT3574 typical perForMance characteristics Switch Saturation Voltage 300 250 200 25°C 150 125°C –50°C 100 100 200 300 400 500 600 700 800 SWITCH CURRENT (mA) 3574 G04 SHDN/UVLO Falling Threshold 1.28 1.26 1.24 1.22 1.20 1.18 ...

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Functions BIAS: Bias Voltage. This pin supplies current to the switch driver and internal circuitry of the LT3574. This pin must be locally bypassed with a capacitor. This pin may also be connected third winding ...

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LT3574 block DiagraM CURRENT REF R4 BIAS C5 R1 1.22V SHDN/UVLO R2 2.5µ FLYBACK Q2 ERROR CURRENT AMP COMPARATOR – – ...

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The LT3574 is a current mode switching regulator IC designed specifically for the isolated flyback topology. The special problem normally encountered in such cir- cuits is that information relating to the output voltage on the isolated secondary side of ...

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LT3574 applications inForMation ERROR AMPLIFIER—PSEUDO DC THEORY In the Block Diagram, the R (R4) and R REF can be found. They are external resistors used to program the output voltage. The LT3574 operates much the same way as traditional current ...

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ERROR AMPLIFIER—DYNAMIC THEORY Due to the sampling nature of the feedback loop, there are several timing signals and other constraints that are required for proper LT3574 operation. Minimum Current Limit The LT3574 obtains output voltage information from the ...

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LT3574 applications inForMation Table 2. Common Resistor Values for 2:1 Transformers V ( (kΩ) OUT PS FB 3.3 2.00 37 2.00 130 15 2.00 162 Table 3. Common Resistor Values for 3:1 Transformers V ...

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... L10-1022 9.52 × 9.52 × 4.95 Linear Technology has worked with several leading mag- netic component manufacturers to produce pre-designed flyback transformers for use with the LT3574. Table 5 shows the details of several of these transformers. L ...

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LT3574 applications inForMation Turns Ratio Note that when using REF output voltage, the user has relative freedom in selecting a transformer turns ratio to suit a given application. In contrast, simpler ratios of small integers, e.g., ...

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... However, re- member that this will also increase primary-to-secondary capacitance and limit the primary-to-secondary breakdown voltage, so, bifilar winding is not always practical. The Linear Technology applications group is available and extremely qualified to assist in the selection and/or design of the transformer. LT3574 ...

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LT3574 applications inForMation Setting the Current Limit Resistor The maximum current limit can be set by placing a resistor between the R pin and ground. This provides some ILIM flexibility in picking standard off-the-shelf transformers that may be rated for ...

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Overdriving the BIAS Pin with a Third Winding The LT3574 provides excellent output voltage regulation without the need for an opto-coupler, or third winding, but for some applications with higher input voltages (>20V), it may be desirable to ...

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LT3574 applications inForMation BIAS winding turns ratio is selected to program the BIAS voltage to 3~5V. The BIAS voltage shall not exceed the input voltage. The turns ratio is then selected as primary: secondary: BIAS = 3:1:1. 2. Select the ...

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• D Figure 9. RCD Snubber in a Flyback Converter During switch turn-off, the energy stored in the leakage inductance is transferred to the snubber capacitor, and eventually dissipated in the snubber resistor. V ...

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LT3574 typical applications µ F 200k R2 90. 28.7k 10k µ F 200k R2 90. 59k 10k C2 10nF  Low Input Voltage 5V ...

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V IN 12V TO 24V C1 (30V µ F 499k R2 71. 28.7k 10k 5V Isolated Flyback Converter 0.22 µ F 4.02k IN SHDN/UVLO D3 R3 80. LT3574 R ...

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LT3574 typical applications V IN 12V TO 24V C1 (36V µ F 499k R2 71. 19.1k 10k V IN 12V µ F 499k R2 71. 59k 10k C2 10nF 0 3.3V ...

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V IN 12V TO 24V C1 10 µ 499k R2 71. 10k 59k C2 10nF Four Output 12V Isolated Flyback Converter 0.22 µ SHDN/UVLO R3 118k LT3574 ...

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LT3574 typical applications 5V Isolated Flyback Converter Using Coupling Inductor µ F 200k R2 90. 26.1k 10k  C6 0.22 µ SHDN/UVLO R3 26.1k LT3574 REF ...

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... LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights. ...

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... F 7µ • – V OUT – 5V 175mA *OPTIONAL THIRD WINDING FOR >24V OPERATION µ H D1, D2: B340A D4: PMEG6010 T1: W Ü RTH ELEKTRONIK 750310564 3574 TA11 ≤ 36V, Burst Mode ® 0110 • PRINTED IN USA  LINEAR TECHNOLOGY CORPORATION 2010 Operation at 3574f ...