LT1725CGN#TR Linear Technology, LT1725CGN#TR Datasheet
LT1725CGN#TR
Specifications of LT1725CGN#TR
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LT1725CGN#TR Summary of contents
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... Available in 16-Pin SO and SSOP Packages U APPLICATIO S ■ Telecom Isolated Converters ■ Offline Isolated Power Supplies ■ Instrumentation Power Supplies , LTC and LT are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. U TYPICAL APPLICATIO 48V to Isolated 5V Converter LT1725 35.7k BAS16 3V ...
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LT1725 ABSOLUTE AXI U RATI GS (Note 1) V Supply Voltage ................................................. 22V CC UVLO Pin Voltage .................................................... V I Pin Voltage .................................................... 2V SENSE FB Pin Current ..................................................... ±2mA Operating Junction Temperature Range LT1725C .............................................. 0°C ...
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ELECTRICAL CHARACTERISTICS temperature range, otherwise specifications are at T SYMBOL PARAMETER Gate Output V Output High Level GATE Output Low Level I Output Sink Current in Shutdown, V GATE t Rise Time r t Fall Time f Current Amplifier V ...
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LT1725 W U TYPICAL PERFOR A CE CHARACTERISTICS V Turn-On Voltage vs CC Temperature 16.00 15.75 15.50 15.25 15.00 14.75 14.50 14.25 –50 – 100 125 TEMPERATURE (°C) 1725 G01 Supply Current vs Temperature 13 12 ...
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W U TYPICAL PERFOR A CE CHARACTERISTICS Minimum Switch-On Time vs Temperature 275 R = 50k TON 250 225 200 175 150 125 50 100 125 –50 – TEMPERATURE (°C) 1725 G10 Feedback Amplifier Output Current vs ...
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LT1725 CTIO S PGND (Pin 1): The power ground pin carries the GATE node discharge current. This is typically a current spike of several hundred mA with a duration of tens of nanosec- onds. It ...
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CTIO S ENDLY (Pin 13): Pin for external programming resistor to set enable delay time. See Applications Information for details. t (Pin 14): Pin for external programming resistor to set ON switch minimum on time. ...
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LT1725 DIAGRA V SW VOLTAGE V IN GND SWITCH OFF STATE MINIMUM t ON FLYBACK AMP STATE W FLYBACK ERROR A PLIFIER OFF ENABLE DELAY DISABLED MINIMUM ENABLE TIME ...
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U OPERATIO The LT1725 is a current mode switcher controller IC designed specifically for the isolated flyback topology. The Block Diagram shows an overall view of the system. Many of the blocks are similar to those found in traditional designs, ...
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LT1725 U OPERATIO Enable Delay When the output switch shuts off, the flyback pulse appears. However, it takes a finite time until the trans- former primary side voltage waveform approximately rep- resents the output voltage. This is partly due to ...
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U OPERATIO transformer secondary and output capacitor. This has been represented previously by the expression “I ESR.” However generally more useful to convert this expression to an effective output impedance. Because the secondary current only flows during the ...
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LT1725 U U APPLICATIO S I FOR ATIO TRANSFORMER DESIGN CONSIDERATIONS Transformer specification and design is perhaps the most critical part of applying the LT1725 successfully. In addi- tion to the usual list of caveats dealing with high frequency isolated ...
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U U APPLICATIO S I FOR ATIO which reduces the size of the primary-referred flyback pulse used for feedback. This will increase the output voltage target by a similar percentage. Note that unlike leakage spike behavior, this phenomena is load ...
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LT1725 U U APPLICATIO S I FOR ATIO with the new compensation in place. Modify the original R value if necessary to increase or decrease the OCMP effective compensation. SELECTING OSCILLATOR CAPACITOR VALUE The switching frequency of the LT1725 is ...
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U U APPLICATIO S I FOR ATIO to transformer leakage inductance. This spike is not in- dicative of actual output voltage (see Figure 4B). Delaying the enabling of the feedback amplifier allows this system to effectively ignore most or all ...
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LT1725 U U APPLICATIO S I FOR ATIO amplified. If severe enough, this can cause erratic opera- tion. For example, assume 3nH of parasitic inductance (equivalent to about 0.1 inch of wire in free space series with an ...
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U U APPLICATIO S I FOR ATIO UVLO R2 (6a) “Standard” UVLO Divider Topology speed supply ripple, while leaving the UVLO pin node impedance relatively unchanged at high frequency. INTERNAL WIDE HYSTERESIS UNDERVOLTAGE LOCKOUT The LT1725 is ...
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LT1725 U U APPLICATIO S I FOR ATIO Capacitor C1 should then be made large enough to avoid the relaxation oscillatory behavior described above. This is complicated to determine theoretically as it depends on the particulars of the secondary circuit ...
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U U APPLICATIO S I FOR ATIO Output Impedance Error An additional error source is caused by transformer sec- ondary current flow through the real life nonzero imped- ances of the output rectifier, transformer secondary and output capacitor. Because the ...
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LT1725 U U APPLICATIO S I FOR ATIO MAXIMUM LOAD/SHORT-CIRCUIT CONSIDERATIONS The LT1725 is a current mode controller. It uses the V node voltage as an input to a current comparator which turns off the output switch on a cycle-by-cycle ...
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U U APPLICATIO S I FOR ATIO SWITCH NODE CONSIDERATIONS For maximum efficiency, gate drive rise and fall times are made as short as practical. To prevent radiation and high frequency resonance problems, proper layout of the components connected to ...
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LT1725 U TYPICAL APPLICATIO S TELECOM 48V TO ISOLATED 15V APPLICATION The design in Figure 9 accepts an input voltage in the range of 36V to 72V and outputs an isolated 15V 2A. Transformer ...
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U TYPICAL APPLICATIO S Application Regulation 15 48V 36V IN 15 72V IN 14.5 0 0.5 1.0 1.5 I (A) LOAD 48V to Isolated 15V Application Parts List T1: Coiltronics VP5-0155 VERSA-PAK M1: ...
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LT1725 U TYPICAL APPLICATIO S TELECOM 48V TO ISOLATED 5V APPLICATION The design in Figure 10 accepts an input voltage in the range of 36V to 72V and outputs an isolated 2A. Transformer T1 is available ...
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U TYPICAL APPLICATIO S 48V to Isolated 5V Application Parts List T1: Coiltronics CTX02-14989 M1: International Rectifier IRF620. 200V, 0.8Ω N-channel MOSFET D1: International Rectifier 12CWQ06FN. 12A, 60V Schottky diode D2: BAS16. 75V switching diode C1: AVX TPSD156M035R0300. 15µF, 35V ...
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LT1725 PACKAGE DESCRIPTIO .254 MIN .0165 ± .0015 RECOMMENDED SOLDER PAD LAYOUT .007 – .0098 (0.178 – 0.249) .016 – .050 (0.406 – 1.270) NOTE: 1. CONTROLLING DIMENSION: INCHES INCHES 2. DIMENSIONS ARE IN (MILLIMETERS) 3. DRAWING NOT TO SCALE ...
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... MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm) 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 represen- tation that the interconnection of its circuits as described herein will not infringe on existing patent rights. ...
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... Second Output Synchronous Driver Controller Medium Power, High Efficiency Forced Continuous Operation, 250kHz Similar Function to LTC3900, Used in Full-Bridge and Push-Pull Converter www.linear.com ● = 2.7V to 23V IN Range: 4.5V to 12V CC 1725fa LT 1105 REV A • PRINTED IN THE USA © LINEAR TECHNOLOGY CORPORATION 2000 ...