LT1943EFE Linear Technology, LT1943EFE Datasheet
LT1943EFE
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LT1943EFE Summary of contents
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... Available in Thermally Enhanced 28-Lead TSSOP U APPLICATIO S ■ Large TFT-LCD Desktop Monitors ■ Flat Panel Televisions , LTC and LT are registered trademarks of Linear Technology Corporation. PanelProtect is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. U TYPICAL APPLICATIO 20V ...
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... RUN-SS = SS-234 = 0V RUN-SS, SS-234 = 0.4V BIAS = 3.1V, All Switches Off (Note 3) All FB Pins = 1.5V All FB Pins = 1.5V V Current = 30mA 30V 36V PGOOD All FB Pins = 0V ∆200kHz ORDER PART NUMBER 28 SW2 27 SW2 LT1943EFE PGOOD 22 BIAS 21 SW3 20 GND 19 SW4 FE PART MARKING 18 RUN-SS SS-234 17 1943E V ...
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ELECTRICAL CHARACTERISTICS temperature range, otherwise specifications are at T PARAMETER SWITCH 1 (2.4A BUCK) FB1 Voltage FB1 Voltage Line Regulation FB1 Pin Bias Current Error Amplifier 1 Voltage Gain Error Amplifier 1 Transconductance Switch 1 Current Limit Switch 1 V ...
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LT1943 ELECTRICAL CHARACTERISTICS temperature range, otherwise specifications are at T PARAMETER SWITCH 4 (350mA INVERTER) FB4 Voltage FB4 Voltage Line Regulation FB4 Pin Bias Current NFB4 Voltage ( FB4 NFB4 NFB4 Voltage Line Regulation NFB4 Pin Bias Current ...
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W U TYPICAL PERFOR A CE CHARACTERISTICS MINIMUM Input Voltage to Start 3.3V LOGIC 6 25°C A 5.5 5.0 4.5 4.0 3.5 3 100 LOAD CURRENT (mA) 1943 G04 SW3 Current ...
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LT1943 W U TYPICAL PERFOR A CE CHARACTERISTICS V Current Limit ON 100 T = 25° (V) ON 1943 G13 Reference Voltage 1.27 ...
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CTIO S GND (Pins 1, 20, Exposed Pad Pin 29): Ground. Tie both GND pins and the exposed pad directly to a local ground plane. The ground metal to the exposed pad should be as ...
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LT1943 CTIO S SW3 (Pin 21): This is the collector of the internal NPN bipolar power transistor for switching regulator 3. Mini- mize metal trace area at this pin to keep EMI down. BIAS (Pin ...
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W BLOCK DIAGRA MASTER OSCILLATOR V LOGIC 1.2MHz R2 FB1 4 R1 PGOOD – R14 + 1.12V R6 FB2 5 R5 20µ – – – – ...
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LT1943 U OPERATIO The LT1943 is a highly integrated power supply IC con- taining four separate switching regulators. All four switch- ing regulators have their own oscillator with frequency foldback and use current mode control. Switching regula- tor 1 consists ...
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U OPERATIO The control loop for the four switchers is similar. A pulse from the slave oscillator sets the RS latch and turns on the internal NPN bipolar power switch. Current in the switch and the external inductor begins to ...
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LT1943 U OPERATIO maximum load current. For details of maximum output current and discontinuous mode operation, see Linear Technology’s Application Note AN44. Finally, for duty cycles greater than 50 OUT IN inductance is required to avoid subharmonic oscillations. ...
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U OPERATIO Output Capacitor Selection For 5V and 3.3V outputs, a 10µF 6.3V ceramic capacitor (X5R or X7R) at the output results in very low output voltage ripple and good transient response. Other types and values will also work; the ...
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LT1943 U OPERATIO Table 3. Schottky Diodes Part Number V ( (mV) R AVE F On Semiconductor MBRM120E 20 1 MBRM140 40 1 Diodes Inc. B120 20 1 B130 30 1 B220 20 2 B230 ...
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U OPERATIO | OUT OUT The LT1943 can still be used in applications where the duty cycle, as calculated above, is above the maximum. How- ever, the part must be ...
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LT1943 U OPERATIO must have low impedance at the switching frequency to do this effectively and it must have an adequate ripple current rating. The input capacitor RMS current can be calculated from the step-down output voltage and current, and ...
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U OPERATIO should be 5Ω of resistance between the V connection to the load, as shown on Figure 3. The resis- tance will damp resonant tank circuit created by the output short. As the transient on the V pin during ...
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LT1943 U OPERATIO PLACE VIAS UNDER GROUND PAD TO GROUND PLANE FOR GOOD THERMAL CONDUCTIVITY U TYPICAL APPLICATIO S ZHCS400 V OFF –5.5V 50mA 44.2k 2.2µF ZHCS400 10V X5R 10.0k 10pF CMDSH-3 4.7µH 16.2k V LOGIC 3.3V 2A 10.0k 22µF ...
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... MILLIMETERS (INCHES) 3. DRAWING NOT TO SCALE 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 Package 28-Lead Plastic TSSOP (4 ...
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... TFT-LCD Triple Output Switching Regulator LT3464 85mA (I ), Constant Off-Time, High Efficiency Step-Up DC/ Converter with Integrated Schottky and Output Disconnect PNP ThinSOT Package ThinSOT is a trademark of Linear Technology Corporation. Linear Technology Corporation 20 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 ● ...