MAX8728ETJ+ Maxim Integrated Products, MAX8728ETJ+ Datasheet

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... TQFN package and operates over the -40°C to +85°C temperature range. LCD Monitors LCD TVs Ordering Information PIN- PART TEMP RANGE PACKAGE 32 TQFN-EP* MAX8728ETJ+ -40°C to +85°C 5mm x 5mm +Denotes lead-free package. *EP = Exposed pad. Pin Configuration TOP VIEW ...

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Low-Cost, Multiple-Output Power Supply for LCD Monitors/TVs ABSOLUTE MAXIMUM RATINGS IN, INL, SUPP to GND ............................................-0.3V to +14V SUPP to IN ..........................................................................±0.3V DRVP to GNDP.........................................-0. SUPP + 0.3V SHDN, OUT1 GND ................-0.3V ...

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Power Supply for LCD Monitors/TVs ELECTRICAL CHARACTERISTICS (continued) (Circuit of Figure INL SUPP to +85°C. Typical values are +25°C, unless otherwise noted.) A PARAMETER STEP-DOWN REGULATOR V IN OUT1 Voltage ...

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Low-Cost, Multiple-Output Power Supply for LCD Monitors/TVs ELECTRICAL CHARACTERISTICS (continued) (Circuit of Figure INL SUPP to +85°C. Typical values are +25°C, unless otherwise noted.) A PARAMETER Current-Sense Transresistance LX2 On-Resistance ...

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Power Supply for LCD Monitors/TVs ELECTRICAL CHARACTERISTICS (continued) (Circuit of Figure INL SUPP to +85°C. Typical values are +25°C, unless otherwise noted.) A PARAMETER DEL, EN Discharge Switch SHDN = ...

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Low-Cost, Multiple-Output Power Supply for LCD Monitors/TVs ELECTRICAL CHARACTERISTICS (Circuit of Figure INL SUPP -40°C to +85°C.) (Note 2) PARAMETER GENERAL IN, INL Input Voltage Range For VL regulator operation = 7V to ...

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Power Supply for LCD Monitors/TVs ELECTRICAL CHARACTERISTICS (continued) (Circuit of Figure INL SUPP -40°C to +85°C.) (Note 2) PARAMETER CHARGE-PUMP REGULATORS FBP Regulation Voltage FBN Regulation Voltage V REF SEQUENCE CONTROL SHDN Input ...

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Low-Cost, Multiple-Output Power Supply for LCD Monitors/TVs (Circuit of Figure INL SUPP unless otherwise noted.) STEP-DOWN REGULATOR EFFICIENCY vs. LOAD CURRENT GND ...

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Power Supply for LCD Monitors/TVs (Circuit of Figure INL SUPP unless otherwise noted.) STEP-UP REGULATOR SOFT-START (HEAVY LOAD) GATE, 5V/div AV , 5V/div DD 1ms/div STEP-UP REGULATOR PULSED-LOAD TRANSIENT RESPONSE (100mA TO 1A) ...

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Low-Cost, Multiple-Output Power Supply for LCD Monitors/TVs (Circuit of Figure 12V INL SUPP unless otherwise noted.) REF VOLTAGE vs. REF CURRENT 2.000 1.999 1.998 1.997 1.996 1.995 1.994 ...

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Power Supply for LCD Monitors/TVs (Circuit of Figure INL SUPP unless otherwise noted.) NEGATIVE CHARGE-PUMP LOAD TRANSIENT RESPONSE 40µs/div INL SUPPLY CURRENT vs. INL VOLTAGE GND ...

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Low-Cost, Multiple-Output Power Supply for LCD Monitors/TVs PIN NAME 1 GND1 Step-Down Regulator and Negative Charge-Pump Power Ground Step-Down Regulator Output Sense Input. OUT1 is the inverting input to the internal current-sense amplifier. 2 OUT1 Connect OUT1 directly to the ...

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Power Supply for LCD Monitors/TVs PIN NAME High-Voltage Switch Control Input. DRN is the drain of the internal high-voltage p-channel MOSFET connected 21 DRN to GON. See the High-Voltage Switch Control section for details. GON Falling Regulation Adjustment Input. Connect ...

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Low-Cost, Multiple-Output Power Supply for LCD Monitors/TVs V IN 10.8V TO 13.2V C7 1µ BST 10µF C8 16V 0.1µF OUT1 L2 3.3V/2A 2.6µH 6 LX1 C9 D2 22µF 1 6.3V GND1 R11 ...

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Power Supply for LCD Monitors/TVs Typical Operating Circuit The typical operating circuit (Figure 1) of the MAX8728 is a complete power-supply system for TFT LCD panels in monitors and TVs. The circuit generates a +3.3V logic supply, a +13.5V source ...

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Low-Cost, Multiple-Output Power Supply for LCD Monitors/TVs BST IN OUT1 LX1 GND1 OUT1 FB1 FSEL OSCILLATOR REF REFERENCE GND FBN NEGATIVE REGULATOR DRVN V GOFF Figure 2. Functional Diagram 16 ...

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Power Supply for LCD Monitors/TVs Current Limiting and Lossless Current Sensing The current-limit circuit turns off the high-side MOSFET switch whenever the voltage across the high-side MOSFET exceeds an internal threshold corresponding to the actual current limit of 2.8A ±10%. ...

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Low-Cost, Multiple-Output Power Supply for LCD Monitors/TVs The soft-start feature effectively limits the inrush current during startup (see the Step-Down Regulator Soft-Start (Heavy Load) waveforms in the Typical Operating Characteristics). The MAX8728 monitors FB2 for under- voltage conditions. If the ...

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Power Supply for LCD Monitors/TVs Negative Charge-Pump Regulator The negative charge-pump regulator is typically used to generate the negative supply rail for the TFT LCD gate- driver ICs. The output voltage is set with an external resistive voltage-divider from its ...

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Low-Cost, Multiple-Output Power Supply for LCD Monitors/TVs turns off and Q2 turns on, connecting GON to DRN. GON can then be discharged through a resistor con- nected between DRN and GND or AV and stops discharging GON when V times ...

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Power Supply for LCD Monitors/TVs REF DEL Q4 0 REF 50µA REF R 4R MODE 5R 1kΩ Q3 CTL Figure 5. Switch-Control Functional Diagram ______________________________________________________________________________________ Low-Cost, Multiple-Output SWITCH CONTROL 5µA FAULT SHDN EN GATE DONE 9R 1kΩ R ...

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Low-Cost, Multiple-Output Power Supply for LCD Monitors/TVs Fault Protection During steady-state operation, if any output of the four regulators (step-down regulator, step-up regulator, positive charge-pump regulator, and negative charge- pump regulator) does not exceed its respective fault- detection threshold, the ...

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Power Supply for LCD Monitors/TVs Output-Capacitor Selection Since the MAX8728’s step-down regulator is internally compensated stable with any reasonable amount of output capacitance. However, the actual capaci- tance and equivalent series resistance (ESR) affect the regulator’s output ripple ...

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Low-Cost, Multiple-Output Power Supply for LCD Monitors/TVs rent ripple and therefore reduce the peak current, which decreases core losses in the inductor and I losses in the entire power path. However, large induc- tor values also require more energy storage ...

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Power Supply for LCD Monitors/TVs output voltage ripple is typically dominated The voltage rating and temperature AVDD RIPPLE(C) characteristics of the output capacitor must also be considered. Input-Capacitor Selection The input capacitor reduces the current peaks ...

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Low-Cost, Multiple-Output Power Supply for LCD Monitors/TVs Charge-Pump Output Capacitor Decreasing the flying capacitance reduces the output ripple. Increasing the output capacitance reduces the output ripple and improves the transient response. Use the following equations to approximate the output ripple: ...

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Power Supply for LCD Monitors/TVs 3) Place all feedback voltage-divider resistors as close to their respective feedback pins as possible. The divider’s center trace should be kept short. Placing the resistors far away causes their FB traces to become antennas ...

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Low-Cost, Multiple-Output Power Supply for LCD Monitors/TVs (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information www.maxim-ic.com/packages.) 28 ______________________________________________________________________________________ Package Information ...

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... Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 29 © 2006 Maxim Integrated Products ...