MAX1747 Maxim Integrated Products, MAX1747 Datasheet
MAX1747
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MAX1747 Summary of contents
Page 1
... The constant switching frequency and a proprietary regulation algorithm minimize output ripple and capaci- tor sizes for all three charge pumps. The MAX1747 is available in the ultra-thin TSSOP package (1.1mm max height). TFT Active-Matrix LCDs ...
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Triple Charge-Pump TFT LCD DC-DC Converter ABSOLUTE MAXIMUM RATINGS IN, SUPM, OUT, TGND to GND................................-0.3V to +6V SHDN........................................................................-0.3V to +1V PGND to GND.....................................................................±0.3V SUPM to IN .........................................................................±0.3V CXN to PGND.........................................-0. CXP to PGND ............................(V - 0.3V ...
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ELECTRICAL CHARACTERISTICS (continued +3.0V SUPM SUPP SUPN 1500pF +5V 0°C to +85°C, unless otherwise noted. Typical values are at T OUT A PARAMETER SYMBOL FBN Input Bias Current ...
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Triple Charge-Pump TFT LCD DC-DC Converter ELECTRICAL CHARACTERISTICS ( +3.0V SUPM SUPP SUPN 1500pF +5V -40°C to +85°C, unless otherwise noted.) (Note 1) OUT A PARAMETER SYMBOL Input ...
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ELECTRICAL CHARACTERISTICS (continued +3.0V SUPM SUPP SUPM 1500pF +5V -40°C to +85°C, unless otherwise noted.) (Note 1) OUT A PARAMETER SYMBOL REFERENCE Reference Voltage V Reference Undervoltage ...
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Triple Charge-Pump TFT LCD DC-DC Converter (Circuit of Figure +3.3V SUPM NO-LOAD SUPPLY CURRENT vs. SWITCHING FREQUENCY 0.5 1.0 1.5 2.0 FREQUENCY (MHz) ...
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... INTG STARTUP WAVEFORM (NO LOAD) MAX1747 toc16 1ms/div V = 5V, NO LOAD OUT ON CONNECTED TO SHDN THROUGH A 58kΩ RESISTOR POWER-UP SEQUENCE MAX1747 toc18 -10V 10V 0 2ms/div -7V 12V MAIN NEG POS ON CONNECTED TO SHDN THROUGH A 58kΩ RESISTOR ...
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... OUT is shut down. Detailed Description The MAX1747 is an efficient triple-output power supply for TFT LCD applications. The device contains one high-power charge pump and two low-power charge pumps. The MAX1747 charge pumps switch continu- ously at a constant frequency, so the output noise con- ...
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... A proprietary regulation algorithm minimizes output rip- ple as well as capacitor sizes for all three charge pumps. Also included in the MAX1747 are a precision 1.25V reference that sources up to 50µA, shutdown, power-up sequencing, fault detection, and an active- low open-drain ready output. ...
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... until the diode (D2) SUPP turns off. Frequency Selection and Shutdown The shutdown pin (SHDN) on the MAX1747 performs a dual function: it shuts down the device and determines the oscillator frequency. The SHDN input looks like a diode to ground and should be driven through a resis- tor (Figure 5) ...
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... Fault Detection 0.22µF bypass capacitor between REF and GND. During shutdown, the reference is disabled. The efficiency characteristics of the MAX1747 regulat- ed charge pumps are similar to a linear regulator. They are dominated by quiescent current at low output cur- rents and by the input voltage at higher output currents (see Typical Operating Characteristics) ...
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... Use Schottky diodes with a current rating greater than 4 times the average output current, and with a voltage rating of 1.5 times V and V SUPN The MAX1747 contains an internal current integrator , which destabi- ON that improves the DC load regulation but increases the peak-to-peak transient voltage (see Load-Transient Waveform in the Typical Operating Characteristics) ...
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... IC’s power ground pin directly to it. Avoid having sensitive traces near the switching nodes and high-current lines. Refer to the MAX1747 evaluation kit for an example of proper board layout. TRANSISTOR COUNT: 2534 Printed USA is a registered trademark of Maxim Integrated Products ...