AAT2856 AAT, AAT2856 Datasheet
AAT2856
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AAT2856 Summary of contents
Page 1
... The AAT2856 is equipped with built-in short-circuit and over-temperature protection. The soft start cir- cuitry prevents excessive inrush current at start-up and mode transitions. The AAT2856 is available in a Pb-free TQFN44-28 package and operates over the -40°C to +85°C ambient temperature range. Typical Application ...
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... Negative node of charge pump capacitor 2. Connect the 1µF charge pump capacitor 2 from C2+ to C2-. 19 PGND Power ground. Connect AGND to PGND at a single point as close to the AAT2856 as pos- sible. 20 ENS Backlight enable and serial control input. ENS turns the backlight on/off and is the ...
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... Pin Configuration 2856.2007.06.1.0 High Current Charge Pump with Dual LDO for BacklightApplications TQFN44-28 (Top View BL3 OUT 1 21 BL2 ENS 2 20 BL1 PGND 3 19 AGND AGND C2 REF C2 FBB ENB AAT2856 3 ...
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... Only one Absolute Maximum Rating should be applied at any one time. 2. Mounted on a FR4 circuit board. 3. Derate 6.25 mW/°C above 25°C ambient temperature. 4 High Current Charge Pump with Dual LDO for BacklightApplications 1 3 AAT2856 Value Units -0.3 to 6 0.3 V OUT -0 ...
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... ENS(LAT) Timeout 1. The AAT2856 is guaranteed to meet performance specifications over the -40°C to +85°C operating temperature range and is assured by design, characterization, and correlation with statistical process controls. 2. Current matching is defined as the deviation of any sink current from the average of all active channels. 2856.2007.06.1.0 ...
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... EN _ (H) t ENA, ENB Enable Delay EN _ (DLY) 1. The AAT2856 is guaranteed to meet performance specifications over the -40°C to +85°C operating temperature range and is assured by design, characterization, and correlation with statistical process controls. 6 High Current Charge Pump with Dual LDO for BacklightApplications ...
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... V OUT (2V/div) V SINK (500mV/div (200mA/div) = 2.7V (2V/div) V OUT (2V/div (200mA/div) AAT2856 (20mA/Ch; Data 1) - Temperature (°C) Turn On to 1.5X Mode Backlight (30mA/ch; Data 3.4V Time (200µs/div) Turn Off from 1.5X Mode Backlight (30mA/ch; Data Time (100µ ...
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... BENS, FENS Off Timeout vs. Input Voltage 300 260 25°C 220 180 25°C 140 100 2.7 4.7 5.1 5.5 1.0 0.5 0.0 -0.5 -1.0 0.1 AAT2856 BENS, FENS Low Threshold Voltage vs. Input Voltage -40°C 85°C 25°C 3.1 3.5 3.9 4.3 4.7 Input Voltage (V) 25°C -40°C 85°C 3.1 3.5 3.9 4.3 4.7 Input Voltage (V) LDOs A and B Load Regulation OUTA OUTB 1 10 100 Load Current (mA) 2856 ...
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... High Current Charge Pump with Dual LDO for BacklightApplications 1.5 1 OUTA 0.5 0 OUTB -0.5 -1 -1.5 -40 4.7 5.1 5.5 (250mV/div) V (AC Coupled) (20mV/div) 3.1 3.2 = 200mA AAT2856 LDOs A and B Output Voltage vs. Temperature - Temperature (°C) LDOs A and B Line Transient Response (10mA Load 3. 3.1V IN OUT Time (50µs/div ...
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... ENA ENB ENS Functional Description The AAT2856 is a highly integrated backlight LED driver with two LDO linear regulators. The charge pump LED driver drives backlight LEDs from a 2.7V to 5.5V input voltage. The LDO regulators are operated from the same input voltage range and produce regulated output voltages as low as 1 ...
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... LED is shorted. In either case, the controller turns off the affected current sink Cwire Serial Interface The AAT2856 is dynamically programmable by the AS 2 Cwire single-wire interface. AS rising edges detected at the ENS pin to address and load the data registers. AS ...
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... Data Code Figure 2: Data Code for Address 0-3 vs. Backlight Current Level. The AAT2856 incorporates additional circuitry that optimizes performance for exceptionally low back- light current settings. A separate address is used to activate this circuitry. To program the low current settings with improved performance and efficiency, write to Address 3 ...
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... To enable independent channel control mode, write Data 8 to Address 15. To exit individual mode con- trol, the AAT2856 state machine can be reset by strobing ENS low and holding ENS low longer than the A 2 SCwire's t latch time ...
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... Low Dropout Regulators The AAT2856 includes two independent LDO linear regulators. The regulators operate from a 2.7V to 5.5V input voltage at IN. The AAT2856 supplies separate LDO enable inputs (ENA and ENB) to control individually the operation of the LDOs. The LDO output voltages are set through resistive volt- age dividers from the output (OUTA or OUTB) to the feedback input (FBA or FBB) ...
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... LEDs particularly suitable for LEDs with an operating forward voltage in the range of 1.5V to 4.2V. The charge pump can also drive other loads that have similar characteristics to white LEDs. For var- ious load types, the AAT2856 provides a high-cur- rent, programmable ideal constant current source. F Capacitor Selection IN ...
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... Y5V dielectric materials. Large ceramic capacitors are often available in lower-cost dielectrics, but capacitors greater than 10µF are not typically required for AAT2856 applications. Capacitor area is another contributor to ESR. Capacitors that are physically larger will have a lower ESR when compared to an equivalent mate- rial smaller capacitor ...
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... Evaluation Board Layout Figure 7: AAT2856 Evaluation Board Layout Top Side. Evaluation Board User Interface The user interface for the AAT2856 evaluation board is provided through 4 buttons and a number of connection terminals. The board is operated by supplying external power and pressing individual buttons or button combinations. The table below indicates the function of each button or button combination ...
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... AGND AGND C2 REF C2 FBB ENB 2.2μF 1.0μF 78. 2.2μF 59k C7 R4 2.2μF 29.4k Programmed for 1.8V output by default R3 59k Figure 9: AAT2856 Section Schematic AAT2856 VOUT C3 2.2μ ENS C4 C2 4.7μF 1.0μF ENB VOUT OUTA 2856.2007.06.1.0 ...
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... OUT3 2 7 OUT2 OUT4 3 6 OUT1 OUT5 4 5 EN/SET GND VIN R10 VDD VSS 2 GP5 GP0 3 GP4 GP1 4 GP3 GP2 PIC12F675 AAT2856 J3 ENA ENA J4 ENB ENB R6 R5 100K 100K (Opt) (Opt C10 330 7 1μ LED7 RED ENS 19 ...
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... Tantalum 1K, 5%, 1/4W; 1206 330, 5%, 1/4W; 1206 100K, 5%, 1/10W; 0603 29.4K, 1%, 1/10W; 0603 78.7K, 1%, 1/10W; 0603 59K, 1%, 1/10W; 0603 Conn. Header, 2mm Zip Red LED; 1206 Switch Tact, SPST, 5mm AAT2856 Manufacturer AnalogicTech Microchip AnalogicTech OSRAM Murata Murata Murata Murata AVX ...
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... High Current Charge Pump with Dual LDO for BacklightApplications Marking 1 Part Number (Tape and Reel) XVXYY TQFN44-28-0.4 2.400 REF 2.600 ± 0.050 Bottom View 0.400 ± 0.050 0.203 REF Pin 1 Indicator AAT2856 2 AAT2856INJ-EE-T1 Detail "A" C0.3 0.430 ± 0.050 Detail "A" 21 ...
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... All other brand and product names appearing in this document are registered trademarks or trademarks of their respective holders. Advanced Analogic Technologies, Inc. 830 E. Arques Avenue, Sunnyvale, CA 94085 Phone (408) 737- 4600 Fax (408) 737- 4611 22 High Current Charge Pump with Dual LDO for BacklightApplications AAT2856 2856.2007.06.1.0 ...