AAT1110 AAT, AAT1110 Datasheet

Page 1

... AAT1110 the ideal choice for portable applications. The AAT1110 is available in either a fixed version with internal feedback or a programmable version with external feedback resistors. It can deliver up to 800mA of load current while maintaining a low 27µ ...

Page 2

... AGND Non-power signal ground pin PGND Main power ground return pin. Connect to the output and input capacitor return. Pin Configuration 2 Fast Transient 800mA Step-Down Converter SC70JW-8 (Top View) EN PGND 8 1 OUT PGND 2 7 VIN PGND AGND 4 5 AAT1110 1110.2006.04.1.0 ...

Page 3

... Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at condi- tions other than the operating conditions specified is not implied. Only one Absolute Maximum Rating should be applied at any one time. 2. Mounted on an FR4 board. 1110.2006.04.1.0 Fast Transient 800mA Step-Down Converter 1 (SC70JW-8) 2 AAT1110 Value Units 6 ...

Page 4

... EN(L) V Enable Threshold High EN(H) I Input Low Current EN 1. The AAT1110 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. 4 Fast Transient 800mA Step-Down Converter 1 = 25° Conditions ...

Page 5

... Output Current (mA) 1110.2006.04.1.0 Fast Transient 800mA Step-Down Converter 1.0 V 0.5 = 4.2V 0.0 -0.5 -1.0 0.1 100 1000 2.0 1.5 V 1.0 = 5.0V IN 0.5 0.0 -0.5 V -1.0 -1.5 -2.0 100 1000 0.1 1.0 0.5 0.0 -0.5 -1.0 100 1000 0.1 AAT1110 DC Regulation (V = 1.8V) OUT = 100 Output Current (mA) DC Regulation (V = 2.5V) OUT = 100 Output Current (mA) DC Regulation (V = 3.3V 6.8µH) OUT ...

Page 6

... Switching Frequency vs. Temperature = 400mA) 15.0 12.0 9.0 6.0 3.0 0.0 -3.0 -6.0 -9.0 -12.0 -15 100 -40 No Load Quiescent Current vs. Input Voltage 85° 3.3V OUT -40° 4.7 5.1 5.5 2.7 AAT1110 Line Regulation (V = 1.8V) OUT I = 400mA OUT I = 800mA OUT I = 1mA OUT I = 10mA OUT 3.0 3.5 4.0 4.5 5.0 5.5 Input Voltage ( 3.6V 1.8V) IN OUT - Temperature (° ° C) 25° ...

Page 7

... Fast Transient 800mA Step-Down Converter = 1.8V; OUT 2.0 1.9 1.8 1.7 0.5 0.0 -0.5 = 1.8V; (600mA to 800mA; V OUT 2.0 1.9 1.8 1.7 0.5 0.0 -0.5 = 1.8V; (600mA to 800mA; V OUT 2.0 1.9 1.8 1.7 0.5 0.0 -0.5 AAT1110 Load Transient Response (600mA to 800mA 3.6V 1.8V; IN OUT C = 10µF) 1 Time (50µs/div) Load Transient Response = 3.6V 1.8V; IN OUT C = 22µF) 1 Time (50µs/div) Load Transient Response = 3.6V 1.8V; IN OUT C = 10µ 100pF Time (50µ ...

Page 8

... Fast Transient 800mA Step-Down Converter 20 7.6 7.1 10 6.6 0 6.1 -10 5.6 5.1 -20 4.6 -30 4.1 -40 3.6 -50 3.1 2.6 -60 P-Channel R = 1mA) 750 0.30 700 0.25 650 0.20 600 0.15 550 0.10 500 0.05 450 400 0.00 350 -0.05 300 -0.10 2.5 5.0 5.5 6.0 AAT1110 Output Ripple (V = 3.6V 1.8V 800mA) IN OUT OUT Time (500ns/div) vs. Input Voltage DS(ON) 120°C 100°C 85°C 25°C 3.0 3.5 4.0 4.5 5.0 5.5 Input Voltage (V) 1110.2006.04.1.0 1.3 1.2 1.1 1.0 0.9 0.8 0.7 0.6 0.5 6.0 ...

Page 9

... Note: For adjustable version, the internal feedback divider is omitted and the OUT pin is tied directly to the internal error amplifier. Functional Description The AAT1110 is a high performance 800mA 1.4MHz monolithic step-down converter. It has been designed with the goal of minimizing external com- ponent size and optimizing efficiency over the com- plete load range ...

Page 10

... For the adjustable output, the error amplifier reference is fixed at 0.6V. Soft Start / Enable Soft start limits the current surge seen at the input and eliminates output voltage overshoot. When pulled low, the enable input forces the AAT1110 into 10 Fast Transient 800mA Step-Down Converter ...

Page 11

... The internal slope compensation for the adjustable and low-voltage fixed versions of the AAT1110 is 0.24A/µsec. This equates to a slope compensation that is 75% of the inductor current down slope for a 1.5V output and 4.7µH inductor. 0.75 ⋅ V 0.75 ⋅ ...

Page 12

... The input capacitor provides a low impedance loop for the edges of pulsed current drawn by the AAT1110. Low ESR/ESL X7R and X5R ceramic capacitors are ideal for this function. To minimize stray inductance, the capacitor should be placed as closely as possible to the IC. This keeps the high frequency content of the input current localized, minimizing EMI and input voltage ripple ...

Page 13

... Figure 2: AAT1110 Evaluation Board Top Side. The maximum output capacitor RMS ripple current is given by · (V OUT IN(MAX · RMS(MAX) L · F · · 3 Dissipation due to the RMS current in the ceramic output capacitor ESR is typically minimal, resulting in less than a few degrees rise in hot-spot temperature. ...

Page 14

... With 0.6V Step-Down Converter. V OUT C1 10μF GND GND2 Figure 5: AAT1110 Adjustable Evaluation Board Schematic. 14 Fast Transient 800mA Step-Down Converter Thermal Calculations There are three types of losses associated with the AAT1110 step-down converter: switching loss- es, conduction losses, and quiescent current loss- es. Conduction losses are associated with the ...

Page 15

... T J(MAX) TOTAL JA 1110.2006.04.1.0 Fast Transient 800mA Step-Down Converter Layout The suggested PCB layout for the AAT1110 is shown in Figures 2, 3, and 4. The following guide- lines should be used to help ensure a proper layout. · The input capacitor (C2) should connect closely as possible to VIN (Pin 3) and PGND (Pins 6-8) ...

Page 16

... 5mΩ · (45mA) 2 esr RMS 16 16 Fast Transient 800mA Step-Down Converter (use 4.7µH; see Table 1) ⎛ ⎞ 1.8V ⋅ 156mA ⎝ ⎠ 4.2V = 6.4μF; use 10µF 1 1.8V · (4.2V - 1.8V) = · = 45mArms 4.7μH · 1.4MHz · 4.2V 2 · 10μW AAT1110 = 300mA LOAD 1110.2006.04.1.0 1110.2006.04.1.0 ...

Page 17

... PP - ESR · 4 · F ⎝ ⎠ ⎝ 0. 0.3Arms RMS esr · 5mΩ · (0.3A) = 0.45mW RMS AAT1110 Losses 2 I · (R · DSON(HS) O DSON(LS TOTAL · F · · · (0.725 Ω · 1.8V + 0.7Ω · [4.2V - 1.8V ...

Page 18

... R1 (kΩ Ω Table 3: Evaluation Board Component Values. Inductance Max DC (µH) Current (A) 2.2 1.20 4.7 0.90 6.8 0.73 4.7 0.80 4.7 0.98 6.8 0.82 4.7 1.30 Value 4.7µF 10µF 22µF Table 5: Surface Mount Capacitors. AAT1110 1 L1 (µH) 2.2 2.2 2.2 2.2 2.2 2.2 4.7 4.7 4.7 4.7 6.8 6.8 6.8 L1 (µH) 4.7 DCR Size (mm) (Ω Ω ) LxWxH Type 0.072 3.8x3.8x1.8 Shielded 0.105 3.8x3.8x1.8 Shielded 0.170 3 ...

Page 19

... Advanced Analogic Technologies, Inc. 830 E. Arques Avenue, Sunnyvale, CA 94085 Phone (408) 737-4600 Fax (408) 737-4611 1110.2006.04.1.0 Fast Transient 800mA Step-Down Converter Marking 2 SRXYY SC70JW-8 0.225 ± 0.075 0.100 0.45 ± 0.10 2.10 ± 0.30 AAT1110 Part Number (Tape and Reel) 3 AAT1110IJS-0.6-T1 0.048REF 4° ± 4° 19 ...