AAT1157 AAT, AAT1157 Datasheet
AAT1157
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AAT1157 Summary of contents
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... The 2.7V to 5.5V input voltage range makes the AAT1157 ideal for single- cell lithium-ion/polymer battery applications. Capable 1.2A with internal MOSFETs, the current-mode controlled IC provides high efficiency over a wide operating range ...
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... Signal ground. Connect the return of all small signal components to this pin. (See board layout rules Enable input pin. A logic high enables the converter; a logic low forces the AAT1157 into shutdown mode reducing the supply current to less than 1µA. The pin should not be left floating N/C Not internally connected. ...
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... Human body model is 100pF capacitor discharged through a 1.5kΩ resistor into each pin. 3. Mounted on a demo board (FR4, in still air). Exposed pad must be mounted to PCB. 4. Derate 20mW/°C above 25°C. 1157.2005.11.1.4 1MHz 1.2A Buck DC/DC Converter 25° AAT1157 Value Units ...
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... Oscillator Frequency OSC Over-Temperature Shutdown T SD Threshold Over-Temperature Shutdown T HYS Hysteresis 1. The AAT1157 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 1MHz 1.2A Buck DC/DC Converter 1 Conditions 0.2 to 5.5V, IN ...
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... N-Channel R 200 180 120°C 160 140 120 100 4.5 5 5.5 2.5 = 1.0A) OUT 1.3 1.28 1.26 1.24 1.22 1 100 2.7 AAT1157 DC Regulation (V = 2.5V) OUT 100 1000 Output Current (mA) vs. Input Voltage DSON 100°C 120°C 85°C 25°C 3 3.5 4 4.5 5 Input Voltage (V) Frequency vs. Input Voltage ( ...
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... V OUT OUT 6.0 4.0 2.0 0.0 -2.0 -4.0 -6.0 -8.0 -10.0 Time (250µ µ s/div) Line Transient (I = 1.2A 2.5V) OUT O 4.4 4.2 4.0 3.8 3.6 3.4 3.2 3.0 2.8 Time (25µ µ s/div) 6 1MHz 1.2A Buck DC/DC Converter = 3.6V) IN 0.02 3.5 0.01 3.0 0 2.5 -0.01 2.0 -0.02 1.5 -0.03 1.0 -0.04 0.5 -0.05 0.0 -0.06 -0.5 0.08 0.24 0.20 0.05 0.02 0.16 0.12 -0.01 0.08 -0.04 -0.07 0.04 0.00 -0.10 -0.04 -0.13 -0.08 -0.16 AAT1157 Output Ripple (V = 2.5V 1.2A 3.6V) OUT OUT IN Time (500ns/div) Load Transient Response (400mA-1.2A 3.3V 2.5V) IN OUT 1.2A 400mA Time (20µ µ s/div) 1157.2005.11.1.4 3 2.5 2 1.5 1 0.5 0 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 ...
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... Functional Block Diagram FB Applications Information Control Loop The AAT1157 is a peak current mode buck converter. The inner wide bandwidth loop controls the inductor peak current. The inductor current is sensed through the P-channel MOSFET (high side) and is also used for short-circuit and overload protection. A fixed slope compensation signal is added to the sensed current to maintain stability for duty cycles greater than 50% ...
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... Input Capacitor The primary function of the input capacitor is to pro- vide a low impedance loop for the edges of pulsed current drawn by the AAT1157. A low ESR/ESL ceramic capacitor is ideal for this function. To mini- mize stray inductance, the capacitor should be placed as closely as possible to the IC. This keeps ...
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... OUT ground at the point of load to improve regulation low pass filter (R1 and C2) provides a clean- er bias source for the AAT1157 active circuitry. C2 should be placed as closely as possible to SGND (Pin 5) and V 6. For good heat transfer, four 15 mil vias spaced mil grid connect the QFN central pad- dle to the bottom side ground plane, as shown in Figures 2 and 3 ...
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... Table 1: Suggested Component Values. Output Voltage JA (V) will vary with 0.8 JA 1.0 1.2 1.5 1.8 . 2.5 3.3 Buck-Boost Output Figure 4 shows how to configure the AAT1157 in a buck boost configuration with an external MOSFET and Schottky diode. The converter has a 3.3V 600mA output with an input voltage ranging from 2.7V to 5.5V AAT1157 267k OUT 3.0µ ...
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... RMS · · 2 · Pesr = esr · 5mΩ · (97.4mA) RMS 1157.2005.11.1.4 1MHz 1.2A Buck DC/DC Converter ⎛ ⎞ 2.5V ⋅ 3.07µH ⎝ ⎠ 4.2V ⎛ ⎞ 2.5V ⋅ 340mA ⎝ ⎠ 4.2V 1 2.5V · (4.2V - 2.5V) · = 97.4mArms 3.0µH · 1MHz · 4.2V 2 · 47.4µW AAT1157 11 ...
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... AAT1157 Dissipation and Junction Temperature Estimate · (R · DSON(HS) O DSON(LS TOTAL V IN · (0.17 Ω · 2.5V + 0.16Ω · (4.2V - 2.5V)) 2 1.2A = 4.2V = 341mW + Θ · 85°C + 50°C/W · 0.341W = 102°C J(MAX) AMB JA TOTAL Surface Mount Inductors Manufacturer Part Number Sumida CDRH5D28-2R6 ...
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... XYY = assembly and date code. 2. Sample stock is generally held on part numbers listed in BOLD. 1157.2005.11.1.4 1MHz 1.2A Buck DC/DC Converter 1 Package Marking Part Number (Tape and Reel) QFN33-16 OEXYY QFN33-16 0.230 ± 0.05 Pin 1 Identification 0.500 ± 0.05 Bottom View 0.203 ± 0.0254 Side View AAT1157 2 AAT1157IVN- ...
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... AnalogicTech deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed. Advanced Analogic Technologies, Inc. 830 E. Arques Avenue, Sunnyvale, CA 94085 Phone (408) 737-4600 Fax (408) 737-4611 14 1MHz 1.2A Buck DC/DC Converter AAT1157 1157.2005.11.1.4 ...