AAT1110 SKYWORKS | Alldatasheet
Document overview
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Technical content
Features
VIN range: 2.7 V to 5.5 V VOUT fixed or adjustable from 0.6 V to VIN 27 A no-load quiescent current Output current up to 800 mA 1.4 MHz switching frequency 120 s soft start Fast load transient Over-temperature protection Current limit protection 100% duty cycle low-dropout operation Shutdown current: <1 A Temperature range: 40 °C to +85 °C SC70JW (8-pin, 2.2 mm 2 mm) package (MSL1, 260 °C per JEDEC-J-STD-020)
Description
The AAT1110 SwitchReg™ is a member of Skyworks' Total Power Management IC (TPMIC™) product family. It is a 1.4 MHz step-down converter with an input voltage range of 2.7 V to 5.5 V and output as low as 0.6 V. Its low supply current, small size, and high switching frequency make the AAT1110 the ideal choice for portable applications. The AAT1110 is available in either a fixed version with internal feedback or a adjustable version with external feedback resistors. It can deliver up to 800 mA of load current while maintaining a low 27 A no-load quiescent current. The 1.4 MHz switching frequency minimizes the size of external components while keeping switching losses low. The AAT1110 has excellent load regulation and transient response with a small output inductor and capacitor. The AAT1110 is designed to maintain high efficiency throughout the operating range and provides fast turn-on time. The AAT1110 is available in a space-saving 2.0 mm 2.2 mm SC70JW-8 package and is rated over the 40 °C to +85 °C temperature range. A typical application circuit is shown in Figure 1. The pin configuration is shown in Figure 2. Signal pin assignments and functional pin descriptions are provided in Table 1. Skyworks Green™ products are compliant with all applicable legislation and are halogen-free. For additional information, refer to Skyworks Definition of Green™ , document number SQ04-0074. 4.7 μH 10 μF 4.7 μF EN1 OUT 2 VIN3 LX 4 AGND5 PGND 6 PGND 7 PGND8 AAT1110 VIN VOUT tc87 Figure 1. AAT1110 Typical Application Circuit
Figure 2. AAT1110 8-Pin SC70JW-8 Table 1. AAT1110 Pin Descriptions 3 VIN Input supply voltage for the converter. 4 LX Switching node. Connect the inductor to this pin. It is inte rnally connected to the drain of both high- and low-side MOSFETs. 5 A GND Non-power signal ground pin. 6, 7, 8 P GND Main power ground return pin. Connect to the output and input capacitor return. Table 2, and the electrical specifications are provided in Table 3. Table 2. AAT1110 Absolute Maximum Ratings (Note 1) parameters set at or below their nominal value. Exceeding any of the limits listed may result in permanent damage to the device. Note 2: Mounted on an FR4 board. or equipment, which can discharge without detection. Industry-standard ESD precautions should be used at all times.
Table 3. AAT1110 Electrical Specifications (Note 1) Note 1: Performance is guaranteed only under the conditions listed in this Table.
to the internal error amplifier. Figure 25. AAT1110 Functional Block Diagram A functional block diagram is shown in Figure 25. provide improved transient response (see Figure 26). the P-channel high-side MOSFET. programmed current source in parallel with the output capacitor. amplifier reference is fixed at 0.6 V.
Figure 26. Enhanced Transient Response Schematic for a series of four consecutive clock cycles. output voltage automatically recovers. operation of all internal circuitry prior to activation. In this case, a standard 6.8 H value is selected. For high-voltage fixed versions ( 2.5 V), m = 0.48 A/s. when VIN is double the output voltage.
PRELIMINARY DATA SHEET • AAT1110 FAST TRANSIENT 800 MA STEP-DOWN CONVERTER Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com 10 September 11, 2013 • Skyworks Proprietary Information • Pr oducts and Product Information are Subject to Change Without Notice • 201971D S OUT PP )MIN(IN f4ESRI V Where, fS is the switching frequency. Always examine the ceramic capacitor DC voltage coefficient characteristics when selecting the proper value. For example, the capacitance of a 10 F, 6.3 V, X5R ceramic capacitor with 5.0 V DC applied is actually about 6 F. The maximum input capacitor RMS current is: IN OUT IN OUT OUTRMS V V1V VII The input capacitor RMS ripple current varies with the input and output voltage and always is less than or equal to half of the total DC load current. 2 15.0D1DV V1V V 2 IN OUT IN for VIN = 2 VOUT II OUT MAXRMS ）（ The term IN OUT IN OUT V V1V V appears in both the input voltage ripple and input capacitor RMS current equations and is a maximum when VOUT is twice VIN. This is why the input voltage ripple and the input capacitor RMS current ripple are a maximum at 50% duty cycle. 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. The proper placement of the input capacitor (C2) can be seen in the evaluation board layout in Figure 28. A laboratory test setup typically consists of two long wires running from the bench power supply to the evaluation board input voltage pins. The inductance of these wires, along with the low-ESR ceramic input capacitor, can create a high-Q network that may affect converter performance. This problem often becomes apparent in the form of excessive ringing in the output voltage during load transients. Errors in the loop phase and gain measurements can also result. Because the inductance of a short PCB trace feeding the input voltage is significantly lower than the power leads from the bench power supply, most applications do not exhibit this problem. In applications where the input power source lead inductance cannot be reduced to a level that does not affect the converter performance, a high ESR tantalum or aluminum electrolytic should be placed in parallel with the low ESR, ESL bypass ceramic. This dampens the high-Q network and stabilizes the system. Output Capacitor The output capacitor limits the output ripple and provides holdup during large load transitions. A 4.7 F to 10 F X5R or X7R ceramic capacitor typically provides sufficient bulk capacitance to stabilize the output during large load transitions and has the ESR and ESL characteristics necessary for low output ripple. The output voltage droop due to a load transient (I LOAD) is dominated by the capacitance of the ceramic output capacitor. During a step increase in load current, the ceramic output capacitor alone supplies the load current until the loop responds. Within two or three switching cycles, the loop responds and the inductor current increases to match the load current demand. The relationship of the output voltage droop during the three switching cycles to the output capacitance can be estimated by: SDROOP LOAD OUT fV I3C Once the average inductor current increases to the DC load level, the output voltage recovers. The above equation establishes a limit on the minimum value for the output capacitor with respect to load transients. The internal voltage loop compensation also limits the minimum output capacitor value to 4.7 F. This is due to its effect on the loop crossover frequency (bandwidth), phase margin, and gain margin. Increased output capacitance reduces the crossover frequency with greater phase margin. The maximum output capacitor RMS ripple current is given by: )MAX(INS OUT)MAX(INOUT MAXRMS VfL VVV 1I 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.
immunity, the minimum suggested value for R2 is 59 k. reduced no-load input current. requires a larger output capacitor C1 for stability. Table 4. Adjustable Resistor Values for Use with 0.6 V Step- the complete input voltage range. to VIN (Pin 3) and PGND (Pins 6-8). in Figure 27. The PCB layer details are shown in Figure 28.
Table 5. Evaluation Board Component Values Note 1: For reduced quiescent current, R2 = 221 k. Table 6. Typical Surface Mount Inductors Table 7. Surface Mount Capacitors
PRELIMINARY DATA SHEET • AAT1110 FAST TRANSIENT 800 MA STEP-DOWN CONVERTER Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com 201971D • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • September 11, 2013 15
Ordering Information
Model Name Output Voltage (Note 1) Package Marking (Note 2) Manufacturing Part Number (Note 3) AAT1110 Fast Transient 800 mA Step-Down Converter 3.3 V SC70JW-8 TSXYY AAT1110IJS-3.3-T1 Adj. 0.6 V SC70JW-8 SRXYY AAT1110IJS-0.6-T1 Note 1: Contact Sales for other voltage options. Note 2: XYY = assembly and date code. Note 3: Sample stock is generally held on part numbers listed in BOLD. Copyright © 2013 Skyworks Solutions, Inc. All Rights Reserved. Information in this document is provided in connection with Skyworks Solutions, Inc. (“Skyworks”) products or services. These materials, including the information contained herein, are provided by Skyworks as a service to its customers and may be used for informational purposes only by the customer. Skyworks assumes no responsibility for errors or omissions in these materials or the information contained herein. Skyworks may change its documentation, products, services, specifications or product descriptions at any time, without notice. Skyworks makes no commitment to update the materials or information and shall have no responsibility whatsoever for conflicts, incompatibilities, or other difficulties arising from any future changes. No license, whether express, implied, by estoppel or otherwise, is granted to any intellectual property rights by this document. Skyworks assumes no liability for any materials, products or information provided hereunder, including the sale, distribution, reproduction or use of Skyworks products, information or materials, except as may be provided in Skyworks Terms and Conditions of Sale. THE MATERIALS, PRODUCTS AND INFORMATION ARE PROVIDED “AS IS” WITHOUT WARRANTY OF ANY KIND, WHETHER EXPRESS, IMPLIED, STATUTORY, OR OTHERWISE, INCLUDING FITNESS FOR A PARTICULAR PURPOSE OR USE, MERCHANTABILITY, PERFORMANCE, QUALITY OR NON-INFRINGEMENT OF ANY INTELLECTUAL PROPERTY RIGHT; ALL SUCH WARRANTIES ARE HEREBY EXPRESSLY DISCLAIMED. SKYWORKS DOES NOT WARRANT THE ACCURACY OR COMPLETENESS OF THE INFORMATION, TEXT, GRAPHICS OR OTHER ITEMS CONTAINED WITHIN THESE MATERIALS. SKYWORKS SHALL NOT BE LIABLE FOR ANY DAMAGES, INCLUDING BUT NOT LIMITED TO ANY SPECIAL, INDIRECT, INCIDENTAL, STATUTORY, OR CONSEQUENTIAL DAMAGES, INCLUDING WITHOUT LIMITATION, LOST REVENUES OR LOST PROFITS THAT MAY RESULT FROM THE USE OF THE MATERIALS OR INFORMATION, WHETHER OR NOT THE RECIPIENT OF MATERIALS HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. Skyworks products are not intended for use in medical, lifesaving or life-sustaining applications, or other equipment in which the failure of the Skyworks products could lead to personal injury, death, physical or environmental damage. Skyworks customers using or selling Skyworks products for use in such applications do so at their own risk and agree to fully indemnify Skyworks for any damages resulting from such improper use or sale. Customers are responsible for their products and applications using Skyworks products, which may deviate from published specifications as a result of design defects, errors, or operation of products outside of published parameters or design specifications. Customers should include design and operating safeguards to minimize these and other risks. Skyworks assumes no liability for applications assistance, customer product design, or damage to any equipment resulting from the use of Skyworks products outside of stated published specifications or parameters. Skyworks, the Skyworks symbol, and “Breakthrough Simplicity” are trademarks or registered trademarks of Skyworks Solutions, Inc., in the United States and other countries. Third-party brands and names are for identification purposes only, and are the property of their respective owners. Additional information, including relevant terms and conditions, posted at www.skyworksinc.com, are incorporated by reference.