AS1330_12 AMSCO
Document overview
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Technical content
The technical content of this austriamicrosystems datasheet is still valid. Contact information: Headquarters: ams AG Tobelbaderstrasse 30
8141 Unterpremstaetten, Austria
Tel: +43 (0) 3136 500 0 e-Mail: ams_sales@ams.com Please visit our website at www.ams.com
1 General Description
of 150mA @ 3.3V from a single cell. features a power save mode for light loads. AS1330 is equipped with an output disconnect function. the status of the output voltage (POK). The AS1330 is available in a TDFN (2x2mm) 8²pin package.
2 Key Features
3 Applications
Figure 1. AS1330 N Typical Application Diagram
4 Pin Assignments
Figure 2. Pin Assignments (Top View) Table 1. Pin Descriptions
1 SENSE
If the fixed output voltage version is used, connect this pin to VOUT. 3 EN Active-High Enable Input. A logic LOW reduces the supply current to < 1µA. Connect to pin VIN for normal operation.
4 POK
EN is low, an internal 100Ω anti²ringing switch is connected from this pin to VIN to minimize EMI. Note: An optional Schottky diode can be connected between this pin and VOUT . to the output filter capacitor(s) should be as short and wide as is practical.
8 VIN
the bias is derived from VOUT . Thus, once started, operation is completely independent from VIN. Operation is only limited by the output power level and the internal series resistance of the supply. to achieve optimal thermal performance.
7 VOUT
5 GND
5 Absolute Maximum Ratings
bsolute maximum rating conditions for extended periods may affect device reliability. Table 2. Absolute Maximum Ratings
6 Electrical Characteristics
anteed. The parameters with min and max values are guaranteed with production tests or SQC (Statistical Quality Control) methods. Table 3. Electrical Characteristics
- Guaranteed by design and verified in lab characterisation.
- External Schottky diode is mandatory for output voltages higher than 3V.
- VOUT is forced to 3.6V in production test.
7 Typical Operating Characteristics
Figure 7. Efficiency vs. IOUT , Coil Comparision Figure 8. Efficiency vs. IOUT , Coil Comparision
8 Detailed Description
efficiency from light to heavy loads. range, thus increasing battery life in these types of devices. power converter at light loads. The powersave mode is initiated if the output load current falls below a factory programmed threshold. Figure 19. AS1330 N Block Diagram maximum peak inductor current of 650mA (typ), with 1.5ms (approx.) off²time during start²up, allowing the devices to start up into an output load. limiting factor for the application is the ability of the battery to supply sufficient energy to the output. The AS1330 switching frequency is internally fixed at 4MHz allowing the use of very small external components.
www.austriamicrosystems.com/DC²DC_Step²Up/AS1330 Revision 1.06 9 ² 17 AS1330 Datasheet ² Detailed Description Current Sensing A signal representing the internal NMOS²switch current is summed with the slope compensator. The summed signal is compared to the error amplifier output to provide a peak current control command for the PWM. Peak switch current is limited to approximately 650mA independent of VIN or VOUT . Zero Current Comparator The zero current comparator monitors the inductor current to the output and shuts off the PMOS synchronous rectifier once this current drops to 20mA (approx.). This prevents the inductor current from reversing polarity and results in improved converter efficiency at light loads. Anti-Ringing Control Anti²ringing control circuitry prevents high²frequency ringing on pin SW as the inductor current approaches zero. This is accomplished by damping the resonant circuit formed by the inductor and the capacitance on pin SW (CSW ). Powersave Operation In light load conditions, the integrated powersave feature removes power from all circuitry not required to monitor VOUT . When VOUT has dropped approximately 1% from nominal, the device powers up and begins normal PWM operation. C2 recharges, causing the AS1330 to re²enter powersave mode as long as the output load remains below the powersave threshold. The frequency of this intermittent PWM is proportional to load current; i.e., as the load current drops further below the powersave threshold, the AS1330 turns on less frequently. When the load current increases above the powersave threshold, the AS1330 will resume continuous, seamless PWM operation. Notes: 1. An optional capacitor (C FF) between pins VOUT and FB in some applications can reduce VOUTp-p ripple and input quiescent current during powersave mode. Typical values for CFF range from 15 to 220pF. 2. In powersave mode the AS1330 draws only 30µA from the output capacitor(s), greatly improving converter efficiency. Shutdown When pin EN is low the AS1330 is switched off and <1µA current is drawn from the battery; when pin EN is high the device is switched on. If EN is driven from a logic²level output, the logic high²level (on) should be referenced to VOUT to avoid intermittently switching the device on. In shutdown the battery input is disconnected from the output. Thermal Overload Protection To prevent the AS1330 from short²term misuse and overload conditions the chip includes a thermal overload protection. To block the normal operation mode the device is turning the PFET and the NFET off in PWM mode as soon as the junction temperature exceeds 150°C. To resume the normal operation the temperature has to drop below 140°C. Note: Continuing operation in thermal overload conditions may damage the device and is considered bad practice. ams AG Technical content still valid
9 Application Information
digital cameras, MP3 players, GPS receivers, and PC or Memory cards. converters are perfectly suited. ² SENSE to GND: The POK is related to VOUT (see Figure 22 on page 11). Figure 20. AS1330 N Boost Converter, Single AA Cell to 3.0V fixed Output Voltage
www.austriamicrosystems.com/DC²DC_Step²Up/AS1330 Revision 1.06 1 2 ² 17 AS1330 Datasheet ² Application Information Smallest Layout Due to the high switching frequency, the small package and the minimal count of external components, the overall DC²DC system requieres only 6.6x6.6mm of PCB space (see Figure 23). F igure 23. Layout Consideration ams AG Technical content still valid
external ceramic capacitors. The inductor should have low ESR to reduce the I²R power losses, and must be able to handle the peak inductor current without saturating. which result in improved converter efficiency. shielded inductor can be used. recommended as they retain capacitance over wide ranges of voltages and temperatures. to obtain extremely low output voltage ripple and improve transient response. dielectric materials are recommended due to their ability to maintain capacitance over wide voltage and temperature ranges. applications. Larger values may be used without limitations. schottky diode reduces the overshoot on the output signal but on the other hand the output disconnect function is no longer working. Note: Do not use ordinary rectifier diodes, since the slow recovery times will compromise efficiency. Table 4. Recommended External Components
Figure 24. TDFN (2x2mm) 8Npin Marking
Figure 25. TDFN (2x2mm) 8Npin Package
The device is available as the standard products listed in Table 5. ote: All products are RoHS compliant and austriamicrosystems green. Table 5. Ordering Information
www.austriamicrosystems.com/DC²DC_Step²Up/AS1330 Revision 1.06 1 7 ² 17 AS1330 Datasheet Copyrights Copyright © 1997²2012, austriamicrosystems AG, Tobelbaderstrasse 30, 8141 Unterpremstaetten, Austria²Europe. Trademarks Registered ®. All rights reserved. The material herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. All products and companies mentioned are trademarks or registered trademarks of their respective companies. Disclaimer Devices sold by austriamicrosystems AG are covered by the warranty and patent indemnification provisions appearing in its Term of Sale. austriamicrosystems AG makes no warranty, express, statutory, implied, or by description regarding the information set forth herein or regarding the freedom of the described devices from patent infringement. austriamicrosystems AG reserves the right to change specifications and prices at any time and without notice. Therefore, prior to designing this product into a system, it is necessary to check with austriamicrosystems AG for current information. This product is intended for use in normal commercial applications. Applications requiring extended temperature range, unusual environmental requirements, or high reliability applications, such as military, medical life²support or life²sustaining equipment are specifically not recommended without additional processing by austriamicrosystems AG for each application. For shipments of less than 100 parts the manufacturing flow might show deviations from the standard production flow, such as test flow or test location. The information furnished here by austriamicrosystems AG is believed to be correct and accurate. However, austriamicrosystemsAG shall not be liable to recipient or any third party for any damages, including but not limited to personal injury, property damage, loss of profits, loss of use, interruption of business or indirect, special, incidental or consequential damages, of any kind, in connection with or arising out of the furnishing, performance or use of the technical data herein. No obligation or liability to recipient or any third party shall arise or flow out of austriamicrosystemsAG rendering of technical or other services. Contact Information Headquarters austriamicrosystems AG Tobelbaderstrasse 30 A²8141 Unterpremstaetten, Austria Tel: +43 (0) 3136 500 0 Fax: +43 (0) 3136 525 01 For Sales Offices, Distributors and Representatives, please visit: http://www.austriamicrosystems.com/contact ams AG Technical content still valid