AS1364 AMSCO
Document overview
- Manufacturer or author: Provided By digicamel.com
- PDF pages: 15
Technical content
1 General Description
voltages (using an external resistor-divider network). circuit and thermal-overload conditions.
2 Key Features
3 Applications
battery-operated portable device. Table 1. Standard Products Figure 1. AS1364 - Typical Application Diagram
4 Pinout
Figure 2. Pin Assignments (Top View) Table 2. Pin Descriptions voltage (see Figure 1 on page 1). connected, but they also must be externally connected for proper operation. the OUT pins together externally.
7 SET/BYP
Voltage-Setting Input. Connect to GND to select the factory-preset output voltage.
8 GND Ground
5 Absolute Maximum Ratings
Table 3. Absolute Maximum Ratings State Surface Mount Devices”.
6 Electrical Characteristics
(unless otherwise specified). Typical values are at TAMB = +25ºC. Table 4. Electrical Characteristics
SQC (Statistical Quality Control) methods.
- Guaranteed by production test of load regulation and line regulation.
- Dropout voltage is defined as VIN - VOUT, when VOUT is 100mV below the value of VOUT measured for VIN =
Table 4. Electrical Characteristics (Continued)
7 Typical Operating Characteristics
VIN = VOUT(NOM) + 0.5V, CIN = COUT = 4.7µF, TAMB = 25°C (unless otherwise specified). Figure 7. Quiescent Current vs. VIN; Figure 8. Quiesce nt Current vs. IOUT;
8 Detailed Description
sistor, internal feedback voltage-divider and a comparator (see Figure 16). Figure 16. AS1364 - Block Diagram selected feedback voltage and amplifies the difference. 50mV, the internal feedback path is used and the output is regulated to the factory-preset voltage.
then set to an internally trimmed voltage (see Ordering Information on page 14). power consumption and therefore increasing efficiency. the voltage at SET to exceed the 50mV threshold. Figure 17. Adjustable Output Voltage Typical Application to a (typically OUT) provides a logic control signal. Note: POK is low during shutdown.
www.austriamicrosystems.com Revision 1.05 11 - 15 AS1364 Datasheet - Detailed Description Current Limiter The AS1364 features current limiting circuitry that monitors the pass transistor, limiting short-circuit output current to 1.5A (typ). The circuitry of the AS1364 allows that the output can be shorted to ground for an indefinite period of time without damaging the device. Internal P-Channel Pass Transistor The AS1364 features a 1A P-channel MOSFET pass transistor and consumes only a maximum of 200µA of quiescent current under heavy loads as well as in dropout. Thermal Protection Integrated thermal overload protection limits the total power dissipation in the AS1364. When the junction temperature (TJ) exceeds +170ºC typically, the pass transistor is turned off. Normal operation is continued when TJ drops approxi- mately 20ºC. Note: Regardless of the hysteresis, continuous short-circuit condition will result in a pulsed output. Operating Region and Power Dissipation Maximum power dissipation of the AS1364 depends on the thermal resistance of the package and the PCB, the tem- perature difference between the die junction and ambient air, and the rate of air flow. The power dissipated in the device is given as: The maximum power dissipation is calculated: Where: TJ(MAX) - TAMB is the temperature difference between the device die junction and the surrounding air. θJC is the thermal resistance of the junction to the case. θJA is the thermal resistance from the case through the PCB, copper traces, and other materials to the surrounding air. Connect the exposed thermal pad and GND to circuit ground by using a large pad, or multiple vias to the ground plane. (EQ 3)PD I OUT VIN VOUT–()×= (EQ 4)PDMAX TJM A X() TAMB–
www.austriamicrosystems.com Revision 1.05 12 - 15 AS1364 Datasheet - Application Information
9 Application Information
Capacitor Selection and Regulator Stability Input and output capacitors are required for stable operation of the AS1364 over the full temperature range and with load currents up to 1A. Connect CIN and COUT as close to the AS1364 as possible to minimize the impact of PC board trace inductance. Input Capacitor For CIN, a 4.7µF capacitor between IN and ground is sufficient. CIN reduces the source impedance of the input supply and may be smaller than 4.7µF if powered from regulated power supplies or low-impedance batteries. Larger input capacitor values and lower ESR provide better noise rejection and line-transient response. Output Capacitor A 4.7µF low-ESR capacitor between OUT and ground is sufficient for COUT. The output capacitor’s ESR affects stabil- ity and output noise. An output capacitors with an ESR of 0.5Ω or less is recommended to ensure stability and opti- mum transient response. Reduced output noise and improve load-transient response, stability, and power-supply rejection by using large output capacitors with low ESR. Noise, PSRR, and Transient Response AS1364 output noise is typically 10µVRMS (100Hz to 100kHz) or 45µVRMS (10Hz to 1MHz) during normal operation. This is suitably low for most applications (see Figure 10 on page 7). The AS1364 is designed to achieve extremly low dropout voltage and low quiescent current in battery-powered sys- tems while still maintaining excellent noise performance, transient response, and PSRR. See the Figure 11 on page 7 for a plot of power-supply rejection ratio (PSRR) versus frequency. When operating from very noisy sources, the factory preset variants a recommanded since they offer improved noise performance over the adjustable variants.
The device is available in an 8-pin TDFN 3x3mm package. Figure 18. 8-pin TDFN 3x3mm Package
- Figure 18 is shown for illustration only.
- All dimensions are in millimeters; angles in degrees.
- Dimensioning and tolerancing conform to ASME Y14.5 M-1994.
- N is the total number of terminals.
- The terminal #1 identifier and terminal numbering convention shall conform to JEDEC 95-1, SPP-012. Details of ter-
- Dimension b applies to metallized terminal and is measured between 0.15mm and 0.30mm from the terminal tip.
- ND refers to the maximum number of terminals on side D.
- Unilateral coplanarity zone applies to the exposed heat sink slug as well as the terminals
The device is available as the standard products shown in Table 5. Note: All products are RoHS compliant and Pb-free. Table 5. Ordering Information
www.austriamicrosystems.com Revision 1.05 15 - 15 AS1364 Datasheet Copyrights Copyright © 1997-2009, austriamicrosystems AG, Tobelbaderstrasse 30, 8141 Unterpremstaetten, Austria-Europe. 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 life-support or life-sustaining 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, austriamicrosystems AG 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 tech- nical data herein. No obligation or liability to recipient or any third party shall arise or flow out of austriamicrosystems AG rendering of technical or other services. Contact Information Headquarters austriamicrosystems AG Tobelbaderstrasse 30 A-8141 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