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| AS1907, AS1908 , AS1909 L o w - Vo l ta g e M i c r o p r o c e s s o r R e s e t C i r c u i ts D a ta S he e t 1 General Description The AS1907/AS1908/AS1909 microprocessor supervisory circuits are ideal for monitoring the supply voltage of digital systems and microprocessors. The devices are designed to initiate a reset if the supply voltage goes below a predefined threshold. The duration of the reset is either 1.5, 30, or 150ms (typ.) after the supply voltage has risen above the pre-set threshold (see Ordering Information on page 9). The devices are available as the standard products listed in Table 1. Table 1. Standard Products Model AS1907 AS1908 AS1909 Output Type Push/Pull Push/Pull Open-Drain Reset Type Active-Low Active-High Active-Low 2 Key Features ! 3 Output Types: Push/Pull RESET, Push Pull RESETN, and Open Drain RESETN Reset Threshold Range: 1.6 to 2.5V (~100mV increments) RESET/RESETN: - Valid to VCC = 0.7V (AS1907 and AS1908) - Valid to VCC = 1.0V (AS1909) Reset Pulse Widths: 1, 20, and 100ms Supply Voltage Range: +0.7 to +3.6V Supply Current Range: 2.6 to 7.0A Power Supply Transient Immunity Requires No External Components Operating Temperature Range: -40 to +125C 3-pin SOT23 Package ! ! ! ! ! ! ! ! The reset thresholds are factory-set between 1.6 and 2.5V in steps of approximately 100mV (see Table 5 on page 7). The devices exhibit excellent reliability, and can reduce system costs by eliminating the need for external components. The extremely low current consumption makes the devices ideal for use in portable applications. The integrated reset comparator was specifically designed to ignore fast transients on VCC. The devices are available in a 3-pin SOT23 package. ! 3 Applications The devices are ideal for use in cordless and mobile phones, MP3 players, CD and DVD players, PDAs, handheld computers, digital cameras, hard drives, and any other application where power supply supervisory control is required. Figure 1. Application Diagrams VCC VCC 3 VCC 3 VCC VCC 3 VCC 3 VCC VCC 3 VCC 3 Microprocessor Microprocessor Microprocessor AS1907 RESETN 2 RESET I/O AS1908 2 RESET RESET I/O AS1909 2 RESETN RESET I/O GND 1 GND 1 GND 1 GND 1 GND 1 GND 1 www.austriamicrosystems.com Revision 1.05 1 - 10 AS1907/AS1908/AS1909 Data Sheet - P i n o u t 4 Pinout Pin Assignments Figure 2. Pin Assignments (Top View) GND 1 AS1908/ AS1907/ AS1909 RESET, RESETN 2 3 VCC Pin Descriptions Table 2. Pin Descriptions Pin Number 1 Pin Name GND RESET 2 RESETN Ground Active-High Reset Output (AS1908). This pin stays high whenever VCC is below the RESET threshold VTH (see page 7), and for tTP (see page 4) after VCC rises above VTH. Active-Low Reset Output (AS1907, AS1909). This pin remains low while VCC is below the RESET threshold VTH (see page 7), and for tTP (see page 4) after VCC rises above VTH. Note: This pin is open-drain on the AS1909. Positive Supply Voltage. Connect to +0.7 to +3.6V supply. Description 3 VCC www.austriamicrosystems.com Revision 1.05 2 - 10 AS1907/AS1908/AS1909 Data Sheet - A b s o l u t e M a x i m u m R a t i n g s 5 Absolute Maximum Ratings Stresses beyond those listed in Table 3 may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in Section 6 Electrical Characteristics on page 4 is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Table 3. Absolute Maximum Ratings Parameter VCC RESET, RESETN Push/Pull RESETN Open Drain Input Current (VCC) Output Current (RESET, RESETN) Continuous Power Dissipation (TAMB = +70C) Operating Temperature Range Storage Temperature Range -40 -65 Min -0.3 -0.3 -0.3 Max +5 VCC + 0.3 +6 20 20 320 +125 +160 Units V V V mA mA mW C C The reflow peak soldering temperature (body temperature) specified is in accordance with IPC/JEDEC J-STD-020C "Moisture/Reflow Sensitivity Classification for Non-Hermetic Solid State Surface Mount Devices" 3-pin SOT23 derate 4mW/C above +70C Comments Package Body Temperature +260 C www.austriamicrosystems.com Revision 1.05 3 - 10 AS1907/AS1908/AS1909 Data Sheet - E l e c t r i c a l C h a r a c t e r i s t i c s 6 Electrical Characteristics VCC = Full Range, TAMB = -40 to +125C (unless otherwise specified). Typ values are at VCC = +3.0V, TAMB = +25C. Table 4. Electrical Characteristics Parameter Symbol Conditions TAMB = 0 to +85C Supply Voltage Range VCC TAMB = -40 to +85C AS1907, AS1908 AS1909 AS1907, AS1908 AS1909 Min 0.7 1.0 0.78 1.2 1.2 2.4 2.6 VTH 0.9% VTH 1.2% VTH 3% 1 20 100 VTH VTH VTH 33 1.5 30 150 2 40 200 0.4 0.3 0.8 x VCC 0.8 x VCC 0.8 x VCC 0.8 x VCC 0.3 0.3 0.5 V ms Typ Max 3.6 3.6 3.6 3.6 3.6 6.0 7.0 VTH + 0.9% VTH + 1.2% VTH + 3% A V V V s V Unit TAMB = -40 to +125C Supply Current 1 ICC VCC = 1.8V, no load VCC = 2.5V, no load TAMB = +25C RESET Threshold Voltage VTH TAMB = 0C to +50C; AS1909C17 and AS1909C168 only TAMB = -40 to +125C VCC Falling Reset Delay RESET Active Time-Out Period RESETN Output Low Voltage; RESET asserted (AS1907/AS1909) RESETN Output High Voltage; RESET Not Asserted (AS1907) tRD tTP VCC falling at 10V/ms AS190x-Azz-T AS190x-Bzz-T AS190x-Czz-T ISINK = 50A, VCC 1.0V VOL ISINK = 500A, VCC 1.8V ISOURCE = 200A, VCC 1.8V VOH ISOURCE = 500A, VCC 2.7V ISOURCE = 1A, VCC 1.0V VOH ISOURCE = 200A, VCC 1.8V VOL ILEAK ISINK = 500A, VCC 1.8V ISINK = 1.2mA, VCC 2.7V VCC > VTH V RESET Output Voltage; RESET Asserted (AS1908) RESET Output Voltage; RESET Not Asserted (AS1908) RESETN Output Leakage Current; RESETN Deasserted (AS1909) 1. Not valid if VCC = VTH. V V A www.austriamicrosystems.com Revision 1.05 4 - 10 AS1907/AS1908/AS1909 Data Sheet - Ty p i c a l O p e r a t i n g C h a r a c t e r i s t i c s 7 Typical Operating Characteristics TAMB = +25C (unless otherwise specified). Figure 3. Supply Current vs. Temperature 3.2 3 2.8 2.6 VCC = 1.8V VCC = 2.5V Figure 4. Supply Current vs. Supply Voltage 6 5 4 3 2 1 0 Supply Current (A) . 2.4 2.2 2 -50 Supply Current (A) . -25 0 25 50 75 100 125 1.4 1.8 2.2 2.6 3 3.4 3.8 Temperature (C) Supply Voltage (V) Figure 5. Normalized Reset Timeout Period vs. Temperature, VTH = 2.3V 1.3 Figure 6. Output Voltage Low vs. Temperature Reset Asserted 75 . . Norm. Reset Timeout Period 65 55 45 35 25 15 5 -50 VCC = 1.0V ISINK = 50A 1.2 Output Voltage Low (mV) VCC = 1.8V ISINK = 500A 1.1 VCC = 2.2V ISINK = 500A 1 VCC = 0.7V ISINK = 50A 0.9 -50 -25 0 25 50 75 100 125 -25 0 25 50 75 100 125 Temperature (C) Temperature (C) Figure 7. Max. Transient Duration vs. Reset Comparator Overdrive 700 Figure 8. VCC falling Propagation Delay vs. Temperature 140 120 100 80 60 40 20 0 -50 VCC falling at 10V/ms VCC falling at 1V/ms . 600 500 400 Reset Occurs Max. Transient Duration (s) 300 200 100 0 0.1 Reset does not Occur 1 10 100 1000 Propagation Delay (s) . -25 0 25 50 75 100 125 Reset Comparator Overdrive (mV) Temperature (C) www.austriamicrosystems.com Revision 1.05 5 - 10 AS1907/AS1908/AS1909 Data Sheet - Ty p i c a l O p e r a t i n g C h a r a c t e r i s t i c s Figure 9. Output Voltage Low vs. VCC, ISINK = 50A 60 Temp = -40C Temp = +25C Temp = +85C Temp = +125C Figure 10. Output Voltage Low vs. VCC, ISINK = 100A 80 Temp = -40C Temp = +25C Temp = +85C Temp = +125C . . Output Voltage Low (mV) 2.2 Output Voltage Low (mV) 50 40 30 20 10 0 0.7 1 1.3 1.6 70 60 50 40 30 20 10 0 1.9 0.7 1 1.3 1.6 1.9 2.2 VCC (V) VCC (V) Figure 11. Output Voltage Low vs. VCC, ISINK = 500A 250 Temp = -40C Temp = +25C Temp = +85C Temp = +125C . Output Voltage Low (mV) 200 150 100 50 0 0.7 1 1.3 1.6 1.9 2.2 VCC (V) www.austriamicrosystems.com Revision 1.05 6 - 10 AS1907/AS1908/AS1909 Data Sheet - A p p l i c a t i o n I n f o r m a t i o n 8 Application Information Negative Going VCC Transients All devices are effectively immune to short-duration, negative-going VCC transients (glitches). The Maximum Transient Duration vs. Reset Comparator Overdrive graph (see page 5) shows the maximum pulse width that a negative-going VCC transient may typically have without issuing a reset signal. As the amplitude of the transient increases, the maximum allowable pulse width decreases. Valid Reset Output If VCC falls below 1V and approaches the minimum operating voltage of 0.7V, push/pull-type reset sinking/sourcing capabilities greatly decrease. High-impedance CMOS-logic inputs connected to RESET can drift to indeterminate voltages, although this is normally not a problem since most microprocessors do not operate at VCC < 1V. For the AS1908, where RESET must be valid to VCC = 0, a 100k pull-up resistor between RESET and VCC (see Figure 1 on page 1) will hold RESET high if VCC falls below 0.7V. For the AS1907, where RESET must be valid down to 0V, add a pull-down resistor between RESET and GND (see Figure 1 on page 1) to eliminate stray leakage currents and hold RESET low. A pull-down resistor of 100k is large enough not to load RESET yet small enough to pull it low. Since the AS1909 has an open-drain, active-low output, it typically uses a pull-up resistor. With this device, RESET will most likely not maintain an active condition, but will drift to a non-active level due to the pull-up resistor and the reduced sinking capability of the open drain device. Therefore, this device is not recommended for applications where the RESET pin is required to be valid down to VCC = 0. Table 5. Reset Thresholds Reset Thresholds TAMB = +25C Suffix 25 24 23 22 21 20 19 18 17 16 Min 2.478 2.378 2.279 2.180 2.081 1.982 1.883 1.784 1.685 1.586 Typ 2.50 2.40 2.30 2.20 2.10 2.00 1.90 1.80 1.70 1.60 Max 2.523 2.422 2.321 2.220 2.119 2.018 1.917 1.816 1.715 1.614 TAMB = -40 to +125C Min 2.43 2.33 2.23 2.13 2.04 1.94 1.84 1.75 1.65 1.55 Max 2.58 2.47 2.37 2.27 2.18 2.06 1.96 1.85 1.75 1.65 Bi-Directional Microprocessor Interface The RESET output on the AS1909 is open-drain, thus this device can interface easily with microprocessors that have bi-directional reset pins, such as the Motorola 68HC11. Connect the RESET output of this device directly to the microprocessor's RESET I/O pin with a single pull-up resistor to allow either device to assert reset (see Figure 1 on page 1). Layout Considerations The devices require proper layout and design procedures for optimum performance. ! ! ! Short, wide traces should be used to reduce stray inductance and capacitance. Bypass capacitors should be as close to the device as possible. Large ground planes should be used wherever possible. www.austriamicrosystems.com Revision 1.05 7 - 10 AS1907/AS1908/AS1909 Data Sheet - P a c k a g e D r a w i n g s a n d M a r k i n g s 9 Package Drawings and Markings The devices are available in an 3-pin SOT23 package. Figure 12. 3-pin SOT23 Package Symbol A A1 B C D E e H L S Min 0.787 0.025 0.356 0.086 2.667 1.194 1.778 2.083 0.102 0.432 0 Max 1.194 0.127 0.559 0.152 3.048 1.397 2.032 2.489 0.305 0.559 8 Notes: 1. Dimensions D and E do not include mold flash. 2. Mold flash protrusions not to exceed .15mm (.006"). 3. Controlling dimension: millimeter. www.austriamicrosystems.com Revision 1.05 8 - 10 AS1907/AS1908/AS1909 Data Sheet - O r d e r i n g I n f o r m a t i o n 10 Ordering Information The devices are available as the following standard products. Table 6. Ordering Information Type AS1908C18-T AS1908C20-T AS1907C16-T AS1907C18-T AS1907C20-T AS1907C22-T AS1907B23-T AS1909C16-T AS1909C168-T AS1909C17-T AS1909C18-T AS1909C20-T AS1909C22-T AS1909C23-T Marking ASHU ASHV ASHP ASHQ ASHR ASNB ASHX ASHY ASSB ASHZ ASND ASH1 ASNC ASH2 Reset Type Active High Active High Active Low Active Low Active Low Active Low Active Low Open Drain Open Drain Open Drain Open Drain Open Drain Open Drain Open Drain Reset Threshold 1.8V 2.0V 1.6V 1.8V 2.0V 2.2V 2.3V 1.6V 1.68V 1.7V 1.8V 2.0V 2.2V 2.3V Minimum Reset Timeout 100ms 100ms 100ms 100ms 100ms 100ms 20ms 100ms 100ms 100ms 100ms 100ms 100ms 100ms Delivery Form Tape and Reel Tape and Reel Tape and Reel Tape and Reel Tape and Reel Tape and Reel Tape and Reel Tape and Reel Tape and Reel Tape and Reel Tape and Reel Tape and Reel Tape and Reel Tape and Reel Non-standard versions require a minimum order of 30,000 units. Contact austriamicrosystems, AG for availability of non-standard versions. Table 7. Coding of Factory-Trimmed Reset Active Time-Out Period Device AS1907xyy-T* AS1908xyy-T* AS1909xyy-T* Suffix A B C tTP in Milliseconds Min 1 20 100 Typ 1.5 30 150 Max 2 40 200 All devices are RoHS compliant and free of halogene substances. * These devices are available in factory-set VCC reset thresholds from 1.6V to 2.5V, in approximately 100mV increments. Choose the desired reset threshold suffix from (see Table 5 on page 7) and insert it instead of "yy" in the part number. Factory-programmed reset timeout periods are also available. Insert the code corresponding to the desired nominal reset timeout period (see Table 7) instead of "x" in the part number. All devices available in tape-and-reel only. www.austriamicrosystems.com Revision 1.05 9 - 10 AS1907/AS1908/AS1909 Data Sheet Copyrights Copyright (c) 1997-2009, austriamicrosystems AG, Schloss Premstaetten, 8141 Unterpremstaetten, Austria-Europe. Trademarks Registered (R). 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 lifesustaining 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 technical 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 A-8141 Schloss Premstaetten, 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-us www.austriamicrosystems.com Revision 1.05 10 - 10 |
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