AS1901, AS1902, AS1903 D a ta S he e t Ultra Low-Power P Supervisory Circuit 1 General Description 2 Key Features The AS1901/2/3 family is an ultra low-power supervisory circuit device. The device can be used to monitor the supply voltage of digital systems and microprocessors and initiate a reset when the voltage goes below a predefined threshold. The duration of the reset is 5/20/100/500ms (typ.) after the supply voltage has risen above the threshold. The AS1901/2/3 exhibit excellent reliability and can reduce application costs by eliminating all external components. ! Low 230nA (typ) Supply Current ! Precision Monitoring of 2.5-, 3-, and 3.3V-Power Supplies ! Supply Voltage Range: 1.0 to 3.6V ! Reset Threshold Range: 2.2 to 3.1V ! Available in 3 Versions: - AS1901 Push Pull RESETN - AS1902 Push Pull RESET The device is available with different output drivers: - AS1903 Open Drain RESETN ! The AS1901 has a push-pull driver with an active low reset. ! The AS1902 uses the same output stage as the AS1901, but has an active high reset. ! The AS1903 has an open drain output with active low reset. ! 4 Time-Out Periods Ranging from 5 to 500ms ! Detection Voltage Accuracy: 1.5% ! Temperature Range: -40 to +85C ! Package: SOT23-3 All devices operate down to a voltage of 1V. The reset thresholds are factory-trimmable between 2.2V and 3.08V in steps of approximately 100mV. 3 Applications Each device of the AS1901/2/3 family is offered with four time-out periods of 5/20/100/500ms. The devices are ideal for computers, intelligent instruments, controllers, critical microprocessor and microcontroller, power monitoring and portable/batterypowered equipment. The extremely low current consumption of only 230nA (typ) at 3.3V makes the device ideal for use in portable applications. All devices are available in a 3-pin SOT23 package. Figure 1. Functional Block Diagrams VCC VCC 3 3 VDD VCC AS1901 AS1902 RESETN, RESET VDD Microprocessor 2 GND www.austriamicrosystems.com AS1903 RESET RESETN GND GND 1 VCC Microprocessor 2 RESET I/O GND 1 Revision 1.51 1-9 AS1901, AS1902, AS1903 Data Sheet - P i n o u t 4 Pinout Pin Assignments Figure 2. Pin Assignments (Top View) Top View GND 1 AS1901 AS1902 AS1903 RESETN, RESET 3 VDD 2 SOT23-3 Pin Descriptions Table 1. Pin Descriptions Pin Number Pin Name Description 1 GND Ground 2 - RESETN Active-low reset output. RESETN remains low while VDD is below the reset threshold and for tTP after VDD rises above the reset threshold. RESETN is open-drain on the AS1903 and push-pull on the AS1901. - 2 RESET Active-high reset output. RESET remains high while VDD is below the reset threshold and for tTP after VDD rises above the reset threshold. 3 3 VDD Supply voltage. AS1901/AS1903 AS1902 1 www.austriamicrosystems.com Revision 1.51 2-9 AS1901, AS1902, AS1903 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 2 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 is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Table 2. Absolute Maximum Ratings (TA = 25C Unless Otherwise Noted) Parameter Limits Unit VDD to GND -0.3 to +5 V RESET/RESETN to GND -0.3 to VDD + 0.3 V Input Current (VDD) 20 mA Output Current (RESET, RESETN) 20 mA Rate of Rise (VDD) 100 V/s Operating Temperature Range (TA) -40 to +85 C Storage Temperature Range -65 to +150 C Package-Body Peak Temperature www.austriamicrosystems.com +260 C Revision 1.51 Notes 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" 3-9 AS1901, AS1902, AS1903 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 VDD = Full Range; TA = -40 to +85C; Unless Otherwise Specified Table 3. Electrical Characteristics Parameter Symbol VDD Range VDD Supply Current (AS1901/2/3) IDD Reset Threshold Voltage1 tRD Reset Active Time-Out Period3 tTP RESETN Output Voltage (AS1901) Min TA = 0 to +70C 1.0 3.6 TA = -40 to +85C 1.2 3.6 VDD = 3.3V, No Load VOL VOH VOH RESET Output Voltage (AS1902) VOL RESET Threshold Hysteresis VHYST Open-Drain RESETN Output Leakage Current (AS1903) ILEAK Typ Max Unit V 230 430 TA = +25C VTH 1.5% VTH VTH + 1.5% TA = -40 to +85C VTH 2.5% VTH VTH + 2.5% 20 50 s tTP tTP + 60% ms ISINK = 1.2mA, VDD = 2.1V, Reset Asserted 0.4 V ISINK = 400A, VDD = 1.2V, Reset Asserted 0.4 V VTH VDD to Reset Delay2 RESETN Output Voltage (AS1901/3) Conditions VDD = VTH to (VTH - 100mV) tTP 40% nA V ISOURCE = 1.2mA, VDD = 3.2V 0.8 x VDD V ISOURCE = 500A, VDD = 2.1V, Reset Asserted 0.8 x VDD V ISOURCE = 100A, VDD = 1.2V, Reset Asserted 0.8 x VDD V ISINK = 1.2mA, VDD = 3.2V, Reset Not Asserted 0.4 10 V mV 0.1 A Notes: 1 See Table 6, "Coding of Factory-Trimmed Reset Threshold Voltages," on page 6. 2 Guaranteed by design. 3 See Table 4, "Coding of Factory-trimmed Reset Active Time-Out Period," on page 6. www.austriamicrosystems.com Revision 1.51 4-9 AS1901, AS1902, AS1903 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 Figure 3. Supply Current vs. Temperature Figure 4. Power Down Reset Delay vs. Temp. 200 0.5 VOD = 10mV . 0.4 Reset Delay (s) Supply Current (mA) . 175 0.3 0.2 150 125 100 75 50 0.1 25 0 -40 -15 10 35 60 0 -40 85 Figure 5. Power-Up Reset Timeout vs. Temperature 10 35 60 85 Figure 6. Max. Trans. Duration vs. Reset Th. Overdrive 200 200 175 Max. Transient Duration (s) Power-Up Reset Timeout (ms) . . -15 Temperature(C) Temperature(C) 150 125 100 75 50 25 0 -40 175 150 125 100 75 50 25 0 -15 10 35 60 1 85 www.austriamicrosystems.com 10 100 1000 Reset Th. Overdrive VTH-VCC (mV) Temperature(C) Revision 1.51 5-9 AS1901, AS1902, AS1903 Data Sheet - D e t a i l e d D e s c r i p t i o n 8 Detailed Description Interfacing to Microprocessors with Bi-Directional Reset Pins The device has an open drain RESETN output, which enables easy interfacing to microprocessors (P) with bi-directional reset pins, such as the Motorola 68HC11. The RESETN pin of the microcontroller (C) can be connected directly to the P supervisor's RESETN output with a single pull-up resistor (see Figure 1 on page 1). Negative-Going VDD Transients The device is optimized to ignore short-duration, negative-going VDD transients (glitches) in order to avoid incorrect resets. In the graph Maximum Transient Duration vs. Reset Threshold Overdrive (page 6), the conditions are shown, for which the reset pulses are not generated. In the graph the maximum pulse width that a negative VDD transient may have when a reset signal is generated. As the amplitude of the transient increases, the maximum allowable pulse width decreases. Options Table 4. Coding of Factory-trimmed Reset Active Time-Out Period tTP in Milliseconds Device Suffix Min Typ Max AS190x_xx A 3 5 8 AS190x_xx B 12 20 32 AS190x_xx C 60 100 160 AS190x_xx D 300 500 800 Table 5. Output Variants Device Output Functionality AS1901xxx Active Low (RESETN) AS1902xxx Active High (RESET) AS1903xxx Open Drain (RESETN) Table 6. Coding of Factory-Trimmed Reset Threshold Voltages Reset Threshold Voltage, VTH in V Device Suffix TA = +25C Min Typ TA = -40 to +85C Max Min Max AS190xx__ 22 2.167 2.2 2.233 2.145 2.255 AS190xx__ 23 2.285 2.32 2.355 2.262 2.378 AS190xx__ 24 2.364 2.4 2.436 2.340 2.460 AS190xx__ 25 2.463 2.5 2.538 2.438 2.563 AS190xx__ 26 2.591 2.63 2.669 2.564 2.696 AS190xx__ 27 2.660 2.7 2.741 2.633 2.768 AS190xx__ 28 2.758 2.8 2.842 2.730 2.870 AS190xx__ 29 2.886 2.93 2.974 2.857 3.003 AS190xx__ 30 2.955 3.0 3.045 2.925 3.075 AS190xx__ 31 3.034 3.08 3.126 3.003 3.157 www.austriamicrosystems.com Revision 1.51 6-9 AS1901, AS1902, AS1903 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 device is available in a 3-pin SOT-23 package. Figure 7. 3-Pin SOT-23 Package. www.austriamicrosystems.com Revision 1.51 7-9 AS1901, AS1902, AS1903 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 device is available in the following standard versions. Standard Part Threshold Duration Marking AS1901C23 2.32 100ms ASBA AS1901C26 2.63 100ms ASBD AS1901C31 3.08 100ms ASBI AS1902C23 2.32 100ms ASBK AS1902C26 2.63 100ms ASBN AS1902C31 3.08 100ms ASBS AS1903C23 2.32 100ms ASBU AS1903C26 2.63 100ms ASBX AS1903C31 3.08 100ms ASB3 Non-standard versions require a minimum order of 30,000 units. Contact austriamicrosystems for availability of nonstandard versions. www.austriamicrosystems.com Revision 1.51 8-9 AS1901, AS1902, AS1903 Data Sheet Copyrights Copyright (c) 1997-2007, 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. 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