austriamicrosystems AG is now ams AG 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 Data sheet AS1923 Q u a d - Vo l ta g e M i c r o p r o c e s s o r S u p e r v i s o r y C i r c u i t 1 General Description 2 Key Features Simultaneous Quad-Voltage Monitoring The AS1923 microprocessor supervisory circuit was designed to monitor up to four system supply voltages without the need for external components, and asserts a single reset if any of the monitored supply voltages drops below its reset threshold. al id Precision Factory-Trimmed Reset Threshold Options: +5.0, +3.3, +3.0, +2.5, +1.8, and -5.0V User-Adjustable Voltage Monitoring Threshold Options The AS1923 features an active-low reset output that is asserted when any of the 4 monitored voltages are below their respective reset threshold. The reset output is open-drain with a weak internal pullup (10A) to IN2. Reset remains low for a specified reset timeout period (120ms min) after all voltages have stabilized. The output is valid as long as the IN1 or IN2 input voltage remains >1V. Low Supply Current: 55A Open-Drain - AS1923A Reset Timeout Period: 120ms lv 10A Current Source Pullup - AS1923B RESET Valid to IN1 = 1V or IN2 = 1V A wide range of factory-trimmed threshold voltages are available to accommodate many different supply voltages/tolerances with minimal external component requirements. External Components not Required Factory-trimmed options are available for monitoring +5.0, +3.3, +3.0, +2.5, +1.8, and -5.0V supplies with -5% and/or -10% tolerances. The device is also available with one or two user-adjustable threshold options (via external resistor-divider network) if non-standard voltage thresholds are required. 6-pin SOT23 Package am lc s on A te G nt st il Minimal external component requirements, small size, and wide temperature range (-40 to +85C) greatly improves reliability compared to individual supervisory circuits or discrete components. Immune to Fast INx Transients Guaranteed Performance: Operating Temperature Range = -40 to +85C The AS1923 is available in an 6-pin SOT23 package. 3 Applications The device is ideal for portable and battery-powered systems, embedded controllers, intelligent instruments, automotive systems, critical CPU monitoring, and any multi-supply application. Figure 1. AS1923 - Typical Application 4 ca Monitoring Voltage 1 ni Monitoring Voltage 2 Monitoring Voltage 4 5 IN2 AS1923 6 3 RESETN RESETN CPU IN3 1 IN4 GND 2 Te ch Monitoring Voltage 3 IN1 www.austriamicrosystems.com/Supervisors/AS1923 Revision 1.01 1 - 16 AS1923 Datasheet - P i n o u t 4 Pinout Pin Assignments Figure 2. Pin Assignments (Top View) Pin Descriptions Table 1. Pin Descriptions Pin Number Pin Name 1 IN4 2 GND 5 IN2 4 IN1 am lc s on A te G nt st il RESETN 3 AS1923 al id GND 2 6 IN3 lv IN4 1 Description Input Voltage 4. See Ordering Information on page 14 for monitored voltages. Ground 3 RESETN 4 IN1 5 IN2 6 IN3 Reset Output. AS1923A (see Ordering Information on page 14) supports an external pullup resistor; AS1923B contains an internal 10A current source pullup. RESETN goes low (reset asserted) when any one of the INx voltages goes below its specified threshold. After all inputs have stabilized, RESETN remains low for at least 120ms (min) before going high. Input Voltage 1. See Ordering Information on page 14 for monitored voltages. Input Voltage 2. See Ordering Information on page 14 for monitored voltages. Note: IN2 is the power supply input for the AS1923. Te ch ni ca Input Voltage 3. See Ordering Information on page 14 for monitored voltages. www.austriamicrosystems.com/Supervisors/AS1923 Revision 1.01 2 - 16 AS1923 Datasheet - 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 Electrical Characteristics on page 4 is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Table 2. Absolute Maximum Ratings Max Units IN1, IN2 (Monitored Voltage), IN3, IN4 to GND -0.3 +7 V IN4 to GND (Device Variants M, N, O, and P, see Table 5 on page 14) -7 +0.3 V RESETN to GND -0.3 +6 V Latchup immunity Comments al id Min lv Parameter Electrical Parameters Class I Level A in accordance with EIA/JEDEC 78 Continuous Power Dissipation Continuous Power Dissipation (TAMB = +70C) mW Derate 8.7mW/C above +70C am lc s on A te G nt st il 696 Temperature Ranges and Storage Conditions Junction Temperature Storage Temperature Range -55 Package Body Temperature Humidity non-condensing C C +260 C 85 % 1 The reflow peak soldering temperature (body temperature) specified is in accordance with IPC/JEDEC J-STD-020 "Moisture/Reflow Sensitivity Classification for Non-Hermetic Solid State Surface Mount Devices". The lead finish for Pb-free leaded packages is matte tin (100% Sn). Represents a max. floor life time of unlimited Te ch ni ca Moisture Sensitive Level 5 +150 +150 www.austriamicrosystems.com/Supervisors/AS1923 Revision 1.01 3 - 16 AS1923 Datasheet - 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 VIN2 = +1V to +5.5V, Typ values @ VIN2 = +3.0V to +3.3V, TAMB = +25C (unless otherwise specified). Table 3. Electrical Characteristics Tamb Operating Temperature Range VIN2 Supply Voltage Range IINx Conditions 2, 3 Min Typ Max Units -40 85 C 1.0 5.5 V VINx = Input Threshold Voltage (Input Threshold Voltage of 1.8, 2.5, or 5V) 25 VIN2 = Input Threshold Voltage (Input Threshold 4 Voltage of 3.0 or 3.3V) 55 Input Current VINx = 0 to VIN2 5 (Input Threshold Voltage = +1.23V) 115 A -0.1 0.1 0.4 1.5 am lc s on A te G nt st il VIN1 = 1.5V (AS1923 K/L only) 40 lv Parameter al id 1 Symbol VINx = -5V (Input Threshold Voltage = -5V) Reset Threshold Voltage VTH Adjustable Threshold VTH -15 -20 VINx Decreasing, +5V (-5%) Threshold 4.50 4.63 4.75 VINx Decreasing, +5V (-10%) Threshold 4.25 4.38 4.50 VINx Decreasing, +3.3V (-5%) Threshold 3.00 3.08 3.15 VINx Decreasing, +3.3V (-10%) Threshold 2.85 2.93 3.00 VINx Decreasing, +3.0V (-5%) Threshold 2.70 2.78 2.85 VINx Decreasing, +3.0V (-10%) Threshold 2.55 2.63 2.70 VINx Decreasing, +2.5V (-10%) Threshold 2.13 2.19 2.25 VINx Decreasing, +1.8V (-10%) Threshold 1.53 1.58 1.62 VINx Increasing, -5V (+5%) Threshold -4.75 -4.63 -4.50 VINx Increasing, -5V (+10%) Threshold -4.50 -4.38 -4.25 VINx Decreasing 1.20 1.23 1.26 Threshold Voltage Temperature Coefficient Threshold Hysteresis ca VHYS Reset Delay tRP Reset Active Timeout Period 120 V 60 ppm/C 0.5 % 20 s 200 280 ms Te ch ni tRD VINx = VTH to (VTH - 50mV), All Inputs Except -5V, or VINx = VTH to (VTH + 50mV), -5V Input Only V www.austriamicrosystems.com/Supervisors/AS1923 Revision 1.01 4 - 16 AS1923 Datasheet - 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 Table 3. Electrical Characteristics (Continued) Parameter VOL 1 Output Low Voltage Conditions Min Typ VIN2 = 5V, ISINK = 2mA 0.4 VIN2 = 2.5V, ISINK = 1.2mA 0.4 VIN1 = VIN2 = 1V, ISINK = 50A VOH IOH Max V 0.4 6 Output High Voltage, Output High Source Current VIN2 > 2.55V, ISOURCE = 6A (Reset Not Asserted) 0.8 x VIN2 5 Output High Source Current VIN2 2.55V (Reset Not Asserted), VOUT 0.8 x VIN2 6 V 10 A 100% production tested at TAMB = +25C. Limits over temperature guaranteed by design. The device is powered from input IN2. The RESETN output is guaranteed to be in the correct state for IN1 or IN2 down to 1V. Monitored voltage at IN2 (+3.3V, +3.0V) is also the device power supply. Supply current split is 25A for the resistor-divider network (for the monitored voltage) and 30A for other circuits. 5. Adjustable pin only. 6. AS1923B only. am lc s on A te G nt st il lv 1. 2. 3. 4. Units al id Symbol Te ch ni ca Note: All limits are guaranteed. The parameters with min and max values are guaranteed with production tests or SQC (Statistical Quality Control) methods. www.austriamicrosystems.com/Supervisors/AS1923 Revision 1.01 5 - 16 AS1923 Datasheet - 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 noted Figure 3. IN2 Input Current vs. IN2 Input Voltage Figure 4. IN2 Input Current vs. Temperature 70 70 65 60 55 3 3.5 65 VIN2 = 3.3V 60 VIN2 = 3.0V 55 4 4.5 5 50 -40 5.5 -20 IN2 Input Voltage (V) 0 20 40 60 80 Temperature(C) Figure 5. Reset Delay vs. Reset Threshold Overdrive; VIN2 = 3.0V, IN decreasingVIN2 = 3.0V, IN decreasing 80 al id 75 lv IN2 Input Current (mA) . 80 am lc s on A te G nt st il IN2 Input Current (mA) . 85 Figure 6. Reset Timeout Periode vs. Temperature; Reset Timeout Periode (ms) Reset Delay (s) . . 225 60 40 20 0 0 200 400 600 800 1000 220 215 210 205 200 195 -40 Reset Threshold Overdrive (mV) -15 10 35 60 85 Te ch ni ca Temperature (C) www.austriamicrosystems.com/Supervisors/AS1923 Revision 1.01 6 - 16 AS1923 Datasheet - 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 7. Normalized Threshold Error vs. Temperature; VIN2 = 3.0V Normalized Threshold Error (%) . 0.1 VTH = 5.0V 0 VTH = 1.8V al id -0.1 -0.2 -0.4 -40 -20 0 20 40 60 lv -0.3 80 am lc s on A te G nt st il Temperature(C) 2V/Div VIN1 VOUT 50ms/Div Te ch ni ca 5s/Div 1V/Div 2V/Div Figure 9. Reset Active Timeout Periode; VIN2 = 3.0V 1V/Div VOUT VIN1 Figure 8. Reset Delay; VIN2 = 3.0V www.austriamicrosystems.com/Supervisors/AS1923 Revision 1.01 7 - 16 AS1923 Datasheet - D e t a i l e d D e s c r i p t i o n 8 Detailed Description The AS1923 is a very small, low-power, quad-voltage microprocessor supervisory circuit designed to maintain system integrity in multi-supply systems (see Figure 10). The device offers several factory-trimmed under-voltage threshold values that minimize or eliminate the need for external components. al id Preset voltage monitoring values of +5.0, +3.3, +3.0, +2.5, +1.8, and -5.0V (see Ordering Information on page 14) are available for a wide range of applications such as telecommunications equipment, desktop and notebook computers, high-end printers, data storage equipment, and networking equipment applications. The device is powered via the IN2 input (3.0 to 3.3V) and a reset is asserted if VIN1 or VIN2 is > 1V. For improved performance, the AS1923 was also designed to ignore fast INx transients. 4 lv Figure 10. AS1923 - Block Diagram + am lc s on A te G nt st il IN1 - IN1 5 IN2 3V 5V Pullup + 3 - RESETN Timeout (220ms) 6 IN3 + - 1 IN4 + ca - Bandgap Reference ni AS1923 ch Optional on AS1923B Only The quad-voltage monitor/reset circuitry includes an accurate bandgap reference, four precision comparators, and a series of internal trimmed resistor-divider networks to set the factory-trimmed reset threshold values. Te The resistor networks scale the specified INx reset voltages to match the internal bandgap reference/comparator voltage. User-adjustable threshold options bypass the internal resistor networks and connect directly to one of the comparator inputs (an external resistor-divider network is required for threshold matching). Each of the internal comparators has a typical hysteresis of 0.5% with respect to its reset threshold. This built-in hysteresis improves device immunity to ambient noise without significantly reducing threshold accuracy when an input sits at its specified reset voltage. Note: Threshold voltage options (fixed and adjustable) are designated by the single-letter code in the model number (see Ordering Information on page 14). www.austriamicrosystems.com/Supervisors/AS1923 Revision 1.01 8 - 16 AS1923 Datasheet - A p p l i c a t i o n I n f o r m a t i o n 9 Application Information Reset Output INx VTHL RESETN tRD tRP 90% am lc s on A te G nt st il 10% lv Figure 11. RESETN Output Timing Diagram al id The AS1923 RESETN output is asserted low when any of the monitored INx voltages drop below its specified reset threshold (above for -5V option) and remains asserted for the duration of the reset timeout period (120ms minimum) after all inputs have stabilized (Figure 11). The AS1923B output driver is driven by an internal 10A current source pullup resistor. For most applications there is no need for an external pullup resistor to interface with other logic supplies. Note: An external pullup resistor must not be connected to the AS1923B. The AS1923A supports an external pullup resistor to any voltage from 0 to +5.5V if interfaced to non-standard logic supply voltages (see Figure 12). Figure 12. Interfacing to Various Logic Supply Voltages +5V VCC 100k 3 RESETN RESETN CPU ca AS1923A 2 Te ch ni GND www.austriamicrosystems.com/Supervisors/AS1923 Revision 1.01 9 - 16 AS1923 Datasheet - A p p l i c a t i o n I n f o r m a t i o n User-Adjustable Thresholds The AS1923 provides several voltage monitoring values as well as user-adjustable reset thresholds. The threshold voltage at each adjustable INx input is typically 1.23V. To monitor a voltage >1.23V, connect a resistor-divider network to the circuit as shown in Figure 13. R1 + R2 - + VREF = 1.23V am lc s on A te G nt st il - lv VINTH al id Figure 13. Setting User-Adjustable Thresholds For the circuit shown in Figure 13, calculate R1 and R2 as: or, calculated in terms of R1: R1 + R2 V INTH = 1,23V x ------------------R2 (EQ 1) V INTH R 1 = R 2 x ---------------- - 1 1,23V (EQ 2) Note: Because the AS1923 has a guaranteed input current of 0.1A on its adjustable inputs, resistor values up to 100k can be used for R2 with <1% error. Unused Inputs ca The IN2 input must always be used for normal operation (AS1923 power-supply pin). Otherwise, in cases where one or more of the AS1923 monitoring inputs will not be used, these inputs must be tied to a supply voltage greater in magnitude than their specified threshold voltages. Notes: Te ch ni 1. For unused IN3 or IN4 applications with positive thresholds (fixed or adjustable), the inputs can be connected directly to the IN2 supply. 2. For unused IN4 options with negative thresholds, the input must be tied to a more negative supply. 3. Unused pins must not be connected to ground or allowed to float. www.austriamicrosystems.com/Supervisors/AS1923 Revision 1.01 10 - 16 AS1923 Datasheet - A p p l i c a t i o n I n f o r m a t i o n Negative Voltage Monitoring Beyond -5V The AS1923 is available with options to monitor -5V supplies using internally trimmed thresholds. In cases where monitored supplies are more negative than -5V, an external low-impedance resistor-divider network can be used as shown in Figure 14. R2 - -5V R1 + VREF = 1.23V - am lc s on A te G nt st il VINTH + lv Figure 14. Negative Voltage Monitoring Beyond -5V al id The current through the external resistor-divider should be greater than the input current for the -5V monitor options. For an input monitor current error of <1%, the resistor-divider current should be 2mA (for IIN4 = 20A max). For the circuit shown in Figure 14, calculate R1 based on the desired VINx reset threshold voltage: V INTH R 1 = R 2 x ---------------- - 1 1,23V Where: (EQ 3) R2 2.49k VINTH is the desired threshold voltage. VTH is the internal threshold voltage. For -VIN = -12V nominal: VINTH = -11.1V, VTH = -4.63V, R2 = 2.49k. Using the equation given in (EQ 3), R1 can be calculated as: Therefore, R1 = 3.48k ca - 11,1V R 1 = 2,49k x ------------------- - 1 - 4,63V Power-Supply Bypassing and Grounding ni The AS1923 is powered from the IN2 supply input. All monitor inputs are immune to fast supply transients. ch If higher immunity is required in noisy systems, connect 0.1F bypass capacitors from the IN2 input to ground (see Figure 15). Additional capacitance can be added to IN1, IN3, and IN4 to improve noise immunity at these inputs. Te Figure 15. IN2 Additional Noise Immunity 5 3.0 to 3.3V IN2 0.1F AS1923 2 GND www.austriamicrosystems.com/Supervisors/AS1923 Revision 1.01 11 - 16 AS1923 Datasheet - 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 10 Package Drawings and Markings Figure 16. 6-pin SOT23 Marking Top Marking lv al id Bottom Marking Te ch ni ca am lc s on A te G nt st il xxxx- encoded Datacode www.austriamicrosystems.com/Supervisors/AS1923 Revision 1.01 12 - 16 AS1923 Datasheet - 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 Te ch ni ca am lc s on A te G nt st il lv al id Figure 17. 6-pin SOT23 Package www.austriamicrosystems.com/Supervisors/AS1923 Revision 1.01 13 - 16 AS1923 Datasheet - O r d e r i n g I n f o r m a t i o n 11 Ordering Information The device is available as the standard products listed in Table 4. Table 4. Ordering Information Descriptiom Delivery Form Package AS1923A-BSTT-A ASJD Quad-Voltage Microprocessor Supervisory Circuit with Open Drain Output Tape and Reel 6-pin SOT23 AS1923A-BSTT-C ASJF Quad-Voltage Microprocessor Supervisory Circuit with Open Drain Output Tape and Reel AS1923A-BSTT-I ASJP Quad-Voltage Microprocessor Supervisory Circuit with Open Drain Output Tape and Reel AS1923A-BSTT-K ASJR Quad-Voltage Microprocessor Supervisory Circuit with Open Drain Output Tape and Reel AS1923A-BSTT-O ASJV Quad-Voltage Microprocessor Supervisory Circuit with Open Drain Output Tape and Reel 6-pin SOT23 AS1923A-BSTT-x* tbd Quad-Voltage Microprocessor Supervisory Circuit with Open Drain Output Tape and Reel 6-pin SOT23 tbd Quad-Voltage Microprocessor Supervisory Circuit with Internal 10A Current Source Pullup Output Tape and Reel 6-pin SOT23 AS1923B-BSTT-x* *) on request al id Marking 6-pin SOT23 6-pin SOT23 lv 6-pin SOT23 am lc s on A te G nt st il Ordering Code Note: All products are RoHS compliant. Buy our products or get free samples online at ICdirect: http://www.austriamicrosystems.com/ICdirect For further information and requests, please contact us mailto:sales@austriamicrosystems.com or find your local distributor at http://www.austriamicrosystems.com/distributor These devices are available in factory-set input voltage thresholds. Choose the desired reset threshold suffix from Table 5 and insert it instead of "x" in the part number. Table 5. Variants Suffix Guide (x) Variant (x) A 1 C D 1 E 1 F G 5.0V 3.3V 2.5V 5.0V 3.3V 2.5V 5.0V 3.3V 1.8V ni B 3.3V 5.0V 3.0V 1 5.0V 3.0V 1 5.0V 3.0V 5.0V 3.0V ch 5.0V Te H Thresholds IN2 IN3 ca IN1 1 1.8V 2 2 2.5V 2.5V 2 1.8V 1.8V www.austriamicrosystems.com/Supervisors/AS1923 2 IN4 Tolerance adjustable 10% adjustable 5% adjustable 10% adjustable 5% adjustable 10% adjustable 5% adjustable 10% adjustable 5% Revision 1.01 14 - 16 AS1923 Datasheet - O r d e r i n g I n f o r m a t i o n Table 5. Variants Suffix Guide (x) 5.0V 3.3V 2.5V 2 J 5.0V 3.3V 2.5V 2 K adjustable 3.3V 2.5V 1.8V 2 10% 5% adjustable 10% adjustable 5% L 1 adjustable 3.3V M 1 5.0V 3.0V adjustable -5.0V 10% N 1 5.0V 3.0V adjustable -5.0V 5% O 5.0V 3.3V adjustable -5.0V 10% P 5.0V 3.3V adjustable -5.0V 5% 2.5V 2 1.8V Tolerance Te ch ni ca am lc s on A te G nt st il 1. Available upon request 2. Specified for 10% tolerances al id I IN4 lv IN1 Thresholds IN2 IN3 Variant (x) www.austriamicrosystems.com/Supervisors/AS1923 Revision 1.01 15 - 16 AS1923 Datasheet Copyrights Copyright (c) 1997-2011, austriamicrosystems AG, Tobelbaderstrasse 30, 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. al id Disclaimer lv 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. ca am lc s on A te G nt st il 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. Headquarters ni Contact Information ch austriamicrosystems AG Tobelbaderstrasse 30 A-8141 Unterpremstaetten, Austria Te 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 www.austriamicrosystems.com/Supervisors/AS1923 Revision 1.01 16 - 16 Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: ams: AS1923A-BSTT-C AS1923A-BSTT-O AS1923A-BSTT-A AS1923A-BSTT-I AS1923A-BSTT-K