AS1907, AS1908 , AS1909 L o w - Vo l t a 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 t s 1 General Description 2 Key Features 3 Output Types: Push/Pull The AS1907/AS1908/AS1909 microprocessor supervisory circuits are ideal for monitoring the supply voltage of digital systems and microprocessors. RESET, Push Pull RESETN, and Open Drain RESETN Reset Threshold Range: 1.6 to 2.5V (~100mV increments) 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 preset threshold (see Ordering Information on page 9). RESET/RESETN: - Valid to VCC = 0.7V (AS1907 and AS1908) - Valid to VCC = 1.0V (AS1909) The devices are available as the standard products listed in Table 1. Reset Pulse Widths: 1, 20, and 100ms Table 1. Standard Products Supply Voltage Range: +0.7 to +3.6V Model Output Type Reset Type Supply Current Range: 2.6 to 7.0µA AS1907 Push/Pull Active-Low Power Supply Transient Immunity AS1908 Push/Pull Active-High Requires No External Components AS1909 Open-Drain Active-Low Operating Temperature Range: -40 to +125ºC 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). 3 Applications 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 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. The integrated reset comparator was specifically designed to ignore fast transients on VCC. The devices are available in a 3-pin SOT23 package. Figure 1. Application Diagrams VCC VCC VCC 3 VCC 3 VCC VCC 3 VCC 3 Microprocessor AS1907 GND 1 RESETN 2 RESET I/O GND 1 www.ams.com/Supervisors/AS1907-09 VCC 3 VCC 3 Microprocessor AS1908 GND 1 2 RESET RESET I/O GND 1 Revision 1.8 Microprocessor AS1909 GND 1 2 RESETN RESET I/O GND 1 1 - 10 AS1907/AS1908/AS1909 Datasheet - P i n A s s i g n m e n t s 4 Pin Assignments Figure 2. Pin Assignments (Top View) GND 1 AS1908/ AS1907/ AS1909 RESET, RESETN 3 VCC 2 4.1 Pin Descriptions Table 2. Pin Descriptions Pin Number Pin Name 1 GND Ground RESET 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. RESETN 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. 2 3 Description VCC www.ams.com/Supervisors/AS1907-09 Positive Supply Voltage. Connect to +0.7 to +3.6V supply. Revision 1.8 2 - 10 AS1907/AS1908/AS1909 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 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 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 Min Max Units Comments Electrical Parameters VCC to GND -0.3 +5.0 V Open-Drain RESETN -0.3 +6.0 V Push/Pull RESET, RESETN -0.3 VCC + 0.3 V Input Current (VCC) 20 mA Output Current (RESET, RESETN) 20 mA Electrostatic Discharge Electrostatic Discharge HBM ±1 kV Norm: MIL 883 E Method 3015 320 mW 3-pin SOT23 derate 4mW/ºC above +70ºC +150 ºC +150 ºC Continuous Power Dissipation Continuous Power Dissipation (TAMB = +70ºC) Temperature Ranges and Storage Conditions Junction Temperature Storage Temperature Range -55 Package Body Temperature Humidity non-condensing Moisture Sensitive Level www.ams.com/Supervisors/AS1907-09 8 +260 ºC 85 % 1 The reflow peak soldering temperature (body temperature) specified is in accordance with IPC/JEDEC J-STD-020 “Moisture/Reflow Sensitivity Classification for NonHermetic Solid State Surface Mount Devices”. The lead finish for Pb-free leaded packages is matte tin (100% Sn). Represents a maximum floor life time of unlimited Revision 1.8 3 - 10 AS1907/AS1908/AS1909 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 VCC = Full Range, TAMB = -40 to +125ºC (unless otherwise specified). Typ values are at VCC = +3.0V, TAMB = +25ºC. All limits are guaranteed. The parameters with min and max values are guaranteed with production tests or SQC (Statistical Quality Control) methods. Table 4. Electrical Characteristics Symbol Parameter Conditions TAMB = 0 to +85ºC VCC Supply Voltage Range TAMB = -40 to +85ºC Min VTH tRD tTP Supply Current 1 RESET Threshold Voltage VCC Falling Reset Delay RESET Active Time-Out Period VOL RESETN Output Low Voltage; RESET asserted (AS1907/AS1909) VOH RESETN Output High Voltage; RESET Not Asserted (AS1907) VOH RESET Output Voltage; RESET Asserted (AS1908) VOL RESET Output Voltage; RESET Not Asserted (AS1908) ILEAK RESETN Output Leakage Current; RESETN Deasserted (AS1909) Max AS1907, AS1908 0.7 3.6 AS1909 1.0 3.6 AS1907, AS1908 0.78 3.6 AS1909 1.2 3.6 TAMB = -40 to +125ºC ICC Typ 1.2 Unit V 3.6 VCC = 1.8V, no load 2.4 6.0 VCC = 2.5V, no load 2.6 7.0 µA TAMB = +25ºC VTH 0.9% VTH VTH + 0.9% V TAMB = 0ºC to +50°C; AS1909C17, AS1909C168, AS1909C188 only VTH 1.2% VTH VTH + 1.2% V TAMB = -40 to +125ºC VTH 3% VTH VTH + 3% V 1 1.5 VCC falling at 10V/ms AS190x-Azz-T 33 µs 2 AS190x-Bzz-T 20 30 40 AS190x-Czz-T 100 150 200 ISINK = 50µA, VCC ≥ 1.0V 0.4 ISINK = 500µA, VCC ≥ 1.8V 0.3 ISOURCE = 200µA, VCC ≥ 1.8V 0.8 x VCC ISOURCE = 500µA, VCC ≥ 2.7V 0.8 x VCC ISOURCE = 1µA, VCC ≥ 1.0V 0.8 x VCC ISOURCE = 200µA, VCC ≥ 1.8V 0.8 x VCC ms V V V ISINK = 500µA, VCC ≥ 1.8V 0.3 ISINK = 1.2mA, VCC ≥ 2.7V 0.3 VCC > VTH 0.5 V µA 1. Not valid if VCC = VTH. www.ams.com/Supervisors/AS1907-09 Revision 1.8 4 - 10 AS1907/AS1908/AS1909 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 = +25ºC (unless otherwise specified). Figure 4. Supply Current vs. Supply Voltage 3.2 6 3 5 Supply Current (µA) . Supply Current (µA) . Figure 3. Supply Current vs. Temperature VCC = 2.5V 2.8 2.6 VCC = 1.8V 2.4 3 2 1 2.2 2 -50 4 0 -25 0 25 50 75 100 1.4 125 1.8 2.2 2.6 3 3.4 3.8 Supply Voltage (V) Temperature (°C) Figure 5. Normalized Reset Timeout Period vs. Temperature, VTH = 2.3VReset Asserted Figure 6. Output Voltage Low vs. Temperature 1.3 Output Voltage Low (mV) Norm. Reset Timeout Period . . 75 1.2 1.1 1 0.9 -50 -25 0 25 50 75 100 125 65 55 45 VCC = 2.2V ISINK = 500µA 35 25 15 5 -50 Temperature (°C) www.ams.com/Supervisors/AS1907-09 VCC = 1.8V ISINK = 500µA VCC = 0.7V ISINK = 50µA VCC = 1.0V ISINK = 50µA -25 0 25 50 75 100 125 Temperature (°C) Revision 1.8 5 - 10 AS1907/AS1908/AS1909 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. Max. Transient Duration vs. Reset Comparator OverdriveTemperature Figure 8. VCC falling Propagation Delay vs. 140 600 120 . Propagation Delay (µs) Max. Transient Duration (µs) . 700 500 400 Reset Occurs 300 Reset does not Occur 200 100 0 0.1 1 10 100 80 60 40 VCC falling at 10V/ms 20 0 -50 1000 VCC falling at 1V/ms 100 -25 Reset Comparator Overdrive (mV) 80 . Output Voltage Low (mV) . Output Voltage Low (mV) 50 75 100 125 Figure 10. Output Voltage Low vs. VCC, ISINK = 100µA Temp = -40°C Temp = +25°C Temp = +85°C Temp = +125°C 50 25 Temperature (°C) Figure 9. Output Voltage Low vs. VCC, ISINK = 50µA 60 0 40 30 20 10 0 Temp = -40°C Temp = +25°C Temp = +85°C Temp = +125°C 70 60 50 40 30 20 10 0 0.7 1 1.3 1.6 1.9 2.2 0.7 VCC (V) 1 1.3 1.6 1.9 2.2 VCC (V) Figure 11. Output Voltage Low vs. VCC, ISINK = 500µA 250 Output Voltage Low (mV) . Temp = -40°C Temp = +25°C Temp = +85°C Temp = +125°C 200 150 100 50 0 0.7 1 1.3 1.6 1.9 2.2 VCC (V) www.ams.com/Supervisors/AS1907-09 Revision 1.8 6 - 10 AS1907/AS1908/AS1909 Datasheet - 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 8.1 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. 8.2 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 100kΩ 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 100kΩ 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 = +25ºC TAMB = -40 to +125ºC Suffix Min Typ Max Min Max 25 2.478 2.50 2.523 2.43 2.58 24 2.378 2.40 2.422 2.33 2.47 23 2.279 2.30 2.321 2.23 2.37 22 2.180 2.20 2.220 2.13 2.27 21 2.081 2.10 2.119 2.04 2.18 20 1.982 2.00 2.018 1.94 2.06 19 1.883 1.90 1.917 1.84 1.96 18 1.784 1.80 1.816 1.75 1.85 17 1.685 1.70 1.715 1.65 1.75 16 1.586 1.60 1.614 1.55 1.65 8.3 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). 8.4 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.ams.com/Supervisors/AS1907-09 Revision 1.8 7 - 10 AS1907/AS1908/AS1909 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 9 Package Drawings and Markings Figure 12. 3-pin SOT23 Package Top Marking Bottom Marking xxxx- encoded Datacode www.ams.com/Supervisors/AS1907-09 Revision 1.8 8 - 10 AS1907/AS1908/AS1909 Datasheet - 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 standard products shown in Table 6. Table 6. Ordering Information Ordering Code Marking Reset Type Reset Threshold Minimum Reset Timeout Delivery Form AS1908C18-T ASHU Active High 1.8V 100ms Tape and Reel AS1908C20-T ASHV Active High 2.0V 100ms Tape and Reel AS1907C16-T ASHP Active Low 1.6V 100ms Tape and Reel AS1907C18-T ASHQ Active Low 1.8V 100ms Tape and Reel AS1907C20-T ASHR Active Low 2.0V 100ms Tape and Reel AS1907C22-T ASNB Active Low 2.2V 100ms Tape and Reel AS1907B23-T ASHX Active Low 2.3V 20ms Tape and Reel AS1909C16-T ASHY Open Drain 1.6V 100ms Tape and Reel AS1909C168-T ASSB Open Drain 1.68V 100ms Tape and Reel AS1909C17-T ASHZ Open Drain 1.7V 100ms Tape and Reel AS1909C18-T ASND Open Drain 1.8V 100ms Tape and Reel AS1909C188-T ASTE Open Drain 1.88V 100ms Tape and Reel AS1909C20-T ASH1 Open Drain 2.0V 100ms Tape and Reel AS1909C22-T ASNC Open Drain 2.2V 100ms Tape and Reel AS1909C23-T ASH2 Open Drain 2.3V 100ms Tape and Reel Non-standard versions require a minimum order of 30,000 units. Contact ams AG for availability of non-standard versions. Table 7. Coding of Factory-Trimmed Reset Active Time-Out Period Device Suffix AS1907xyy-T* AS1908xyy-T* AS1909xyy-T* A tTP in Milliseconds Min Typ Max 1 1.5 2 B 20 30 40 C 100 150 200 * 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. Note: All products are RoHS compliant and ams green. Buy our products or get free samples online at www.ams.com/ICdirect Technical Support is available at www.ams.com/Technical-Support For further information and requests, email us at [email protected] (or) find your local distributor at www.ams.com/distributor www.ams.com/Supervisors/AS1907-09 Revision 1.8 9 - 10 AS1907/AS1908/AS1909 Datasheet Copyrights Copyright © 1997-2013, ams 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. 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