Impala Linear Corporation ILC811/ILC812 October 1999 Microprocessor Reset Circuits General Description Features The ILC811/ILC812 is a low cost microprocessor supervisory circuit that asserts a reset if the power supply drops below a designated threshold or the manual reset pin is forced low. Several different reset thresholds are available to accommodate systems operating at 3 V, 3.3 V or 5 V. u Precision Voltage Monitor for 3 V, 3.3 V or 5 V Power The ILC811 has an active low RESET output, while the ILC812 offers an active high RESET output. The reset output is guaranteed to remain asserted for a minimum of 140 ms after VCC has risen above the designated reset threshold. The ILC811/ILC812 is available in a 4-pin SOT-143 package. Supplies u 6 µA Supply Current u 140 ms Minimum Reset Pulse Width u RESET Remains Valid with VCC as Low as 1.4V u Active Low Manual Reset Input u No External Components u 4-Pin SOT-143 Package Applications u Critical Microprocessor Power Monitoring u Portable Equipment u Intelligent Instruments u Computers & Printers u Controllers Typical Circuit Ordering Information VCC VCC VCC ILC811 ILC812 µP MR Top View 4 VCC RESET 2 ILC811_U 4-Lead SOT-143 -40°C to +85°C ILC812_U 4-Lead SOT-143 -40°C to +85°C Device Suffix 4.63 L 4.38 M 4.00 J 3.08 T 2.93 S 2.63 R 4 VCC GND 1 ILC811 Temp. Range Reset Threshold Voltage (V) Pin - Package Configurations GND 1 Package Place the device suffix of desired reset threshold voltage from the table below in the blank to complete the part number. RESET INPUT RESET (RESET) Part ILC812 3 MR Impala Linear Corporation RESET 2 3 MR (408) 730-3778 www.impalalinear.com 1 ILC811/ILC812 Microprocessor Reset Circuits October 1999 Absolute Maximum Ratings Parameter Symbol Ratings Units VCC -0.3 to 6.0 V Terminal Voltage Input Current Output Current MR -0.3 to (VCC + 0.3) V VCC, MR 20 mA RESET, RESET Rate of Rise Operating Temperature Range 20 mA VCC 100 V/µs TA -40 to +85 °C Storage Temperature Range -65 to +150 °C Lead Temperature (Soldering - 10 sec.) 300 °C Power Dissipation (TA = +70°C) 320 mW Stresses above those listed under ABSOLUTE MAXIMUM RATINGS may cause permanent device failure. Functionality at or above these limits is not implied. Exposure to absolute maximum ratings for extended periods may affect device reliability. Operating ranges define those limits between which the functionality of the device is guaranteed. Electrical Characteristics VCC = 5V for ILC81_L/M/J, VCC = 3.3V for ILC81_S/T, VCC = 3V for ILC81_R, TA = Operating Temperature Range, unless otherwise noted. Parameter Conditions Operating Voltage Range, VCC TA = 0°C to 70°C TA = -40°C to 85°C Supply Current, ICC ILC811L/M/J, ILC812L/M/J VCC < 3.6V, ILC811R/S/T, ILC812R/S/T Reset Voltage Threshold, VTH ILC811L, ILC812L ILC811M, ILC812M ILC811J, ILC812J ILC811T, ILC812T ILC811S, ILC812S ILC811R, ILC812R ISource = 800 µA, ILC811L/M/J ISource = 500 µA, ILC811R/S/T RESET Output Voltage, VOL VCC = VTH Min., ISink = 3.2 mA, ILC811L/M/J VCC = VTH Min., ISink = 1.2 mA, ILC811R/S/T VCC > 1.4 V, ISink = 50 µA, TA = 0°C to 70°C VCC > 1.6 V, ISink = 50 µA, TA = -40°C to 85°C RESET Output Voltage, VOH 1.8V < VCC < VTH Min., ISource = 150 µA RESET Output Voltage, VOL ISink = 3.2mA, ILC812L/M/J ISink = 1.2mA, ILC812R/S/T MR Minimum Pulse Width Max Units 5.5 5.5 V 9 6 15 10 µA 4.50 4.25 3.89 3.00 2.85 2.55 4.63 4.38 4.00 3.08 2.93 2.63 4.75 4.50 4.10 3.15 3.00 2.70 V 140 240 560 ms VCC – 1.5 0.8 x VCC V 0.4 0.3 0.3 0.3 0.8 x VCC 10 VCC > VTH Max., ILC81_L/M/J ILC81_R/S/T MR Input Threshold, VIL VCC > VTH Max., ILC81_L/M/J ILC81_R/S/T MR Pull-Up Resistance MR Glitch Immunity µs 2.3 0.7 x VCC 10 V 20 0.8 0.25 x VCC V 30 kΩ 100 (408) 730-3778 V µs 0.5 MR Input Threshold, VIH V V 0.4 0.3 MR to Reset Delay Impala Linear Corporation Typ 1.4 1.6 Reset Timeout Period, tR RESET Output Voltage, VOH Min www.impalalinear.com ns 2 ILC811/ILC812 Microprocessor Reset Circuits October 1999 Pin Functions Pin Name Pin Number ILC811 ILC812 1 1 GND Description Ground Pin. RESET 2 N/A RESET goes low if VCC falls below the reset threshold and remains asserted for one reset timeout period (140 ms min.) after VCC exceeds the reset threshold. RESET N/A 2 RESET goes high if VCC falls below the reset threshold and remains asserted for one reset timeout period (140ms min.) after VCC exceeds the reset threshold. MR 3 3 Manual reset input. A logic low on MR forces a reset. The reset will remain asserted as long as MR is held low and for one reset timeout period (140 ms min.) after MR goes high. This input can be shorted to ground via a switch or driven from CMOS or TTL logic. Float if unused. VCC 4 4 Power supply input, 3 V, 3.3 V or 5 V. Circuit Description Microprocessor Reset The RESET pin is asserted whenever VCC falls below the reset threshold voltage or if MR (manual reset) is forced low. The reset pin remains asserted for a period of 240 ms after VCC has risen above the reset threshold voltage or MR has returned high. The reset function ensures the microprocessor is properly reset and powers up into a known condition after a power failure. RESET will remain valid with VCC as low as 1.4V. VCC 4 Reset Threshold (V) MR + Reset Generator 2 3 RESET (ILC811) RESET (ILC812) 1 GND VCC V TH RESET Valid to 0V A resistor can be added from the RESET pin to ground to ensure the RESET output remains low with VCC down to 0V. A 100 kΩ resistor connected from RESET to ground is recommended. The size of the resistor should be large enough to not load the RESET output and small enough to pull-down any stray leakage currents. MR tR tR RESET VCC Transients VCC The ILC811/ILC812 are relatively immune to negative-going VCC glitches below the reset threshold. Typically, a negativegoing transient 125 mV below the reset threshold with a duration of 50 µs (25 µs for ILC81_R/S/T) or less will not cause an unwanted reset. VCC VCC ILC811 Interfacing to Bidirectional Reset Pins The ILC811/ILC812 can interface with µPs with bidirectional reset pins by connecting a 4.7 kΩ resistor in series with the ILC811/ILC812 output and the µP reset pin. µP RESET RESET 100K Figure 3: RESET Valid to VCC = 0 V Impala Linear Corporation (408) 730-3778 www.impalalinear.com 3 ILC811/ILC812 Microprocessor Reset Circuits October 1999 Alternate Source Cross Reference Guide Device Marking information Industry P/N ILC Direct Replacement KJXX ILC811J MAX811JEUS-T ILC811JU KLXX ILC811L MAX811LEUS-T ILC811LU KMXX ILC811M MAX811MEUS-T ILC811MU KRXX ILC811R MAX811REUS-T ILC811RU KSXX ILC811S MAX811SEUS-T ILC811SU KTXX ILC811T MAX811TEUS-T ILC811TU LJXX ILC812J MAX812JEUS-T ILC812JU LLXX ILC812L MAX812LEUS-T ILC812LU LMXX ILC812M MAX812MEUS-T ILC812MU LRXX ILC812R MAX812REUS-T ILC812RU LSXX ILC812S MAX812SEUS-T ILC812SU LTXX ILC812T MAX812TEUS-T ILC812TU XX = Lot Code Impala Linear Corporation (408) 730-3778 www.impalalinear.com 4 ILC811/ILC812 Microprocessor Reset Circuits October 1999 Packaging Information U Package, 4-Pin SOT-143 Small-Outline Transistor Package 0.079 0.071 0.098 0.083 0.055 0.047 0.037 0.030 0.021 0.015 0.120 0.105 0.0059 0.0035 0.040 0.031 0.080 0.070 0-8° 0.004 0.001 0.010 0.005 Dimensions are in inches. Tape and Reel Information 4.0±0.1 Ø1.5±0.1 1.75±0.1 2.0±0.05 3.5±0.05 8.0±0.3 4.0±0.1 Ø1.1±0.1 2.7±0.1 1.2±0.1 3.1±0.1 Dimensions are in millimeters. Devices sold by Impala Linear Corporation are covered by the warranty and patent indemnification provisions appearing in its Terms of Sale only. Impala Linear Corporation 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. Impala Linear Corporation makes no warranty of merchantability or fitness for any purpose. Impala Linear Corporation reserves the right to discontinue production and change specifications and prices at any time and without notice. This product is intended for use in normal commercial applications. Applications requiring an extended temperature range, unusual environmental requirements, or high reliability applications, such as military and aerospace, are specifically not recommended without additional processing by Impala Linear Corporation. Life Support Policy Impala Linear Corporation’s products are not authorized for use as critical components in life support devices or systems. 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and whose failure to perform, when properly used in accordance with instructions for use provided in the labelling, can be reasonably expected to result in a significant injury to the user. 2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. Impala Linear Corporation assumes no responsibility for the use of any circuitry other than circuitry embodied in an Impala Linear Corporation product. No other circuits, patents, licenses are implied. Impala Linear Corporation (408) 730-3778 www.impalalinear.com 5