LM3707XQBP-308

LM3706/LM3707 Microprocessor Supervisory Circuits with Low Line Output and Watchdog Timer June 2002 LM3706/LM3707 Microprocessor Supervisory Circuits with Low Line Output and Watchdog Timer General Description The LM3706/LM3707 series of microprocessor supervisory circuits provide the maximum flexibility for monitoring power supplies and battery controlled functions in systems without backup batteries. The LM3706/LM3707 series are available in a 9-bump micro SMD package. Built-in features include the following: Reset: Reset is asserted during power-up, power-down, and brownout conditions. RESET is guaranteed down to VCC of 1.0V. Low Line Output: This early power failure warning indicator goes low when the supply voltage drops to a value which is 2% higher than the reset threshold voltage. Watchdog Timer: The WDI (Watchdog Input) monitors one of the µP’s output lines for activity. If no output transition occurs during the watchdog timeout period, reset is activated. n n n n n n n n n No external components required RESET (LM3706) or RESET (LM3707) outputs Precision supply voltage monitor Factory programmable Reset and Watchdog Timeout Delays Available in micro SMD package for minimum footprint ± 0.5% Reset threshold accuracy at room temperature ± 2% Reset threshold accuracy over temperature extremes Reset assertion down to 1V VCC (RESET option only) 28 µA VCC supply current Applications n n n n Embedded Controllers and Processors Intelligent Instruments Automotive Systems Critical µP Power Monitoring Features n Standard Reset Threshold voltage: 3.08V n Custom Reset Threshold voltages: For other voltages between 2.2V and 5.0V in 10mV increments, contact National Semiconductor Corp. Typical Application 20011603 © 2002 National Semiconductor Corporation DS200116 www.national.com LM3706/LM3707 Connection Diagram Top View (looking from the coating side) micro SMD 9 Bump Package BPA09 20011601 Pin Descriptions Bump No. B1 C1 Name VCC RESET Power Supply input. Reset Logic Output. Pulses low for tRP (Reset Timeout Period) when triggered, and stays low whenever VCC is below the reset threshold or when MR is below VMRT. It remains low for tRP after either VCC rises above the reset threshold, or after MR input rises above VMRT (LM3706 only). Reset Logic Output. RESET is the inverse of RESET (LM3707 only). Low-Line Logic Output. Early Power-Fail warning output. Low when VCC falls below VLLOT (Low-Line Output Threshold). This output can be used to generate an NMI (Non-Maskable Interrupt) to provide an early warning of imminent power-failure. Ground reference for all signals. Watchdog Input Transition Monitor: If no transition activity occurs for a period exceeding tWD (Watchdog Timeout Period), reset is engaged. No Connect. No Connect. Test input used at factory only. Leave floating. Function RESET C3 LLO B3 A3 A1, A2, C2 B2 GND WDI NC NC www.national.com 2 LM3706/LM3707 Block Diagram 20011605 3 www.national.com LM3706/LM3707 Ordering Information 20011604 *For other voltages between 2.2V and 5.0V, please contact National Semiconductor sales office. LM3706/LM3707 Part Number LM3706XQBP-308 LM3706XQBPX-308 LM3707XQBP-308 LM3707XQBPX-308 %% is the datecode and will vary with time. Output totem-pole totem-pole totem-pole totem-pole Reset Timeout Period 200ms 200ms 200ms 200ms Watchdog Timeout Period 1600ms 1600ms 1600ms 1600ms Package Marking %%I6 %%I6 %%I7 %%I7 Table Of Functions Part Number LM3706 LM3707 * = available upon request. Contact National Active Low Reset x Active High Reset x Output (X = totem-pole) (Y = open-drain) X, Y* X Reset Timeout Period Customized Customized Watchdog Timeout Period Customized Customized Low Line Output x x www.national.com 4 LM3706/LM3707 Absolute Maximum Ratings (Note 1) Power Dissipation (Note 3) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Supply Voltage (VCC) All Other Inputs ESD Ratings (Note 2) Human Body Model Machine Model −0.3V to 6.0V −0.3V to VCC + 0.3V 1.5kV 150V Operating Ratings (Note 1) Temperature Range −40˚C ≤ TJ ≤ 85˚C LM3706/LM3707 Series Electrical Characteristics Limits in the standard typeface are for TJ = 25˚C and limits in boldface type apply over full operating range. Unless otherwise specified: VCC = +2.2V to 5.5V. Symbol VCC ICC Parameter Operating Voltage Range: VCC VCC Supply Current Reset Threshold LM3706 LM3707 All inputs = VCC; all outputs floating Conditions Min 1.0 1.2 28 Typ Max 5.5 5.5 50 Units POWER SUPPLY V µA RESET THRESHOLD VRST VCC falling VCC falling: TA = 0˚C to 70˚C VRSTH tRP Reset Threshold Hysteresis Reset Timeout Period Reset Reset Reset Reset Timeout Timeout Timeout Timeout Period Period Period Period = = = = E, J, N, S F, K, P, T G, L, Q, U H, M, R, V 1 20 140 1120 −0.5 −2 −1.5 0.0032 • VRST 1.4 28 200 1600 20 2 40 280 2240 VRST +0.5 +2 +1.5 mV % ms tRD VCC to Reset Delay RESET VCC falling at 1mV/µs µs RESET (LM3707) VOL VCC > 2.25V, ISINK = 900µA VCC > 2.7V, ISINK = 1.2mA VCC > 4.5V, ISINK = 3.2mA VOH RESET VCC > 1.2V, ISOURCE = 50µA VCC > 1.8V, ISOURCE = 150µA VCC > 2.25V, ISOURCE = 300µA VCC > 2.7V, ISOURCE = 500µA VCC > 4.5V, ISOURCE = 800µA ILKG Output Leakage Current RESET VRESET = 5.5V 0.8 VCC 0.8 VCC 0.8 VCC 0.8 VCC VCC − 1.5V 1.0 µA V 0.3 0.3 0.4 V RESET (LM3706) VOL VCC > 1.0V, ISINK = 50µA VCC > 1.2V, ISINK = 100µA VCC > 2.25V, ISINK = 900µA VCC > 2.7V, ISINK = 1.2mA VCC > 4.5V, ISINK = 3.2mA VOH RESET VCC > 2.25V, ISOURCE = 300µA VCC > 2.7V, ISOURCE = 500µA VCC > 4.5V, ISOURCE = 800µA WDI 0.8 VCC 0.8 VCC VCC − 1.5V 0.3 0.3 0.3 0.3 0.4 V 5 www.national.com LM3706/LM3707 LM3706/LM3707 Series Electrical Characteristics Symbol WDI WDIT tWD Parameter Watchdog Input Current Watchdog Input Threshold Watchdog Timeout Period Watchdog Watchdog Watchdog Watchdog Timeout Timeout Timeout Timeout Period Period Period Period = = = = E, F, G, H J, K, L, M N, P, Q, R S, T, U, V Conditions (Continued) Limits in the standard typeface are for TJ = 25˚C and limits in boldface type apply over full operating range. Unless otherwise specified: VCC = +2.2V to 5.5V. Min −1 Typ Max +1 Units µA 0.2 • VCC 4.3 71 1120 17900 1.225 6.2 102 1600 25600 0.8 • VCC 9.3 153 2400 38400 0.3 0.3 0.4 V ms LLO VOL LLO Output Voltage VCC > 2.25V, ISINK = 900µA VCC > 2.7V, ISINK = 1.2mA VCC > 4.5V, ISINK = 3.2mA VOH VCC > 2.25V, ISOURCE = 300µA VCC > 2.7V, ISOURCE = 500µA VCC > 4.5V, ISOURCE = 800µA LLO OUTPUT VLLOT LLO Output Threshold (VLLO − VRST, VCC falling) Low-Line Comparator Hysteresis Low-Line Comparator Delay VCC falling at 1mV/µs 1.01 • VRST 1.02 • VRST 1.03 • VRST V 0.8 VCC 0.8 VCC VCC − 1.5V V VLLOTH 0.0032 • VRST mV tCD 20 µs Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is intended to be functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. The guaranteed specifications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the listed conditions. Note 2: The Human Body model is a 100 pF capacitor discharged through a 1.5 kΩ resistor into each pin. The machine model is a 200pF capacitor discharged directly into each pin. Note 3: The maximum allowable power dissipation is a function of the maximum junction temperature, TJ(MAX), the junction-to-ambient thermal resistance, θJ-A, and the ambient temperature, TA. The maximum allowable power dissipation at any ambient temperture is calculated using: Where the value of θJ-A for the micro SMD package is 220˚C/W. www.national.com 6 LM3706/LM3707 Typical Performance Characteristics Supply Current vs Supply Voltage 3.3V Supply Current vs Temperature 20011611 20011615 Normalized Reset Threshold Voltage vs Temperature Reset Timeout Period vs VCC 20011612 20011632 Reset Timeout Period vs Temperature Max. Transient Duration vs Reset Comparator Overdrive (VCC = 3.3V) 20011610 20011616 7 www.national.com LM3706/LM3707 Typical Performance Characteristics Watchdog Timeout Period vs Temperature (tWD programmed as 6.2ms) (Continued) Low-Line Comparator Propagation Delay vs Temperature 20011614 20011613 Circuit Information Reset Output The Reset input of a µP initializes the device into a known state. The LM3706/LM3707 microprocessor supervisory circuits assert a forced reset output to prevent code execution errors during power-up, power-down, and brownout conditions. RESET is guaranteed valid for VCC > 1V. Once VCC exceeds the reset threshold, an internal timer maintains the output for the reset timeout period. After this interval, reset goes high. The LM3706 offers an active-low RESET; The LM3707 offers an active-high RESET. Any time VCC drops below the reset threshold (such as during a brownout), the reset activates. When VCC again rises above the reset threshold, the internal timer starts. Reset holds until VCC exceeds the reset threshold for longer than the reset timeout period. After this time, reset releases. Reset Threshold The LM3706/LM3707 family is available with a reset voltage of 3.08V. Other reset thresholds in the 2.20V to 5.0V range, in steps of 10 mV, are available; contact National Semiconductor for details. Low-Line Output (LLO) The low-line output comparator is typically used to provide a non-maskable interrupt to a µP when VCC begins falling. LLO monitors VCC and goes low when VCC falls below VLLOT (typically 1.02 • VRST) with hysteresis of 0.0032 • VRST. Watchdog Timer Input (WDI) The watchdog timer input monitors one of the microprocessor’s output lines for activity. Each time a transition occurs on this monitored line, the watchdog counter is reset. However, if no transition occurs and the timeout period is reached, the LM3706/LM3707 assumes that the microprocessor has locked up and the reset output is activated. WDI is a high impedance input. Special Precautions for the micro SMD Package As with most integrated circuits, the LM3706 and LM3707 are sensitive to exposure from visible and infrared (IR) light radiation. Unlike a plastic encapsulated IC, the micro SMD package has very limited shielding from light, and some sensitivity to light reflected from the surface of the PC board or long wavelength IR entering the die from the side may be experienced. This light could have an unpredictable affect on the electrical performance of the IC. Care should be taken to shield the device from direct exposure to bright visible or IR light during operation. Micro SMD Mounting The micro SMD package requires specific mounting techniques which are detailed in National Semiconductor Application Note AN-1112. Referring to the section Surface Mount Technology (SMT) Assembly Considerations, it should be noted that the pad style which must be used with the 9-pin package is the NSMD (non-solder mask defined) type. For best results during assembly, alignment ordinals on the PC board may be used to facilitate placement of the micro SMD device. www.national.com 8 LM3706/LM3707 Timing Diagrams 20011628 FIGURE 1. LM3706 Reset Time with WDI 20011629 FIGURE 2. LLO Output 9 www.national.com LM3706/LM3707 Typical Application Circuits 20011640 FIGURE 3. LM3706 Long Delay Timer/Oscillator www.national.com 10 LM3706/LM3707 Microprocessor Supervisory Circuits with Low Line Output and Watchdog Timer Physical Dimensions unless otherwise noted inches (millimeters) NOTES: UNLESS OTHERWISE SPECIFIED 1. EPOXY COATING 2. 63Sn/37Pb EUTECTIC BUMP 3. RECOMMEND NON-SOLDER MASK DEFINED LANDING PAD. 4. PIN 1 IS ESTABLISHED BY LOWER LEFT CORNER WITH RESPECT TO TEXT ORIENTATION. REMAINING PINS ARE NUMBERED COUNTER CLOCKWISE. 5. XXX IN DRAWING NUMBER REPRESENTS PACKAGE SIZE VARIATION WHERE X1 IS PACKAGE WIDTH, X2 IS PACKAGE LENGTH AND X3 IS PACKAGE HEIGHT. 6.NO JEDEC REGISTRATION AS OF AUG.1999. 9 bump micro SMD Package NS Package Number BPA09FFB The dimensions of X1, X2 and X3 are given below X1 = 1.412mm X2 = 1.412mm X3 = 0.850mm LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: 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 labeling, can be reasonably expected to result in a significant injury to the user. National Semiconductor Corporation Americas Email: support@nsc.com National Semiconductor Europe Fax: +49 (0) 180-530 85 86 Email: europe.support@nsc.com Deutsch Tel: +49 (0) 69 9508 6208 English Tel: +44 (0) 870 24 0 2171 Français Tel: +33 (0) 1 41 91 8790 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. National Semiconductor Asia Pacific Customer Response Group Tel: 65-2544466 Fax: 65-2504466 Email: ap.support@nsc.com National Semiconductor Japan Ltd. Tel: 81-3-5639-7560 Fax: 81-3-5639-7507 www.national.com National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.