MIC809/810 Power Supply Undervoltage Monitor Advance Inform ation General Description The MIG809 and MIC810 are undervoltage detectors com- binec with a reset-pulse generator. They are designed for monitoring the power supply of digital circuits, particularly microcontroller or microprocessor based systems. The reset pulse output is asserted any time the input falls below the preset threshold voltage and remains asserted for 140ms minimum after the input rises above the threshold. The reset pulse is also generated at power-on. Awide choice of voltage thresholds accomodates a variety cf supply voltages and tolerances. Coniact Micrel regarding availability of voltage thresholds not listed. The MIC809 has an active-low reset output, while the MIC810 has a high-true reset output. Both devices feature a choice of complementary push-pull or open-drain outputs. Hyster- esis is included to prevent chattering due to noise. The MIC809/810 feature low supply current (typically 102A) and Features * Enhanced replacement for MAX809 and MAX810 ~ Lower quiescent Current ~ More output options * Choice of preset threshold voltages * 140ms minimum power-on reset pulse output * Aclive-high (MIC810) or active-low (MIC809) reset output * Complementary or open-drain output Reset output valid down to 1V (MIC809) * Qutput can be wire-ORed (N and P options} Low 10pA typical supply current * No external components * SOT-23-3 Package Applications * Computer systems * Consumer electronics the tiny 3-pin plastic SOT-23 package with an industry- standard pinout. Embedded controllers Power supplies Ordering Information Part Number Marking Output Temperature Range Package MIC809N-xBM3 UANx Open Drain, 40C to +85C SOT-23 Active Low MICG809L-xBM3 UALx Low True 40C to +85C SOT-23 MiC810P-xBM3 UBPx Open Drain, 40C to +85C SOT-23 Active High MIC810H-xBM3 UBHx High True 40C to +B5C SOT-23 x = threshold vollage code Typical Application Threshold Voltage Code Voc Code Supply Threshold L 5.0V +5% 4,.63V _<f M 5.0V +10% 4,.38V VCC T 3.3V 45% 3.08V VIN Micro- s 3.3V 10% 2.93V MIC809L processor A 2.85V 45% 2.63V AST reset x 3.0V 45% 2.78V GND GND X 2.75V +5% 2.54V x 2.5V t5% 2.31V } x 2.4V 45% 2.22V Xx 2.2V t5% 2.04V x 2.0V 5% 1.85V x 1.8V +5% 1.67V x = contact factory Micrel, inc. - 18469 Fortune Drive - San Jose, CA $5131 + USA - tel + 1 (408) 944-0800 - fax + 1 (408) 944-0970 - http: //www.micrel.com February 5,1998 1 MIC8&09/810 eeMIC809/810 Output Options VIN MIC809N GND N-Channel Open-Drain (Puil-Down) Output (N} VIN MIC B09L GND Complementary Output (L) Pin Configuration Micre! VIN | MIC810P GND P-Channel Open-Drain (Pull-Up) Output (P} VIN | + RST | | | | | 4 Sao oH LL , GND Com piementary Output (H) VIN 3] Uxxx a identification O Lz] GND RST SOT-23 Pin Description Pin Number Pin Name Pin Function 1 GND Ground 2 RST Reset: Digital Quiput. Active-low on MIC809; active-high on MIC810. Asserted whenever V,,, falls below the programmed threshold. Deasserted 140ms minimum after V,,, exceeds the threshold. 3 VIN Analog Input: Voltage monitor input and the IC power supply input. MIC809/810 2 February 5,1998MiIC809g/8Tt0 Micrei Absolute Maximum Ratings Operating Ratings Supply Voltage (Vip) oc eccceeecseeeecessectseseesesenesenees . Supply Voltage (Vin) -.-cceeeecevsscseccseeneeeeeaes +1.0V to +5.5V iN IN Reset Voltage (Vay) --- Ambient Temperature (T,) ~40C to +85C Reset Current (Ipaq) seescsccesceseeenecserssrernscenssesssaneess Power Dissipation (Pp at Ty = +85C) oes 320mW Storage Temperature (Tg) ....c cee 65C to +150C Lead Temperature (soldering 5 SC.) ...... eee 260C Electrical Characteristics Ving = 5.OV (L, M volt.), Vi = 3.3 (T, S volt.), Ty = 25C; bold values indicate 1.0V < V,, $ 5.5V, 40C < T, s +85C; unless noted. Symbol Parameter Condition Min Typ Max Units AV ,/At Supply Rise Rate device functional at power-on Vins lop Operating Supply Current 10 25 pA Vey Threshold Voltage -L voltage code 4.63 v V -M voltage code 4.38 v V -T voltage code 3.08 Vv V -S voltage code 2.93 v V -R voltage code 2.63 Vv Vv AV, /AT Temperature Coefficient 30 Ippm?ec tppop Propagation Delay Vin = Vry fo (Vr 100mV)} 20 ps lRESET Reset Pulse Width Twin S Ta S Tax 240 ms Voi Reset Output Voltage Low MIC809L/809N, -R/-S/-T voltage codes, Vv Vin = Vey (in), loi = 1-2mA MIC80SL/809N, -L/-M voltage codes, Vv Vin = Vey (min), Ign = 3-2mA MIC8OSL/808N, -L/-M voltage codes, 0.3 v Vin 2 1-0V, Iginge = SOMA MIC810H, -R/-S/-T voltage codes, Vv Vin = Ven ax), long = 1-2mA MIC810H, -L/-M voltage codes, Vv Vin = Vru(ax), loi = 3-2mA Von Reset Output Voltage High MIC809L, -A/-S/-T voltage codes, V Vin > Vin(ax), Isource = S0OHA MIC8OSL, -L/-M voltage codes, Vv Vin > Vru(Max), Isqunce = 80QHA MIG810H/810P, V 1.8V < Viy < Vuln), Isouace = 150HA Note 1: Final test on outgoing product is performed at T, = 25C. Device performance over temperature is guaranteed by design. February 5,1998 3 MIC809/810MiC809/870 Typical Characteristics Supply Current vs. Temperature Power-Down Reset Delay va. Temperature Micrel Power-Down Roset Delay va. Temperature 100 00 oto) 100 4--4-4-- + < Yop = Yr Min Vo = Vr Vin 3 3 3 UHH b 7 m+ a 1 z > ee | > CTTTTTT w 60 Awalting Ful 5 6o;+- Awaiting Full x 60 }+- Awalting Full +4 a Characterization i Choracterization || in Characterization a Data 5 ata a ate rT > 40 5 40 fo og t 4 ib 40 jovup ft + _f > ry Lite om PEt a uw PrP re a TYP Ty 5 20 = 20 (R, Sand T 20 {LandM -1 a VOLTAGES) 7 1 VOLTAGES) _| D 0 Lilith oti tii tt) 1 -60 -30 0 30 60 3% 120 150 -60 -30 0 30 60 90 120 150 -60 -30 0 30 60 90 120 150 TEMPERATURE (C) TEMPERATURE (C) TEMPERATURE (C} Power-Up Reset Tim sout Normelized Reaet Threshold Power-Up vs. Temperature va. Temperaiure Oulpul Response 100 100 5 ~ e oe = Yr Min = 4}-MIcses = 0 80 K3 L = 2 5 = pe > 60 Awaiting Full 2 60 Awaiting Full 24 = Characterization 8 Characterization A Awaiting Full a Data x Date 7 T- Characterization a 5 40 uw 40 4 Data a = =3 i F FE mm 20 20 2? z 21 0 0 0 -60 -30 6 30 60 90 120 150 -60 -30 0 30 60 90 120 150 0 j 2 3 4 5 TEMPERATURE (C) TEMPERATURE (C) TIME (ms) Power-Down Power-Up Power-Down Output Response Output Response Output Response 5 T 5 T 5 ~ ' = 4|_MIcgo9 S4p-MIC810 = 4LMIC810 5 3 5 3 5 3 fe . p2 2 24 i D4 ay o Awaiting Full o Awaiting Full o Awaiting Full 7 1 Characterization ~~ 7 7 Characterization ~~~ > ~ Characterization ~] 4 Data 4 Data _ 4 Data _ 23 23 23 5e 5 2 5 2 21 21 2 if-+- 0 0 i | 0 i | 0 1 2 3 4 5 oO 1 2 3 4 5 0 1 2 3 4 5 TIME {ns} TIME (ms) TIME (ms) MIC809/810 4 February 5,1998MIC809/810 Applications Information Input Transients The MIC809/810 are inherently immune to very short nega- tive-going supply glitches. In the case of very brief tran- sients, Vj may drop below the reset threshold without activating the reset output. As shown in Figure 1, the nar- rower the transient, the deeper the reset threshold overdrive that will be ignored by the MIC809/810. The graph represents the typical allowable transient duration for a given amount of threshold overdrive that will not generate a reset. Reset Comparator Overdrive va. Duration g 1000 3 4 2 25C o - 100 3 a Awaiting Full 5 Characterization w Data 2 10 < r Ez 4 = 1 0 20 40 60 80 100 VOLTAGE (mV) Figure 1. Response to Input Transients Figure 1 is derived by adding a negative-going square-wave pulse to adc V/,, of 0.5V above the actual measured threshold for the part being characterized. Bypass capacitance placed as close as possible to the VIN and GND pins will increase the transient immunity (0.12 F, forexample). Figure 2 shows the M!IC809/810 system behavior with a varying supply voltage. Vuyst fF - - - - - Vag? cmiceog) teeset Vou f ~~ Vast (MIC810) You A.Vy rate of rise should not exceed 100Vi18 per the Electrical Characteristics section. B. Very short transients will be ignored by the 41C608/810. See " Appiiaations information. . Without external pull-down or pull-up resistors, the output Is not guaranteed to be valld when Vay TV. Figure 2. System Behavior Micrel Output Topologies The MIC809 and MIC810 are available with a choice of complementary push-pull or open-drain output. The complementary push-pull outputs on the MICS09L and MICB10H have active drivers for both pulling up and pulling down. They can be connected to logic inputs without the need for pull-up or pull-down resistors. Vee o ather > open-drain, 100k iP aotive-iow q | reset signals VCC VIN Micro- MIC SOON processor sem Reset RST >) Input GND GND Ww Figure 3. MICS309N Typical Application The open-drain outputs of the MICSO9N and MIG810P have only one active driver, thatis, they can only pull down or pull up, respectively. These devices may require an external resistor to provide complementary drive (external pull-up on MIC809N and external pull-down on MIC810P). Their advan- tage is that their outputs can be directly wire-OR'ed with other open-drain logic signals. Resistor values of 10k to 100kQ are appropriate for most systems. Typical applica- tions using the MIC8O9N and MIC810P are shown in Figures 3 and 4. See additional notes regarding external pull-up or pull-down resistors in the following section. Vee Qo ather open-source, P active-high reset signals yvcc VIN Micro- mice10P processor Reset RST | input GND Fico |_GND Vv Figure 4. MIC8098P Typical Application February 5,1998 MIC809/810MIC809/810 Micrel Insuring Proper Operation at Low Supply When Vj, is below 1.0V, the MIC809's outpul driver cannot sufficiently turn on to produce a valid logic-low on its /RST output. In this situation, other CMOS circuits driven by /RST could be allowed to float, causing undesired operation. (In most cases it is expected that the circuits driven by the MIC809 will also be similarly inoperative at Voc < 1V.) Ita given application requires that (RST be valid below V,, = 1V, this can be accomplished by adding a pull-down resistor to the /RST output. See Figure 5. A value of 100kQ is recom- mended as a compromise of leakage current and pull-down current, although the resistors value is not critical. Veo oO VCC VIN Micro- MicBo9L Processor RST Plc GND $100k | GND z Vv Figure 5. Circuit for Valid Reset at Low Input Voltage Voc oa $100k [VCE VIN Micro- processor MIC810H Reset RST + input GND GND Lf Vv Figure 6. Circuit for Valid Reset at Low Input Voltage The previous statements also apply to the MIC810s RST output. That is, to insure valid RST signal levels at Vix) < 1V, a pull-up resistor (as opposed to a pull-down) should be added to the MIC810s RST output. A value of 100kQ is typical for this application as well. (See Figure 6.) Interfacing to Processors with Bidirectional Reset Pins Some microcontrollers and microprocessors have reset- signal pins that are bidirectional in nature, rather than input only. The Motorola 6BHC11 family is one example. To use the MIG809/810 with these processors, insert a resistor into the signal path between the MIC809/810 reset output and the microprocessor reset input. This prevents excessive current flow due to contention between the two drivers. Since this also limits the drive capability of the processors reset signal, itis necessary to provide a buffer to drive other circuits. See Figure 7. Veo o > to other aorcuits VOC VIN Micro- wicaos processor Reset RST Input SND GND LT Figure 7. Interfecing to Processors with Bidirectional Reset Pins MIC809/810 February 5,1998MiC809/810 Micrel! Package Information ee 6 { 1.40 (0.055} 2.50 (0.098) 1.19 (0.047) 2.10 (0.083) Oo U $ 2.36 (0.093) 2.28 (0.090) DIMENSIONS: MM (INCH) 1.15 (0.045) 267 05) 3108 0.76 (0.030) . 0.18 (0.006) oe & 0.076 (0.0030) =i i the 5 0.445 (0.0175) TYP 3 PLACES>| be O10 (0-004) SOTO BOs BOO i 0.44 (0. og) 0.13 (0.005) SOT-23 (M3) February 5,1998 7 MIG809/810MICc809/810 Micrel MICREL INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131 USA TEL + 1 (408) 944-0800 Fax + 1 (408) 944-0970 wes hitp:/Avww. micrel.com This information is believed to be accurate and reliable, however no responsibility is assumed by Micrel for its use nor for any infringement of patents or other rights of third parties resulting from its use. No license is granted by implication or otherwise under any patent or patent right of Micrel Inc. 1998 Micrel Incorporated MiIC809/810 8 February 5,1998