UM803 3-Pin Microprocessor Reset Circuits UM803 SOT323/SOT23-3 General Description The UM803 is a microprocessor (μP) supervisory circuit used to monitor the power supplies in μP and digital systems. It provides excellent circuit reliability and low cost by eliminating external components and adjustments when used with +5V, +3.3V, +3.0V or +2.5V powered circuits. The circuit performs a single function: it asserts a reset signal whenever the VCC supply voltage declines below a preset threshold, keeping it asserted for at least 140ms after VCC has risen above the reset threshold. Reset thresholds suitable for operation with a variety of supply voltages are available. _____________ The UM803 has an open-drain output stage. The UM803’s open-drain RESET output requires a pull-up resistor that can be connected to a voltage higher than VCC. The UM803 has an active-low _____________ RESET output. The reset comparator is designed to ignore fast transients on VCC, and the outputs are guaranteed to be in the correct logic state for VCC down to 1V. Low supply current makes the UM803 ideal for use in portable equipment. The UM803 is available in a 3-pin SOT323 and SOT23 package. Applications Features Computers Controllers Portable/Battery-Powered Equipments Intelligent Instruments Critical μP and μC Power Monitoring Automotive No External Components Power Supply Transient Immunity Guaranteed Reset Valid to VCC=+1V Precision VCC Monitoring of +2.5V, +3V, +3.3V and +5V Supplies Fully Specified Over Temperature 2μA Supply Current 140ms Minimum Power-On Reset Pulse Width Available in One Output Configuration: Open-Drain Active-Low RESET Output 3-Pin SOT323 and SOT23 Packages Wide Operation Temperature: -40°C to +85°C __________ Pin Configurations Top View GND 1 XXX M 3 3 VCC Marking Pin1 RESET 2 1 M: Month Code UM803 SOT323/SOT23-3 2 ________________________________________________________________________ http://www.union-ic.com Rev.01 Jan.2015 1/11 UM803 Ordering Information UM8 XX Z P XX: Output Type =03 Open-Drain Active Low Z: Reset Threshold (V) =L 4.63 =M 4.38 =J 4.00 =T 3.08 =S 2.93 =R 2.63 =Z 2.32 P: Package Type =S SOT23-3 =P SOT323 Typical Operating Circuit VCC VCC VCC Rpullup μP UM803 RESET RESET INPUT GND GND Pin Description Pin Number Pin Name 1 GND Function Ground _____________ 2 3 ______________ RESET VCC RESET Output remains low while VCC is below the reset threshold, and for at least 140ms after VCC rises above the reset threshold. +5V, +3.3V, +3V or +2.5V Supply Voltage ________________________________________________________________________ http://www.union-ic.com Rev.01 Jan.2015 2/11 UM803 Absolute Maximum Ratings (Note 1) Symbol VCC Parameter Supply Voltage -0.3 to +6.0 _____________ ICC IO PD TA TSTG Value RESET Input Current, VCC _____________ Output Current, RESET Rate of Rise, VCC SOT323 (Derate 2.17mW/°C above 70°C) Continuous Power Dissipation SOT23-3 (Derate 4mW/°C above 70°C) SOT323 Operating Temperature Range SOT23-3 Storage Temperature Range Lead Temperature (soldering, 10s) -0.3 to +6.0 Unit V 20 mA 20 mA 100 V/μs 174 mW 320 -40 to +125 -40 to +105 -65 to +150 +300 °C °C °C Note 1: Stresses beyond those listed under “Absolute maximum Ratings” 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 the operational sections of the specifications are not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ________________________________________________________________________ http://www.union-ic.com Rev.01 Jan.2015 3/11 UM803 Electrical Characteristics (VCC = 5V for L/M/J versions, VCC = 3.3V for T/S versions, VCC = 3V for R version, and VCC = 2.5V for Z version, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 2) Symbol Parameter Conditions Min VCC Supply Voltage Range TA=0℃ to + 70℃ 1.0 ICC Supply Current M version J version Reset Threshold T version S version R version Z version TA=+25℃ TA=-40℃ to + 85℃ TA=+25℃ TA=-40℃ to + 85℃ TA=+25℃ TA=-40℃ to + 85℃ TA=+25℃ TA=-40℃ to + 85℃ TA=+25℃ TA=-40℃ to + 85℃ TA=+25℃ TA=-40℃ to + 85℃ TA=+25℃ TA=-40℃ to + 85℃ 4.56 4.50 4.31 4.25 3.93 3.89 3.04 3.00 2.89 2.85 2.59 2.55 2.28 2.25 Reset Threshold Tempco VCC to Reset Delay tRP VOL VCC=VTH to (VTH–100mV) Reset Active Timeout Period ____________ RESET Output Voltage Low RESET Open-Drain Output Leakage Current (Note 3) Max Unit 5.5 V μA 2.0 L version VTH Typ 140 VCC=VTH min, ISINK=1.2mA, UM803T_/S_/R_/Z_ VCC=VTH min, ISINK=3.2mA, UM803L_/M_/J_ VCC>1.0V, ISINK=50μA VCC>VTH, RESET deasserted 4.63 4.38 4.00 3.08 2.93 2.63 2.32 4.70 4.75 4.45 4.50 4.06 4.10 3.11 3.15 2.96 3.00 2.66 2.70 2.35 2.38 V 150 ppm/°C 10 μs 240 560 ms 0.3 0.4 V 0.3 1 μA Note 2: Production testing done at TA = +25°C; limits over temperature guaranteed by design only. Note 3: Guaranteed by design, not production tested. ________________________________________________________________________ http://www.union-ic.com Rev.01 Jan.2015 4/11 UM803 Typical Operating Characteristics (TA = +25°C, unless otherwise noted.) Supply Current vs. Temperature (UM803R_) Power-down RESET Delay vs. Temperature (UM803R_) VCC=3.3V Power-up RESET Timeout vs. Temperature ________________________________________________________________________ http://www.union-ic.com Rev.01 Jan.2015 5/11 UM803 Detailed Description A microprocessor’s (µP’s) reset input starts the µP in a known state. The UM803 asserts reset to prevent code-execution errors during power-up, power-down, or brownout conditions. It asserts a reset signal whenever the VCC supply voltage declines below a preset threshold, keeping it asserted for at least 140ms after VCC has risen above the reset threshold. The UM803 uses an open-drain _____________ output. Connect a pull-up resistor on the UM803’s RESET output to any supply between 0 and 6V. Applications Information Negative-Going VCC Transient In addition to issuing a reset to the µP during power-up, power-down, and brownout conditions, the UM803 is relatively immune to short-duration negative-going VCC transients (glitches). Figure 1 shows typical transient duration vs. reset comparator overdrive, for which the UM803 does not generate a reset pulse. The graph was generated using a negative-going pulse applied to VCC, starting 0.5V above the actual reset threshold and ending below it by the magnitude indicated (reset comparator overdrive). The graph indicates the maximum pulse width a negative-going VCC transient can have without causing a reset pulse. As the magnitude of the transient increases (goes farther below the reset threshold), the maximum allowable pulse width decreases. Typically, for the UM803L_, UM803M_ and UM803J_, a VCC transient that goes 100mV below the reset threshold and lasts 20µs or less will not cause a reset pulse. A 0.1µF bypass capacitor mounted as close as possible to the VCC pin provides additional transient immunity. UM803T_/S_/R_/Z_ UM803L_/M_/J_ Figure 1. Maximum Transient Duration without Causing a Reset Pulse vs. Reset Comparator Overdrive Interfacing to μPs with Bidirectional Reset Pins _____________ Since the RESET output on the UM803 is open drain, this device interfaces easily with μPs that have bidirectional reset pins, such as the Motorola 68HC11. Connecting the μP supervisor’s _____________ _____________ RESET output directly to the microcontroller’s (μC’s) RESET pin with a single pull-up resistor ________________________________________________________________________ http://www.union-ic.com Rev.01 Jan.2015 6/11 UM803 allows either device to assert reset (Figure 2). UM803 Figure 2. Interfacing to μPs with Bidirectional Reset I/O ______________ UM803 Open-Drain RESET Output Allows Use with Multiple Supplies Generally, the pull-up connected to the UM803 will connect to the supply voltage that is being monitored at the IC’s VCC pin. However, some systems may use the open-drain output to level-shift from the monitored supply to reset circuitry powered by some other supply (Figure 3). Note that as _____________ the UM803’s VCC decreases below 1V, so does the IC’s ability to sink current at RESET. Also, with _____________ any pull-up, RESET will be pulled high as VCC decays toward 0. The voltage where this occurs depends on the pull-up resistor value and the voltage to which it is connected. UM803 _____________ Figure 3. UM803 Open-Drain RESET Output Allows Use with Multiple Supplies Benefits of Highly Accurate Reset Threshold Most µP supervisor circuits have reset threshold voltages between 5% and 10% below the value of nominal supply voltages. This ensures a reset will not occur within 5% of the nominal supply, but will occur when the supply is 10% below nominal. When using ICs rated at only the nominal supply ±5%, this leaves a zone of uncertainty where the supply is between 5% and 10% low, and where the reset may or may not be asserted. The UM803L_/T_/Z_ use highly accurate circuitry to ensure that reset is asserted close to the 5% limit, and long before the supply has declined to 10% below nominal. ________________________________________________________________________ http://www.union-ic.com Rev.01 Jan.2015 7/11 UM803 Package Information UM803 SOT323 Outline Drawing D Symbol E HE L1 L b PIN 1 Q1 e c e End View Side View A1 A A2 Top View D E HE b e Q1 A A1 A2 c L L1 DIMENSIONS MILLIMETERS INCHES Min Max Min Max 1.80 2.20 0.072 0.088 1.15 1.35 0.006 0.054 1.80 2.40 0.072 0.050 0.25 0.40 0.010 0.016 0.65BSC 0.026BSC 0.10 0.40 0.004 0.016 0.80 1.10 0.032 0.044 0.00 0.10 0.00 0.004 0.80 1.00 0.032 0.040 0.10 0.18 0.004 0.007 0.10 0.30 0.004 0.012 0.425TYP 0.017TYP Land Pattern 0.65 0.5 0.6 1.80 0.65 NOTES: 1. Compound dimension: 2.00×1.25; 2. Unit: mm; 3.General tolerance ±0.05mm unless otherwise specified; 4. The layout is just for reference. XXX M Tape and Reel Orientation ________________________________________________________________________ http://www.union-ic.com Rev.01 Jan.2015 8/11 UM803 UM803 SOT23-3 Outline Drawing D θ b Symbol 0.2 E E1 3 2 L1 L 1 e Top View End View A1 Side View A c A2 e1 A A1 A2 b c D E E1 e e1 L L1 θ DIMENSIONS MILLIMETERS Min Max 1.050 1.250 0.000 0.100 1.050 1.150 0.300 0.500 0.100 0.200 2.820 3.020 1.500 1.700 2.650 2.950 0.950REF 1.800 2.000 0.550REF 0.300 0.600 0° 8° INCHES Min Max 0.041 0.049 0.000 0.004 0.041 0.045 0.012 0.020 0.004 0.008 0.111 0.119 0.059 0.067 0.104 0.116 0.037REF 0.071 0.079 0.022REF 0.012 0.024 0° 8° 2.02 0.80 Land Pattern NOTES: 1. Compound dimension: 2.92×1.60; 2. Unit: mm; 3. General tolerance ±0.05mm unless otherwise specified; 4. The layout is just for reference. 1.90 XXX M Tape and Reel Orientation ________________________________________________________________________ http://www.union-ic.com Rev.01 Jan.2015 9/11 UM803 Selection Table Part Number RESET Timeout Threshold Period (V) (ms) UM803LP 4.63 240 UM803MP 4.38 240 UM803JP 4.00 240 UM803TP 3.08 240 UM803SP 2.93 240 UM803RP 2.63 240 UM803ZP 2.32 240 UM803LS 4.63 240 UM803MS 4.38 240 UM803JS 4.00 240 UM803TS 3.08 240 UM803SS 2.93 240 UM803RS 2.63 240 UM803ZS 2.32 240 Output Type Open-Drain, Active Low Open-Drain, Active Low Open-Drain, Active Low Open-Drain, Active Low Open-Drain, Active Low Open-Drain, Active Low Open-Drain, Active Low Open-Drain, Active Low Open-Drain, Active Low Open-Drain, Active Low Open-Drain, Active Low Open-Drain, Active Low Open-Drain, Active Low Open-Drain, Active Low Marking Code Package Type Shipping Qty SOT323 3000pcs/7Inch Tape & Reel SOT23-3 3000pcs/7Inch Tape & Reel VLE VME VJE VTE VSE VRE VZE 03L 03M 03J 03T 03S 03R 03Z ________________________________________________________________________ http://www.union-ic.com Rev.01 Jan.2015 10/11 UM803 IMPORTANT NOTICE The information in this document has been carefully reviewed and is believed to be accurate. Nonetheless, this document is subject to change without notice. Union assumes no responsibility for any inaccuracies that may be contained in this document, and makes no commitment to update or to keep current the contained information, or to notify a person or organization of any update. Union reserves the right to make changes, at any time, in order to improve reliability, function or design and to attempt to supply the best product possible. Union Semiconductor, Inc Add: Unit 606, No.570 Shengxia Road, Shanghai 201210 Tel: 021-51093966 Fax: 021-51026018 Website: www.union-ic.com ________________________________________________________________________ http://www.union-ic.com Rev.01 Jan.2015 11/11