UM706xS/UM708xS/UM813xS Supply Voltage Supervisor w/Watchdog Input and Manual Reset UM706xS SOP8 UM708xS SOP8 UM813xS SOP8 General Description The UM706xS/UM708xS/UM813xS series are cost effective system power supply supervisory circuits designed to monitor the power supplies in digital systems. The UM706xS provides power-supply monitoring circuitry that generates a reset output during power-up, power-down, and brownout conditions. The reset output remains operational with VCC as low as 1V. Independent watchdog monitoring circuitry is also provided. This is activated if the watchdog input has not been toggled within 1.6 seconds. In addition, there is a 1.25V threshold detector for power-fail warning, low battery detection, or to monitor an additional power supply. An active low debounced manual reset input is also included. The UM708xS is the same as the UM706xS, except an active-high reset is substituted for the watchdog timer. The UM813xS is the same as the UM706xS, except RESET is provided instead _____________ of RESET. All parts are available in a small outline SOP8 package. Applications Features Applications Using DSPs, Microcontrollers or Microprocessors Programmable Controls Computers Embedded Systems Industrial Equipments Intelligent Instruments Wireless Communications Systems Pin Configurations Wide Operation Voltage Range of 1V to 5.5V Correct Logic Output Guaranteed to VCC=1.0V Precision Supply-Voltage Monitor: 2.63V, 2.93V, 3.08V, 4.38V, 4.63V 200ms Reset Pulse Width Independent Watchdog Timer-1.6s Timeout (UM706xS, UM813xS) Active-High Reset Output (UM708xS, UM813xS) Voltage Monitor for Power-Fail or Low-Battery Warning Temperature Range: -40°C to +85°C Supply Current of 80μA (Typ.) Top View 8 MR 1 8 WDO VCC 2 7 RESET GND 3 6 WDI 4 5 PFO PFI UM706xS 7 6 5 UM706 XS XX 1 2 3 4 XX: Week Code UM706xS SOP8 ________________________________________________________________________ http://www.union-ic.com Rev.05 Mar.2015 1/17 UM706xS/UM708xS/UM813xS Pin Configurations Top View 8 MR 1 8 RESET VCC 2 7 RESET GND 3 6 NC 4 5 PFO PFI 6 5 UM708 XS XX 1 2 3 4 XX: Week Code UM708xS SOP8 UM708xS 8 MR 1 8 WDO VCC 2 7 RESET GND 3 6 WDI 4 5 PFO PFI 7 7 6 5 UM813 XS XX 1 2 3 4 XX: Week Code UM813xS SOP8 UM813xS Ordering Information Part Number UM706LS UM706MS UM706TS UM706SS UM706RS UM708LS UM708MS UM708TS UM708SS UM708RS UM813LS UM813MS UM813TS UM813SS UM813RS Top Marking UM706LS UM706MS UM706TS UM706SS UM706RS UM708LS UM708MS UM708TS UM708SS UM708RS UM813LS UM813MS UM813TS UM813SS UM813RS RESET Threshold (V) 4.63 4.38 3.08 2.93 2.63 4.63 4.38 3.08 2.93 2.63 4.63 4.38 3.08 2.93 2.63 Timeout Period (ms) 240 240 240 240 240 240 240 240 240 240 240 240 240 240 240 Package Type SOP8 ________________________________________________________________________ http://www.union-ic.com Rev.05 Mar.2015 2/17 UM706xS/UM708xS/UM813xS Typical Application Circuit Vcc μP Vcc Vcc RESET RESET WDI I/O PFI WDO NMI MR PFO INT UM706 PUSHBUTTON SWITCH Figure 1. UM706xS Application Circuit Vcc μP Vcc Vcc PFI RESET RESET RESET RESET UM708 MR PFO INT PUSHBUTTON SWITCH Figure 2. UM708xS Application Circuit Vcc μP Vcc Vcc RESET RESET WDI I/O PFI WDO NMI MR PFO INT UM813 PUSHBUTTON SWITCH Figure 3. UM813xS Application Circuit ________________________________________________________________________ http://www.union-ic.com Rev.05 Mar.2015 3/17 UM706xS/UM708xS/UM813xS Pin Description Pin Number Pin Name Function MR Manual-Reset Input triggers a reset pulse when pulled below 0.8V. This active-low input has an internal 250μA pull-up current. It can be driven from a TTL or CMOS logic line as well as shorted to ground with a switch. 2 VCC Supply Input 3 GND Ground Reference for all signals. 1 _______ Power-Fail Voltage Monitor Input. When PFI is less 4 5 _________ PFI than 1.25V, PFO goes low. Connect PFI to GND or VCC when not used. Power-Fail Output goes low and sinks current when PFI _________ PFO _________ is less than 1.25V; otherwise PFO stays high. Watchdog Input. If WDI remains either high or low for 1.6sec, the internal watchdog timer runs out and the __________ 6 UM706, UM813 WDI UM708 NC UM706, UM708 ______________ RESET WDO goes low. Floating WDI or connecting WDI to a high-impedance three-state buffer disables the watchdog feature. The internal watchdog timer clears whenever reset is asserted, WDI is three-stated, or WDI sees a rising or falling edge. No Connect Active-Low Reset Output pulses low for 200ms when trigged, and stays low whenever VCC is below the reset threshold. It remains low for 200ms after VCC rises ________ above the reset threshold or M R goes from Low to High. 7 ____________ Active-High Reset Output is the inverse of RESET . UM813 RESET ____________ Whenever RESET is high, RESET is low, and vice versa. Watchdog Output pulls low when the internal watchdog timer finishes its 1.6sec count and does not go high ___________ UM706, UM813 ___________ WDO again until the watchdog is cleared. WDO also goes low during low-line conditions. Whenever VCC is below ___________ the reset threshold, WDO stays low; however, unlike ______________ ___________ RESET , WDO does not have a minimum pulse width. 8 ___________ As soon as VCC rises above the reset threshold, WDO goes high with no delay. ____________ Active-High Reset Output is the inverse of RESET . UM708 RESET ____________ Whenever RESET is high, RESET is low, and vice versa. ________________________________________________________________________ http://www.union-ic.com Rev.05 Mar.2015 4/17 UM706xS/UM708xS/UM813xS Absolute Maximum Ratings (Note 1) Symbol VCC Parameter Supply Voltage ____________ ICC IO RESET, RESET (push-pull) Input Current, VCC Value Unit -0.3 to +6.0 V -0.3 to VCC +0.3 V 20 mA ____________ Output Current, RESET, RESET Rate of Rise, VCC 20 mA 100 V/μs PD Continuous Power Dissipation 471 mW TJ Operating Junction Temperature -40 to +105 °C Storage Temperature Range -65 to +150 °C TSTG Lead Temperature (soldering, 10s) 300 °C Note 1: Stresses beyond those listed under “Absolute maximum Ratings” may cause permanent damage to the device. Electrical Characteristics VCC = full range, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA =+25°C, VCC = 5V for L/M versions, VCC = 3.3V for T/S versions, and VCC = 3V for R version. (Note 2) Symbol Parameter VCC VCC Range ICC Supply Current Conditions Min. TA=0℃ to + 70℃ 1.0 5.5 TA=-40℃ to + 85℃ 1.2 5.5 TA=-40℃ to + 85℃ UM706L/ UM708L/UM813L UM706M/ UM708M/UM813M VTH Reset Threshold UM706T/ UM708T/UM813T UM706S/ UM708S/UM813S UM706R/ UM708R/UM813R TA=+25℃ 4.56 TA=-40℃ to + 85℃ 4.50 TA=+25℃ 4.31 TA=-40℃ to + 85℃ 4.25 TA=+25℃ 3.04 TA=-40℃ to + 85℃ 3.00 TA=+25℃ 2.89 TA=-40℃ to + 85℃ 2.85 TA=+25℃ 2.59 TA=-40℃ to + 85℃ 2.55 Reset Threshold Hysteresis tRS Reset Pulse Width Typ. Max. 80 150 4.63 4.70 V μA 4.75 4.38 4.45 4.50 3.08 3.11 V 3.15 2.93 2.96 3.00 2.63 2.66 2.70 40 140 Unit 200 mV 280 ms Note 2: Production testing done at TA = +25°C; limits over temperature guaranteed by design only. ________________________________________________________________________ http://www.union-ic.com Rev.05 Mar.2015 5/17 UM706xS/UM708xS/UM813xS Electrical Characteristics (Continued) VCC = full range, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA =+25°C, VCC = 5V for L/M versions, VCC = 3.3V for T/S versions, and VCC = 3V for R version. (Note 2) Symbol Parameter _____________ VOL RESET /RESET Output Voltage Low _____________ VOH tMR RESET /RESET Output Voltage High Conditions Min. Typ. ISINK=1.2mA, (for R/S/T versions) ISINK=3.2mA, (for L/M versions) VCC = 1.2V, ISINK = 100µA ISOURCE = 800µA _______ _______ MR Pull-Up Current _______ MR Pulse Width MR =0V Max. Unit 0.3 0.4 V 0.3 VCC-1.5 100 150 V 250 600 µA ns 0.8 V _______ MR Input Threshold, Low _______ MR Input Threshold, High 2.0 V _______ tMD MR to Reset Out Delay PFI Input Threshold PFI Input Current ________ PFO Output Voltage VCC=5V ISOURCE=800µA ISINK=3.2mA Watchdog function for UM706/UM813 Watchdog Timeout tWD Period tWP WDI Pulse Width VIL=0.4V, VIH=0.8Vcc WDI Input Threshold VCC=5V Low WDI Input Threshold VCC=5V High WDI=VCC WDI Input Current WDI=0V WDO Output Voltage ISOURCE=800µA High WDO Output Voltage ISINK=1.2mA Low 1.20 -25 Vcc-1.5 1.25 0.01 250 1.30 +25 0.4 1.0 1.6 2.25 50 V s ns 0.8 3.5 -150 ns V nA V V 50 -50 150 Vcc-1.5 µA V 0.4 V Note 2: Production testing done at TA = +25°C; limits over temperature guaranteed by design only. ________________________________________________________________________ http://www.union-ic.com Rev.05 Mar.2015 6/17 UM706xS/UM708xS/UM813xS Block Diagram WDI WATCHDOG TRANSITION DETECTOR 6 WATCHDOG TIMER 8 WDO TIMEBASE FOR RESET AND WATCHDOG VCC 250μA MR 1 RESET GENERATOR VCC 2 7 RESET/ (RESET)* + VREF PFI 4 + 5 PFO 1.25V 3 GND Figure 4. UM706xS/UM813xS Block Diagram (RESET)* for UM813xS 8 RESET VCC 250μA MR 1 RESET GENERATOR VCC 2 7 RESET + VREF PFI 4 + 5 PFO 1.25V 3 GND Figure 5. UM708xS Block Diagram ________________________________________________________________________ http://www.union-ic.com Rev.05 Mar.2015 7/17 UM706xS/UM708xS/UM813xS Typical Operating Characteristics _______________ _______________ RESET Output Voltage vs. Supply Voltage RESET Response Time (a) (b) 2V/div VCC VCC 2V/div 2V/div _____________ RESET 2V/div _____________ RESET 1μs/div 500ms/div Power-Fail Comparator Assertion Response Time Power-Fail Comparator De-assertion Response Time (c) 2V/div (d) ________ PFO 2V/div ________ PFO 1V/div 1V/div PFI PFI 200ns/div VCC 200ns/div 2kΩ VCC RESET VCC 10kΩ VCC RESET RESET RESET 30pF 330pF GND GND (a) (b) +5V +5V PFI 1kΩ + PFI + PFO PFO - 30pF +1.25V (c) 30pF 1kΩ +1.25V (d) ________________________________________________________________________ http://www.union-ic.com Rev.05 Mar.2015 8/17 UM706xS/UM708xS/UM813xS Typical Operating Characteristics RESET Output Voltage vs. Supply Voltage RESET Response Time (e) 2V/div VCC (e) 2V/div VCC 2V/div RESET RESET 2V/div 500ms/div 2μs/div ______________ ______________ RESET, RESET Assertion RESET, RESET De-assertion (f) (f) RESET RESET 2V/div 2V/div 2V/div _____________ RESET _____________ RESET 2V/div 200ns/div 200ns/div VCC VCC 10kΩ RESET RESET 10kΩ RESET 330pF GND 330pF 330pF GND (e) 10kΩ (f) ________________________________________________________________________ http://www.union-ic.com Rev.05 Mar.2015 9/17 UM706xS/UM708xS/UM813xS Detailed Description Power-Fail Reset The reset output provides a reset signal to the microprocessor whenever the VCC input is below the threshold. An internal timer holds the reset output active for 200ms after the voltage on V CC rises above the threshold. This is intended as a power-on reset signal for the microprocessor. It allows time for both the power supply and the microprocessor to stabilize after power-up. If a power supply brownout or interruption occurs, the reset line is similarly activated and remains active for 200ms after the supply recovers. If another interruption occurs during an active reset period, the reset timeout period continues for an additional 200ms. The reset output is guaranteed to remain valid with VCC as low as 1V. This ensures that the microprocessor is held in a stable shutdown condition as the power supply starts up. ______________ The UM706xS provides an active low RESET signal while the UM813xS provides an active high RESET signal. The UM708xS has both an active high RESET output and an active low _____________ RESET output. Power-Fail Comparator The power-fail comparator can be used for various purposes because its output and non-inverting input are not internally connected. The inverting input is internally connected to a 1.25V reference. To build an early-warning circuit for power failure, connect the PFI pin to a voltage driver, choose the voltage divider ratio so that the voltage at PFI falls below 1.25V just before the regulator drops ________ out. Use PFO to interrupt the µP so it can prepare for an orderly power-down. Manual Reset _______ The Manual-Reset input (M R ) allows reset to be trigged by a pushbutton switch. The switch is _______ effectively debounced by the 140ms minimum reset pulse width. M R is TTL/CMOS logic _______ compatible, so it can be driven by an external logic line. If unused, M R input can be tied high or left floating. Watchdog Timer The UM706xS/UM813xS watchdog circuit monitors the μP’s activity. If the μP does not toggle __________ the watchdog input (WDI) within 1.6sec and WDI is not three-stated, WDO goes low. As long as _____________ RESET is asserted or the WDI input is three-stated, the watchdog timer will stay cleared and will not count. As soon as reset is released and WDI is driven high or low, the timer will start counting. Pulses as short as 50ns can be detected. __________ Typically, WDO will be connected to the non-maskable interrupt input (NMI) of a μP. When VCC __________ drops below the reset threshold, WDO will go low whether or not the watchdog timer has timed _____________ out yet. Normally this would trigger an NMI interrupt, but RESET goes low simultaneously, and thus overrides the NMI interrupt. __________ If WDI is left unconnected, WDO can be used as a low-line output. Since floating WDI disables __________ the internal timer, WDO goes low only when VCC falls below the reset threshold, thus functioning as a low-line output. _____________ The UM706xS has a watchdog timer and a RESET output. The UM708xS has both active-high and active-low reset outputs. The UM813xS has both an active-high reset output and a watchdog timer. ________________________________________________________________________ http://www.union-ic.com Rev.05 Mar.2015 10/17 UM706xS/UM708xS/UM813xS tWP WDI tWD tWD tWD +5V 0V +5V WDO 0V +5V RESET RESET EXTERNALLY TRIGGERED BY MR 0V tRS Figure 6. Watchdog and Reset Timing VCC VRT VRT tRS tRS +5V RESET 0V +5V MR 0V tMD tMR +5V WDO MR EXTERNALLY DRIVEN LOW 0V Figure 7. Reset, Manual Reset and Watchdog Timing ________________________________________________________________________ http://www.union-ic.com Rev.05 Mar.2015 11/17 UM706xS/UM708xS/UM813xS Applications Information ______________ Valid RESET below 1V VCC The UM706xS/UM708xS/UM813xS are guaranteed to provide a valid reset level with VCC as low as 1V. When VCC falls below 1V, the internal transistor does not have sufficient drive to hold it on _____________ _____________ so the voltage on RESET is no longer held at 0V. If a pull-down resistor is added to the RESET pin as shown in Figure 8, any stray charge or leakage current will be drained to ground, holding _____________ RESET low. Resistor value (R1) is not critical. It should be about 100kΩ, large enough not to _____________ _____________ load RESET and small enough to pull RESET to ground. Monitoring Additional Supply Levels It is possible to use the power-fail comparator to monitor a second supply as shown in Figure 9. The two sensing resistors, R1 and R2, are selected such that the voltage on PFI drops below 1.25V _________ ________ at the minimum acceptable input supply. The P F O output can be connected to the M R input so that a reset is generated when the supply drops out of tolerance. In this case, if either supply drops out of tolerance, a reset is generated. Monitoring a Negative Voltage The power-fail comparator can also monitor a negative supply rail (Figure 10). When the negative ________ rail is good (a negative voltage of large magnitude), PFO is low, and when the negative rail is ________ degraded (a negative voltage of lesser magnitude), PFO is high. By adding the resistors and ________ ________ transistor as shown, a high PFO triggers reset. As long as PFO remains high, _____________ theUM706xS/UM708xS/UM813xS will keep reset asserted (RESET=low, RESET=high). Note that this circuit’s accuracy depends on the PFI threshold tolerance, the VCC line, and the resistors. Microprocessor with Bidirectional Reset To prevent contention for microprocessors with a bidirectional reset line, a current limiting _____________ resistor is to be inserted between the RESET output pin and the microprocessor reset pin. This limits the current to a safe level if there are conflicting output reset levels. A suitable resistor value is 4.7kΩ. If the reset output is required for other uses, it should be buffered as shown in Figure 11. ________________________________________________________________________ http://www.union-ic.com Rev.05 Mar.2015 12/17 UM706xS/UM708xS/UM813xS VX +5V VCC VCC RESET To μP R1 RESET MR R2 R1 PFI GND Figure 8. Reset Valid to Ground Circuit GND PFO Figure 9. Monitoring an Additional Supply VX +5V 100kΩ VCC MR R1 100kΩ PFI PFO RESET GND R2 2N3904 BUFFERED RESET TO OTHER SYSTEM COMPONENTS To μP VCC VCC V- µP +5V MR RESET 4.7kΩ RESET 0V +5V PFO 0V V5-1.25 R1 = VTRIP 0V GND GND 1.25-VTRIP ,VTRIP＜0 R2 Figure 10. Monitoring a Negative Voltage Figure 11. Bidirectional Reset I/O ________________________________________________________________________ http://www.union-ic.com Rev.05 Mar.2015 13/17 UM706xS/UM708xS/UM813xS Package Information UM706xS SOP8 Outline Drawing c L D E E1 Symbol 1 2 θ e Top View A A2 End View A1 b Side View A A1 A2 b c D E E1 e L θ DIMENSIONS MILLIMETERS INCHES Min Max Min Max 1.350 1.750 0.053 0.069 0.100 0.250 0.004 0.010 1.350 1.550 0.053 0.061 0.33 0.51 0.013 0.020 0.170 0.250 0.006 0.010 4.700 5.100 0.185 0.200 3.800 4.000 0.150 0.157 5.800 6.200 0.228 0.244 1.270 (BSC) 0.050 (BSC) 0.400 1.270 0.016 0.050 0° 8° 0° 8° 4.95 1.30 Land Pattern 1.27 0.50 NOTES: 1. Compound dimension: 4.90×3.90; 2. Unit: mm; 3. General tolerance ±0.05mm unless otherwise specified; 4. The layout is just for reference. Tape and Reel Orientation UM706 XS XX ________________________________________________________________________ http://www.union-ic.com Rev.05 Mar.2015 14/17 UM706xS/UM708xS/UM813xS UM708xS SOP8 Outline Drawing c L D E E1 Symbol 1 2 θ e Top View A A2 End View A1 b Side View A A1 A2 b c D E E1 e L θ DIMENSIONS MILLIMETERS INCHES Min Max Min Max 1.350 1.750 0.053 0.069 0.100 0.250 0.004 0.010 1.350 1.550 0.053 0.061 0.33 0.51 0.013 0.020 0.170 0.250 0.006 0.010 4.700 5.100 0.185 0.200 3.800 4.000 0.150 0.157 5.800 6.200 0.228 0.244 1.270 (BSC) 0.050 (BSC) 0.400 1.270 0.016 0.050 0° 8° 0° 8° 4.95 1.30 Land Pattern 1.27 0.50 NOTES: 1. Compound dimension: 4.90×3.90; 2. Unit: mm; 3. General tolerance ±0.05mm unless otherwise specified; 4. The layout is just for reference. Tape and Reel Orientation UM708 XS XX ________________________________________________________________________ http://www.union-ic.com Rev.05 Mar.2015 15/17 UM706xS/UM708xS/UM813xS UM813xS SOP8 Outline Drawing c L D E E1 Symbol 1 2 θ e Top View A A2 End View A1 b Side View A A1 A2 b c D E E1 e L θ DIMENSIONS MILLIMETERS INCHES Min Max Min Max 1.350 1.750 0.053 0.069 0.100 0.250 0.004 0.010 1.350 1.550 0.053 0.061 0.33 0.51 0.013 0.020 0.170 0.250 0.006 0.010 4.700 5.100 0.185 0.200 3.800 4.000 0.150 0.157 5.800 6.200 0.228 0.244 1.270 (BSC) 0.050 (BSC) 0.400 1.270 0.016 0.050 0° 8° 0° 8° 4.95 1.30 Land Pattern 1.27 0.50 NOTES: 1. Compound dimension: 4.90×3.90; 2. Unit: mm; 3. General tolerance ±0.05mm unless otherwise specified; 4. The layout is just for reference. Tape and Reel Orientation UM813 XS XX ________________________________________________________________________ http://www.union-ic.com Rev.05 Mar.2015 16/17 UM706xS/UM708xS/UM813xS 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.05 Mar.2015 17/17