System Reset (with built-in watchdog timer) MM1035 MITSUMI System Reset (with built-in watchdog timer) Monolithic IC MM1035 Outline This IC functions in a variety of CPU systems and other logic systems to generate a reset signal and reset the system accurately during momentary interruption or lowering of power supply voltage. It also has a built-in watchdog timer for operation diagnosis. This prevents the system from running wild by generating an intermittent reset pulse during system mis-operation. Features 1. 2. 3. 4. 5. 6. Built-in watchdog timer Low minimum operating voltage VCC=0.8V typ. Both positive and negative logic reset output can be extracted Accurate detection of drop in power supply voltage Detection voltage has hysteresis Few external parts 1 capacitor Package DIP-8A (MM1035XD) SOP-8A (MM1035XF) Applications Microcomputers Absolute Maximum Ratings (Ta=25°C) Item Symbol Rating Units Storage temperature TSTG -40~+125 °C Operating temperature TOPR -20~+70 °C Power supply voltage VCC max. -0.3~+10 V Voltage applied to VS & CK pins VVS & VCK -0.3~+10 V Voltage applied to RESET, RESET pin VOH -0.3~+10 V Allowable loss Pd 400 mW System Reset (with built-in watchdog timer) MM1035 MITSUMI Electrical Characteristics 1 (DC) Item Symbol Consumption current ICC (Except where noted otherwise, Ta=25°C, VCC=5V, measurement circuit 1) Measurement Measurement conditions Min. Typ. Max. Units 1 During watchdog timer operation 0.7 1.0 mA VSL 1 VS=OPEN, VCC 4.05 4.20 4.35 VSH 1 VS=OPEN, VCC 4.15 4.30 4.45 VS/ T 1 Hysteresis voltage VHYS 1 CK input threshold VTH 1 IIH 1 VCK=5V IIL 1 VCK=0V VOH1 1 VOH2 VOL1 Detection voltage Detection voltage temperature coefficient CK input current Output voltage (High) Output voltage (Low) Output sink current circuit ------------------------------------------------ supply voltage to ensure RESET Minimum operating power ------------------------------------------------ supply voltage to ensure RESET %/°C 50 100 150 mV 0.8 1.2 2 V 0 1 -20 -10 -3 I RESET =-5µA, VS=OPEN 4.5 4.8 1 IRESET=-5µA, VS=0V 4.5 4.8 1 I RESET =3mA, VS=0V VSH-VSL, VCC ----------------------------------------- ----------------------------------------- ----------------------------------------- 0.2 0.4 1 I RESET =10mA, VS=0V 0.3 0.5 VOL3 1 IRESET=0.5mA, VS=OPEN 0.2 0.4 VOL4 1 IRESET=1mA, VS=OPEN 0.3 0.5 ------------------------------------------- µA V VOL2 V IOL1 1 V RESET =1.0V, VS=0V 10 16 IOL2 1 VRESET=1.0V, VS=OPEN 1 2 ICT1 1 -8 -12 -24 µA ICT2 1 -0.8 -1.2 -2.4 µA 0.8 1.0 V 0.8 1.0 V CT charge current Minimum operating power ±0.01 V VTC = 1.0V during watchdog timer operation VTV = 1.0V during power on reset operation mA -------------------------------------------- VCCL1 1 V RESET =0.4V ------------------------------------------------ I RESET =0.2mA VCCL2 1 IRESET=VCC-0.1V RL2 (between Pin 2 and GND) =1MΩ System Reset (with built-in watchdog timer) MM1035 MITSUMI Electrical Characteristics 2 (AC) (Except where noted otherwise, Ta=25°C, VCC=5V, measurement circuit 2) Measurement Item Symbol VCC input pulse width TPI 2 VCC CK input pulse width TCKW 2 CK CK input cycle TCK 2 TWD 2 CT=0.1µF 5 10 15 mS TWR 2 CT=0.1µF 1 2 3 mS TPR 2 50 100 150 mS 2 10 Watchdog timer monitoring time 1 circuit Measurement conditions 5V 4V or Min. Typ. Max. Units 8 µS 3 µS 20 µS * Reset time for watchdog timer 2 * Reset hold time for power supply rise 3 * Output delay time from VCC 4 * CT=0.1µF, VCC --------------------------------------- TPD1 TPD2 2 2 RESET pin RL1=2.2kΩ, CL1=100pF RESET pin RL2=10kΩ, CL2=20pF µS 3 10 1.0 1.5 µS 1.0 1.5 µS ---------------------------------------- Output rise time *5 tR1 2 tR2 2 RESET pin RL1=2.2kΩ, CL1=100pF RESET pin RL2=10kΩ, CL2=20pF Notes : 1: Monitoring time is the time from the last pulse (negative edge) of the timer clear clock pulse, until reset pulse output. In other words, reset output is output if a clock pulse is not input during this time. 2: Reset time means reset pulse width. However, this does not apply to power on reset. 3: Reset hold time is the time from when VCC exceeds detection voltage (VSH) during power on reset, until --------------------------------------RESET output goes high (reset release). 4: Output delay time is the time from when power supply voltage drops below detection voltage (VSL), until --------------------------------------RESET output goes low (reset status). 5: Voltage range when measuring output rise and fall is 10~90%. 6: Watchdog timer monitoring time (TWD), watchdog timer reset time (TWR) and reset hold time (TPR) during power supply rise can be changed by varying CT capacitance. The times are expressed by the following formulae. The recommended range for CT is 0.001~10µF. * * * * * * . TPR (mS) =. 1000 CT (µF) TWD (mS) .=. 100 CT (µF) . TWR (mS) =. 20 CT (µF) Example : When CT=0.1µF TPR .=. 100mS . TWD =. 10mS . TWR =. 2mS System Reset (with built-in watchdog timer) MM1035 MITSUMI Block Diagram Note 1: CP = 0.1µF approx. ~1000pF. Note 2: C Note 3: The watchdog timer can be stopped by connecting the RCT pin to GND. (Then it functions as a voltage detection circuit.) Timing Chart VCC VSH VSL CK TCK CT RESET TPR TWD TWR RESET Pin Assignment 8 1 7 2 6 3 5 4 1 TC 2 RESET 3 CK 4 GND 5 VCC 6 RCT 7 VS ----------------------------------------- 8 RESET System Reset (with built-in watchdog timer) MM1035 MITSUMI Pin Description Pin No. Pin Name 1 TC 2 RESET 3 CK 4 GND 5 VCC 6 RCT 7 VS --------------------------------------------------------------- 8 RESET Measuring Circuit Measuring Circuit 1 (DC) Measuring Circuit 2 (AC) Function TWD, TWR, TPR variable pins. (TWD, TWR and TPR times are determined by the external capacitor.) Reset output pin (High output) Clock input pin (inputs clock from logic system) Reset output pin (High output) 4.2V detection voltage Watchdog timer stop pin Operation modes: Operation OPEN, Stop connect to GND Detection voltage variable pin Variation modes : Lower pull up resistance, Raise Reset output pin (Low output) pull down System Reset (with built-in watchdog timer) MM1035 MITSUMI Measuring Circuit 1 Item SW Table 6-1-2. SW&Power Supply Table 1 Symbol SW1 SW2 SW3 SW4 SW5 SW6 SW7 VCC Consumption current Output voltage (Low) I RESET ---------------------------------------- IRESET VM, IM Notes ICC OFF OFF OFF ON B B ON 5V 0V - - ICC VSL OFF OFF ON ON B B ON 5V 0V 3V 3V - - VO1, CRT1 OFF OFF ON ON B B ON 4V 5V 3V 3V - - VO1, CRT1 VTH OFF OFF OFF ON B B ON 5V 0V 3V 1V - - ICK IIH OFF OFF OFF ON B B ON 5V 5V 0V - - ICK IIL CK input current Output voltage (High) VCT VSH Detection voltage CK input threshold 5V VCK OFF OFF OFF ON B B ON 5V 0V 0V - - ICK VOH1 ON OFF ON B B ON 5V 5V 3V -5µA - VO1 VOH2 OFF ON ON ON C B ON 5V 5V 3V - -5µA VO2 VOL1 ON ON ON ON B B ON 5V 5V 3V 3mA - VO1 VOL2 ON ON ON ON B B ON 5V 5V 3V 10mA - VO1 VOL3 OFF OFF ON ON C B ON 5V 5V 3V - 0.5mA VO2 VOL4 OFF OFF ON ON C B ON 5V 5V 3V - 1mA VO2 ON IOL1 OFF ON ON ON B C ON 5V 5V 3V - - I O1 VOO=1V IOL2 OFF OFF ON ON B A ON 5V 5V 3V - - I O2 VOO=1V CT charge current 1 ITC1 OFF OFF OFF ON B B OFF 5V - 1V - - ITC CT charge current 2 ITC2 OFF OFF ON ON B B OFF 5V - 1V - - ITC VCCL1 ON OFF ON ON B B ON 0V 2V 0V 0V - VO1, VCC VCCL2 OFF ON ON A B ON 0V 2V 0V 0V - - VO2, VCC VCK CRT Notes - CRT1,2,3 T1=8µS - CRT1,2,3 T2=3µS - CRT1,2,3 T3=20µS Output sink current Minimum operating power supply voltage to ensure reset Minimum operating power supply voltage to ensure reset Measuring Circuit 2 Item SW Table 6-2-2. SW&Power Supply Table 2 Symbol SW1 SW2 VCCA 5V T1 VCC - VCKA 1.4V T2 T3 C B CK input pulse width TCKW A B 5V TCK A B 5V TWD A A 5V 5V CRT1,2,3 TWR A A 5V 5V CRT1,2,3 A 5V 5V CRT1,2,3 - 0V CRT1,3 - 0V CRT2,3 VCC input pulse width CK input cycle Watchdog timer monitoring time Reset time for watchdog timer Reset hold time for power supply rise Output delay time from VCC Output rise time Output fall time TPI ON TPR B A 4V 5V 0V 1.4V 0V 1.4V 0V T2 or T2 T2 T3 TPD1 C A TPD2 C A TR1 A A 5V 5V CRT1 TR2 A A 5V 5V CRT2 TP1 A A 5V 5V CRT1 TP2 A A 5V 5V CRT2 0V 5V 0V System Reset (with built-in watchdog timer) MM1035 MITSUMI Detection Voltage Variation 1 (lowering detection voltage) Detection voltage can be changed by connecting resistor R1 externally to MM1035 Vs pin. Determine R1 according to graph 1 when changing Vs. Graph 1. Detection voltage change using MM1035 external resistor Detection voltage (Vs) (V) VSH value 4.0 VSL value 3.5 3.0 100 200 300 400 500 600 Vs pin external resistance (R1) (kΩ) Detection Voltage Variation 2 (raising detection voltage) Detection voltage can be changed by connecting resistor R2 externally to MM1035 Vs pin. Determine R2 according to graph 2 when changing Vs. Graph 2. Detection voltage change using MM1035 external resistor Detection voltage (Vs) (V) 5.0 VSH value 4.5 VSL value 100 200 300 400 500 600 Vs pin external resistance (R1) (kΩ) System Reset (with built-in watchdog timer) MM1035 MITSUMI Characteristics 1.4 1.2 1.0 Output voltage-Power supply voltage (RESET pin) PULL UP resistance 10kΩ 7.0 0.8 0.6 0.4 0.2 Clock pulse input time 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 Power supply current Icc (mA) Power supply current Icc (mA) Power supply current-Power supply voltage 6.0 5.0 Ta=20°C.25°C.75°C 4.0 3.0 2.0 1.0 Power supply voltage VCC (V) 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 Power supply voltage VCC (V) ------------------------------------------------------------------ Output voltage-Power supply voltage (RESET pin) --------------------------------------------------------------------------- Detection voltage (VSL, VSH) temperature (RESET, RESET pins) 6.0 4.40 Detection voltage (V) 4.50 5.0 4.0 3.0 2.0 1.0 Ta=-25°C Ta=25°C Output saturation voltage VOL (mV) 4.20 VSL 4.10 4.00 -40 -20 0 Power supply voltage VCC (V) Ambient temperature Ta (°C) ---------------------------------------------------------------- 500 400 Ta=25°C Ta=75°C 200 100 4.30 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 Output saturation voltage-Output sink current (RESET pin) 300 VSH 3.00 Ta=75°C Ta=-25°C 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 Output sink current IOL (mA) 20 40 60 80 100 ------------------------------------------------------------------------------ Output saturation voltage-Output sink current (RESET pin) Output saturation voltage VOL (mV) Output voltage VRESET (V) PULL UP resistance 2.2kΩ 7.0 Ta=25°C 500 400 Ta=75°C 300 200 Ta=-25°C 100 2 4 6 8 10 12 14 16 18 Output sink current IOL (mA) System Reset (with built-in watchdog timer) MM1035 MITSUMI 5.0 High level output voltage - High level output current (RESET pin) ------------------------------------------------ 5.0 High level output voltage VOM (V) High level output voltage VOM (V) High level output voltage-High level output current (RESET pin) 4.8 4.6 4.4 4.2 4.0 3.8 4.8 4.6 4.4 4.2 4.0 3.8 -2 -4 -6 -8 -10-12-14 -16-18 -2 -4 -6 -8 -10-12-14-16-18 High level output current IOM (µA) Reset hold time temperature during power supply rise High level output current IOM (µA) Watchdog timer monitoring time temperature VCC=5V (Cr=0.1µF) Watchdog timer monitoring time temperature TWD (mS) Reset hold time temperature during power supply rise TPR (mS) VCC=5V (Cr=0.1µF) 160 140 120 100 80 60 40 -40 -20 0 16 14 12 10 8 6 4 -40 -20 0 20 40 60 80 100 Ambient temperature Ta (°C) Reset time temperature (for watchdog timer) 20 40 60 80 100 Ambient temperature Ta (°C) CT value for reset hold time during power supply rise VCC=5V (Cr=0.1µF) 3.0 105 Hold time TWD (mS) Reset time TWR (mS) 3.5 2.5 2.0 1.5 1.0 0.5 104 103 102 101 100 -40 -20 0 20 40 60 80 100 Ambient temperature Ta (°C) 10-3 10-2 10-1 100 101 CT capacitance (µF) System Reset (with built-in watchdog timer) MM1035 MITSUMI 103 Reset time TWR (mS) CT value for watchdog timer monitoring time Timer monitoring time TWD (mS) CT value for reset time (for watchdog timer) 102 101 100 10-1 10-2 104 103 102 101 100 10-1 10-3 10-2 10-1 100 101 10-3 10-2 10-1 100 101 CT capacitance (µF) CT capacitance (µF)