System Reset (with built-in watchdog timer) MM1135, MM1136 MITSUMI System Reset (with built-in watchdog timer) Monolithic IC MM1135, MM1136 Outline These ICs were developed to drive low voltage batteries, and have a watchdog timer with built-in microcomputer reset voltage detection circuit and low battery detection circuit. A single reference voltage is used for low battery voltage detection and microcomputer reset voltage . detection, so detection voltage difference is uniform ( =. 0.2V). Further, there is a built-in watchdog timer for operation diagnosis, which prevents the system from running wild by generating an intermittent reset pulse during system mis-operation. Features 1. Accurate voltage drop detection voltage 1. Low battery detection 3.4V±3% 2. Power supply voltage detection 3.2V±3% 3. Detection voltage error 0.2V±20mV 1-2 4. Hysteresis Both 50mV typ. 2. Watchdog function stop pin (can be made to function only as reset IC during VCC rise) 3. Low current consumption 150µA typ. Package SOP-8C (MM1135XF, MM1136XF) Applications 1. 3V cordless telephones 2. Various types of small, handy equipment Series Table Model MM1135 MM1136 VSLB VSLR 3.4V 3.2V TPR TWD TWR 100mS 10mS 2mS 100mS 100mS 2mS *C =0.02µF T TPR : Reset hold time during VCC rise TWD : Timer monitoring time TWR : Reset time VSLB : Battery check detection voltage VSLR : Reset detection voltage System Reset (with built-in watchdog timer) MM1135, MM1136 MITSUMI Pin Assignment TC 1 ---------------------------------------------------------------------------------------- 8 7 1 2 6 3 5 4 2 BC (RESET) 3 CK 4 GND 5 VCC 6 RCT VS 7 ---------------------------------------------------------------------------------------- SOP-8C RESET 8 Pin Description Pin No. 1 Pin name TC ---------------------------------------------------------------------------------------- 2 BC (RESET) 3 CK 4 GND 5 VCC 6 RCT 7 VS ---------------------------------------------------------------------------------------- 8 Block Diagram RESET Function TWD, TWR, TPR time setting pins. Battery check output pin (RESET low level output) for 3.4V Clock input pin GND pin Power supply voltage input pin Watchdog timer stop pin Operation OPEN, Stop connect to GND Detection voltage fine adjustment pin Reset output pin (low output) System Reset (with built-in watchdog timer) MM1135, MM1136 MITSUMI Absolute Maximum Ratings Item Symbol Rating Units Power supply voltage VCC max. -0.3~+7 V Voltage applied to input pin VIN -0.3~VCC+0.3 ( <= +7) V Voltage applied to output pin VOUT -0.3~VCC+0.3 ( <= +7) V Allowable loss Pd 450 mW Storage temperature TSTG -40~+125 °C Recommended Operating Conditions Item Symbol Rating Units Power supply voltage VCC +2.5~+6.5 V RESET sync current IOLR 0~1.5 mA BC sync current IOLC 0~1.5 mA Clock input high level voltage VCKH 1.4< V Clock input low level voltage VCKL <0.4 V Clock monitoring time setting TWD 1~1000 mS Clock rise and fall times tRCK, tFCK <100 µS Power supply voltage rise times tRVCC 100< µS Power supply voltage fall times tFVCC 50< µS TC pin capacitance CT 0.002~2 µF Operating temperature TOP -25~+75 °C -------------------------------------------------- System Reset (with built-in watchdog timer) MM1135, MM1136 MITSUMI Electrical Characteristics (Except where noted otherwise, Ta=25°C, Vcc=3.8V) Item Symbol Measurement conditions Consumption current ICC No load RESET detection voltage VSLR Detection voltage VSR temperature coefficient R T Hysteresis voltage R VHYSR BC detection voltage VSLB Detection voltage VSB temperature coefficient B T Hysteresis voltage B Detection voltage difference CK input threshold VHYSB VSL VCC : High Low RCT : GND, VTC=OPEN Min. Typ. Max. Units 3.10 200 280 µA 3.20 3.30 V ±0.01 ±0.05 %/°C VCC : Low High RCT : GND, VTC=OPEN VCC : High Low, RLB=10kΩ 25 50 100 mV 3.30 3.40 3.50 V ±0.01 ±0.05 %/°C VCC : Low High, RLB=10kΩ VSL=VSLB-VSLR VTH 25 50 100 mV 0.18 0.20 0.22 V 0.8 1.2 2 V 0 1 -15 -6 -2 IIH VCK=3.8V IIL VCK=0.0V Output voltage RH VOHR IRESET=-5µA --------------------------------------------------- 3.0 3.4 V Output voltage BH VOHB RLB=10kΩ 3.2 3.6 V CK input current Output voltage RL VOLR Output voltage BL VOLB --------------------------------------------------- µA IRESET=1mA, VCC=3.0V 0.3 0.5 V IBC=5mA, VCC=3.0V 0.3 0.5 V --------------------------------------------------- Output sync current R IOLR VRESET=0.5V, VCC=3.0V 1 2 mA Output sync current B IOLB VBC=0.5V, VCC=3.0V 5 10 mA 8 15 µA Output source current R CT charge current Minimum operating power supply ----------------------------------------------- voltage to ensure RESET IOHR --------------------------------------------------- VRESET=3.4V ICT1 VTC=1.0V during watchdog timer operation -0.48 -0.24 -0.16 µA ICT2 VTC=1.0V during power ON reset operation -0.48 -0.24 -0.16 µA --------------------------------------------------- VCC VRESET=0.4V --------------------------------------------------- IRESET=0.1mA 0.8 1.0 V System Reset (with built-in watchdog timer) MM1135, MM1136 MITSUMI 3.8V VCC input pulse width TPI VCC CK input pulse width TCKW CK CK input cycle TCK CK Watchdog timer monitoring time 1 * Watchdog timer reset time 2 2.8V TPI TCKW or TCK 8 µS 3 µS 20 µS TWD CT=0.02µF 50 100 150 mS TWR CT=0.02µF 1 2 3 mS TPR CT=0.02µF 50 100 150 mS * Reset hold time for power supply rise 3 * ------------------------------------------ RESET delay time tPDR VCC : High Low, RLR=10kΩ, CLR=15pF 10 µS BC delay time tPDB VCC : High Low, RLB=4.7kΩ, CLB=15pF 10 µS ------------------------------------------ tRR RLR=10kΩ, CLR=15pF 10 µS RESET fall time tFR RLR=10kΩ, CLR=15pF 2 µS BC rise time tRB RLB=4.7kΩ, CLB=15pF 10 µS BC fall time tFB RLB=4.7kΩ, CLB=15pF 2 µS RESET rise time ------------------------------------------ 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 (VSHR) during power ON reset until reset release (RESET output high). 4 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. TPR (mS) .=. 5000 CT (µF) TWD (mS) .=. 5000 CT (µF) TWR (mS) .=. 100 CT (µF) Example : When CT=0.02µF TPR .=. 100mS TWD .=. 100mS TWR .=. 2mS 5 TWD can be varied by placing a resistor (1MEGΩ or more) between the RCT pin and VCC. 6 The voltage range when measuring output rise and fall time is 10~90%. 7 VCC rise time should be 100µS or more, and fall time should be 50µS or more. * * * * * * * ----------------------------------------------------- System Reset (with built-in watchdog timer) MM1135, MM1136 MITSUMI Measuring Circuit Timing Chart VSHB VCC VSLB VSMR VSLR 0.8V CK TCKW TCK CT RESET TPR TWR TWD BC RCT Undefined Basic Circuit Diagram