IC for System Reset (battery backup) MM1134 MITSUMI IC for System Reset (battery backup) Monolithic IC MM1134 Outline ------------------------------------------- This IC protects SRAM data by setting SRAM in backup mode (setting the CE pin of SRAM low and CE pin high with CS signal) when supply voltage falls below a predetermined voltage (detection voltage 3.5V, 4.2V typ.). Then, when supply voltage is getting lower, the main power supply is switched to a battery (switching voltage 3.3V typ.) to enter backup mode with the battery. Meanwhile, when the power supply rises, first it switches to the main power supply (switching voltage 3.3V typ.) from the battey backup mode, then switches SRAM from backup mode to normal mode (by setting the CE pin of SRAM high and CE pin low). Data damage can be reliably prevented by this signal processing. ------------------------------------------- Features 1. Power supply switching circuit (switching between the main power supply and a battery) 2. CS control for SRAM Normal mode: Enables access to SRAM Backup mode: Disables access to SRAM, low current consumption mode 3. With CS signal gate circuit Characteristics 1. Battery back-up 1. Low IC current consumption (loss current) 2. Drop voltage inside IC (input/output voltage difference) 3. Reverse current (reverse leak current) 2. Normal operation 1. Drop voltage inside IC (input/output voltage difference) 2. Output voltage VCC=5V 3. Battery-VCC switching voltage 4. Detection voltage (CS, CS, reset output) ----------------------------- IO=100µA IO=50µA IO=50mA A : 3.5V typ. B : 4.2V typ. 0.3µA typ. 0.3V typ. 0.1µA max. 0.2V typ. 4.8V typ. 3.3V typ. IC for System Reset (battery backup) MM1134 MITSUMI Package SOP-8C (MM1134 F) The box represents a rank of detection voltage. * Applications 1. 2. 3. 4. 5. Memory cards (SRAM cards) PCs, word processors Fax machines, photocopiers, other OA equipment Sequence controllers, other FA equipment SRAM-mounted devices such as video game devices Pin Assignment 8 7 6 5 1 2 3 4 SOP-8C (TOP VIEW) Block Diagram Pin no. 1 2 3 4 5 6 7 8 Pin name GND RESET CS VBATT CS VOUT Y VCC IC for System Reset (battery backup) MM1134 MITSUMI Equivalent Circuit Diagram Absolute Maximum Ratings Item Storage temperature Operating temperature Power supply voltage Operating voltage Allowable loss Output current Output current (Ta=25°C) Symbol TSTG TOPR VCC max. VCCOP Pd IO1 IO2 Rating -40~+125 -20~+75 -0.3~7 -0.3~7 300 80 200 Units °C °C V V mW mA µA Note : IO1 expresses VCC output current value, and IO2 expresses VBATT output current value. IC for System Reset (battery backup) MM1134 MITSUMI Electrical Characteristics Typical model: MM1134B(Except where noted otherwise, Ta=25°C, VCC=VRS=5V, RRS=10kΩ) Item Symbol Consumption current I/O voltage difference 1 Output voltage 1 Output voltage 2 Output voltage 3 Detection voltage Hysteresis voltage Reset output voltage L Reset leakage current H Reset operation limit voltage CS output voltage L CS output voltage H CS output voltage L ICC VSAT1 VO1 VO2 VO3 VS VS VRSL IRSH VOPL VCSL VCSH VCSL Measuring circuit 1 1 1 1 1 1 1 1 1 1 1 1 1 CS output voltage H VCSH 1 Detection voltage temperature characteristic VS/ T Power supply switching voltage VB Hysteresis voltage VB Switching voltage temperature characteristic VB/ T Loss current IBL I/O voltage difference 2 Vsat2 Output voltage 4 VO4 Output voltage 5 VO5 Reverse current IOREV Y pin Lo level current IYLO Y pin tpLH Pin transmission delay time tpHL Reference voltage (typical) VREF Note : 1 1 1 1 1 1 1 1 1 1 2 2 Measurement conditions Min. Typ. Max. Units VCC=5V, VBATT=3V, IO1=0mA VCC=5V, VBATT=3V, IO1=1mA VCC=5V, VBATT=3V, IO1=1mA VCC=5V, VBATT=3V, IO1=15mA VCC=5V, VBATT=3V, IO1=50mA VCC=H L VCC=L H VCC=3.7V VCC=5V, VRS=7.0V VRSL≤0.4V, VCC=H L VCC=3.7V, VBATT=3V, ICS=1µA VCC=5V, VBATT=3V, ICS=-1µA VCC=5V, VBATT=3V, ICS=1µA, VY=0V VCC=3.7V, VBATT=3V, ICS=-1µA, VY=0V VCC=5V, VBATT=3V, ICS=-1µA, VY=5V 4.95 4.75 4.70 4.00 50 When input pulse rise and fall time is less than 6Nsec. 2.2 0.05 4.40 200 0.4 ±0.1 1.2 0.1 4.90 0.2 VO-0.1 VCC=H L VCC=L H VCC=0V, VBATT=3V, IO2=0µA VCC=0V, VBATT=3V, IO2=1µA VCC=0V, VBATT=3V, IO2=1µA VCC=0V, VBATT=3V, IO2=100µA VCC=5V, VBATT=0V VCC=5V, VBATT=3V, VY=0V VY=L H, CL=15pF VY=H L, CL=15pF 1.4 0.03 4.97 4.90 4.80 4.20 100 0.2 ±0.01 0.8 3.15 50 2.7 2.6 * * mA V V V V V mV V µA V V V V V ±0.05 %/˚C 3.30 3.45 V 100 200 mV ±0.05 %/˚C 0.3 0.5 µA 0.2 0.3 V 2.8 V 2.7 V 0.1 µA 150 400 µA 8 20 ns 8 20 ns 1.25 V IC for System Reset (battery backup) MM1134 MITSUMI Measuring circuit 1 V RS ICC A A 8 1 C1 V CC 0.1µF R RS 10k 2 VRS V 7 A I VLO MM1134 3 I CS 6 V VCS C2 0.1µF A V BATT V I BATT 4 V VO 5 V V CS I CS IO IC for System Reset (battery backup) MM1134 MITSUMI Measuring circuit 2 1 8 C1 VCC 0.1µF R RS 10k 2 7 VY MM1134 6 3 C2 0.1µF 4 5 V BATT CL Oscilloscope 15pF VCC INPUT(VY) 50% GND VCSH OUTPUT(VCS) 0.5VCC GND tpLH tpHL IC for System Reset (battery backup) MM1134 MITSUMI Timing Chart VS VE VS VB VOPL VCC *V Y Y 0V VRSL RESET 0V CS VCSL 0V VCSL CS VCSL VCSL 0V VOUT VO1,O2,O3 0V VO4,O5 * Use Y pin input voltage at less than 5V when V CC < = Vs. Characteristics VOUT-IOUT (VCC=5.0V) VOUT-IOUT (VBAT=3.0V) 3.000 VOUT (V) VOUT (V) (V) 5.000 .0500/div 4.500 .0000 0.100/div 2.000 10.00/div 0 -100.0 IOUT (mA) 1.000 IOUT (mA) VCC-IBAT VCC-ICC 5.000 ICC (mA) 40.00 IBAT (nA) 0.100/div 5.000/div .5000/div 0 -10.00 0 1.000/div VCC (V) 10.00 .0000 .0000 1.000/div VCC (V) 10.00 IC for System Reset (battery backup) MM1134 MITSUMI Output voltage 1, 2-Temperature characteristics 0.3 2.0 Output voltage 1, 2 (V) Current consumption (mA) Current consumption-Temperature characteristics 1.0 0.0 -50 0 50 IOL=50mA 0.2 0.1 IOL=10mA -50 100 0 Ambient temperature (°C) Output voltage 3, 4 (V) Output voltage 3, 4-Temperature 0.5 0.4 IOL=100µA 0.3 0.2 IOL=1µA 0.1 0 -50 0 50 100 Ambient temperature (°C) Reverse current-Temperature Loss current-Temperature 1µA Loss current Reverse current 1µA 100nA 10nA -80 -50 0 50 100 Ambient temperature (°C) 50 Ambient temperature (°C) 100nA 10nA -80-50 0 50 100 Ambient temperature (°C) 100