IC for System Reset (battery backup) Monolithic IC MM1134

Transcription

1 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 3.5, 4.2 typ.). Then, when supply voltage is getting lower, the main power supply is switched to a battery (switching voltage 3.3 typ.) to enter backup mode with the battery. Meanwhile, when the power supply rises, first it switches to the main power supply (switching voltage 3.3 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) 0.3µA typ. 2. Drop voltage inside IC (input/output voltage difference) IO=100µA 0.3 typ. 3. Reverse current (reverse leak current) 0.1µA max. 2. Normal operation 1. Drop voltage inside IC (input/output voltage difference) IO=50µA 0.2 typ. 2. Output voltage CC=5 IO=50mA 4.8 typ. 3. Battery-CC switching voltage 3.3 typ Detection voltage (CS, CS, reset output) A : 3.5 typ. B : 4.2 typ.

2 Package SOP-8C (MM1134 F) The box represents a rank of detection voltage. * Applications 1. Memory cards (SRAM cards) 2. PCs, word processors 3. Fax machines, photocopiers, other OA equipment 4. Sequence controllers, other FA equipment 5. SRAM-mounted devices such as video game devices Pin Assignment SOP-8C (TOP IEW) Block Diagram Pin no. Pin name 1 GND 2 RESET 3 CS 4 BATT 5 CS 6 OUT 7 Y 8 CC

3 Equivalent Circuit Diagram Absolute Maximum Ratings (Ta=25 C) Item Symbol Rating Units Storage temperature TSTG -40~+125 C Operating temperature TOPR -20~+75 C Power supply voltage CC max. -0.3~7 Operating voltage CCOP -0.3~7 Allowable loss Pd 300 mw Output current IO1 80 ma Output current IO2 200 µa Note : IO1 expresses CC output current value, and IO2 expresses BATT output current value.

4 Electrical Characteristics Typical model: MM1134B(Except where noted otherwise, Ta=25 C, CC=RS=5, RRS=10kΩ) Item Symbol Measuring circuit Measurement conditions Min. Typ. Max. Units Consumption current ICC 1 CC=5, BATT=3, IO1=0mA ma I/O voltage difference 1 SAT1 1 CC=5, BATT=3, IO1=1mA Output voltage 1 O1 1 CC=5, BATT=3, IO1=1mA Output voltage 2 O2 1 CC=5, BATT=3, IO1=15mA Output voltage 3 O3 1 CC=5, BATT=3, IO1=50mA Detection voltage S 1 CC=H L Hysteresis voltage S 1 CC=L H m Reset output voltage L RSL 1 CC= Reset leakage current H IRSH 1 CC=5, RS=7.0 ±0.01 ±0.1 µa Reset operation limit voltage OPL 1 RSL 0.4, CC=H L CS output voltage L CSL 1 CC=3.7, BATT=3, ICS=1µA 0.1 CS output voltage H CSH 1 CC=5, BATT=3, ICS=-1µA 4.90 CS output voltage L CSL 1 CC=5, BATT=3, ICS=1µA, Y=0 0.2 CS output voltage H CSH 1 CC=3.7, BATT=3, ICS=-1µA, Y=0 O-0.1 CC=5, BATT=3, ICS=-1µA, Y=5 Detection voltage temperature characteristic S/ T 1 ±0.05 %/ C Power supply switching voltage B 1 CC=H L Hysteresis voltage B 1 CC=L H m Switching voltage temperature characteristic B/ T 1 ±0.05 %/ C Loss current IBL 1 CC=0, BATT=3, IO2=0µA µa I/O voltage difference 2 sat2 1 CC=0, BATT=3, IO2=1µA Output voltage 4 O4 1 CC=0, BATT=3, IO2=1µA Output voltage 5 O5 1 CC=0, BATT=3, IO2=100µA Reverse current IORE 1 CC=5, BATT=0 0.1 µa Y pin Lo level current IYLO 1 CC=5, BATT=3, Y= µa Y pin tplh 2 Y=L H, CL=15pF 8 20 ns * Pin transmission delay time tphl 2 Y=H L, CL=15pF 8 20 ns * Reference voltage (typical) REF 1.25 Note : When input pulse rise and fall time is less than 6Nsec.

5 Measuring circuit 1 RS ICC A 1 8 A R RS 10k C1 0.1µF CC ICS BATT RS CS I A BATT MM C2 0.1µF CS A ILO O I CS IO

6 Measuring circuit 2 RRS 10k 1 8 C1 0.1µF CC BATT INPUT(Y) OUTPUT(CS) 2 7 MM tplh CL 15pF 50% C2 0.1µF Y Oscilloscope tphl 0.5CC CC GND CSH GND

7 Timing Chart CC E S S B OPL Y * Y 0 RESET RSL 0 CS CS OUT Characteristics OUT () IBAT (na) CSL CSL OUT-IOUT (CC=5.0) () /div O4,O5 CSL CSL O1,O2,O /div CC-IBAT /div * Use Y pin input voltage at less than 5 when CC < = s. IOUT (ma) OUT () ICC (ma) OUT-IOUT (BAT=3.0) /div CC-ICC /div IOUT (ma).5000/div /div CC () /div CC () 10.00

8 Current consumption-temperature characteristics Output voltage 1, 2-Temperature characteristics Current consumption (ma) Output voltage 3, 4-Temperature Output voltage 3, 4 () IOL=100µA IOL=1µA Reverse current-temperature Reverse current 1µA 100nA 10nA Output voltage 1, 2 () Loss current µA 100nA 10nA IOL=50mA IOL=10mA Loss current-temperature