M62021L Datasheet, PDF (1/14 Pages) Mitsubishi Electric Semiconductor – SYSTEM RESET IC WITH SWITCH FOR MEMORY BACK-UP

M62021L/P/FP
System Reset IC with Switch for Memory Backup
REJ03D0784-0200
Rev.2.00
Jun 15, 2007
Description
The M62021 is a system IC that controls the memory backup function of microcomputer (internal RAM).
The IC outputs reset signals (RES/RES) to a microcomputer at power-down and power failure. It also shifts the power
supply to RAM from main to backup, outputs a signal (CS) that invokes standby mode, and alters RAM to backup
circuit mode.
The M62021 contains, in a single chip, power supply monitor and RAM backup functions needed for a microcomputer
system, so that the IC makes it possible to construct a system easily and with fewer components compared with a
conventional case that uses individual ICs and discrete components.
Features
• Built-in switch for selection between main power supply and backup power supply to RAM.
• Small difference between input and output voltage (I_OUT = 80 mA, V_IN = 5 V) 0.2 V Typ
• Detection voltage (power supply monitor voltage) 4.40 V ± 0.2 V
• Chip select signal output (CS)
• Two channels of reset outputs (RES/RES)
• Power on reset circuit built-in
• Delay time variable by an external capacitance connected to Ct pin
• Facilitates to form backup function with a few number of components
Application
• Power supply control systems for memory backup of microcomputer system and SRAM boards with built-in backup
function that require switching between external power supply and battery.
Block Diagram
V_IN 3
R₁
R₂
Com
–
+
1.24V
SW
Reset
circuit
RES 7
RES 5
Delay
circuit
6
GND
1 V_OUT
D₁
2 V_BAT
8 CS
4 Ct
REJ03D0784-0200 Rev.2.00 Jun 15, 2007
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