DS1218+

The DS1218+ from Maxim Integrated Products is a non-volatile controller in 8 pin DIP package. It is a CMOS circuit which solves the application problems of converting CMOS RAM into non-volatile memory. Incoming power is monitored for an out of tolerance condition. When such a condition is detected, the chip enable output is inhibited to accomplish write protection and the battery is switched on to supply RAM with uninterrupted power. Special circuitry uses a low-leakage CMOS process which affords precise voltage detection at extremely low battery consumption. The 8-pin package keeps PC board real estate requirements to a minimum. By combining the DS1218 non-volatile controller chip with a full CMOS memory and lithium batteries, 10 years of non-volatile RAM operation can be achieved.

• Supply voltage range is 4.5V to 5.5V
• Operating temperature range from 0°C to 70°C
• Unconditionally write protects RAM when VCC is out of tolerance
• Automatically switches to battery when power fail occurs
• Consumes less than 100nA of battery current
• 2V to 5.5V logic 1 and -0.3V to 0.8V logic 0 voltage
• Battery supply voltage range from 2.5V to 3.5V
• 2mA active current, 80mA RAM current (VCCO >= VCCI -0.2V)
• 5pF input capacitance, 7pF output capacitance, 1.5µs active-low CE pulse width
• Maximum 2ms recovery at power-up, 500µs VCC slew rate, 4ns active-low CE propagation delay