NMC6551

The NMC6551 is a static CMOS random access read/write memory organized as 256 words of 4 bits each.This device is fabricated with national semiconductor's silicon-gate CMOS technology and is fully compatible with the TTL environment.

Features of the NMC6551 are:(1)industry standard pinout;(2);low data retention voltage is 2V;(3)low speed/power product;(4)TTL compatible is all inputs and outputs;(5)TRI-STATE outputs for bus operation;(6)high output drive;(7)high noise immunity;(8)military temperature range available;(9)on-chip address registers;(10)22 pin is high desity packaging;(11)output data latches;(12)select latch for microprocessor interface.

The absolute maximum ratings of the NMC6551 can be summarized as:(1):the symbol is TS,the parameter is storage temperature range,the value is -65 to +150,the unit is ;(2):the symbol is VI/O,the parameter is voltages at any pin,the value is -0.3 to VCC+0.3,the unit is V;(3):the symbol is TL,the parameter is lead temperature (soldering,10 sec),the value is +300,the unit is ;(4):the symbol is PD,the parameter is package dissipation,the value is 500,the unit is mW;(5):the symbol is VCC,the parameter is supply voltage VCC,the value is 7,the unit is V.