memory products - Al Kossow's Bitsavers

ST27256P256K (32K x 8) NMOS ONE TIME PROGRAMMABLE ROM• FAST ACCESS TIME: 170ns• 0 to + 70°C STANDARD TEMP. RANGE• SINGLE + 5V POWER SUPPLY• ±10% Vcc TOLERANCE AVAILABLE• LOW STANDBY CURRENT (40mA MAX)• TTL COMPATIBLE DURING READ ANDPROGRAM• FAST PROGRAMMING ALGORITHM• ELECTRONIC SIGNATURE"f~':'-:-":::~.'.::.:':':......'...'.'.. '..:: ..'.:'.'.::........•.....•.......... ::...':..'.. ,..:, .. :::..•.•. !: .. ,.•.::...:.•...•.•. :_.::.:~.:.:: .•. .•. :.•.•..",.:..·..•.•.)i\;;!!;~l!r;·y·2B1BDIP-28(Plastic Package)(Ordering Information at the end of the datasheet)DESCRIPTIONThe ST27256P is a 262, 144-bit one time programmableread only memory (OTP ROM). It is organizedas 32.768 words by 8 bits and manufacturedusing SGS-THOMSON' NMOS-E3 process. TheST27256P with its single + 5V power supply andwith an access time of 200ns, is ideal for use withhigh performance + 5V microprocessor such as Z8,Z80 and Z8000. The ST27256P has an importantfeature which is to separate the output control, Q!wtutEnable (OE) from the Chip Enable control (CE).The OE control eliminates bus contention in mUltiplebus microprocessor systems. The ST27256Palso features a standby mode which reduces thepower disSipation without increasing access time.The active current is 100mA while the maximumstandby current is only 40 mA, a 60% saving. Thestandby mode is achieved by applying a TTL-highsignal to the CE input. The ST27256P enables implementationof new, advanced systems with firmwareintensive architectures. The combination ofthe ST27256P's high density, and new advancedmicroprocessors having megabit addressing capabilityprovides designers with opportunities to engineeruser-friendly, high reliability, high-performancesystems. The ST27256P large storage capabilityenables it to function as a high density softwarecarrier. Entire operating systems, diagnostics,high-level language programs and specialized applicationsoftware can reside in a ST27256P directlyon a system's memory bus. This permits immediatemicroprocessor access and execution of softwareand eliminates the need for time consuming diskaccesses and downloads. The ST27256P has an"Electronic Signature" that allows programmersto automatically identify device type and pinout.PIN NAMESAO-A14CEOEPIN CONNECTIONS----~Vpp 1 2Bb VceA12 27 A14A7 26 A13A6 25 A8AS 24 A"A4 I 6 23 A11A3 22 OEA2 2' Al0Al 20 TIAO '0 19 0100 11 IS 0601"17 0502 13 '6 04GND '5 03"s - 7516ADDRESS INPUTCHIP ENABLE INPUTOUTPUT ENABLE INPUT00-07 DATA INPUT/OUTPUTJune 19881/10165