DS1543

www.dalsemi.com FEATURES Integrated NV SRAM, real time clock, crystal, power-fail control circuit and lithium energy source Clock registers are accessed identical to the static RAM. These registers are resident in the sixteen top RAM locations Totally nonvolatile with over 10 years of operation in the absence of power Precision Power-On Reset Programmable Watchdog Timer and RTC Alarm BCD coded year, month, date, day, hours, minutes, and seconds with automatic leap year compensation valid up to the year 2100 Battery voltage level indicator flag Power-fail write protection allows for ±10% Vcc power supply tolerance Lithium energy source is electrically disconnected to retain freshness until power is applied for the first time ORDERING INFORMATION DS1543-XXX (5V) -70 70 ns access -100 100 ns access *DS1543W-XXX (3.3V) -120 120 ns access -150 150 ns access PRELIMINARY DS1543 64k NV Timekeeping RAM PIN ASSIGNMENT RST A12 A7 A6 A5 A4 A3 A2 A1 A0 DQ0 DQ1 DQ2 GND 1 2 3 4 5 6 7 8 9 10 11 12 13 14 28 VCC 27 WE 26 IRQ/FT 25 A8 24 A9 23 A11 22 OE 21 A10 20 CE 19 DQ7 18 DQ6 17 DQ5 16 DQ4 15 DQ3 28-Pin Encapsulated Package (700 Mil Extended) PIN DESCRIPTION A0-A12 - Address Input DQ0-DQ7 - Data Input/Outputs IRQ \FT - Interrupt, Frequency Test Output (Open-Drain) RST - Power-On Reset Output (Open-Drain) CE - Chip Enable OE - Output Enable WE VCC GND NC - Write Enable - Power Supply Input - Ground - No Connection 1 of 17 081000 DS1543 DESCRIPTION The DS1543 is a ...