FM31278 Datasheet, PDF (1/26 Pages) Ramtron International Corporation – 5V Integrated Processor Companion with Memory

FM31278/FM31276
5V Integrated Processor Companion with Memory
Features
High Integration Device Replaces Multiple Parts
Serial Nonvolatile Memory
Real-time Clock (RTC)
Low Voltage Reset
Watchdog Timer
Early Power-Fail Warning/NMI
Two 16-bit Event Counters
Serial Number with Write-lock for Security
Processor Companion
Active-low Reset Output for V_DD and Watchdog
Programmable V_DD Reset Trip Point
Manual Reset Filtered and Debounced
Programmable Watchdog Timer
Dual Battery-backed Event Counter Tracks
System Intrusions or other Events
Comparator for Early Power-Fail Interrupt
64-bit Programmable Serial Number with Lock
Ferroelectric Nonvolatile RAM
64Kb and 256Kb versions
Virtually Unlimited Read/Write Endurance
38 year Data Retention (+75 C)
NoDelay™ Writes
Fast Two-wire Serial Interface
Up to 1 MHz Maximum Bus Frequency
Supports Legacy Timing for 100 kHz & 400 kHz
Device Select Pins for up to 4 Memory Devices
RTC, Supervisor Controlled via 2-wire Interface
Real-time Clock/Calendar
Backup Current at 2V, 1.15 A (max.) at +25°C
Seconds through Centuries in BCD format
Tracks Leap Years through 2099
Uses Standard 32.768 kHz Crystal (12.5pF)
Software Calibration
Supports Battery or Capacitor Backup
Easy to Use Configurations
Operates from 4.0 to 5.5V
14-pin “Green”/RoHS SOIC package (-G)
Low Operating Current
-40 C to +85 C Operation
Underwriters Laboratory (UL) Recognized
Description
The FM3127x is a family of integrated devices that
includes the most commonly needed functions for
processor-based systems. Major features include
nonvolatile memory available in various sizes, real-
time clock, low-VDD reset, watchdog timer,
nonvolatile event counter, lockable 64-bit serial
number area, and general purpose comparator that
can be used for an early power-fail (NMI) interrupt or
other purpose. The family operates from 4.0 to 5.5V.
Each FM3127x provides nonvolatile RAM available
in sizes including 64Kb and 256Kb versions. Fast
write speed and unlimited endurance allow the
memory to serve as extra RAM or conventional
nonvolatile storage. This memory is truly nonvolatile
rather than battery backed.
The processor companion includes commonly needed
CPU support functions. Supervisory functions
include a reset output signal controlled by either a
low VDD condition or a watchdog timeout. /RST
goes active when VDD drops below a programmable
threshold and remains active for 100 ms after VDD
rises above the trip point. A programmable watchdog
timer runs from 100 ms to 3 seconds. The watchdog
timer is optional, but if enabled it will assert the reset
signal for 100 ms if not restarted by the host before
the timeout. A flag-bit indicates the source of the
reset.
The real-time clock (RTC) provides time and date
information in BCD format. It can be permanently
powered from external backup voltage source, either
a battery or a capacitor. The timekeeper uses a
common external 32.768 kHz crystal and provides a
calibration mode that allows software adjustment of
timekeeping accuracy.
This product conforms to specifications per the terms of the Ramtron standard warranty. The product has completed Ramtron’s
internal qualification testing and has reached production status.
Cypress Semiconductor Corporation • 198 Champion Court • San Jose, CA 95134-1709 • 408-943-2600
Document Number: 001-86393 Rev. *B
Revised May 02, 2013