[RAMTRON]

Description
The FM31xxx 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, realtime 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 2.7 to 5.5V.

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

Ferroelectric Nonvolatile RAM
• 4Kb, 16Kb, 64Kb, and 256Kb versions
• Unlimited Read/Write Endurance
• 10 year Data Retention
• NoDelay™ Writes

Real-time Clock/Calendar
• Backup Current under 1 µA
• Seconds through Centuries in BCD format
• Tracks Leap Years through 2099
• Uses Standard 32.768 kHz Crystal (6pF)
• Software Calibration
• Supports Battery or Capacitor Backup

Processor Companion
• Active-low Reset Output for VDD and Watchdog
• Programmable VDD Reset Trip Point
• Manual Reset Filtered and De-bounced
• 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

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

Easy to Use Configurations
• Operates from 2.7 to 5.5V
• Small Footprint 14-pin SOIC
• Low Operating Current
• -40°C to +85°C Operation