Pre-Production
FM33256/FM3316
3V Integrated Processor Companion with Memory
Features
High Integration Device Replaces Multiple Parts
•
Serial Nonvolatile Memory
•
Real-time Clock (RTC) with Alarm
•
Low V
DD
Detection Drives Reset
•
Watchdog Window Timer
•
Early Power-Fail Warning/NMI
•
16-bit Nonvolatile Event Counter
•
Serial Number with Write-lock for Security
Ferroelectric Nonvolatile RAM
•
256Kb and 16Kb versions
•
Unlimited Read/Write Endurance
•
45 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
•
Software Calibration
•
Supports Battery or Capacitor Backup
Processor Companion
•
Active-low Reset Output for V
DD
and Watchdog
•
Programmable Low-V
DD
Reset Thresholds
•
Manual Reset Filtered and Debounced
•
Programmable Watchdog Window Timer
•
Nonvolatile Event Counter Tracks System
Intrusions or other Events
•
Comparator for Power-Fail Interrupt or Other Use
•
64-bit Programmable Serial Number with Lock
Fast SPI Interface
•
Up to 16 MHz Maximum Bus Frequency
•
RTC, Supervisor Controlled via SPI Interface
•
SPI Mode 0 & 3 (CPOL, CPHA=0,0 & 1,1)
Easy to Use Configurations
•
Operates from 2.7 to 3.6V
•
Small Footprint “Green” 14-pin SOIC (-G)
•
Low Operating Current, 50µA Standby Current
•
-40°C to +85°C Operation
•
Underwriters Laboratory (UL) Recognized
Description
The FM33256 and FM3316 are devices that integrate
F-RAM memory with the most commonly needed
functions for processor-based systems. Major
features include nonvolatile memory, real-time clock,
low-V
DD
reset, watchdog timer, nonvolatile event
counter, lockable 64-bit serial number area, and
general purpose comparator that can be used for a
power-fail (NMI) interrupt or other purpose. The
devices operate from 2.7 to 3.6V.
Each FM33xx provides nonvolatile RAM available in
memory capacity of 16Kb and 256Kb. 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 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.
The processor companion includes commonly needed
CPU support functions. Supervisory functions
include a reset output signal controlled by either a
low V
DD
condition or a watchdog timeout. /RST goes
active when V
DD
drops below a programmable
threshold and remains active for 100 ms (max.) after
V
DD
rises above the trip point. A programmable
watchdog timer runs from 60 ms to 1.8 seconds. The
timer may also be programmed for a delayed start,
which functions as a window timer. The watchdog
timer is optional, but if enabled it will assert the reset
signal for 100 ms if not restarted by the host within
the time window. A flag-bit indicates the source of
the reset.
A comparator on PFI compares an external input pin
to the onboard 1.5V reference. This is useful for
generating a power-fail interrupt (NMI) but can be
used for any purpose. The family also includes a
programmable 64-bit serial number that can be
locked making it unalterable. Additionally it offers an
event counter that tracks the number of rising or
falling edges detected on a dedicated input pin. The
counter can be programmed to be non-volatile under
V
DD
power or battery-backed using only V
BAK
. If
V
BAK
is connected to a battery or capacitor, then
events will be counted even in the absence of V
DD
.
Ramtron International Corporation
1850 Ramtron Drive, Colorado Springs, CO 80921
(800) 545-FRAM, (719) 481-7000
http://www.ramtron.com
Page 1 of 28
This is a product in the pre-production phase of development. Device
characterization is complete and Ramtron does not expect to change the
specifications. Ramtron will issue a Product Change Notice if any
specification changes are made.
Rev. 2.0
Feb. 2009
RAMTRON [ RAMTRON INTERNATIONAL CORPORATION ]
