FM33256B-G Cypress Semiconductor, FM33256B-G Datasheet - Page 9

• Manufacturer Part Number: FM33256B-G
• Description: Real Time Clock 256Kb F-RAM Processor Companion
• Manufacturer: Cypress Semiconductor

Specifications of FM33256B-G

• Rohs: yes
• Supply Voltage - Max: 3.6 V
• Supply Voltage - Min: 2.7 V
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Package / Case: SOIC-14
• Factory Pack Quantity: 56

Backup Power
The real-time clock/calendar is intended to be
permanently powered. When the primary system
power fails, the voltage on the V
When V
will switch to the backup power supply on V
clock operates at extremely low current in order to
maximize battery or capacitor life. However, an
advantage of combining a clock function with FRAM
memory is that data is not lost regardless of the
backup power source.
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.
Rev. 3.0
Aug. 2012
CF
DD
Note: The minimum V
characterized at -40°C and +85°C but is not
100% tested.
Figure 10. I
is less 2.5V, the RTC (and event counters)
Years
8 bits
32.768 kHz
crystal
BAK
vs. V
Months
BAK
BAK
5 bits
Figure 9. Real-time Clock Core Block Diagram
DD
Voltage
voltage has been
pin will drop.
BAK
. The
6 bits
Date
User Registers
Oscillator
3 bits
Days
/OSCEN
The I
(see DC parametric table). Figure 10 shows I
function of V
calculating backup time when a capacitor is used as
the V
The minimum V
temperature. The user can expect the minimum V
voltage to be 1.23V at +85°C and 1.90V at -40°C.
The tested limit is 1.55V at +25°C.
Hours
6 bits
BAK
BAK
Figure 11. V
source.
current varies with temperature and voltage
Divider
Clock
1850 Ramtron Drive, Colorado Springs, CO 80921
FM33256B SPI Companion w/ FRAM
BAK
Minutes
7 bits
BAK
512 Hz or
SW out
. These curves are useful for
Ramtron International Corporation
BAK
1 Hz
voltage varies linearly with
(min.) vs Temperature
(800) 545-FRAM, [phone]
Seconds
Update
Logic
7 bits
W
www.ramtron.com
Page 9 of 28
R
BAK
as a
BAK