FM3104-G Ramtron, FM3104-G Datasheet - Page 7

• Manufacturer Part Number: FM3104-G
• Description: IC, FRAM, 4KBIT, 1MHZ, SOIC-14
• Manufacturer: Ramtron

Specifications of FM3104-G

• Memory Size: 4Kbit
• Ic Interface Type: 2 Wire, Serial
• Supply Voltage Range: 2.7V To 5.5V
• Memory Case Style: SOIC
• No. Of Pins: 14
• Operating Temperature Range: -40°C To +85°C
• Threshold Voltage: 4.4V
• Number Of Voltages Monitored: 4
• Monitored Voltage: 2.6 V, 2.9 V, 3.9 V, 4.4 V
• Output Type: Active Low, Open Drain
• Manual Reset: Resettable
• Watchdog: Watchdog
• Battery Backup Switching: Backup
• Power-up Reset Delay (typ): 200 ms
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 2.7 V
• Supply Current (typ): 1500 uA
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: SOIC-14
• Minimum Operating Temperature: - 40 C
• Power Fail Detection: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

to be loaded into the timekeeper core. W is used for
writing new time values. Users should be certain not
to load invalid values, such as FFh, to the
timekeeping registers. Updates to the timekeeping
core occur continuously except when locked.
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.
The I
(see DC parametric table). The following graph
shows I
useful for 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. The minimum
V
+85°C but is not 100% tested.
Rev. 2.0
Jan. 2011
BAK
BAK
voltage has been characterized at -40°C and
Figure 8. V
BAK
DD
current varies with temperature and voltage
Figure 7. I
is less 2.5V, the RTC (and event counters)
as a function of V
BAK
BAK
BAK
source.
BAK
(min.) vs. Temperature
voltage varies linearly with
vs. V
BAK
BAK
. These curves are
Voltage
DD
pin will drop.
BAK
. The
BAK
Trickle Charger
To facilitate capacitor backup the V
optionally provide a trickle charge current. When the
VBC bit, register 0Bh bit 2, is set to 1 the V
will source approximately 15 µA until V
V
charges the capacitor to V
diode and resistor charger. In 5V systems, it provides
the same convenience and also prevents the user from
exceeding the V
In the case where no battery is used, the V
should be tied according to the following conditions:
Although V
recommended if the companion is used. None of the
companion functions will operate below about 2.5V.
the VBC bit to 0 to prevent battery charging. The
V
resistor as a safety element.
BAK
DD
• For 3.3V systems, V
• For 5V systems, attach a 1 µF capacitor to V
Note: systems using lithium batteries should clear
or 3.75V whichever is less. In 3V systems, this
This assumes V
and turn the trickle charger on. The V
will charge to the internal backup voltage which
regulates itself to about 3.6V. V
be tied to 5V since the V
will be exceeded. A 1 µF capacitor will keep
the companion functions working for about 1.5
second.
circuitry includes an internal 1 K
BAK
BAK
may be connected to V
maximum voltage specification.
DD
does not exceed 3.75V.
BAK
DD
BAK
should be tied to V
without an external
FM3104/16/64/256
(max) specification
BAK
SS
BAK
BAK
, this is not
should not
Page 7 of 26
Ω
pin can
BAK
BAK
BAK
reaches
series
BAK
pin
pin
pin
DD
.