ETC FM3135

Product Concept
FM3135
Integrated RTC/Alarm/FRAM & Embedded Crystal
Features
High Integration Device Replaces Multiple Parts
• Serial Nonvolatile Memory
• Real-time Clock (RTC) with Alarm
• Clock Output (Programmable frequency)
64Kb Ferroelectric Nonvolatile RAM
• Internally Organized as 8Kx8
• Unlimited Read/Write Endurance
• 10 year Data Retention
• NoDelay™ Writes
Fast Two-wire Serial Interface
• Up to 1 MHz Maximum Bus Frequency
• Supports Legacy Timing for 100 kHz & 400 kHz
• RTC & FRAM Controlled via 2-wire Interface
Description
The FM3135 integrates a real-time clock (RTC) and
FRAM nonvolatile memory. The 32.768kHz crystal
is embedded inside the package. The device operates
from 2.7 to 3.6V.
The FM3135 provides nonvolatile FRAM which
features fast write speed and unlimited endurance.
This allows the memory to serve as extra RAM for
the system microcontroller 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 crystal
integral to the package and provides a calibration
mode that allows software adjustment of timekeeping
accuracy.
Real-time Clock/Calendar
• Embedded 32.768 kHz Crystal
• Backup Current under 1 µA
• Seconds through Centuries in BCD format
• Tracks Leap Years through 2099
• Software Calibration
• Supports Battery or Capacitor Backup
Easy to Use Configurations
• Operates from 2.7 to 3.6V
• 20-pin “Green”/RoHS SOIC (-G)
• Low Operating Current
• Industrial Temperature -40°C to +85°C
Pin Configuration
NC
NC
NC
NC
NC
NC
VBAK
VSS
SDA
SCL
Pin Name
ACS
SDA
SCL
VBAK
VDD
VSS
1
20
2
19
3
18
4
17
5
16
6
15
7
8
14
13
9
12
10
11
NC
NC
NC
NC
NC
NC
NC
NC
VDD
ACS
Function
Alarm/Calibration/SqWave
Serial Data
Serial Clock
Battery-Backup Supply
Supply Voltage
Ground
Ordering Information
FM3135-G
This is a product concept that is being considered for product development.
Functionality, pinout, timing specifications are not fixed. Ramtron reserves
the right to change or discontinue this product without notice
Rev. 0.1
Dec. 2006
“Green” 20-pin SOIC
Ramtron International Corporation
1850 Ramtron Drive, Colorado Springs, CO 80921
(800) 545-FRAM, (719) 481-7000
http://www.ramtron.com
Page 1 of 21
FM3135 Integrated RTC/Alarm/FRAM & Embedded Crystal
FRAM
Array
2-Wire
Interface
SCL
SDA
LockOut
VSW
Special
Function
Registers
RTC Registers
RTC Cal.
RTC
-
Alarm
+
VDD
Switched Power
Alarm
512Hz/SQW
VBAK
Nonvolatile
ACS
Battery Backed
Figure 1. Block Diagram
Pin Descriptions
Pin Name
ACS
Type
Output
SDA
I/O
SCL
Input
VBAK
Supply
VDD
VSS
Supply
Supply
Rev. 0.1
Dec. 2006
Pin Description
Alarm/Calibration/SquareWave: This is an open-drain output that requires an external
pullup resistor. The alarm, calibration, and square wave functions all share this output.
In Alarm mode, this pin acts as the active-low alarm output. In Calibration mode, a 512
Hz square-wave is driven out. In SquareWave mode, the user may select a frequency of
1, 512, 4096, or 32768 Hz to be used as a continuous output. Refer to Table 3. Control
Bit Settings for ACS Pin to determine the bit settings for each mode.
Serial Data & Address: This is a bi-directional line for the two-wire interface. It is
open-drain and is intended to be wire-OR’d with other devices on the two-wire bus. The
input buffer incorporates a Schmitt trigger for noise immunity and the output driver
includes slope control for falling edges. A pull-up resistor is required.
Serial Clock: The serial clock line for the two-wire interface. Data is clocked out of the
part on the falling edge, and data into the device on the rising edge. The SCL input also
incorporates a Schmitt trigger input for noise immunity.
Backup supply voltage: A 3V battery or a large value capacitor. If no backup supply is
used, this pin should be tied to VSS.
Supply Voltage.
Ground
Page 2 of 21
FM3135 Integrated RTC/Alarm/FRAM & Embedded Crystal
Overview
Real-Time Clock Operation
The FM3135 device combines a serial nonvolatile
RAM with a real-time clock (RTC) and alarm. These
complementary but distinct functions share a
common interface in a single package. Although
monolithic, the product is organized as two logical
devices, the FRAM memory and the RTC/alarm.
From the system perspective, they appear to be two
separate devices with unique IDs on the serial bus.
The real-time clock (RTC) is a timekeeping device
that can be battery or capacitor backed for
permanently-powered operation. It offers a software
calibration feature that allows high accuracy.
The memory is organized as a stand-alone 2-wire
nonvolatile memory with a standard device ID value.
The real-time clock and alarm are accessed with a
separate 2-wire device ID. This allows clock/calendar
data to be read while maintaining the most recently
used memory address. The clock and alarm are
controlled by 15 special function registers. The
registers are maintained by the power source on the
VBAK pin, allowing them to operate from battery or
backup capacitor power when VDD drops below a set
threshold. Each functional block is described below.
Memory Operation
The FM3135 integrates a 64Kb FRAM. The memory
is organized in bytes, 8192 addresses of 8 bits each.
The memory is based on FRAM technology.
Therefore it can be treated as RAM and is read or
written at the speed of the two-wire bus with no
delays for write operations. It also offers effectively
unlimited write endurance unlike other nonvolatile
memory technologies. The two-wire interface
protocol is described further on page 12.
The memory array can be write-protected by
software. Two bits (WP0, WP1) in register 0Eh
control the protection setting as shown in the
following table. Based on the setting, the protected
addresses cannot be written and the 2-wire interface
will not acknowledge any data to protected addresses.
The special function registers containing these bits
are described in detail below.
Table 1. FRAM Write-Protect
Write-Protect Range
WP1
None
0
Bottom 1/4
0
Bottom 1/2
1
Full array
1
WP0
0
1
0
1
The WP bits are battery-backed. On a powerup
without a backup source, the WP bits are cleared to a
‘0’ state.
The RTC consists of an oscillator, clock divider, and
a register system for user access. It divides down the
32.768 kHz time-base and provides a minimum
resolution of seconds (1Hz). Static registers provide
the user with read/write access to the time values. It
includes registers for seconds, minutes, hours, dayof-the-week, date, months, and years. A block
diagram (Figure 2) illustrates the RTC function.
The user registers are synchronized with the
timekeeper core using R and W bits in register 00h
described below. Changing the R bit from 0 to 1
transfers timekeeping information from the core into
holding registers that can be read by the user. If a
timekeeper update is pending when R is set, then the
core will be updated prior to loading the user
registers. The registers are frozen and will not be
updated again until the R bit is cleared to ‘0’. R is
used to read the time.
Setting the W bit to ‘1’ locks the user registers.
Clearing it to a ‘0’ causes the values in the user
registers 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. All
timekeeping registers must be initialized at the first
powerup or when the LB bit is set. See the
description of the LB bit on page 11.
Backup Power
The real-time clock/calendar is intended to be
permanently powered. When the primary system
power fails, the voltage on the VDD pin will drop.
When VDD is less than VSW, the RTC will switch to
the backup power supply on VBAK. The 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.
If a battery is applied without a VDD power supply,
the device has been designed to ensure the IBAK
current does not exceed the 1µA maximum limit.
Trickle Charger
To facilitate capacitor backup the VBAK pin can
optionally provide a trickle charge current. When the
Rev. 0.1
Dec. 2006
Page 3 of 21
FM3135 Integrated RTC/Alarm/FRAM & Embedded Crystal
• In the case where no battery is used, the VBAK
pin should be tied to VSS.
VBC bit (register 0Eh, bit 2) is set to a ‘1’, the VBAK
pin will source approximately 80 µA until VBAK
reaches VDD. This charges the capacitor to VDD
without an external diode and resistor charger.
There is a Fast Charge mode which is enabled by the
FC bit (register 0Eh, bit 1). In this mode the trickle
charger current is set to approximately 1 mA,
allowing a large backup capacitor to charge more
quickly.
! Note: systems using lithium batteries should clear
the VBC bit to 0 to prevent battery charging. The
VBAK circuitry includes an internal 1 KΩ series
resistor as a safety element.
512 Hz or
SW out
/OSCEN
32.768 kHz
crystal
CF
Years
8 bits
Months
5 bits
Clock
Divider
Oscillator
Date
6 bits
Hours
6 bits
1 Hz
Minutes
7 bits
W
Update
Logic
Seconds
7 bits
Days
3 bits
User Interface Registers
R
Figure 2. Real-Time Clock Core Block Diagram
Calibration
When the CAL bit in register 00h is set to ‘1’, the
clock enters calibration mode. In calibration mode,
the ACS output pin is dedicated to the calibration
function and the power fail output is temporarily
unavailable. Calibration operates by applying a
digital correction to the counter based on the
frequency error. In this mode, the ACS pin is driven
with a 512 Hz (nominal) square wave. Any measured
deviation from 512 Hz translates into a timekeeping
error. The user converts the measured error in ppm
and writes the appropriate correction value to the
calibration register. The correction factors are listed
in the table below. Positive ppm errors require a
negative adjustment that removes pulses. Negative
ppm errors require a positive correction that adds
pulses. Positive ppm adjustments have the CALS
(sign) bit set to ‘1’, whereas negative ppm
adjustments have CALS = 0. After calibration, the
Rev. 0.1
Dec. 2006
clock will have a maximum error of ± 2.17 ppm or
0.09 minutes per month at the calibrated
temperature.
±
The calibration setting is battery-backed and must be
reloaded should the backup source fail. It is accessed
with bits CAL.4-0 in register 01h. This value only
can be written when the CAL bit is set to a ‘1’. To
exit the calibration mode, the user must clear the
CAL bit to a ‘0’. When the CAL bit is ‘0’, the ACS
pin will revert to another function as defined in
Table 3. Control Bit Settings for ACS Pin.
Page 4 of 21
FM3135 Integrated RTC/Alarm/FRAM & Embedded Crystal
Table 2. Calibration Adjustments
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
Positive Calibration for slow clocks: Calibration will achieve ± 2.17 PPM after calibration
Measured Frequency Range
Error Range (PPM)
Min
Max
Min
Max
Program Calibration Register to:
512.0000
511.9989
0
2.17
000000
511.9989
511.9967
2.18
6.51
100001
511.9967
511.9944
6.52
10.85
100010
511.9944
511.9922
10.86
15.19
100011
511.9922
511.9900
15.20
19.53
100100
511.9900
511.9878
19.54
23.87
100101
511.9878
511.9856
23.88
28.21
100110
511.9856
511.9833
28.22
32.55
100111
511.9833
511.9811
32.56
36.89
101000
511.9811
511.9789
36.90
41.23
101001
511.9789
511.9767
41.24
45.57
101010
511.9767
511.9744
45.58
49.91
101011
511.9744
511.9722
49.92
54.25
101100
511.9722
511.9700
54.26
58.59
101101
511.9700
511.9678
58.60
62.93
101110
511.9678
511.9656
62.94
67.27
101111
511.9656
511.9633
67.28
71.61
110000
511.9633
511.9611
71.62
75.95
110001
511.9611
511.9589
75.96
80.29
110010
511.9589
511.9567
80.30
84.63
110011
511.9567
511.9544
84.64
88.97
110100
511.9544
511.9522
88.98
93.31
110101
511.9522
511.9500
93.32
97.65
110110
511.9500
511.9478
97.66
101.99
110111
511.9478
511.9456
102.00
106.33
111000
511.9456
511.9433
106.34
110.67
111001
511.9433
511.9411
110.68
115.01
111010
511.9411
511.9389
115.02
119.35
111011
511.9389
511.9367
119.36
123.69
111100
511.9367
511.9344
123.70
128.03
111101
511.9344
511.9322
128.04
132.37
111110
511.9322
511.9300
132.38
136.71
111111
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
Negative Calibration for fast clocks: Calibration will achieve ± 2.17 PPM after calibration
Measured Frequency Range
Error Range (PPM)
Min
Max
Min
Max
Program Calibration Register to:
512.0000
512.0011
0
2.17
000000
512.0011
512.0033
2.18
6.51
000001
512.0033
512.0056
6.52
10.85
000010
512.0056
512.0078
10.86
15.19
000011
512.0078
512.0100
15.20
19.53
000100
512.0100
512.0122
19.54
23.87
000101
512.0122
512.0144
23.88
28.21
000110
512.0144
512.0167
28.22
32.55
000111
512.0167
512.0189
32.56
36.89
001000
512.0189
512.0211
36.90
41.23
001001
512.0211
512.0233
41.24
45.57
001010
512.0233
512.0256
45.58
49.91
001011
512.0256
512.0278
49.92
54.25
001100
512.0278
512.0300
54.26
58.59
001101
512.0300
512.0322
58.60
62.93
001110
512.0322
512.0344
62.94
67.27
001111
512.0344
512.0367
67.28
71.61
010000
512.0367
512.0389
71.62
75.95
010001
512.0389
512.0411
75.96
80.29
010010
512.0411
512.0433
80.30
84.63
010011
512.0433
512.0456
84.64
88.97
010100
512.0456
512.0478
88.98
93.31
010101
512.0478
512.0500
93.32
97.65
010110
512.0500
512.0522
97.66
101.99
010111
512.0522
512.0544
102.00
106.33
011000
512.0544
512.0567
106.34
110.67
011001
Rev. 0.1
Dec. 2006
Page 5 of 21
FM3135 Integrated RTC/Alarm/FRAM & Embedded Crystal
26
27
28
29
30
31
512.0567
512.0589
512.0611
512.0633
512.0656
512.0678
512.0589
512.0611
512.0633
512.0656
512.0678
512.0700
110.68
115.02
119.36
123.70
128.04
132.38
Alarm
The alarm function compares user-programmed
alarm values to the corresponding RTC time/date
values. When a match occurs, an alarm event occurs.
The alarm event sets an internal flag AF (register
00h, bit 6) and drives the ACS pin low, if the
appropriate control bits are set in registers 00h and
0Eh. See Table 3. The alarm condition on the ACS
pin and the AF bit are cleared by reading register
00h.
The alarm operates under VDD or VBAK power. If the
system controller is being used to detect an alarm
while the FM3135 is powered on VBAK only, the ACS
pin may cause extra IBAK current when the alarm is
activated. To avoid battery drain, the ACS pin can be
tri-stated by reading the AF flag, located in the
RTC/Alarm Control register 00h.
There are five alarm match fields. They are Month,
Date, Hours, Minutes, and Seconds. Each of these
fields also has a Match bit that is used to determine if
the field is used in the alarm match logic. Setting the
Match bit to ‘0’ indicates that the corresponding field
will be used in the match process.
Depending on the Match bits, the alarm can occur as
specifically as one particular second on one day of
the month, or as frequently as once per second
continuously. The MSB of each Alarm register is a
Match bit. Examples of the Match bit settings are
shown in Table 4. Alarm Match Bit Examples.
Selecting none of the match bits (all ‘1’s) indicates
that no match is required. The alarm occurs every
second. Setting the match select bit for seconds to ‘0’
causes the logic to match the seconds alarm value to
the current time of day. Since a match will occur for
only one value per minute, the alarm occurs once per
minute. Likewise setting the seconds and minutes
match select bits causes an exact match of these
values. Thus, an alarm will occur once per hour.
Setting seconds, minutes, and hours causes a match
once per day. See Table 4 for other alarm setting
examples.
Rev. 0.1
Dec. 2006
115.01
119.35
123.69
128.03
132.37
136.71
011010
011011
011100
011101
011110
011111
Function of the ACS Pin
The ACS pin is a multifunction pin. The alarm,
calibration, and square wave functions all share this
output. There are two ways a user can detect an alarm
event, by reading the AF flag or by monitoring the
ACS pin. An interrupt pin on the host processor may
be used to detect an alarm event. The AF flag in the
register 00h (bit 6) will indicate that a time/date
match has occurred. When a match occurs, the AF
bit will be set to ‘1’ and the ACS pin will drive low.
The flag and ACS pin will remain in this state until
the RTC/Alarm Control register is read which clears
the AF bit.
Table 3 that shows the relationship between register
control settings and the function of the ACS pin.
Table 3. Control Bit Settings for ACS Pin
State of Register Bit
Function of
ACS pin
CAL AEN AL/SW
0
1
1
/Alarm
0
X
0
Sq Wave out
1
X
X
512 Hz out
0
0
1
Hi-Z
Page 6 of 21
FM3135 Integrated RTC/Alarm/FRAM & Embedded Crystal
Cal Output/SquareWave Output
When the RTC calibration mode is invoked by
setting the CAL bit (register 00h, bit 2), the ACS
output pin will be driven with a 512 Hz square wave
and the alarm will continue to operate. Since most
users only invoke the calibration mode during
production, this should have no impact on the
otherwise normal operation of the alarm.
The ACS output may also be used to drive the system
with a continuous frequency. The AL/SW bit
(register 0Eh, bit 7) must be a ‘0’. A user-selectable
frequency is provided by F0 and F1 (register 0Eh,
bits 5 and 6). The frequencies are 1, 512, 4096, and
32768 Hz. If a continuous frequency output is
enabled by using the 512Hz or SquareWave out
functions, the alarm function will not be available.
VBAK
1M Ω
FM3135
ACS
MCU
Figure 4. ACS Pin Requires Pullup
The ACS pin is an open-drain output that needs to be
pulled up to a supply. The ACS pin and pullup
resistor draws current only when the alarm is
triggered.
Table 4. Alarm Match Bit Examples
Seconds
Minutes
Hours
Date
Months
Alarm condition
1
1
1
1
1
No match required = alarm 1/second
0
1
1
1
1
Alarm when seconds match = alarm 1/minute
0
0
1
1
1
Alarm when seconds, minutes match = alarm 1/hour
0
0
0
1
1
Alarm when seconds, minutes, hours match = alarm 1/date
0
0
0
0
1
Alarm when seconds, minutes, hours, date match = alarm 1/month
Rev. 0.1
Dec. 2006
Page 7 of 21
FM3135 Integrated RTC/Alarm/FRAM & Embedded Crystal
Register Map
The RTC, alarm, and other functions are accessed via 15 special function registers mapped to a separate 2-wire
device ID. The interface protocol is described below. The registers contain timekeeping data, control bits, or
information flags. A description of each register follows the summary table below.
Register Map Summary Table
Address
0Eh
0Dh
0Ch
0Bh
0Ah
09h
08h
07h
06h
05h
04h
03h
02h
01h
00h
D7
AL/SW
/Match
/Match
/Match
/Match
/Match
0
0
0
0
0
0
/OSCEN
LB
D6
F1
0
0
0
D5
F0
0
D4
WP1
10 mo
10 date
Alarm 10 hours
Alarm 10 minutes
Alarm 10 seconds
10 years
0
0
10 mo
0
10 date
0
0
0
0
10 hours
10 minutes
10 seconds
CALS
CAL4
AF
CF
POR
D3
WP0
0
CAL3
AEN
D2
D1
VBC
FC
Alarm months
Alarm date
Alarm hours
Alarm minutes
Alarm seconds
years
months
date
day
hours
minutes
seconds
CAL2
CAL1
CAL
W
D0
TST
Function
Alarm & WP Control
Alarm Month
Alarm Date
Alarm Hours
Alarm Minutes
Alarm Seconds
RTC Years
CAL0
R
RTC Month
RTC Date
RTC Day
RTC Hours
RTC Minutes
RTC Seconds
CAL/Control
RTC/Alarm Control
Range
01-12
01-31
00-23
00-59
00-59
00-99
1-12
1-31
1-7
0-23
0-59
0-59
Note: When the device is first powered up, all registers should be treated as unknown and must be written.
Otherwise, unpredictable behavior may result.
Rev. 0.1
Dec. 2006
Page 8 of 21
FM3135 Integrated RTC/Alarm/FRAM & Embedded Crystal
Register Description
Address
Description
0Eh
Alarm & WP Control
AL/SW
F(1:0)
D7
D6
D5
D4
D3
D2
D1
D0
AL/SW
F1
F0
WP1
WP0
VBC
FC
TST
Alarm/Square Wave Select: When set to 1, the alarm controls the ACS pin as well as the AF flag. When set to 0,
the selected Square Wave Freq will be driven on the ACS pin, and an alarm match only sets the AF flag. Batterybacked, read/write.
Square Wave Freq Select: These bits select the frequency on the ACS pin when the CAL and AL/SW bits are
both 0. Battery-backed.
Setting
1 Hz
512 Hz
WP1,WP0
F(1:0)
00 (default)
01
F(1:0)
10
11
Write Protect. These bits control the write protection of the memory array. Battery-backed, read/write.
Write-Protect addresses
None
Bottom 1/4
Bottom 1/2
Full array
VBC
Setting
4096 Hz
32768 Hz
WP1
0
0
1
1
WP0
0
1
0
1
TST
VBAK Charger Control: Setting VBC to 1 (and FC=0) causes approx. 80 µA (1mA if FC=1) trickle charge
current to be supplied on VBAK. Clearing VBC to 0 disables the charge current. Battery-backed, read/write.
Fast Charge: Setting FC to 1 (and VBC=1) causes approx. 1mA trickle charge current to be supplied on VBAK.
Clearing VBC to 0 disables the charge current. Battery-backed, read/write.
Invokes factory test mode. Users should always set this bit to 0.
0Dh
Alarm – Month
FC
D7
D6
D5
D4
D3
D2
D1
D0
M
0
0
10 Month
Month.3
Month.2
Month.1
Month.0
/M
Contains the alarm value for the month and the mask bit to select or deselect the Month value.
Match. Setting this bit to a ‘0’ causes the Month value to be used in the alarm match logic. Setting this bit to a
‘1’ causes the match circuit to ignore the Month value. Battery-backed, read/write.
0Ch
Alarm – Date
D7
D6
D5
D4
D3
D2
D1
D0
M
0
10 date.1
10 date.0
Date.3
Date.2
Date.1
Date.0
/M
Contains the alarm value for the date and the mask bit to select or deselect the Date value.
Match: Setting this bit to a ‘0’ causes the Date value to be used in the alarm match logic. Setting this bit to a ‘1’
causes the match circuit to ignore the Date value. Battery-backed, read/write.
0Bh
Alarm – Hours
D7
D6
D5
D4
D3
D2
D1
D0
M
0
10 hours.1
10 hours.0
Hours.3
Hours2
Hours.1
Hours.0
/M
Contains the alarm value for the hours and the mask bit to select or deselect the Hours value.
Match: Setting this bit to a ‘0’ causes the Hours value to be used in the alarm match logic. Setting this bit to a ‘1’
causes the match circuit to ignore the Hours value. Battery-backed, read/write.
0Ah
Alarm – Minutes
/M
Rev. 0.1
Dec. 2006
D7
D6
D5
D4
D3
D2
D1
D0
M
10 min.2
10 min.1
10 min.0
Min.3
Min.2
Min.1
Min.0
Contains the alarm value for the minutes and the mask bit to select or deselect the Minutes value
Match: Setting this bit to a ‘0’ causes the Minutes value to be used in the alarm match logic. Setting this bit to a
‘1’ causes the match circuit to ignore the Minutes value. Battery-backed, read/write.
Page 9 of 21
FM3135 Integrated RTC/Alarm/FRAM & Embedded Crystal
09h
/M
08h
Alarm – Seconds
D7
D6
D5
D4
D3
D2
D1
D0
M
10 sec.2
10 sec.1
10 sec.0
Seconds.3
Seconds.2
Seconds.1
Seconds.0
Contains the alarm value for the seconds and the mask bit to select or deselect the Seconds value.
Match: Setting this bit to a ‘0’ causes the Seconds value to be used in the alarm match logic. Setting this bit to a
‘1’ causes the match circuit to ignore the Seconds value. Battery-backed, read/write.
Timekeeping – Years
D7
D6
D5
D4
D3
D2
D1
D0
10 year.3
10 year.2
10 year.1
10 year.0
Year.3
Year.2
Year.1
Year.0
Contains the lower two BCD digits of the year. Lower nibble contains the value for years; upper nibble contains
the value for 10s of years. Each nibble operates from 0 to 9. The range for the register is 0-99. Battery-backed,
read/write.
07h
Timekeeping – Months
D7
D6
D5
D4
D3
D2
D1
D0
0
0
0
10 Month
Month.3
Month.2
Month.1
Month.0
Contains the BCD digits for the month. Lower nibble contains the lower digit and operates from 0 to 9; upper
nibble (one bit) contains the upper digit and operates from 0 to 1. The range for the register is 1-12. Batterybacked, read/write.
06h
Timekeeping – Date of the month
D7
D6
D5
D4
D3
D2
D1
D0
0
0
10 date.1
10 date.0
Date.3
Date.2
Date.1
Date.0
Contains the BCD digits for the date of the month. Lower nibble contains the lower digit and operates from 0 to 9;
upper nibble contains the upper digit and operates from 0 to 3. The range for the register is 1-31. Battery-backed,
read/write.
05h
Timekeeping – Day of the week
D7
D6
D5
D4
D3
D2
D1
D0
0
0
0
0
0
Day.2
Day.1
Day.0
Lower nibble contains a value that correlates to day of the week. Day of the week is a ring counter that counts
from 1 to 7 then returns to 1. The user must assign meaning to the day value, as the day is not integrated with the
date. Battery-backed, read/write.
04h
Timekeeping – Hours
D7
D6
D5
D4
D3
D2
D1
D0
0
0
10 hours.1
10 hours.0
Hours.3
Hours2
Hours.1
Hours.0
Contains the BCD value of hours in 24-hour format. Lower nibble contains the lower digit and operates from 0 to
9; upper nibble (two bits) contains the upper digit and operates from 0 to 2. The range for the register is 0-23.
Battery-backed, read/write.
03h
Timekeeping – Minutes
D7
D6
D5
D4
D3
D2
D1
D0
0
10 min.2
10 min.1
10 min.0
Min.3
Min.2
Min.1
Min.0
Contains the BCD value of minutes. Lower nibble contains the lower digit and operates from 0 to 9; upper nibble
contains the upper minutes digit and operates from 0 to 5. The range for the register is 0-59. Battery-backed,
read/write.
02h
Timekeeping – Seconds
D7
D6
D5
D4
D3
D2
D1
D0
0
10 sec.2
10 sec.1
10 sec.0
Seconds.3
Seconds.2
Seconds.1
Seconds.0
Contains the BCD value of seconds. Lower nibble contains the lower digit and operates from 0 to 9; upper nibble
contains the upper digit and operates from 0 to 5. The range for the register is 0-59. Battery-backed, read/write.
01h
/OSCEN
Rev. 0.1
Dec. 2006
CAL/Control
D7
D6
D5
D4
D3
D2
D1
D0
OSCEN
-
CALS
CAL.4
CAL.3
CAL.2
CAL.1
CAL.0
Oscillator Enable. When set to 1, the oscillator is halted. When set to 0, the oscillator runs. Disabling the
oscillator can save battery power during storage. On an initial power-up of VDD with or without VBAK, this bit
is internally set to 1, which turns off the oscillator. Battery-backed, read/write.
Page 10 of 21
FM3135 Integrated RTC/Alarm/FRAM & Embedded Crystal
CALS
CAL.4-0
00h
LB
AF
CF
POR
AEN
CAL
W
R
Rev. 0.1
Dec. 2006
Calibration Sign: Determines if the calibration adjustment is applied as an addition to or as a subtraction from
the time-base. This bit can be written only when CAL=1. Battery-backed, read/write.
Calibration Code: These five bits control the calibration of the clock. These bits can be written only when
CAL=1. Battery-backed, read/write.
RTC/Alarm Control
D7
D6
D5
D4
D3
D2
D1
D0
LB
AF
CF
POR
AEN
CAL
W
R
Low Battery Flag: If the VBAK source drops to a voltage level insufficient to operate the RTC/alarm, this bit
will be set to ‘1’. All registers need to be re-initialized since the battery-backed register values should be
treated as unknown. The user should clear it to ‘0’ when initializing the system. Battery-backed. Read/Write
(internally set, user can clear bit by writing to a ‘0’).
Alarm Flag: This read-only bit is set to 1 when the time/date match the values stored in the alarm registers with
the Match bit(s) = 0. It is cleared when the RTC/Alarm Control register is read. Battery-backed.
Century Overflow Flag: This read-only bit is set to a 1 when the values in the years register overflows from 99
to 00. This indicates a new century, such as going from 1999 to 2000 or 2099 to 2100. The user should record
the new century information as needed. This bit is cleared when the RTC/Alarm Control register is read.
Battery-backed.
Power On Reset Flag: When VDD drops below VSW, the POR bit will be set to ‘1’. Battery-backed.
Read/Write (internally set, user can clear bit by writing to a ‘0’).
Alarm Enable: This bit enables the alarm function. When AEN is set (and CAL cleared), the ACS pin operates
as an active-low alarm and the AF flag function is enabled. The function of the ACS pin is detailed in Table 3.
When AEN is cleared, no new alarm events will occur but the AF flag and ACS pin will not be cleared.
Battery-backed, read/write.
Calibration Mode: When CAL is set to ‘1’, the clock enters calibration mode. When CAL is set to ‘0’, the clock
operates normally, and the ACS pin is controlled by the RTC alarm. Battery-backed, read/write.
Write RTC: Setting the W bit to ‘1’ freezes updates of the user timekeeping registers. The user can then write
them with updated values. Setting the W bit to ‘0’ causes the contents of the time registers to be transferred to
the timekeeping counters. Battery-backed, read/write.
Read RTC: Setting the R bit to ‘1’ copies a static image of the timekeeping core and place it into the user
registers. The user can then read them without concerns over changing values causing system errors. The R bit
going from ‘0’ to ‘1’ causes the timekeeping capture, so the bit must be returned to ‘0’ prior to reading again.
Battery-backed, read/write.
Page 11 of 21
FM3135 Integrated RTC/Alarm/FRAM & Embedded Crystal
By convention, any device that is sending data onto
the bus is the transmitter while the target device for
this data is the receiver. The device that is
controlling the bus is the master. The master is
responsible for generating the clock signal for all
operations. Any device on the bus that is being
controlled is a slave. The FM3135 is always a slave
device.
Two-wire Interface
The FM3135 employs an industry standard two-wire
bus that is familiar to many users. This product is
unique since it incorporates two logical devices in
one chip. Each logical device can be accessed
individually. Although monolithic, it appears to the
system software to be two separate products. One is
a memory device. It has a Slave Address (Slave ID =
1010b) that operates the same as a stand-alone
memory device. The second device is a real-time
clock and alarm which have a unique Slave Address
(Slave ID = 1101b).
The bus protocol is controlled by transition states in
the SDA and SCL signals. There are four conditions:
Start, Stop, Data bit, and Acknowledge. The figure
below illustrates the signal conditions that specify
the four states. Detailed timing diagrams are shown
in the Electrical Specifications section.
SCL
7
SDA
Stop
(Master)
0
Start
Data bits
Data bit Acknowledge
(Master)
(Transmitter)
(Transmitter) (Receiver)
Figure 4. Data Transfer Protocol
Start Condition
A Start condition is indicated when the bus master
drives SDA from high to low while the SCL signal is
high. All read and write transactions begin with a
Start condition. An operation in progress can be
aborted by asserting a Start condition at any time.
Aborting an operation using the Start condition will
ready the FM3135 for a new operation.
Stop Condition
A Stop condition is indicated when the bus master
drives SDA from low to high while the SCL signal is
high. All operations must end with a Stop condition.
If an operation is pending when a stop is asserted,
the operation will be aborted. The master must have
control of SDA (not a memory read) in order to
assert a Stop condition.
Data/Address Transfer
All data transfers (including addresses) take place
while the SCL signal is high. Except under the two
conditions described above, the SDA signal should
not change while SCL is high.
Acknowledge
The Acknowledge (ACK) takes place after the 8th
data bit has been transferred in any transaction.
Rev. 0.1
Dec. 2006
6
During this state the transmitter must release the
SDA bus to allow the receiver to drive it. The
receiver drives the SDA signal low to acknowledge
receipt of the byte. If the receiver does not drive
SDA low, the condition is a No-Acknowledge
(NACK) and the operation is aborted.
The receiver might NACK for two distinct reasons.
First is that a byte transfer fails. In this case, the
NACK ends the current operation so that the part can
be addressed again. This allows the last byte to be
recovered in the event of a communication error.
Second and most common, the receiver does not
send an ACK to deliberately terminate an operation.
For example, during a read operation, the FM3135
will continue to place data onto the bus as long as the
receiver sends ACKs (and clocks). When a read
operation is complete and no more data is needed,
the receiver must NACK the last byte. If the receiver
ACKs the last byte, this will cause the FM3135 to
attempt to drive the bus on the next clock while the
master is sending a new command such as a Stop.
Slave Address
The first byte that the FM3135 expects after a Start
condition is the slave address. As shown in figures
below, the slave address contains the Slave ID and a
bit that specifies if the transaction is a read or a
write.
Page 12 of 21
FM3135 Integrated RTC/Alarm/FRAM & Embedded Crystal
The FM3135 has two Slave Addresses (Slave IDs)
associated with two logical devices. To access the
memory device, bits 7-4 should be set to 1010b. The
other logical device within the FM3135 is the realtime clock and alarm. To access this device, bits 7-4
of the slave address should be set to 1101b. A bus
transaction with this slave address will not affect the
memory in any way. The figures below illustrate the
two Slave Addresses.
Bits 3 through 1 of the Slave Address must be logic
0. Bit 0 is the read/write bit. A ‘1’ indicates a read
operation, and a ‘0’ indicates a write operation.
Slave ID
1
7
0
1
0
0
0
0
R/W
6
5
4
3
2
1
0
Figure 5. Slave Address – Memory
Slave ID
1
1
7
6
0
1
0
0
0
R/W
5
4
3
2
1
0
Figure 6. Slave Address – RTC
Addressing Overview – Memory
After the FM3135 acknowledges the Slave Address,
the master can place the memory address on the bus
for a write operation. The address requires two bytes.
The first is the MSB (upper byte). The first 3 unused
address bits are don’t cares, but should be set to ‘0’
to maintain upward compatibility. Following the
MSB is the LSB (lower byte) which contains the
remaining eight address bits. The address is latched
internally. Each access causes the latched address to
be incremented automatically. The current address is
the value that is held in the latch, either a newly
written value or the address following the last access.
The current address will be held as long as VDD is
greater than VSW or until a new value is written.
Accesses to the clock do not affect the current
memory address. Reads always use the current
Rev. 0.1
Dec. 2006
address. A random read address can be loaded by
beginning a write operation as explained below.
After transmission of each data byte, just prior to the
Acknowledge, the FM3135 increments the internal
address. This allows the next sequential byte to be
accessed with no additional addressing externally.
After the last address is reached, the address latch
will roll over to 0000h. There is no limit to the
number of bytes that can be accessed with a single
read or write operation.
Addressing Overview – RTC/Alarm
The RTC/Alarm operates in a similar manner to the
memory, except that it uses only one byte of address.
Addresses 00h to 0Eh correspond to the RTC/Alarm
and control registers. Attempting to load addresses
above 0Eh is an illegal condition; the FM3135 will
return a NACK and abort the 2-wire transaction.
Data Transfer
After the address information has been transmitted,
data transfer between the bus master and the
FM3135 begins. For a read, the FM3135 will place 8
data bits on the bus then wait for an ACK from the
master. If the ACK occurs, the FM3135 will transfer
the next byte. If the ACK is not sent, the FM3135
will end the read operation. For a write operation, the
FM3135 will accept 8 data bits from the master then
send an Acknowledge. All data transfer occurs MSB
(most significant bit) first.
Memory Write Operation
All memory writes begin with a Slave Address, then
a memory address. The bus master indicates a write
operation by setting the slave address LSB to a ‘0’.
After addressing, the bus master sends each byte of
data to the memory and the memory generates an
Acknowledge condition. Any number of sequential
bytes may be written. If the end of the address range
is reached internally, the address counter will wrap
to 0000h. Internally, the actual memory write occurs
after the 8th data bit is transferred. It will be complete
before the Acknowledge is sent. Therefore, if the
user desires to abort a write without altering the
memory contents, this should be done using a Start
or Stop condition prior to the 8th data bit. The figures
below illustrate a single- and multiple-writes to
memory.
Page 13 of 21
FM3135 Integrated RTC/Alarm/FRAM & Embedded Crystal
Start
By Master
S
Stop
Address & Data
Slave Address
0
A
Address MSB
By FM3130
A
Address LSB
A
Data Byte
A
P
Acknowledge
Figure 7. Single Byte Memory Write
Start
Stop
Address & Data
By Master
S
By FM3130
Slave Address
0 A
Address MSB
A
Address LSB
A
Data Byte
A
Data Byte
A
P
Acknowledge
Figure 8. Multiple Byte Memory Write
Memory Read Operation
There are two types of memory read operations. They
are current address read and selective address read. In
a current address read, the FM3135 uses the internal
address latch to supply the address. In a selective
read, the user performs a procedure to first set the
address to a specific value.
Current Address & Sequential Read
As mentioned above the FM3135 uses an internal
latch to supply the address for a read operation. A
current address read uses the existing value in the
address latch as a starting place for the read
operation. The system reads from the address
immediately following that of the last operation.
To perform a current address read, the bus master
supplies a slave address with the LSB set to 1. This
indicates that a read operation is requested. After
receiving the complete device address, the FM3135
will begin shifting data out from the current address
on the next clock. The current address is the value
held in the internal address latch.
Beginning with the current address, the bus master
can read any number of bytes. Thus, a sequential read
is simply a current address read with multiple byte
transfers. After each byte the internal address counter
will be incremented.
Each time the bus master acknowledges a byte,
this indicates that the FM3135 should read out
the next sequential byte.
Rev. 0.1
Dec. 2006
There are four ways to terminate a read operation.
Failing to properly terminate the read will most likely
create a bus contention as the FM3135 attempts to
read out additional data onto the bus. The four valid
methods follow.
1.
2.
3.
4.
The bus master issues a NACK in the 9th clock
cycle and a Stop in the 10th clock cycle. This is
illustrated in the diagrams below and is
preferred.
The bus master issues a NACK in the 9th clock
cycle and a Start in the 10th.
The bus master issues a Stop in the 9th clock
cycle.
The bus master issues a Start in the 9th clock
cycle.
If the internal address reaches the top of memory, it
will wrap around to 0000h on the next read cycle.
The figures below show the proper operation for
current address reads.
Selective (Random) Read
There is a simple technique that allows a user to
select a random address location as the starting point
for a read operation. This involves using the first
three bytes of a write operation to set the internal
address followed by subsequent read operations.
To perform a selective read, the bus master sends out
the slave address with the LSB set to 0. This specifies
a write operation. According to the write protocol,
the bus master then sends the address bytes that are
loaded into the internal address latch. After the
FM3135 acknowledges the address, the bus master
Page 14 of 21
FM3135 Integrated RTC/Alarm/FRAM & Embedded Crystal
FM3135 will begin shifting data out from the current
register address on the next clock. Auto-increment
operates for the special function registers as with the
memory address. A current address read for the
registers look exactly like the memory except that the
device ID is different.
issues a Start condition. This simultaneously aborts
the write operation and allows the read command to
be issued with the slave address LSB set to a ‘1’. The
operation is now a read from the current address.
Read operations are illustrated below.
RTC/Alarm Write Operation
All RTC/Alarm writes operate in a similar manner to
memory writes. The distinction is that a different
device ID is used and only one byte address is needed
instead of two. Figure 12 illustrates a single byte
write to the RTC/Alarm.
The FM3135 contains two separate address registers,
one for the memory address and the other for the
register address. This allows the contents of one
address register to be modified without affecting the
current address of the other register. For example,
this would allow an interrupted read to the memory
while still providing fast access to an RTC register. A
subsequent memory read will then continue from the
memory address where it previously left off, without
requiring the load of a new memory address.
However, a write sequence always requires an
address to be supplied.
RTC/Alarm Read Operation
As with writes, a read operation begins with the
Slave Address. To perform a register read, the bus
master supplies a Slave Address with the LSB set to a
‘1’. This indicates that a read operation is requested.
After receiving the complete Slave Address, the
Start
By Master
No
Acknowledge
Address
Stop
Slave Address
S
By FM3130
1 A
Data Byte
Acknowledge
1
P
Data
Figure 9. Current Address Memory Read
By Master
Start
Address
No
Acknowledge
Acknowledge
Stop
S
Slave Address
By FM3130
1
A
Data Byte
A
Acknowledge
Data Byte
1
P
Data
Figure 10. Sequential Memory Read
Start
Address
By Master
Start
No
Acknowledge
Address
Stop
S
Slave Address
0 A
Address MSB
A
Address LSB
A
S
Slave Address
By FM3130
Acknowledge
1 A
Data Byte
1 P
Data
Figure 11. Selective (Random) Memory Read
Rev. 0.1
Dec. 2006
Page 15 of 21
FM3135 Integrated RTC/Alarm/FRAM & Embedded Crystal
By Master
S
By FM3135
Stop
Address & Data
Start
Slave Address
0 A 0 0 0 0
Address
A
Data Byte
A
P
Acknowledge
Figure 12. Register Byte Write
* Although not required, it is recommended that A7-A4 in the Register Address byte are
zeros in order to preserve compatibility with future devices.
Rev. 0.1
Dec. 2006
Page 16 of 21
FM3135 Integrated RTC/Alarm/FRAM & Embedded Crystal
Electrical Specifications
Absolute Maximum Ratings
Symbol
Description
VDD
Power Supply Voltage with respect to VSS
VIN
Voltage on any signal pin with respect to VSS
VBAK
TSTG
TLEAD
Backup Supply Voltage
Storage Temperature
Lead Temperature (Soldering, 10 seconds)
Ratings
-1.0V to +5.0V
-1.0V to +5.0V * and
VIN ≤ VDD+1.0V **
-1.0V to +4.5V
-55°C to + 125°C
300° C
** The “VIN < VDD+1.0V” restriction does not apply to the SCL, SDA, and ACS pins which do not employ a diode to VDD.
Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only,
and the functional operation of the device at these or any other conditions above those listed in the operational section of this
specification is not implied. Exposure to absolute maximum ratings conditions for extended periods may affect device reliability.
DC Operating Conditions (TA = -40° C to + 85° C, VDD = 2.7V to 3.6V unless otherwise specified)
Symbol
Parameter
Min
Typ
Max
VDD
Main Power Supply
2.7
3.6
IDD
VDD Supply Current
@ SCL = 100 kHz
150
@ SCL = 1 MHz
500
ISB
Standby Current
Trickle Charger Off (VBC=0)
50
Trickle Chrg On, Fast Chrg Off (VBC=1, FC=0)
190
Trickle Chrg On, Fast Chrg On (VBC=1, FC=1)
2600
VBAK
RTC Backup Supply Voltage
2.0
3.0
3.6
IBAK
RTC Backup Supply Current
1
IBAKTC
Trickle Charge Current with VBAK=0V
Fast Charge Off (FC = 0)
25
120
Fast Charge On (FC = 1)
200
2500
ILI
Input Leakage Current
±1
ILO
Output Leakage Current
±1
VIH
Input High Voltage
0.7 VDD
VDD + 0.3
VIL
Input Low Voltage
-0.3
0.3 VDD
0.4
VOL1
Output Low Voltage (IOL = 3 mA)
- Applies to SDA and ACS pin
- VDD > VSW
VOL2
Output Low Voltage (IOL = 80 µA)
0.4
- Applies only to ACS pin
- VBAK applied, VDD < VSW
VSW
Battery Switchover Voltage
2.0
2.7
Units
V
Notes
1
2
µA
µA
3
µA
µA
µA
V
µA
µA
µA
µA
µA
V
V
V
4
5
6
7
7
V
V
Notes
1. Full complete operation. RTC operates to lower voltages as specified.
2. SCL toggling between VDD-0.3V and VSS, other inputs VSS or VDD-0.3V. VBC=0. IDD is linear vs frequency.
3. All inputs at VSS or VDD, static. Stop command issued.
4. The VBAK trickle charger automatically regulates the maximum voltage on this pin for capacitor backup applications.
5. VBAK = 3.0V, VDD < VSW, oscillator running.
6. VBAK will source current when the trickle charger is enabled (VBC=1), VDD > VBAK and VDD > VSW.
7. VIN or VOUT = VSS to VDD.
Rev. 0.1
Dec. 2006
Page 17 of 21
FM3135 Integrated RTC/Alarm/FRAM & Embedded Crystal
AC Parameters (TA = -40° C to + 85° C, VDD = 2.7V to 3.6V, CL = 100 pF unless otherwise specified)
Symbol Parameter
Min Max Min Max Min Max
fSCL
SCL Clock Frequency
0
100
0
400
0
1000
tLOW
Clock Low Period
4.7
1.3
0.6
tHIGH
Clock High Period
4.0
0.6
0.4
tAA
SCL Low to SDA Data Out Valid
3
0.9
0.55
tBUF
tHD:STA
tSU:STA
tHD:DAT
tSU:DAT
tR
tF
tSU:STO
tDH
tSP
Bus Free Before New Transmission
Start Condition Hold Time
Start Condition Setup for Repeated
Start
Data In Hold Time
Data In Setup Time
Input Rise Time
Input Fall Time
Stop Condition Setup Time
Data Output Hold (from SCL @ VIL)
Noise Suppression Time Constant
on SCL, SDA
Units
kHz
µs
µs
µs
4.7
4.0
4.7
1.3
0.6
0.6
0.5
0.25
0.25
µs
µs
µs
0
250
0
100
0
100
ns
ns
ns
ns
µs
ns
ns
1000
300
4.0
0
300
300
0.6
0
50
300
100
0.25
0
50
50
Notes
1
1
All SCL specifications as well as start and stop conditions apply to both read and write operations.
Supervisor Timing (TA = -40° C to + 85° C, VDD = 2.7V to 3.6V)
Symbol
Parameter
tVR
VDD Rise Time
tVF
VDD Fall Time
tRPU
Device active after VDD>2.7V
Min
50
100
-
Max
20
Units
µs/V
µs/V
ms
Notes
1,2
1,2
Capacitance (TA = 25° C, f=1.0 MHz, VDD = 3.0V)
Symbol
Parameter
CIO
Input/Output Capacitance
Typ
-
Max
8
Units
pF
Notes
1
Units
Years
Notes
Notes
1
This parameter is characterized but not tested.
2
Slope measured at any point on VDD waveform.
Data Retention (TA = -40° C to + 85° C, VDD = 2.7V to 3.6V)
Parameter
Data Retention
Rev. 0.1
Dec. 2006
Min
10
Page 18 of 21
FM3135 Integrated RTC/Alarm/FRAM & Embedded Crystal
AC Test Conditions
Equivalent AC Test Load Circuit
Input Pulse Levels
Input rise and fall times
Input and output timing levels
3.6V
0.1 VDD to 0.9 VDD
10 ns
0.5 VDD
1100 Ω
Diagram Notes
All start and stop timing parameters apply to both read and write
cycles. Clock specifications are identical for read and write cycles.
Write timing parameters apply to slave address, word address, and
write data bits. Functional relationships are illustrated in the relevant
data sheet sections. These diagrams illustrate the timing parameters
only.
Output
100 pF
Read Bus Timing
tR
`
tF
t HIGH
t SP
t LOW
t SP
SCL
t SU:STA
1/fSCL
tBUF
t HD:DAT
t SU:DAT
SDA
Start
t DH
tAA
Stop Start
Acknowledge
Write Bus Timing
tHD:DAT
SCL
tHD:STA
tSU:STO
tSU:DAT
tAA
SDA
Start
Stop Start
Acknowledge
Power Cycle Timing
VDD
2.7V
t
Can user
access device?
Rev. 0.1
Dec. 2006
yes
no
RPU
yes
Page 19 of 21
FM3135 Integrated RTC/Alarm/FRAM & Embedded Crystal
Mechanical Drawing
20-pin SOIC (JEDEC Standard MS-013d variation AC)
E
h
45°
H
α
Pin 1
L
C
D
Seating Plane
A
B
e
0.10 mm
A1
Refer to JEDEC MS-013 for complete dimensions and notes.
All dimensions in millimeters.
Symbol
A
A1
B
C
D
E
e
H
h
L
α
Dim
mm
mm
mm
mm
mm
mm
mm
in.
mm
mm
mm
Min
2.35
0.10
0.33
0.23
Nom.
Max
2.65
0.30
0.51
0.32
12.8 BSC
7.40
7.60
1.27 BSC
0.050 BSC
10.00
0.25
0.40
0°
10.65
0.75
1.27
8°
SOIC Package Marking Scheme
XXXXXXX-P
LLLLLLL
RICYYWW
Rev. 0.1
Dec. 2006
Legend:
XXXX= part number, P= package type
LLLLLLL= lot code
RIC=Ramtron Int’l Corp, YY=year, WW=work week
Example: FM3135, “Green” SOIC package, Year 2007, Work Week 14
FM3135-G
A70003G
RIC0714
Page 20 of 21
FM3135 Integrated RTC/Alarm/FRAM & Embedded Crystal
Revision History
Revision
0.1
Rev. 0.1
Dec. 2006
Date
12/14/06
Summary
Initial release.
Page 21 of 21