FM25V20
2Mb Serial 3V F-RAM Memory
Features
2M bit Ferroelectric Nonvolatile RAM
Organized as 256K x 8 bits
High Endurance 100 Trillion (1014) Read/Writes
10 Year Data Retention
NoDelay™ Writes
Advanced High-Reliability Ferroelectric Process
Very Fast Serial Peripheral Interface - SPI
Up to 40 MHz Frequency
Direct Hardware Replacement for Serial Flash
SPI Mode 0 & 3 (CPOL, CPHA=0,0 & 1,1)
Write Protection Scheme
Hardware Protection
Software Protection
Description
The FM25V20 is a 2-megabit nonvolatile memory
employing an advanced ferroelectric process. A
ferroelectric random access memory or F-RAM is
nonvolatile and performs reads and writes like a
RAM. It provides reliable data retention for 10 years
while eliminating the complexities, overhead, and
system level reliability problems caused by Serial
Flash and other nonvolatile memories.
Device ID
Device ID reads out Manufacturer ID & Part ID
Low Voltage, Low Power
Low Voltage Operation 2.0V – 3.6V
100 A Standby Current (typ.)
3 A Sleep Mode Current (typ.)
Industry Standard Configurations
Industrial Temperature -40C to +85C
8-pin “Green”/RoHS EIAJ SOIC Package
8-pin “Green”/RoHS TDFN Package
8-pin “Green”/POHS PDIP Package
Device ID that allows the host to determine the
manufacturer, product density, and product revision.
The device is guaranteed over an industrial
temperature range of -40°C to +85°C.
Pin Configuration
Top View
Unlike Serial Flash, the FM25V20 performs write
operations at bus speed. No write delays are incurred.
Data is written to the memory array immediately
after it has been transferred to the device. The next
bus cycle may commence without the need for data
polling. The product offers very high write
endurance, orders of magnitude more endurance than
Serial Flash. Also, F-RAM exhibits lower power
consumption than Serial Flash.
These capabilities make the FM25V20 ideal for
nonvolatile memory applications requiring frequent
or rapid writes or low power operation. Examples
range from data collection, where the number of
write cycles may be critical, to demanding controls
where the long write time of Serial Flash can cause
data loss.
The FM25V20 provides substantial benefits to users
of Serial Flash as a hardware drop-in replacement.
The device uses the high-speed SPI bus, which
enhances the high-speed write capability of F-RAM
technology. The device incorporates a read-only
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
August 2012
/S
1
8
VDD
Q
2
7
/HOLD
/W
3
6
C
VSS
4
5
D
S
1
8
VDD
Q
2
7
HOLD
W
3
6
C
VSS
4
5
D
Pin Name
Function
/S
/W
/HOLD
C
D
Q
VDD
VSS
Chip Select
Write Protect
Hold
Serial Clock
Serial Data Input
Serial Data Output
Supply Voltage
Ground
Ramtron International Corporation
1850 Ramtron Drive, Colorado Springs, CO 80921
(800) 545-FRAM, (719) 481-7000
http://www.ramtron.com
Page 1 of 17
FM25V20 – 2Mb SPI F-RAM
W
S
Instruction Decode
Clock Generator
Control Logic
Write Protect
HOLD
C
32K x 64
FRAM Array
Instruction Register
Address Register
Counter
D
18
8
Data I/O Register
Q
3
Nonvolatile Status
Register
Figure 1. Block Diagram
Pin Descriptions
Pin Name
/S
I/O
Input
C
Input
/HOLD
Input
/W
Input
D
Input
Q
Output
VDD
VSS
Supply
Supply
Rev. 3.0
August 2012
Description
Chip Select: This active-low input activates the device. When high, the device enters
low-power standby mode, ignores other inputs, and all outputs are tri-stated. When
low, the device internally activates the C signal. A falling edge on /S must occur prior
to every op-code.
Serial Clock: All I/O activity is synchronized to the serial clock. Inputs are latched on
the rising edge and outputs occur on the falling edge. Since the device is static, the
clock frequency may be any value between 0 and 40 MHz and may be interrupted at
any time.
Hold: The /HOLD pin is used when the host CPU must interrupt a memory operation
for another task. When /HOLD is low, the current operation is suspended. The device
ignores any transition on C or /S. All transitions on /HOLD must occur while C is low.
If it is not used, the /HOLD pin should be tied to VDD.
Write Protect: This active-low pin prevents write operations to the Status Register
only. A complete explanation of write protection is provided on pages 6 and 7. If it is
not used, the /W pin should be tied to VDD.
Serial Input: All data is input to the device on this pin. The pin is sampled on the
rising edge of C and is ignored at other times. It should always be driven to a valid
logic level to meet IDD specifications.
* D may be connected to Q for a single pin data interface.
Serial Output: This is the data output pin. It is driven during a read and remains tristated at all other times including when /HOLD is low. Data transitions are driven on
the falling edge of the serial clock.
* Q may be connected to D for a single pin data interface.
Power Supply
Ground
Page 2 of 17
FM25V20 – 2Mb SPI F-RAM
Overview
The FM25V20 is a serial F-RAM memory. The
memory array is logically organized as 262,144 x 8
and is accessed using an industry standard Serial
Peripheral Interface or SPI bus. Functional operation
of the F-RAM is similar to Serial Flash. The major
differences between the FM25V20 and a Serial Flash
with the same pinout are the F-RAM’s superior write
performance, very high endurance, and lower power
consumption.
Memory Architecture
When accessing the FM25V20, the user addresses
256K locations of 8 data bits each. These data bits are
shifted serially. The addresses are accessed using the
SPI protocol, which includes a chip select (to permit
multiple devices on the bus), an op-code, and a threebyte address. The complete address of 18-bits
specifies each byte address uniquely.
Most functions of the FM25V20 either are controlled
by the SPI interface or are handled automatically by
on-board circuitry. The access time for memory
operation is essentially zero, beyond the time needed
for the serial protocol. That is, the memory is read or
written at the speed of the SPI bus. Unlike Serial
Flash, it is not necessary to poll the device for a ready
condition since writes occur at bus speed. So, by the
time a new bus transaction can be shifted into the
device, a write operation will be complete. This is
explained in more detail in the interface section.
Users expect several obvious system benefits from
the FM25V20 due to its fast write cycle and high
endurance as compared to Serial Flash. In addition
there are less obvious benefits as well. For example
in a high noise environment, the fast-write operation
is less susceptible to corruption than Serial Flash
since it is completed quickly. By contrast, Serial
Flash requiring milliseconds to write is vulnerable to
noise during much of the cycle.
Serial Peripheral Interface – SPI Bus
The FM25V20 employs a Serial Peripheral Interface
(SPI) bus. It is specified to operate at speeds up to
40MHz. This high-speed serial bus provides high
performance serial communication to a host
microcontroller. Many common microcontrollers
have hardware SPI ports allowing a direct interface.
It is quite simple to emulate the port using ordinary
port pins for microcontrollers that do not. The
FM25V20 operates in SPI Mode 0 and 3.
Protocol Overview
The SPI interface is a synchronous serial interface
using clock and data pins. It is intended to support
multiple devices on the bus. Each device is activated
using a chip select. Once chip select is activated by
the bus master, the FM25V20 will begin monitoring
the clock and data lines. The relationship between the
falling edge of /S, the clock and data is dictated by
the SPI mode. The device will make a determination
of the SPI mode on the falling edge of each chip
select. While there are four such modes, the
FM25V20 supports only modes 0 and 3. Figure 2
shows the required signal relationships for modes 0
and 3. For both modes, data is clocked into the
FM25V20 on the rising edge of C and data is
expected on the first rising edge after /S goes active.
If the clock starts from a high state, it will fall prior to
the first data transfer in order to create the first rising
edge.
The SPI protocol is controlled by op-codes. These
op-codes specify the commands to the device. After
/S is activated the first byte transferred from the bus
master is the op-code. Following the op-code, any
addresses and data are then transferred.
Certain op-codes are commands with no subsequent
data transfer. The /S must go inactive after an
operation is complete and before a new op-code can
be issued. There is one valid op-code only per active
chip select.
SPI Mode 0: CPOL=0, CPHA=0
S
C
D
7
6
5
4
3
2
1
MSB
0
LSB
SPI Mode 3: CPOL=1, CPHA=1
S
C
D
7
MSB
6
5
4
3
2
1
0
LSB
Figure 2. SPI Modes 0 & 3
Rev. 3.0
August 2012
Page 3 of 17
FM25V20 – 2Mb SPI F-RAM
System Hookup
The SPI interface uses a total of four pins: clock,
data-in, data-out, and chip select. A typical system
configuration uses one or more FM25V20 devices
with a microcontroller that has a dedicated SPI port,
as Figure 3 illustrates. Note that the clock, data-in,
and data-out pins are common among all devices.
The Chip Select and Hold pins must be driven
separately for each FM25V20 device.
For a microcontroller that has no dedicated SPI bus, a
general purpose port may be used. To reduce
hardware resources on the controller, it is possible to
connect the two data pins together and tie off the
Hold pin. Figure 4 shows a configuration that uses
only three pins.
SCK
MOSI
MISO
Q
SPI
Microcontroller
D
C
Q
D
C
FM25V20
FM25V20
S
S
HOLD
HOLD
SS1
SS2
HOLD1
HOLD2
MOSI : Master Out Slave In
MISO : Master In Slave Out
SS : Slave Select
Figure 3. 4Mbit (512KB) System Configuration with SPI port
P1.0
P1.1
Q
Microcontroller
D
C
FM25V20
S
HOLD
VDD
P1.2
Figure 4. System Configuration without SPI port
Rev. 3.0
August 2012
Page 4 of 17
FM25V20 – 2Mb SPI F-RAM
Power Up to First Access
The FM25V20 is not accessible for a period of time
(tPU) after power up. Users must comply with the
timing parameter tPU, which is the minimum time
from VDD (min) to the first /S low.
Data Transfer
All data transfers to and from the FM25V20 occur in
8-bit groups. They are synchronized to the clock
signal (C), and they transfer most significant bit
(MSB) first. Serial inputs are registered on the rising
edge of C. Outputs are driven from the falling edge of
clock C.
Command Structure
There are nine commands called op-codes that can be
issued by the bus master to the FM25V20. They are
listed in the table below. These op-codes control the
functions performed by the memory. They can be
divided into three categories. First, there are
commands that have no subsequent operations. They
perform a single function, such as to enable a write
operation. Second are commands followed by one
byte, either in or out. They operate on the Status
Register. The third group includes commands for
memory transactions followed by address and one or
more bytes of data.
Table 1. Op-code Commands
Name
Description
Set Write Enable Latch
WREN
Write Disable
WRDI
Read Status Register
RDSR
Write Status Register
WRSR
Read Memory Data
READ
FSTRD Fast Read Memory Data
WRITE Write Memory Data
Enter Sleep Mode
SLEEP
Read Device ID
RDID
without another WREN command. Figure 5 below
illustrates the WREN command bus configuration.
S
0
1
2
3
4
5
6
7
0
0
0
0
0
1
1
0
C
D
Hi-Z
Q
Figure 5. WREN Bus Configuration
WRDI – Write Disable
The WRDI command disables all write activity by
clearing the Write Enable Latch. The user can verify
that writes are disabled by reading the WEL bit in
the Status Register and verifying that WEL=0.
Figure 6 illustrates the WRDI command bus
configuration.
S
0
1
2
3
4
5
6
7
0
0
0
0
0
1
0
0
C
Op-code
0000
0000
0000
0000
0000
0000
0000
1011
1001
0110b
0100b
0101b
0001b
0011b
1011b
0010b
1001b
1111b
WREN – Set Write Enable Latch
The FM25V20 will power up with writes disabled.
The WREN command must be issued prior to any
write operation. Sending the WREN op-code will
allow the user to issue subsequent op-codes for write
operations. These include writing the Status Register
(WRSR) and writing the memory (WRITE).
D
Q
Hi-Z
Figure 6. WRDI Bus Configuration
RDSR – Read Status Register
The RDSR command allows the bus master to
verify the contents of the Status Register. Reading
Status provides information about the current state
of the write protection features. Following the
RDSR op-code, the FM25V20 will return one byte
with the contents of the Status Register. The Status
Register is described in detail in the section below.
Sending the WREN op-code causes the internal Write
Enable Latch to be set. A flag bit in the Status
Register, called WEL, indicates the state of the latch.
WEL=1 indicates that writes are permitted.
Attempting to write the WEL bit in the Status
Register has no effect on the state of this bit.
Completing any write operation will automatically
clear the write-enable latch and prevent further writes
Rev. 3.0
August 2012
Page 5 of 17
FM25V20 – 2Mb SPI F-RAM
WRSR – Write Status Register
The WRSR command allows the user to select
certain write protection features by writing a byte to
the Status Register. Prior to issuing a WRSR
command, the /W pin must be high or inactive. Prior
to sending the WRSR command, the user must send
a WREN command to enable writes. Note that
executing a WRSR command is a write operation
and therefore clears the Write Enable Latch. The bus
configuration of RDSR and WRSR are shown
below.
S
C
D
Q
Figure 7. RDSR Bus Configuration
S
C
D
Q
Figure 8. WRSR Bus Configuration
Status Register & Write Protection
The write protection features of the FM25V20 are
multi-tiered. Taking the /W pin to a logic low state is
the hardware write-protect function. Status Register
write operations are blocked when /W is low. To
write the memory with /W high, a WREN op-code
must first be issued. Assuming that writes are enabled
using WREN and by /W, writes to memory are
controlled by the Status Register. As described
above, writes to the Status Register are performed
using the WRSR command and subject to the /W pin.
The Status Register is organized as follows.
Table 2. Status Register
Bit
Name
7
WPEN
6
1
5
0
4
0
3
BP1
2
BP0
1
WEL
0
0
Bits 0, 4, 5 are fixed at 0 and bit 6 is fixed at 1, and
none of these bits can be modified. Note that bit 0
(“Ready” in Serial Flash) is unnecessary as the FRAM writes in real-time and is never busy, so it
reads out as a ‘0’. There is an exception to this when
the device is waking up from Sleep Mode, which is
described in the Sleep Mode section. The BP1 and
BP0 control software write protection features. They
are nonvolatile (shaded yellow). The WEL flag
indicates the state of the Write Enable Latch.
Attempting to directly write the WEL bit in the Status
Rev. 3.0
August 2012
Register has no effect on its state. This bit is
internally set and cleared via the WREN and WRDI
commands, respectively.
BP1 and BP0 are memory block write protection bits.
They specify portions of memory that are writeprotected as shown in the following table.
Table 3. Block Memory Write Protection
BP1
BP0 Protected Address Range
0
0
None
0
1
30000h to 3FFFFh (upper ¼)
1
0
20000h to 3FFFFh (upper ½)
1
1
00000h to 3FFFFh (all)
The BP1 and BP0 bits and the Write Enable Latch
are the only mechanisms that protect the memory
from writes. The remaining write protection features
protect inadvertent changes to the block protect bits.
The WPEN bit controls the effect of the hardware /W
pin. When WPEN is low, the /W pin is ignored.
When WPEN is high, the /W pin controls write
access to the Status Register. Thus the Status Register
is write protected if WPEN=1 and /W=0.
This scheme provides a write protection mechanism,
which can prevent software from writing the memory
Page 6 of 17
FM25V20 – 2Mb SPI F-RAM
under any circumstances. This occurs if the BP1 and
BP0 bits are set to 1, the WPEN bit is set to 1, and
the /W pin is low. This occurs because the block
protect bits prevent writing memory and the /W
signal in hardware prevents altering the block protect
Table 4. Write Protection
WEL
WPEN
0
X
1
0
1
1
1
1
/W
X
X
0
1
Protected Blocks
Protected
Protected
Protected
Protected
Memory Operation
The SPI interface, which is capable of a relatively
high clock frequency, highlights the fast write
capability of the F-RAM technology. Unlike Serial
Flash, the FM25V20 can perform sequential writes at
bus speed. No page buffer is needed and any number
of sequential writes may be performed.
Write Operation
All writes to the memory array begin with a WREN
op-code. The next op-code is the WRITE instruction.
This op-code is followed by a three-byte address
value, which specifies the 18-bit address of the first
data byte of the write operation. Subsequent bytes are
data and they are written sequentially. Addresses are
incremented internally as long as the bus master
continues to issue clocks. If the last address of
3FFFFh is reached, the counter will roll over to
00000h. Data is written MSB first. A write operation
is shown in Figure 9.
Unlike Serial Flash, any number of bytes can be
written sequentially and each byte is written to
memory immediately after it is clocked in (after the
8th clock). The rising edge of /S terminates a WRITE
op-code operation. Asserting /W active in the middle
of a write operation will have no effect until the next
falling edge of /S.
Read Operation
After the falling edge of /S, the bus master can issue
a READ op-code. Following this instruction is a
three-byte address value (A17-A0), specifying the
address of the first data byte of the read operation.
After the op-code and address are complete, the D
pin is ignored. The bus master issues 8 clocks, with
Rev. 3.0
August 2012
bits (if WPEN is high). Therefore in this condition,
hardware must be involved in allowing a write
operation. The following table summarizes the write
protection conditions.
Unprotected Blocks
Protected
Unprotected
Unprotected
Unprotected
Status Register
Protected
Unprotected
Protected
Unprotected
one bit read out for each. Addresses are incremented
internally as long as the bus master continues to issue
clocks. If the last address of 3FFFFh is reached, the
counter will roll over to 00000h. Data is read MSB
first. The rising edge of /S terminates a READ opcode operation and tri-states the Q pin. A read
operation is shown in Figure 10.
Fast Read Operation
The FM25V20 supports the FAST READ op-code
(0Bh) that is found on Serial Flash devices. It is
implemented for code compatibility with Serial Flash
devices. Following this instruction is a three-byte
address (A17-A0), specifying the address of the first
data byte of the read operation. A dummy address
byte follows the address. It inserts one byte of read
latency. The D pin is ignored after the op-code, threebyte address, and dummy byte are complete. The bus
master issues 8 clocks, with one bit read out for each.
The Fast Read operation is otherwise the same as an
ordinary READ. If the last address of 3FFFFh is
reached, the counter will roll over to 00000h. Data is
read MSB first. The rising edge of /S terminates a
FAST READ op-code operation and tri-states the Q
pin. A Fast Read operation is shown in Figure 11.
Hold
The FM25V20 device has a /HOLD pin that can be
used to interrupt a serial operation without aborting
it. If the bus master pulls the /HOLD pin low while C
is low, the current operation will pause. Taking the
/HOLD pin high while C is low will resume an
operation. The transitions of /HOLD must occur
while C is low, but the C and /S pins can toggle
during a hold state.
Page 7 of 17
FM25V20 – 2Mb SPI F-RAM
S
0
1
2
3
4
5
6
7
0
1
2
0
0
0
3
4
5
6
7
4
5
6
7
0
1
2
3
4
5
6
7
A3 A2 A1 A0
7
6
Data
5 4
3
2
1
0
C
op-code
D
0
0
0
0
0
18-bit Add ress
0
1
0
0
0
0 A17 A16
MSB
LSB MSB
LSB
Q
Figure 9. Memory Write with 3-Byte Address
S
0
1
2
3
4
5
6
7
0
1
2
0
0
0
3
4
5
6
7
4
5
6
7
0
1
2
7
6
5
0
1
2
6
5
3
4
5
6
7
4
3
2
1
0
3
4
5
6
7
3
2
1
C
18-bit Address
op-code
D
0
0
0
0
0
0
1
1
0
0
0 A17 A16
A3 A2 A1 A0
MSB
LSB
Q
Data
MSB
LSB
Figure 10. Memory Read with 3-Byte Address
S
0
1
2
3
4
5
6
7
0
1
2
0
0
0
3
5
6
7
4
5
6
7
C
op-code
D
0
0
0
0
1
1
1
MSB
Q
Dummy byte
18-bit Address
0
0
A2 A1 A0
LSB
X
X
X
X
Data
MSB
7
4
LSB
0
Figure 11. Fast Read with 3-Byte Address and Dummy Byte
Rev. 3.0
August 2012
Page 8 of 17
FM25V20 – 2Mb SPI F-RAM
Sleep Mode
A low power mode called Sleep Mode is
implemented on the FM25V20 device. The device
will enter this low power state when the SLEEP opcode B9h is clocked-in and a rising edge of /S is
applied. Once in sleep mode, the C and D pins are
ignored and Q will be high-Z, but the device
continues to monitor the /S pin. On the next falling
edge of /S, the device will return to normal operation
within tREC (400 s max.). The Q pin remains in a hiZ state during the wakeup period. The device will not
necessarily respond to an opcode within the wakeup
period. To start the wakeup procedure, the controller
may send a “dummy” read, for example, and wait the
remaining tREC time.
Enter Sleep
Mode
S
C
D
Q
Figure 12. Sleep Mode Entry
Device ID
The FM25V20 device can be interrogated for its manufacturer, product identification, and die revision. The RDID
op-code 9Fh allows the user to read the manufacturer ID and product ID, both of which are read-only bytes. The
JEDEC-assigned manufacturer ID places the Ramtron identifier in bank 7, therefore there are six bytes of the
continuation code 7Fh followed by the single byte C2h. There are two bytes of product ID, which includes a Family
code, a Density code, a Sub code, and Product Revision code.
Table 5. Manufacturer and Product ID
Manufacturer ID
Device ID (1st Byte)
Device ID (2nd Byte)
7
0
0
0
0
0
0
1
6
1
1
1
1
1
1
1
5
1
1
1
1
1
1
0
Bit
4 3
1 1
1 1
1 1
1 1
1 1
1 1
0 0
2
1
1
1
1
1
1
0
1
1
1
1
1
1
1
1
0
1
1
1
1
1
1
0
Hex
7F
7F
7F
7F
7F
7F
C2
Continuation code
Continuation code
Continuation code
Continuation code
Continuation code
Continuation code
JEDEC assigned Ramtron C2h in bank 7
Family
Density
0 0 1 0 0 1 0 1
Sub
Rev.
Rsvd
0 0 0 0 0 0 0 0
Hex
25h
Density: 03h=512K, 04h=1M, 05h=2M, 06h=4M
00h
00h=FM25V20
7Fh
C2h
S
.......
C
D
Q
9Fh
7Fh
…
1
25h
00h
6
Six bytes of continuation code 7Fh
Figure 13. Read Device ID
Rev. 3.0
August 2012
Page 9 of 17
FM25V20 - 2Mb SPI F-RAM
Endurance
The FM25V20 device is capable of being accessed at
least 1014 times, reads or writes. An F-RAM memory
operates with a read and restore mechanism.
Therefore, an endurance cycle is applied on a row
basis for each access (read or write) to the memory
array. The F-RAM architecture is based on an array
of rows and columns. Rows are defined by A17-A3
and column addresses by A2-A0.
See Block
Diagram (pg 2) which shows the array as 32K rows
of 64-bits each. The entire row is internally accessed
once whether a single byte or all eight bytes are read
or written. Each byte in the row is counted only once
in an endurance calculation. The table below shows
endurance calculations for 64-byte repeating loop,
which includes an op-code, a starting address, and a
sequential 64-byte data stream. This causes each byte
to experience one endurance cycle through the loop.
F-RAM read and write endurance is virtually
unlimited even at 40MHz clock rate.
Table 6. Time to Reach 100 Trillion Cycles for Repeating 64-byte Loop
SCK Freq
Endurance
Endurance
Years to Reach
(MHz)
Cycles/sec.
Cycles/year
1014 Cycles
12
43.1
40
73,520
2.32 x 10
10
18,380
5.79 x 1011
172.7
5
9,190
2.90 x 1011
345.4
Rev. 3.0
August 2012
Page 10 of 17
FM25V20 - 2Mb SPI F-RAM
Electrical Specifications
Absolute Maximum Ratings
Symbol
Description
VDD
Power Supply Voltage with respect to VSS
VIN
Voltage on any pin with respect to VSS
TSTG
TLEAD
VESD
Storage Temperature
Lead Temperature (Soldering, 10 seconds)
Electrostatic Discharge Voltage
- Human Body Model (JEDEC Std JESD22-A114-B)
- Charged Device Model (JEDEC Std JESD22-C101-A)
- Machine Model (JEDEC Std JESD22-A115-A)
Package Moisture Sensitivity Level
Ratings
-1.0V to +4.5V
-1.0V to +4.5V
and VIN < VDD+1.0V
-55C to + 125C
260 C
4kV
1.25kV
250V
MSL-1
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 = -40C to + 85C, VDD = 2.0V to 3.6V unless otherwise specified)
Symbol Parameter
Min
Typ
Max
Units
VDD
Power Supply Voltage
2.0
3.3
3.6
V
IDD
Power Supply Operating Current
@ C = 1 MHz
0.13
0.30
mA
@ C = 40 MHz
1.4
3.0
mA
ISB
Standby Current
A
@ TA = 25°C
100
150
A
@ TA = 85°C
250
IZZ
Sleep Mode Current
A
@ TA = 25°C
3
5
A
@ TA = 85°C
8
ILI
Input Leakage Current
A
1
ILO
Output Leakage Current
A
1
VIH
Input High Voltage
0.7 VDD
VDD + 0.3
V
VIL
Input Low Voltage
-0.3
0.3 VDD
V
VOH1
Output High Voltage (IOH = -1 mA, VDD=2.7V)
2.4
V
VOH2
Output High Voltage (IOH = -100 A)
VDD-0.2
V
VOL1
Output Low Voltage (IOL = 2 mA, VDD=2.7V)
0.4
V
VOL2
Output Low Voltage (IOL = 150 A)
0.2
V
Notes
1. C toggling between VDD-0.2V and VSS, other inputs VSS or VDD-0.2V. Q=open.
2. /S=VDD. All inputs VSS or VDD.
3. In Sleep mode and /S=VDD. All inputs VSS or VDD.
4. VSS VIN VDD and VSS VOUT VDD.
Data Retention (TA = -40C to + 85C)
Symbol
Parameter
TDR
Data Retention
Rev. 3.0
August 2012
Min
10
Max
-
Units
Years
Notes
1
2
3
4
4
Notes
Page 11 of 17
FM25V20 – 2Mb SPI F-RAM
AC Parameters (TA = -40C to + 85C, CL = 30pF, unless otherwise specified)
VDD 2.0 to 2.7V
VDD 2.7 to 3.6V
Symbol
Parameter
Min
Max
Min
Max
fCK
C Clock Frequency
0
25
0
40
tCH
Clock High Time
20
11
tCL
Clock Low Time
20
11
tCSU
Chip Select Setup
12
10
tCSH
Chip Select Hold
12
10
tOD
Output Disable Time
20
12
tODV
Output Data Valid Time
18
9
tOH
Output Hold Time
0
0
tD
Deselect Time
60
40
tR
Data In Rise Time
50
50
tF
Data In Fall Time
50
50
tSU
Data Setup Time
8
5
tH
Data Hold Time
8
5
tHS
/HOLD Setup Time
12
10
tHH
/HOLD Hold Time
12
10
tHZ
/HOLD Low to Hi-Z
25
20
tLZ
/HOLD High to Data Active
25
20
Notes
1.
2.
3.
4.
Units
MHz
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
Notes
1
1
3
3
2,4
2,4
3
4
4
tCH + tCL = 1/fCK.
Rise and fall times measured between 10% and 90% of waveform.
Guaranteed by design.
Guaranteed by design for 1MHz fCK.
Capacitance (TA = 25 C, f=1.0 MHz, VDD = 3.3V)
Symbol Parameter
CO
Output Capacitance (Q)
CI
Input Capacitance
Notes
1. Guaranteed by design.
AC Test Conditions
Input Pulse Levels
Input rise and fall times
Input and output timing levels
Output Load Capacitance
Min
-
Max
8
6
Units
pF
pF
Notes
1
1
10% and 90% of VDD
3 ns
50% of VDD
30 pF
Serial Data Bus Timing
tD
S
tCSU
C
tSU
tF
1/tCK
tR
tCL
tCH
tCSH
tH
D
tODV
tOH
tOD
Q
/HOLD Timing
Rev. 3.0
August 2012
Page 12 of 17
FM25V20 – 2Mb SPI F-RAM
tHS
S
tHH
C
tHH
tHS
HOLD
Q
tHZ
tLZ
Power Cycle Timing
VDD
VDD min.
tVR
tVF
tPU
tPD
S
Power Cycle & Sleep Timing (TA = -40 C to + 85 C, VDD = 2.0V to 3.6V, unless otherwise specified)
Symbol Parameter
Min
Max
Units
Notes
tVR
VDD Rise Time
50
s/V
1
tVF
VDD Fall Time
100
s/V
1
tPU
Power Up (VDD min) to First Access (/S low)
1
ms
tPD
Last Access (/S high) to Power Down (VDD min)
0
s
2
tREC
Recovery Time from Sleep Mode
450
s
Notes
1. Slope measured at any point on VDD waveform.
2. Guaranteed by design.
Rev. 3.0
August 2012
Page 13 of 17
FM25V20 – 2Mb SPI F-RAM
Mechanical Drawing
8-pin TDFN* (5.0 mm x 6.0 mm body, 1.27 mm pad pitch)
Exposed metal pad
should be left floating.
6.0 BSC
5.0 BSC
Pin 1 ID
Pin 1
0.60 ±0.05
3.81 REF
0.0 - 0.05
0.75 ±0.05
0.20 REF.
Recommended PCB Footprint
1.27
0.40 ±0.05
1.4
6.80
Silkscreen
Pin 1
1.27
0.60
Note: All dimensions in millimeters. This package is footprint compatible with the 8-pin SOIC.
The exposed pad should be left floating.
TDFN Package Marking Scheme for Body Size 5.0mm x 6.0mm
RGXXXXT
LLLL
YYWW
Legend:
R=Ramtron, G=”green” TDFN package
XXXX=base part number, T=temperature (blank=ind., C=comm.)
LLLL= lot code
YY=year, WW=work week
Example: “Green” TDFN package, FM25V20, Lot 0012, Year 2010, Work Week 29
RG5V20
0012
1029
Rev. 3.0
August 2012
Page 14 of 17
FM25V20 – 2Mb SPI F-RAM
Mechanical Drawing
8-pin DIP* JEDEC MS-001
0.280 max
0.240 min
Index
Area
0.325 max
0.300 min
0.400 max
0.355 min
0.195 max 0.210
0.115 min max
0.015 min
0.005 min
0.100
BSC
0.022 max
0.014 min
0.300 nom
0.430 max
Refer to JEDEC MS-001 for complete dimensions and notes.
Controlling dimensions in inches.
PDIP Package Marking Scheme
XXXXX-PT
RLLLLLLL
RICYYWW
Legend:
XXXXX= part number, P=Package (P=PDIP “Green”),
T=Temp. Range (C=commercial, =industrial)
R=rev code, LLLLLLL= lot code
RIC=Ramtron Int’l Corp, YY=year, WW=work week
Example: FM25H20, “Green”/RoHS PDIP package,
Rev. A, Lot 0448727, Year 2011, Work Week 03
25H20-P
A0448727
RIC1103
Rev. 3.0
August 2012
Page 15 of 17
FM25V20 – 2Mb SPI F-RAM
8-pin EIAJ SOIC
Recommended PCB Footprint
9.30
5.28 ±0.10
5.00
8.00 ±0.25
2.15
0.65
1.27
Pin 1
5.23 ±0.10
1.27
0.36
0.50
1.78
2.00
0.05
0.25
0.19
0.25
0.10 mm
0- 8
0.51
0.76
All dimensions in millimeters.
EIAJ SOIC Package Marking Scheme
XXXXXXX-PT
RLLLLLLL
RIC YYWW
Legend:
XXXXXX= part number, P=package (G=”Green”), T=temp (blank=ind., C=comm.)
R=rev code, LLLLLLL= lot code
RIC=Ramtron Int’l Corp, YY=year, WW=work week
Example: FM25V20, “Green”/RoHS EIAJ SOIC package,
Rev A, Lot 0448727, Year 2010, Work Week 29
FM25V20-G
A0448727
RIC 1029
Rev. 3.0
August 2012
Page 16 of 17
FM25V20 – 2Mb SPI F-RAM
Revision History
Revision
1.0
1.1
1.2
2.0
3.0
Date
6/15/2010
8/8/2011
11/21/2011
12/20/2011
08/13/2012
Summary
Initial release.
Removed S/N options.
Added ESD ratings.
Changed to Pre-Production status. Changed tPU and tREC specs.
Changed to Production status. Parameters tOD, tOH, tR, tF, tHH, tHZ & tLZ
changed to “Guaranteed by Design”. Added PDIP package. Note: Packages
marked * are under package vendor re-qualification.
Ordering Information
Part Number
Features
FM25V20-G
FM25V20-DG
FM25V20-PG
FM25V20-GTR
FM25V20-DGTR
Rev. 3.0
August 2012
Device ID
Device ID
Device ID
Device ID
Operating
Voltage
2.0-3.6V
2.0-3.6V
2.0-3.6V
2.0-3.6V
Operating
Temp.
-40C to +85C
-40C to +85C
-40C to +85C
-40C to +85C
Device ID
2.0-3.6V
-40C to +85C
Package
8-pin “Green”/RoHS EIAJ
8-pin “Green”/RoHS TDFN*
8-pin “Green”/RoHS PDIP*
8-pin “Green”/RoHS EIAJ,
Tape & Reel
8-pin “Green”/RoHS TDFN,
Tape & Reel
Page 17 of 17
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