AN97793 Migrating from FM24V02/FM24V01 to CY15B256J/CY15B128J Automotive F-RAM.pdf

AN97793
Migrating from FM24V02/FM24V01 to CY15B256J/CY15B128J Automotive
F-RAM™
Author: Girija Chougala
Associated Part Family: FM24V02, FM24V01, CY15B256J, CY15B128J
Related Documents: For a complete list, click here
AN97793 discusses the key differences that need to be considered when migrating from FM24V02/FM24V01 to
CY15B256J/CY15B128J Automotive F-RAM. FM24V02/FM24V01 is now “Not Recommended for New Designs”; this
application note explains how CY15B256J/CY15B128J is a replacement for FM24V02/FM24V01.
1
Introduction
CY15B256J/CY15B128J, a 256-Kbit/128-Kbit Automotive I2C F-RAM™, is a replacement device for
FM24V02/FM24V01, which is now “Not Recommended For New Designs”. The two devices are identical in terms of
pinout, package composition and dimensions, and read/write functionality. This application note discusses the key
differences between the two devices that need to be considered when migrating from FM24V02/FM24V01 to
CY15B256J/CY15B128J.
2
Device Compatibility
From a hardware point of view, the two devices are identical. From a software point of view, the two devices are
identical except for the power-up to first-access specification (tPU) and Device ID. Refer to Critical Considerations
section for more details.
Table 1 highlights the compatibility chart of FM24V02/FM24V01 and CY15B256J/CY15B128J. For a detailed
comparison, see Table 3.
Table 1. Compatibility Chart
FM24V02/FM24V01 Feature or Spec
www.cypress.com
Is CY15B256J/CY15B128J Compatible?
Package
Yes
Pinout
Yes
Temperature Range
Yes
Operating Voltage
Yes
Operating Current
Yes
Standby Current
Yes
Read / Write Function
Yes
Timing / Frequency
Yes
Data Retention
Yes
Endurance
Yes
Document No. 001-97793 Rev. **
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Migrating from FM24V02/FM24V01 to CY15B256J/CY15B128J Automotive F-RAM™
3
Ordering Part Numbers
Table 2 provides the recommended CY15B256J/CY15B128J ordering part numbers that correspond to the
FM24V02/FM24V01 (Not Recommended for New Designs) ordering part numbers.
Table 2. Recommended Ordering Part Numbers for Migration
FM24V02/FM24V01
Ordering Part Number
CY15B256J/CY15B128J
Status
Ordering Part Number
FM24V02-G
FM24V02-GTR
FM24V01-G
Status
CY15B256J-SXA
CY15B256J-SXAT
Not Recommended
for New Designs
In production
CY15B128J-SXA
FM24V01-GTR
4
Comments
No hardware change required
Software change required
CY15B128J-SXAT
Comparison of FM24V02/FM24V01 and CY15B256J/CY15B128J
Table 3 provides a detailed comparison of the two devices.
Table 3. Detailed Comparison Table
FM24V02/FM24V01
CY15B256J/CY15B128J
Comments
Package Types
-G
-G
Identical “green (RoHS)” packages.
Pinout/ Package Outlines
SOIC-8
SOIC-8
Identical pinout, outline and board
footprint.
Temperature Range
–40 ºC to +85 ºC
–40 ºC to +85 ºC
Identical
Operating Voltage Range
2.0 V to 3.6 V
2.0 V to 3.6 V
Identical
175 µA @ 100 KHz
175 µA @ 100 KHz
400 µA @ 1 MHz
400 µA @ 1 MHz
1000 µA @ 40 MHz
1000 µA @ 40 MHz
Standby Current (max)
150 µA @ 85 ºC
150 µA @ 85 ºC
Identical
Sleep Current (max)
8 µA @ 85 ºC
8 µA @ 85 ºC
Identical
Read / Write Function
2-byte addressing, slave
IDs, device select bits
2-byte addressing, slave
IDs, device select bits
Identical
Clock Frequency
3.4 MHz
3.4 MHz
Identical
10 years (+85 ºC)
10 years (+85 ºC)
38 years (+75 ºC)
38 years (+75 ºC)
151 years (+65 ºC)
151 years (+65 ºC)
Endurance (Write/Read Cycles)
1E+14
1E+14
Identical
Power-Up to First Access (tPU, max)
250 µs
1 ms
CY15B256J/CY15B128J is slower in first
access
004100h
004121h
(FM24V01)
(CY15B128J)
004200h
004221h
(FM24V02)
(CY15B256J)
Active Supply Current (max)
Data Retention
Device ID
www.cypress.com
Document No. 001-97793 Rev. **
Identical
Identical
Different. Refer to Device ID section in
Critical Considerations for more details.
2
Migrating from FM24V02/FM24V01 to CY15B256J/CY15B128J Automotive F-RAM™
FM24V02/FM24V01
Sleep function
The I2C F-RAM enters
Sleep Mode irrespective
of the STOP condition
Output LOW voltage (max)
VOL = 0.2 V @
IOL = 150 μA, VDD ≥ 2.0 V
Output LOW voltage (max)
CY15B256J/CY15B128J
The I2C F-RAM enters
Sleep Mode only if the
STOP condition is issued
Comments
Different. Refer to Sleep Function
section in Critical Considerations for
more details.
Not specified.
This is not an industry
standard specification

VOL = 0.4 V @ IOL = 2 mA,
VDD ≥ 2.7 V
VOL = 0.4 V @ IOL = 3 mA,
VDD ≥ 2.0 V
CY15B256J/CY15B128J has better spec
of higher drive current at lower VDD
Output LOW voltage (max)

VOL = 0.6 V @ IOL = 6 mA,
VDD ≥ 2.0 V
CY15B256J/CY15B128J has additional
spec to meet the NXP I2C specification
Data in hold (tHD:DAT) @ 3.4 MHz
Min: 0 ns
Min: 0 ns
Max: 70 ns
CY15B256J/CY15B128J has additional
max spec to meet the NXP I2C
specification
Input rise time (tR) @ 3.4 MHz
Max: 80 ns
Min: 10 ns
Max: 80 ns
CY15B256J/CY15B128J has additional
min spec to meet the NXP I2C
specification
Input fall time (tF) @ 3.4 MHz
Max: 80 ns
Min: 10 ns
Max: 80 ns
CY15B256J/CY15B128J has additional
min spec to meet the NXP I2C
specification
Input fall time (tF) @ 1.0 MHz
Max: 120 ns
Min: 20 * (VDD / 5.5 V) ns
Max: 120 ns
CY15B256J/CY15B128J has additional
min spec to meet the NXP I2C
specification
ACK output valid time (tVD:ACK)

Max: 130 ns
CY15B256J/CY15B128J has additional
max spec to meet the NXP I2C
specification
Max: 450 ns
CY15B256J/CY15B128J has additional
max spec to meet the NXP I2C
specification
Max: 80 ns
CY15B256J/CY15B128J has additional
max spec to meet the NXP I2C
specification
Min: 20 * (VDD / 5.5 V) ns
Max: 120 ns
CY15B256J/CY15B128J has additional
spec to meet the NXP I2C specification
@ 3.4 MHz
ACK output valid time (tVD:ACK)

@ 1 MHz
Output fall time from VIH min to VIL max
(tOF) @ 3.4 MHz
Output fall time from VIH min to VIL max
(tOF) @ 1 MHz
www.cypress.com


Document No. 001-97793 Rev. **
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Migrating from FM24V02/FM24V01 to CY15B256J/CY15B128J Automotive F-RAM™
5
Critical Considerations
You should consider all the parameter differences mentioned in Table 3 during the migration to
CY15B256J/CY15B128J. This section discusses the critical differences. System designers should also review the
datasheet when migrating to the new part.
5.1
Power-Up to First Access (tPU)
Power-up to first access specification (tPU) is slower in CY15B256J/CY15B128J device compared to
FM24V02/FM24V01. Ensure that the CY15B256J/CY15B128J device is accessed only after 1 ms from power-up.
5.2
Device ID Feature
The CY15B256J/CY15B128J and FM24V02/FM24V01 incorporates a 9-byte read-only Device ID to identify the
product uniquely. The Device ID allows the host to determine the manufacturer, product density, and product revision.
Table 4 provides a Device ID of FM24V02/FM24V01 and CY15B256J/CY15B128J. System software needs to be
updated for Device ID while migrating to the CY15B256J/CY15B128J.
Table 4. Device ID
[Note]
Device ID
FM24V01
CY15B128J
004100h
004121h
FM24V02
CY15B256J
004200h
004221h
Note: Device ID difference highlighted in red color.
5.3
Sleep Function
A low power state called Sleep Mode is supported by FM24V02/FM24V01 and CY15B256J/CY15B128J devices. The
devices will enter in to sleep mode when the Reserved Slave ID 86h is clocked-in as explained in the following
sequence:
1.
2.
3.
4.
5.
6.
7.
8.
9.
The master sends a START command.
The master sends Reserved Slave ID F8h.
The F-RAM (slave device) sends an ACK.
The master sends the I2C-bus slave address of the slave (F-RAM) device it needs to identify. The last bit is a
'Don't care' value (R/W bit).
The F-RAM sends an ACK. Only one device whose I2C-bus slave address matches with the address byte sent
by master must acknowledge it.
The master sends a Re-START command.
The master sends Reserved Slave ID 86h.
The F-RAM sends an ACK.
The master sends STOP and the slave device enters into sleep mode.
However there is a minor difference in the sleep mode entry. Step 9 – Sending STOP condition, is mandatory for
CY15B256J/CY15B128J, whereas it is an optional step for FM24V02/FM24V01.
FM24V02/FM24V01 generates an unintended STOP during sleep mode entry. Refer to Errata section of
FM24V02/FM24V01 datasheet for more details. The Errata is not applicable for CY15B256J/CY15B128J.
www.cypress.com
Document No. 001-97793 Rev. **
4
Migrating from FM24V02/FM24V01 to CY15B256J/CY15B128J Automotive F-RAM™
6
Summary
AN97793 discussed the differences between FM24V02/FM24V01 and CY15B256J/CY15B128J that need to be
considered during migration to the CY15B256J/CY15B128J.
7
Related Documents
Datasheets


CY15B256J: 256-Kbit (32K × 8) Automotive Serial (I2C) F-RAM
CY15B128J: 128-Kbit (16K × 8) Automotive Serial (I2C) F-RAM
www.cypress.com
Document No. 001-97793 Rev. **
5
Migrating from FM24V02/FM24V01 to CY15B256J/CY15B128J Automotive F-RAM™
Document History
Document Title: AN97793 - Migrating from FM24V02/FM24V01 to CY15B256J/CY15B128J Automotive F-RAM™
Document Number: 001-97793
Revision
**
ECN
4800997
www.cypress.com
Orig. of Change
GVCH
Submission Date
06/17/2015
Description of Change
New application note
Document No. 001-97793 Rev. **
6
Migrating from FM24V02/FM24V01 to CY15B256J/CY15B128J Automotive F-RAM™
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Document No. 001-97793 Rev. **
7