Sample &
Buy
Product
Folder
Support &
Community
Tools &
Software
Technical
Documents
bq2026
SLUS938A – DECEMBER 2011 – REVISED OCTOBER 2014
1.5K-Bit Serial EPROM with SDQ Interface
1 Features
3 Description
•
The bq2026 is a 1.5K-bit serial EPROM containing a
factory-programmed, unique 48-bit identification
number, 8-bit family code, and a 64-bit status
register.
1
•
•
•
•
•
•
1536 Bits of One-Time Programmable (OTP)
EPROM For Storage Of User-Programmable
Configuration Data
Factory-Programmed Unique 64-Bit Identification
Number
Single-Wire Interface to Reduce Circuit Board
Routing
Synchronous Communication Reduces Host
Interrupt Overhead
6KV IEC 61000-4-2 ESD Compliance on Data Pin
No Standby Power Required
Available in a 3-Pin SOT-23 and TO-92 Packages
The bq2026 SDQ™ interface requires only a single
connection and a ground return. The SDQ pin is also
the sole power source for the bq2026.
The small surface-mount package options saves
printed-circuit-board space, while the low cost makes
it ideal for applications such as battery-pack
configuration parameters, record maintenance, asset
tracking, product-revision status, and access-code
security.
Device Information(1)
2 Applications
•
•
•
•
PART NUMBER
Security Encoding
Inventory Tracking
Product-Revision Maintenance
Battery-Pack Identification
bq2026
PACKAGE
BODY SIZE (NOM)
SOT-23 (3)
4.30 mm × 4.30 mm
TO-92 (3)
2.92 mm × 1.30 mm
(1) For all available packages, see the package option addendum
at the end of the datasheet.
Block Diagram
DBZ Package
(Top View)
SDQ
SDQ Communications
Controller and CRC
Generation Circuit
Internal
Bus
ID ROM
(64 bits)
RAM
Buffer
(1 byte)
EPROM
Status
(64 bits)
1
VSS
2
3
EPROM
Memory
(1536 bits)
VSS
SDQ
VSS
VSS
LP Package
(BottomView)
1
2
3
VSS
SDQ
VSS
NOTE: Pin 3 for LP package can be ground or left unconnected.
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.
bq2026
SLUS938A – DECEMBER 2011 – REVISED OCTOBER 2014
www.ti.com
Table of Contents
1
2
3
4
5
6
Features ..................................................................
Applications ...........................................................
Description .............................................................
Revision History.....................................................
Pin Configuration and Functions .........................
Specifications.........................................................
1
1
1
2
3
3
6.1
6.2
6.3
6.4
3
3
4
4
Absolute Maximum Ratings ......................................
Handling Ratings.......................................................
Electrical Characteristics: DC ...................................
Switching Characteristcs: AC....................................
7
Detailed Description .............................................. 5
7.1
7.2
7.3
7.4
8
Overview ...................................................................
Functional Block Diagram .........................................
Feature Description...................................................
Device Functional Modes..........................................
5
5
5
6
Device and Documentation Support.................. 15
8.1 Trademarks ............................................................. 15
8.2 Electrostatic Discharge Caution .............................. 15
8.3 Glossary .................................................................. 15
9
Mechanical, Packaging, and Orderable
Information ........................................................... 15
4 Revision History
Changes from Original (April 2013) to Revision A
Page
•
Changed document format to latest data sheet standards .................................................................................................... 1
•
Added Handling Rating table, Feature Description, Device Functional Modes, Device and Documentation Support,
and Mechanical, Packaging, and Orderable Information sections ......................................................................................... 1
•
Added note to front page diagram ......................................................................................................................................... 1
•
Changed pin 3 (VSS) description for LP package.................................................................................................................. 3
2
Submit Documentation Feedback
Copyright © 2011–2014, Texas Instruments Incorporated
Product Folder Links: bq2026
bq2026
www.ti.com
SLUS938A – DECEMBER 2011 – REVISED OCTOBER 2014
5 Pin Configuration and Functions
DBZ Package
SOT-23-3
(Top View)
SDQ
1
VSS
3
VSS
2
LP Package
TO-92-3
(Top View)
1
2
3
VSS
SDQ
VSS
Pin Functions
PIN
NAME
I/O
DESCRIPTION
DBZ
LP
SDQ
1
2
I/O
Data
VSS
2, 3
1
—
Ground
VSS
—
3
—
Can be ground or left unconnected
6 Specifications
6.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted)
(1)
DC voltage applied to VPU See Figure 1
MIN
MAX
–0.3
12.5
V
5
mA
6
kV
70
°C
Low-level output current, IOL
ESD IEC 61000-4-2 Air discharge
SDQ to VSS, VSS to SDQ
Operating free-air temperature range, TA
(1)
–20
UNIT
Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings
only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended
Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
6.2 Handling Ratings
MIN
MAX
UNIT
Storage temperature range
–55
125
°C
Copyright © 2011–2014, Texas Instruments Incorporated
Submit Documentation Feedback
Tstg
Product Folder Links: bq2026
3
bq2026
SLUS938A – DECEMBER 2011 – REVISED OCTOBER 2014
www.ti.com
6.3 Electrical Characteristics: DC
At TA = –20°C to 70°C; VPU(min) = 2.65 VDC to 5.5 VDC, all voltages relative to VSS.
PARAMETER
ISDQ
TEST CONDITION
Supply current
MIN
TYP
MAX
UNIT
VPU = 5.5 V
20
μA
Logic 0, VPU = 5.5 V, IOL = 4 mA, SDQ pin
0.4
V
Logic 0, VPU = 2.65 V, IOL = 2 mA
0.4
V
5.5
V
VOL
Low-level output voltage
VOH
High-level output voltage
Logic 1
IOL
Low-level output current (sink)
VOL = 0.4 V, SDQ pin
VIL
Low-level input voltage
Logic 0
VIH
High-level input voltage
Logic 1
VPP
Programming voltage
Ilkg
Input leakage
1.4
µA
CI
Input capacitance
1.2
nF
VPU
4
0.8
2.2
mA
V
V
11.5
12
V
6.4 Switching Characteristcs: AC
TA = –20°C to 70°C; VPU(min) = 2.65 VDC to 5.5 VDC, all voltages relative to VSS
PARAMETER
tc
Bit cycle time (1)
tWSTRB
Write start cycle (1)
tWDSU
Write data setup
tWDH
Write data hold (1) (2)
trec
Recovery time (1)
tRSTRB
Read start cycle
tODD
Output data delay
tODHO
Output data hold
tRST
Reset time (1)
tPPD
Presence pulse delay
tPP
Presence pulse (1)
tEPROG
EPROM programming time
tPSU
tPREC
tPRE
Program rising-edge time
tPFE
Program falling-edge time
TEST CONDITION
(1)
4
MAX
UNIT
60
TYP
120
μs
1
15
μs
tWSTRB
15
μs
60
tc
μs
μs
1
(1)
(1)
(1)
1
13
μs
tRSTRB
13
μs
17
60
μs
μs
480
(1)
15
64
μs
60
240
μs
480
μs
Program setup time
5
μs
Program recovery time
5
tRSTREC
(1)
(2)
MIN
480
μs
5
μs
5
μs
μs
5-kΩ series resistor between SDQ pin and VPU. (See Figure 1)
tWDH must be less than tc to account for recovery.
Submit Documentation Feedback
Copyright © 2011–2014, Texas Instruments Incorporated
Product Folder Links: bq2026
bq2026
www.ti.com
SLUS938A – DECEMBER 2011 – REVISED OCTOBER 2014
7 Detailed Description
7.1 Overview
The block diagram shows the relationships among the major control and memory sections of the bq2026. The
bq2026 has three main data components: a 64-bit factory-programmed ROM, including 8-bit family code, 48-bit
identification number and 8-bit CRC value, 1536-bit EPROM, and EPROM Status bytes. Power for read and write
operations is derived from the SDQ pin. An internal capacitor stores energy while the signal line is high, and
releases energy during the low times of the SDQ pin until the pin returns high to replenish the charge on the
capacitor.
7.2 Functional Block Diagram
SDQ
SDQ Communications
Controller and CRC
Generation Circuit
ID ROM
(64 bits)
Internal
Bus
EPROM
Memory
(1536 bits)
VSS
EPROM
Status
(64 bits)
RAM
Buffer
(1 byte)
VSS
7.3 Feature Description
7.3.1 EPROM
Table 1 is a memory map of the 1536-bit EPROM section of the bq2026, configured as six pages of 32 bytes
each. The 1-byte RAM buffer is an additional register used when programming the memory. Data are first written
to the RAM buffer and then verified by reading a 16-bit CRC from the bq2026 that confirms proper receipt of the
data. If the buffer contents are correct, a programming pulse is issued and a 1-byte segment of data is written
into the selected address in memory. This process ensures data integrity when programming the memory. The
details for reading and programming the 1536-bit EPROM portion of the bq2026 are in the Memory and Status
Function Commands section of this data sheet.
Table 1. 1536-Bit EPROM Data Memory Map
ADDRESS (HEX)
PAGE
00A0-00BF
Page 5
0080-009F
Page 4
0060-007F
Page 3
0040-005F
Page 2
0020-003F
Page 1
0000-001F
Page 0
7.3.2 EPROM Status Memory
In addition to the programmable 1536-bits of memory are eight bytes of status information, the first seven bytes
are available to the user, contained in the EPROM status memory. The status memory is accessible with
separate commands. The status bytes are EPROM and are read or programmed to indicate various conditions to
the software interrogating the bq2026. These general-purpose bytes can be used by the customer to store
various information.
Table 2. EPROM Status Bytes
ADDRESS (HEX)
100h-107h
PAGE
General-purpose OTP status memory
Submit Documentation Feedback
Copyright © 2011–2014, Texas Instruments Incorporated
Product Folder Links: bq2026
5
bq2026
SLUS938A – DECEMBER 2011 – REVISED OCTOBER 2014
www.ti.com
7.3.3 Error Checking
Implement error checking by comparing the 16-bit CRC values transmitted by the bq2026. If the two CRC values
match, the transmission is error-free. Details are found in the CRC Generation section.
7.4 Device Functional Modes
7.4.1 Customizing the bq2026
The 64-bit ID identifies each bq2026 device. The 48-bit serial number is unique and programmed by Texas
Instruments. The default 8-bit family code is 09h; however, a different value can be reserved on an individual
customer basis. Contact your Texas Instruments sales representative for more information.
7.4.2 Bus Termination
Because the drive output of the bq2026 is an open-drain, N-channel MOSFET, the host must provide a source
current or a 5-kΩ external pullup, as shown in the typical application circuit in Figure 1.
VPU
bq2026
SDQ
SDQI
1
Communications
Controller
CPU
SDQO
VSS
3
VSS
2
HOST
Figure 1. Bus Termination Example for SOT-23 Package
7.4.3 Serial Communication
A host reads, programs, or checks the status of the bq2026 through the hierarchical command structure of the
SDQ interface. Figure 2 shows that the host must first issue a ROM command before the EPROM memory or
status can be read or modified.
Initialization
ROM Command Sequence
Memory and Status Command Sequence
Figure 2. General Command Sequence
7.4.4 Initialization
Initialization consists of two pulses, the reset and the presence pulses. The host generates the reset pulse, while
the bq2026 responds with the presence pulse. The host resets the bq2026 by driving the DATA bus low for at
least 480 μs. For more details, see the Reset and Presence Pulse section.
6
Submit Documentation Feedback
Copyright © 2011–2014, Texas Instruments Incorporated
Product Folder Links: bq2026
bq2026
www.ti.com
SLUS938A – DECEMBER 2011 – REVISED OCTOBER 2014
7.4.5 ROM Commands
7.4.5.1 Read ROM
The Read ROM command sequence is the fastest sequence that allows the host to read the 8-bit family code
and 48-bit identification number. The Read ROM sequence starts with the host generating the reset pulse of at
least 480 μs. The bq2026 responds with a presence pulse. Next, the host continues by issuing the Read ROM
command, 33h, and then reads the ROM and CRC byte using the read signaling (see the Write and Read
sections) during the data frame.
Reset
and
Presence
Signals
1
1
Read ROM (33h)
0
0
1
1
Family Code and Identification
Number (7 BYTES)
0
0
CRC (1 BYTE)
Figure 3. Read ROM Sequence
7.4.5.2 Match ROM
The Match ROM command, 55h, is used by the host to select a specific SDQ device when the family code and
identification number is known. The host issues the Match ROM command followed by the family code, ROM
number, and the CRC byte. The device that matches the 64-bit ROM sequence is selected and available to
perform subsequent memory and status function commands.
Reset
and
Presence
Signals
1
0
Match ROM (55h)
1
0
1
0
1
Family Code and Identification
Number (7 BYTES)
0
CRC (1 BYTE)
Figure 4. Match ROM Sequence
7.4.5.3 Skip ROM
This Skip ROM command, CCh, allows the host to access the memory and status functions without issuing the
64-bit ROM code sequence. The Skip ROM command is directly followed by a memory or status functions
command.
Reset
and
Presence
Signals
Skip ROM (CCh)
0
1
0
1
0
1
0
1
Figure 5. Skip ROM Sequence
Submit Documentation Feedback
Copyright © 2011–2014, Texas Instruments Incorporated
Product Folder Links: bq2026
7
bq2026
SLUS938A – DECEMBER 2011 – REVISED OCTOBER 2014
www.ti.com
7.4.6 Memory and Status Function Commands
Four memory and status function commands allow read and modification of the 1536-bit EPROM data memory
or the 7-byte EPROM status memory. There is a Read Memory and Field CRC command, plus the Write
Memory, Read Status, and Write Status commands. The bq2026 responds to memory and status function
commands only after a device is selected by a ROM command.
7.4.7 Read Memory and Field CRC
To read the memory, the ROM command is followed by the Read Memory command, F0h, followed by the
address low byte and then the address high byte.
The host then issues read time slots and receives data from the bq2026, starting at the initial address and
continuing until the end of the 1536-bit data field is reached, or until a reset pulse is issued. If reading occurs
through the end of memory space, the host may issue sixteen additional read time slots and the bq2026
responds with a 16-bit CRC of all data bytes read from the initial starting byte through the last byte of memory.
After the CRC is received by the host, any subsequent read time slots appears as logical 1s until a reset pulse is
issued. Any reads ended by a reset pulse prior to reaching the end of memory do not have the 16-bit CRC
available.
Initialization and ROM
Command Sequence
Read Memory Command
F0h
Address Low
Byte
A0
(1)
Address High
Byte
A7 A8
Read and
Verify 16-bit
CRC
Read EPROM Memory Until
End of EPROM Memory
A15
Individual bytes of address and data are transmitted LSB first.
Figure 6. Read Memory and Field CRC
7.4.8 Read Status
The Read Status command is used to read data from the EPROM status data field. After issuing a ROM
command, the host issues the Read Status command, AAh, followed by the address low byte and then the
address high byte.
NOTE
An 16-bit CRC of the command byte and address bytes is computed by the bq2026 and
read back by the host to confirm that the correct command word and starting address
were received.
If the CRC read by the host is incorrect, a reset pulse must be issued and the entire sequence must be repeated.
If the CRC received by the host is correct, the host issues read time slots and receives data from the bq2026
starting at the supplied address and continuing until the end of the EPROM Status data field is reached. At that
point, the host receives a 16-bit CRC that is the result of shifting into the CRC generator all of the data bytes
from the initial starting byte through the final byte.
This feature is provided because the EPROM status information may change over time making it impossible to
program the data once and include an accompanying CRC that is always valid. Therefore, the Read Status
command supplies a 16-bit CRC that is based on (and always is consistent with) the current data stored in the
EPROM status data field.
After the 16-bit CRC is read, the host receives logical 1s from the bq2026 until a reset pulse is issued. The Read
Status command sequence can be ended at any point by issuing a reset pulse.
Initialization and ROM
CommandSequence
Read Memory Command
AAh
Address Low
Byte
A0
8
Address High
Byte
A7 A8
Submit Documentation Feedback
A15
Read Status Memory Until
End of Page
Read and
Verify 16-bit
CRC
of command,
address and
data
Copyright © 2011–2014, Texas Instruments Incorporated
Product Folder Links: bq2026
bq2026
www.ti.com
SLUS938A – DECEMBER 2011 – REVISED OCTOBER 2014
Figure 7. READ STATUS Command
Read
Status
Flow
Write
Status
Flow
Master TX:
16-bit address, A
Master TX:
16-bit address, A
Master RX:
8-bit data at A
A = 0x0107?
A=A+1
NO
Master TX:
8-bit data, D
Master RX:
CRC of M/F cmd, A & D
YES
Master RX:
CRC of preloaded
A[15:0] & shifted D
Master TX:
Programming Pulse
Master RX:
CRC of all data transmitted
Master RX:
D
ROM
Function
Flow
A = 0x0107?
Master TX:
8-bit data, D
CRC =
A[15:0]
NO
A=A+1
YES
ROM
Function
Flow
Figure 8. Status Memory Read and Write Flowchart
Submit Documentation Feedback
Copyright © 2011–2014, Texas Instruments Incorporated
Product Folder Links: bq2026
9
bq2026
SLUS938A – DECEMBER 2011 – REVISED OCTOBER 2014
www.ti.com
7.4.9 Write Memory
The Write Memory command is used to program the 1536-bit EPROM memory field. The 1536-bit memory field
is programmed in 1-byte segments. Data is first written into an 1-byte RAM buffer. The contents of the RAM
buffer is then ANDed with the contents of the EPROM memory field when the programming command is issued.
Figure 9 illustrates the sequence of events for programming the EPROM memory field. After issuing a ROM
command, the host issues the Write Memory command, 0Fh, followed by the low byte and then the high byte of
the starting address. The host then transmits 1 byte of data to the bq2026.
a 16-bit CRC is calculated and transmitted based on the command, address and data. If this CRC agrees with
the CRC calculated by the host, the host applies the programming voltage for at least 480 μs or tEPROG.
If at any time during the Write Memory process, the CRC read by the host is incorrect, a reset pulse must be
issued, and the entire sequence must be repeated.
The Write Data Memory command sequence can be terminated at any point by issuing a reset pulse except
during the program pulse period tPROG.
NOTE
The bq2026 responds with the data from the selected EPROM address sent least
significant-bit first. This response should be checked to verify the programmed byte. If the
programmed byte is incorrect, then the host must reset the part and begin the write
sequence again.
For both of these cases, the decision to continue programming is made entirely by the host, because the bq2026
is not able to determine if the 16-bit CRC calculated by the host agrees with the 16-bit CRC calculated by the
bq2026.
Prior to programming, bits in the 1536-bit EPROM data field appear as logical 1s.
10
Submit Documentation Feedback
Copyright © 2011–2014, Texas Instruments Incorporated
Product Folder Links: bq2026
bq2026
www.ti.com
SLUS938A – DECEMBER 2011 – REVISED OCTOBER 2014
Read
Memory
Flow
Write
Memory
Flow
Master TX:
16-bit address, A
Master TX:
16-bit address, A
Master RX:
8-bit data at A
A = 0x00BF?
A=A +1
NO
Master TX:
8-bit data, D
Master RX:
CRC of M/F cmd, A & D
Master RX:
CRC of preloaded
A[15:0] & shifted D
YES
Master RX:
CRC of all data transmitted
Master TX:
Programming Pulse
CRC = A[15:0]
Master RX: D
ROM
Function
Flow
Master TX:
8-bit data, D
A = 0x00BF?
A=A+1
NO
YES
ROM
Function
Flow
Figure 9. General Use OTP Memory Read and Write Flowchart
7.4.10 Write Status
The Write Status command is used to program the EPROM Status data field after the bq2026 has been selected
by a ROM command
The flow chart in Figure 9 illustrates that the host issues the Write Status command, 55h, followed by the
address low byte and then the address high byte followed by the byte of data to be programmed.
NOTE
Individual bytes of address and data are transmitted LSB first. a 16-bit CRC of the
command byte, address bytes, and data byte is computed by the bq2026 and read back
by the host to confirm that the correct command word, starting address, and data byte
were received.
If the CRC read by the host is incorrect, a reset pulse must be issued and the entire sequence must be repeated.
If the CRC received by the host is correct, the programming voltage, VPP is applied to the SDQ pin for period
tPROG. Prior to programming, the first 7 bytes of the EPROM STATUS data field appear as logical 1s. For each bit
in the data byte provided by the host that is set to a logical 0, the corresponding bit in the selected byte of the
EPROM STATUS data field is programmed to a logical 0 after the programming pulse has been applied at the
byte location.
Submit Documentation Feedback
Copyright © 2011–2014, Texas Instruments Incorporated
Product Folder Links: bq2026
11
bq2026
SLUS938A – DECEMBER 2011 – REVISED OCTOBER 2014
www.ti.com
After the programming pulse is applied and the data line returns to VPU, the host issues eight read time slots to
verify that the appropriate bits have been programmed. The bq2026 responds with the data from the selected
EPROM STATUS address sent least significant bit first. This response should be checked to verify the
programmed byte. If the programmed byte is incorrect, then the host must reset the device and begin the write
sequence again. If the bq2026 EPROM data byte programming was successful, the bq2026 automatically
increments its address counter to select the next byte in the STATUS MEMORY data field. The least significant
byte of the new two-byte address is also loaded into the 16-bit CRC generator as a starting value. The host
issues the next byte of data using eight write time slots.
As the bq2026 receives this byte of data into the RAM buffer, it also shifts the data into the CRC generator that
has been preloaded with the LSB of the current address and the result is a 16-bit CRC of the new data byte and
the new address. After supplying the data byte, the host reads this 16-bit CRC from the bq2026 with eight read
time slots to confirm that the address incremented properly and the data byte was received correctly. If the CRC
is incorrect, a Reset Pulse must be issued and the Write Status command sequence must be restarted. If the
CRC is correct, the host issues a programming pulse and the selected byte in memory is programmed.
NOTE
The initial write of the Write Status command, generates a 16-bit CRC value that is the
result of shifting the command byte into the CRC generator, followed by the two-address
bytes, and finally the data byte. Subsequent writes within this Write Status command due
to the bq2026 automatically incrementing its address counter generates a 16-bit CRC that
is the result of loading (not shifting) the LSB of the new (incremented) address into the
CRC generator and then shifting in the new data byte.
For both of these cases, the decision to continue programming the EPROM Status registers is made entirely by
the host, because the bq2026 is not able to determine if the 16-bit CRC calculated by the host agrees with the
16-bit CRC calculated by the bq2026. If an incorrect CRC is ignored and a program pulse is applied by the host,
incorrect programming could occur within the bq2026. Also note that the bq2026 always increments its internal
address counter after the receipt of the eight read time slots used to confirm the programming of the selected
EPROM byte. The decision to continue is again made entirely by the host, therefore if the EPROM data byte
does not match the supplied data byte but the master continues with the Write Status command, incorrect
programming could occur within the bq2026. The Write Status command sequence can be ended at any point by
issuing a reset pulse.
Table 3. Command Code Summary
COMMAND
(HEX)
DESCRIPTION
33h
Read serialization ROM and CRC
55h
Match serialization ROM
CCh
Skip serialization ROM
F0h
Read memory and field CRC
AAh
Read EPROM status
0Fh
Write memory
55h
Write EPROM status
CATEGORY
ROM Commands Available in Command Level I
Memory Function Commands
Available in Command Level II
7.4.11 SDQ Signaling
All SDQ signaling begins with initializing the device, followed by the host driving the bus low to write a 1 or 0, or
to begin the start frame for a bit read. Figure 10 shows the initialization timing, whereas Figure 11 and Figure 12
show that the host initiates each bit by driving the data bus low for the start period, tWSTRB / tRSTRB. After the bit is
initiated, either the host continues controlling the bus during a write, or the bq2026 responds during a read.
12
Submit Documentation Feedback
Copyright © 2011–2014, Texas Instruments Incorporated
Product Folder Links: bq2026
bq2026
www.ti.com
SLUS938A – DECEMBER 2011 – REVISED OCTOBER 2014
7.4.12 Reset and Presence Pulse
If the data bus is driven low for more than 120 μs, the bq2026 may be reset. Figure 10 shows that if the data bus
is driven low for more than 480 μs, the bq2026 resets and indicates that it is ready by responding with a
presence pulse.
RESET
(Sent by Host)
VPU
VIH
VIL
Presence Pulse
(Sent by bq2026)
t PPD
t RST
t PP
t RSTREC
Figure 10. Reset Timing Diagram
7.4.13 Write
The Write bit timing diagram in Figure 11 shows that the host initiates the transmission by issuing the tWSTRB
portion of the bit and then either driving the data bus low for a write 0, or releasing the data bus for a write 1.
V PU
Write ”1”
V IH
V IL
Write ”0”
t rec
t WSTRB
t WDSU
t WDH
Figure 11. Write Bit Timing Diagram
7.4.14 Read
The Read bit timing diagram in Figure 12 shows that the host initiates the transmission of the bit by issuing the
tRSTRB portion of the bit. The bq2026 then responds by either driving the data bus low to transmit a read 0, or
releasing the data bus to transmit a read 1.
VPU
Read ”1”
V IH
V IL
Read ”0”
t RSTRB
t REC
t ODD
t ODHO
Figure 12. Read Bit Timing Diagram
7.4.15 Program Pulse
Figure 13 shows the program pulse timing.
VPP
VPU
tPSU
tPFE
tPRE
tPREC
tEPROG
VSS
Figure 13. Program Pulse Timing Diagram
Submit Documentation Feedback
Copyright © 2011–2014, Texas Instruments Incorporated
Product Folder Links: bq2026
13
bq2026
SLUS938A – DECEMBER 2011 – REVISED OCTOBER 2014
www.ti.com
7.4.16 Idle
If the bus is high, the bus is in the idle state. Bus transactions can be suspended by leaving the data bus in idle.
Bus transactions can resume at any time from the idle state.
7.4.17 CRC Generation
The bq2026 has a 8-bit CRC stored in the most significant byte of the 64-bit ROM. The bus master computes a
CRC value from the first 56 bits of the 64-bit ROM and compares it to the value stored within the bq2026 to
determine if the ROM data has been received error-free by the bus master. The equivalent polynomial function of
this CRC is shown in Figure 14.
Under certain conditions, the bq2026 also generates a 16-bit CRC value using the polynomial function is shown
in Figure 15 and provides this value to the bus master which validates the transfer of command, address, and
data bytes from the bus master to the bq2026. The bq2026 computes a 16-bit CRC for the command, address,
and data bytes received for the Write Memory and the Write Status commands, and then outputs this value to
the bus master which confirms proper transfer. Similarly, the bq2026 computes a 16-bit CRC for the command
and address bytes received from the bus master for the Read Memory, and Read Status commands to confirm
that these bytes have been received correctly.
In each case, where a CRC is used for data transfer validation, the bus master must calculate a CRC value
using the polynomial function in Figure 14 or Figure 15 and compares the calculated value to either the 8-bit
CRC value stored in the 64-bit ROM portion of the bq2026 (for ROM reads) or the 16-bit CRC value computed
within the bq2026. The comparison of CRC values and the decision to continue with an operation are determined
entirely by the bus master. No circuitry on the bq2026 prevents a command sequence from proceeding if the
CRC stored in or calculated by the bq2026 does not match the value generated by the bus master. Proper use of
the CRC can result in a communication channel with a high level of integrity.
CLK
DAT
Q
D
Q
D
R
Q
D
R
R
+
Q
D
R
+
Q
D
Q
D
R
R
Q
D
R
+
Q
D
R
Figure 14. 8-bit CRC Generator Circuit (X8 + X5 + X4 + 1) for Serial Number Read
SPACER
CLK
DAT
Q
D
Q
D
R
Q
D
R
Q
D
R
Q
D
Q
D
R
R
Q
D
R
Q
D
R
Q
D
R
Q
D
R
Q
D
Q
D
R
R
Q
D
R
Q
D
R
R
Q
D
Q
D
R
R
Figure 15. 16-bit CRC Generator Circuit (X16 + X15 + X2 + 1) for Memory Interface
14
Submit Documentation Feedback
Copyright © 2011–2014, Texas Instruments Incorporated
Product Folder Links: bq2026
bq2026
www.ti.com
SLUS938A – DECEMBER 2011 – REVISED OCTOBER 2014
8 Device and Documentation Support
8.1 Trademarks
SDQ is a trademark of Texas Instruments.
All other trademarks are the property of their respective owners.
8.2 Electrostatic Discharge Caution
This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more
susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.
8.3 Glossary
SLYZ022 — TI Glossary.
This glossary lists and explains terms, acronyms, and definitions.
9 Mechanical, Packaging, and Orderable Information
The following pages include mechanical, packaging, and orderable information. This information is the most
current data available for the designated devices. This data is subject to change without notice and revision of
this document. For browser-based versions of this data sheet, refer to the left-hand navigation.
Submit Documentation Feedback
Copyright © 2011–2014, Texas Instruments Incorporated
Product Folder Links: bq2026
15
PACKAGE OPTION ADDENDUM
www.ti.com
25-Sep-2021
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
(4/5)
(6)
BQ2026DBZR
ACTIVE
SOT-23
DBZ
3
3000
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-20 to 70
WAIS
BQ2026LPR
ACTIVE
TO-92
LP
3
2000
RoHS & Green
SN
N / A for Pkg Type
-20 to 70
BQ2026
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of