DS2435 ,Battery identification chip with time/temperature histogramPIN DESCRIPTIONPIN PIN16-PIN SSOP PR-35 SYMBOL DESCRIPTION8, 9 1 GNDGround pin.12 DQ Data Input/Out ..
DS2435 ,Battery identification chip with time/temperature histogramPIN DESCRIPTIONGND - GroundDQ - Data In/OutV - Supply VoltageDDNC - No ConnectDESCRIPTIONThe DS2435 ..
DS2435 ,Battery identification chip with time/temperature histogramApplications include portable computers,portable/cellular phones, consumer NC 6 11NCelectronics, an ..
DS2435 ,Battery identification chip with time/temperature histogramFEATURES PACKAGE OUTLINE Provides unique ID number to battery packs PR-35 PACKAGE Eliminates ther ..
DS2436 ,Battery ID/Monitor ChipPIN DESCRIPTIONGND - GroundDQ - Data In/OutV - Supply/Battery ConnectionDDDESCRIPTIONThe DS2436 Bat ..
DS2436Z ,Battery ID/Monitor Chipblock diagram of Figure 1 shows the major components of the DS2436. The DS2436 has sevenmajor data ..
E53NA50 ,NABSOLUTE MAXIMUM RATINGSSymbol Parameter Value UnitV Drain-source Voltage (V =0) 500 VDS GSV 500 VD ..
EA2-12 ,COMPACT AND LIGHTWEIGHTAPPLICATIONSElectronic switching systems, PBX, key telephone systems, automatic test equipment and ..
EA2-12NU ,COMPACT AND LIGHTWEIGHTFEATURESª Low power consumptionª Compact and light weightª 2 form c contact arrangementª Low magnet ..
EA2-12S ,COMPACT AND LIGHTWEIGHTFEATURESª Low power consumptionª Compact and light weightª 2 form c contact arrangementª Low magnet ..
EA2-12TNU ,COMPACT AND LIGHTWEIGHTAPPLICATIONSElectronic switching systems, PBX, key telephone systems, automatic test equipment and ..
EA2-4.5NU ,COMPACT AND LIGHTWEIGHTAPPLICATIONSElectronic switching systems, PBX, key telephone systems, automatic test equipment and ..
DS2435
Battery identification chip with time/temperature histogram
FEATURESProvides unique ID number to battery packsEliminates thermistors by sensing battery
temperature on-chipElapsed time counter provides indication of
battery usage/storage timeTime/temperature histogram function
provides essential information for
determining battery self-discharge256-bit nonvolatile user memory available for
storage of user data such as gas gauge and
manufacturing information.Operating range of -40°C to +85°CApplications include portable computers,portable/cellular phones, consumer
electronics, and handheld instrumentation.
PACKAGE OUTLINE
PIN DESCRIPTIONGND - Ground
DQ - Data In/Out
VDD - Supply VoltageNC - No Connect
DESCRIPTIONThe DS2435 Battery Identification Chip with Time/Temperature Histogram provides a convenient
method of tagging and identifying battery packs by manufacturer, chemistry, or other identifying
parameters. The DS2435 allows the battery pack to be coded with a unique identification number and also
store information regarding the battery life and charge/discharge characteristics in its nonvolatilememory.
The DS2435 performs the essential function of monitoring battery temperature without the need for a
thermistor in the battery pack. A time/temperature histogram function stores the amount of time that the
battery has been in one of its eight user definable temperature bands, allowing more accurate self-discharge calculations to be carried out by the user for determining remaining battery capacity. The on-
board elapsed time counter provides a method that can even determine the amount of time that a battery
DS2435
Battery Identification Chip
with Time/Temperature HistogramGND
VDD
GND
GND
See Mech. Drawings Section
PR-35 PACKAGE
123
DS2435
Information is sent to/from the DS2435 over a 1-Wire interface, reducing the number of battery pack
connectors to only three; power, ground, and the 1-Wire interface.
DETAILED PIN DESCRIPTION
OVERVIEWThe DS2435 has six major components: 1) Scratchpad Memory, 2) Nonvolatile Memory, 3) On-boardSRAM, 4) Temperature Sensor, 5) ID Register, and 6) Elapsed Time Counter. All data is read and written
least significant bit first.
Access to the DS2435 is over a 1-Wire interface. Charging parameters, battery chemistry, gas gauge
information, and other user data would be stored in the DS2435, allowing this information to remainpermanently in the battery pack. Nonvolatile (E2) RAM holds information even if the battery goes dead;
as long as the battery remains within typical charge/discharge operating range, the SRAM provides
battery-backed storage of information.
DS2435 BLOCK DIAGRAM Figure 1
DS2435
OVERVIEW - TIME/TEMPERATURE HISTOGRAMPeriods of storage are normal for most battery-powered applications. During this storage time, little or no
current is actually drawn from the battery; batteries will, however, lose capacity during this storage time
due to parasitic side reactions in the cell and other electrochemical mechanisms. This loss of capacity is
termed self-discharge.
Since self-discharge is the result of electrochemical reactions, its rate is dependent upon the cell
temperature. Knowing the time spent in certain temperature ranges during the storage time of the battery,
these temperature effects may be factored into a calculation of self-discharge for the battery. This will
allow a more accurate determination of retained battery capacity.
The DS2435 measures, tabulates, and stores this information in the battery pack. It periodically measures
the battery temperature, and updates the appropriate temperature “bin” of the time/temperature histogram
with the time spent in that temperature range. The resulting histogram data could appear graphically as
shown in Figure 2.
The DS2435 allows for eight temperature ranges, or bins, to be specified by fixing the values of the bin
limits, TA through TG. Once specified, the time spent in each of the bins (bin 1 being anything less than
TA, bin 2 being temperature greater than or equal to TA but less than TB, etc., and bin 8 being anything
greater than or equal to TG) is recorded (t1 being the time spent in bin 1, t2 the time spent in bin 2, etc.).
Using this information and data from the battery manufacturer regarding retained capacity, the actualbattery capacity remaining may be closely approximated by the user.
TIME/TEMPERATURE HISTOGRAM Figure 2
DS2435
MEMORYThe DS2435’s memory is divided into five pages, each page filling 32 bytes of address space. Not all of
the available addresses are used, however. Refer to the memory map of Figure 4 to see actual addresses
which are available for use.
The first three pages of memory consist of a scratchpad RAM and then either a nonvolatile RAM (pages 1and 2) or SRAM (page 3). The scratchpads help insure data integrity when communicating over the 1-
Wire bus. Data is first written to the scratchpad where it can be read back. After the data has been
verified, a copy scratchpad command will transfer the data to the RAM (NV or SRAM). This process
insures data integrity when modifying the memory.
The fourth page of memory consists of registers which contain the measured temperature value,
time/temperature histogram registers, elapsed time counter, and status registers for the device; these
registers are made from SRAM cells.
The fifth page of memory holds the ID number for the device, the cycle count registers and the histogrambin limits in E2 RAM, making these registers nonvolatile under all power conditions.
PAGE 1The first page of memory has 24 bytes. It consists of a scratchpad RAM and a nonvolatile (E2) RAM.
These 24 bytes may be used to store any data the user wishes; such as battery chemistry descriptors,
manufacturing lot codes, gas gauge information, etc.
The nonvolatile portion of this page may be locked to prevent data stored here from being changed
inadvertently. Both the nonvolatile and the scratchpad portions are organized identically, as shown in the
memory map of Figure 4. In this page, these two portions are referred to as NV1 and SP1, respectively.
PAGE 2The second page of memory has 8 bytes. It consists of a scratchpad RAM and a nonvolatile (E2) RAM.These 8 bytes may be used to store any data the user wishes, such as battery chemistry descriptors,
manufacturing lot codes, gas gauge information, etc.
PAGE 3The third page of memory has a full 32 bytes. It consists of a scratchpad RAM and an SRAM. This
address space may be used to store any data the user wishes, such as gas gauge and self-dischargeinformation. Should the battery go dead and power to the DS2435 is lost, this data may also be lost. Data
which must remain even if power to the DS2435 is lost should be placed in either Page 1 or Page 2.
PAGE 4The fourth page of memory is used by the DS2435 to store the converted value of battery temperature, the
time/temperature histogram data, and the elapsed time counter. A 2-byte status register is also provided.
TEMPERATURE REGISTERS (60h-61h)The DS2435 can measure temperature without external components. The resulting temperature
measurement is placed into two temperature registers. These registers are SRAM, and therefore will hold
the values placed in them until the battery voltage falls below the minimum VDD specified. The first
register, at address 60h, provides ½°C resolution for temperatures between 0°C and 127 ½°C, formatted
DS2435
The second register, at address 61h, provides 1°C resolution over the -40°C to +85°C range, formatted asfollows in the binary two’s complement coding as shown in Table 1:
TEMPERATURE/DATA RELATIONSHIPS Table 1
STATUS/CONTROL REGISTER (62h-63h)The status register is a 2-byte register at addresses 62h and 63h (consisting of SRAM). Address 62h is the
least significant byte of the status register, and is currently the only address with defined status bits; the
other byte at address 63h is reserved for future use. The status register is formatted as follows:
where
X = Don’t Care
TB = Temperature Busy flag. 1 = temperature conversion in progress; 0 = temperature
conversion complete, valid data in temperature register.
NVB = Nonvolatile memory busy flag. 1 = Copy from scratchpad to NVRAM in progress, 0 =
nonvolatile memory is not busy. A copy to NVRAM may take from 2 ms to 10 ms (taking
longer at lower supply voltages).
DS2435
t1-t8 REGISTERS (64h-73h)These registers hold the accumulated time values for the time/temperature histogram. t1 corresponds to
the time spent in histogram bin 1, t2 the time spent in bin 2, etc., where the bins are defined by the limits
set in TA-TG as shown in Figure 2. The format for the time value stored in these two-byte registers
depends upon the SAMPLE RATE, and is defined in the paragraph describing the SAMPLE RATE
parameter.
t REGISTER (74h-76h)This 3-byte register is the elapsed time counter, formatted as follows:
The elapsed time counter has an LSB value of 1 minute; the total time which the counter can
accommodate is 224 minutes, or 31.92 years.
Issuing any protocol to the DS2435 prevents the incrementing of the elapsed time counter and histogram
registers until the protocol is cleared by issuing a reset. Therefore, it is imperative that any protocol
issued to the DS2435 be followed by a reset (either after the protocol, if it requires no data, or
immediately following the required data). This is necessary to avoid contention between the counter andhistogram writing process and external processes.
PAGE 5The fifth page of memory holds the battery manufacturer ID number, a 2-byte counter for counting the
number of battery charge/discharge cycles, histogram bin limits, and sample rate.
ID REGISTER (80h and 81h)The ID Register is a 16-bit ROM register that can contain a unique identification code, if purchased from
Dallas Semiconductor. This ID number is programmed by Dallas Semiconductor, is unchangeable, and is
unique to each customer. This ID number may be used to ensure that batteries containing a DS2435 have
the same manufacturer ID number as a charger configured to operate with that battery pack. This feature
may be used to prevent charging of batteries for which the charging circuit has not been designed.
CYCLE COUNTER (82h and 83h)The cycle counter register gives an indication of the number of charge/discharge cycles the battery pack
has been through. This nonvolatile (E2) register is incremented by the user through the use of a protocol
to the DS2435, and is reset by another protocol. The counter is a straight binary counter, formatted as
follows:
DS2435
TA-TG REGISTERS (84h-8Ah)These registers define the boundaries for the temperature bins in the time/temperature histogram, as
shown in Figure 2. These temperature values are expressed in the same temperature format as shown in
Table 1. These limits therefore may be positive or negative values, expressed with 1°C resolution. The
bin limits must be specified in increasing order (i.e., TA
SAMPLE RATE (8Bh)
This register defines the periodic interval at which the DS2435 will take a temperature measurement for
updating the histogram data. Note that this does not affect the actual time needed to perform a
temperature conversion using the Convert T protocol; this sample rate refers only to the periodic interval
at which histogram data is updated.
The sample rate is expressed as follows:S1S0SAMPLE RATE001/2 minute011 minute102 minutes114 minutes001/8 hour011/4 hour101/2 hour111 hour
The interval specified in this register determines the LSB value for the time/temperature histogram
registers, as shown below. Examples of time expressions for a given sample rate are shown in Table 2.
HISTOGRAM REGISTER DATA GIVEN FOR SAMPLE RATE
DS2435
DS2435 MEMORY PARTITIONING Figure 3
DS2435
DS2435 ADDRESSABLE RAM MEMORY MAP Figure 4
DS2435
DS2435 ADDRESSABLE RAM MEMORY RAM (Cont'd) Figure 4
DS2435
EXAMPLE CODES FOR 771 HOURS, 22.5 MINUTES
WITH DIFFERENT SAMPLE RATES Table 2
MEMORY FUNCTION COMMANDS
The protocols necessary for accessing the DS2435 are described in this section. These are summarized in
Table 3, and examples of memory functions are provided in Tables 4 and 5.
PAGE 1 THROUGH PAGE 3 COMMANDS
Read Scratchpad [11h]
This command reads the contents of the scratchpad RAM on the DS2435. This command is followed by a
start byte address. After issuing this command and providing the start address, the user may begin reading
the data. The user may read data through the end of the scratchpad space (address 5Fh), with any reserveddata bits reading all logic 1s. Once the end of the scratchpad is reached the data in address 5Fh will be
read repeatedly until termination of the read scratchpad command.
Write Scratchpad [17h]
This command writes to the scratchpad RAM on the DS2435. This command is followed by a start byte
address. After issuing this command and providing the start address, the user may begin writing data to
the DS2435 scratchpad at the starting byte address.
Copy SP1 to NV1 [22h]
This command copies the entire contents (24 bytes) of Scratchpad 1 (SP1) to its corresponding
nonvolatile memory (NV1). The nonvolatile RAM memory of the DS2435 cannot be written to directly
by the bus master; however, the scratchpad RAM may be copied to the nonvolatile RAM. This prevents
accidental overwriting of the nonvolatile RAM and allows for the data to be written first to thescratchpad, where it can be read back and verified before copying to the nonvolatile RAM. This
command does not use a start address; the entire contents of the scratchpad will be copied to the
nonvolatile RAM. The NVB bit will be set when the copy is in progress. NV1 is made with E2 type
memory cells that will accept at least 50000 changes.
Copy SP2 to NV2 [25h]This command copies the entire contents (8 bytes) of SP2 (user bytes) to its corresponding nonvolatile
memory (NV2). This command does not use a start address; the entire contents of SP2 will be copied to
NV2. The NVB bit will be set when the copy is in progress. NV2 is made with E2 type memory cells that
will accept at least 50000 changes.
Copy SP3 to SRAM [28h]
This command copies the entire contents (32 bytes) of SP3 to its corresponding SRAM. This commanddoes not use a start address; the entire contents of SP3 will be copied to the SRAM.
DS2435
Copy NV1 to SP1 [71h]
This command copies the entire contents (24 bytes) of NV1 to its corresponding scratchpad RAM (SP1).
This command does not use a start address; the entire contents of NV1 will be copied to SP1. The
nonvolatile RAM memory of the DS2435 cannot be read directly by the bus master; however, the
nonvolatile RAM may be copied to the scratchpad RAM.
Copy NV2 to SP2 [77h]
This command copies the entire contents (8 bytes) of NV2 (user bytes) to its corresponding scratchpadRAM (SP2). This command does not use a start address; the entire contents of NV2 will be copied to
SP2. The non-volatile RAM memory of the DS2435 cannot be read directly by the bus master; however,
the nonvolatile RAM may be copied to the scratchpad RAM.
Copy SRAM to SP3 [7Ah]
This command copies the entire contents (32 bytes) of SRAM to its corresponding scratchpad RAM(SP3). This command does not use a start address; the entire contents of SRAM will be copied to
SP3.The SRAM memory of the DS2435 cannot be read directly by the bus master; however, the SRAM
may be copied to the scratchpad RAM.
Lock NV1 [43h]
This command prevents copying SP1 to NV1 and sets the LOCK bit. This is done as an added measure ofdata security, preventing data from being changed inadvertently. NV1 may be copied up into SP1 while
the part is locked. This allows NV1 to be read at any time. However, NV1 cannot be written to through a
Copy SP1 to NV1 command without first unlocking the DS2435.
Unlock NV1 [44h]
This command unlocks NV1 to allow copying SP1 into NV1. This is done as an added measure of data
security, preventing data from being changed inadvertently.
PAGE 4 AND 5 COMMANDS
Convert T [D2h]
This command instructs the DS2435 to initiate a temperature conversion cycle. This sets the TB flag.
When the temperature conversion is done, the TB flag is reset and the current temperature value is placed
in the temperature register. While a temperature conversion is taking place, all other memory functions
are still available for use.
Reset Histogram [E1h]This command resets the accumulated time in all of the histogram temperature registers to zero. In
addition, this command also resets the elapsed time counter to 0. This command does not use a start
address; no further data is required.
Set Clock [E6h]
This command sets the elapsed time counter to a preset value. This command is followed by three bytes
of data, which will be stored at addresses 74h-76h. The transfer of this 3-byte value will occur afterreception of the 24th bit following the protocol, at which time the elapsed time counter will begin
incrementing the counter registers in 1-minute increments.
