DS2437S/T&R Maxim Integrated Products, DS2437S/T&R Datasheet
DS2437S/T&R
Specifications of DS2437S/T&R
Related parts for DS2437S/T&R
DS2437S/T&R Summary of contents
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FEATURES ® Unique 1-Wire interface requires only one port pin for communication Provides unique 64-bit serial number to battery packs Eliminates thermistors by sensing battery temperature on-chip On-board A/D converter allows monitoring of battery voltage for end-of-charge and end-of- ...
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Applications for the smart battery pack monitor include portable computers, portable/cellular telephones, and handheld instrumentation battery packs in which it is critical to monitor real-time battery performance. Used in conjunction with a microcontroller in the battery pack or host system, ...
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Control function commands may be issued which instruct the DS2437 to perform a temperature measurement or battery voltage A/D conversion. The result of these measurements will be placed in the DS2437’s memory map, and may be read by issuing a ...
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OPERATION – MEASURING TEMPERATURE The DS2437 measures temperatures through the use of an onboard proprietary temperature measurement technique. The temperature reading is provided in a 13-bit, two’s complement reading, which provides 0.03125°C of resolution. Table 1 describes the exact relationship ...
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Voltage is expressed in this register in scaled binary format, as outlined in Table 2. Note that while codes exist for values below 2.7V, accuracy of the ADC and the limitation on the DS2437’s supply voltage make it unlikely that ...
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The current is measured by the ADC with a signed 10-bit (0.004883C) resolution, and the last completed measurement is placed in the CURRENT REGISTER in a sign-extended 2’s-complement format. This register is scaled such that a count of 205 current ...
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The ICA is a scaled 8-bit (0.01C resolution) volatile binary counter which represents the amount of capacity remaining in the battery in terms of the full capacity (1C), normalized to a count of 100 an ICA count of 100 represents ...
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The CCA/DCA will accumulate charging/discharging current, and the counter information will be shadowed to EEPROM each time the respective counter increments by 0.32C. The memory location is reserved for the CCA/DCA, and the entire page SHOULD NOT be written ...
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OPERATION – REAL TIME CLOCK The 32.768 kHz crystal oscillator is used as the time base for the timekeeping functions. The timekeeping functions are double-buffered, allowing the master to read time without the data changing while it is being read. ...
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LASERED ROM Each DS2437 contains a unique ROM code that is 64 bits long. The first 8 bits are a 1-Wire family code (DS2437 code is 1Eh). The next 48 bits are a unique serial number. The last 8 ...
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CRC CODE Figure 4 ROM FUNCTIONS FLOWCHART Figure DS2437 ...
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MEMORY/CONTROL FUNCTIONS FLOWCHART Figure DS2437 YES ...
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MEMORY/CONTROL FUNCTIONS FLOWCHART Figure 6 Cont'd DS2437 RECALLS EEPROM PAGE INTO SP PAGE DS2437 X X ...
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MEMORY MAP The DS2437’s memory is organized as shown in Figure 7. The memory consists of a scratchpad RAM and storage SRAM/EEPROM. The scratchpad helps insure data integrity when communicating over the 1-Wire bus. Data is first written to the ...
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ADB = A/D Converter Busy Flag A/D conversion in progress on battery voltage conversion complete measurement being made. An A/D conversion takes approximately 10 ms Don’t care Bytes 1 and 2 of ...
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DS2437 MEMORY MAP Figure 7 1-Wire BUS SYSTEM The 1-Wire bus is a system which has a single bus master and one or more slaves. The DS2437 behaves as a slave. The discussion of this bus system is broken down ...
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The idle state for the 1-Wire bus is high. If for any reason a transaction needs to be suspended, the bus MUST be left in the idle state if the transaction is to resume. Infinite recovery time can occur between ...
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Search ROM [F0h] When a system is initially brought up, the bus master might not know the number of devices on the 1-Wire bus or their 64-bit ROM codes. The search ROM command allows the bus master to use a ...
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The bus master writes a 0-bit. This deselects ROM1 leaving ROM4 as the only device still connected. 9. The bus master reads the remainder of the ROM bits for ROM4 and continues to access the part if desired. This ...
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Copy Scratchpad [48hxxh] This command copies the scratchpad page xxh into the EEPROM / SRAM memory page xxh of the DS2437. After issuing this command, the user must write a page number to direct which page of memory the scratchpad ...
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INSTRUCTION DESCRIPTION Initiates temperature Convert T conversion Initiates voltage A/D Convert V conversion NOTES: 1. Temperature conversion takes second. 2. A/D conversion takes ms. 3. EEPROM write takes ms. Sample Command ...
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Sample Command Sequence Table 8 Example: Bus Master issues a temperature and voltage conversion, then reads the temperature, battery voltage, battery current, all on a single DS2437. MASTER MODE DATA (LSB FIRST Presence Presence ...
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Sample Command Sequence Table 9 Example: Assuming a single DS2437 is configured for its current accumulators to function, this sequence allows the Bus Master to read the three current accumulators. MASTER MODE DATA (LSB FIRST Presence TX TX ...
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I/O SIGNALING The DS2437 requires strict protocols to insure data integrity. The protocol consists of several types of signaling on one line: reset pulse, presence pulse, write 0, write 1, read 0, and read 1. All of these signals, with ...
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Read Time Slots The host generates read time slots when data read from the DS2437. A read time slot is initiated when the host pulls the data line from a logic high level to logic low level. ...
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READ / WRITE TIMING DIAGRAM Figure DS2437 ...
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DETAILED MASTER READ 1 TIMING Figure 11 RECOMMENDED MASTER READ 1 TIMING Figure DS2437 ...
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ABSOLUTE MAXIMUM RATINGS* Voltage on VDD and VAD, Relative to Ground Voltage on VSENS+, VSENS-, Relative to Ground Voltage on Any Pin Relative to Ground Operating Temperature Storage Temperature Soldering Temperature * This is a stress rating only and functional ...
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ELECTRICAL CHARACTERISTICS: VOLTAGE A/D CONVERTER PARAMETER SYMBOL A/D Error VAD V Input Range Input Range Input Range V DD Resolution Conversion Time t CONVV No Missing Code Temperature Range Monotonicity ELECTRICAL CHARACTERISTICS: CURRENT A/D ...
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AC ELECTRICAL CHARACTERISTICS: 1-WIRE INTERFACE PARAMETER SYMBOL Time Slot t Recovery Time t Write 0 Low Time t LOW0 Write 1 Low Time t LOW1 Read Data Valid t Reset Time High t RSTH Reset Time Low t Presence Detect ...
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TIMING DIAGRAMS Figure 14 1-WIRE WRITE 1 TIME SLOT 1-WIRE WRITE 0 TIME SLOT 1-WIRE READ TIME SLOT 1-WIRE RESET PULSE 1-WIRE PRESENCE DETECT DS2437 ...