DS2784G+ Maxim Integrated Products, DS2784G+ Datasheet
DS2784G+
Specifications of DS2784G+
Related parts for DS2784G+
DS2784G+ Summary of contents
Page 1
... Portable GPS Navigation Modes and commands are capitalized for clarity. 1-Wire is a registered trademark of Maxim Integrated Products, Inc. ORDERING INFORMATION PART DS2784G+ DS2784G+T&R +Denotes a lead(Pb)-free/RoHS-compliant package. T&R = Tape and reel. 1-Cell Stand-Alone Fuel Gauge IC with FEATURES Precision Voltage, Temperature, and Current ...
Page 2
ABSOLUTE MAXIMUM RATINGS Voltage Range on PLS Pin Relative to V Voltage Range on CP Pin Relative to V Voltage Range on DC Pin Relative to V Voltage Range on CC Pin Relative to V Voltage Range on All Other ...
Page 3
PARAMETER Output Low: DC DQ, PIO Voltage Range DQ, PIO Input-Logic High DQ, PIO Input-Logic Low DQ, PIO Output-Logic Low DQ, PIO Pullup Current DQ, PIO Pulldown Current DQ Input Capacitance DQ Sleep Timeout PIO, DQ Wake Debounce SHA-1 COMPUTATION ...
Page 4
EEPROM RELIABILITY SPECIFICATION (V = 2.5V to 4.6V -20C to +70C, unless otherwise noted PARAMETER EEPROM Copy Time EEPROM Copy Endurance ELECTRICAL CHARACTERISTICS: 1-Wire Interface, Standard (V = 2.5V to 4.6V -20C to +70C, ...
Page 5
TYPICAL OPERATION CHARACTERISTICS CC FET Turn Off DC FET Turn Off ...
Page 6
COC Delay DOC Delay ...
Page 7
SC Delay OV Delay ...
Page 8
UV Delay ...
Page 9
TYPICAL OPERATING CIRCUIT PIN DESCRIPTION PIN NAME 1 V Power-Supply Input. Chip supply input. Bypass with 0.1µ CTG Connect to Ground 3 V Device Ground. Chip ground and battery-side sense resistor input. SS Battery Voltage-Sense Input. ...
Page 10
FETs in a low-side configuration. The thresholds for overvoltage, overcurrent, and short-circuit current are user programmable for easy customization to each cell and application. The 32-bit wide SHA-1 engine with 64-bit secret and 64-bit challenge words ...
Page 11
POWER MODES The DS2784 has two power modes: Active and Sleep. On initial power-up, the DS2784 defaults to Active mode. In Active mode, the DS2784 is fully functional with measurements and capacity estimation registers continuously updated. The protector circuit monitors ...
Page 12
Figure 1. Sleep Mode State Diagram CONTROL REGISTER FORMAT All control register bits are read and write accessible. The control register is recalled from parameter EEPROM memory at power-up. Register bit values can be modified in shadow RAM after power-up. ...
Page 13
PMOD—Power Mode Enable. A value of 1 allows the DS2784 to enter Sleep mode when DQ is low for t value of 0 disables DQ related transitions to Sleep mode. RNAOP—Read Net Address Op Code. A value of 0 selects ...
Page 14
FETs the device does not enter sleep mode for an UV condition (UVEN=0) then the FETs will turn on once V > Overcurrent, Charge Direction (COC). Charge current develops a negative voltage on ...
Page 15
Summary. All the protection conditions previously described are logic ANDed to affect the CC and DC outputs (Overvoltage) AND (Undervoltage) AND (Overcurrent, Charge Direction) AND (Protection Register Bit CE) (Undervoltage) AND (Overcurrent, Either Direction) AND (Short Circuit) DC ...
Page 16
PROTECTOR THRESHOLD REGISTER FORMAT The 8-bit threshold register consists of bit fields for setting the overvoltage threshold, charge overcurrent threshold, discharge overcurrent threshold, and short-circuit threshold for the protection circuit. BIT 7 BIT 6 VOV4 VOV3 Table 2. VOV Threshold ...
Page 17
VOLTAGE MEASUREMENT Battery voltage is measured every 440ms on the V and a 4.88mV resolution. The value is stored in the voltage register in two’s complement form and is updated every 440ms. Voltages above the maximum register value are reported ...
Page 18
The average current register reports an average current level over the preceding 28s. The register value is updated every 28s in two’s complement form, and represents an average of the eight preceding current register values. AVERAGE CURRENT REGISTER FORMAT MSB—ADDRESS ...
Page 19
CURRENT MEASUREMENT CALIBRATION The DS2784’s current measurement gain can be adjusted through the RSGAIN register, which is factory calibrated to meet the data sheet-specified accuracy. RSGAIN is user accessible and can be reprogrammed after module or pack manufacture to improve ...
Page 20
Read and write access is allowed to the ACR. The ACR must be written MSB first then LSB. Whenever the ACR is written, the fractional accumulation result bits are cleared. The write must be completed in 3.5s (one ACR update ...
Page 21
... TBP12, TBP23, and TBP34 in Figure 4) are programmable in 1°C increments from -128°C to +40°C. The slope or derivative for segments and 4 are also programmable over a range 15,555ppm, in steps of 61ppm. FuelPack is a trademark of Dallas Semiconductor, a wholly owned subsidiary of Maxim Integrated Products, Inc. FULL(T) Capacity Look-up ...
Page 22
Figure 4. Cell Model Example Diagram SEGMENT 1 100% Full—The full curve defines how the full point of a given cell varies over temperature for a given charge termination. The application’s charge termination method should be used to determine the ...
Page 23
Table 6. Example Cell Characterization Table (Normalized to +40°C) Manufacturer’s Rated Cell Capacity: 1000mAh Charge Voltage: 4.2V Active Empty (V): 3.0V Sense Resistor: 0.020 TBP12 Segment -12C Breakpoints +40C Nominal (mAh) Full 1051 Active Empty Standby Empty Figure 5. Lookup ...
Page 24
IMIN is located in the parameter EEPROM block. Active Empty Voltage (VAE)—VAE stores the voltage threshold used to detect the active empty point. The ...
Page 25
ACR Housekeeping The ACR value is adjusted occasionally to maintain the coulomb count within the model curve boundaries. When the battery is charged to full (CHGTF set), the ACR is set equal to the age scaled full lookup value at ...
Page 26
LEARNF—Learn Flag. LEARNF indicates that the current charge cycle can be used to learn the battery capacity. LEARNF is set when the active-empty point is detected. This occurs when the voltage register value drops below the VAE threshold AND the ...
Page 27
MSB—ADDRESS 02h MSb Remaining Standby Absolute Capacity (RSAC) [mAh]—RSAC reports the remaining battery capacity available under the current temperature conditions to the standby-empty point capacity in absolute units of milliamp-hours (mAhr). RSAC ...
Page 28
Calculation of Results RAAC [mAh] = (ACR[mVh] - AE(T) * FULL40[mVh Note 1/R SNSP SNS RSAC [mAh] = (ACR[mVh] - SE(T) * FULL40[mVh Note 1/R SNSP SNS RARC [%] = 100% * ...
Page 29
BL1—Parameter EEPROM Block 1 Lock Flag this read-only bit indicates that EEPROM block 1 (addresses 60h to 7Fh) is locked (read only) while a 0 indicates block 1 is unlocked (read/write). BL0—User EEPROM Block 0 Lock Flag. ...
Page 30
Table 7. Parameter EEPROM Memory Block ADDRESS DESCRIPTION (HEX) 60 CONTROL—Control Register 61 AB— Accumulation Bias 62 AC—Aging Capacity MSB 63 AC—Aging Capacity LSB 64 VCHG—Charge Voltage 65 IMIN—Minimum Charge Current 66 VAE—Active-Empty Voltage 67 IAE—Active-Empty Current 68 Active Empty ...
Page 31
Table 8. Memory Map ADDRESS (HEX) 00 Protection Register 01 Status Register 02 RAAC MSB 03 RAAC LSB 04 RSAC MSB 05 RSAC LSB 06 RARC 07 RSRC 08 Average Current Register MSB 09 Average Current Register LSB 0A Temperature ...
Page 32
AUTHENTICATION Authentication is performed using a FIPS-180-compliant SHA-1 one-way hash algorithm on a 512-bit message block. The message block consists of a 64-bit secret, a 64-bit challenge and 384 bits of constant data. Optionally, the 64-bit net address replaces 64 ...
Page 33
SECRET MANAGEMENT FUNCTION COMMANDS CLEAR SECRET [5Ah]. This command sets the 64-bit secret to all 0s (0000 0000 0000 0000h). The host must wait t for the DS2784 to write the new secret value to EEPROM. See Figure 13 for ...
Page 34
CRC GENERATION The DS2784 has an 8-bit CRC stored in the most significant byte of its 1-Wire net address and generates a CRC during some command protocols. To ensure error-free transmission of the address, the host system can compute a ...
Page 35
The 1-Wire bus must have a pullup resistor at the bus-master end of the bus. A value of between 2k and 5k is recommended. The idle state for the 1-Wire bus is high. If, for any reason, a bus transaction ...
Page 36
... If the lock bit setting the lock bit to 1 does not immediately precede the Lock command, the Lock command has no effect. The Lock command is permanent; a locked block can never be written again. iButton is a registered trademark of Maxim Integrated Products, Inc. time to execute, starting on the next falling edge after the address is ...
Page 37
Table 11. All Function Commands COMMAND Write Challenge Compute MAC Without ROM ID and Return MAC Compute MAC With ROM ID and Return MAC Clear Secret Compute Next Secret Without ROM ID Compute Next Secret With ROM ID Lock Secret ...
Page 38
DS2784: 1-Cell Stand-Alone Fuel Gauge IC with Li+ Protector and SHA-1 Authentication Table 12. Guide to Function Command Requirements COMMAND Write Challenge Compute MAC Compute Next Secret Clear/Lock Secret, Set/Clear Overdrive Read Data Write Data Copy Data Recall Data Lock ...
Page 39
DS2784: 1-Cell Stand-Alone Fuel Gauge IC with Li+ Protector and SHA-1 Authentication Figure 11. Compute Next Secret Function Command Figure 12. Copy Function Command 1-Wire SKIP ROM Copy Reset Cmd Cmd Presence Pulse Figure 13. Clear/Lock Secret, Set/Clear Overdrive Function ...
Page 40
I/O SIGNALING The 1-Wire bus requires strict signaling protocols to ensure data integrity. The four protocols used by the DS2784 are as follows: the initialization sequence (reset pulse followed by presence pulse), write 0, write 1, and read data. The ...
Page 41
Figure 15. 1-Wire Write and Read-Time Slots ...
Page 42
PACKAGE INFORMATION For the latest package outline information and land patterns www.maxim-ic.com/packages. Note that a “+”, “#”, or “-“ in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing ...
Page 43
... Maxim reserves the right to change the circuitry and specifications without notice at any time 2010 Maxim Integrated Products DESCRIPTION maximum operating range in the Electrical Characteristics for pin monitored for UV release condition. IN voltage” text in the Voltage Measurement Maxim is a registered trademark of Maxim Integrated Products. PAGES CHANGED 2– 5– ...