RT9426WSC

RT9426 System Side Single Cell Fuel Gauge General Description Features The RT9426 Li-Ion / Li-Polymer battery fuel gauge is a microcontroller peripheral that provides fuel gauging for single-cell battery packs. The RT9426 resides within the battery pack or on the system's main board and manages a non-removable battery or removable battery pack.  The RT9426 reports StateOfCharge, StateOfHealth, FullChargeCapacity, TimeToEmpty and CycleCount based on the Voltaic Gauge with Current Sensing (VGCS) algorithm by using the voltage difference between battery voltage and OCV to calculate the increasing or decreasing SOC, with current sensing compensation to report battery SOC. Voltaic Gauge with Current Sensing algorithm can support smoothly SOC and does not accumulate error with time and current. That is an advantage compared to coulomb counter which suffer from SOC drift caused by current sense error and battery self-discharge. The RT9426 provides complete battery status monitor with interrupt alarm function. It could alert to host processor actively when condition of battery over/under-voltage and over-temperature in charge/discharge. Especially for high C-rate battery charging application, it can measure battery voltage by kelvin sense connection to eliminate the IR drop effect for optimal charging profile and safety. More useful alarm functions are Under SOC alert, SOC Change and battery presence status change. Marking Information   Support System Side Fuel Gauging Battery Fuel Gauge for 1-Series (1sXp) Li-Ion/Li-Polymer Applications State of Charge (SOC) Calculated by VoltaicGaugeTM with Current Sensing (VGCS)  No Accumulation Error on Capacity Calculation Battery SOC, SOH, FCC, TTE and Cycle Count  Report Voltage Measurement : ±7.5mV           Current Measurement : ±1% Battery Temperature Measurement: ±3°C Battery monitor with alert indicator for Voltage, Current, Temperature, SOC and Presence High C-Rate Battery Charging Compliance Low Power Consumption Low-Value Sense Resistor (2.5 to 20m, typical 10m) 12 Pin WDFN Package with 0.4mm Pitch 9 Bump WL-CSP Package with 0.5mm Pitch I2C Controlled Interface Applications  Smartphones  Tablet PC Wearable Device   Digital Still Cameras Digital Video Cameras  Handheld and Portable Applications  Ordering Information RT9426 Package Type QW : WDFN-12L 2.5x4 (W-Type) WSC : WL-CSP-9B 2.29x1.74 (BSC) RT9426GQW 01 : Product Code W : Date Code 01W Lead Plating System G : Green (Halogen Free and Pb Free) (For WDFN-12L 2.5x4 Only) RT9426WSC 71 : Product Code W : Date Code 71W Note : Richtek products are :  RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020.  Copyright © 2019 Richtek Technology Corporation. All rights reserved. DS9426-01 October 2019 Suitable for use in SnPb or Pb-free soldering. is a registered trademark of Richtek Technology Corporation. www.richtek.com 1 RT9426 Pin Configuration (TOP VIEW) A1 A2 ALERT SDA NC VBATG VDD VBATS VPTS VSS 1 2 3 4 5 6 GND 13 12 11 10 9 8 7 ALERT SCL SDA TS CSN CSP WDFN-12L 2.5x4 A3 SCL B1 B2 B3 TS VSS VPTS C1 C2 C3 CSN CSP VBAT WL-CSP-9B 2.29x1.74 (BSC) Simplified Application Circuit For WDFN-12L 2.5x4 Single-Cell Li-ion / Li-Polymer Battery Pack Host System Charger+/VSYSTEM PACK+ RT9426 VDD VBATS VPTS ALERT SCL TS System Processor SDA Protection Module VBATG CSP CSN PACK- Copyright © 2019 Richtek Technology Corporation. All rights reserved. www.richtek.com 2 VSS Charger-/SYSTEM GND is a registered trademark of Richtek Technology Corporation. DS9426-01 October 2019 RT9426 For WL-CSP-9B 2.29x1.74 (BSC) Single-Cell Li-ion / Li-Polymer Battery Pack Host System PACK+ Charger+/VSYSTEM RT9426 VBAT VPTS ALERT SCL System Processor TS T SDA Protection Module VSS CSP PACK- CSN Charger-/SYSTEM GND Functional Pin Description Pin No. WDFN-12L 2.5x4 WL-CSP-9B 2.29x1.74 (BSC) Pin Name 1 -- NC 2 -- VBATG 3 C3 VDD/VBAT Power supply input and battery voltage sensing input for WL-CSP package. 4 -- VBATS Battery voltage sensing positive input. Connect to battery connector with kelvin connection. 5 B3 VPTS Power reference output pin for temperature measurement. 6 B2 VSS Device ground. 7 C2 CSP Battery current sensing positive input. Connect a 10m sense resistor with kelvin connection. 8 C1 CSN Battery current sensing negative input. Connect a 10m sense resistor with kelvin connection. 9 B1 TS 10 A2 SDA Serial data input. Slave I2C serial communications data line for communication with system. Open-drain I/O. 11 A3 SCL Serial cock input. Slave I2C serial communications clock line for communication with system. Open-drain I/O. 12 A1 ALERT Copyright © 2019 Richtek Technology Corporation. All rights reserved. DS9426-01 October 2019 Pin Function No connection. Please keep floating. Battery voltage sensing negative input. Connect to battery connector with kelvin connection. Temperature measurement input. Alert open-drain indicator output. is a registered trademark of Richtek Technology Corporation. www.richtek.com 3 RT9426 Functional Block Diagram VDD VPTS VREF VGCS Engine ALERT Communication TS Voltaic GaugeTM SDA SCL VBATS VBATG ADC CSP Controller Current Sensing Compensation CSN VSS Copyright © 2019 Richtek Technology Corporation. All rights reserved. www.richtek.com 4 is a registered trademark of Richtek Technology Corporation. DS9426-01 October 2019 RT9426 Absolute Maximum Ratings (Note 1)  Voltage on CSN Pin to CSP -------------------------------------------------------------------------------- 0.3V to 2V  Voltage on VBATS, VBATG, VPTS, TS to VSS ------------------------------------------------------- 0.3V to (VDD + 0.3V)  Voltage on VDD Pin Relative to VSS ---------------------------------------------------------------------0.3V to 6V  Voltage on All Other Pins Relative to VSS --------------------------------------------------------------0.3V to 6V  Power Dissipation, PD @ TA = 25C WDFN-12L 2.5x4 ---------------------------------------------------------------------------------------------- 3.25W WL-CSP-9B 2.29x1.74 (BSC) ------------------------------------------------------------------------------ 1.65W  Package Thermal Resistance (Note 2) WDFN-12L 2.5x4, JA ---------------------------------------------------------------------------------------- 30.7C/W WDFN-12L 2.5x4, JC ---------------------------------------------------------------------------------------- 4C/W WL-CSP-9B 2.29x1.74 (BSC), JA ------------------------------------------------------------------------ 60.3C/W  Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------ 260C  Junction Temperature ---------------------------------------------------------------------------------------- 150C  Storage Temperature Range ------------------------------------------------------------------------------- 65C to 150C  ESD Susceptibility (Note 3) HBM (Human Body Model) --------------------------------------------------------------------------------- 2kV Recommended Operating Conditions (Note 4)  Supply Voltage, VDD ---------------------------------------------------------------------------------------- 2.5V to 5.5V  Ambient Temperature Range------------------------------------------------------------------------------ 40C to 85C  Junction Temperature Range ----------------------------------------------------------------------------- 40C to 125C Electrical Characteristics (2.5V  VDD  5.5V, TA = 25C, unless otherwise specified) Parameter Symbol Operation Voltage Test Conditions VDD - VSS Min Typ Max Unit 2.5 -- 5.5 V Active Current IACTIVE Active mode, VDD = 3.8V, BD_PRES_EN = 0 and not including external temp. measurement current. -- 14 20 A Sleep Current ISLEEP Sleep mode, VDD = 3.8V, BD_PRES_EN = 0 and not including external temp. measurement current. -- 5 7 A Shutdown Current ISHUTDOWN VDD = 3.8V -- 0.5 1 A 2.5 -- VDD V VBATS = 4V, VBATG = 0V 7.5 -- 7.5 mV VCSP - VCSN 125 -- 125 mV Voltage Measurement Range Voltage Measurement Error VERR Current Measurement Range Current Measurement Error IERR Current = 1A, RSENSE = 10m 1 -- 1 % Temperature Measurement Error ExtTGERR TA = 25°C 3 -- 3 °C Copyright © 2019 Richtek Technology Corporation. All rights reserved. DS9426-01 October 2019 (Note 5) is a registered trademark of Richtek Technology Corporation. www.richtek.com 5 RT9426 Parameter Symbol Min Typ Max Unit 40 -- 85 °C -- 3 -- °C Input Impedance : VBATS, VBATG, TS 15 -- -- M Input Impedance : CSN, CSP 1 -- -- M Internal Temperature Measurement Range Internal Temperature Measurement Error Test Conditions (Note 6) IntTGERR TA = 25°C Battery Presence Detect Threshold 0.91x 0.94x 0.97x VDD VDD VDD V Battery Presence Detect Pull High Resistor -- 150 -- k Battery Insertion Detection Time -- -- 25 ms Battery Removal Detection Time -- -- 1.1 ms 1.146 1.2 1.254 V VPTS Output Drive IOUT = 0.5mA Input Logic-High : SCL, SDA, ALERT VIH Reference to VSS 1.4 -- -- V Input Logic-Low : SCL, SDA, ALERT VIL Reference to VSS -- -- 0.5 V Output Logic-Low : SDA, ALERT VOL IOL = 3mA (Reference to VSS) -- -- 0.4 V Pulldown Current : SCL, SDA, ALERT IPDN VDD = 4.5V, VSCL, SDA, ALERT = 0.4V 0.05 0.2 0.4 A Min Typ Max Unit 10 -- 400 kHz 1.3 -- -- s 0.6 -- -- s Low Period of the SCL Clock tLOW 1.3 -- -- s High Period of the SCL Clock tHIGH 0.6 -- -- s Setup Time for a Repeated START Condition tSU:STA 0.6 -- -- s Data Hold Time tHD:DAT (Note 8, 9) 0.2 -- 0.9 s Data Setup Time tSU:DAT (Note 8) 100 -- Clock Data Rise Time tR 20 -- 300 ns Clock Data Fall Time tF 20 -- 300 ns Electrical Characteristics : I2C Interface (2.5V  VDD  4.5V, TA = 25C, unless otherwise specified) Parameter Clock Operating Frequency Symbol f SCL Test Conditions (Note 7) Bus Free Time Between a tBUF STOP and START Condition Hold Time After START Condition tHD:STA (Note 7) Copyright © 2019 Richtek Technology Corporation. All rights reserved. www.richtek.com 6 ns is a registered trademark of Richtek Technology Corporation. DS9426-01 October 2019 RT9426 Parameter Symbol Test Conditions Min Typ Max Unit 0.6 -- -- s Set-up Time for STOP Condition tSU:STO Spike Pulse Widths Suppressed by Input Filter tSP (Note 10) 0 -- 50 ns Capacitive Load for Each Bus Line CB (Note 11) -- -- 400 pF SCL, SDA Input Capacitance CBIN -- -- 60 pF Note 1. Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions may affect device reliability. Note 2. JA is measured under natural convection (still air) at TA = 25°C with the component mounted on a high effective-thermal-conductivity four-layer test board on a JEDEC 51-7 thermal measurement standard.JC is measured at the top of the package. Note 3. Devices are ESD sensitive. Handling precaution is recommended. Note 4. The device is not guaranteed to function outside its operating conditions. Note 5. The thermistor is use 10k NTC and beta 3435k, default is SEMITEC 103KT1608T. Note 6. Specifications are 100% tested at TA = 25°C. Limits over the operating range are guaranteed by design and characterization. Note 7. fSCL must meet the minimum clock low time plus the rise/fall times. Note 8. The maximum tHD:DAT has only to be met if the device does not stretch the low period (t LOW ) of the SCL signal. Note 9. This device internally provides a hold time of at least 75ns for the SDA signal (referred to the VIHMIN) of the SCL signal) to bridge the undefined region of the falling edge of SCL. Note 10. Filters on SDA and SCL suppress noise spikes at the input buffers and delay the sampling instant. Note 11. CB – total capacitance of one bus line in pF. I2C Timing Diagram SDA tF tSU:DAT tSP tF tR tLOW tBUF tR tHD:STA SCL tHD:STA S tSU:STA tHD:DAT Copyright © 2019 Richtek Technology Corporation. All rights reserved. DS9426-01 October 2019 tSU:STO Sr P S is a registered trademark of Richtek Technology Corporation. www.richtek.com 7 RT9426 Typical Application Circuit For WDFN-12L 2.5x4 Charger+ / VSYSTEM C2 0.1µF PACK+ IO Power 3 VDD RT9426 + 4 VBATS ALERT 5 C3 10nF NTC VPTS SCL C1 1µF 9 Battery Protection Module 2 TS SDA VBATG VSS R1 10kΩ (optional) CSP 12 SYSTEM Processor 11 10 6 CSN RS 10mΩ PACK- Charger- / SYSTEM GND For WL-CSP-9B 2.29x1.74 (BSC) (optional high-side sensing) Charger+ / VSYSTEM RS 10mΩ PACK+ + Removeable Battery Peak IO Power RT9426 C2 CSP C1 C3 CSN ALERT VBAT SDA Battery Protection Module B3 T R1 10kΩ (optional) VPTS SCL C1 1µF C2 10nF NTC B1 B2 A1 SYSTEM Processor A2 A3 TS VSS CSP CSN C2 C1 Charger- / SYSTEM GND PACK- RS 10mΩ * Both WL-CSP and WDFN can option High/Low Side NTC Copyright © 2019 Richtek Technology Corporation. All rights reserved. www.richtek.com 8 is a registered trademark of Richtek Technology Corporation. DS9426-01 October 2019 RT9426 Typical Operating Characteristics * : Sample accuracy with custom parameter into the IC. Voltage ADC Error vs. Temperature Current ADC Error vs. Temperature 10 10 40C 8 6 Current ADC Error (mA) 85C 4 2 0 25C -2 -4 -6 -8 40C 6 4 2 85C 0 25C -2 -4 -6 -8 -10 -2000 -1500 -1000 -500 4500 4300 4100 3900 3700 3500 3300 3100 2900 2700 2500 -10 500 1000 1500 2000 Current (mA) Voltage (mV) Temperature Measurement Error vs. Temperature SOC Accuracy* 5 100 4 90 3 80 2 70 1 SOC (%) Temperature Measurement Error (°C)1 0 0 -1 -2 SOC_VGCS Reference_SOC SOC_Error_VGCS -3 -4 4 C/4 DCHG 60 2 50 0 C/4 CHG 40 -2 C/2 CHG 20 -4 -6 1.5C CHG C/2 DCHG 10 -5 -8 0 -40 -20 0 20 25 45 65 Temperature (°C) Copyright © 2019 Richtek Technology Corporation. All rights reserved. DS9426-01 October 2019 8 6 30 VDD = 2.5V VDD = 3.5V VDD = 4.5V 10 SOC Error (%) Voltage ADC Error (mV) 8 85 -10 0 1 2 3 4 5 6 7 8 9 10 Time (h) is a registered trademark of Richtek Technology Corporation. www.richtek.com 9 RT9426 Application Information The RT9426 reports temperature to Temperature register by measuring battery temperature or chip ADC for Voltage, Current and Temperature Battery voltage is measured at the VBATS pin input with respect to VBATG over a 2.5 to 5.5V range with resolutions of 1mV. The ADC calculates the first cell voltage for a period of 250ms after IC POR and then for a period of 1s for every cycle afterwards. The Voltage temperature. When measuring battery temperature, an external NTC resistor will be used. register requires 1s to update after exiting Sleep mode. The result is placed in the Voltage register at the end of each conversion period. The VGCS algorithm is based on the battery voltage and the dynamic difference of battery voltage and battery current measurement, by iterating battery voltage information and compensating with current information to increase or decrease delta SOC, then The RT9426 Fuel Gauge measures battery current in charging and discharging and reports it to Current register. The measurement range is 10A (RS = 10m), and the resolution is 1mA. Input VoltaicGauge™ with Current Sensing (VGCS) Algorithm integrate to SOC. The below figure is for VGCS functional block. VGCS Algorithm OCV Table Lookup Output StateOfCharge StateOfHealth Voltage TM VoltaicGauge with Current Sensing Current FullChargeCapacity CycleCount Temperature Battery Capacity Compensation TimetoEmpty DesignCapacity The RT9426 got battery voltage information then using Design Capacity OCV table and iterate calculation with current correction to calculate delta SOC, then using design capacity and battery capacity as a reference to optimize result and output final SOC result. VGCS also support high C-RATE charging technology. The DesignCapacity register should be set with proper value after IC POR, Design Capacity is the expected capacity when cell has been made and it’s not been changed when VGCS active. Design Capacity is used as a reference input for VGCS algorithm. The The coulomb counter based fuel gauge suffers from SOC drift due to current-sense error and cell self-discharge. Even there is a very small current sensing error, the coulomb counter accumulates the error from time to time, VGCS is based on voltage resolution of Design Capacity is 1mAh and default value is 0x07D0 (2000mAh). iteration algorithm to reach stable SOC behavior and only using current information to fine tune result for getting good transient state response. VGCS does not accumulate current and suffer SOC drift issue like traditional coulomb counter. displays the state of charge of the cell as calculated by the VGCS algorithm. The result is displayed as a percentage of the cell’s full capacity. This register automatically adapts to variation in battery size since the Fuel Gauge naturally recognize relative SOC. The Copyright © 2019 Richtek Technology Corporation. All rights reserved. www.richtek.com 10 SOC Report The StateOfCharge register is a read-only register that is a registered trademark of Richtek Technology Corporation. DS9426-01 October 2019 RT9426 units of SOC is %. The reported SOC also includes residual capacity, which might not be available to the actual application because of early termination voltage Power Mode Switching POR requirements. When SOC = 0, typical applications have no remaining capacity. The first update occurs in 250ms after POR of the IC. Active 1. Exit shutdown command 2 2. I C pull high Power Mode There are three power mode for the RT9426. Each power mode could be applied on different application for different power consumption considering. The three power modes are Active mode, Sleep mode and Shutdown mode. Disable Sleep Mode & 1. Exit sleep command or 2. FG self-detected exit Enable Shutdown Mode & 1. Entry shutdown command or 2 2. SHDN_LOW_EN = 1 & I C pull low Shutdown Enable Sleep Mode & 1. Entry sleep command or 2. FG self-detected entry Sleep 1. Exit shutdown command 2 2. I C pull high *: Exit shutdown or sleep mode method must be follow as entry method last time. Ex: Entry sleep mode by command, it must also use command to exit sleep mode. Active Mode The active mode is recommended and it is the default power mode after POR. In active mode, the Voltage, Current, Temperature, AverageVoltage, AverageCurrent and AverageTemperature will be Controller updated every second. The controller takes care of the control flow of system routine, ADC measurement flow, algorithm calculation and alert determined. Sleep Mode Power Up Sequence The sleep mode behavior is same as the active mode but it has the longer measurement period. The period in When the RT9426 is power on, the Fuel Gauge (FG) measures the battery voltage and then predicts the first SOC according to the voltage for a period of 250ms. the sleep mode is programmable. The minimum period is 2 times of active mode and the maximum period is 16 times of active mode. The default period is 4 times of active mode. When sleep mode function is enabled, it could be entered/exited by sending commands or by Fuel Gauge self-detection. The first SOC would be accurate if the battery has been well relaxed for over 30 minutes. Otherwise, the initial SOC error occurs. However, the initial SOC error will be convergent and the SOC will be adjusted gradually and finally approach to the OCV when battery is relaxed. Shutdown Mode In shutdown mode, the RT9426 will stop all measurement behaviors and stop to update registers to keep the minimum power consumption. To enter shutdown mode, the function should be enabled first. Then, it could be entered by either sending command or pulling low I2C bus. To exit shutdown mode, an exit shutdown command should be received when it’s entered by command. Otherwise, the I2C bus should be pulled high when it’s entered by I2C bus low condition. Copyright © 2019 Richtek Technology Corporation. All rights reserved. DS9426-01 October 2019 Quick Sensing A Quick Sensing operation allows the RT9426 to restart battery voltage sensing and StateOfCharge calculation. The operation is used to reduce the initial StateOfCharge error caused by improper power-on sequence. A Quick Sensing operation could be performed by I2C Quick Sensing command (0x4000) to the Control register. is a registered trademark of Richtek Technology Corporation. www.richtek.com 11 RT9426 Host can polling the ALERT Flag for a period to monitor system status or accept the interrupt notice from the RT9426 ALERT pin. Alert need to be enabled before it Alert Function The RT9426 support several kinds of alert to alarm system there is abnormal condition need to be noticed, such as over temperature or under voltage. It total includes over-temperature in charge (OTC), over-temperature in discharge (OTD), over-voltage (OV), under-voltage (UV), under-SOC (US) and SOC change (SC). 1 2 3 works. There are 2 ways to enable alert function. One is to enable specified bit operation, the other is just to set a proper value to detection threshold. Please refer to below diagram and descriptions for detailed. 4 5 6 7 8 OV / UV / OTC / OTD / US ALERT Condition ALERT_EN e.g. OV_DET ALERT FLAG e.g. OV IRQ_EN e.g. VOL_IRQ_EN IRQ ALERT PIN Host Communication Figure 1. ALERT Function Timing Diagram 1. ALERT occur but ALERT_EN is disabled, ALERT FLAG have no response. 2. ALERT_EN enable, ALERT FLAG is set when ALERT condition occur. 3. ALERT FLAG is cleared when ALERT condition recover. 4. When ALERT FLAG is already set and IRQ_EN is set, IRQ and ALERT PIN output have no response. 5. IRQ is set and ALERT PIN output low only when IRQ_EN is set and ALERT FLAG state change. 6. IRQ and ALERT PIN are read clear only. 7. Clear IRQ_EN have no effect on IRQ and ALERT PIN output. 8. Disable ALERT_EN will also clear ALERT FLAG. Copyright © 2019 Richtek Technology Corporation. All rights reserved. www.richtek.com 12 is a registered trademark of Richtek Technology Corporation. DS9426-01 October 2019 RT9426 1 2 3 4 5 6 7 8 SC ALERT Condition ALERT_EN e.g. SC_EN ALERT FLAG e.g. SC IRQ_EN e.g. SOC_IRQ_EN IRQ ALERT PIN W Host Communication W R R Figure 2. SC ALERT Function Timing Diagram 1. ALERT condition occur but ALERT_EN disable, ALERT FLAG have no response 2. ALERT_EN enable, ALERT FLAG is set when ALERT condition occur. 3. ALERT FLAG is cleared when driver write ALERT_FLAG to 0. 4. When ALERT_FLAG is already set and IRQ_EN is set, IRQ and ALERT PIN output have no response. 5. IRQ is set and ALERT PIN output low only when IRQ_EN is set and ALERT FLAG state set. 6. IRQ and ALERT PIN are read clear only, driver read clear IRQ will also clear ALERT FLAG 7. Clear IRQ_EN have no effect on IRQ and ALERT PIN output. 8. Disable ALERT_EN will also clear ALERT_FLAG. Copyright © 2019 Richtek Technology Corporation. All rights reserved. DS9426-01 October 2019 is a registered trademark of Richtek Technology Corporation. www.richtek.com 13 RT9426 I2C Interface The RT9426 I2C slave address = 7’b1010101. I2C interface support fast mode (bit rate up to 400kb/s). The write or read bit stream is shown below : Read data from the RT9426 Slave Address Register Address S 0 A R/W Slave Address MSB A Sr 1 Data 2 LSB A Assume Address = m MSB Data 1 A Data for Address = m LSB A P Data for Address = m + 1 Write data to the RT9426 Slave Address Register Address S 0 R/W Driven by Master, A MSB Data 1 A P Stop, MSB Data 2 LSB A Assume Address = m Driven by Slave (RT9426), LSB Data for Address = m S Start, A P Data for Address = m + 1 Sr Repeat Start Register Summary Table Name Symbol Address Unit Mode Reset Control CNTL 0x00 to 0x01 -- R/W 0x0000 Current CURR 0x04 to 0x05 mA R 0x0000 Temperature TEMP 0x06 to 0x07 0.1°K R/W 0x0BA6 Voltage VBAT 0x08 to 0x09 mV R 0x0ED8 Flag1 FLAG1 0x0A to 0x0B -- R 0x0000 Flag2 FLAG2 0x0C to 0x0D -- R 0x0000 RemainingCapacity RM 0x10 to 0x11 mAh R 0x03CF FullChargeCapacity FCC 0x12 to 0x13 mAh R 0x07D0 AverageCurrent AI 0x14 to 0x15 mA R 0x0000 TimeToEmpty TTE 0x16 to 0x17 minute R 0xFFFF Version VER 0x20 to 0x21 -- R 0x0001 VGCOMP12 VGCOMP12 0x24 to 0x25 -- R/W 0x3232 VGCOMP34 VGCOMP34 0x26 to 0x27 -- R/W 0x3232 InternalTemerature INTT 0x28 to 0x29 0.1°K R 0x0BA6 CycleCount CYC 0x2A to 0x2B Counts R/W 0x0000 StateOfCharge SOC 0x2C to 0x2D % R 0x0032 StateOfHealth SOH 0x2E to 0x2F % R 0x0064 Flag3 FLAG3 0x30 to 0x31 -- R 0x0000 IRQ IRQ 0x36 to 0x37 -- R 0x0000 DesignCapacity DC 0x3C to 0x3D mAh R 0x07D0 ExtendedControl EXTDCNTL 0x3E to 0x3F -- W 0x0000 AverageVoltage AV 0x64 to 0x65 mV R 0x0ED8 AverageTemperature AT 0x66 to 0x67 0.1°K R 0x0BA6 Copyright © 2019 Richtek Technology Corporation. All rights reserved. www.richtek.com 14 is a registered trademark of Richtek Technology Corporation. DS9426-01 October 2019 RT9426 Thermal Considerations absolute maximum junction temperature TJ(MAX), listed under Absolute Maximum Ratings, to avoid permanent damage to the device. The maximum allowable power dissipation depends on the thermal resistance of the IC package, the PCB layout, the rate of surrounding airflow, and the difference between the junction and ambient temperatures. The maximum power dissipation can be calculated using the following formula : PD(MAX) = (TJ(MAX) - TA) / JA where TJ(MAX) is the maximum junction temperature, TA is the ambient temperature, and JA is the junction-to-ambient thermal resistance. For continuous operation, the maximum operating junction temperature indicated under Recommended Operating Conditions is 125°C. The junction-to-ambient thermal resistance, JA, is highly package dependent. For a WDFN-12L 2.5x4 package, the thermal resistance, JA, is 30.7°C/W on a standard JEDEC 51-7 high effective-thermal-conductivity four-layer test board. For a WL-CSP-9B 2.29x1.74 (BSC) package, the thermal resistance, JA, is 30.6°C/W on a standard JEDEC 51-7 high effective-thermal-conductivity four-layer test board. The maximum power dissipation at TA = 25°C can be calculated as below : PD(MAX) = (125°C - 25°C) / (30.7°C/W) = 3.25W for a WDFN-12L 2.5x4 package. PD(MAX) = (125°C - 25°C) / (60.3°C/W) = 1.65W for a Maximum Power Dissipation (W)1 The junction temperature should never exceed the 3.5 Four-Layer PCB 3.0 WDFN-12L 2.5x4 2.5 2.0 1.5 1.0 WL-CSP-9B 2.29x1.74 (BSC) 0.5 0.0 0 25 50 75 100 125 Ambient Temperature (°C) Figure 3. Derating Curve of Maximum Power Dissipation Layout Considerations To ensure the measurement accuracy of the RT9426, the recommended layout guideline is as below : ▶ The capacitor of VBATS and VDD pins must be put as close as possible to avoid the noise effect. ▶ The VBATS and VBATG path must be make Kelvin Sense connection to the P+ and P- to minimize the IR drop effect on voltage measurement accuracy. ▶ The CSN and CSP path must be make Kelvin Sense connection to RS to avoid the IR drop effect on current measurement accuracy. ▶ The NTC should be as close as possible to the Battery and far away from the thermal area. ▶ There are no special layout requirements for other pins. WL-CSP-9B 2.29x1.74 (BSC) package. The maximum power dissipation depends on the operating ambient temperature for the fixed TJ(MAX) and the thermal resistance, JA. The derating curves in Figure 3 allows the designer to see the effect of rising ambient temperature on the maximum power dissipation. Copyright © 2019 Richtek Technology Corporation. All rights reserved. DS9426-01 October 2019 is a registered trademark of Richtek Technology Corporation. www.richtek.com 15 RT9426 Positive Power Bus P+ Place the chip as close as possible to the battery Top Layer C2 Bottom Layer C1 ALERT 12 1 NC 2 VBATG SCL 11 3 VDD SDA 10 4 VBATS 5 VPTS CSN 8 6 VSS CSP 7 TS C3 NTC 9 Mount the RS as close as possible to P- and using kelvin sense layout style to avoid IR drop Capacitor must be placed as close as possible to the input pins SGND (System GND) PRS Negative Power Bus Figure 4. PCB Layout Guide for WDFN-12L 2.5x4 Package Positive Power Bus P+ Top Layer Bottom Layer A3 SCL B3 VPTS C3 VBAT A2 SDA B2 VSS C2 CSP A1 ALERT B1 TS C1 CSN Place the capacitor as close as possible to the pin C1 Mount the RS as close as possible to P- and using kelvin sense layout style to avoid IR drop Negative Power Bus SGND NTC C2 RS P- (System GND) Figure 5. Low-Side Sensing PCB Layout Guide for WL-CSP-9B 2.29x1.74 (BSC) Package Copyright © 2019 Richtek Technology Corporation. All rights reserved. www.richtek.com 16 is a registered trademark of Richtek Technology Corporation. DS9426-01 October 2019 RT9426 RS Positive Power Bus P+ Mount the RS as close as possible to P+ and using kelvin sense layout style to avoid IR drop Top Layer Bottom Layer Place the capacitor as close as possible to the pin C1 Negative Power Bus C3 C2 C1 VBATS CSP CSN B3 B2 B1 VPTS VSS TS A3 A2 A1 SCL SDA ALERT C2 NTC SGND P- (System GND) Figure 6. High-Side Sensing PCB Layout Guide for WL-CSP-9B 2.29x1.74 (BSC) Package Copyright © 2019 Richtek Technology Corporation. All rights reserved. DS9426-01 October 2019 is a registered trademark of Richtek Technology Corporation. www.richtek.com 17 RT9426 Outline Dimension Symbol Dimensions In Millimeters Dimensions In Inches Min Max Min Max A 0.700 0.800 0.028 0.031 A1 0.000 0.050 0.000 0.002 A3 0.175 0.250 0.007 0.010 b 0.150 0.250 0.006 0.010 D 2.400 2.600 0.094 0.102 D2 1.950 2.050 0.077 0.081 E 3.900 4.100 0.154 0.161 E2 2.450 2.550 0.096 0.100 e L 0.400 0.350 0.016 0.450 0.014 0.018 W-Type 12L DFN 2.5x4 Package Copyright © 2019 Richtek Technology Corporation. All rights reserved. www.richtek.com 18 is a registered trademark of Richtek Technology Corporation. DS9426-01 October 2019 RT9426 Dimensions In Millimeters Symbol Dimensions In Inches Min Max Min Max A 0.525 0.625 0.021 0.025 A1 0.200 0.260 0.008 0.010 b 0.290 0.350 0.011 0.014 D 1.700 1.780 0.067 0.070 D1 1.000 E 2.250 0.039 2.330 0.089 0.092 E1 1.000 0.039 e 0.500 0.020 9B WL-CSP 2.29x1.74 Package (BSC) Copyright © 2019 Richtek Technology Corporation. All rights reserved. DS9426-01 October 2019 is a registered trademark of Richtek Technology Corporation. www.richtek.com 19 RT9426 Footprint Information Package V/W/U/XDFN2.5x4-12 Footprint Dimension (mm) Number of P A B C D Sx Sy M 12 0.40 4.80 3.10 0.85 0.20 2.50 2.50 2.20 Copyright © 2019 Richtek Technology Corporation. All rights reserved. www.richtek.com 20 Tolerance Pin ±0.05 is a registered trademark of Richtek Technology Corporation. DS9426-01 October 2019 RT9426 Number of Package Pin Type Footprint Dimension (mm) e NSMD WL-CSP2.29x1.74-9(BSC) 9 SMD 0.500 A B 0.275 0.375 0.375 0.275 Tolerance ±0.025 Richtek Technology Corporation 14F, No. 8, Tai Yuen 1st Street, Chupei City Hsinchu, Taiwan, R.O.C. Tel: (8863)5526789 Richtek products are sold by description only. Richtek reserves the right to change the circuitry and/or specifications without notice at any time. Customers should obtain the latest relevant information and data sheets before placing orders and should verify that such information is current and complete. Richtek cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Richtek product. Information furnished by Richtek is believed to be accurate and reliable. However, no responsibility is assumed by Richtek or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Richtek or its subsidiaries. Copyright © 2019 Richtek Technology Corporation. All rights reserved. DS9426-01 October 2019 is a registered trademark of Richtek Technology Corporation. www.richtek.com 21