SMBus Level 2 Battery Charger

www.DataSheet4U.com 19-3923; Rev 0; 1/06 KIT ATION EVALU ILABLE AVA SMBus Level 2 Battery Charger with Remote Sense General Description The MAX8731 is an SMBus™ programmable multichemistry battery charger. The MAX8731 uses a minimal command set to easily program the charge voltage, charge current, and adapter current limit. The MAX8731 charges one to four Li+ series cells and delivers up to 8A charge current. The MAX8731 drives n-channel MOSFETs for improved efficiency and reduced cost. Low-offset current-sense amplifiers provide high accuracy with 10mΩ sense resistors. The MAX8731 current-sense amplifiers provide high accuracy (3% at 3.5A) and also provide fast cycle-bycycle current-mode control to protect against battery short circuit and system load transients. The charger employs dual remote-sense, which reduces charge time by measuring the feedback voltage directly at the battery, improving accuracy of initial transition into constant-voltage mode. The MAX8731 provides 0.5% battery voltage accuracy directly at the battery terminal. The MAX8731 provides a digital output that indicates the presence of the AC adapter, as well as an analog output that indicates the adapter current within 4% accuracy. The MAX8731 is available in a small 5mm x 5mm, 28-pin, thin (0.8mm) QFN package. An evaluation kit is available to reduce design time. The MAX8731 is available in lead-free packages. SMBus is a trademark of Intel Corp. Features ♦ ♦ ♦ ♦ ♦ 0.5% Battery Voltage Accuracy 3% Input Current-Limit Accuracy 3% Charge-Current Accuracy SMBus 2-Wire Serial Interface Cycle-by-Cycle Current Limit Battery Short-Circuit Protection Fast Response for Pulse Charging Fast System-Load-Transient Response Dual-Remote-Sense Inputs Monitor Outputs for Adapter Current (4% Accuracy) AC Adapter Detection 11-Bit Battery Voltage Setting 6-Bit Charge-Current/Input-Current Setting 8A (max) Battery Charger Current 11A (max) Input Current +8V to +26V Input Voltage Range Charges Li+, NiMH, and NiCd Battery Chemistries MAX8731 ♦ ♦ ♦ ♦ ♦ ♦ ♦ ♦ Ordering Information PART TEMP RANGE PIN-PACKAGE 28 Thin QFN (5mm x 5mm) MAX8731ETI+ -40°C to +85°C +Indicates lead-free packaging. Applications Notebook Computers Tablet PCs Medical Devices Portable Equipment with Rechargeable Batteries Typical Operating Circuit EXTERNAL LOAD OPTIONAL CSSP CSSN DHI LX Pin Configuration PGND FBSB FBSA CSIN CSIP LDO DLO N TOP VIEW ACIN DCIN ACOK MAX8731 DLO REF PGND BST CSIP CSIN N 21 DCIN 22 LX 23 DHI 24 BST 25 VCC 26 CSSN 27 CSSP 28 1 GND 20 19 18 17 16 15 14 13 12 BATSEL ACOK GND VDD SCL SDA IINP HOST SCL SDA VDD GND SELECTOR FBSA BATSEL SCL SDA VDD GND IINP DAC CCS LDO VCC CCV CCI FBSB BATSEL BATTERY A MAX8731 11 10 *EXPOSED PADDLE 9 8 BATTERY B 2 ACIN 3 REF 4 CCS 5 CCI 6 CCV 7 DAC THIN QFN 5mm x 5mm ________________________________________________________________ Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. SMBus Level 2 Battery Charger with Remote Sense MAX8731 ABSOLUTE MAXIMUM RATINGS DCIN, CSSN, CSIN, FBSA, FBSB to GND..............-0.3V to +28V CSSP to CSSN, CSIP to CSIN, PGND to GND ......-0.3V to +0.3V BST to GND ............................................................-0.3V to +32V BST to LX..................................................................-0.3V to +6V DHI to LX.................................................-0.3V to +(VBST + 0.3)V DLO to PGND..........................................-0.3V to +(LDO + 0.3)V LX to GND .................................................................-6V to +28V CCI, CCS, CCV, DAC, REF, IINP to GND...........................................-0.3V to (VVCC + 0.3)V VDD, SCL, SDA, BATSEL, ACIN, ACOK, VCC to GND, LDO to PGND ......................................................-0.3V to +6V Continuous Power Dissipation (TA = +70°C) 28-Pin Thin QFN (derate 20.8mW/°C above +70°C) ........................1666.7 mW Operating Temperature Range ...........................-40°C to +85°C Junction Temperature ......................................................+150°C Storage Temperature Range .............................-60°C to +150°C Lead Temperature (soldering, 10s) .................................+300°C 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 for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS (VDCIN = VLX = VCSSP = VCSSN = 19V, VBST - VLX = 4.5V, VFBSA = VFBSB = VCSIP = VCSIN = 16.8V, BATSEL = GND = PGND = 0, CLDO = 1µF, VCC = LDO, CREF = 1µF, CDAC = 0.1µF, VDD = 3.3V, ACIN = 2.5V; pins CCI, CCV, and CCS are compensated per Figure 1; TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER CHARGE-VOLTAGE REGULATION ChargingVoltage() = 0x41A0 ChargingVoltage() = 0x3130 Battery Full-Charge Voltage and Accuracy ChargingVoltage() = 0x20D0 ChargingVoltage() = 0x1060 Battery Undervoltage-Lockout Trip Point for Trickle Charge CHARGE-CURRENT REGULATION CSIP to CSIN Full-Scale CurrentSense Voltage RS2 (Figure 1) = 10mΩ; ChargingCurrent() = 0x1f80 Charge Current and Accuracy RS2 (Figure 1) = 10mΩ; ChargingCurrent() = 0x0f80 RS2 (Figure 1) = 10mΩ; ChargingCurrent() = 0x0080 (128mA) Charge-Current Gain Error FBSA/FBSB/CSIP/CSIN Input Voltage Range Based on ChargeCurrent() = 128mA and 8.064A 78.22 7.822 -3 3.809 -4 64 -2 0 3.968 80.64 8.064 83.06 8.306 +3 4.126 +4 400 +2 19 mV A % A % mA % V 16.716 -0.5 12.491 -0.8 8.333 -0.8 4.15 -1.0 2.5 4.192 8.4 12.592 16.8 16.884 +0.5 12.693 +0.8 8.467 +0.8 4.234 +1.0 V % V % V % V % V CONDITIONS MIN TYP MAX UNITS 2 _______________________________________________________________________________________ SMBus Level 2 Battery Charger with Remote Sense ELECTRICAL CHARACTERISTICS (continued) (VDCIN = VLX = VCSSP = VCSSN = 19V, VBST - VLX = 4.5V, VFBSA = VFBSB = VCSIP = VCSIN = 16.8V, BATSEL = GND = PGND = 0, CLDO = 1µF, VCC = LDO, CREF = 1µF, CDAC = 0.1µF, VDD = 3.3V, ACIN = 2.5V; pins CCI, CCV, and CCS are compensated per Figure 1; TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER CONDITIONS Adapter present, not charging, ICSIP + ICSIN + ILX + IFBS, VFBS_ = VLX = VCSIN = VCSIP = 19V Adapter absent, ICSIP + ICSIN + ILX + IFBSA + IFBSB + ICSSP + ICSSN, VFBS_ = VLX = VCSIN = VCSIP = 19V, VDCIN = 0V VAdapter = 26V, VBattery = 16.8V, not charging Adapter Quiescent Current IDCIN + ICSSP + ICSSN VAdapter = 19V, VBattery = 16.8V VAdapter = 8V, VBattery = 4V INPUT-CURRENT REGULATION CSSP to CSSN Full-Scale Current-Sense Voltage Input Current Accuracy POR Input Current Input Current-Limit Gain Error Input Current-Limit Offset CSSP/CSSN Input Voltage Range IINP Transconductance IINP Offset IINP Accuracy IINP Output Voltage Range SUPPLY AND LINEAR REGULATOR DCIN, Input Voltage Range DCIN Undervoltage-Lockout Trip Point Power-Fail Threshold DCIN falling DCIN rising VCSSP - VCSIN falling VCSSP - VCSIN rising 9 160 8.0 7 7.4 7.5 15 210 7.85 21 271 26.0 V V mV VCSSP - CSSN = 110mV Based on VCSSP - CSSN = 110mV and 20mV VCSSP - CSSN = 110mV VCSSP - CSSN = 55mV or 35mV VCSSP - CSSN = 20mV VFBS_ = 19V RS1 (Figure 1) = 10mΩ, InputCurrent() = 11004mA or 3584mA RS1 (Figure 1) = 10mΩ, InputCurrent() = 2048mA RS1 (Figure 1) = 10mΩ Based on InputCurrent() = 1024mA and 11004mA -2 -1 8 2.85 -1.5 -5 -4 -10 0 3.0 106.7 -3 -5 256 +2 +1 26 3.15 +1.5 +5 +4 +10 3.5 V % 110 113.3 +3 +5 mV % % mA % mV V mA/V mV Charging Not charging Charging Not charging 200 0.4 200 0.4 200 MIN TYP 2 MAX 5 µA +1 500 1 500 1 500 µA mA µA mA µA UNITS MAX8731 Battery Quiescent Current _______________________________________________________________________________________ 3 SMBus Level 2 Battery Charger with Remote Sense MAX8731 ELECTRICAL CHARACTERISTICS (continued) (VDCIN = VLX = VCSSP = VCSSN = 19V, VBST - VLX = 4.5V, VFBSA = VFBSB = VCSIP = VCSIN = 16.8V, BATSEL = GND = PGND = 0, CLDO = 1µF, VCC = LDO, CREF = 1µF, CDAC = 0.1µF, VDD = 3.3V, ACIN = 2.5V; pins CCI, CCV, and CCS are compensated per Figure 1; TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER LDO Output Voltage LDO Load Regulation LDO Undervoltage-Lockout Threshold VDD Range VDD UVLO Rising VDD UVLO Hysteresis VDD Quiescent Current REFERENCE REF Output Voltage REF Undervoltage-Lockout Trip Point ACOK ACOK Sink Current ACOK Leakage Current ACIN ACIN Threshold ACIN Threshold Hysteresis ACIN Input Bias Current REMOTE-SENSE INPUTS FBS_ Range FBS_ Gain CSIN-FBS_ Clamp Voltage FBS_ Bias Current FBS_ Bias Current SWITCHING REGULATOR Off-Time BST Supply Current LX Input Bias Current Maximum Discontinuous-Mode Peak Current (IMIN) DHI On-Resistance Low DHI On-Resistance High DLO On-Resistance High DLO On-Resistance Low IDHI = -10mA IDHI = 10mA IDLO = 10mA IDLO = -10mA VCSIN = 16.0V, VCSSP = 19V VCSIN = 16.0V, VCSSP = 17V DHI high VDCIN = 28V, VCSIN = VLX = 20V, DHI low 0.5 1 3 3 1 3 5 5 3 360 260 400 300 500 440 360 800 2 ns µA µA A Ω Ω Ω Ω Charger switching, FBS_ selected Charger not switching or FBS_ not selected -2 VCSIN - VFBS ∆VCSIN / ∆(VCSIN - VFBS_) 0 0.95 225 1.00 250 200 1.05 275 14 +2 mV V/V mV µA µA 2.007 10 -1 2.048 20 2.089 30 +1 V mV µA VACOK = 0.4V, ACIN = 1.5V VACOK = 5.5V, ACIN = 2.5V 1 1 mA µA 0 < IREF < 500µA REF falling 4.071 4.096 3.1 4.120 3.9 V V DCIN < 6V, VDD = 5.5V, SCL = SDA = 5.5V 0 < ILDO < 30mA VDCIN = 8.0V, VLDO falling 3.20 2.7 2.5 100 16 27 CONDITIONS 8.0V < VDCIN < 28V, no load MIN 5.25 TYP 5.4 34 4 MAX 5.55 100 5.15 5.5 2.7 UNITS V mV V V V mV µA 4 ____