LTM8062 32VIN, 2A µModule Power Tracking Battery Charger FEATURES n n n n n n n n n DESCRIPTION Complete Battery Charger System Input Supply Voltage Regulation Loop for Peak Power Tracking in MPPT (Maximum Peak Power Tracking) Solar Applications Wide Input Voltage Range: 4.95V to 32V (40V Abs Max) 2A Charge Current Resistor Programmable Float Voltage Up to 14.4V Accommodates Li-Ion/Polymer, LiFePO4, SLA Integrated Input Reverse Voltage Protection User Selectable Termination: C/10 or Termination Timer 0.75% Float Voltage Reference Accuracy 9mm × 15mm × 4.32mm LGA Package n n n The LTM8062 employs an input voltage regulation loop, which reduces charge current if the input voltage falls below a programmed level, set with a resistor divider. When the LTM8062 is powered by a solar panel, this input regulation loop is used to maintain the panel at peak output power. The LTM8062 also features preconditioning trickle charge, bad battery detection, a choice of termination schemes and automatic restart. The LTM8062 is packaged in a thermally enhanced, compact (9mm × 15mm × 4.32mm) over-molded land grid array (LGA) package suitable for automated assembly by standard surface mount equipment. The LTM8062 is RoHS compliant. APPLICATIONS n The LTM®8062 is a complete 32VIN, 2A μModule® power tracking battery charger. The LTM8062 provides a constant-current/constant-voltage charge characteristic, a 2A maximum charge current, and employs a 3.3V float voltage feedback reference, so any desired battery float voltage up to 14.4V can be programmed with a resistor divider. Industrial Handheld Instruments 12V to 24V Automotive and Heavy Equipment Desktop Cradle Chargers Solar Power Battery Charging L, LT, LTC, LTM, Linear Technology, the Linear logo and μModule are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. TYPICAL APPLICATION 2A LiFePO4 μModule Battery Charger Charge Current vs Battery Voltage 2500 VINA LTM8062 VIN 4.7μF BAT BIAS VINREG CHRG RUN FAULT TMR ADJ NTC 274k 2.87M GND 1-CELL LiFePO4 (3.6V) CHARGING CURRENT (mA) VIN 6V TO 32V NORMAL CHARGING 2000 1500 1000 500 PRECONDITION 8062 TA01a TERMINATION 0 0 1 3 2 BATTERY VOLTAGE (V) 4 8062 TA01b 8062f 1 LTM8062 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) VINA, VIN ...................................................................40V VINREG, RUN, CHRG, FAULT ......................VIN + 0.5, 40V TMR, NTC ................................................................2.5V BAT ...........................................................................15V BIAS ..........................................................................10V ADJ .............................................................................5V Maximum Internal Operating Temperature (Note 2)................................................................. 125°C Maximum Body Solder Temperature..................... 245°C TOP VIEW BIAS ADJ FAULT CHRG GND 7 BAT NTC TMR RUN VINREG BANK 2 6 5 VINA BANK 3 4 BANK 1 3 GND BANK 4 2 VIN 1 A B C D E F G H J K L LGA PACKAGE 77-LEAD (15mm s 9mm s 4.32mm) TJMAX = 125°C, θJA = 17.0°C/W, θJCbottom = 6.1°C/W, θJCtop = 16.2°C/W, θJB = 11.2°C/W, WEIGHT = 1.7g θ VALUES DETERMINED PER JEDEC 51-9, 51-12 ORDER INFORMATION LEAD FREE FINISH TRAY PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTM8062EV#PBF LTM8062EV#PBF LTM8062V 77-Lead (15mm × 9mm × 4.32mm) LGA –40°C to 125°C LTM8062IV#PBF LTM8062IV#PBF LTM8062V 77-Lead (15mm × 9mm × 4.32mm) LGA –40°C to 125°C Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ This product is only offered in trays. For more information go to: http://www.linear.com/packaging/ 8062f 2 LTM8062 ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full internal operating temperature range, otherwise specifications are at TA = 25°C. RUN = 2V. PARAMETER CONDITIONS MIN TYP VIN Maximum Operating Voltage 32 l VIN Start Voltage VIN OVLO Threshold VIN Rising 7.5 32 VIN OVLO Hysteresis VIN UVLO Threshold VIN Rising VIN UVLO Hysteresis VINA to VIN Diode Forward Voltage Drop VINA Current = 2A Maximum BAT Float Voltage IBAT = 2A Input Supply Current Standby Mode RUN = 0, VIN Reg Open Maximum BAT Charging Current (Note 3) ADJ Float Reference Voltage (Note 4) 35 V 40 V 1 V 4.6 V 0.3 V 0.55 V 14.7 1.8 3.275 3.25 UNITS V 85 18 l ADJ Recharge Threshold Voltage MAX 3.3 V μA μA 2.1 A 3.325 3.34 V V Threshold Relative to ADJ Float Reference (Note 3) 82.5 ADJ Precondition Threshold Voltage ADJ Rising (Note 4) 2.3 V ADJ Precondition Threshold Hysteresis Voltage Relative to ADJ Precondition Threshold (Note 4) 95 mV ADJ Input Bias Current Charging Terminated CV Operation (Note 5) 65 110 nA nA VINREG Reference Voltage ADJ = 3V, IBAT = 1A l 2.61 2.7 mV 2.83 V VINREG Bias Current VINREG = VINREG Reference 35 100 nA NTC Range Limit (High) Voltage VNTC Rising 1.25 1.36 1.45 V NTC Range Limit (Low) Voltage VNTC Falling 0.27 0.29 0.315 V 250 500 NTC Disable Impedance NTC Bias Current VNTC = 0.8V 45 NTC Threshold Hysteresis For Both High and Low Range Limits RUN Threshold Voltage VRUN Rising 20 1.15 RUN Hysteresis Voltage 1.20 25 TMR Disable Threshold Voltage Operating Frequency Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: The LTM8062E is guaranteed to meet performance specifications from 0°C to 125°C internal. Specifications over the full –40°C to 125°C internal operating temperature range are assured by design, characterization and correlation with statistical process controls. The LTM8062I is guaranteed to meet specifications over the full –40°C to nA 0.4 TMR Charge/Discharge Current 1 V μA 0.25 0.85 V mV –10 10mA Load μA % 1.25 120 RUN Input Bias Current CHRG, FAULT Output Low Voltage kΩ 53 V 1.15 MHz 125°C internal operating temperature range. Note that the maximum internal temperature is determined by specific operating conditions in conjunction with board layout, the rated package thermal resistance and other environmental factors. Note 3: The maximum BAT charging current is reduced by thermal foldback. See the Typical Performance Characteristics for details. Note 4: ADJ voltages measured through 250k equivalent series resistance. Note 5: Output battery float voltage programming resistor divider equivalent resistance = 250k compensates for input bias current. 8062f 3 LTM8062 TYPICAL PERFORMANCE CHARACTERISTICS Efficiency vs IBAT, 4.2V Float Efficiency vs IBAT, 7.2V Float 84 Efficiency vs IBAT, 8.4V Float 87 82 88 VINA = 12V 86 VINA = 12V 87 VINA = 24V 85 VINA = 24V 78 76 86 84 EFFICIENCY (%) EFFICIENCY (%) 80 EFFICIENCY (%) TA = 25°C, unless otherwise noted. VINA = 24V 83 85 VINA = 12V 84 74 82 83 72 81 82 70 80 0 500 1000 IBAT (mA) 1500 2000 81 500 0 1000 IBAT (mA) 1500 8062 G01 2000 0 500 1500 1000 IBAT (mA) 2000 8062 G02 Efficiency vs IBAT, 14.4V Float 8062 G03 ADJ Float Voltage vs Temperature IBIAS vs IBAT, 4.2V Float 25 3.280 90 2500 89 VINA = 24V 20 87 86 85 84 VINA = 12V 3.275 IBIAS (mA) ADJ FLOAT VOLTAGE (V) EFFICIENCY (%) 88 15 10 3.270 VINA = 24V 5 83 82 0 500 1000 IBAT (mA) 1500 2000 3.265 –50 0 –25 25 50 75 0 TEMPERATURE (°C) 0 125 IBIAS vs IBAT, 7.2V Float IBIAS vs IBAT, 8.4V Float 45 40 45 40 35 40 VINA = 12V 30 25 20 5 0 0 0 500 1000 IBAT (mA) 1500 2000 8062 G07 25 20 15 VINA = 24V 10 5 VINA = 24V 30 15 VINA = 24V 10 VINA = 12V IBIAS (mA) IBIAS (mA) 30 2000 35 35 15 1500 IBIAS vs IBAT, 14.4V Float 50 20 1000 IBAT (mA) 8062 G06 45 25 500 8062 G05 8062 G04 IBIAS (mA) 100 10 5 0 500 1000 IBAT (mA) 1500 2000 8062 G08 0 0 500 1000 IBAT (mA) 1500 2000 8062 G09 8062f 4 LTM8062 TYPICAL PERFORMANCE CHARACTERISTICS Input Current vs IBAT, 4.2V Float Input Current vs IBAT, 7.2V Float Input Current vs IBAT, 8.4V Float 1400 900 800 1600 1400 1200 VINA = 12V VINA = 12V 600 INPUT CURRENT (mA) VINA = 12V 500 400 300 VINA = 24V 200 INPUT CURRENT (mA) 700 INPUT CURRENT (mA) TA = 25°C, unless otherwise noted. 1000 800 600 400 VINA = 24V 200 100 0 500 1500 1000 IBAT (mA) 2000 1000 800 600 VINA = 24V 400 200 0 0 1200 0 0 500 1000 IBAT (mA) 1500 8062 G10 2000 0 500 1500 1000 IBAT (mA) 2000 8062 G11 Input Current vs IBAT, 14.4V Float 8062 G12 Maximum IBAT vs ADJ IQ vs VINA, RUN = 0V, VINREG Open 1400 2500 250 2500 200 2000 MAXIMUM IBAT (mA) 1000 150 800 IQ (μA) INPUT CURRENT (mA) 1200 VINA = 24V 600 100 400 1500 1000 500 50 200 0 0 0 0 500 1500 1000 IBAT (mA) 2000 0 10 20 VINA (V) 30 8062 G13 2000 1600 20 TEMPERATURE RISE (°C) 25 CHARGE CURRENT (mA) 2000 1200 800 400 500 0 2 3 2.5 3.5 VINREG (V) 8062 G16 1.5 2 2.5 ADJ VOLTAGE (V) 3 0 –40 –20 3.5 Temperature Rise vs IBAT, 4.2V Float Voltage 2500 1000 1 8062 G15 Maximum Charge Current vs Temperature 1500 0.5 8062 G14 Maximum IBAT vs VINREG MAXIMUM IBAT (mA) 0 40 15 VINA = 24V 10 VINA = 12V 5 0 0 20 40 60 80 100 120 TEMPERATURE (°C) 8062 G17 0 500 1000 IBAT (mA) 1500 2000 8062 G18 8062f 5 LTM8062 TYPICAL PERFORMANCE CHARACTERISTICS Temperature Rise vs IBAT, 8.4V Float Voltage 30 30 25 25 TEMPERATURE RISE (°C) TEMPERATURE RISE (°C) Temperature Rise vs IBAT, 7.2V Float Voltage TA = 25°C, unless otherwise noted. 20 VINA = 24V 15 VINA = 12V 10 VINA = 12V 20 15 VINA = 24V 10 5 5 0 0 0 500 1000 IBAT (mA) 1500 0 2000 500 1000 IBAT (mA) 1500 8062 G20 8062 G19 Temperature Rise vs IBAT, 14.4V Float Voltage VIN Standby Mode Current vs Temperature 40 6 VIN STANDBY MODE CURRENT (mA) 35 TEMPERATURE RISE (°C) 2000 30 25 VINA = 24V 20 15 10 5 0 0 500 1000 IBAT (mA) 1500 2000 8062 G21 5 4 VINA = 12V 3 VINA = 24V 2 1 0 –50 0 50 TEMPERATURE (°C) 100 8062 G22 PIN FUNCTIONS GND (Bank 1, Pin L7): Power and Signal Ground Return. BAT (Bank 2): Battery Charge Current Output Bus. The charge function operates to achieve the final float voltage at this pin. The auto-restart feature initiates a new charging cycle when the voltage at the ADJ pin falls 2.5% below the float voltage. Once the charge cycle is terminated, the input bias current of the BAT pin is reduced to minimize battery discharge while the charger remains connected. VINA (Bank 3): Anode of input reverse protection Schottky diode. Connect the input power here if input reverse voltage protection is desired. VIN (Bank 4): Charger Input Supply. Decouple with at least 4.7μF to GND. Connect the input power here if no input reverse voltage protection is needed. BIAS (Pin G7): The BIAS pin connects to the internal power bus. In most cases connect to VBAT. If this is not desirable, connect to a power source greater than 2.8V and less than 10V. CHRG (Pin K7): Open-Collector Charger Status Output; typically pulled up through a resistor to a reference voltage. This status pin can be pulled up to voltages as high as VIN and can sink currents up to 10mA. During a battery charging cycle, CHRG is pulled low. When the charge current falls below C/10, 8062f 6 LTM8062 PIN FUNCTIONS the CHRG pin becomes high impedance. If the internal timer is used for termination, the pin stays low during the charging cycle until the charge current drops below a C/10 rate, approximately 200mA, even though the charger will continue to top off the battery until the end-of-charge timer terminates the charge cycle. A temperature fault also causes this pin to be pulled low (see the Applications Information section). NTC (Pin H6): Battery Temperature Monitor Pin. This pin is the input to the NTC (negative temperature coefficient) thermistor temperature monitoring circuit. This function is enabled by connecting a 10kΩ, B = 3380 NTC thermistor from the NTC pin to ground. The pin sources 50μA, and monitors the voltage across the 10kΩ thermistor. When the voltage on this pin is above 1.36V (T < 0°C) or below 0.29V (T > 40°C), charging is disabled and the CHRG and FAULT pins are both pulled low. If the internal timer termination is being used, the timer is paused, suspending the charging cycle. Charging resumes when the voltage on NTC returns to within the 0.29V to 1.36V active region. There is approximately 5°C of temperature hysteresis associated with each of the temperature thresholds. The temperature monitoring function remains enabled while thermistor resistance to ground is less than 250kΩ. If this function is not desired, leave the NTC pin unconnected. ADJ (Pin H7): Battery Float Voltage Feedback Input. The charge function operates to achieve a final float voltage of 3.3V on this pin. The output battery float voltage (VBAT(FLT)) is programmed using a resistor divider. VBAT(FLT) can be programmed up to 14.4V. The auto-restart feature initiates a new charging cycle when the voltage at the ADJ pin falls 2.5% below the float voltage reference. The ADJ pin input bias current is 110nA. Using a resistor divider with an equivalent input resistance at the ADJ pin of 250k compensates for input bias current error. Required resistor values to program desired VBAT(FLT) follow the equations: R1= R2 = VBAT(FLT) • 2.5 • 10 5 3.3 R1• 2.5 • 105 R1− (2.5 • 105 ) (Ω) (Ω) R1 is connected from BAT to ADJ, and R2 is connected from ADJ to ground. pin can be pulled up to voltages as high as VIN and can sink currents up to 10mA. This pin indicates charge cycle fault conditions during a battery charging cycle. A temperature fault causes this pin to be pulled low. If the internal timer is used for termination, a bad battery fault also causes this pin to be pulled low. If no fault conditions exist, the FAULT pin remains high impedance (see the Applications Information section). TMR (Pin J6): End-Of-Cycle Timer Programming Pin. If a timerbased charge termination is desired, connect a capacitor from this pin to ground. Full charge end-of cycle time (in hours) is programmed with this capacitor following the equation: tEOC = CTIMER • 4.4 • 106 A bad battery fault is generated if the battery does not reach the precondition threshold voltage within one-eighth of tEOC, or: tPRE = CTIMER • 5.5 • 105 A 0.68μF capacitor is often used, which generates a timer EOC at three hours, and a precondition limit time of 22.5 minutes. If a timer-based termination is not desired, the timer function can be disabled by connecting the TMR pin to ground. With the timer function disabled, charging terminates when the charge current drops below a C/10 rate, approximately 200mA. VINREG (Pin L6): Input Voltage Regulation Reference. The maximum charge current is reduced when this pin is below 2.7V. Connecting a resistor divider from VIN to this sets the minimum operational VIN voltage. This is typically used to program the peak power voltage for a solar panel. The LTM8062 servos the maximum charge current required to maintain the programmed operational VIN voltage, through maintaining the voltage on VINREG at or above 2.7V. If the voltage regulation feature is not used, connect the pin to VIN. RUN (Pin K6): Precision Threshold Enable Input Pin. The RUN threshold is 1.25V (rising), with 120mV of input hysteresis. When in shutdown mode, all charging functions are disabled. The precision threshold allows use of the RUN pin to incorporate UVLO functions. If the RUN pin is pulled below 0.4V, the IC enters a low current shutdown mode where the VIN pin current is reduced to 15μA. Typical RUN pin input bias current is 10nA. If the shutdown function is not desired, connect the pin to the VIN pin. FAULT (Pin J7): Open-Collector Fault Status Output; typically pulled up through a resistor to a reference voltage. This status 8062f 7 LTM8062 BLOCK DIAGRAM VINA VIN 8.2μH 0.1μF 0.1μF SENSE RESISTOR BAT 10μF BIAS VINREG RUN INTERNAL COMPENSATION ADJ CURRENT MODE BATTERY MANAGEMENT CONTROLLER ADJ TMR NTC GND FAULT CHRG 8062 BD OPERATION The LTM8062 is a complete monolithic, mid-power, power tracking battery charger, addressing high input voltage applications with solutions that use a minimum of external components. The product can be programmed for float voltages between 3.3V and 14.4V with just two external resistors, operating under a 1MHz fixed frequency, average current mode step-down architecture. A 2A power Schottky diode is integrated within the μModule for reverse input voltage protection. A wide input range allows the operation to full charge from an input voltage up to 32V. A precision threshold on the RUN pin allows the implementation of a UVLO feature by using a simple resistor network. The charger can also be put into a low current shutdown mode, in which the input supply bias is reduced to only 15μA. The LTM8062 employs an input voltage regulation loop, which reduces charge current if a monitored input voltage falls below a programmed level. When the LTM8062 is powered by a solar panel, the input regulation loop is used to maintain the panel at peak output power. The LTM8062 automatically enters a battery precondition mode if the sensed battery voltage is very low. In this mode, the charge current is reduced to 300mA. Once the battery voltage climbs above the internally set precondition threshold (2.3V at the ADJ pin), the μModule automatically increases the maximum charge current to the full programmed value. The LTM8062 can use a charge current based C/10 termination scheme, which ends a charge cycle when the battery charge current falls to one-tenth the programmed charge current. The LTM8062 also contains an internal charge cycle control timer, for timer-based termination. When using the internal timer, the charge cycle can continue beyond the C/10 level to top-off the battery. The charge cycle terminates when the programmed time elapses, about three hours for a 0.68μF timer capacitor. The CHRG status pin continues to signal charging at a C/10 or greater rate, regardless of 8062f 8 LTM8062 OPERATION which termination scheme is used. When the timer-based scheme is used, the LTM8062 also supports bad battery detection, which triggers a system fault if a battery stays in precondition mode for more than one-eighth of the total programmed charge cycle time. Once charging terminates and the LTM8062 is not actively charging, the charger automatically enters a low current standby mode in which supply bias currents are reduced to 85μA. If the battery voltage drops 2.5% from the full charge float voltage, the LTM8062 engages an automatic charge cycle restart. The IC also automatically restarts a new charge cycle after a bad-battery fault once the failed battery is removed and replaced with another battery. The LTM8062 contains a battery temperature monitoring circuit. This feature, using a thermistor, monitors battery temperature and will not allow charging to begin, or will suspend charging, and signal a fault condition if the battery temperature is outside a safe charging range. The LTM8062 contains two digital open-collector outputs, CHRG and FAULT, which provide charger status and signal fault conditions. These binary coded pins signal battery charging, standby or shutdown modes, battery temperature faults and bad battery faults. For reference, C/10 and TMR based charging cycles are shown in Figures 1 and 2. FLOAT VOLTAGE RECHARGE THRESHOLD BATTERY VOLTAGE PRECONDITION THRESHOLD MAXIMUM CHARGE CURRENT BATTERY CHARGE CURRENT PRECONDITION CURRENT C/10 0 AMPS 1 CHRG 0 1 FAULT 0 1 0 RUN 8062 F01 Figure 1. Typical C/10 Terminated Charge Cycle (TMR Grounded, Time Not to Scale) FLOAT VOLTAGE RECHARGE THRESHOLD BATTERY VOLTAGE PRECONDITION THRESHOLD MAXIMUM CHARGE CURRENT BATTERY CHARGE CURRENT PRECONDITION CURRENT C/10 CURRENT 1 CHRG 0 1 0 1 FAULT RUN 0 < tEOC /8 tEOC AUTOMATIC RESTART 8062 F02 Figure 2. Typical EOC (Timer-Based) Terminated Charge Cycle (Capacitor Connected to TMR, Time Not to Scale) 8062f 9 LTM8062 APPLICATIONS INFORMATION For most applications, the design process is straight forward, summarized as follows: 1. Look at Table 1 and find the row that has the desired input voltage range and battery float voltage. 2. Apply the recommended CIN and RADJ values. Reverse Protection Diode The LTM8062 integrates a high voltage power Schottky diode to provide input reverse voltage protection. The anode of this diode is connected to VINA, and the cathode is connected to VIN. There is a small mount of capacitance at each end; please see the Block Diagram. 3. Connect BIAS as indicated. While these component combinations have been tested for proper operation, it is incumbent upon the user to verify proper operation over the intended system’s line, load and environmental conditions. Bear in mind that the maximum output current is limited by junction temperature, the relationship between the input and output voltage magnitude and polarity and other factors. Please refer to the graphs in the Typical Performance Characteristics section for guidance. Table 1. Recommended Component Values and Configuration (TA = 25°C) VIN RANGE (V)* VBAT (V) CIN RADJ1 TOP (kΩ) 6 to 32 3.6 4.7μF 1206 X7R 50V 274 2870 6 to 32 4.1 4.7μF 1206 X7R 50V 312 1260 RADJ2 BOTTOM (kΩ) 6 to 32 4.2 4.7μF 1206 X7R 50V 320 1150 6.25 to 32 4.7 4.7μF 1206 X7R 50V 357 835 9.5 to 32 7.05 4.7μF 1206 X7R 50V 530 464 9.75 to 32 7.2 4.7μF 1206 X7R 50V 549 459 11 to 32 8.2 4.7μF 1206 X7R 50V 626 417 11.5 to 32 8.4 4.7μF 1206 X7R 50V 642 412 12.75 to 32 9.4 4.7μF 1206 X7R 50V 715 383 16.5 to 32 12.3 4.7μF 1206 X7R 50V 942 344 17 to 32 12.6 4.7μF 1206 X7R 50V 965 340 18.25 to 32 13.5 4.7μF 1206 X7R 50V 1020 328 19 to 32 14.08 4.7μF 1206 X7R 50V 1090 332 19.5 to 32 14.42 4.7μF 1206 X7R 50V 1110 328 Input Supply Voltage Regulation The LTM8062 contains a voltage monitor pin that enables programming a minimum operational voltage. Connecting a resistor divider from VIN to the VINREG pin enables programming of minimum input supply voltage, typically used to program the peak power voltage for a solar panel. Maximum charge current is reduced when the VINREG pin is below the regulation threshold of 2.7V. If the VINREG function is not used, and if the input supply cannot provide enough power to satisfy the requirements of an LTM8062 charger, the input supply voltage will collapse. A minimum operating supply voltage can thus be programmed by monitoring the supply through a resistor divider, such that the desired minimum voltage corresponds to 2.7V at the VINREG pin. The LTM8062 servos the maximum output charge current to maintain the voltage on VINREG at or above 2.7V. Programming of the desired minimum voltage is accomplished by connecting a resistor divider as shown in Figure 3. The ratio of RIN1/RIN2 for a desired minimum voltage (VIN(MIN)) is: RIN1/RIN2 = (VIN(MIN) /2.7) – 1 If the voltage regulation feature is not used, connect the VINREG pin to VIN. INPUT SUPPLY VIN RIN1 * Input bulk capacitance is required. VIN Input Supply The LTM8062 is biased directly from the charger input supply through the VIN pin. This pin provides large switched currents, so a high quality low ESR decoupling capacitor is recommended to minimize voltage glitches on VIN. 4.7μF is typically adequate for most charger applications. LTM8062 VINREG RIN2 8062 F03 Figure 3. Resistive Divider Sets Minimum VIN BIAS Pin Considerations The BIAS pin is used to provide drive power for the internal power switching stage and operate other internal 8062f 10 LTM8062 APPLICATIONS INFORMATION circuitry. For proper operation, it must be powered by at least 2.8V and no more than the absolute maximum rating of 10V. In most applications, connect BIAS to BAT. If there is no BIAS supply available or the battery voltage is below 2.8V, the internal switch requires more headroom from VIN for proper operation. Please refer to the Typical Performance Characteristics curves for minimum start and running requirements under various battery conditions. When charging a 2-cell battery using a relatively high input voltage, the LTM8062 power dissipation can be reduced by connecting BIAS to a voltage between 2.8V and 3.3V. Output Capacitance In many applications, the internal BAT capacitance of the LTM8062 is sufficient for proper operation. There are cases, however, where it may be necessary to add capacitance or otherwise modify the output impedance of the LTM8062. Case 1: the μModule is physically located far from the battery and the added line impedance may interfere with the control loop. Case 2: the battery ESR is very small or very large; the LTM8062 controller is designed for a wide range, but some battery packs have an ESR outside of this range. Case 3: there is no battery at all. As the charger is designed to work with the ESR of the battery, the output may oscillate if no battery is present. The optimum ESR is about 100mΩ, but ESR values both higher and lower will work. Table 2 shows a sample of parts successfully tested by Linear Technology: Table 2 PART NUMBER DESCRIPTION MANUFACTURER 16TQC22M 22μF, 16V, POSCAP Sanyo 35SVPD18M 18μF, 35V, OS-CON Sanyo TPSD226M025R0100 22μF, 25V Tantalum AVX T495D226K025AS 22μF, 25V, Tantalum Kemet TPSC686M006R0150 68μF, 6V, Tantalum AVX TPSB476M006R0250 47μF, 6V, Tantalum AVX APXE100ARA680ME61G 68μF, 10V Aluminum Nippon Chemicon APS-150ELL680MHB5S 68μF, 25V Aluminum Nippon Chemicon If system constraints preclude the use of electrolytic capacitors, a series R-C network may be used. Use a ceramic capacitor of at least 22μF and an equivalent resistance of 100mΩ. An example of this is shown in the Typical Applications section. MPPT Temperature Compensation A typical solar panel is comprised of a number of series-connected cells, each cell being a forward-biased p-n junction. As such, the open-circuit voltage (VOC) of a solar cell has a temperature coefficient that is similar to a common p-n diode, or about –2mV/°C. The peak power point voltage (VMP) for a crystalline solar panel can be approximated as a fixed voltage below VOC, so the temperature coefficient for the peak power point is similar to that of VOC. Panel manufacturers typically specify the 25°C values for VOC, VMP, and the temperature coefficient for VOC, making determination of the temperature coefficient for VMP of a typical panel straight forward. The LTM8062 employs a feedback network to program the VIN input regulation voltage. Manipulation of the network makes for efficient implementation of various temperature compensation schemes for a maximum peak power tracking (MPPT) application. As the temperature characteristic for a typical solar panel VMP voltage is highly linear, a simple solution for tracking that characteristic can be implemented using a Linear Technology LM234 3-terminal temperature sensor. This creates an easily programmable, linear temperature dependent characteristic. In the circuit shown in Figure 4, R IN1 = –RSET • (TC • 4405), and R IN2 = RIN1 VMP (25°C) + RIN1 • (0.0674 / RSET ) VINREG − 1 where TC = temperature coefficient (in V/°C), and VMP(25°C) = maximum power voltage at 25°C. VIN LINEAR TECHNOLOGY LM234 V+ RIN1 V– R RSET VIN VINREG RIN2 LTM8062 8062 F04 Figure 4. MPPT Temperature Compensation Network 8062f 11 LTM8062 APPLICATIONS INFORMATION For example, given a common 36-cell solar panel that has the following specified characteristics: Open Circuit Voltage (VOC) = 21.7V Maximum Power Voltage (VMP) = 17.6V Open-Circuit Voltage Temperature Coefficient (VOC) = –78mV/°C As the temperature coefficient for VMP is similar to that of VOC, the specified temperature coefficient for VOC (TC) of –78mV/°C and the specified peak power voltage (VMP(25°C)) of 17.6V can be inserted into the equations to calculate the appropriate resistor values for the temperature compensation network in Figure 4. With RSET equal to 1k, then: RSET = 1k In a manner similar to the MPPT temperature correction outlined previously, implementation of linear battery charge voltage temperature compensation can be accomplished by incorporating a Linear Technology LM234 into the output feedback network. For example, a 6-cell lead acid battery has a float charge voltage that is commonly specified at 2.25V/cell at 25°C, or 13.5V, and a –3.3mV/°C per cell temperature coefficient, or –19.8mV/°C. Using the feedback network shown in Figure 5, with the desired temperature coefficient (TC) and 25°C float voltage (VFLOAT (25°C)) specified, and using a convenient value of 2.4k for RSET, necessary resistor values follow the relations: RFB1 = –RSET • (TC • 4405) = –2.4k • (–0.0198 • 4405) = 210k RFB2 = R IN1 = −1k • (−0.078 • 4405) = 344k 344k = 24.4k 17.6 + 344k • (0.0674 / 1k) −1 2.7 Battery Voltage Temperature Compensation R IN2 = RFB1 VFLOAT (25°C) + RFB1 • (0.0674 / RSET ) −1 VFB 210k 13.5 + 210k • (0.0674 / 2.4k) −1 3.3 = 43k = Some battery chemistries have charge voltage requirements that vary with temperature. Lead-acid batteries in particular experience a significant change in charge voltage requirements as temperature changes. For example, manufacturers of large lead-acid batteries recommend a float charge of 2.25V/cell at 25°C. This battery float voltage, however, has a temperature coefficient which is typically specified at –3.3mV/°C per cell. RFB3 = 250k – RFB1||RFB2 = 250k – 210k||43k = 215k (see the Battery Float Voltage Programming section) While the circuit in Figure 5 creates a linear temperature characteristic that follows a typical –3.3mV/°C per cell lead-acid specification, the theoretical float charge 14.3 14.2 14.0 BAT LTM8062 RFB3 215k RSET 2.4k R V+ LINEAR TECHNOLOGY V– LM234 + –19.8mV/°C 13.8 6-CELL LEAD-ACID BATTERY ADJ VFLOAT (V) RFB1 210k 13.6 13.4 13.2 RFB2 43k 13.0 8062 F05a 12.8 12.6 –10 0 20 30 10 40 TEMPERATURE (°C) 50 60 8062 F05b Figure 5. Lead-Acid 6-Cell Float Charge Voltage vs Temperature with a –19.8mV/°C Temperature Coefficient Using LM234 with the Feedback Network 8062f 12 LTM8062 APPLICATIONS INFORMATION 14.8 14.6 14.4 14.2 196k LTM8062 198k 69k 6-CELL LEAD-ACID BATTERY + 22k B = 3380 VFLOAT (V) BAT 14.0 THEORETICAL VFLOAT 13.8 13.6 13.4 ADJ 13.2 69k 8062 F06a PROGRAMMED VBAT(FLOAT) 13.0 12.8 –10 0 20 30 10 40 TEMPERATURE (°C) 50 60 8062 F06b Figure 6. Thermistor-Based Temperature Compensation Network Programs VFLOAT to Closely Match Ideal Lead-Acid Float Charge Voltage for 6-Cell Charger voltage characteristic is slightly nonlinear. This nonlinear characteristic follows the relation: VFLOAT = 4 • 10–5 (T2) – 6 • 10–3(T) + 2.375 (with a 2.18V minimum) where T = temperature in °C. A thermistor-based network can be used to approximate the nonlinear ideal temperature characteristic across a reasonable operating range, as shown in Figure 6. Status Pins The LTM8062 reports charger status through two opencollector outputs, the CHRG and FAULT pins. These pins can be pulled up as high as VIN, and can sink up to 10mA. The CHRG pin indicates that the charger is delivering current at greater than a C/10 rate, or one-tenth of the programmed charge current. The FAULT pin signals badbattery and NTC faults. These pins are binary coded, as shown in Table 3. Table 3. Status Pin State CHRG FAULT STATUS High High Not Charging—Standby or Shutdown Mode High Low Bad-Battery Fault (Precondition Timeout/EOC Failure) Low High Normal Charging at C/10 or Greater Low Low NTC Fault (Pause) If the battery is removed from an LTM8062 charger that is configured for C/10 termination, a low amplitude sawtooth waveform appears at the charger output, due to cycling between termination and recharge events. This cycling results in pulsing at the CHRG output. An LED connected to this pin will exhibit a blinking pattern, indicating to the user that a battery is not present. The frequency of this blinking pattern is dependent on the output capacitance. C/10 Charge Termination The LTM8062 supports a low current based termination scheme, where a battery charge cycle terminates when the charge current falls below one-tenth the programmed charge current, or approximately 200mA. This termination mode is engaged by shorting the TMR pin to ground. When C/10 termination is used, an LTM8062 charger sources battery charge current as long as the average current level remains above the C/10 threshold. As the full-charge float voltage is achieved, the charge current falls until the C/10 threshold is reached, at which time the charger terminates and the LTM8062 enters standby mode. The CHRG status pin follows the charger cycle and is high impedance when the charger is not actively charging. There is no provision for bad-battery detection if C/10 termination is used. Timer Charge Termination The LTM8062 supports a timer-based termination scheme, where a battery charge cycle terminates after a specific amount of time elapses. Timer termination is engaged when a capacitor (CTIMER) is connected from the TMR pin to ground. The timer cycle time span (tEOC) is determined by CTIMER in the equation: CTIMER = tEOC • 2.27 • 10–7 (Hours) 8062f 13 LTM8062 APPLICATIONS INFORMATION When charging at a 1C rate, tEOC is commonly set to three hours, which requires a 0.68μF capacitor. The CHRG status pin continues to signal charging, regardless of which termination scheme is used. When timer termination is used, the CHRG status pin is pulled low during a charge cycle until the charge current falls below the C/10 threshold. The charger continues to top off the battery until timer EOC, when the LTM8062 terminates the charge cycle and enters standby mode. Termination at the end of the timer cycle only occurs if the charge cycle was successful. A successful charge cycle occurs when the battery is charged to within 2.5% of the full-charge float voltage. If a charge cycle is not successful at EOC, the timer cycle resets and charging continues for another full timer cycle. When VBAT drops 2.5% from the full-charge float voltage, whether by battery loading or replacement of the battery, the charger automatically resets and starts charging. Preconditioning and Bad-Battery Fault The LTM8062 has a precondition mode, where the charge current is limited to 15% of the maximum charge current, or approximately 300mA. Precondition mode is engaged if the voltage on the BAT pin is below the precondition threshold, or approximately 70% of the float voltage. Once the BAT voltage rises above the precondition threshold, normal fullcurrent charging can commence. The LTM8062 incorporates 90mV hysteresis to avoid spurious mode transitions. Bad-battery detection is engaged when the internal timer is used for termination (capacitor tied to TMR). This fault detection feature is designed to identify failed cells. A bad-battery fault is triggered when the voltage on BAT remains below the precondition threshold for greater than one-eighth of a full timer cycle (one-eighth EOC). A badbattery fault is also triggered if a normally charging battery re-enters precondition mode after one-eighth EOC. When a bad-battery fault is triggered, the charge cycle is suspended, and the CHRG status pin becomes high impedance. The FAULT pin is pulled low to signal that a fault has been detected. Cycling the charger’s power or shutdown function initiates a new charge cycle, but the LTM8062 charger does not require a manual reset. Once a bad-battery fault is detected, a new timer charge cycle initiates if the BAT pin exceeds the precondition threshold voltage. During a bad-battery fault, a small current is sourced from the charger; removing the failed battery allows the charger output voltage to rise above the preconditioning threshold voltage and initiate a charge cycle reset. A new charge cycle is started by connecting another battery to the charger output. Battery Temperature Fault: NTC The LTM8062 can accommodate battery temperature monitoring by using an NTC (negative temperature coefficient) thermistor close to the battery pack. The temperature monitoring function is enabled by connecting a 10kΩ, β ≈ 3380 NTC thermistor from the NTC pin to ground. If the NTC function is not desired, leave the pin open. The NTC pin sources 50μA, and monitors the voltage dropped across the 10kΩ thermistor. When the voltage on this pin is above 1.36V (0°C) or below 0.29V (40°C), the battery temperature is out of range, and the LTM8062 triggers an NTC fault. The NTC fault condition remains until the voltage on the NTC pin corresponds to a temperature within the 0°C to 40°C range. Both hot and cold thresholds incorporate 20% hysteresis, which equates to about 5°C. If higher operational charging temperatures are desired, the temperature range can be expanded by adding series resistance to the 10k NTC resistor. Adding a 909Ω resistor will increase the effective temperature threshold to 45°C, for example. During an NTC fault, charging is halted and both status pins are pulled low. If timer termination is enabled, the timer count is suspended and held until the fault condition is cleared. Thermal Foldback The LTM8062 contains a thermal foldback protection feature that reduces charge current as the IC junction temperature approaches 125°C. In most cases, on-chip temperatures servo such that any overtemperature conditions are relieved with only slight reductions in maximum charge current. In some cases, the thermal foldback protection feature can reduce charge currents below the C/10 threshold. In applications that use C/10 termination (TMR = 0V), the LTM8062 will suspend charging and enter standby mode until the overtemperature condition is relieved. 8062f 14 LTM8062 APPLICATIONS INFORMATION ADJ BAT NTC FAULT TMR CHRG GND (OPTIONAL) RUN VINREG CBAT VINA GND CIN VIN 8062 F07 THERMAL VIAS Figure 7. Suggested Layout and Via Placement PCB Layout Most of the headaches associated with PCB layout have been alleviated or even eliminated by the high level of LTM8062 integration. The LTM8062 is nevertheless a switching power supply, and care must be taken to minimize EMI and ensure proper operation. Even with the high level of integration, you may fail to achieve specified operation with a haphazard or poor layout. See Figure 7 for a suggested layout. Ensure that the grounding and heat sinking are acceptable. 1. Place the CIN capacitor as close as possible to the VIN and GND connection of the LTM8062. 2. If used, place the CBAT capacitor as close as possible to the BAT and GND connection of the LTM8062. 3. Place the CIN and CBAT (if used) capacitors such that their ground current flows directly adjacent or underneath the LTM8062. 4. Connect all of the GND connections to as large a copper pour or plane area as possible on the top layer. Avoid breaking the ground connection between the external components and the LTM8062. 5. For good heat sinking, use vias to connect the GND copper area to the board’s internal ground planes. Liberally distribute these GND vias to provide both a good ground connection and thermal path to the internal planes of the printed circuit board. Pay attention to the location and density of the thermal vias in Figure 5. The LTM8062 can benefit from the heat-sinking afforded by vias that connect to internal GND planes at these locations, due to their proximity to internal power handling components. The optimum number of thermal vias depends upon the printed circuit board design. For example, a board might use very small via holes. It should employ more thermal vias than a board that uses larger holes. Hot-Plugging Safely The small size, robustness and low impedance of ceramic capacitors make them an attractive option for the input bypass capacitor of LTM8062. However, these capacitors can cause problems if the LTM8062 is plugged into a live input supply (see Application Note 88 for a complete discussion). The low loss ceramic capacitor combined with stray inductance in series with the power source forms an underdamped tank circuit, and the voltage at the VIN pin of the LTM8062 can ring to more than twice the nominal input voltage, possibly exceeding the LTM8062’s rating and damage the part. If the input supply is poorly controlled or the user will be plugging the LTM8062 into an energized supply, the input network should be designed to prevent this overshoot. This can be accomplished by installing a small resistor in series with VIN, but the most popular method of controlling input voltage overshoot is 8062f 15 LTM8062 APPLICATIONS INFORMATION to add an electrolytic bulk capacitor to the VIN net. This capacitor’s relatively high equivalent series resistance damps the circuit and eliminates the voltage overshoot. The extra capacitor improves low frequency ripple filtering and can slightly improve the efficiency of the circuit, though it is physically large. Thermal Considerations The thermal performance of the LTM8062 is given in the Typical Performance Characteristics section. These curves were generated by the LTM8062 mounted to a 58cm2 4-layer FR4 printed circuit board. Boards of other sizes and layer count can exhibit different thermal behavior, so it is incumbent upon the user to verify proper operation over the intended system’s line, load and environmental operating conditions. For increased accuracy and fidelity to the actual application, many designers use FEA to predict thermal performance. To that end, the Pin Configuration section of the data sheet typically gives four thermal coefficients: 1. θJA: Thermal resistance from junction to ambient. 2. θJCbottom : Thermal resistance from junction to the bottom of the product case. 3. θJCtop : Thermal resistance from junction to top of the product case. 4. θJB: Thermal resistance from junction to the printed circuit board. While the meaning of each of these coefficients may seem to be intuitive, JEDEC has defined each to avoid confusion and inconsistency. These definitions are given in JESD 51-12, and are quoted or paraphrased below: 1. θJA is the natural convection junction-to-ambient air thermal resistance measured in a one cubic foot sealed enclosure. This environment is sometimes referred to as “still air” although natural convection causes the air to move. This value is determined with the part mounted to a JESD 51-9 defined test board, which does not reflect an actual application or viable operating condition. 2. θJCbottom is the junction-to-board thermal resistance with all of the component power dissipation flowing through the bottom of the package. In the typical μModule, the bulk of the heat flows out the bottom of the package, but there is always heat flow out into the ambient environment. As a result, this thermal resistance value may be useful for comparing packages but the test conditions don’t generally match the user’s application. 3. θJCtop is determined with nearly all of the component power dissipation flowing through the top of the package. As the electrical connections of the typical μModule are on the bottom of the package, it is rare for an application to operate such that most of the heat flows from the junction to the top of the part. As in the case of θJCbottom, this value may be useful for comparing packages but the test conditions don’t generally match the user’s application. 4. θJB is the junction-to-board thermal resistance where almost all of the heat flows through the bottom of the μModule and into the board, and is really the sum of the θJCbottom and the thermal resistance of the bottom of the part through the solder joints and through a portion of the board. The board temperature is measured a specified distance from the package, using a two sided, two layer board. This board is described in JESD 51-9. The most appropriate way to use the coefficients is when running a detailed thermal analysis, such as FEA, which considers all of the thermal resistances simultaneously. None of them can be individually used to accurately predict the thermal performance of the product, so it would be inappropriate to attempt to use any one coefficient to correlate to the junction temperature versus load graphs given in the LTM8033 data sheet. A graphical representation of these thermal resistances is given in Figure 8. The blue resistances are contained within the μModule, and the green are outside. The die temperature of the LTM8062 must be lower than the maximum rating of 125°C, so care should be taken in the layout of the circuit to ensure good heat sinking of the LTM8062. The bulk of the heat flow out of the LTM8062 is through the bottom of the module and the LGA pads into the printed circuit board. Consequently a poor printed circuit board design can cause excessive heating, resulting in impaired performance or reliability. Please refer to the PCB Layout section for printed circuit board design suggestions. 8062f 16 LTM8062 APPLICATIONS INFORMATION JUNCTION-TO-AMBIENT RESISTANCE (JESD 51-9 DEFINED BOARD) CASE (TOP)-TO-AMBIENT RESISTANCE JUNCTION-TO-CASE (TOP) RESISTANCE JUNCTION-TO-BOARD RESISTANCE JUNCTION AMBIENT JUNCTION-TO-CASE CASE (BOTTOM)-TO-BOARD (BOTTOM) RESISTANCE RESISTANCE BOARD-TO-AMBIENT RESISTANCE 80421 F08 μMODULE DEVICE Figure 8. Thermal Resistances Among μModule Device Printed Circuit Board and Ambient Environment TYPICAL APPLICATIONS Basic 2A, 2-Cell LiFePO4 Battery Charger with C/10 Termination VIN 9.5V TO 32VDC VINA LTM8062 VIN 4.7μF BAT + BIAS VINREG CHRG RUN FAULT TMR ADJ NTC 2-CELL LiFePO4 (2× 3.6V) BATTERY 549k (OPTIONAL ELECTROLYTIC CAPACITOR) 459k GND 8062 TA02 2A Solar Panel Power Manager with 8.4V Lithium Ion Battery Pack and 16V Peak Power Tracking VIN SOLAR POWER UNIT VINA LTM8062 VIN 499k 4.7μF 100k BAT BIAS VINREG CHRG RUN FAULT TMR ADJ NTC 642k + (OPTIONAL ELECTROLYTIC CAPACITOR) 2-CELL Li-ION (2× 4.2V) BATTERY NTC 10k B = 3380 412k GND 8062 TA03 8062f 17 0.9525 1.5875 4 2.540 15 BSC Y aaa Z 3.95 – 4.05 DETAIL A 0.635 ±0.025 SQ. 76x 0.27 – 0.37 SUBSTRATE eee S X Y DETAIL B MOLD CAP DETAIL B 4.22 – 4.42 6.350 5.080 3.810 2.540 1.270 DETAILS OF PAD #1 IDENTIFIER ARE OPTIONAL, BUT MUST BE LOCATED WITHIN THE ZONE INDICATED. THE PAD #1 IDENTIFIER MAY BE EITHER A MOLD OR MARKED FEATURE 4 SYMBOL TOLERANCE aaa 0.15 bbb 0.10 eee 0.05 6. THE TOTAL NUMBER OF PADS: 77 5. PRIMARY DATUM -Z- IS SEATING PLANE LAND DESIGNATION PER JESD MO-222, SPP-010 3 2. ALL DIMENSIONS ARE IN MILLIMETERS X 0.000 SUGGESTED PCB LAYOUT TOP VIEW 2.540 NOTES: 1. DIMENSIONING AND TOLERANCING PER ASME Y14.5M-1994 3.810 1.270 2.540 3.810 5.080 6.350 PACKAGE TOP VIEW 1.270 PAD 1 CORNER 9 BSC 0.000 aaa Z 4.1275 3.4925 3.810 0.9525 1.5875 1.270 (Reference LTC DWG # 05-08-1856 Rev A) Z 18 // bbb Z LGA Package 77-Lead (15mm × 9mm × 4.32mm) TRAY PIN 1 BEVEL COMPONENT PIN “A1” 3 PADS SEE NOTES 1.27 BSC 12.70 BSC 7 5 7.62 BSC 4 3 2 1 L K J H G F E D C B A PAD 1 DIA (0.635) LGA 77 0909 REV A PACKAGE IN TRAY LOADING ORIENTATION LTMXXXXXX MModule PACKAGE BOTTOM VIEW 6 DETAIL A LTM8062 PACKAGE DESCRIPTION 8062f LTM8062 PACKAGE DESCRIPTION Table 3. Pin Assignment Table (Arranged by Pin Number) PIN NAME PIN NAME PIN NAME PIN NAME PIN NAME PIN NAME A1 GND B1 GND C1 GND D1 GND E1 GND F1 GND A2 GND B2 GND C2 GND D2 GND E2 GND F2 GND A3 GND B3 GND C3 GND D3 GND E3 GND F3 GND A4 GND B4 GND C4 GND D4 GND E4 GND F4 GND A5 GND B5 GND C5 GND D5 GND E5 GND F5 GND A6 BAT B6 BAT C6 BAT D6 BAT E6 BAT F6 BAT A7 BAT B7 BAT C7 BAT D7 BAT E7 BAT F7 BAT PIN NAME PIN NAME PIN NAME PIN NAME PIN NAME G1 GND H1 GND J1 GND K1 VIN L1 VIN G2 GND H2 GND J2 GND K2 VIN L2 VIN G3 GND H3 GND J3 GND K3 VIN L3 VIN G4 GND H4 GND J4 GND K4 VINA L4 VINA G5 GND H5 GND J5 GND K5 VINA L5 VINA G6 GND H6 NTC J6 TMR K6 RUN L6 VINREG G7 BIAS H7 ADJ J7 FAULT K7 CHRG L7 GND PACKAGE PHOTO 8062f Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 19 LTM8062 TYPICAL APPLICATION 2A Solar Panel Power Manager for Charging 2-Cell 8.4V Lithium-Ion Battery, Featuring Three Hour Charge Time and 16V Peak Power Tracking. Battery Powers Two μModule Regulators VIN SOLAR POWER UNIT VINA LTM8062 VIN 499k 4.7μF 0.68μF 100k BAT LTM8023 VOUT LTM8021 VOUT BIAS VINREG CHRG RUN FAULT TMR ADJ NTC 642k 2-CELL Li-Ion (2s 4.2V) BATTERY NTC 10k B = 3380 412k GND 8062 TA04 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LTM4600 10A DC/DC μModule Regulator Basic 10A DC/DC μModule, 15mm × 15mm × 2.8mm LGA LTM4600HVMPV Military Plastic 10A DC/DC μModule Regulator –55°C to 125°C Operation, 15mm × 15mm × 2.8mm LGA LTM4601/ LTM4601A 12A DC/DC μModule Regulator with PLL, Output Tracking/Margining and Remote Sensing Synchronizable, PolyPhase Operation, LTM4601-1 Version has no Remote Sensing LTM4602 6A DC/DC μModule Regulator Pin Compatible with the LTM4600 LTM4603 6A DC/DC μModule Regulator with PLL and Output Synchronizable, PolyPhase Operation, LTM4603-1 Version has no Remote Tracking/Margining and Remote Sensing Sensing, Pin Compatible with the LTM4601 LTM4604A 4A Low VIN DC/DC μModule Regulator 2.375V ≤ VIN ≤ 5V, 0.8V ≤ VOUT ≤ 5V, 9mm × 15mm × 2.3mm LGA LTM4608A 8A Low VIN DC/DC μModule Regulator 2.375V ≤ VIN ≤ 5V, 0.8V ≤ VOUT ≤ 5V, 9mm × 15mm × 2.8mm LGA LTM8020 200mA, 36V DC/DC μModule Regulator EN55022 Class B Compliant, Fixed 450kHz Frequency, 1.25V ≤ VOUT ≤ 5V, 6.25mm × 6.25mm × 2.32mm LGA LTM8022 1A, 36V DC/DC μModule Regulator Adjustable Frequency, 0.8V ≤ VOUT ≤ 5V, 9mm × 11.25mm × 2.82mm LGA, Pin Compatible to the LTM8023 LTM8023 2A, 36V DC/DC μModule Regulator Adjustable Frequency, 0.8V ≤ VOUT ≤ 5V, 9mm × 11.25mm × 2.82mm LGA, Pin Compatible to the LTM8022 LTM8025 3A, 36V DC/DC μModule Regulator 0.8V ≤ VOUT ≤ 24V, 9mm × 15mm × 4.32mm LGA LTM8021 500mA, 36V DC/DC μModule Regulator EN55022 Class B Compliant, Fixed 1.1MHz Frequency, 0.8V ≤ VOUT ≤ 5V, 6.25mm × 11.25mm × 2.82mm LGA 8062f 20 Linear Technology Corporation LT 0810 • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2010