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LT3650EMSE-8.4#PBF

LT3650EMSE-8.4#PBF

  • 厂商:

    LINEAR(凌力尔特)

  • 封装:

    MSOP12_4X3MM_EP

  • 描述:

    Charger IC Lithium-Ion/Polymer 12-MSOP-EP

  • 数据手册
  • 价格&库存
LT3650EMSE-8.4#PBF 数据手册
LT3650-8.2/LT3650-8.4 High Voltage 2 Amp Monolithic 2-Cell Li-Ion Battery Charger Description Features Wide Input Voltage Range: 9V to 32V (40V Absolute Maximum) n Programmable Charge Current: Up to 2A n User-Selectable Termination: C/10 or Onboard Termination Timer n Dynamic Charge Rate Programming/Soft-Start Pin n Programmable Input Current Limit n 1MHz Fixed Frequency n Average Current Mode Control n 0.5% Float Voltage Accuracy n 5% Charge Current Accuracy n 2.5% C/10 Detection Accuracy n NTC Resistor Temperature Monitor n Auto-Recharge at 97.5% Float Voltage n Auto-Precondition at 2V. Typical Performance Characteristics 50 25 0 75 TEMPERATURE (°C) UNITS 22.5 Timer Accuracy –25 MAX 0.4 l Precondition Timeout –50 TYP 65 –50 –25 50 0 25 TEMPERATURE (°C) 75 100 365082 G02 0 0 0.2 0.4 0.8 0.6 VRNG/SS 1.0 1.2 365082 G03 36508284fd 4 LT3650-8.2/LT3650-8.4 Typical Performance Characteristics Switch Drive (ISW/IBOOST) vs Switch Current Switch Forward Drop (VIN – VSW) vs Temperature 36 480 33 SWITCH FORWARD DROP (mV) 27 21 18 15 12 9 6 440 0 400 380 VCLP – VIN (mV) 10 9 –25 50 25 0 75 TEMPERATURE (°C) 100 125 50 25 0 75 TEMPERATURE (°C) –25 100 –350 125 100.8 50.6 100.6 50.4 100.4 50.2 50.0 49.8 49.6 100 60 40 20 25 35 45 55 65 75 85 95 105 115 125 135 TEMPERATURE (°C) 365082 G10 6 8 8.5 365082 G06 100 VBAT = 7.5V 99.6 99.2 99.0 –50 125 50 25 0 75 TEMPERATURE (°C) –25 365082 G08 125 100 365082 G09 Battery Bias Current with Charger Disabled (IBAT + ISENSE + IBOOST + ISW) CC/CV Charging; BAT Pin Bias Current vs VBAT 10 LT3650-8.2 9 8 IBAT (mA) 80 2 2.5 5.5 VSENSE (V) 99.8 99.4 2.2 2.0 1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0 –0.2 –0.4 1.5 100.0 49.2 50 25 0 75 TEMPERATURE (°C) 1 100.2 49.4 –25 0.5 IMAX Current Limit (VSENSE – VBAT) vs Temperature 50.8 49.0 –50 0 365082 G05 101.0 365082 G07 120 VSENSE – VBAT (mV) –300 51.0 Thermal Foldback – IMAX Current Limit (VSENSE – VBAT) vs Temperature 0 –150 CLP Input Limit Threshold (VCLP – VIN) vs Temperature ICHG at 50% C/10 Threshold vs Temperature (VSENSE – VBAT) 8 –50 –100 –250 320 –50 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 SWITCH CURRENT (A) 365082 G04 LT3650-8.2 –200 360 VSENSE – VBAT (mV) 0 CC/CV Charging; SENSE Pin Bias Current vs VSENSE –50 340 11 VSENSE – VBAT (mV) 50 420 3 12 460 BATTERY CURRENT (µA) ISW/IBOOST 24 100 ISW = 2A ISENSE (µA) 30 0 TA = 25°C, unless otherwise noted. 7 6 VIN FLOATING 5 4 3 2 1 0 0.5 1 1.5 2 2.5 VBAT (V) 3 3.5 8 8.5 365082 G11 0 VIN = 20V, VSHDN = 0V 0 1 2 3 4 5 VBAT (V) 6 7 8 9 365082 G12 36508284fd 5 LT3650-8.2/LT3650-8.4 Pin Functions VIN (Pin 1): Charger Input Supply. VIN pin operating range is 9V to 32V. VIN ≥ 11.5V or (VBOOST – VSW) > 2V is required for start-up. IVIN = 85µA after charge termination. be pulled low. If no fault conditions exist, the FAULT pin remains high impedance (see the Applications Information section). CLP (Pin 2): System Current Limit Input. System current levels can be monitored by connecting the input power supply to the CLP pin and connecting a sense resistor from the CLP pin to the VIN pin. Additional system load is drawn from the VIN pin connection, and maximum system load is achieved when VCLP – VVIN = 50mV. The LT3650 servos the maximum charge current required to maintain programmed maximum system current. If this function is not desired, connect the CLP pin to the VIN pin (see the Applications Information section). TIMER (Pin 6): End-Of-Cycle Timer Programming Pin. If a timer-based charge termination is desired, connect a capacitor from this pin to ground. Full charge end-ofcycle time (in hours) is programmed with this capacitor following the equation: SHDN (Pin 3): Precision Threshold Shutdown Pin. The enable threshold is 1.225V (rising), with 120mV of input hysteresis. When in shutdown mode, all charging functions are disabled. The precision threshold allows use of the SHDN pin to incorporate UVLO functions. If the SHDN pin is pulled below 0.4V, the IC enters a low current shutdown mode where the VIN pin current is reduced to 15µA. Typical SHDN pin input bias current is 10nA. If the shutdown function is not desired, connect the pin to the VIN pin. CHRG (Pin 4): 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 when disabled, and can sink currents up to 10mA when enabled. During a battery charging cycle, CHRG is pulled low. When the charge cycle is terminated, 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, or ICHG(MAX)/10. A temperature fault also causes this pin to be pulled low (see the Applications Information section). FAULT (Pin 5): Open-Collector Fault 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 when disabled, and can sink currents up to 10mA when enabled. 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 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 typically 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 is disabled by connecting the TIMER pin to ground. With the timer function disabled, charging terminates when the charge current drops below a C/10 rate, or ICHG(MAX)/10. RNG/SS (Pin 7): Charge Current Programming Pin. This pin allows a dynamic adjustment of the maximum charge current, and can be used to employ a soft-start function. Maximum charge current is adjusted by setting the voltage on this pin, such that the maximum desired voltage across the inductor current sense resistor (VSENSE – VBAT) is 0.1 • VRNG/SS, so the maximum charge current reduces to: VRNG/SS • ICHG(MAX) This pin has an effective range from 0V to 1V. 50µA is sourced from this pin, so the maximum charge current can be programmed by connecting a resistor (RRNG/SS) from RNG/SS to ground, such that the voltage dropped across the resistor is equivalent to the desired programming voltage, or: VRNG/SS = 50µA • RRNG/SS Soft-start functionality can be implemented by connecting a capacitor (CRNG/SS) from RNG/SS to ground, such that the time required to charge the capacitor to 1V (full 36508284fd 6 LT3650-8.2/LT3650-8.4 Pin Functions charge current) is the desired soft-start interval (tSS). For no RRNG/SS, this capacitor value follows the relation: CRNG/SS = 50µA • tSS The RNG/SS pin is pulled low during fault conditions, allowing graceful recovery from faults should soft-start functionality be implemented. Both the soft-start capacitor and the programming resistor can be implemented in parallel. All C/10 monitoring functions are disabled while VRNG/SS is below 0.1V to accommodate long soft-start intervals. RNG/SS voltage can also be manipulated using an active device, employing a pull-down transistor to disable charge current or to dynamically servo maximum charge current. Manipulation of the RNG/SS pin with active devices that have low impedance pull-up capability is not allowed (see the Applications Information section). NTC (Pin 8): 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 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, so if this function is not desired, leave the NTC pin unconnected. BAT (Pin 9): Battery Voltage Monitor Pin. Connect 10µF decoupling capacitance (CBAT) from this pin to ground. Depending on application requirements, larger value decoupling capacitors may be required (see the Application Information section). 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 BAT pin falls 2.5% below this float voltage. Once the charge cycle is terminated, the input bias current of the BAT pin is reduced to 2V. 1 2  V   V  ICVIN(RMS)  ICHG(MAX) •  BAT  •   IN  − 1  VIN    VBAT    which has a maximum at VIN = 2 • VBAT, where: ICVIN(RMS) = ICHG(MAX)/2 The simple worst-case of 1/2 • ICHG(MAX) is commonly used for design. Bulk capacitance is a function of desired input ripple voltage (∆VIN), and follows the relation: V /V  CIN(BULK) = IMAX •  BAT IN  (µF )  ∆VIN  10µF is typically adequate for most charger applications. BOOST Supply The BOOST bootstrapped supply rail drives the internal switch and facilitates saturation of switch transistor. Operating range of the BOOST pin is 0V to 8.5V, as referenced to the SW pin. Connect a 1µF or greater capacitor from the BOOST pin to the SW pin. The voltage on the decoupling capacitor is refreshed through a diode, with the anode connected to/from either the battery output voltage or an external source, and the cathode connected to the BOOST pin. Rate the diode average current greater than 0.1A, and its reverse voltages greater than VIN(MAX). When an LT3650 charger is not switching, the SW pin is at the same potential as the battery, which can be as high as VBAT(FLT). For reliable start-up, the VIN supply must be at least 3V above the SW pin. The minimum start-up specification of VIN at or above 11.5V provides ample margin to satisfy this requirement. Once switching begins, the BOOST supply capacitor gets charged such that (VBOOST – VSW) > 2V, and the VIN requirement no longer applies. In low VIN applications, the BOOST supply can be powered by an external source for start-up, eliminating the VIN start-up requirement. VBAT Output Decoupling An LT3650 charger output requires bypass capacitance connected from the BAT pin to ground (CBAT). A 10µF ceramic capacitor is required for all applications. In systems where the battery can be disconnected from the charger output, additional bypass capacitance may be desired for visual indication of a no-battery condition (see the Status Pins section). If it is desired to operate a system load from the LT3650 charger output when the battery is disconnected, additional bypass capacitance is required. In this type of application with the charger being used as a DC/DC converter, excessive ripple and/or low amplitude oscillations can occur without additional output bulk capacitance. For these applications, place a 100µF low ESR nonceramic capacitor (chip tantalum or organic semiconductor capacitors such as Sanyo OS-CONs or POSCAPs) from BAT to ground, in parallel with the 10µF ceramic bypass capacitor. This additional bypass capacitance may also be required in systems where the battery is connected to the charger through long wires. The voltage rating on CBAT must meet or exceed the battery float voltage. 36508284fd 11 LT3650-8.2/LT3650-8.4 Applications Information RSENSE : Charge Current Programming The LT3650 charger is configurable to charge at average currents as high as 2A. Maximum charge current is set by choosing an inductor sense resistor such that the desired maximum average current through that sense resistor creates a 100mV drop, or: 0.1 RSENSE = IMAX(AVG) where IMAX(AVG) is the maximum average charge current. A 2A charger, for example, would use a 0.05Ω sense resistor. to 35% of IMAX, so an inductor value can be determined by setting 0.25 < ∆IMAX < 0.35. Magnetics vendors typically specify inductors with maximum RMS and saturation current ratings. Select an inductor that has a saturation current rating at or above (1+∆IMAX/2) • IMAX, and an RMS rating above IMAX. Inductors must also meet a maximum volt-second product requirement. If this specification is not in the data sheet of an inductor, consult the vendor to make sure the maximum volt-second product is not being exceeded by your design. The minimum required volt-second product is:  VBAT  VBAT •  1 −  (V • µs) VIN(MAX)   SW BOOST LT3650 SENSE RSENSE BAT 365082 F01 Figure 1. Programming Maximum Charge Current Using RSENSE SWITCHED INDUCTOR VALUE (µH) 14 Inductor Selection  10  L=  • RSENSE • (VBAT + VF )  ∆IMAX    V + V  •  1−  BAT F  (µH) +V  V   IN(MAX) F  In the previous relation, ∆IMAX is the normalized ripple current, VIN(MAX) as the maximum operational voltage, and VF is the forward voltage of the rectifying Schottky diode. Ripple current is typically set within a range of 25% 12 10 8 6 4 2 0 9 12 15 18 21 24 27 30 32 MAXIMUM OPERATIONAL VIN VOLTAGE (V) 365082 F02 Figure 2. 2A Charger Switched Inductor Value (RSENSE = 0.05Ω) 25% to 35% IMAX Ripple Current 20 SWITCHED INDUCTOR VALUE (µH) The primary criteria for inductor value selection in an LT3650 charger is the ripple current created in that inductor. Once the inductance value is determined, an inductor must also have a saturation current equal to or exceeding the maximum peak current in the inductor. An inductor value (L), given the desired amount of ripple current (∆IMAX) can be approximated using the relation: 12 18 16 14 12 10 8 6 4 2 0 9 12 15 18 21 24 27 30 32 MAXIMUM OPERATIONAL VIN VOLTAGE (V) 365082 F03 Figure 3. 1.3A Charger Switched Inductor Value (RSENSE = 0.075Ω) 25% to 35% IMAX Ripple Current 36508284fd LT3650-8.2/LT3650-8.4 Applications Information Rectifier Selection CLP: System Current Limit The rectifier diode in an LT3650 battery charger provides a current path for the inductor current when the main power switch is disabled. The rectifier is selected based upon forward voltage, reverse voltage, and maximum current. A Schottky diode is required, as low forward voltage yields the lowest power loss and highest efficiency. The rectifier diode must be rated to withstand reverse voltages greater than the maximum VIN voltage. The LT3650 contains a PowerPathTM control feature to support multiple load systems. The charger adjusts output current in response to a system load if overall input supply current exceeds the programmed maximum value. The minimum average diode current rating (IDIODE(MAX)) is calculated with maximum output current (IMAX), maximum operational VIN, and output at the precondition threshold (VBAT(PRE)): IMAX • (VIN(MAX) − VBAT(PRE) ) IDIODE(MAX) > (A) VIN(MAX) For example, a rectifier diode for an 8.2V, 1.5A charger with a 20V maximum input voltage would require: Maximum input supply current is set by choosing a sense resistor (RCLP) such that the desired maximum current through that sense resistor creates a 50mV drop, or: 0.05 RCLP = IMAX(IN) where IMAX(IN) is the maximum input current. A 1.5A system limit, for example, would use a 33mΩ sense resistor. The LT3650 integrates the CLP signal internally, so average current limiting is performed in most cases without the need for external filter elements. 1.5 • (20 − 5.65) ,or 20 IDIODE(MAX) > 1.1A IDIODE(MAX) > SYSTEM LOAD CURRENT 1.5A SYSTEM LOAD INPUT SUPPLY RCLP 1.0A VIN LT3650 INPUT CURRENT (IVIN) LT3650 0.5A CLP 365082 F04 Figure 4. RCLP Sets the Input Supply Current Limit 365082 F05 Figure 5. CLP Limit: Charger Current vs System Load Current with 1.5A Limit 36508284fd 13 LT3650-8.2/LT3650-8.4 Applications Information RNG/SS: Dynamic Charge Current Adjust The LT3650 gives the user the capability to adjust maximum charge current dynamically through the RNG/SS pin. The voltage on the RNG/SS pin corresponds to ten times the maximum voltage across the sense resistor (RSENSE). The default maximum sense voltage is 100mV, so maximum charge current can be expressed as: This feature could be used, for example, to switch in a reduced charge current level. Active servos can also be used to impose voltages on the RNG/SS pin, provided they can only sink current. Active circuits that source current cannot be used to drive the RNG/SS pin. Resistive pullups can be used, but extreme care must be taken not to exceed the 2.5V absolute maximum voltage on the pin. IMAX(RNG/SS) = IMAX • VRNG/SS RNG/SS: Soft-Start where IMAX(RNG/SS) is the maximum charge current if VRNG/SS is within 0V to 1V. Voltages higher than 1V have no effect on the maximum charge current. Soft-start functionality is also supported by the RNG/SS pin. 50µA is sourced from the RNG/SS pin, so connecting a capacitor from the RNG/SS pin to ground (CRNG/SS) creates a linear voltage ramp. The maximum charge current follows this voltage. Thus, the charge current increases from zero to the fully programmed value as the capacitor charges from 0V to 1V. The value of CRNG/SS is calculated based on the desired time to full current (tSS) following the relation: The LT3650 sources 50µA from the RNG/SS pin, such that a current control voltage can be set by simply connecting an appropriately valued resistor to ground, following the relation: V RRNG/SS = RNG/SS 50µA For example, to reduce the maximum charge current to 50% of the original value, which corresponds to a maximum sense voltage of 50mV, RNG/SS would be set to 0.5V. 0.5V RRNG/SS = = 10kΩ 50µA CRNG/SS = 50µA • tSS The RNG/SS pin is pulled to ground internally when charging is terminated so each new charging cycle begins with a soft-start cycle. RNG/SS is also pulled to ground during bad-battery and NTC fault conditions, so a graceful recovery from these faults is possible. LT3650 LT3650 RNG/SS RNG/SS 10k 365082 F06 365082 F07 LOGIC HIGH = HALF CURRENT Figure 6. Using the RNG/SS Pin for Digital Control of Maximum Charge Current + – SERVO REFERENCE Figure 7. Driving the RNG/SS Pin with a Current-Sink Active Servo Amplifier LT3650 RNG/SS CPROG 365082 F08 Figure 8. Using the RNG/SS Pin for Soft-Start 36508284fd 14 LT3650-8.2/LT3650-8.4 Applications Information Status Pins The LT3650 reports charger status through two opencollector outputs, the CHRG and FAULT pins. These pins can accept voltages as high as VIN, and can sink up to 10mA when enabled. The CHRG pin indicates that the charger is delivering current at greater than a C/10 rate, or one-tenth of the programmed maximum charge current. The FAULT pin signals bad-battery and NTC faults. These pins are binary coded, and signal following the table below, where On indicates the pin pulled low, and Off indicates pin high impedance: voltage is achieved, the charge current falls until the C/10 threshold is reached, at which time the charger terminates and the LT3650 enters standby mode. The CHRG status pin follows the charger cycle and is high impedance when the charger is not actively charging. When VBAT drops below 97.5% of the full-charged float voltage, whether by battery loading or replacement of the battery, the charger automatically re-engages and starts charging. There is no provision for bad-battery detection if C/10 termination is used. Timer Termination Table 1. Status Pins State Table STATUS PINS STATE CHRG FAULT CHARGER STATUS Off Off Not Charging—Standby or Shutdown Mode Off On Bad-Battery Fault (Precondition Timeout/EOC Failure) On Off Normal Charging at C/10 or Greater On On NTC Fault (Pause) If the battery is removed from an LT3650 charger that is configured for C/10 termination, a sawtooth waveform of approximately 100mV 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 Termination The LT3650 supports a low current based termination scheme, where a battery charge cycle terminates when the current output from the charger falls to below onetenth the maximum current, as programmed with RSENSE. The C/10 threshold current corresponds to 10mV across RSENSE. This termination mode is engaged by shorting the TIMER pin to ground. When C/10 termination is used, an LT3650 charger sources battery charge current as long as the average current level remains above the C/10 threshold. As the full-charge float The LT3650 supports a timer-based termination scheme, in which a battery charge cycle is terminated after a specific amount of time elapses. Timer termination is engaged when a capacitor (CTIMER) is connected from the TIMER pin to ground. The timer cycle EOC (tEOC) occurs based on CTIMER following the relation: CTIMER = tEOC • 2.27 • 10–7 (Hours) Timer EOC is typically set to three hours, which requires a 0.68µF capacitor. The CHRG status pin continues to signal charging at a C/10 rate, regardless of which termination scheme is used. When timer termination is used, the CHRG status pin is pulled low during a charging cycle until the charger output current falls below the C/10 threshold. The charger continues to top off the battery until timer EOC, when the LT3650 terminates the charging cycle and enters standby mode. Termination at the end of the timer cycle only occurs if the charging 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 below 97.5% of the full-charge float voltage, whether by battery loading or replacement of the battery, the charger automatically re-engages and starts charging. 36508284fd 15 LT3650-8.2/LT3650-8.4 Applications Information Preconditioning and Bad-Battery Fault Battery Temperature Fault: NTC An LT3650 charger has a precondition mode, in which charge current is limited to 15% of the programmed IMAX, as set by RSENSE. The precondition current corresponds to 15mV across RSENSE. The LT3650 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 B = 3380 NTC thermistor from the NTC pin to ground. If the NTC function is not desired, leave the pin unconnected. Precondition mode is engaged while the voltage on the BAT pin is below the precondition threshold (VBAT(PRE)). Once the BAT voltage rises above the precondition threshold, normal full-current charging can commence. The LT3650 incorporates 1.5% of threshold hysteresis to prevent mode glitching. When the internal timer is used for termination, badbattery detection is engaged. 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 bad-battery 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 charging cycle is suspended, so the CHRG status pin becomes high impedance. The FAULT pin is pulled low to signal a fault detection. The RNG/SS pin is also pulled low during this fault, to accommodate a graceful restart, in the event that a soft-start function is incorporated (see the RNG/SS: Soft-Start section). Cycling the charger’s power or SHDN function initiates a new charging cycle, but an LT3650 charger does not require a reset. Once a bad-battery fault is detected, a new timer charging cycle initiates when the BAT pin exceeds the precondition threshold voltage. During a bad-battery fault, 0.5mA is sourced from the charger; removing the failed battery allows the charger output voltage to rise and initiate a charge cycle reset. As such, removing a bad battery resets the LT3650, so a new charge cycle is started by connecting another battery to the charger output. 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 LT3650 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 hysteresis that corresponds to 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 0.91k resistor will increase the effective temperature threshold to 45°C. 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 relieved. The RNG/SS pin is also pulled low during this fault, to accommodate a graceful restart in the event that a soft-start function is being incorporated (see the RNG/SS: Soft-Start section). Thermal Foldback The LT3650 contains a thermal foldback protection feature that reduces maximum charger output current if 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 charger current. In some cases, the thermal foldback protection feature can reduce charger currents below the C/10 threshold. In applications that use C/10 termination (TIMER = 0V), the LT3650 will suspend charging and enter standby mode until the overtemperature condition is relieved. 36508284fd 16 LT3650-8.2/LT3650-8.4 Applications Information Layout Considerations The LT3650 switch node has rise and fall times that are typically less than 10ns to maximize conversion efficiency. The switched node (Pin SW) trace should be kept as short as possible to minimize high frequency noise. The input capacitor (CIN) should be placed close to the IC to minimize this switching noise. Short, wide traces on these nodes also help to avoid voltage stress from inductive ringing. The BOOST decoupling capacitor should also be in close proximity to the IC to minimize inductive ringing. The SENSE and BAT traces should be routed together and kept as short as possible. Shielding these signals from switching noise with ground is recommended. High current paths and transients should be kept isolated from battery ground, to assure an accurate output voltage reference. Effective grounding can be achieved by considering switched current in the ground plane, and careful component placement and orientation can CIN effectively steer these high currents such that the battery reference does not get corrupted. Figure 9 illustrates an effective grounding scheme using component placement to control ground currents. When the switch is enabled (loop #1), current flows from the input bypass capacitor (CIN) through the switch and inductor to the battery positive terminal. When the switch is disabled (loop #2), the current to the battery positive terminal is provided from ground through the freewheeling Schottky diode (DF). In both cases, these switched currents return to ground via the output bypass capacitor (CBAT). The LT3650 packaging has been designed to efficiently remove heat from the IC via the exposed pad on the backside of the package, which is soldered to a copper footprint on the PCB. This footprint should be made as large as possible to reduce the thermal resistance of the IC case to ambient air. CBAT VBAT RSENSE 1 2 DF + LT3650 VIN SW SENSE BAT 365082 F09 Figure 9. Component Orientation Isolates High Current Paths From Sensitive Nodes 36508284fd 17 LT3650-8.2/LT3650-8.4 Typical Applications 12V to 32V 2A Charger with C/10 Termination. A Dual LT6004 Provides Thermal Foldback, Reducing Maximum Charge Current for Temperatures Higher Than 35°C D4 B340A VIN 12V TO 32V B340A VIN SW CLP BOOST 1µF 10µF LT3650 D2 SHDN D5 5.1k 0.05Ω SENSE BAT CHRG 5.1k L1 10µH CMPSH1-4 10µF FAULT NTC RNG/SS TIMER 182k (3) LT6004 CMHZ4684LTM 2.0 1.5 –INA OUTB +INA –INB V– +INB 470k CMHZ4684LTM 274k 1.0 4.99k 0.5 0 V+ OUTA 10nF (2) 3.3nF MAXIMUM CHARGE CURRENT (A) (1) Si1032R 2.5 25 30 35 40 TEMPERATURE (°C) 45 274k 50 365082 TA02 12V to 32V 2A Charger with Three Hour EOC Termination and Removable Battery Pack. The RNG/SS Pin Is Used to Reduce the Maximum Charge Current if 12V < VIN < 20V; Input UVLO = 10V. NTC Range Is Extended to +45C. The Charger Can Supply Loads Up to the Maximum Charge Current with No Battery Connected CMSH3-40MA RNG/SS Pin Foldback: ICHG(MAX) vs VIN CMSH3-40MA SW VIN 10µF MM5Z9V1ST1 (9.1V) 1µF BOOST CLP LT3650 SHDN 10µH CMPSH1-4 SENSE 0.05Ω CHRG 36k BAT 10µF FAULT RNG/SS 3k 0.1µF NTC + 100µF SYSTEM LOAD 0.91k TIMER 0.68µF B = 3380 10k + 365082 TA03a 18 MAXIMUM CHARGE CURRENT (A) VIN 12V TO 32V + B = 3800 10k 365082 TA02b 2.0 1.5 1.0 0.5 0 10 12 14 18 16 VIN 20 22 32 365082 TA03b 36508284fd LT3650-8.2/LT3650-8.4 Package Description Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. DD Package 12-Lead Plastic DFN (3mm × 3mm) (Reference LTC DWG # 05-08-1725 Rev A) 0.70 ±0.05 3.50 ±0.05 2.10 ±0.05 2.38 ±0.05 1.65 ±0.05 PACKAGE OUTLINE 0.25 ±0.05 0.45 BSC 2.25 REF RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED 3.00 ±0.10 (4 SIDES) R = 0.115 TYP 7 0.40 ±0.10 12 2.38 ±0.10 1.65 ±0.10 PIN 1 NOTCH R = 0.20 OR 0.25 × 45° CHAMFER PIN 1 TOP MARK (SEE NOTE 6) 6 0.200 REF 1 0.23 ±0.05 0.45 BSC 0.75 ±0.05 2.25 REF 0.00 – 0.05 (DD12) DFN 0106 REV A BOTTOM VIEW—EXPOSED PAD NOTE: 1. DRAWING IS NOT A JEDEC PACKAGE OUTLINE 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE 5. EXPOSED PAD AND TIE BARS SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE 36508284fd 19 LT3650-8.2/LT3650-8.4 Package Description Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. MSE Package 12-Lead Plastic MSOP, Exposed Die Pad (Reference LTC DWG # 05-08-1666 Rev F) BOTTOM VIEW OF EXPOSED PAD OPTION 2.845 ±0.102 (.112 ±.004) 5.23 (.206) MIN 2.845 ±0.102 (.112 ±.004) 0.889 ±0.127 (.035 ±.005) 6 1 1.651 ±0.102 (.065 ±.004) 1.651 ±0.102 3.20 – 3.45 (.065 ±.004) (.126 – .136) 12 0.65 0.42 ±0.038 (.0256) (.0165 ±.0015) BSC TYP RECOMMENDED SOLDER PAD LAYOUT 0.254 (.010) 0.35 REF 4.039 ±0.102 (.159 ±.004) (NOTE 3) 0.12 REF DETAIL “B” CORNER TAIL IS PART OF DETAIL “B” THE LEADFRAME FEATURE. FOR REFERENCE ONLY 7 NO MEASUREMENT PURPOSE 0.406 ±0.076 (.016 ±.003) REF 12 11 10 9 8 7 DETAIL “A” 0° – 6° TYP 3.00 ±0.102 (.118 ±.004) (NOTE 4) 4.90 ±0.152 (.193 ±.006) GAUGE PLANE 0.53 ±0.152 (.021 ±.006) DETAIL “A” 1.10 (.043) MAX 0.18 (.007) SEATING PLANE 0.22 – 0.38 (.009 – .015) TYP 1 2 3 4 5 6 0.650 (.0256) BSC NOTE: 1. DIMENSIONS IN MILLIMETER/(INCH) 2. DRAWING NOT TO SCALE 3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX 6. EXPOSED PAD DIMENSION DOES INCLUDE MOLD FLASH. MOLD FLASH ON E-PAD SHALL NOT EXCEED 0.254mm (.010") PER SIDE. 0.86 (.034) REF 0.1016 ±0.0508 (.004 ±.002) MSOP (MSE12) 0911 REV F 36508284fd 20 LT3650-8.2/LT3650-8.4 Revision History (Revision history begins at Rev D) REV DATE DESCRIPTION D 12/12 Added new Battery Bias Current curve PAGE NUMBER 5 36508284fd 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. 21 LT3650-8.2/LT3650-8.4 Typical Application 12V to 32V 1.5A PowerPath Charger with C/10 Termination and 1A Input Supply Limit. Status Pins Use LED Indicators INPUT SUPPLY 12V TO 32V 1A B240A SYSTEM LOAD 0.05Ω B240A VIN SW CLP BOOST B240A 1µF 402k LT3650 47k 10k 10k 10µF 15µH BAS40 SHDN SENSE CHRG BAT FAULT NTC TIMER RNG/SS 0.068Ω 10µF 365082 TA04 + 0.1µF B = 3380 10k Related Parts PART NUMBER DESCRIPTION COMMENTS LT1511 3A Constant-Current/Constant-Voltage Battery Charger High Efficiency, Minimum External Components to Fast Charge Lithium, NIMH and NiCd Batteries, 24-Lead SO Package LT1513 SEPIC Constant or Programmable Current/ Constant-Voltage Battery Charger Charger Input Voltage May Be Higher, Equal to or Lower Than Battery Voltage, 500kHz Switching Frequency, DD-Pak and TO-220 Packages LT1571 1.5A Switching Charger 1- or 2-Cell Li-Ion, 500kHz or 200kHz Switching Frequency, Termination Flag, 16- and 28-Lead SSOP Packages LTC1729 Li-Ion Battery Charger Termination Controller Trickle Charge Preconditioning, Temperature Charge Qualification, Time or Charge Current Termination, Automatic Charger and Battery Detection, and Status Output, MS8 and SO-8 Packages LT1769 2A Switching Charger Constant-Current/Constant-Voltage Switching Regulator, Input Current Limiting Maximizes Charge Current, 20-Lead TSSOP and 28-Lead SSOP Packages LT3650-4.1/ LT3650-4.2 High Voltage 2-Amp Monolithic 1-Cell Li-Ion Battery Charger VIN: 4.75 to 32V (40V Absolute Maximum), FSW: 1MHz, User-Selectable C/10 or Programmable Termination Timer, 3mm × 3mm DFN-12 Package LTC4002 Standalone Li-Ion Switch Mode Battery Charger Complete Charger for 1- or 2-Cell Li-Ion Batteries, Onboard Timer Termination, Up to 4A Charge Current, 10-Lead DFN and SO-8 Packages LTC4006 Small, High Efficiency, Fixed Voltage Li-Ion Battery Charger with Termination Complete Charger for 2-, 3- or 4-Cell Li-Ion Batteries, AC Adapter Current Limit and Thermistor Sensor, 16-Lead Narrow SSOP Package LTC4007 High Efficiency, Programmable Voltage Battery Charger with Termination Complete Charger for 3- or 4-Cell Li-Ion Batteries, AC Adapter Current Limit, Thermistor Sensor and Indicator Outputs, 24-Lead SSOP Package LTC4008 4A, High Efficiency, Multi-Chemistry Battery Charger Complete Charger for 2- to 6-Cell Li-Ion Batteries or 4- to 18-Cell Nickel Batteries, Up to 96% Efficiency, 20-Lead SSOP Package LTC4009/ LTC4009-1/ LTC4009-2 4A, High Efficiency, Multi-Chemistry Battery Charger Constant-Current/Constant-Voltage Switching Regulator Charger, Resistor Voltage/ Current Programming, AC Adapter Current Limit and Thermistor Sensor and Indicator Outputs 1- to 4-Cell Li, Up to 18-Cell Ni, SLA and Supercap Compatible; 4mm × 4mm QFN-20 Package, LTC4009-1 Version for 4.1V Float Voltage Li-Ion, LTC4009-2 Version for 4.2V Float Voltage Li-Ion Cells. 36508284fd 22 Linear Technology Corporation LT 1212 REV D • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com ©LINEAR TECHNOLOGY CORPORATION 2009
LT3650EMSE-8.4#PBF 价格&库存

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LT3650EMSE-8.4#PBF
  •  国内价格
  • 1+16.35390
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