APPLICATIO S. LTC /LTC4068X-4.2 Standalone Linear Li-Ion Battery Charger with Programmable Termination DESCRIPTIO FEATURES TYPICAL APPLICATIO

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1 FEATURES Programmable Charge Current Up to 9mA Complete Linear Charger in DFN Package No MOSFET, Sense Resistor or Blocking Diode Required Thermal Regulation Maximizes Charge Rate Without Risk of Overheating* Charges Directly from a USB Port Programmable Charge Current Termination Preset.V Charge Voltage with ±% Accuracy Charge Current Monitor Output for Gas Gauging* Automatic Recharge Charge Status Output AC Present Output.9V Trickle Charge Threshold (LTC8) Available Without Trickle Charge (LTC8X) Soft-Start Limits nrush Current Low Profile (3mm 3mm.7mm) DFN Package APPLCATO S U Cellular Telephones, PDAs, MP3 Players Bluetooth Applications LTC8-./LTC8X-. Standalone Linear Li-on Battery Charger with Programmable Termination DESCRPTO U The LTC 8 is a complete constant-current/constantvoltage linear charger for single cell lithium-ion batteries. ts DFN package and low external component count make the LTC8 ideally suited for portable applications. Furthermore, the LTC8 is designed to work within USB power specifications. No external sense resistor or external blocking diode are required due to the internal MOSFET architecture. Thermal feedback regulates the charge current to limit the die temperature during high power operation or high ambient temperature conditions. The charge voltage is fixed at.v and the charge current is programmed with a resistor. The LTC8 terminates the charge cycle when the charge current drops below the programmed termination threshold after the final float voltage is reached. When the input supply (wall adapter or USB supply) is removed, the LTC8 enters a low current state dropping the battery drain current to less than µa. Other features include charge current monitor, undervoltage lockout, automatic recharge and status pins to indicate charge termination and the presence of adequate input voltage., LTC and LT are registered trademarks of Linear Technology Corporation. Protected by U.S. Patents, including 8. TYPCAL APPLCATO V N.V TO.V µf V CC LTC8-. CHRG ACPR EN U Single Cell Li-on Battery Charger with C/ Termination.k ma 8Ω -CELL Li-on TERY 8 TA CHARGE CURRENT (ma) Complete Charge Cycle (7mAh Battery) 7 3 CONSTANT CURRENT TME (HOURS) CONSTANT VOLTAGE 8 TA θ JA C/W R.k R 8Ω 3. T A C TERY VOLTAGE (V) 8fa

2 LTC8-./LTC8X-. ABSOLUTE AX U RAT GS W W W (Note ) nput Supply Voltage (V CC )....3V to V,....3V to V CC.3V....3V to 7V CHRG, ACPR, EN....3V to V Short-Circuit Duration... Continuous Pin Current... A Pin Current... ma Maximum Junction Temperature... C Operating Temperature Range (Note ).. C to 8 C Storage Temperature Range... C to C U U U W PACKAGE/ORDER FOR ATO CHRG 3 TOP VEW 9 DD PACKAGE 8-LEAD (3mm 3mm) PLASTC DFN T JMAX C, θ JA C/W (NOTE 3) EXPOSED PAD S GROUND (PN 9) MUST BE SOLDERED TO PCB 8 7 EN ACPR V CC ORDER PART NUMBER LTC8EDD-. LTC8XEDD-. DD PART MARKNG LBHZ LBQB Consult LTC Marketing for parts specified with wider operating temperature ranges. ELECTRCAL CHARACTERSTCS The denotes specifications which apply over the full operating temperature range, otherwise specifications are at T A C., unless otherwise noted. SYMBOL PARAMETER CONDTONS MN TYP MAX UNTS V CC nput Supply Voltage.. V CC nput Supply Current Charge Mode (Note ), R k. ma Standby Mode (Charge Terminated) µa Shutdown Mode (EN V, V CC < V µa or V CC < V UV ) V FLOAT Regulated Output (Float) Voltage C T A 8 C,.3V < V CC <.V.8.. V Pin Current R k, Current Mode 9 ma R k, Current Mode 3 ma Standby Mode, V.V. µa Shutdown Mode (EN V, V CC < V or ± ± µa V CC < V UV ) Sleep Mode, V CC V ± ± µa TRKL Trickle Charge Current V < V TRKL, R k (Note ) 3 ma V TRKL Trickle Charge Threshold Voltage R k, V Rising (Note ) V V TRHYS Trickle Charge Hysteresis Voltage R k (Note ) 8 mv V UV V CC Undervoltage Lockout Voltage From V CC Low to High V V UVHYS V CC Undervoltage Lockout Hysteresis 3 mv V EN(L) EN Pin nput Low Voltage..7 V V EN(H) EN Pin nput High Voltage.7 V R EN EN Pin Pull-Down Resistor. MΩ V ASD V CC V Lockout Threshold V CC from Low to High 7 mv V CC from High to Low 3 mv Charge Termination Current Threshold R k 9 ma R k 7.. ma V Pin Voltage R k, Current Mode.93.7 V V CHRG CHRG Pin Output Low Voltage CHRG ma.3. V V ACPR ACPR Pin Output Low Voltage ACPR ma.3. V V RECHRG Recharge Battery Threshold Voltage V FLOAT V RECHRG, C T A 8 C mv 8fa

3 LTC8-./LTC8X-. ELECTRCAL CHARACTERSTCS The denotes specifications which apply over the full operating temperature range, otherwise specifications are at T A C., unless otherwise noted. SYMBOL PARAMETER CONDTONS MN TYP MAX UNTS T LM Junction Temperature in Constant C Temperature Mode R ON Power FET ON Resistance mω (Between V CC and ) t SS Soft-Start Time to V/R µs t RECHARGE Recharge Comparator Filter Time V High to Low.7. ms t Termination Comparator Filter Time Drops Below Charge Termination Threshold µs Note : Absolute Maximum Ratings are those values beyond which the life of the device may be impaired. Note : The LTC8E-./LTC8XE-. are guaranteed to meet performance specifications from C to 7 C. Specifications over the C to 8 C operating temperature range are assured by design, characterization and correlation with statistical process controls. Note 3: Failure to solder the exposed backside of the package to the PC board will result in a thermal resistance much higher than C/W. Note : Supply current includes pin current and pin current (approximately µa each) but does not include any current delivered to the battery through the pin (approximately ma). Note : This parameter is not applicable to the LTC8X. TYPCAL PERFOR A CE CHARACTERSTCS UW V (V) Pin Voltage vs Supply Voltage (Constant Current Mode) V V T A C R k V (V) Pin Voltage vs Temperature V V R k (ma) 3 Charge Current vs Pin Voltage T A C R k R k.98.. V CC (V) V (V). 8 G 8 G 8 G3 8fa 3

4 LTC8-./LTC8X-. TYPCAL PERFOR A CE CHARACTERSTCS UW VFLOAT (V) Regulated Output (Float) Voltage vs Charge Current T A C R.k V FLOAT (V) Regulated Output (Float) Voltage vs Temperature R k VFLOAT (V) Regulated Output (Float) Voltage vs Supply Voltage T A C R k. 3 (ma) V CC (V). 7 8 G 8 G 8 G CHRG Pin -V Curve (Pull-Down State) ACPR Pin -V Curve (Pull-Down State) Trickle Charge Current vs Temperature 3 T A C T A C 3 T A C T A C V.V R k LTC8 ONLY CHRG (ma) T A 9 C ACPR (ma) T A 9 C TRKL (ma) 3 V V 3 7 V CHRG (V) V V 3 7 V ACPR (V) R k 7 8 G7 8 G8 8 G9 Trickle Charge Current vs Supply Voltage Trickle Charge Threshold Voltage vs Temperature Charge Current vs Battery Voltage TRKL (ma) 3 V.V T A C R k R k.. V CC (V) LTC8 ONLY. 7 V TRKL (V) R k LTC8 ONLY 7 (ma) LTC8 ONLY 3. θ JA C/W R k V (V) 8 G 8 G 8 G 8fa

5 TYPCAL PERFOR A CE CHARACTERSTCS UW LTC8-./LTC8X-. Charge Current vs Supply Voltage R k Charge Current vs Ambient Temperature ONSET OF THERMAL REGULATON R k (ma) 3 V V T A C θ JA C/W (ma) 3 V V θ JA C/W R k R k.. V CC (V) G3 8 G 7 Power FET ON Resistance vs Temperature V CC.V ma R k.. Recharge Threshold Voltage vs Temperature R k RDS(ON) (mω) VRECHRG (V) G7 8 G P FU CTO S U U U (Pin ): Charge Termination Program. The charge termination current threshold current is programmed by connecting a % resistor, R, to ground. The current threshold, is set by the following formula: V V, R R (Pin ): Charge Current Output. Provides charge current to the battery from the internal P-channel MOSFET, and regulates the final float voltage to.v. An internal precision resistor divider from this pin sets the float voltage. This divider is disconnected in shutdown mode to minimize current drain from the battery. CHRG (Pin 3): Charge Status Open-Drain Output. When the battery is charging, the CHRG pin is pulled low by an internal N-channel MOSFET. When the charge cycle is completed, CHRG becomes high impedance. (Pins, 9): Ground/Exposed Pad. The exposed backside package pad (Pin 9) is electrical ground and must be soldered to the PC board for maximum heat transfer. 8fa

6 LTC8-./LTC8X-. P FU CTO S U U U (Pin ): Charge Current Program and Charge Current Monitor. Charge current is programmed by connecting a % resistor, R, to ground. When charging in constant-current mode, this pin servos to V. n all modes, the voltage on this pin can be used to measure the charge current using the following formula: (V /R ) This pin is clamped to approximately.v. Driving this pin to voltages beyond the clamp voltage can draw large currents and should be avoided. V CC (Pin ): Positive nput Supply Voltage. Provides power to the charger. V CC can range from.v to.v. This pin should be bypassed with at least a µf capacitor. When V CC is within mv of the pin voltage, the LTC8 enters shutdown mode dropping the battery drain current to less than µa. ACPR (Pin 7): Power Supply Status Open-Drain Output. When V CC is greater than the undervoltage lockout threshold and at least mv above V, the ACPR pin is pulled to ground; otherwise, the pin is high impedance. EN (Pin 8): Enable nput. A logic high on the EN pin will put the LTC8 into shutdown mode where the battery drain current is reduced to less than µa and the supply current is reduced to less than µa. A logic low or floating the EN pin (allowing an internal MΩ pull-down resistor to pull this pin low) enables charging. BLOCK DAGRA W V CC C T DE T A MA µa R 7 ACPR VA R 3 CHRG CA REF.V R3 CHARGE ACPR LOGC * C V R.V R EN SHDN 8 EN C*.9V TO *TRCKLE CHARGE DSABLED ON THE LTC8X, 9 R R 8 BD 8fa

7 LTC8-./LTC8X-. OPERATO U The LTC8 is a single cell lithium-ion battery charger using a constant-current/constant-voltage algorithm. t can deliver up to 9mA of charge current (using a good thermal PCB layout) with a final float voltage accuracy of ±%. The LTC8 includes an internal P-channel power MOSFET and thermal regulation circuitry. No blocking diode or external current sense resistor is required; thus, the basic charger circuit requires only two external components. Furthermore, the LTC8 is capable of operating from a USB power source. Normal Charge Cycle A charge cycle begins when the voltage at the V CC pin rises above the UVLO threshold level and a % program resistor is connected from the pin to ground. f the pin is less than.9v, the charger enters trickle charge mode. n this mode, the LTC8 supplies approximately /th the programmed charge current to bring the battery voltage up to a safe level for full current charging. (Note: The LTC8X does not include this trickle charge feature.) When the pin voltage rises above.9v, the charger enters constant-current mode where the programmed charge current is supplied to the battery. When the pin approaches the final float voltage (.V), the LTC8 enters constant-voltage mode and the charge current begins to decrease. When the charge current drops to the programmed termination threshold (set by the external resistor R ), the charge cycle ends. Programming Charge Current The charge current is programmed using a single resistor from the pin to ground. The charge current out of the pin is times the current out of the pin. The program resistor and the charge current are calculated using the following equations: R V V, CHG R CHG Charge current out of the pin can be determined at any time by monitoring the pin voltage and using the following equation: V R Programming Charge Termination The charge cycle terminates when the charge current falls below the programmed termination threshold. This threshold is set by connecting an external resistor, R, from the pin to ground. The charge termination current threshold ( ) is set by the following equation: V CHG R V, R R R The termination condition is detected by using an internal filtered comparator to monitor the pin. When the pin voltage drops below mv * for longer than t (typically ms), charging is terminated. The charge current is latched off and the LTC8 enters standby mode where the input supply current drops to µa. (Note: Termination is disabled in trickle charging and thermal limiting modes.) can be set to be /th of CHG by shorting the pin to the pin, thus eliminating the need for external resistor R. When configured in this way, is always set to CHG /, and the programmed charge current is set by the equation: CHG V V, R R CHG When charging, transient loads on the pin can cause the pin to fall below mv for short periods of time before the DC charge current has dropped to % of the programmed value. The ms filter time (t ) on the termination comparator ensures that transient loads of this nature do not result in premature charge cycle termination. Once the average charge current drops below the programmed termination threshold, the LTC8 terminates the charge cycle and ceases to provide any current out of the pin. n this state, any load on the pin must be supplied by the battery. The LTC8 constantly monitors the pin voltage in standby mode. f this voltage drops below the.v recharge * Any external sources that hold the pin above mv will prevent the LTC8 from terminating a charge cycle. ** These equations apply only when the pin is shorted to the pin. ** 8fa 7

8 LTC8-./LTC8X-. OPERATO U threshold (V RECHRG ), another charge cycle begins and charge current is once again supplied to the battery. To manually restart a charge cycle when in standby mode, the input voltage must be removed and reapplied or the charger must be shut down and restarted using the EN pin. Figure shows the state diagram of a typical charge cycle. POWER ON EN DRVEN LOW OR UVLO CONDTON STOPS SHUTDOWN MODE CC DROPS TO <µa CHRG: Hi-Z EN DRVEN HGH OR UVLO CONDTON <.9V TRCKLE CHARGE MODE /TH FULL CURRENT CHRG: STRONG PULL-DOWN >.9V LTC8 ONLY CHARGE MODE >.9V FULL CURRENT CHRG: STRONG PULL-DOWN < mv STANDBY MODE NO CHARGE CURRENT CHRG: Hi-Z 8 F.9V < <.V Figure. State Diagram of a Typical Charge Cycle Charge Status ndicator (CHRG) The charge status output has two states: pull-down and high impedance. The pull-down state indicates that the LTC8 is in a charge cycle. Once the charge cycle has terminated or the LTC8 is disabled, the pin state becomes high impedance. Power Supply Status ndicator (ACPR) The power supply status output has two states: pull-down and high impedance. The pull-down state indicates that V CC is above the UVLO threshold (3.8V) and is also mv above the battery voltage. f these conditions are not met, the ACPR pin is high impedance indicating that the LTC8 is unable to charge the battery. Thermal Limiting An internal thermal feedback loop reduces the programmed charge current if the die temperature attempts to rise above a preset value of approximately C. This feature protects the LTC8 from excessive temperature and allows the user to push the limits of the power handling capability of a given circuit board without risk of damaging the LTC8. The charge current can be set according to typical (not worst case) ambient temperature with the assurance that the charger will automatically reduce the current in worst-case conditions. DFN power considerations are discussed further in the Applications nformation section. Undervoltage Lockout (UVLO) An internal undervoltage lockout circuit monitors the input voltage and keeps the charger in shutdown mode until V CC rises above the undervoltage lockout threshold. The UVLO circuit has a built-in hysteresis of mv. Furthermore, to protect against reverse current in the power MOSFET, the UVLO circuit keeps the charger in shutdown mode if V CC falls to within 3mV of the voltage. f the UVLO comparator is tripped, the charger will not come out of shutdown mode until V CC rises mv above the voltage. Manual Shutdown At any point in the charge cycle, the LTC8 can be put into shutdown mode by driving the EN pin high. This reduces the battery drain current to less than µa and the supply current to less than µa. When in shutdown mode, the CHRG pin is in the high impedance state. A new charge cycle can be initiated by driving the EN pin low. An internal resistor pull-down on this pin forces the LTC8 to be enabled if the pin is allowed to float. Automatic Recharge Once the charge cycle is terminated, the LTC8 continuously monitors the voltage on the pin using a comparator with a ms filter time (t RECHARGE ). A charge cycle restarts when the battery voltage falls below.v (which corresponds to approximately 8% to 9% battery capacity). This ensures that the battery is kept at, or near, a fully 8 8fa

9 LTC8-./LTC8X-. APPLCATO S FOR ATO U W U U charged condition and eliminates the need for periodic charge cycle initiations. The CHRG output enters a pulldown state during recharge cycles. f the battery is removed from the charger, a sawtooth waveform of approximately mv appears at the charger output. This is caused by the repeated 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 the sawtooth is dependent on the amount of output capacitance. Stability Considerations The constant-voltage mode feedback loop is stable without an output capacitor, provided a battery is connected to the charger output. With no battery present, an output capacitor on the pin is recommended to reduce ripple voltage. When using high value, low ESR ceramic capacitors, it is recommended to add a Ω resistor in series with the capacitor. No series resistor is needed if tantalum capacitors are used. n constant-current mode, the pin is in the feedback loop, not the battery. The constant-current mode stability is affected by the impedance at the pin. With no additional capacitance on the pin, the charger is stable with program resistor values as high as k; however, additional capacitance on this node reduces the maximum allowed program resistor. The pole frequency at the pin should be kept above khz. Therefore, if the pin is loaded with a capacitance, C, the following equation can be used to calculate the maximum resistance value for R : R π C Average, rather than instantaneous charge current may be of interest to the user. For example, if a switching power supply operating in low current mode is connected in parallel with the battery, the average current being pulled out of the pin is typically of more interest than the instantaneous current pulses. n such a case, a simple RC filter can be used on the pin to measure the average battery current, as shown in Figure. A k resistor has been added between the pin and the filter capacitor to ensure stability. LTC8-. k R C FLTER 8 F CHARGE CURRENT MONTOR CRCUTRY Figure. solating Capacitive Load on Pin and Filtering Power Dissipation t is not necessary to design for worst-case power dissipation scenarios because the LTC8 automatically reduces the charge current during high power conditions. The conditions that cause the LTC8 to reduce charge current through thermal feedback can be approximated by considering the power dissipated in the C. Nearly all of this power dissipation is generated by the internal MOSFET this is calculated to be approximately: P D (V CC V ) where P D is the power dissipated, V CC is the input supply voltage, V is the battery voltage and is the charge current. The approximate ambient temperature at which the thermal feedback begins to protect the C is: T A C P D θ JA T A C (V CC V ) θ JA Example: An LTC8 operating from a V supply is programmed to supply 8mA full-scale current to a discharged Li-on battery with a voltage of 3.3V. Assuming θ JA is C/W (see Thermal Considerations), the ambient temperature at which the LTC8 will begin to reduce the charge current is approximately: T A C (V 3.3V) (8mA) C/W T A C.3W C/W C 8 C T A C 8fa 9

10 LTC8-./LTC8X-. APPLCATO S FOR ATO The LTC8 can be used above C ambient but the charge current will be reduced from the programmed 8mA. The approximate current at a given ambient temperature can be approximated by: C TA V V θ ( ) CC JA Using the previous example with an ambient temperature of C, the charge current will be reduced to approximately: C C C V 3. 3V C/ W 8 CA / ( ) 7mA U W U U Moreover, when thermal feedback reduces the charge current the voltage at the pin is also reduced proportionally as discussed in the Operation section. t is important to remember that LTC8 applications do not need to be designed for worst-case thermal conditions since the C will automatically reduce power dissipation when the junction temperature reaches approximately C. Thermal Considerations n order to deliver maximum charge current under all conditions, it is critical that the exposed metal pad on the backside of the LTC8 package is soldered to the PC board ground. Correctly soldered to a mm doublesided oz copper board, the LTC8 has a thermal resistance of approximately C/W. Failure to make thermal contact between the exposed pad on the backside of the package and the copper board will result in thermal resistances far greater than C/W. As an example, a correctly soldered LTC8 can deliver over 8mA to a battery from a V supply at room temperature. Without a good backside thermal connection, this number will drop considerably. V CC Bypass Capacitor Many types of capacitors can be used for input bypassing; however, caution must be exercised when using multilayer ceramic capacitors. Because of the self-resonant and high Q characteristics of some types of ceramic capacitors, high voltage transients can be generated under some start-up conditions such as connecting the charger input to a live power source. Adding a.ω resistor in series with an XR ceramic capacitor will minimize start-up voltage transients. For more information, see Application Note 88. Charge Current Soft-Start The LTC8 includes a soft-start circuit to minimize the inrush current at the start of a charge cycle. When a charge cycle is initiated, the charge current ramps from zero to full-scale current over a period of approximately µs. This has the effect of minimizing the transient current load on the power supply during start-up. USB and Wall Adapter Power The LTC8 allows charging from both a wall adapter and a USB port. Figure 3 shows how to combine wall adapter and USB power inputs. A P-channel MOSFET, MP, is used to prevent back conducting into the USB port when a wall adapter is present and a Schottky diode, D, is used to prevent USB power loss through the k pulldown resistor. Typically a wall adapter can supply more current than the ma-limited USB port. Therefore, an N-channel MOSFET, MN, and an extra 3.3k program resistor are used to increase the charge current to 8mA when the wall adapter is present. The charge termination threshold remains fixed at 8mA. V WALL ADAPTER 8mA CHG USB POWER ma CHG MP k D, 9 LTC8-. V CC 3.3k MN k.k CHG SYSTEM LOAD Li-on TERY 8 F3 Figure 3. Combining Wall Adapter and USB Power 8fa

11 LTC8-./LTC8X-. APPLCATO S FOR ATO U W U U Reverse Polarity nput Voltage Protection n some applications, protection from reverse polarity voltage on V CC is desired. f the supply voltage is high enough, a series blocking diode can be used. n other cases, where the voltage drop must be kept low, a P-channel MOSFET can be used (as shown in Figure ). V N DRAN-BULK DODE OF FET VCC LTC8 8 F Figure. Low Loss nput Reverse Polarity Protection PACKAGE DESCRPTO U DD Package 8-Lead Plastic DFN (3mm 3mm) (Reference LTC DWG # -8-98).7 ±. 3. ±.. ±.. ±. ( SDES) PACKAGE OUTLNE.8 ±.. BSC.38 ±. ( SDES) RECOMMENDED SOLDER PAD PTCH AND DMENSONS R. TYP 8.38 ±. PN TOP MARK 3. ±. ( SDES). ±. ( SDES). REF.7 ±....8 ±..38 ±. ( SDES) BOTTOM VEW EXPOSED PAD NOTE:. DRAWNG TO BE MADE A JEDEC PACKAGE OUTLNE M-9 VARATON OF (WEED-). ALL DMENSONS ARE N MLLMETERS 3. DMENSONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT NCLUDE MOLD FLASH. MOLD FLASH, F PRESENT, SHALL NOT EXCEED.mm ON ANY SDE. EXPOSED PAD SHALL BE SOLDER PLATED. BSC (DD8) DFN 3 nformation 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. 8fa

12 LTC8-./LTC8X-. TYPCAL APPLCATO S V N V U Full Featured Single Cell Li-on Charger µf k k V ma CC 7 ACPR 3 CHRG LTC8-. k 8 EN k, 9 -CELL Li-on TERY TA3 µf Li-on Battery Charger with Reverse Polarity nput Protection V WALL ADAPTER µf 8 V CC LTC8-. EN, 9 ma k -CELL Li-on TERY 8 TA USB/Wall Adapter Power Li-on Charger V WALL ADAPTER USB POWER k µf LTC8-. V CC, 9.k k -CELL Li-on TERY ma/ ma µc 8 TA RELATED PARTS PART NUMBER DESCRPTON COMMENTS LTC73 Lithium-on Linear Battery Charger Controller Simple Charger uses External FET, Features Preset Voltages, C/ Charger Detection and Programmable Timer, nput Power Good ndication LTC733 Monolithic Lithium-on Linear Battery Charger Standalone Charger with Programmable Timer, Up to.a Charge Current LTC73 Lithium-on Linear Battery Charger in ThinSOT TM Simple ThinSOT Charger, No Blocking Diode, No Sense Resistor Needed LTC73L Lithium-on Linear Battery Charger in ThinSOT Low Current Version of LTC73; ma CHRG 8mA LTC998 Lithium-on Low Battery Detector % Accurate.µA Quiescent Current, SOT-3 LTC7 A Multicell Li-on Battery Charger Standalone Charger, V V N 8V, Up to 9% Efficiency, ±.8% Charging Voltage Accuracy LTC Lithium-on Linear Battery Charger Controller C/ Charger Detection and Programmable Timer, Thermistor nterface LTC Monolithic Lithium-on Battery Pulse Charger No Blocking Diode or External Power FET Required,.A Charge Current LTC3 USB Compatible Monolithic Li-on Battery Charger Standalone Charger with Programmable Timer, Up to.a Charge Current LTC Standalone Linear Li-on Battery Charger Thermal Regulation Prevents Overheating, C/ Termination, in ThinSOT C/ ndicator, Up to 8mA Charge Current LTC7 Li-on Linear Battery Charger Up to 8mA Charge Current, Thermal Regulation, ThinSOT Package LTC8 Standalone Li-on Linear Charger in DFN Up to 9mA Charge Current, Kelvin Sense for High Accuracy, LTC8X C/ Charge Termination LTC USB Power Manager For Simultaneous Operation of USB Peripheral and Battery Charging from USB Port, Keeps Current Drawn from USB Port Constant, Keeps Battery Fresh, Use with the LTC3, LTC733, or LTC LTC Low Loss PowerPath TM Controller in ThinSOT Automatic Switching Between DC Sources, Load Sharing, LTC Replaces ORing Diodes ThinSOT and PowerPath are trademarks of Linear Technology Corporation. Linear Technology Corporation 3 McCarthy Blvd., Milpitas, CA (8) 3-9 FAX: (8) fa LT/TP 9 K REV A PRNTED N USA LNEAR TECHNOLOGY CORPORATON