SC802/SC802A Fully Integrated Lithium-Ion Battery Charger System with Timer POWER MANAGEMENT Description Features Fully integrated charger with FET pass transistor, The SC802 is a fully integrated, single cell, constant-current/constant-voltage Lithium-Ion\Lithium Polymer battery charger. With an integrated timer and complete charge control algorithm, the SC802 is well suited for stand-alone charger applications. The SC802 contains programmable pre-charge, fast-charge, and termination current settings. The SC802 can be programmed to terminate charge based on the output current or the timeout of the programmable timer. The fast charge current is typically set with an external resistor but can be modified with the analog fast charge input to allow a Power Management Controller to control the fastcharge current setting via DAC. The 14V input voltage range of the SC802 eliminates additional protection circuitry required by other 5V chargers in the event of faulty adapters. Reference ground and battery sense inputs are provided to allow Kelvin connections to eliminate IR voltage drops during charging. The output voltage to the battery is controlled to within 1% of the programmed voltage for either 4.1V or 4.2V. The SC802 can also function as a general purpose current source or as a current source for charging nickelcadmium (NiCd) and nickel-metal-hydride (NiMH) batteries using NTC termination. Applications The SC802A version of the device is optimized for high termination current applications. All descriptions and text refering to the SC802 also apply to the SC802A unless otherwise noted. Typical Application Circuit 14 13 3 7 4 8 6 5 CHARGER VIN R3 R C1 1uF RT1 THERMISTOR SC802 VCC CPB VCC CHRGB RTIM IPRGM EN/NTC VPRGM ITERM BSEN BIPB VOUT GND VOUT RFGND AFC Cellular phones PDA’s Handheld meters Charging stations Handheld computers Digital cameras Programmable current source 11 10 12 2 1 16 15 9 CHARGE R4 R2 R1 ADC Iset BATTERY t June 13, 2005 reverse-blocking diode, sense resistor, timer, and thermal protection Complete voltage ranges of 4.1V, 4.2V & adjustable Programmable precharge, fastcharge & termination current Battery voltage controlled to 1% accuracy Soft-start for glitch-free adaptor plug-in Up to 1A continuous charge current Charge current monitor output for microcontroller or ADC interface Input voltage range from 4.3V to 14V 0.1μA battery drain current in shutdown and monitor modes Operates without a battery in regulated LDO mode Small 4mm x 4mm 16 lead MLP package NTC thermistor sense input Adjustable 6 Hour programmable charge timer Over current protection in all charging modes Over voltage protection Remote Kelvin sensing at the battery terminals ADC input control capable Status output communicates charging and end of charge cycle Charges Li-Ion, Li-Polymer, NiCd and NiMH Batteries 1 C2 2.2uF R5 1K CHARGER PRESENT R6 1K www.semtech.com SC802/SC802A POWER MANAGEMENT Prelimi-Ratings Absolute Maximum Exceeding nary the specifications below may result in permanent damage to the device, or device malfunction. Operation outside of the parameters specified in the Electrical Characteristics section is not implied. Pin Combination Symbol Maximum U n i ts VCC, EN to GN D -0.3 to 14.0 V VOUT, Rtime, AFC, VPRGM, IPRGM, CPB, CHRGB, ITERM, BIPB, to GN D -0.3 to +6.0 V REFGN D to GN D -0.3 to 0.3 V Power Dissip ation MLP (Derate 20mW/ °C above 85°C) Pd 2 W Thermal Imp edance, Junction to Ambient T JA 50* °C/W Thermal Imp edance, Junction to Case T JC 3 °C/W Junction Temp erature TJ 150 °C Op erating Ambient Temp erature Range TA -40 to +85 °C Peak IR Reflow temp erature, soldering 20s-40s T LE A D 260 °C Storage Temp erature Range TSTG -65 to 150 °C VOUT shor t to GN D Continuous * Tied to PCB with 1 Square Inch, 2 Ounce Copper, using JESD 51 Standard. Electrical Characteristics Unless otherwise noted: VCC = 4.75V - 5.25V Parameter Symbol 25oC C onditions Min Typ TA (-40oC to +85oC ) Max Min Max U nits Input Wi thstand Voltage VC C 4.3 14 V Operati ng Voltage VOP 4.3 6.5* V 3.7 4.3 V 4.0 VC C UVLO Ri si ng Threshold VTUVLOR VC C UVLO Hysteresi s VTUVLOH VC C OVP Ri si ng Threshold VTOVPR 6.8 6.5 7.5 V VC C OVP Falli ng Threshold VTOVPF 6.5 6.1 7.1 V VC C OVP Hysteresi s VTOVPH VC C Falli ng Hysteresi s 300 200 500 mV Operati ng C urrent IC CDIS Shutdown Mode C HRGB,C PB off 2.6 IC C CHG C hargi ng Mode C HRGB, C PB off 2.4 1 3.5 IC C LDO LD O Mode C HRGB, C PB off 16 8 23 VC C Falli ng Hysteresi s 40 mV mA * Maximum Vsupply as defined in EIA/JEDEC Standard No. 78, paragraph 2.11. © 2005 Semtech Corp. 2 www.semtech.com SC802/SC802A POWER MANAGEMENT Electrical Characteristics (Cont.) Unless otherwise noted: VCC = 4.75V - 5.25V Parameter Symbol Conditions 25 oC Min Battery Leakage Current (Vout and BSEN) Typ ILeakBAT VCC = 0V, VOUT = BSEN = 4.5V 0.1 Regulated Voltage VBAT2 VBAT1 VPRGM = Logic High VPRGM = Logic Low 4.20 4.10 Adjust Mode Feedback Voltage VADJMF VPRGM = External Divider VCC = 4.2V - 6.5V 3.0 Adjust Mode VVPRGM = 0.1V 1 Adj Mode VPRGM Shunt Resistance RVPGMSH REFGND Output Accuracy Vout = Voutnom + Drefgnd VREFGND Refgnd - Agnd = 30mV REFGND Current IREFGND Refgnd = 0V SC802 Pre-Charge Current IPREQ SC802 Rterm = 3.01kΩ SC802 Termination Current ITERMQ SC802 Rterm = 3.01kΩ TA (-40 oC to +85 oC) Max 4.16 4.06 l ia e d t n 30 35 Max 2 µA 4.24 4.14 V V 0.5 5 kΩ 22 38 mV µA 74 90 mA 42 35.5 49.5 mA IPRGM = 3.01kΩ VBATTERY = 3.8V 500 450 550 mA IPRGM = 3.01kΩ V(AFC) = 0.75V 240 200 280 mA IPREQA SC802A Rterm = 976Ω 145 135 160 mA ITERMQA SC802A Rterm = 976Ω 145 135 160 mA IFastQA IPRGM = 1.78kΩ VBATTERY = 3.8V Rterm = 976Ω 800 740 860 mA SC802A AFC DAC FastCharge Current IDACADJA IPRGM = 1.78kΩ VAFC = 0.75V VBATTERY = 3.8V Rterm = 976Ω 367 310 430 mA IPROG Regulated Voltage VIPRGM 1.5 1.4 1.6 V Adjust Mode Threshold Voltage VTADJM 250 50 420 mV VBAT Precharge Threshold VTPreQ 2.8 2.7 2.9 V VBAT Recharge Threshold VTReQ VBAT - VBATTERY 100 70 140 mV Over Temperature Shutdown TPOT Hysteresis = 10°C 150 SC802 Fast-Charge Current SC802 AFC DAC Fast-Charge Current SC802A Pre-Charge Current SC802A Termination Current SC802A Fast-Charge Current 2005 Semtech Corp. fi n o C IFastQ IDACADJ Vout - BSEN Voltage Confidential Proprietary 3 82 Min Units °C www.semtech.com SC802/SC802A POWER MANAGEMENT Electrical Characteristics (Cont.) Unless otherwise noted: VCC = 4.75V - 5.25V Parameter Symbol Conditions Min EN-NTC Thresholds VTNTCDIS SC802 Disable VTNTCH NTC Hot Vth, VCC = 5V VTNTCC Timer Disable Threshold VTTIMER VRTIME < VTTIMER Disables Timer Internal Timer Select VTINTTS Ext RTIME Voltage Pre-Charge Fault Time-out Complete Charge Time-out fi n o C VCC-VRTIME < VTINTTS selects internal timer 30 31.8 28 32 % 3.62 3.75 3.88 3.6 3.9 V 72.4 75 77.6 72 78 % t n l ia 4.22 4.5 4.58 4.2 4.6 V 84.4 90 91.6 84 92 % 50 1 45 RTIME tied through 36.5kΩ to GND RTIME tied to VCC 3.3 0.5 Leakage Current, V = 5V CPB LED On VCPB Load = 5mA CPB LED Off ICPB Leakage Current, V = 5V BIPB, VPRGM Inputs VIH 0.7 mV 1.1 3 1.4 1.6 -35% +35% hr -35% 0.5 +35% 1 V 1 µA 1 V 1 µA V 0.4 Confidential Proprietary 4 V min 1.8 VIL V V 1.5 50 ICHRGB 2005 Semtech Corp. 28.2 RTIME tied through 36.5kΩ to GND RTIME tied to VCC CHRGB Charge LED Off V V TPreQF Load = 5mA 1.1 1.6 1.5 VCHRGB 0.5 1.4 RTIME tied through 36.5kΩ to GND CHRGB Charge LED On Max 1.59 VRTIME TQCOMP Min 1.5 e d Hot/Cold Vth hysteresis Max 1.41 NTC Enable, VCC = 5V VTNTHYS Typ <1 NTC Cold Vth, VCC = 5V VTNTCEN Units TA (-40oC to +85oC) 25oC V www.semtech.com SC802/SC802A POWER MANAGEMENT PRELIMINARY Pin Configuration Ordering Information Top View DEVICE(1) PACKAGE SC802IMLTR MLP-16 SC802IMLTRT(2) MLP-16 SC802AIMLTRT(2) MLP-16 SC802EVB(3) Evaluation Board Note: (1) Only available in tape and reel packaging. A reel contains 3,000 devices. (2) TRT extension designates the lead-free leadframe package option. This product is fully WEEE and RoHS compliant. (3) Specify the desired IC part number when ordering. (MLP-16 Lead: 4x4) Pin Descriptions Pin # Pin Name Pin Function Battery voltage sense pin. Connect to battery terminal to Kelvin sense battery voltage. Do not leave this pin floating. 1 BSEN 2 VPRGM Selectable voltage program pin. Logic low = 4.1V. Logic high = 4.2V. Resistor = adjustable. 3 IPRGM Charger current program pin in fast charge mode. Requires a resistor to ground to program fastcharge current. 4 ITERM Selection for current termination and pre-charge current. Requires a resistor to ground to program pre-charge and termination current. 5 REFGND 6 GND 7 EN-NTC Reference Ground. Allows Kelvin connection to battery negative terminal. Ground Combined Device enable/disable and NTC input pin. Logic high enables device. Logic low disables device. Analog voltages between 0.3VCC and 0.75VCC enable the NTC function. BIPB Battery in Place Bar (BIPB) selects Charge/LDO mode. BIPB=Low selects charge mode. BIPB=High selects LDO mode which disables Pre-Charge and timer-out functions 9 A FC Analog Fast Charge Setting. Connect to DAC for analog control of fast charge current value. Connect to VCC to disable AFC. Do not leave open. 10 CHRGB 11 C PB 8 © 2005 Semtech Corp. Open Drain Charger Status Pin. The output is active low when the Charger is on and the output current exceeds the termination current value. The output switches to high impedance when Iout < Itermination. This pin can sink 10mA. Open Drain Charger present indicator. The output is active low when the VCC exceeds UVLO. This pin can sink 10mA. 5 www.semtech.com SC802/SC802A POWER MANAGEMENT PrelimiPin Descriptions (Cont.) nary Pin # Pin Name Pin Function Programable timer input pin. Connect to VCC to select the internal time-out of 3hrs, connect to ground to disable the timer. Connect an external resistor to ground to program the timeout period. 12 RTIME 13 VC C Supply pin, connect to adaptor power. 14 VC C Supply pin, connect to adaptor power. 15 VOUT Charger output, connect to battery. 16 VOUT Charger output, connect to battery. T Thermal P ad Pad for heatsinking purposes. Connect to ground plane using multiple vias. Not connected internally. Block Diagram VCC 13 BSEN 1 AFC 9 4.2V Reference Voltages 14 Pre-Charge Ref 4.1V Fast Charge Ref Pre-Charge Ref REFGND 5 Vout VPRGM Vprog Mode Detect 2 15 Control VOUT Pre-Charge On 16 Fast-Charge On Charge/LDO On Over Temp Under Voltage GND 6 BIPB 8 Over Voltage IPRGM EN-NT C 7 NT C Interface 3 Programmable Timer 4 Fast Charge Ref RTIM 12 CPB 11 CHRGB ITERM 10 GND © 2005 Semtech Corp. 6 www.semtech.com SC802/SC802A POWER MANAGEMENT PRELIMINARY Applications Information ceeds 1/4 of the total charge cycle the charger will turn off due to a pre-charge fault. This fault is cleared when EN or VCC is toggled or the output voltage rises above 2.8V. General Operation The SC802 is configured based on the application for Fast Charge and Termination current, output voltage, timing requirements, and operation with and without a battery (ldo mode). A typical charging cycle is described below. Details on alternate applications and output programmability are covered in the individual sections. Fast-Charge Mode (CC) The fast-charge or CC mode is active when the battery voltage is above 2.8V and less than the CV or final float charge voltage of the battery. The fast-charge current can be set to a maximum of 1.0A and is selected by the program resistor on the IPRGM pin. The voltage on this pin will represent the current through the battery enabling a microprocessor via an analog-to-digital converter (ADC) to monitor battery current by sensing the voltage on the IPRGM pin. The equation to set the fast-charge current is given by: The charging cycle begins when the adapter is plugged in. The SC802 performs glitch filtering on the VCC input and initiates a charge cycle when VCC > UVLO. At this time, the CPB and CHRGB signals are active turning on the charger LED’s. If the battery voltage is less than 2.8V, the SC802 will charge the output with the precharge current. When the battery voltage exceeds 2.8V, the SC802 enters fast-charge or constant current (CC) mode. When the battery voltage reaches its final value, the charger enters the constant voltage (CV) mode. In this mode the output current decreases as the battery continues to charge until the termination current level is reached. ⎛ 1.5 ⎞ ⎟⎟ × 1000 SC802 : FCI = ⎜⎜ ⎝ R PRGM ⎠ ⎛ 1.5 ⎞ ⎟⎟ × 1000 - 0.3 × Iterm SC802A : FCI = ⎜⎜ ⎝ R PRGM ⎠ Note that for a given program resistor the current through the battery in CV mode can be determined by replacing 1.5 with the actual voltage on the IPRGM pin in the above equation. The CC current can also be modified by applying an analog voltage to the AFC pin as described below. The CHRGB led turns off when Iout is less than Itermination but the SC802 continues to hold the battery in CV charge mode until the timer expires. At this point the charger enters the monitor mode where the output remains off until Vout drops by 100mV and a new charge cycle is initiated. Analog Fast Charge (AFC Pin) Many applications require more than one current setting for Fast Charge. This feature is included in the SC802 by using the AFC function. When the AFC pin is connected to VCC the device behaves as described in the previous section. When the AFC pin is driven by and analog voltage between 0 and 1.5V the SC802 automatically uses this pin voltage to set the maximum fastcharge current setting according to the following equation. Pre-Charge Mode Pre-charge mode is automatically enabled whenever the battery voltage is below 2.8V. It is used to limit the power dissipation and precondition the battery for fast charging. The pre-charge current value is selected by the resistor on the ITERM pin. The pre-charge current is programmable from 10mA to 125mA on the SC802 and up to 150mA on the SC802A. The equation to select the pre-charge current is different for the two part types and given by: ⎛ V ⎞ SC802 : AFCI = ⎜⎜ AFC ⎟⎟ × 1000 ⎝ R PROG ⎠ ⎛ 2.8 ⎞ ⎟⎟ × 88 SC802 : PCI = ⎜⎜ R ⎝ TERM ⎠ ⎛ 1.5 ⎞ ⎟⎟ × 97 SC802A : PCI = ⎜⎜ ⎝ R TERM ⎠ ⎛ V ⎞ SC802A : AFCI = ⎜⎜ AFC ⎟⎟ × 1000 - 0.3 × Iterm ⎝ R PROG ⎠ If the charge timer is in use there is also a maximum allowed pre-charge duration. If the pre-charge time ex© 2005 Semtech Corp. 7 www.semtech.com SC802/SC802A POWER MANAGEMENT Applications PrelimiInformation Cont. nary Termination Current Charge Timer The timer on the SC802 is used as protection in the case of a faulty battery and to maximize charging capacity. Tie the RTIM pin to VCC to select the internal timer, GND to disable the timer. Connecting a resistor between RTIM and GND will program the total charge time according to the following equation with the charge time expressed in hours. Once the battery reaches the program voltage of 4.1V, 4.2V or externally set voltage, the device will transition from a constant current source to a constant voltage source. The current through the battery begins to decrease while the voltage remains constan until it falls below the programmed termination current set by the termination resistor on the ITERM pin. The SC802 will turn off the CHRGB Led. If the timer is enabled the output will continue to float charge in CV mode until the timer expires. If the timer is disabled than the output will turn off as soon as the termination current level is reached. The equation for setting the the termination current RTIM = Total Q Time × 12.5kΩ The timer is programmable over the range of 2 to 6hrs. The internal timer selection results in a charge time of 3hrs. The CHRGB blink rate in fault condtions is a function of the timer setting when an external RTIM is used. The SC802 will automatically turn off the output when the charge timer times out. ⎛ 1.5 ⎞ ⎟⎟ × 88 SC802 : ITERM = ⎜⎜ ⎝ R TERM ⎠ LDO Mode The SC802 is designed to work with or without a battery. If the battery is not in place the device can enter the LDO mode. In this mode the SC802 will act like a low dropout regulator. The output voltage is set to 4.1V, 4.2V or externally set by a resistor divider. See the section titled “Configuring the output voltage to the battery” for setting an output voltage. The input pin BIPB (Battery In Place Bar) is used to switch the SC802 from charger mode to LDO mode. If this pin is logic high the device will be in LDO mode, if it is logic low it will be in the charger mode. During LDO mode the device will regulate the output voltage with a current limit set by the resistor tied to the IPRGM pin. The BIPB pin should never be left floating. It should be tied through pull-up/pull-down resistors when connected to a high impedance control pin or it can be connected directly to the VCC pin or GND. ⎛ 1.5 ⎞ ⎟⎟ × 97 SC802A : ITERM = ⎜⎜ R ⎝ TERM ⎠ The termination current is programmable up to 67mA for the SC802. The termination current is programmable up to 150mA with VCC=5V on the SC802A. Monitor Mode When a charge cycle is completed, the SC802 output turns off and the device enters monitor mode. If the voltage of the battery falls below the recharge threshold of CV-100mV the charger will clear the charge timer and re-initiate a charge cycle. The maximum current drain of the battery during monitor mode will be no more than 1uA over temperature. The status of the charger output as a function of BIPB, Timer, and IOUT is shown below. Output State BIPB Timer Io ut On High N /A N /A On Low T < Timer N /A Off Low T > Timer N /A Off Low Disabled < Itermination © 2005 Semtech Corp. EN-NTC Interface The Enable pin on the SC802 provides two functions. It can be used to turn on/off the device by driving it to VCC/Ground. It can also be connected to an external resistor divider consisting of a resistor and an NTC Thermistor to disable the charge cycle when the temperature is out of range. This configuration is shown in the typical application schematic on page 1 of the datasheet. When the NTC voltage from the divider is above or below the hot and cold temperature threshold values the SC802 will suspend the charge cycle by turning off the output, freezing the charge timer, and indicating a fault on the CHRGB LED. Hysteresis is included for both thresholds to avoid chatter at the NTC trip points. When the tem8 www.semtech.com SC802/SC802A POWER MANAGEMENT PRELIMINARY Applications Information Cont. than 0oC and 50oC alternate curve-type NTC elements can be used or an additional resistor can be added to the Rntc divider to alter the temperture coefficient. perature returns to the valid range the SC802 automatically resumes the charge cycle. The charge timer will time-out when the SC802 output on-time exceeds the timer setting regardles of how long it has been disabled due to temperature. The internal NTC thresholds of 30% and 75% VCC were designed to work with curve-2 type thermistors available from numerous vendors. LED Flags There are two LED drivers on the SC802: CHRGB (Charge) and CPB (Charger Present). These outputs are open drain NMOS drivers for controlling LEDs directly. The Table below defines each LED output state. Design Example based on the typical application schematic of page 1 using a Curve 2 Vishay-Dale NTC. Thot = 50oC Tcold = 0oC Find R3 and RT1 Step 1: Pick an RT1 value high enough to prevent selfheating. 2 ( V(RT1) ) RT1 ≥ LED FLAG ON OFF Blinking CPB U V LO < VCC < OVP Power N ot Good X CHR GB Iout > Iterm Iout < Iterm* PreCharge or N TC Fault * Output remains on when timer is enabled and t < timeout DC In general lower values of RT1 provide more noise for the NTC voltage at the expense of bias current from the input adapter. The dissipation constant DC is the power rating of the NTC resulting in a 1oC self heating error. The CPB output can be used for a VCC indicator. Regardless of the state of EN, the CPB output reflects the voltage of the VCC (adapter) input. When VCC is between the UVLO and OVP thresholds the CPB output is low. The DC value for this NTC is 3mW and the voltage across the NTC is 2.5V for a 5V adapter. Therefore RT1 > 2k. The CHRGB output signifies the charging status. When the output current is > Itermination, CHRGB=low. CHRGB is high when Iout is < Itermination. The CHRGB output is latched during the charge cycle when the output current is less than Itermination. This latch is reset when the battery enters a re-charge cycle, or if BIPB, EN, or VCC are toggled. The CHRGB indicator operates the same way in both charge and ldo mode. Set RT1 = 10k Step 2: Find R3 to set the correct Hot level trip point ⎛ ⎛ R T50 ⎞ ⎞ ⎟ ⎟ = 9.52k R3 = 2.33 × ⎜ R T25 × ⎜⎜ ⎟⎟ ⎜ R ⎝ T25 ⎠ ⎠ ⎝ There are five fault modes detected by the SC802; (Input under voltage, input over voltage, NTC temperature, Max die temperature or OT and pre-charge timeout) The LED states for these fault modes are shown below. The closest standard resistor value is 9.53k. RT(temp)/ RT(25oC) is often referred to as the ratio at the given temp. For this NTC at 50oC the ratio is 0.4086. Step 3: Calculate the Tcold value. ⎛ RTCOLD ⎞ ⎛ R3 ⎞ ⎜⎜ ⎟⎟ = 3 × ⎜ ⎟ = 2.86 ⎝ 10k ⎠ ⎝ RT25 ⎠ The ratio for the Curve 2 NTC at 0o is 2.816. The difference represents less than 1/2oC (ie actual trip would be -0.5oC instead of 0oC.) For temperature trip values other © 2005 Semtech Corp. 9 Fault CPB CHR GB VCC UVLO or VCC OVP off off NTC Fault on Blinking Pr e -Char ge Time -o ut on Blinking Tj > 150C off off www.semtech.com SC802/SC802A POWER MANAGEMENT Preliminary 14 13 3 7 4 8 6 5 CHARGER VIN R5 C1 1uF RT1 THERMISTOR SC802 11 10 12 2 1 16 15 9 VCC CPB VCC CHRGB IPRGM RTIM EN/NTC VPRGM ITERM BSEN BIPB VOUT VOUT GND RFGND AFC R3 R4 R2 R6 CHARGE CHARGER PRESENT ADC Iset R1 BATTERY t C2 2.2uF C1 R7 1K R8 1K Adjust Mode Schematic Capacitor Selection Input and output capacitors can be low cost ceramic type. The output capacitance range is 1uF to 4.7uF. The input capacitor is typically between 0.1uF to 1uF but larger values will not degrade performance. Configuring the Output Voltage to the Battery Fixed Mode The battery voltage is set by the VPRGM pin in fixed mode and externally in adjust mode. If VPRGM is logic high the output voltage is set to 4.2V. If this pin is logic low the output voltage will be set to 4.1V. For a value other than 4.1V or 4.2V a resistor divider is required. Overcurrent and Max Temperature Protection Overcurrent protection is inherent in all modes of operation. When the device is in charge-mode (BIPB=low) the output is current limited to either the pre-charge current limit value or the fast charge current limit value depending on the voltage at the output. When the device is in LDO mode (BIPB=high) the output current is limited to the fast charge current limit. Max die temperature protection is included on the SC802. This feature allows the SC802 to operate with maximum power dissipation by disabling the output current when the die temperature reaches OT. The result is that the SC802 will operate as a pulse charger in extreme power dissipation applications delivering the maximum allowable output current while regulating the internal die temperature to a safe level. Adjust Mode When the SC802 is configured with an output voltage other than 4.1 or 4.2V it is operating in adjust mode. In adjust mode the output voltage is set by an external resistor divider. The SC802 provides the ability to disconnect the external feedback resistor divider when the battery is not being charged to reduce current drain from the battery in normal operation. Connect the external resistor divider between the VOUT pin and the VPRGM pin with the divider tap connected to the BSEN pin to utilize this feature. The SC802 adjust mode schematic is shown above. The equation for setting the output voltage is: ⎛ R4 ⎞ VOUT = ⎜1 + ⎟ × 3.0 ⎝ R3 ⎠ Remote Kelvin Sensing at the Battery Kelvin sensing of both the positive and negative terminals of the battery is possible with the SC802. The BSEN pin provides the positive sensing voltage feedback to the CV amplifier and should be connected as close to the battery + terminal as possible. Likewise the REFGND pin should be kelvin connected to the negative terminal of the battery. This allows the designer great flexibility in PCB layout and achieves a much greater accuracy in sensing the battery voltage where it counts, at the battery terminals! Therefore, when laying out the PCB the designer should route the BSEN pin directly to the terminal at which the battery gets connected. In the LDO mode, the BSEN pin will still need to sense the output voltage; therefore BSEN should never be left floating.. The capacitor across R4 in the feedback networks introduces zero-pole frequency compensation for stability. Place the zero according to the following equation to insure stability. R4 × C1 = 1 2π × 100kHz When the SC802 is in Adjust mode the VCC is required to be 150mV > Vout. Internal protection circuits will disable the output if VOUT approaches VCC. © 2005 Semtech Corp. 10 www.semtech.com SC802/SC802A POWER MANAGEMENT PRELIMINARY State Diagram Over Voltage, Under Voltage, or Over Temperature will force the SC802 into Shutdown Mode from any state. OVP> Vin > UVLO En=Hi Shutdown Mode Vout/Iout off CHRGB High Z CPB Low Yes Soft Start Vout CC=Constant Current CV=Constant Voltage CHRGB Low Start LDO Mode BIPB=Low Yes Timer Enabled? Yes Start Timer Soft Start CC Mode Iout<Iterm Yes Iout=1500/Rprog CHRGB High Z Start Pre-Charge Yes Float Charge Mode Vout = CV Yes Vout=CV Yes Start CV Mode Vout< CV-100mV Yes Time>Tmax Vout>2.8V SC802:Iout=246/Rterm SC802A:Iout=145/Rterm Time>Tmax/4 Yes Iout<Iterm Yes Monitor Mode Vout=off Yes CHRGB High Z Vout< CV-100mV Timer Enabled? Pre-Charge Timeout Fault CHRGB blinks at 0.5Hz Cleared by Vbat>2.8V or Re-cycle EN or VCC 0C > NTC Temp >50C Yes Yes Time>Tmax Float Charge Mode Vout = CV © 2005 Semtech Corp. 11 NTC out of Range Fault CHRGB blinks at 0.5Hz Timer is frozen Charge resumes when NTC Temperature is valid www.semtech.com SC802/SC802A R3 3K R4 3.01K VCC CPB CHRGB VCC RTIM IPRGM EN-NTC VPRGM ITERM BSEN BIPB VOUT GND VOUT RFGND AFC SC802 11 10 12 2 1 16 15 9 1 1 1 R2 100K R7 37.5K TP5 GND JP1 4.2V 1 JP2 TINT TP4 VOUT 2 1 U1 14 13 3 7 4 8 6 5 R5 JP4 4.1V 0 C2 C3 No Pop 2.2uF 2 1 TP8 RGND R6 1M D2 CP 1 D3 No Pop 1 JP3 LDO R1 10K TP6 AFC 2 1 TP7 ISENSE 2 C1 1uF D1 CHRG 1 TP3 EN-NTC 1 TP1 TP2 CHARGER+ CHARGER1 POWER MANAGEMENT PrelimiEvaluation Board Schematic nary R9 0 R8 No Pop Marking Information 802 yyww 802A yyww Top view. Marking for the SC802 MLP 16 Lead package: yyww = Date Code (Example: 0012) © 2005 Semtech Corp. 12 www.semtech.com SC802/SC802A POWER MANAGEMENT PRELIMINARY Typical Characteristics SC802 (non-A) Output Current -vs- Rterm 2 250 1.5 200 Current (A) Current (A) Output Current -vs- Rprgm 1 0.5 150 100 50 0 7 6.5 5.5 5 4.5 4 3.5 3 2.5 2 1.5 1 0.75 0 0.8 1.5 2.5 3.5 4.5 Resistance (Kohm ) 6 8.5 10 11.8 14 Resistance (Kohm ) Fast Charge SC802 Pre-Charge Drop-out Voltage -vs- Output Current SC802 Termination Time-Out -vs Rtim e 8 1000 800 600 500 450 300 250 200 100 54 Time-out (hrs) Dropout Voltage (mV) 700 600 500 400 300 200 100 0 6 4 2 0 10 Output Current (m A) 20 40 60 80 Resistance (Kohm ) Pre-Charge Timeout Fast Charge Timeout V dropout 0.5 0.4 0.3 0.2 0.1 CURRENT (Amps) 0.6 4.4 4.2 4 3.8 3.6 3.4 3.2 3 3:45:00 3:20:00 3:32:30 2:42:30 2:55:00 3:07:30 2:17:30 2:30:00 1:40:00 1:52:30 2:05:00 1:15:00 1:27:30 0:37:30 0:50:00 1:02:30 0:12:30 0:25:00 0 0:00:00 VOLTAGE (Volts) Battery Charge Profile TIME V CHARGE © 2005 Semtech Corp. V CHRGB 13 I CHARGE www.semtech.com SC802/SC802A POWER MANAGEMENT Charge ModePrelimiTiming Diagram nary Charge Mode Timing UVLO VCC 2.8V VOUT IOUT Fast Charge Soft Start Termination Current Re-Charge Threshold Pre-Charge CC-mode CV-mode CPB On CHRGB On TIMER On Off Off On Hold On Fault NTC LDO Mode Timing Diagram LDO-Mode Timing UVLO VCC 2.8V VOUT Fast Charge Termination Current IOUT Re-Charge Threshold Soft Start CC-mode CV-mode Load Current Transient CPB CHRGB TIMER (Disabled) On Off Off Fault NTC © 2005 Semtech Corp. On 14 www.semtech.com SC802/SC802A POWER MANAGEMENT PRELIMINARY Outline Drawing - MLP-16 (4 x 4 x 0.9mm) A DIMENSIONS INCHES MILLIMETERS DIM MIN NOM MAX MIN NOM MAX D A A1 A2 b D D1 E E1 e L N aaa bbb B PIN 1 INDICATOR (LASER MARK) E A2 A aaa C A1 C .031 .040 .000 .002 (.008) .010 .012 .014 .153 .157 .161 .079 .085 .089 .153 .157 .161 .079 .085 .089 .026 BSC .018 .022 .026 16 .003 .004 0.80 1.00 0.00 0.05 (0.20) 0.25 0.30 0.35 3.90 4.00 4.10 2.00 2.15 2.25 3.90 4.00 4.10 2.00 2.15 2.25 0.65 BSC 0.45 0.55 0.65 16 0.08 0.10 SEATING PLANE D1 e/2 LxN E/2 E1 2 1 N e D/2 bxN bbb C A B NOTES: 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). 2. COPLANARITY APPLIES TO THE EXPOSED PAD AS WELL AS THE TERMINALS. © 2005 Semtech Corp. 15 www.semtech.com SC802/SC802A POWER MANAGEMENT Land PatternPrelimi- MLP-16 (4 x 4 x 0.9mm) nary K DIM 2x (C) H 2x G 2x Z Y X C G H K P X Y Z DIMENSIONS INCHES MILLIMETERS (.152) .114 .091 .091 .026 .016 .037 .189 (3.85) 2.90 2.30 2.30 0.65 0.40 0.95 4.80 P NOTES: 1. THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY. CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR COMPANY'S MANUFACTURING GUIDELINES ARE MET. Contact Information Semtech Corporation Power Management Products Division 200 Flynn Road, Camarillo, CA 93012 Phone: (805)498-2111 FAX (805)498-3804 © 2005 Semtech Corp. 16 www.semtech.com