SD8017

SD8017 SHOUDING | Alldatasheet

Document overview

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Technical content

Features

¾ Programmable Charge Current Up to 800mA. ¾ No MOSFET, Sense Resistor or Blocking Diode Required. ¾ Constant-Current/Constant-Voltage Operation with Thermal Protection to Maximize Charge Rate without Risk of Overheating. ¾ Charges Single Cell Li-Ion Batteries Directly from USB Port. ¾ Preset 4.2V Charge Voltage with ±1% Accuracy. ¾ 20uA Supply Current in Shutdown. ¾ 2.9V Trickle Charge Threshold ¾ Soft-Start Limits Inrush Current. ¾ Available in 5-Lead SOT-23 and PSOP-8 (Exposed Pad) Packages. ¾ RoHS Compliant and 100% Lead (Pb)-Free Pin Configuration Application ¾ Cellular Telephones, PDA’s, MP3 Players. ¾ Charging Docks and Cradles ¾ Bluetooth Applications Application Diagram SD8017 SD8017 www.shouding.net Shouding

(1) Parameter Symbol Value Units Input Supply Voltage V CC 7 V PROG Voltage V PROG VCC+0.3 V BAT Voltage V BAT 7 V CHRG Voltage V CHRG 7 V BAT Short-Circuit Duration Continuous 250 (SOT-23-6) Thermal Resistance, Junction-to-Ambient Θ JA 75(PSOP8) °C/W BAT Pin Current I BAT 800 mA PROG Pin Current I PROG 800 μA Maximum Junction Temperature T J 125 °C Storage Temperature T S -65 to +125 °C Lead Temperature (Soldering, 10 sec) 300 °C Operating Rating (2) Parameter Symbol Value Units Supply Input Voltage V IN -0.3 to +7 V Junction Temperature T J -40 to +85 °C

Electrical Characteristics

V IN = 5V; T J = 25°C; unless otherwise specified. Symbol Parameter Conditions Min Typ Max Unit V CC Input Supply Voltage 4.25 6 V Charge Mode (3) , R PROG = 10k 110 500 µA Standby Mode (Charge Terminated) 70 µA I CC Input Supply Current Shutdown Mode(R PROG Not Connected, V CC < V BAT , or V CC < V UV 20 40 µA V FLOAT Regulated Output (Float) Voltage I BAT = 30mA, I CHRG = 5mA 4.158 4.2 4.242 V R PROG = 10k, Current Mode 90 106 130 mA R PROG = 2k, Current Mode 530 mA Standby Mode, VBAT = 4.2V 0 +/-1 +/-5 µA Shutdown Mode (R PROG Not Connected) +/-0.5 +/-5 µA I BAT BAT Pin Current Sleep Mode, V CC = 0V +/-1 +/-5 µA I TRIKL Trickle Charge Current V BAT < V TRIKL , R PROG = 10k 10 mA V TRIKL Trickle Charge Threshold Voltage R PROG = 10k, V BAT Rising 2.8 2.9 3.0 V www.shouding.net SD8017 Shouding

Note 1: Exceeding the absolute maximum rating may damage the device. Note 2: The device is not guaranteed to function outside its operating rating. Note 3: Supply current includes PROG pin current (approximately 100µA) but does not include any current delivered to the battery through the BAT pin (approximately 100mA). Note 4: I TERM is expressed as a fraction of measured full charge current with indicated PROG resistor. Electrical Characteristics (Continued) V IN = 5V; T J = 25°C; unless otherwise specified Symbol Parameter Conditions Min Typ Max Unit V UV V CC Undervoltage Lockout Threshold From V CC Low to High 3.4 V V UVHYS V CC Undervoltage Lockout Hysteresis 100 mV PROG Pin Rising 1.25 V V MSD Manual Shutdown Threshold Voltage PROG Pin Falling 1.2 V V CC from Low to High 100 mV V ASD V CC – V BAT Lockout Threshold Voltage V CC from High to Low 30 mV R PROG = 10k (4) 0.1 mA/mA I TERM C/10 Termination Current Threshold R PROG = 2k 0.1 mA/mA V PROG PROG Pin Voltage R PROG = 10k, Current Mode 0.9 1.03 1.1 V I CHRG CHRG Pin Weak Pull-Down Current V CHRG = 3V 15 µA V CHRG CHRG Pin Output Low Voltage I CHRG = 5mA 0.6 V ΔV RECHRG Recharge Battery Threshold Voltage V FLOAT - V RECHRG 100 mV T LIM Thermal Protection Temperature 120 °C t SS Soft-Start Time I BAT = 0 to 1000V/R PROG 100 µs t RECHARGE Recharge Comparator Filter Time V BAT High to Low 1 ms t TERM Termination Comparator Filter Time I BAT Falling Below I CHG /10 1000 µs I PROG PROG Pin Pull-Up Current 1 µA Pin Functions Pin Pin Function Description Pin Pin Function Description VCC P Positive Input Supply Voltage. Provides power to the charger. VCC can range from 4.25V to 6.5V and should be bypassed with at least a 1μF capacitor. CHRG Open-Drain Charge Status Output. When the battery is charging, the CHRG pin is pulled low by an internal N-channel MOSFET. When the charge cycle is completed, a weak pull-down of approximately 20uA is connected to the CHRG pin, indicating an “AC present” condition. GND Ground. PROG Charge Current Program, Charge Current Monitor and Shutdown Pin. BAT Charge Current Output. Provides charge current to the battery and regulates the final float voltage to 4.2V. CHRGT Open-Drain Charge Termination Status Output. When the battery is charging, the CHRGT pin is pulled high by an external compenent such as an LED. After the charging is completed, this pin is pulled low by internal N-channel MOSFET and it can be used as a charging termination indicator. www.shouding.net SD8017 Shouding

www.shouding.net SD8017 Shouding

Float Voltage vs Supply Voltage 4.185 4.190 4.195 4.200 4.205 4.210 4.215 4.220 4.225 4.230 V CC (V) V BAT (V) R PROG =10k T A =25℃ Charge Current vs Supply Voltage 100 200 300 400 500 600 V CC (V) I BAT (mA) R PROG =2k R PROG =10k V BAT =4V T A =25℃ ONSET OF THERMAL REGULATION Trickle Charge Current vs Supply Voltage V CC (V) I TRIKL (mA) R PROG =2k V BAT =2.5V T A =25℃ R PROG =10k Float Voltage vs Temperature 4.185 4.190 4.195 4.200 4.205 4.210 4.215 20 40 60 80 100 120 Temperature (℃) V FLOAT (V) www.shouding.net SD8017 Shouding

The SD8017 constantly monitors the BAT pin voltage programmed value, the SD8017 terminates the the SD8017 enters standby float voltage (4.2V), the SD8017 enters the SD8017 supplies approximately 1/10 the components. Furthermore, the SD8017 is capable final float voltage accuracy of ±1%. The SD8017 The SD8017 is a single cell lithium-ion battery Revision 10/9/2008 current are calculated using the following equations: 1060 1060, PROG CHG CHG PROG VVRI IR== The charge current out of the BAT pin can be determined at any time by monitoring the PROG pin voltage using the following equation: 1060 PROG BAT PROG VI R=• This actual current will vary from IC to IC. The typical variation is within +/-20%. O pera ti on charger using a constant-current/constant-voltage algorithm. It can deliver up to 800mA of charge current (using a good thermal PCB layout) with a 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 of operating from a USB power source. Normal Charge Cycle A charge cycle begins when the voltage at the VCC pin rises above the UVLO threshold level and a 1% program resistor is connected from the PROG pin to ground or when a battery is connected to the charger output. If the BAT pin is less than 2.8V, the charger enters trickle charge mode. In this mode, programmed charge current to bring the battery voltage up to a safe level for full current charging. When the BAT pin voltage rises above 2.8V, the charger enters constant-current mode, where the programmed charge current is supplied to the battery. When the BAT pin approaches the final constant-voltage mode and the charge current begins to decrease. When the charge current drops to 1/10 of the programmed value, the charge cycle ends. Programming Charge Current The charge current is programmed using a single resistor from the PROG pin to ground. The battery charge current is 1060 times the current out of the PROG pin. The program resistor and the charge Charge Termination A charge cycle is terminated when the charge current falls to 1/10th the programmed value after the final float voltage is reached. This condition is detected by using an internal, filtered comparator to monitor the PROG pin. When the PROG pin voltage falls below 100mV for longer than t TERM (typically 1ms), charging is terminated. The charge current is latched off and mode, where the input supply current drops to 200mA. (Note: C/10 termination is disabled in trickle charging and thermal limiting modes). When charging, transient loads on the BAT pin can cause the PROG pin to fall below 100mV for short periods of time before the DC charge current has dropped to 1/10th the programmed value. The 1ms filter time (t TERM ) 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 1/10th the charge cycle and ceases to provide any current through the BAT pin. In this state, all loads on the BAT pin must be supplied by the battery. www.shouding.net SD8017 Shouding

conditions and the SD8017 is ready to charge. High indicates that the SD8017 is in a charge cycle. Once Revision 10/9/2008 Undervoltage Lockout (UVLO) An internal undervoltage lockout circuit monitors the input voltage and keeps the charger in shutdown mode until VCC rises above the undervoltage lockout threshold. The UVLO circuit has a built-in hysteresis of 200mV. Furthermore, to protect against reverse current in the power MOSFET, the UVLO circuit keeps the charger in shutdown mode if VCC falls to within 30mV of the battery voltage. If the UVLO comparator is tripped, the charger will not come out of shutdown mode until VCC rises 100mV above the battery voltage. Trickle Charge Mode TH of Full Current Chrg LED: Strong Pull-Dn CC/CV Charge Mode Full Current Chrg LED: Strong Pull-Dn Standby Mode No Charge Current Chrg LED: Weak Pull-Dn Shutdown Mode I CC Drops to < 20μA Chrg: Hi-Z In UVLO WeakPull-Dn Otherwise V BAT <2.8V V BAT >2.8V V BAT >2.8V V PROG <100mV 4.05V>V BAT >2.8V Power On PROG Reconnected Or UVLO Connection Stops PROG Floated Or UVLO Connection Figure1. State Diagram of a Typical Charge Cycle in standby mode. If this voltage drops below the4.05V recharge threshold (V RECHRG ), another charge cycle begins and 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 PROG pin. Figure 1 shows the state diagram of a typical charge cycle. Charge Status Indicator (CHRG) The charge status output has three different states: strong pull-down (~10mA), weak pull-down (~20 μA) and high impedance. The strong pull-down state the charge cycle has terminated, the pin state is determined by undervoltage lockout conditions. A weak pull-down indicates that V CC meets the UVLO undervoltage lockout mode: either V CC is less than 100mV above the BAT pin voltage or insufficient voltage is applied to the V CC pin. 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 120 ℃. This feature protects the 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 . The charge current can be set according to typical (not worst-case) ambient temperature with the assura nce that the charger will automatically reduce the current in worst-case conditions. www.shouding.net impedance indicates that the SD8017 is in SD8017 Shouding

The conditions that cause the SD8017 to reduce Revision 10/9/2008 Power Dissipation charge current through thermal feedback can be approximated by considering the power dissipated in the IC. Nearly all of this power dissipation is generated by the internal MOSFET—this is calculated to be approximately: P D = (V CC – V BAT ) • I BAT The approximate ambient temperature at which the thermal feedback begins to protect the IC is: T A = 120°C – P D θ JA T A = 120°C – (V CC – V BAT ) • I BAT

• θ JA A pp li ca ti on Hi n t s 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 is recommended to reduce ripple voltage. When using high value, low ESR ceramic capacitors, it is recom mended to add a 1Ω resistor in series with the capacitor. No series resistor is needed if tantalum capacitors are used. In constant-current mode, the PROG pin is in the feedback loop, not the battery. The constant-current mode stability is affected by the impedance at the PROG pin. With no additional capacitance on the PROG pin, the charger is stable with program resistor values as high as 20k. However, additional capacitance on this node reduces the maximum allowed program resistor. The pole frequency at the PROG pin should be kept above 100kHz. 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 hi gh 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 1.5Ω resistor in series with a ceramic capacitor will minimize start-up voltage transients. Thermal Considerations Because of the small size of the thin SOT23 package, it is very importa nt to use a good thermal PC board layout to maximize the available charge current. The thermal path for the heat generated by the IC is from the die to the copper lead frame, through the package leads, (especially the ground lead) to the PC board copper. The PC board copper is the heat sink. The footprint copper pads should be as wide as possible and expand out to larger copper areas to spread and dissipate the heat to the surrounding ambient. Other heat sources on the board, not related to the charger, must also be considered when designing a PC board layout because they will affect overall temperature rise and the maximum charge current. 8 www.shouding.net SD8017 Shouding

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