RT9516 Linear Single Cell Li-lon Battery Charger with Single Input Supply for Portable Applications General Description Features The RT9516 is a fully integrated low cost single-cell Li-Ion battery charger ideal for portable applications. The RT9516 is capable of being powered up from AC adapter and USB (Universal Serial Bus) port inputs. The RT9516 enters sleep mode when supplies are removed. The RT9516 optimizes the charging task by using a control algorithm including preconditioning mode, fast charge mode and constant voltage mode. The charging task will keep in constant voltage mode to hold the battery in a full charge condition. The charge current can be programmed with an external resister. The internal thermal feedback circuitry regulates the die temperature to optimize the charge rate for all ambient temperatures. The RT9516 features 28V maximum rating voltages for VIN. The other features are under voltage protection, over voltage protection for AC adapter supply. z The RT9516 is available in WDFN-8L 2x2 tiny package to achieve best solution for PCB space and total BOM cost saving considerations. Ordering Information RT9516 Package Type QW : WDFN-8L 2x2 (W-Type) Lead Plating System G : Green (Halogen Free and Pb Free) z z z z z z z Applications z z z z Cellular Phones Digital Cameras PDAs and Smart Phones Probable Instruments Pin Configurations (TOP VIEW) VIN GND ISET ABI 1 2 3 4 GND RT9516 also provide a booting assistant circuit which detect input source and battery connection condition and provide an output signal (ABO) for system booting. z 28V Maximum Rating for AC Adapter Internal Integrated Power MOSFETs AC Adapter Power Good Status Indicator Programmed Charging Current Output for Auto-Booting Under Voltage Protection Over Voltage Protection Thermal Feedback Optimizing Charge Rate RoHS Compliant and Halogen Free 9 8 7 6 5 BATT PGOOD EN ABO WDFN-8L 2x2 Marking Information For marking information, contact our sales representative directly or through a Richtek distributor located in your area. Note : Richtek products are : ` RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020. ` Suitable for use in SnPb or Pb-free soldering processes. DS9516-01 April 2011 www.richtek.com 1 RT9516 Typical Application Circuit VIN (Adapter or USB) 1 CIN 1µF VIN BATT 3 2 RSET COUT 2.2µF RT9516 6 EN 4 ABI Chip Enable 8 PGOOD 7 Battery Pack To System ISET GND System Supply ABO 5 Function Block Diagram BATT VIN PGOOD CC/CV/TR Loop Controller ISET OVP VBATT UVLO Logic Controller ABO 200k EN 200k GND ABI www.richtek.com 2 DS9516-01 April 2011 RT9516 Flow Chart Standby State P-MOSFET = OFF VIN - VBATT > VOS YES NO VIN < OVP & EN = H YES BATT > 2.5V NO Sleep State P-MOSFET = OFF YES Soft-Start NO Pre_Charge ICHG_pre = (1/10) x ICHG_F CV State VBATT = 4.2V ICHG = 0A Power Off State P-MOSFET = OFF Fast-Charge ICHG_F = 570mA RSET = 2.8k YES VBATT ≥ 4.2V NO Any State or VIN > OVP or EN = H Functional Pin Description Pin No. 1 2, 9 (Exposed Pad) Pin Name VIN GND Pin Function Input Power Source. The VIN can withstand up to 28V input. Power Ground. The exposed pad must be soldered to a large PCB and connected to GND for maximum power dissipation. 3 ISET Charge Current Set Point. 4 ABI Auto-Booting External Input. ABI is pulled to GND through an internal 200kΩ resistor. 5 ABO Auto-Booting Logic Output. 6 EN Charge Enable (Active Low). With internal 200kΩ pull low resistor. 7 PGOOD PGOOD pin connect to VIN with 10Ω N-MOSFET as power good condition. 8 BATT Battery Charge Current Output. DS9516-01 April 2011 www.richtek.com 3 RT9516 Absolute Maximum Ratings z z z z z z z z (Note 1) Supply Voltage, VIN ------------------------------------------------------------------------------------------------------Other Pins ------------------------------------------------------------------------------------------------------------------Power Dissipation, PD @ TA = 25°C WDFN-8L 2x2 -------------------------------------------------------------------------------------------------------------Package Thermal Resistance (Note 2) WDFN-8L 2x2, θJA --------------------------------------------------------------------------------------------------------Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------Junction Temperature ----------------------------------------------------------------------------------------------------Storage Temperature Range -------------------------------------------------------------------------------------------ESD Susceptibility (Note 3) HBM (Human Body Mode) ---------------------------------------------------------------------------------------------MM (Machine Mode) ------------------------------------------------------------------------------------------------------ Recommended Operating Conditions z z z −0.3V to 28V −0.3V to 28V 0.606W 165°C/W 260°C 150°C −65°C to 150°C 2kV 200V (Note 4) Supply Voltage,VIN -------------------------------------------------------------------------------------------------------- 4.5V to 6V Junction Temperature Range -------------------------------------------------------------------------------------------- −40°C to 125°C Ambient Temperature Range -------------------------------------------------------------------------------------------- −40°C to 85°C Electrical Characteristics (VIN = 5V, VBATT = 4V, TA = 25°C, unless otherwise specified) Parameter Symbol Offset Voltage (VIN−VBATT) Rising VOS-R Offset Voltage (VIN− VBATT ) Falling VOS-F VIN Standby Current ISTBY Test Conditions VBATT = 4.5V Over Voltage Protection Threshold VOVP Battery Regulation Voltage VREG Regulation BATT Sleep Leakage Current ISLEEP T A = 0 to 85°C VIN Power MOSFET RDS(ON) I BATT = 0.5A Min Typ Max Unit -10 90 50 150 -- mV mV -- 300 500 μA 6.5 7 7.5 V 4.158 4.2 4.242 V -- 1 10 μA -- 0.4 0.8 Ω -- 1.4 -- V ISET Set Voltage (Fast Charge) VISET Charge Current Accuracy ICHG RSET = 2.8k 524 570 616 mA BATT Pre-Charge Threshold VPCHG_BATT BATT Rising 2.3 2.5 2.7 V Pre-Charge Current IPCHG 4 10 15 % EN Threshold Voltage Logic-High VIH 1.5 -- -- V Logic-Low VIL -- -- 0.4 V -- 200 -- kΩ -- 115 -- °C -- 65 -- mV Enable Pull Low Resistor Thermal Regulation VPGOOD 5mA PGOOD Pull Down Voltage Logic-High ABI Threshold VIH 1.5 -- -- V Voltage VIL -- -- 0.4 V -- 200 -- kΩ -- 100 -- mV Logic-Low ABI Pull Low Resistor ABO Pull Down Voltage www.richtek.com 4 5mA DS9516-01 April 2011 RT9516 Note 1. Stresses listed as the above “Absolute Maximum Ratings” may cause permanent damage to the device. These are for stress ratings. Functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may remain possibility to affect device reliability. Note 2. θJA is measured in the natural convection at TA = 25°C on a low effective thermal conductivity single layer test board of JEDEC 51-3 thermal measurement standard. Note 3. Devices are ESD sensitive. Handling precaution is recommended. Note 4. The device is not guaranteed to function outside its operating conditions. DS9516-01 April 2011 www.richtek.com 5 RT9516 Typical Operating Characteristics BATT Pre-Charge Power On BATT Fast-Charge Power On VBATT (2V/Div) VBATT (2V/Div) EN (1V/Div) EN (1V/Div) VISET (100mV/Div) I IN (200mA/Div) VISET (1V/Div) VIN = 5V, ICHG = 50mA I IN (500mA/Div) VIN = 5V, ICHG = 500mA Time (1ms/Div) Time (1ms/Div) Power Off from ACIN Power Off From EN VIN (5V/Div) VBATT (2V/Div) EN (1V/Div) VBATT (2V/Div) VISET (1V/Div) VISET (1V/Div) I IN (500mA/Div) ICHG = 500mA I IN (500mA/Div) VIN = 5V, ICHG = 500mA Time (1ms/Div) Time (50μs/Div) Input Standby Current vs. Input Voltage Input Shutdown Current vs.Input Voltage 200 Input Shutdown Current (μA)1 Input Standby Current (μA)1 250 200 150 100 50 VBATT = 4.5V, CIN = 1μF 0 4.0 4.3 4.6 4.9 5.2 5.5 5.8 6.1 Input Voltage (V) www.richtek.com 6 6.4 6.7 7.0 180 160 140 120 VBATT = 3.7V 100 4.0 4.3 4.6 4.9 5.2 5.5 5.8 6.1 6.4 6.7 7.0 Input Voltage (V) DS9516-01 April 2011 RT9516 Input OVP vs. Temperature 7.1 1000 7.0 Input OVP (V) Charge Current (mA) Charge Current vs. RSET 1200 800 600 400 200 6.9 6.8 6.7 6.6 VIN = 5V, VBATT = 3.7V 0 VBATT = 3.7V 6.5 1 2 3 4 5 6 7 8 9 10 11 12 13 14 -40 -20 0 20 40 60 80 100 120 Temperature (°C) RSET (kΩ) Battery Regulation Voltage vs. Temperature Battery Regulation Voltage (V) 4.190 4.185 4.180 4.175 4.170 4.165 4.160 4.155 VIN = 5V 4.150 -40 -20 0 20 40 60 80 100 120 Temperature (°C) DS9516-01 April 2011 www.richtek.com 7 RT9516 Applications Information Pre-Charge Constant Constant Mode Current Mode Voltage Mode IISET Programmed Charge 4.2V Current Battery Regulation Voltage threshold The RT9516 is a fully integrated low cost single-cell Li-Ion battery charger with a constant current (CC mode) or a constant voltage (CV mode). The CC mode current is set with the external resistor RSET and the CV mode voltage is fixed at 4.2V. If the battery voltage is below a typical 2.5V pre-charge threshold, the RT9516 charges the battery with a trickle current until the battery voltage rises above the pre-charge threshold. The RT9516 is capable of being powered up from AC adapter and USB (Universal Serial Bus) port inputs. Recharge Phase 10% Programmed Charge Current 2.5V Precharge Threshold ACIN Over-Voltage Protection The input voltage is monitored by the internal comparator. The OVP threshold is set at 7V (typ.). When the input voltage exceeds the threshold, the controller outputs a logic signal to turn off the power P-MOSFET to prevent the high input voltage from damaging the electronics in the handheld system. However, AC input voltage over 28V still leads the RT9516 to damage. When the input overvoltage condition is removed, the controller will enables the output by running through the soft-start. Charger Enable Input EN is an active-low logic input to enable the charger. Drive the EN pin to low or leave it floating to enable the charger. This pin has a 200kΩ internal pull down resistor. So when left floating, the input is equivalent to logic low. Drive this pin to high to disable the charger. Battery Charge Profile Time Figure 1 a. Battery Pre-Charge Current During a charge cycle, if the battery voltage is below the pre-charge threshold, the RT9516 applies a pre-charge mode to the battery. This feature revives deeply discharged cells and protects battery life. The internally determined pre-charge rate of the RT9516 is 10% of the constant charge current. b. Battery Fast-Charge Current The RT9516 offers ISET pin to determine the charge current. By an external resistor connected between the ISET and GND. The charge current can be calculated by the following equation : V Icharge = K SET SET R SET KSET = 1140; VSET = 1.4(typ.) Charge Current vs. RSET The RT9516 charges a Li-ion battery with a constant current (CC) or a constant voltage (CV). The constant current of ISET is set with the external resistor RSET and 1000 Charge Current (mA) the constant voltage is fixed at 4.2V. If the battery voltage is below a typical 2.5V trickle-charge threshold, the RT9516 charges the battery with a trickle current until the battery voltage rises above the trickle charge threshold. When the battery voltage reaches 4.2V, the charger enters a CV mode and regulates the battery voltage at 4.2V to fully charge the battery without the risk of over charge. 1200 800 600 400 200 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 RSET (kΩ) Figure 2 www.richtek.com 8 DS9516-01 April 2011 RT9516 c. Battery Voltage Regulation (CV Mode) Temperature Regulation and Thermal Protection The battery voltage regulation feedback is through the BATT pin. The RT9516 monitors the battery voltage between the BATT and GND pins. When battery voltage is close to battery regulation voltage threshold, the voltage regulation phase begins and the charging current begins to taper down. When battery voltage is over battery regulation voltage threshold and charge mode stops, the RT9516 still monitors the battery voltage. Charge current is resumed when the battery voltage under battery regulation voltage threshold. In order to maximize charge rate, the RT9516 features a junction temperature regulation loop. If the power dissipation of the IC results in a junction temperature that is greater than the thermal regulation threshold (115°C), the RT9516 throttles back on the charge current in order to maintain a junction temperature around the thermal regulation threshold (115°C). The RT9516 monitors the junction temperature, TJ, of the die and disconnects the battery from the input if TJ exceeds 115°C. This operation continues until junction temperature falls below thermal regulation threshold (115°C by the hysteresis level. This feature prevents the maximum power dissipation from exceeding typical design conditions. Sleep Mode The RT9516 enters the sleep mode if both AC and USB are removed from the input. This feature prevents draining the battery during the absence of input supply. Power Good The open-drain output pin is used to indicate the input voltage status. The PGOOD output asserts low when VIN > 4.25V and (VIN − VBATT) > 40mV. These PGOOD pin can be used to drive LED or communicate to the host processor. Note that ON indicates the open-drain transistor is turned on and LED is bright. Auto-Booting The RT9516 has an internal “OR” gate that generates an enable signal for system booting. The battery supplies power to the “OR” gate, the RT9516 will keep BATT pin voltage to supply the “OR” gate function when the battery isn connected at BATT pin. The first input is the AC_PG and the second input is an external signal (ABI). When the (VIN − VBATT) > 90mV, the AC_PG signal is high. The ABI signal is driven by an external system, when external signal is floating, the ABI has an internal pull low resistor. VBATT AC_PG 200k ABO ABI Figure 3 DS9516-01 April 2011 Selecting the Input and Output Capacitors In most applications, a high-frequency decoupling capacitor on the input.(1μF ceramic capacitor), placed in close proximity to the input works well. In some applications depending on the power supply characteristics and cable length, it may be necessary to add an additional 10μF ceramic capacitor to the input. The RT9516 requires a small output capacitor for loop stability. A 1μF ceramic capacitor placed between the BATT pin and GND is typically sufficient. Thermal Conderations The maximum power dissipation depends on the thermal resistance of IC package, PCB layout, the rate of surroundings airflow and temperature difference between junction to ambient. The maximum power dissipation can be calculated by following formula : PD(MAX) = (TJ(MAX) − TA ) /θJA Where T J(MAX) is the maximum operation junction temperature, TA is the ambient temperature and the θJA is the junction to ambient thermal resistance. For recommended operating conditions specification of RT9516, where TJ(MAX) is 125° C and TA is the operated ambient temperature. The junction to ambient thermal resistance θJA for WDFN-8L 2x2 package is 165°C/W on the standard JEDEC 51-3 single-layer thermal test board. www.richtek.com 9 RT9516 The maximum power dissipation at TA = 25°C can be calculated by following formula : PD(MAX) = (125°C− 25°C) / (165°C /W) = 0.606W for WDFN-8L 2x2 package The maximum power dissipation depends on operating ambient temperature for fixed T J(MAX) and thermal resistance θJA. For RT9516 package, the Figure 4 of derating curves allows the designer to see the effect of rising ambient temperature on the maximum power allowed. 0.8 Single Layer PCB Power Dissipation (W) 0.7 Layout Consideration The RT9516 is a fully integrated low cost single-cell Li-Ion battery charger ideal for portable applications. Careful PCB layout is necessary. For best performance, place all peripheral components as close to the IC as possible. A short connection is highly recommended. The following guidelines should be strictly followed when designing a PCB layout for the RT9516. ` Input capacitor should be placed close to IC and connected to ground plane. The trace of input in the PCB should be placed far away from the sensitive devices or shielded by the ground. ` The GND and exposed pad should be connected to a strong ground plane for heat sinking and noise protection. ` The connection of RSET should be isolated from other noisy traces. The short wire is recommended to prevent EMI and noise coupling. ` Output capacitor should be placed close to the IC and connected to ground plane to reduce noise coupling. 0.6 0.5 WDFN-8L 2x2 0.4 0.3 0.2 0.1 GND 0 25 50 75 100 The capacitor should be placed close to IC pin and connected to ground plane. 125 Ambient Temperature (°C) Figure 4. Derating Curves for RT9516 Package CIN VIN GND RSET ISET ABI 1 2 3 4 GND 0.0 9 8 7 6 5 BATT PGOOD EN ABO COUT The connection of resistor should be The GND should be connected to isolated from other noisy traces. The short wire is recommended to a strong ground plane for heat sinking and noise protection. prevent EMI and noise coupling. GND Figure 5. PCB Layout Guide www.richtek.com 10 DS9516-01 April 2011 RT9516 Outline Dimension D2 D L E E2 1 e SEE DETAIL A b 2 1 2 1 A A1 A3 DETAIL A Pin #1 ID and Tie Bar Mark Options Note : The configuration of the Pin #1 identifier is optional, but must be located within the zone indicated. Symbol Dimensions In Millimeters Dimensions In Inches Min Max Min Max A 0.700 0.800 0.028 0.031 A1 0.000 0.050 0.000 0.002 A3 0.175 0.250 0.007 0.010 b 0.200 0.300 0.008 0.012 D 1.950 2.050 0.077 0.081 D2 1.000 1.250 0.039 0.049 E 1.950 2.050 0.077 0.081 E2 0.400 0.650 0.016 0.026 e L 0.500 0.300 0.020 0.400 0.012 0.016 W-Type 8L DFN 2x2 Package Richtek Technology Corporation Richtek Technology Corporation Headquarter Taipei Office (Marketing) 5F, No. 20, Taiyuen Street, Chupei City 5F, No. 95, Minchiuan Road, Hsintien City Hsinchu, Taiwan, R.O.C. Taipei County, Taiwan, R.O.C. Tel: (8863)5526789 Fax: (8863)5526611 Tel: (8862)86672399 Fax: (8862)86672377 Email: [email protected] Information that is provided by Richtek Technology Corporation is believed to be accurate and reliable. Richtek reserves the right to make any change in circuit design, specification or other related things if necessary without notice at any time. No third party intellectual property infringement of the applications should be guaranteed by users when integrating Richtek products into any application. No legal responsibility for any said applications is assumed by Richtek. DS9516-01 April 2011 www.richtek.com 11