® RT9536 Linear Single Cell Li-Ion Battery Charger IC for Portable Applications General Description Features The RT9536 is a fully integrated single cell Li-ion battery charger IC ideal for portable applications. The RT9536 optimizes the charging task by using a control algorithm including pre-charge mode, fast charge mode and constant voltage mode. The input voltage range of the VIN pin can be as high as 28V. When the input voltage exceeds the OVP threshold, it will turn off the charging MOSFET to avoid overheating of the chip. In RT9536, the maximum charging current can be programmed with an external resistor. For USB application, the user can set the current to 100mA/500mA through the EN/SET pin. For the factory mode, the RT9536 can allow 4.2V or 4.35V/2.3A power pass through to support system operation. It also provides a 50mA LDO to support the power of peripheral circuit. The internal thermal feedback circuit regulates the die temperature to optimize the charge rate for all ambient temperatures. The RT9536 provides protection functions such as under voltage protection, over voltage protection for VIN supply and thermal protection for battery temperature. 28V Maximum Rating for DC Adapter Internal Integrated Power MOSFETs Support 4.2V or 4.35V/2.3A Factory Mode 50mA Low Dropout Voltage Regulator Status Pin Indicator Programmed Charging Current Under Voltage Lockout Over Voltage Protection Thermal Feedback Optimized Charge Rate RoHS Compliant and Halogen Free Applications Cellular Phones Digital Cameras PDAs and Smart Phones Portable Instruments Marking Information 03 : Product Code 03 YM DNN The RT9536 is available in a WDFN-10L 3x2 package to achieve optimized solution for PCB space and thermal considerations. YMDNN : Date Code Simplified Application Circuit VIN Adapter or USB RT9536 BATT CIN BATT PGB RISET RIEOC Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS9536-01 August 2015 COUT CHGSB ISET LDO IEOC EN/SET + BATT GND is a registered trademark of Richtek Technology Corporation. www.richtek.com 1 RT9536 Ordering Information Pin Configurations RT9536 Package Type QW : WDFN-10L 3x2 (W-Type) Lead Plating System G : Green (Halogen Free and Pb Free) VIN ISET GND LDO IEOC 1 2 3 4 5 GND (TOP VIEW) 11 10 9 8 7 6 BATT PGB CHGSB GND EN/SET Note : Richtek products are : WDFN-10L 3x2 RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020. Suitable for use in SnPb or Pb-free soldering processes. Functional Pin Description Pin No. Pin Name Pin Function 1 VIN Power Input. 2 ISET Charging Current Setting. 3, 7, GND 11 (Exposed Pad) Ground. The exposed pad must be soldered to a large PCB and connected to GND for maximum power dissipation. 4 LDO LDO Output (4.9V). This pin provides 50mA output current. 5 IEOC End-of-Charge Current Setting. The IEOC is from 5% to 5O% Ichg-fast which is programmed by the ISET pin. 6 EN/SET Enable and Operation Mode and VOUT Regulation Voltage Setting. 8 CHGSB Indicator Output for Charging Status. 9 PGB Indicator Output for Power Status. 10 BATT Battery Charge Current Output. Function Block Diagram Switch Well BATT CHGSB VIN VREF VDD IBias Base Sleep Mode IEOC IEOC Set Block PGB CC/CV/TR Multi Loop Controller Status GND Current Set Block ISET Current Set Block EN/SET 200k OVP Logic LDO LDO UVLO Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 2 is a registered trademark of Richtek Technology Corporation. DS9536-01 August 2015 RT9536 Operation The RT9536 is designed for single cell Li-Ion battery charger in portable applications. Base Circuit The Base circuit provides the internal power for VDD, VREF reference voltage and bias current. Multi-Loop Controller The Multi-Loop controller controls the operation during the charging process. The controller will make sure the battery is well charged in a suitable current, voltage, and die temperature. Status Indicator Power Switch with Switch Well Circuits The main power switch between VIN and BATT is designed to control the charge current for battery. The switch well is designed to avoid the reverse current from battery to input power. Sleep Mode When the charger is only connected to battery with no input power, the charger will enter sleep mode and the leakage current from battery to the charger will be less than 10μA for low power consumption Current Set Block The charge current is adjustable from the ISET pin with an external resistor between the ISET and GND. The Endof-Charge current is also adjustable by an external resistor connected from the IEOC pin to GND. If the charging current is less than EOC current, the CHGSB pin will be pulled high. Protection The CHGSB and PGB pin indicate the charger and power condition. During the charging process, the CHGSB pin is pulled low. When the charger is under charge done condition or abnormal condition, the CHGSB will be high impedance. The PGB pin indicates the input power status at VIN pin. When the input power is normal, the PGB pin is pulled low. Operation Mode The RT9536 provides programmable output current mode setting including USB100, USB500 and Factory mode. The operation mode is programmable through the input pulse number at EN/SET pin. Under the factory mode, besides the EN/SET is also used to set regulation to be 4.2V or 4.35V. Output current is up to 2.3A. LDO The RT9536 provides a LDO regulator to support the peripheral circuits. The output voltage is regulated to 4.9V and the maximum output current is 50mA. The protection circuits include OVP, UVLO and OTP. When the protection circuit is triggered, the main power switch will be turned of to protect the charging system. Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS9536-01 August 2015 is a registered trademark of Richtek Technology Corporation. www.richtek.com 3 RT9536 Absolute Maximum Ratings (Note 1) Supply Input Voltage, VIN ----------------------------------------------------------------------------------------------- −0.3V to 28V Other Pins ------------------------------------------------------------------------------------------------------------------- −0.3V to 6V Power Dissipation, PD @ TA = 25°C WDFN-10L 3x2 ------------------------------------------------------------------------------------------------------------Package Thermal Resistance (Note 2) WDFN-10L 3x2, θJA ------------------------------------------------------------------------------------------------------WDFN-10L 3x2, θJC ------------------------------------------------------------------------------------------------------Lead Temperature (Soldering, 10 sec.) ------------------------------------------------------------------------------Junction Temperature ----------------------------------------------------------------------------------------------------Storage Temperature Range -------------------------------------------------------------------------------------------- Recommended Operating Conditions 2.27W 44°C/W 11°C/W 260°C 150°C −65°C to 150°C (Note 3) Supply Input Voltage, VIN ----------------------------------------------------------------------------------------------- 4.3V to 5.5V Junction Temperature Range -------------------------------------------------------------------------------------------- −40°C to 125°C Ambient Temperature Range -------------------------------------------------------------------------------------------- −20°C to 85°C Electrical Characteristics (VIN = 5V, VBATT = 4V, TA = 25°C, unless otherwise specified) Parameter VIN POR Rising Threshold Voltage Symbol Test Conditions Min Typ Max Unit 3.15 3.3 3.45 V -- 200 300 mV 6.7 6.9 7.1 V -- 200 300 mV VIN VOUT VOS Rising -- 75 150 mV VIN VOUT VOS Falling 18 32 -- mV VPOR VIN POR Threshold Voltage Hysteresis VIN OVP Threshold Voltage VIN OVP Threshold Voltage Hysteresis VOVP VIN Standby Current VBATT = 4.5V, EN/SET = High -- 250 300 A VIN Supply Current VBATT = 4.5V, EN/SET = Low -- 1 2 mA -- 1 10 A 4.158 4.2 4.242 4.307 4.35 4.393 Thermal Regulation -- 125 -- C OTP -- 155 -- C OTP Hysteresis -- 20 -- C PGB/CHGSB Sink Current 20 -- -- mA VOUT Rising; VCV = 4.2V 2.4 2.5 2.6 VOUT Rising; VCV = 4.35V 2.5 2.6 2.7 -- 25 -- VOUT Sleep Leakage Current VOUT Regulation Pre-Charge Threshold VCV 0C to 85C, ILOAD = 0mA Fast-Charge to Pre-Charge Deglitch Time Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 4 V V ms is a registered trademark of Richtek Technology Corporation. DS9536-01 August 2015 RT9536 Parameter Symbol IPRECHG Pre-Charge Current Test Conditions Min Typ Max Unit USB100 Mode 90 95 100 mA USB500 Mode or ISET Mode, ratio of fast-charge current 15 20 25 % -- % 70 REOC / KEOC 75 80 A 180 200 220 /% -- 280 512 mV -- 1.5 -- V 320 -- 460 -- 1.5 -- ms -- 2 -- A As ISET Mode, RISET = 530 0.9 1 1.1 A As USB100 Mode 90 95 100 mA As USB500 Mode 380 395 415 mA -- 200 -- k End of Charge Current (EOC) IEOC Setting Current -IEOC IEOC Setting KEOC VIN Power FET RDS(ON) ISET Set Voltage IOUT = 1A VISET ISET Short Protect Threshold ISET Short Protect Deglitch Time ISET Short Protect Maximum Current VIN Charge Current ICHRG EN/SET Pull Low Resistor EN/SET Voltage Logic-High VIH 1.4 -- -- Logic-Low VIL -- -- 0.4 3 6 4.75 4.9 5.05 V 60 120 180 mA VCV = 4.2V 4.116 4.2 4.284 VCV = 4.35V 4.263 4.35 4.437 2.3 -- -- A 2 -- -- ms 1.5 -- -- ms Logic-High 100 -- 700 Logic-Low 100 -- 700 750 -- 1000 LDO On-Resistance RDS(ON) LDO Output Voltage VLDO LDO Maximum Output Current Factory Mode VOUT Factory Mode Maximum Output Current EN/SET Off Time Timer to disable chip EN/SET Lock Time Timer to lock pulse count EN/SET Duration EN/SET Set Time Timer to set VCV = 4.35V V V s s Note 1. Stresses beyond those listed “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and 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 may affect device reliability. Note 2. θJA is measured at TA = 25°C on a high effective thermal conductivity four-layer test board per JEDEC 51-7. θJC is measured at the exposed pad of the package. Note 3. The device is not guaranteed to function outside its operating conditions. Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS9536-01 August 2015 is a registered trademark of Richtek Technology Corporation. www.richtek.com 5 RT9536 Typical Application Circuit RT9536 1 VIN Adapter or USB BATT 10 CIN BATT COUT 9 PGB CHGSB 8 2 LDO 4 EN/SET 6 3, 7, 11 (Exposed Pad) GND 5 RISET RIEOC Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 6 + ISET IEOC BATT is a registered trademark of Richtek Technology Corporation. DS9536-01 August 2015 RT9536 Typical Operating Characteristics VOUT Regulation Voltage vs. Input Voltage VOUT Regulation Voltage vs. Temperature 4.215 4.220 4.215 4.210 4.205 4.200 VCV = 4.2V VOUT Regulation Voltage (V)1 VOUT Regulation Voltage (V) 4.225 4.210 4.205 4.200 4.195 4.190 VCV = 4.2V, VIN = 5V 4.185 4.195 4.5 4.94 5.38 5.82 6.26 -50 6.7 -25 0 VOUT Regulation Voltage vs. Input Voltage 75 100 125 VOUT Regulation Voltage vs. Temperature VOUT Regulation Voltage (V) VOUT Regulation Voltage (V)1 50 4.370 4.370 4.366 4.362 4.358 4.354 4.365 4.360 4.355 4.350 4.345 VCV = 4.35V VCV = 4.35V 4.340 4.350 4.5 4.94 5.38 5.82 6.26 -50 6.7 -25 0 Input Voltage (V) Input OVP Threshold vs. Temperature 6.80 6.78 6.76 6.74 6.72 6.70 -25 0 25 50 75 100 Temperature (°C) Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS9536-01 August 2015 50 75 100 125 VOUT Sleep Leakage Current vs. Battery Voltage VOUT Sleep Leakage Current (µA)1 6.82 -50 25 Temperature (°C) 6.84 Input OVP Threshold (V) 25 Temperature (°C) Input Voltage (V) 125 20 16 12 8 4 0 1.3 1.7 2.1 2.5 2.9 3.3 3.7 4.1 4.5 Battery Voltage (V) is a registered trademark of Richtek Technology Corporation. www.richtek.com 7 RT9536 LDO Voltage vs. Temperature 4.95 4.93 4.93 LDO Voltage (V) LDO Output Voltage (V) LDO Output Voltage vs. Output Current 4.95 4.91 4.89 4.91 4.89 4.87 4.87 VIN = 5.5V, ILDO = 50mA VIN = 5.5V 4.85 4.85 0 20 40 60 80 100 -50 -25 Output Current (mA) 0 25 50 75 100 125 Temperature (°C) ISET Mode Charge Current vs. Input Voltage USB 500 Mode Charge Current vs. Input Voltage 900 415 R = 680 750 Charge Current (mA) Charge Current (mA) 825 675 600 525 450 R = 1.2k 405 395 385 375 375 VBATT = 3.8V VBATT = 3.8V 300 365 4.5 4.9 5.3 5.7 6.1 6.5 4.5 4.9 Input Voltage (V) 5.3 5.7 6.1 6.5 Input Voltage (V) USB 100 Mode Charge Current vs. Input Voltage ISET Voltage vs. Input Voltage 100 1.53 ISET Voltage (V) Charge Current (mA) 1.52 95 90 1.51 1.50 1.49 1.48 RISET = 1.2kΩ, VBATT = 3.8V VBATT = 3.8V 85 1.47 4.5 4.9 5.3 5.7 6.1 Input Voltage (V) Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 8 6.5 4.2 4.72 5.24 5.76 6.28 6.8 Input Voltage (V) is a registered trademark of Richtek Technology Corporation. DS9536-01 August 2015 RT9536 Power On EN/SET Shut-Down VIN (5V/Div) EN/SEB (1V/Div) PGB (2V/Div) CHGSB (2V/Div) VLDO (2V/Div) CHGS (2V/Div) I CHARGER (500mA/Div) I CHARGER (500mA/Div) VBATT = 3.8V, RISET = 680Ω, EN/SEB = Low VIN = 5V Time (10ms/Div) Charger Current--USB500 mode to ISET mode Time (1ms/Div) Charger Current--USB500 mode to USB100 mode VIN (5V/Div) VBATT (5V/Div) EN/SET (2V/Div) VIN (5V/Div) VBATT (5V/Div) EN/SET (2V/Div) I CHARGER (500mA/Div) I CHARGER (500mA/Div) VIN = 5V, VBATT = 3.8V, RISET = 680Ω VIN = 5V, VBATT = 3.8V, RISET = 680Ω Time (1ms/Div) Time (1ms/Div) LDO Load Transient Response Factory Mode VIN (5V/Div) VBATT (200mV/Div) EN/SET (1V/Div) VLDO_ac (100mV/Div) I LDO (500mA/Div) IOUT (1A/Div) VIN = 5V, VBATT = 3.8V, ILDO = 5mA to 50mA Time (250μs/Div) Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS9536-01 August 2015 VIN = 5V, COUT = 44μF, IOUT = 10Ω to 2.3Ω Time (50μs/Div) is a registered trademark of Richtek Technology Corporation. www.richtek.com 9 RT9536 Application Information Description The RT9536 is a fully integrated low cost single-cell LiIon battery charger IC with a Constant Current mode (CC mode) or a Constant Voltage mode (CV mode). The charge current is programmable to USB100, USB500 or ISET mode and the CV mode voltage is fixed at 4.2V/4.35V. The pre-charge threshold is fixed at 2.5V/2.64V. If the battery voltage is below the pre-charge threshold, the RT9536 charges the battery with a trickle current until the battery voltage rises above the pre-charge threshold. The RT9536 is capable of being powered up from AC adapter and USB (Universal Serial Bus) port inputs. Moreover, the RT9536 include a linear regulator (LDO 4.9V, 50mA) for supplying low power external circuitry. period of pulse to pulse must be between 100μs and 700μs to be properly read. Once EN/SET is held low for 1.5ms, the number of pulses is locked and sent to the control logic and then the mode changes. After the setting of charging current is completed, sending the pulse can set CV mode voltage to be 4.35V. The RT9536 needs to be restarted to reset the charge current. Once the EN/SET input is held high for more than 2ms, the RT9536 is disabled. A. USB500 Mode with CV = 4.2V No pulse to set USB500 mode EN/SET 50µs tHigh Four pulses to set USB500 mode EN/SET ACIN Over Voltage Protection The input voltage is monitored by the internal comparator and the input over voltage protection threshold is set to 6.9V. However, input voltage over 28V will still cause damage to the RT9536. When the input voltage exceeds the threshold, the comparator 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. When the input over voltage condition is removed, the comparator re-enables the output by running through the soft-start. Charger Enable and mode Setting EN/SET is used to enable or disable the charger as well as to select the charge current limit. Drive the EN pin to low or leave it floating to enable the charger. The EN/SET 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. After the EN/SET pin pulls low for 50μs, the RT9536 enters the USB500 mode and wait for the setting current signal. EN/SET can be used to program the charge current during this cycle. The RT9536 will change its charge current by sending different pulse to EN/SET pin. If no signal is sent to EN/SET, the RT9536 will remain in USB500 mode. A correct period of time for high pulse is between 100μs and 700μs and the Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 10 tLow B. ISET Mode with CV = 4.2V 50µs tHigh One pulse to set ISET mode EN/SET C. USB100 Mode with CV = 4.2V 50µs tHigh Two pulses to set USB100 mode EN/SET tLow D. PTM Mode with CV = 4.2V 50µs tHigh Three pulses to set PTM mode EN/SET tLow 100μs < tHigh < 700μs 100μs < tLow < 700μs Figure 1 (a). CV is 4.2V is a registered trademark of Richtek Technology Corporation. DS9536-01 August 2015 RT9536 E. USB500 Mode with CV = 4.35V 50µs tCV_Set tHigh EN/SET Four pulses to set USB500 mode Besides, wait the time, tWait and send a pulse of tCV_SET width for CV = 4.35V tWait tLow F. ISET Mode with CV = 4.35V 50µs One pulse to set ISET mode Besides, wait the time, tWait and send a tHigh tCV_Set EN/SET pulse of tCV_SET width for CV = 4.35V tWait G. USB100 Mode with CV = 4.35V 50µs tHigh tCV_Set EN/SET Two pulses to set USB100 mode Besides, wait the time, tWait and send a pulse of tCV_SET width for CV = 4.35V tWait H. PTM Mode with CV = 4.35V 50µs tHigh tCV_Set Three pulses to set PTM mode Besides, wait the time, tWait and send a pulse of tCV_SET width for CV = 4.35V EN/SET tLow tWait 100μs < tHigh < 700μs, 100μs < tLow < 700μs, 1.5ms < tWait 750μs < tCV_Set < 1ms Figure 1 (b). CV is 4.35V Table 1. Pulse Counting Map for EN/SET Interface Pulses Charge Condition MODE Control 0 USB500 Mode Charge Current Limit 1 ISET Mode Charge Current Limit 2 USB100 Mode Charge Current Limit 3 Factory Mode Enabled 4 USB500 Mode Charge Current Limit Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS9536-01 August 2015 is a registered trademark of Richtek Technology Corporation. www.richtek.com 11 RT9536 Battery Charge Profile Battery Fast-Charge Current The RT9536 charges a Li-Ion battery with a Constant Current (CC) or a Constant Voltage (CV). ISET Mode The constant current is decided by the operation mode of USB100, USB500 or ISET mode. The constant current is set with the external resistor RISET and the constant voltage is fixed at 4.2V/4.35V. If the battery voltage is below the Pre-Charge Threshold, the RT9536 charges the battery with a trickle current until the battery voltage rises above the trickle charge threshold. When the battery voltage reaches 4.2V/4.35V, the charger enters CV mode and regulates the battery voltage at 4.2V/4.35V to fully charge the battery without the risk of over charging 1400 Constant Current Mode Battery Charge Current Programmed Charge Current Constant Voltage Mode Recharge Phase 4.2V/4.35V Battery Regulation Voltage threshold Battery Charge Current (mA) Pre-charge Mode The RT9536 offers ISET pin to program the charge current. The resistor RISET is connected to ISET and GND. The parameter KISET is specified in the specification Table. K ICharge = ISEF ; KISEF = 530 RISET 1200 1000 800 600 400 200 0 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 3 RSET (k) (kΩ) Figure 3 Battery Full CHG_S pull High USB500 and USB100 Mode Precharge Threshold Time Figure 2 The fast-charge current is 95mA in USB100 mode and 395mA in USB500 mode. Note that if the fast-charge current set by external resistor is smaller than that in USB500 mode (395mA), the RT9536 charges the battery in ISET mode. Battery Voltage Regulation (CV Mode) Battery Pre-Charge Current During a charge cycle, if the battery voltage is below the pre-charge threshold, the RT9536 enters the pre-charge mode. This feature revives deeply discharged cells and protects battery. Under USB100 Mode, the pre-charge current is internally set to 95mA. When the RT9536 is under USB500 and ISET Mode, the pre-charge current is 20% of fast-charge current set by external resistor RISET. Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 12 The battery voltage regulation feedback is through the BATT pin. The RT9536 monitors the battery voltage between BATT and GND pins. When the battery voltage closes in on the battery regulation voltage threshold, the voltage regulation phase begins and the charging current begins to taper down. When the charging current falls below the programmed end-of-charge current threshold, the CHGSB pin goes high to indicate the termination of charge cycle. is a registered trademark of Richtek Technology Corporation. DS9536-01 August 2015 RT9536 The end-of-charge current threshold is set by the IEOC pin. The resistor REOC is connected to IEOC and GND. The parameters KEOC and IEOC are specified in the specification Table. R IEOC (%) = EOC ; KEOC = 200 KEOC The current threshold of IEOC (%) is defined as the percentage of fast-charge current set by RISET. After the CHGSB pin is pulled high, the RT9536 still monitors the battery voltage. Charge current is resumed when the battery voltage goes to lower than the battery regulation voltage threshold. Factory Mode The RT9536 provides factory mode for supplies up to 2.3A for powering external loads with no battery installed and BATT is regulated to 4.2V. The factory mode allows the user to supply system power with no battery connected. In factory mode, thermal regulation is disabled but thermal protection (155°C) is still active. When using currents greater than 1.5A in factory mode, the user must limit the duty cycle at the maximum current to 20% with a maximum period of 10ms. LDO The RT9536 integrates one low dropout linear regulator (LDO) that supplies up to 50mA. The LDO is active whenever the input voltage is between POR threshold and OVP threshold. It is not affected by the EN/SET input. Note that the LDO current is independence and not monitored by the charge current limit. Charge Status Outputs (CHGSB and PGB) The open-drain CHGSB and PGB outputs indicate various charger operations as shown in the following Table. These status pins can be used to drive LEDs or communicate to the host processor. Note that ON indicates the open-drain transistor is turned on and LED is bright. Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS9536-01 August 2015 Table 2 Condition CHGSB Input OVP OFF Input UVLO OFF Charge (CC Mode and CV Mode) ON Charge Done (IFULL) OFF PGB OFF OFF ON ON PGB Deglitches Time Condition EN/SET is High EN/SET is Low 0 100s 500s 450s 0 32ms 500s 500s Entering UVLO (VIN = 5.5V2.5V) 0 0 Leaving UVLO (VIN = 2.5V5.5V) 230s 230s Entering OVP (VIN = 5.5V10V) Leaving OVP (VIN = 10V5.5V) Entering SLEEP (VIN = 5.5V3.6V) Leaving SLEEP (VIN = 3.6V5.5V) Sleep Mode The RT9536 enters sleep mode if the power is removed from the input. This feature prevents draining the battery during the absence of input supply. Temperature Regulation and Thermal Protection In order to maximize charge rate, the RT9536 features a junction temperature regulation loop. If the power dissipation of the IC results in a junction temperature greater than the thermal regulation threshold (125°C), the RT9536 limits the charge current in order to maintain a junction temperature around the thermal regulation threshold (125°C). The RT9536 monitors the junction temperature, TJ, of the die and disconnects the battery from the input if TJ exceeds 125°C. This operation continues until junction temperature falls below thermal regulation threshold (125°C) by the hysteresis level. This feature prevents maximum power dissipation from exceeding typical design conditions. is a registered trademark of Richtek Technology Corporation. www.richtek.com 13 RT9536 2.5 Maximum Power Dissipation (W)1 Selecting the Input and Output Capacitors In most applications, all that is needed is a high-frequency decoupling capacitor on the input. A 1μF ceramic capacitor, placed in close proximity to input to GND, 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 RT9536 requires a small output capacitor for loop stability. A typical 1μF ceramic capacitor placed between the BATT pin and GND is sufficient. Four-Layer PCB 2.0 1.5 1.0 0.5 0.0 0 Thermal Considerations PD(MAX) = (TJ(MAX) − TA) / θJA where T J(MAX) is the maximum operation junction temperature, TA is the ambient temperature, and θJA is the junction to ambient thermal resistance. For recommended operating condition specifications, the maximum junction temperature is 125°C. The junction to ambient thermal resistance, θJA, is layout dependent. For WDFN-10L 3x2 package, the thermal resistance, θJA, is 44°C/W on a standard JEDEC 51-7 four-layer thermal test board. The maximum power dissipation at TA = 25°C can be calculated by the following formula : P D(MAX) = (125°C − 25°C) / (44°C/W) = 2.27W for WDFN-10L 3x2 package The maximum power dissipation depends on the operating ambient temperature for fixed T J(MAX) and thermal resistance, θJA. The derating curve in Figure 4 allows the designer to see the effect of rising ambient temperature on the maximum power dissipation. 50 75 100 125 Ambient Temperature (°C) Figure 4. Derating Curve of Maximum Power Dissipation Layout Consideration The RT9536 is a fully integrated low cost single-cell LiIon battery charger IC 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 RT9536. Input capacitor should be placed close to the 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 should be connected to a strong ground plane for heat sinking and noise protection. The connection of RISET and RIEOC 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. The capacitor should be placed close to IC pin and connected to ground plane. The connection of resistor should be isolated from other noisy traces. Short wire is recommended to prevent EMI and noise coupling. CIN RISET VIN ISET GND LDO IEOC 1 2 3 4 5 GND For continuous operation, do not exceed absolute maximum operation junction temperature. The maximum power dissipation depends on thermal resistance of the IC package, PCB layout, rate of surrounding airflow, and difference between junction and ambient temperature. The maximum power dissipation can be calculated by the following formula : 25 11 10 9 8 7 6 BATT PGB CHGSB GND EN/SET COUT RIEOC GND The GND should be connected to a strong ground plane for heat sinking and noise protection. Figure 5. Layout Guide Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 14 is a registered trademark of Richtek Technology Corporation. DS9536-01 August 2015 RT9536 Outline Dimension D2 D L E2 E 1 e A A1 SEE DETAIL A b A3 2 1 2 1 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 0.180 0.300 0.007 0.012 D 2.900 3.100 0.114 0.122 D2 2.450 2.550 0.096 0.100 E 1.900 2.100 0.075 0.083 E2 0.750 0.850 0.030 0.033 e L 0.500 0.250 0.020 0.350 0.010 0.014 W-Type 10L DFN 3x2 Package Richtek Technology Corporation 14F, No. 8, Tai Yuen 1st Street, Chupei City Hsinchu, Taiwan, R.O.C. Tel: (8863)5526789 Richtek products are sold by description only. Richtek reserves the right to change the circuitry and/or specifications without notice at any time. Customers should obtain the latest relevant information and data sheets before placing orders and should verify that such information is current and complete. Richtek cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Richtek product. Information furnished by Richtek is believed to be accurate and reliable. However, no responsibility is assumed by Richtek or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Richtek or its subsidiaries. DS9536-01 August 2015 www.richtek.com 15