RT4832AWSC

RT4832A Sub PMIC with Dual-Output Boost Converter with I2C Interface for Flash LED and Backlight LED, Dual-Output LCD Bias and DSV General Description The RT4832A is an integrated total power solution for Flash LED Driver, Backlight WLED Driver, and DSV Driver. Flash LED Driver provides up to 2-CH 1.5A applications. Back Light WLED Driver supports up to 36V output for 10 WLEDs applications. And it provides 1024 steps LED current with logarithmic/linear curve. DSV is implemented by one single inductor boost and inverting charge pump, which provide customers minimum EVB area compared to dual inductors. The negative output power (CPOUT) comes from boost output (LCMOUT). It also provides DSV positive voltage (POS), which power noise is reduce by passing though LDO. Their ranges can be programmed from ±4V to ±6V per 50mV step respectively. Flash Boost Converter operates at 2MHz/4MHz frequency. The 4MHZ frequency solution allows tinny and low-profile components. Torch Mode Current can be set from Features       25mA to 375mA per 25mA step. And Strobe Mode Current range is from 100mA to 1.5A per 100mA step. DSV drives TFT-LCD panels up to 10” (from SFF to MFF like tablets). These two output rails are usually connected to Source Driver IC. Wide input voltage range from 2.5V to 5.5V optimizes the single-cell battery applications (Li-Ion, Ni-Li, Li-Polymer) and which symmetrical output current is up to 80mA. The RT4832A provides complete protection such as VIN under voltage lockout, Vin monitor protection, over current protection, over voltage protection, LED short protection, VOUT short protection and over temperature protection. The RT4832A is available in WL-CSP-30B 2.24x2.64 (BSC) package. Applications   Smart Phones Probable Instruments Copyright © 2017 Richtek Technology Corporation. All rights reserved. DS4832A-00 January 2017 Input Voltage Range : 2.5V to 5.5V Internal Soft-start, UVLO, OTP, OCP Typical Shutdown Current : < 1A 40 to 85°C Temperature Range 2CH Back Light LED Driver  Drives Up to 10 WLEDs in Two Strings 2  External PWM Pin Control and I C Programmable 11 bit Linear and Exponential Brightness  LED Current Accuracy 5% (>500A), 3% (>5mA) 2  I C Programmable OVP 18/22/25/29/33/36V 2CH Flash LED Driver  Torch Mode Current from 25mA to 375mA per 25mA Step with 2 Channels  Strobe Mode Current from 100mA to 1.5A per 100mA Step with 2 Channels 2  I C Programmable Flash Safety Timer from 32ms to 1024ms per 32ms Step  High Accurate Safety Timer ±10%, Current Accuracy 4% (>375mA), Current Matching 7% (>375mA)  VIN Monitor Protection from 2.5V to 3.2V per      0.1V Step Selectable Input Current Limit 1.9/2.8A 2MHz/4MHz Switching Frequency for Flash LED Flash LED1/2 Short Protection, and Output Short Protection Txmask Protection by Independent Pin DSV 2  I C Programmable Output Voltages  Flexible Boost Voltage, POS, CPOUT Default Setting  Regulated Voltage Output : 4V to 6V per 50mV Step  Positive Voltage Output : 4 to 6V per 50mv Step  Negative Voltage Output : 4 to 6V per 50mV Step  User Selectable Output Fast Discharge Mode or is a registered trademark of Richtek Technology Corporation. www.richtek.com 1 RT4832A   Float Mode when Turned Off Independent Positive and Negative Enable Control by Two External Pins Marking Information True Load Disconnect, OCP, and Positive/Negative SCP Function 0X : Product Code YMDNN : Date Code 0X YM DNN Ordering Information Pin Configuration RT4832A Package Type WSC : WL-CSP-30B 2.24x2.64 (BSC) (TOP VIEW) Note : A1 POS Richtek products are :  RoHS compliant and compatible with the current A3 A4 A5 LCM SW LED GND LED SW B1 B2 B3 B4 B5 ENM ENP EN LCM GND LED OUT requirements of IPC/JEDEC J-STD-020.  A2 LCM OUT Suitable for use in SnPb or Pb-free soldering processes. C1 C2 C3 C1 SDA Txmask D1 D2 D3 D4 D5 CP GND C4 AGND C5 LED1 STRB PWM LED2 E1 E2 E3 E4 E5 C2 Flash LED Flash OUT Flash SW VIN SCL F1 F2 F3 CP OUT Flash LED Flash OUT F4 Flash SW F5 Flash GND WL-CSP-30B 2.24x2.64 (BSC) Typical Application Circuit L2 10μH D1 L1 0.47μH to 1μH E5 B3 D4 D3 C3 D2 C2 FlashSW VIN EN PWM STRB Txmask SCL SDA B2 ENP B1 ENM L3 2.2μH A3 LCMSW C2 4.7μF C1 E1 C1 LCMOUT A2 POS FlashLED F1 CPOUT C6 10μF Copyright © 2017 Richtek Technology Corporation. All rights reserved. AGND FlashGND C2 2P10S WLEDs LED1 C5 D5 LED2 FlashOUT E3, F3 LEDGND C5 10μF www.richtek.com 2 LEDSW A5 LEDOUT B5 …… E4, F4 C1 10μF VIN C8 2.2μF RT4832A …… VIN LED1 CPGND C3 10μF C7 10μF A1 E2, F2 A4 C4 10μF C4 F5 D1 LCMGND B4 U1 is a registered trademark of Richtek Technology Corporation. DS4832A-00 January 2017 RT4832A Reference Part Number Value Description C1, C3, C4, C5, C6, C7 C2012X7R1A106KT0AHE 10F/10V/X5R Ceramic capacitor C2 C2012X7R1A475KT0AHE 4.7F/10V/X5R Ceramic capacitor C8 UMK316BJ225KD-T 2.2F/50V/X7R Ceramic capacitor L1 NR4018T1R0N 1H Inductor L2 NR4018T100M 10H Inductor L3 NR4018T2R2M 2.2H Inductor D1 SS14 40V/1A Schottky diode Timing Diagram SDA VIH( MIN) VIL( MAX) tSU, DAT tLOW SCL tHD, DAT tHIGH tSU, STO tBUF VIH( MIN) VIL( MAX) tHD, STA tf S Copyright © 2017 Richtek Technology Corporation. All rights reserved. DS4832A-00 January 2017 P S is a registered trademark of Richtek Technology Corporation. www.richtek.com 3 RT4832A Functional Pin Description Pin No. Pin Name Pin Function A1 POS Positive terminal LDO output. Connect a 10F ceramic capacitor between this pin and Ground. A2 LCMOUT DSV boost converter output pin. Connect a 10F ceramic capacitor between this pin and Ground. A3 LCMSW Switching node of DSV boost converter. Connect a 2.2μH inductor between LCMSW and VIN. A4 LEDGND Back light LED ground. A5 LEDSW Switch node of boost converter. Connect a 4.7H to 10H inductor between LEDSW and VIN. B1 ENM Enable the CPOUT. B2 ENP Enable the POS. B3 EN Chip enable. B4 LCMGND DSV boost converter ground pin. B5 LEDOUT Back light LED boost output pin. C1 C1 Fly capacitor 1 positive connection of inverter charge pump. C2 SDA I2C serial data input/output. An external pull-up resistor is required. C3 Txmask Configurable power amplifier synchronization input or configurable active high torch enable. Has an internal pull-down resistor of 400k between TX and ground. C4 AGND Analog ground. C5 LED1 Single output 1 for backlight LED. D1 CPGND Inverter charge pump ground. D2 SCL I2C serial clock input. An external pull-up resistor is required. D3 STRB Active high hardware flash enable. Drive STRB high to turn on flash pulse. Has an internal pull-down resistor of 400k between STRB and ground. D4 PWM PWM dimming input for backlight LED. D5 LED2 Single output 2 for backlight LED. E1 C2 Fly capacitor 1 negative connection of inverter charge pump. Connect a 10F ceramic capacitor between this pin and C1. E2, F2 FlashLED High-side current source output for flash LED. E3, F3 FlashOUT Step-up flash DC-DC converter output. Connect a 10F ceramic capacitor between this pin and Ground. E4, F4 FlashSW Drain connection for internal N-MOSFET and synchronous P-MOSFET switches. Connect a 0.47 to 1H inductor between FlashSW and VIN. E5 VIN Input voltage connection. Connect VIN to the input supply, and bypass to Ground with a 10F or larger ceramic capacitor. F1 CPOUT Charge pump negative terminal output. Connect a 10F ceramic capacitor between this pin and ground. F5 FlashGND Flash boost power ground. Copyright © 2017 Richtek Technology Corporation. All rights reserved. www.richtek.com 4 is a registered trademark of Richtek Technology Corporation. DS4832A-00 January 2017 RT4832A Functional Block Diagram VIN UVLO OTP OVP LEDOUT Vrb LEDSW BL PWM/Drv Back Light DC to DC Core EN LEDGND PWM RC Control Logic OCP Vrb MINFB PWM VrF OSC LED2 Flash Light DC to DC Core Current Source LED1 SDA fledsh VrF FlashLED SCL MINFB ENM LED Short Current Source POR FlashLED OVP ENP APR FlashOUT Vin Monitor Output Short Txmask Back Gate Control STRB FlashSW FL PWM/Drv fledsh VrLCM FlashGND OCP POS LCM DC to DC Core POS SCP LDO LCMOUT AGND C1 C2 X1 Negative Charge Pump fledsh LCM PWM/Drv Back Gate Control LCMSW CPOUT OCP NEG SCP LCMGND CPGND Copyright © 2017 Richtek Technology Corporation. All rights reserved. DS4832A-00 January 2017 is a registered trademark of Richtek Technology Corporation. www.richtek.com 5 RT4832A Absolute Maximum Ratings (Note 1)  Supply Voltage (VIN) --------------------------------------------------------------------------------------------------0.3V to 6V  LED Boost Output Voltage (LEDOUT) ----------------------------------------------------------------------------0.3V to 37V  LED Switching Voltage (LEDSW) ----------------------------------------------------------------------------------0.3V to 37V  LED Current Source Voltage (LED1, LED2) ---------------------------------------------------------------------0.3V to 36V  LCM Boost Output Voltage (LCMOUT, POS) -------------------------------------------------------------------0.3V to 6.3V  LCM Switching Voltage (LCMSW, C1) ----------------------------------------------------------------------------0.3V to 6.3V  Negative Charge Pump Switching Voltage (C2) ----------------------------------------------------------------0.3V to 6.5V  Negative Charge Pump Voltage (CPOUT) -----------------------------------------------------------------------0.3V to 6.5V  Flash Switching Voltage (FlashSW) -------------------------------------------------------------------------------0.3V to 6V  Flash Output Voltage (FlashOUT)----------------------------------------------------------------------------------0.3V to 6V  Flash LED Voltage (FlashLED) -------------------------------------------------------------------------------------0.3V to 6V  Digital Clock Control Pins (SDA, SCL, PWM) -------------------------------------------------------------------0.3V to 6V  Other Pins (EN, ENM, ENP, Txmask, STRB) -------------------------------------------------------------------0.3V to 6V  Power Dissipation, PD @ TA = 25C WL-CSP-30B 2.24x2.64 (BSC) ------------------------------------------------------------------------------------ 3.15W  Package Thermal Resistance (Note 2) WL-CSP-30B 2.24x2.64 (BSC), JA ------------------------------------------------------------------------------ 31.7C/W  Lead Temperature (Soldering, 10 sec.) -------------------------------------------------------------------------- 260C  Junction Temperature ------------------------------------------------------------------------------------------------ 150C  Storage Temperature Range --------------------------------------------------------------------------------------- 65C to 150C  ESD Susceptibility (Note 3) HBM (Human Body Model) ----------------------------------------------------------------------------------------- 2kV Recommended Operating Conditions (Note 4)  Supply Voltage, VIN -------------------------------------------------------------------------------------------------- 2.5V to 5.5V  Ambient Temperature Range--------------------------------------------------------------------------------------- 40C to 85C  Junction Temperature Range -------------------------------------------------------------------------------------- 40C to 125C Electrical Characteristics (VIN = 3.6V, CVIN = 10F, TA = 25C, unless otherwise specified) Parameter Symbol Test Conditions Min Typ Max Unit 2.5 -- 5.5 V Power Supply Input Voltage Range VIN UVLO UV VIN falls -- 2.2 2.3 V UVLO Hysteresis Voltage UVhys 30 50 200 mV VIN Supply Current IQ VIN rises after UVLO LCD Bias enable, Back Light turned off, EN = H, LCMOUT = 5.2V -- 0.5 -- mA VIN Shutdown Current ISHDN VIN = 5V, EN = L -- 1 -- A Thermal Shutdown TSD -- 145 -- C Copyright © 2017 Richtek Technology Corporation. All rights reserved. www.richtek.com 6 is a registered trademark of Richtek Technology Corporation. DS4832A-00 January 2017 RT4832A Parameter Thermal Shutdown Hysteresis Symbol Test Conditions TSDHYS Min Typ Max Unit -- 15 -- C Flash LED Accuracy of Flash Output Current 1/2 AIFL1 IFLED > 375mA 4 -- 4 AIFL2 IFLED = 25mA to 375mA 10 -- 10 FLED Sense Voltage 1/2 VDSFL FlashOUT FlashLED, IFLED = 750mA (per channel) -- 300 -- mv Flash 1/2 Start-up Current IFLST FlashOUT = 3.6V, FlashLED to Ground (per channel) 2 2.5 4 mA Flash Pre-charge Current IFLPRE FlashOUT = VIN  0.15V 40 150 300 mA Flash Switching Frequency f FOSC 0x07[7:6] = 01 1.8 2 2.2 MHz Safety Timeout tOUT 0x07[4:0] = 10000, Strb goes high until 0x0B[1] = 01 460 512 563 ms Maximum Duty Cycle DmaxFL 0x07[6] = 01 -- 70 -- % Flash N-MOSFET Ron RonFLN 20 65 130 m Flash P-MOSFET Ron RonFLP 20 80 160 m FlashOUT = 3.6V % Flash N-MOSFET Current Limit IOCPFL 0x07[5] = 1 2.24 2.8 3.36 A VIN Monitor Voltage VIN falls until 0x0B[4] = 01, 0x08[2:0] = 100, 0x09[0] = 1 2.82 2.9 2.98 V VIN Monitor Hysteresis Voltage VMONhys VIN rises until 0x0B[4] = 10, 0x08[2:0] = 100, 0x09[0] = 1 1 5 -- % Flash Output Short Voltage VFLSH FlashOUT < 1.5V for 1msec, 0x0B[5] = 01 0 -- 1.5 V Flash LED 1/2 Short Voltage VFLEDSH FlashLED < 1.5V for 1msec, 0x0B[2] = 01 (per channel) 0 -- 1.5 V Flash Over Voltage Protection VFLOVP FlashOUT > VIN, 0x0B[6] = 01 5 5.3 5.6 V Accuracy of Back Light Output Current 1/2 AIBL1 IBLED = 5mA to 25mA 3 -- 3 AIBL2 IBLED = 0.5mA to 5mA 5 -- 5 Matching of Output Current MIBL IBLED = 5mA to 25mA 3 -- 3 % BLED Sense Voltage 1/2 VDSBL VIN = 3V, IFBx = 25mA -- 500 -- mV Back Light Switching Frequency fblosc 0x03[7] = 1 0.9 1 1.1 MHz Maximum Duty Cycle DmaxBL 0x03[7] = 1 90 93 -- % Back Light N-MOSFET Ron RonBLN 100 270 400 m Back Light Current Limit IOCPBL 0.96 1.2 1.44 A Back Light Over Voltage Protection VBLOVP 0x02[7:5] = 001 21 22 23 V Accuracy of POS Voltage VPOS 0x0E[5:0] = 010100, IOUT = 0mA 1 -- 1 % Accuracy of CPOUT VCPOUT 0x0F[5:0] = 010100, IOUT = 0mA 1.5 -- 1.5 % Drop-Out Voltage VDO VLCMOUT = VPOS = 5.2V, IOUT = 50mA -- 100 -- mV VMON Back Light LED % DSV Copyright © 2017 Richtek Technology Corporation. All rights reserved. DS4832A-00 January 2017 is a registered trademark of Richtek Technology Corporation. www.richtek.com 7 RT4832A Parameter Symbol Test Conditions Min Typ Max Unit DSV Switching Frequency f DSV 0.9 1 1.1 MHz Maximum Duty Cycle DMXDSV 90 93 -- % DSV N-MOSFET Ron RonNDSV 0.05 0.3 0.6  DSV P-MOSFET Ron RonPDSV 0x0F[5:0] = 010100 0.05 0.5 1  Charge Pump Equivalent Resistance Reqx1 VLCMOUT = 5.2V, IOUT = 50mA -- 2 --  VPOS Discharge Resistor RDP 0x0C[4] = 1 -- 70 --  VCPOUT Discharge Resistor RDN 0x0C[3] = 1 -- 20 --  LCMOUT Current Limit IOCPLCM 0x0E[5:0] = 010100 0.88 1.1 1.32 A POS Short Protection Voltage VSCPP -- 0.8 x VPOS -- V -- V CPOUT Short Protection Voltage VSCPN -- 0.25  0.8 x (VCP OUT) Logic Control (PWM, EN, ENP, ENM, SCL, SDA, TXMASK, STRB) Input Logic Low VIL -- -- 0.4 V Input Logic High VIH 1.4 -- -- V 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. JA is measured under natural convection (still air) at TA = 25°C with the component mounted on a high effective-thermal-conductivity four-layer test board on a JEDEC 51-7 thermal measurement standard. Note 3. Devices are ESD sensitive. Handling precaution recommended. Note 4. The device is not guaranteed to function outside its operating conditions. Copyright © 2017 Richtek Technology Corporation. All rights reserved. www.richtek.com 8 is a registered trademark of Richtek Technology Corporation. DS4832A-00 January 2017 RT4832A VLCM (2V/Div) VLCM VPOS VPOS (2V/Div) VCPOUT (2V/Div) IIN (500mA/Div) VCPOUT IIN Time (1ms/Div) DSV Power off with Discharge VLCM (2V/Div) VLCM VPOS VPOS (2V/Div) VCPOUT (2V/Div) VCPOUT IIN IIN (500mA/Div) Time (1ms/Div) DSV Ripple 0mA VCPOUT (20mV/Div) offset (-5V) IIN (50mA/Div) VIN = 3.7V, VLCM = 5.2V, VPOS = 5V, VCPOUT = -5V, IPOS_CPOUT = 0mA VIN = 3.7V, VLCM = 5.2V, VPOS = 5V, VCPOUT = -5V, IPOS_CPOUT = 0 to 5o to 0mA DSV Load Transient VPOS (20mV/Div) offset(5V) VPOS (20mV/Div) offset(5V) VCPOUT (20mV/Div) offset (-5V) Time (10ms/Div) Time (2ms/Div) DSV Accuracy_POS DSV Ripple 50mA Time (500s/Div) Copyright © 2017 Richtek Technology Corporation. All rights reserved. January 2017 VIN = 3.7V, 0x0C = 0x48, 0x0D = 0x18, 0x0E = 0x14, 0x0F = 0x14 0.8 0.6 Accuracy (%) VCPOUT (20mV/Div) offset (-5V) DS4832A-00 1.0 VIN = 3.7V, VLCM = 5.2V, VPOS = 5V, VCPOUT = -5V, IPOS_CPOUT = 50mA VPOS (20mV/Div) offset(5V) VIN = 3.7V, VLCM = 5.2V, VPOS = 5V, VCPOUT =- 5V, IPOS_CPOUT = 0mA, DSV_VPOS_disc enable, DSV_CPOUT_disc enable. DSV Power On VIN = 3.7V, VLCM = 5.2V, VPOS = 5V, VCPOUT = -5V, IPOS_CPOUT = 0mA, delay time = No constraint, POS slew rate=2.8mV/us, CPOUT slew rate = 2.9mV/us Typical Operating Characteristics 0.4 0.2 0.0 -0.2 2.5V 3V 3.5V 4V 4.5V -0.4 -0.6 -0.8 -1.0 0 10 20 30 40 DAC Code is a registered trademark of Richtek Technology Corporation. www.richtek.com 9 RT4832A BLED Accuracy Linearty DSV Accuracy_CPOUT 2 1.0 1 VIN = 3.7V, 0x0C = 0x48, 0x0D = 0x18, 0x0E = 0x14, 0x0F = 0x14 0.8 0 Accuracy (%) Accuracy (%) 0.6 0.4 0.2 0.0 -0.2 2.5V 3V 3.5V 4V 4.5V -0.4 -0.6 -0.8 -1 -2 -3 -4 -5 -6 VIN = 3.7V, 2P10S, LED Brightness code from 0 to 2048 -7 -8 0.005 -1.0 0 10 20 30 40 0.01 0.015 DAC Code BLED Matching Linearty 0.025 BLED ILED vs. Brightness Code 2.0 0.025 VIN = 3.7V, 2P10S, LED Brightness code from 0 to 2048 1.8 1.6 0.020 1.4 1.2 I LED (A) Matching (%) 0.02 I LED (A) 1.0 0.8 0.015 0.010 0.6 0.4 0.005 VIN = 3.7V, 2P10S, LED Brightness code from 0 to 2048, 0x02[4] = 1 0.2 0.0 0.005 0.000 0.01 0.015 0.02 0.025 0 256 768 1024 1280 1536 1792 2048 BLED Efficiency vs. Input Voltage BLED ILED vs. Brightness Code 90 0.025 VIN = 3.7V, 2P10S, LED Brightness code from 0 to 2048, 0x02[4] = 0 88 86 Efficiency (%) 0.020 I LED (A) 512 Brightness Code I LED (A) 0.015 0.010 1MHz 500kHz 84 82 80 78 76 74 0.005 VIN = 2.5V to 5.5V, 2P10S, 72 ILED = 25mA per string 70 0.000 0 256 512 768 1024 1280 1536 1792 2048 Brightness Code Copyright © 2017 Richtek Technology Corporation. All rights reserved. www.richtek.com 10 2.5 3 3.5 4 4.5 5 5.5 Input Voltage (V) is a registered trademark of Richtek Technology Corporation. DS4832A-00 January 2017 RT4832A VIN = 3.7V to 4.5V VIN (1V/Div) VIN = 3.7V, IFLED_flash = 1.5A, IFLED_strobe = 375mA, Strobe timeout =1 024ms, 0x09 = 0x1C, 0x0A Txmask BLED Line Transient STRB (5V/Div) TXMASK (5V/Div) ILED (20mA/Div) CS2 (1V/Div) IFLED (500mA/Div) CS1 (1V/Div) Time (1ms/Div) Copyright © 2017 Richtek Technology Corporation. All rights reserved. DS4832A-00 January 2017 Time (200ms/Div) is a registered trademark of Richtek Technology Corporation. www.richtek.com 11 RT4832A Register Map RT4832A IC slave address = 7’b 0010001. I2C interface supports fast mode (bit rate up to 400kb/s). Address Address Name BIT R/W Default (Reset Value) 0x01 Vendor Code 1:0 R 10 10 RICHTEK BLED OVP 7:5 R/W 001 [000] = 18V, [001] = 22V, [010] = 25V, [011] = 29V, [100] = 33V, [101 to 111] = 36V BLED Mapping Code 4 R/W 1 [0] = Exponential, [1] = Linear. BLED PWM Config. 3 R/W 0 [0] = Active High, [1] = Active Low. Reserved 2:0 R/W 000 BL SW Frequency 7 R/W 0 0x02 BL Ramp Rate 6:3 R/W 0011 Reserved 2:1 R/W 00 0x03 [0] = 500kHz, [1] = 1MHz [0000] = 0s, [0001] = 500s, [0010] = 750s, [0011] = 1ms, [0100] = 2ms, [0101] = 5ms, [0110] = 10ms, [0111] = 20ms, [1000] = 50ms, [1001] = 100ms, [1010] = 250ms, [1011] = 800ms, [1100] = 1s, [1101] = 2s, [1110] = 4s, [1111] = 8s 11th bit enable of bled brightness control [0] = 10 bit brightness control, reg0x40[1] is MSB, reg0x04[2] is ignore. [1] = 11 bit brightness control, reg0x40[2] is MSB. Bled11th 0 R/W 1 Reserved 7:3 R/W 00000 11th LSB 2 R/W 1 BLED Brightness MSB 1:0 R/W 11 1024 steps, MSB BLED Brightness LSB 7:0 R/W 11111111 1024 steps, LSB 0x04 0x05 Description FLED LED1/2 Torch Current 7:4 R/W 0011 FLED LED1/2 Strobe 3:0 Current R/W 1110 0x06 Copyright © 2017 Richtek Technology Corporation. All rights reserved. www.richtek.com 12 [0000] = 25mA, [0001] = 50mA, [0010] = 75mA, [0011] = 100mA, [0100] = 125mA, [0101] = 150mA, [0110] = 175mA, [0111] = 200mA, [1000] = 225mA, [1001] = 250mA, [1010] = 275mA, [1011] = 300mA, [1100] = 325mA, [1101] = 350mA, [1110 to 1111] = 375mA [0000] = 100mA, [0001] = 200mA, [0010] = 300mA, [0011] = 400mA, [0100] = 500mA, [0101] = 600mA, [0110] = 700mA, [0111] = 800mA, [1000] = 900mA, [1001] = 1000mA, [1010] = 1100mA, [1011] = 1200mA, [1100] = 1300mA, [1101] = 1400mA, [1110 to 1111] = 1500mA is a registered trademark of Richtek Technology Corporation. DS4832A-00 January 2017 RT4832A Address Name BIT R/W Default (Reset Value) FLED SW Freq. FL Current Limit 7:6 5 R/W R/W 00 1 FL Strobe Timeout 4:0 R/W 01111 dsv_periodic_mode 7 R/W 0 dsv_freq_pm 6 R/W 0 dsv_en_mode 5 R/W 0 Reserved 4 R/W 0 fla_ovp_sden 3 R/W 1 FLED VIN Monitor 2:0 R/W 100 Rst_sw_all 7 WC 0 [0] = turn on DSV only if EN = 1, [1] = turn on DSV only if (EN+ENP+ENM) = 1 -Flash OVP shutdown enable [0]=Report only, [1] = OVP Shutdown [000] = 2.5V, [001] = 2.6V, [010] = 2.7V, [011] = 2.8V, [100] = 2.9V, [101] = 3V, [110] = 3.1V, [111] = 3.2V Software reset [0] = Disable, [1] = Reset PWM Enable 6 R/W 0 [0] = PWM Ignored, [1] = PWM Enable dsv_ext_en 5 R/W 0 DSV external control enable [0] I2C control, [1] external pin control Strobe Enable 4 R/W 0 [0] = I2C Flash, [1] = Strobe Flash Tx Polarity 3 R/W 1 [0] = Active Low, [1] = Active High Tx Enable 2 R/W 0 [0] = Tx Ignored, [1] = Tx Enabled VIN Monitor Mode 1 R/W 1 [0] = Torch, [1] = Standby VIN Monitor En 0 R/W 0 [0] = Disable, [1] = VIN Monitor Enabled Rst_sw 7 WC 0 Fla_ch2_enb 6 R/W 0 BL OVP Disable 5 R/W 0 [0] = Report only, [1] = OVP Shutdown BLED1 En 4 R/W 0 [0] = Disable, [1] = Enable BLED2 En 3 R/W 0 [0] = Disable, [1] = Enable Torch/Flash 2 R/W 0 [0] = Torch, [1] = Flash Flash Enable Back Light Enable 1 0 R/W R/W 0 0 [0] = Off, [1] = Enable Flash [0] = Off, [1] = Enable Back Light Back Light OVP 7 R 0 [0] = Normal, [1] = Fault Flash OVP 6 R 0 [0] = Normal, [1] = Fault Flash Output Short 5 R 0 [0] = Normal, [1] = Fault VIN Monitor Tx Interrupt 4 3 R R 0 0 [0] = Normal, [1] = VIN Monitor Threshold Crossed [0] = Normal, [1] = Tx Event Occurs FLED1/2 Short 2 R 0 [0] = Normal, [1] = Fault Flash Timeout Thermal Shutdown 1 0 R R 0 0 [0] = Normal, [1] = Time out [0] = Normal, [1] = Fault Address 0x07 0x08 0x09 0x0A 0x0B Copyright © 2017 Richtek Technology Corporation. All rights reserved. DS4832A-00 January 2017 Description [00] = 4MHz, [01] = 2MHz [0] = 1.9A, [1] = 2.8A [00000] = 32ms ….. [01111] = 512ms [11111] = 1024ms, each step = 32ms DSV periodic mode [0] = always on if DSV is enable, [1] = DSV periodic mode [0] = 20Hz, [1] = 33Hz Software reset [0] = Disable, [1] = Reset excluding DSV [0] = FLASH channel2 enable, [1] = FLASH channel2 disable is a registered trademark of Richtek Technology Corporation. www.richtek.com 13 RT4832A Address 0x0C Address Name BIT R/W Default (Reset Value) pwr_sav 7 R/W 0 Power saving mode, [0] = Disable, [1] = Enable DSV_VPOS_en 6 R/W 0 DSV VPOS enable, [0] = Disable, [1] = Enable DSV_VPOS_gnd 5 R/W 1 DSV VPOS Ground, [0] = Floating, [1] = Grounding only function when VPOS is disable DSV_VPOS_disc 4 R/W 0 DSV VPOS discharge 20ms when shutdown, [0] = Disable, [1] = Enable DSV_VCPOUT_en 3 R/W 0 DSV_ VCPOUT _gnd 2 R/W 1 DSV_ VCPOUT _disc 1 R/W 0 DSV_Startup 0 R/W 0 DSV startup mode [0] = closed loop, waiting 80% [1] = open loop, go after soft-start dimming 00 DSV delay time between VPOS and VCPOUT [00] = No constraint [01] = 1ms [10] = 2ms [11] = 5ms DSV_delay 7:6 R/W 0x0D Vboost Voltage DSV_VPOS_slew 5:0 7:6 R/W R/W 101000 01 0x0E VPOS Voltage 5:0 DSV_VCPOUT_slew 7:6 R/W R/W 011110 5:0 R/W Copyright © 2017 Richtek Technology Corporation. All rights reserved. www.richtek.com 14 DSV VCPOUT enable, [0] = Disable, [1] = Enable DSV VCPOUT Ground, [0] = Floating, [1] = Grounding only function when VCPOUT is disable DSV VCPOUT discharge 20ms when shutdown, [0] = Disable, [1] = Enable [000000] = 4V ….. [010100] = 5V …… [101011] = 6.15V (0.05V per step) VPOS rising slew rate control [00] = 8.5mV/s [01] = 5.6mV/s, [10] = 4.6mV/s [11] = 2.8mV/s [000000] = 4V ….. [011110] = 5.5V …… [101000] = 6V (0.05V per step) 10 VCPOUT falling slew rate control [00] = 9.9mV/s [01] = 6.2mV/s, [10] = 4.9mV/s [11] = 2.9mV/s 011100 [000000] = 4V ….. [011100] = 5.4V …… [101000] = 6V (0.05V per step) 0x0F VCPOUT Voltage Description is a registered trademark of Richtek Technology Corporation. DS4832A-00 January 2017 RT4832A Address 0x10 Address Name BIT R/W Default (Reset Value) Reserved 7 R 0 [0] = Normal, [1] = Fault VPOS_SCP 6 R 0 [0] = Normal, [1] = Fault VCPOUT_SCP 5 R 0 [0] = Normal, [1] = Fault LCMOUT OCP 4 R 0 [0] = Normal, [1] = Fault VPOS OCP 3 R 0 [0] = Normal, [1] = Fault VCPOUT OCP 2 R 0 [0] = Normal, [1] = Fault Flash OCP 1 R 0 [0] = Normal, [1] = Fault Back Light OCP 0 R 0 [0] = Normal, [1] = Fault Copyright © 2017 Richtek Technology Corporation. All rights reserved. DS4832A-00 January 2017 Description is a registered trademark of Richtek Technology Corporation. www.richtek.com 15 RT4832A Application Information I2C I2C Write Control Slave ID S 0 0 1 0 0 R/W 0 1 0 A A Data Address P ACK from Slave ACK from Slave P I2C 0 Read Control 0 1 0 Slave ID R/W 0 0 A Write Data2 P ACK from Slave Slave ID S A Write Data1 ACK from Slave 1 0 A A Data Address ACK from Slave 0 0 1 0 ACK from Slave A Read Data1 ACK from Master R/W 0 0 1 1 A ACK from Slave A Read Data2 P NACK from Master |VCPOUT| should be higher than 150mV for good performance but the headroom voltage between DSV The RT4832A provides programmable LCMOUT, POS, CPOUT value. Table 1 contains the detail for DSV operation setting. The LCMOUT should be selected to provide enough headroom for good ripple and load transient performance. The headroom voltage between LCMOUT and the maximum value of VPOS and LCMOUT and |VCPOUT| should not be higher than 200mV to avoid the larger ripple at VCPOUT. The OCP level of POS is 250mA and CPOUT is 150mA typically. Table 1. DSV Operation Setting Channel Range Step Register Default Value Suggest Setting LCMOUT 4V to 6.15V 50mV/LSB 0x0D[5:0] 6V 5.7V VPOS 4V to 6V 50mV/LSB 0x0E[5:0] 5.5V 5.5V CPOUT 4V to 6V 50mV/LSB 0x0F[5:0] 5.4V 5.5V The DSV con be controlled either by pins or register bits. Table 2 is the DSV operation control table. Table 2. DSV Operation Control Table Dsv_ext_en DSV_vpos_en DSV_vneg_en ENM pin 0x09[5] 0x0C[6] 0x0C[3] X X X X EN pin ENP pin 0 X 1 X X 0 0 0 Standby 1 0 0 1 X X Standby 1 X X 0 1 0 VPOS enable 1 X X 0 0 1 VNEG enable 1 X X 0 1 1 VPOS & VNEG enable 1 1 0 1 X X VPOS enable 1 1 0 1 1 1 1 1 X X X X VNEG enable VPOS & VNEG enable Copyright © 2017 Richtek Technology Corporation. All rights reserved. www.richtek.com 16 Status Shutdown is a registered trademark of Richtek Technology Corporation. DS4832A-00 January 2017 RT4832A Discharge and Short to GND Function The RT4832A provides internal switch resister to discharge voltage of VPOS and CPOUT during the channel power off. Set the 0x0C[4] = 1 for VPOS discharge enable and 0x0C [1]=1 for CPOUT discharge enable. When the voltage discharge to GND, set the 0x0C[5] = 1 and 0x0C[2] = 1 will keep the output connect to GND. Power Saving Mode The RT4832A provides the power saving mode to bypass the input voltage to VPOS. Enable the 0x0C[7] = 1 to control the high side switch of boost converter and the LDO fully turn on to save the quiescent current and switching current. The POS is equal to Vin and CPOUT is equal to –Vin when power saving mode. Delay Time Control of POS & CPOUT The RT4832A provides the delay time control between POS and CPOUT power on and off. The bits of the 0x0D[7:6] is used to set the delay time. Table 3 and Figure 2 shows the delay time and the sequence for DSV power on and off. Table 3. DSV Delay Time Control Table 0x0D[7: 6] Delay time Power on 00 No constraint POS start ramp up when ENP = H or dsv_vpos_en = 1, CPOUT start ramp down when ENM = H or dsv_vcpout_en = 1. CPOUT start discharge when ENM = L or dsv_vcpout_en = 0, POS start discharge when ENP = L or dsv_vpos_en = 0. 1ms POS start ramp up when ENP = H or dsv_vpos_en = 1 CPOUT start ramp down after POS ramp up to target and delay 1ms even the ENM = H or dsv_vcpout_en = 1 CPOUT start discharge when ENM = L or dsv_vcpout_en = 0 POS start discharge after CPOUT discharge to GND and delay 1ms even the ENP = L or dsv_vpos_en = 0 2ms POS start ramp up when ENP = H or dsv_vpos_en = 1 CPOUT start ramp down after POS ramp up to target and delay 2ms even the ENM = H or dsv_vcpout_en = 1 CPOUT start discharge to GND when ENM = L or dsv_vcpout_en = 0 POS start discharge after CPOUT discharge to GND and delay 2ms even the ENP = L or dsv_vpos_en = 0 5ms POS start ramp up when ENP = H or dsv_vpos_en = 1 CPOUT start ramp down after POS ramp up to target and delay 5ms even the ENM = H or dsv_vcpout_en = 1 CPOUT start discharge when ENM = L or dsv_vcpout_en = 0 POS start discharge after CPOUT discharge to GND and delay 5ms even the ENP = L or dsv_vpos_en = 0 01 10 11 Periodic Mode The RT4832A supports the DSV periodic mode with the enable bit 0x08[7] and frequency select bit 0x08[6]. dsv_periodic_mode 0x08[7] 0 0 1 1 January 2017 In the periodic mode, the enable channel of the POS and CPOUT repeat on/off. The delay time, slew rate, discharge and GND connect follow the register setting. Table 4. Periodic Mode Control Table dsv_freq_pm ton (ms) 0x08[6] 0 X 1 X 0 2 1 1.6 Copyright © 2017 Richtek Technology Corporation. All rights reserved. DS4832A-00 Power off tperiod (ms) X X 50 30 is a registered trademark of Richtek Technology Corporation. www.richtek.com 17 RT4832A VIN Periodic mode ENP VBST VPOS ENM VCPOUT 0 0 tperiod tperiod 0 ton 0 ton ton ... 0 0 0 ... Figure 3. Periodic Mode Control Backlight LED The RT4832A provides brightness controllable backlight LED for maximum 2P10S application. The LED current be set via register and external PWM pin. Each channel can be control by enable bits (LED1 in register 0x0A [4] and LED2 in register 0x0A [3]). The ramp time from one brightness current to another current can be adjusted from 0ms to 8000ms in the register 0x03[6:3]. There are two different ways to map Back Light Enable 0x0A[0] BLED1 En 0x0A[4] the brightness code (or PWM duty cycle) to the LED current: linear and exponential mapping. The RT4832A LED serial number depends on the minimum voltage of the battery and the forward voltage(VF) of the LED. If the minimum voltage is 2.7V and the VF of the backlight LED is 3.2V, the maximum number of each string is 8. Table 5. BLED Operation Control Table PWM BLED2 En Enable PWM pin 0x0A[3] 0x09[6] Status 0 X X X X Standby 1 0 0 X X LED Bias enable 1 1 0 0 X ILED1 = BLED Brightness 1 0 1 0 X ILED2 = BLED Brightness 1 1 1 0 X ILED1 & ILED2 = BLED Brightness 1 1 0 1 Duty ILED1 =(BLED Brightness*PWM Duty) 1 0 1 1 Duty ILED1 =(BLED Brightness*PWM Duty) 1 1 1 1 Duty ILED1 = ILD2 = (BLED Brightness*PWM Duty) Copyright © 2017 Richtek Technology Corporation. All rights reserved. www.richtek.com 18 is a registered trademark of Richtek Technology Corporation. DS4832A-00 January 2017 RT4832A Brightness Control ILED = 0.0122mA*Brightness Code a. PWM Brightness Dimming In exponential mapped mode the LED current follows the relationship: Besides programmable built-in I2C backlight LED current control, the RT4832A features a built-in PWM dimming current control by setting register 0x09[6]=1, offering a linear current dimming by external clock source. In order to guarantee the PWM dimming resolution (7 bit at > 15kHz application), recommending dimming frequency have to be operated at range of 400Hz to 20kHz. 2 b. I C Brightness Dimming The RT4832A is built-in an I2C 10-bit or 11-bit resolution brightness control with maximum 25mA per string. When LED brightness is controlled from the I2C brightness registers (register 0x09[6]=0) , the 11-bit brightness data is default to controls the LED current in LED1 and LED2. The I2C brightness dimming is the concatenation of the two brightness registers (registers 0x04[2:0] and 0x05[7:0]). The LED current only changes when the MSBs are written, meaning that to do a full 11-bit current change via I2C, first the 3 MSBs are written and then the 8 LSBs are written. It can be selected as either linear or exponential. (register 0x02[4]). In linear mapped mode the LED current follows the ILED = 0.0183mA*(1.0035Brightness Code ) The 11-bit exponential mapping is small enough such that the transition from one code to the next in terms of LED brightness is not distinguishable to the eye. c. LED Brightness Current and PWM The LED brightness current is controlled with the register and the PWM Duty Cycle. LED current mapping can be selected as either linear or exponential, shows as the Figure 4. The LED current is approximated by the equation : With linear mapping the 10 bit code to current is approximates by the equation : ILED = 0.0244mA*Brightness Code*PWM Duty With linear mapping the 11 bit code to current is approximates by the equation : ILED = 0.0122mA*Brightness Code*PWM Duty With exponential mapping the 10 bit code to current is approximates by the equation : ILED = 0.0183mA*(1.0071Brightness Code*PWM Duty ) With exponential mapping the 11 bit code to current is approximates by the equation : ILED = 0.0183mA*(1.0035Brightness Code*PWM Duty ) relationship : 10 bit LED Current vs. Exponential Brightness Code 0.025 0.025 0.020 0.020 LED Current (mA) LED Current (mA) 10 bit LED Current vs. Linearty Brightness Code 0.015 0.010 0.015 0.010 0.005 0.005 0.000 0.000 0 256 512 768 Brightness Code (LSB) Copyright © 2017 Richtek Technology Corporation. All rights reserved. DS4832A-00 January 2017 1024 0 256 512 768 1024 Brightness Code (LSB) is a registered trademark of Richtek Technology Corporation. www.richtek.com 19 RT4832A 11 bit LED Current vs. Exponential Brightness Code 0.025 0.025 0.020 0.020 LED Current (mA) LED Current (mA) 11 bit LED Current vs. Linearty Brightness Code 0.015 0.010 0.015 0.010 0.005 0.005 0.000 0.000 0 256 512 768 1024 1280 1536 1792 2048 0 256 Brightness Code (LSB) 512 768 1024 1280 1536 1792 2048 Brightness Code (LSB) Figure 4. LED Current vs Brightness Code Ramp Rate There are 16 programmable ramp rates available in the RT4832A. These ramp rates are programmable as a time. Therefore, the ramp time from one current set-point to the next, depends on the register 0x03[6:3]. Over-Voltage Protection (Open LED, Open Circuit) The RT4832A provides an internal over voltage protection to limit its output voltage. The OVP function prevents the RT4832A from damaging while open LED or open circuit condition occurs. Once the open circuit condition is removed, and the RT4832A will return to normal operation. Over-Current Protection The RT4832A features a 1.2A OCP. The driver provides cycle-by-cycle current limit function to control the current on power switch. The boost switch turns off when the inductor current reaches this current threshold and it remains off until the beginning of the next switching cycle. This protects the RT4832A and external component under overload conditions. Flash LED The RT4832A FLED provides a current regulated output to drive high current white LEDs for camera flash applications. The output current provides up to 375mA for torch and 1.5A for strobe per channel white Copyright © 2017 Richtek Technology Corporation. All rights reserved. www.richtek.com 20 LEDs for camera flash applications. It adopts two channels to provide accurately regulated current flow through two separate white LEDs. The RT4832A FLED can be set in Flash or Torch mode by the register and the STRB pin. Figure 5 shows the RT4832A FLED operation and Table 6 contains the FLED operation control table. Flash Mode In Flash Mode, FLED provides 15 different current levels from 100mA to 1500mA in step of 100mA. The flash currents are adjusted via the register 0x06[3:0] for flash brightness. RT4832A provides 32 steps timeout from 32ms to 1024ms in step of 32ms for flash mode only. The Flash mode can be set via the register 0x0A[1] = 1 and 0x0A[2] = 1. Timeout To avoid the thermal increase from flash current, RT4832A provides 32 steps timeout from 32ms to 1024ms in step of 32ms for flash mode only. The timeout can be set via the register 0x07[4:0]. Once a flash event is completed, the Flash Timeout flag in register 0x0B bit [1] is set. This is a status only flag so the Flash Enable bit is not cleared. If a Flash event is activated via the STROBE pin and STROBE transitions low after the end of the programmed flash timeout, the Flash event is terminated at the programmed Flash is a registered trademark of Richtek Technology Corporation. DS4832A-00 January 2017 RT4832A Timeout and the Flash time out flag is set. VIN Monitor In Flash mode, to avoid the flash current to let VIN drop to UVLO, RT4832A provides VIN monitor function for the battery voltage detecting. If the battery voltage less than the VIN monitor value, FLED will be into Torch mode and output the torch current. This function can be enable via set register 0x09[0] = 1 and 0x08[2:0] is the Vin monitor value. The Register 0x0B [4] has the fault flag set when the input voltage crosses the VIN value. 0x08[2:0] 000 001 010 011 100 101 110 111 FLED VIN Monitor Level 2.5V 2.6V 2.7V 2.8V 2.9V (default) 3V 3.1V 3.2V Torch Mode The torch mode can be set via the register 0x0A[1] = 1 and 0x0A[2] = 0. Table 6. FLED Operation Control Table Flash Strobe Torch/ STRB Enable Enable Flash Status pin 0x0A[1] 0x09[4] 0x0A[2] 0 X X X Standby 1 1 0 X Standby 1 1 1 0 1 1 Rising edge 1 1 0 X 0 1 Falling edge X 1 Torch mode Flash mode Torch mode Flash mode Txmask The TXmask pin is designed to clamp the flash LED to torch current or no current that depend on the register setting when the PA transmit. This function can be enable by set the reg 0x09[2] = 1 and the reg 0x09[3] is used to define this pin active high or low. In Torch Mode, FLED provides 15 different current levels from 25mA to 375mA in step of 25mA. Torch current is activated by setting register 0x06 [7:4]. Once Torch Mode is enabled, the current sources will ramp up to the programmed torch current level by stepping. Copyright © 2017 Richtek Technology Corporation. All rights reserved. DS4832A-00 January 2017 is a registered trademark of Richtek Technology Corporation. www.richtek.com 21 RT4832A Torch Mode Strobe Enable 0 Vin Monitor 0 Torch/ Flash 0 STRB 0 Txmask 0 IFLED 0 Torch Current Torch Current Torch Current Torch Current Torch Current Flash Mode Strobe Enable 0 Vin Monitor 0 Torch/ Flash 0 STRB > Flash Timeout 0 Txmask 0 Flash Current Flash Current Flash Current IFLED Flash Current Flash Timeout 0 Torch Current Torch Current Torch Current Figure 5. Flash LED Operation Over-Voltage Protection (Open LED, Open Circuit) The RT4832A FLED provides an internal over voltage protection to limit its output voltage. The OVP function prevents the RT4832A from damaging while open LED or open circuit condition occurs. Once the open circuit condition is removed, and the RT4832A will return to normal operation. of the switching cycle. Switching resumes at the start of the next switching period. If the overcurrent condition persists, the device operates continuously in current limit. This prevents damage to the RT4832A and excessive current draw from the battery during output short-circuit conditions. When Flash occurs the current Limit event, the FLASH_OCP flag (register 0x10 bit [1]) is set. Over-Current Protection Over-Temperature Protection The RT4832A features two selectable flash inductor current limits that are programmable through the I2C compatible interface. When the inductor current limit is reached, the RT4832A terminates the charging phase Copyright © 2017 Richtek Technology Corporation. All rights reserved. www.richtek.com 22 The RT4832A provides an over-temperature protection to prevent the IC from overheating. When the junction temperature rises above 145C, the OTP function will is a registered trademark of Richtek Technology Corporation. DS4832A-00 January 2017 RT4832A protection threshold by 25C, the IC will enter normal operation again. Thermal Considerations The junction temperature should never exceed the absolute maximum junction temperature TJ(MAX), listed under Absolute Maximum Ratings, to avoid permanent damage to the device. The maximum allowable power dissipation depends on the thermal resistance of the IC package, the PCB layout, the rate of surrounding airflow, and the difference between the junction and ambient temperatures. The maximum power dissipation can be calculated using the following formula : PD(MAX) = (TJ(MAX) - TA) / JA where TJ(MAX) is the maximum junction temperature, TA is the ambient temperature, and JA is the junction-to-ambient thermal resistance. For continuous operation, the maximum operating junction temperature indicated under Recommended Operating Conditions is 125°C. The junction-to-ambient thermal resistance, JA, is highly package dependent. For a WL-CSP-30B 2.24x2.64 (BSC) package, the thermal resistance, JA, is 31.7°C/W on a standard JEDEC 51-7 high effective-thermal-conductivity four-layer test board. The maximum power dissipation at TA = 25°C can be calculated as below : 4.0 Maximum Power Dissipation (W)1 be triggered and then the LED driver will be shut down. The OTP hysteresis is 15C. Once the junction temperature reduces below the over temperature The maximum power dissipation depends on the operating ambient temperature for the fixed TJ(MAX) and the thermal resistance, JA. The derating curves in 3.2 2.8 2.4 2.0 1.6 1.2 0.8 0.4 0.0 0 25 50 75 100 125 Ambient Temperature (°C) Figure 6. Derating Curve of Maximum Power Dissipation Layout Considerations For high frequency switching power supplies, the PCB layout is important to get good regulation, high efficiency and stability. The following descriptions are the guidelines for better PCB layout.  For good regulation, place the power components as close to chip as possible. The traces should be wide and short enough especially for the high-current loop.  Minimize the size of the LX node and route on the top layer only.  Place the capacitor CIN as close to VIN pin as possible. PD(MAX) = (125°C - 25°C) / (31.7°C/W) = 3.15W for a WL-CSP-30B 2.24x2.64 (BSC) package. Four-Layer PCB 3.6  Place the CPOS, CCPOUT capacitor as close to the output pins as possible. Also place the charge pump flying capacitor close to the RT4832A.  Figure 6 allows the designer to see the effect of rising ambient temperature on the maximum power dissipation. Place the capacitor CFLED as close to FLEDOUT pin as possible. Connect the Flash LED cathode directly to the FLEDGND pin of the RT4832A.  Route the LED return with a dedicated path and keep the LED1 and LED2 path short and close to RT4832A for the good LED current performance. Copyright © 2017 Richtek Technology Corporation. All rights reserved. DS4832A-00 January 2017 is a registered trademark of Richtek Technology Corporation. www.richtek.com 23 RT4832A CIN ■ TOP Layer ■ Bottom Layer VIN ■ Bottom Layer GND VIN LLCM LBLED CLCM DBLED CFLY LCM OUT LCM SW LED GND LED SW ENM ENP EN LCM GND LED OUT C1 SDA Tx mask AGND LED1 LED2 CP GND SCL STRB PWM C2 Flash LED Flash OUT Flash SW VIN CP OUT Flash LED Flash OUT Flash SW Flash GND CBLED CPOS POS LED1 LED OUT CCPOUT LED2 FLED GND FLED OUT CFLED LFLED CIN2 VIN Figure 7. PCB Layout Guide Copyright © 2017 Richtek Technology Corporation. All rights reserved. www.richtek.com 24 is a registered trademark of Richtek Technology Corporation. DS4832A-00 January 2017 RT4832A Outline Dimension Dimensions In Millimeters Symbol Dimensions In Inches Min Max Min Max A 0.500 0.600 0.020 0.024 A1 0.170 0.230 0.007 0.009 b 0.240 0.300 0.009 0.012 D 2.590 2.690 0.102 0.106 D1 E 2.000 2.190 0.079 2.290 0.086 0.090 E1 1.600 0.063 e 0.400 0.016 30B WL-CSP 2.24x2.64 Package (BSC) Copyright © 2017 Richtek Technology Corporation. All rights reserved. DS4832A-00 January 2017 is a registered trademark of Richtek Technology Corporation. www.richtek.com 25 RT4832A Footprint Information Package Number of Pin Type Footprint Dimension (mm) e NSMD WL-CSP2.24*2.64-30(BSC) 30 SMD 0.400 A B 0.240 0.340 0.270 0.240 Tolerance ±0.025 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. Copyright © 2017 Richtek Technology Corporation. All rights reserved. www.richtek.com 26 is a registered trademark of Richtek Technology Corporation. DS4832A-00 January 2017