AS3649-ZWLT

AS3649 2500mA High Current LED Flash Driver 1 General Description 2 Key Features The AS3649 is an inductive high efficient DCDC step up converter with two current sources. The DCDC step up converter operates at a fixed frequency of 4MHz and includes soft startup to allow easy integration into noise sensitive RF systems. The two current sources can operate in flash / torch or video light modes. High efficiency 4MHz fixed frequency DCDC Boost converter The AS3649 includes flash timeout, overvoltage, overtemperature, undervoltage and LED short/open circuit protection functions. A TXMASK/TORCH function reduces the flash current in case of parallel operation to the RF power amplifier and avoids a system shutdown. Alternatively this pin can be used to directly operate the torch light directly. If the TXMask function is not used, it can be used as a hardware torch input (programmable). Automatic current adjustment for low battery voltage A hardware NTC pin can be used to measure the LED temperature with the ADC and to automatically reduce the LED current if a temperature threshold is exceeded. 2 The AS3649 is controlled by an I C interface and has a hardware reset pin ON. Setting ON=0 resets the AS3649. Interface input voltage levels are 1.8V compliant. The AS3649 is available in a space-saving WL-CSP package measuring only 2.06x2.02x0.6mm and operates over the -30ºC to +85ºC temperature range. with soft start allows small coils - Stable even in coil current limit LED current adjustable up to 2x1000mA(2x1250mA with current boost) or 2000mA and automatic load balancing for two LEDs PWM operation for lower output current for reliable light output of the LED; can run at 31.5kHz to avoid audible noise Protection functions: Automatic Flash Timeout timer to protect the LED(s) Overvoltage and undervoltage Protection Overtemperature Protection LED short/open circuit protection ADC to measure LED temperature NTC to automatically reduce the flash current if the LED temperature is too high (programmable level) 2 I C Interface with hardware reset pin Available in tiny WL-CSP Package, 16 balls 0.5mm pitch, 2.06x2.02x0.6mm package size 3 Applications Flash/Torch for mobile phones Figure 1. Typical Operating Circuit $%&'(    &'   ! )*+ ,+(     www.ams.com/AS3649     " "!  .+ (01$ $$$$$$$$%%% $$$$$$$$&%%%   AS3649 #"       !$/  .* ! 1.0-2 " &' #"!   * 1 - 39 AS3649 Datasheet - P i n A s s i g n m e n t s 4 Pin Assignments Figure 2. Pin Assignments (Top View) AS3649
  
 
                 "  "  !      #  !#$" !#$"   4.1 Pin Description Table 1. Pin Description for AS3649 1 Pin Number Pin Name A1 PGND2 Power ground; make a short connection between all GND balls A2 PGND1 Power ground; make a short connection between all GND balls A3 VIN A4 ON B1 SW2 DCDC converter switching node - make a short connection to SW1 / coil LDCDC B2 SW1 DCDC converter switching node - make a short connection to SW2 / coil LDCDC B3 NTC LED temperature sensor input (NTC) for LED overtemperature protection B4 TXMASK/TORCH Description Positive supply voltage input - connect to supply and make a short connection to input capacitor CVIN and to coil LDCDC Hardware reset input; an active low signal resets the registers of AS3649 and enters shutdown 2 (and I C lines SDA and SCL are in high-Z), active high allows to operate the device Function 1: Connect to RF power amplifier enable signal - reduces currents during flash to avoid a system shutdown due to parallel operation of the RF PA and the flash driver 2 Function 2: Operate torch current level without using the I C interface to operate the torch 2 without need to start a camera processor (if the I C is connected to the camera processor C1 VOUT2 DCDC converter output capacitor - make a short connection to CVOUT / VOUT1 C2 VOUT1 DCDC converter output capacitor - make a short connection to CVOUT / VOUT2 www.ams.com/AS3649 1.0-2 2 - 39 AS3649 Datasheet - P i n A s s i g n m e n t s Table 1. Pin Description for AS3649 1 Pin Number Pin Name Description C3 SCL serial clock input for I C interface C4 SDA serial data input/output for I C interface (needs external pullup resistor) D1 LED_OUT2 Flash LED current source D2 LED_OUT1 Flash LED current source D3 AGND Analog ground; make a short connection between all GND balls D4 STROBE Digital input with pulldown to control strobe time for flash function 2 2 1. Final pinout subject to change - now only used to count number of pins www.ams.com/AS3649 1.0-2 3 - 39 AS3649 Datasheet - A b s o l u t e M a x i m u m R a t i n g s 5 Absolute Maximum Ratings Stresses beyond those listed in Table 2 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 Electrical Characteristics on page 5 is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Table 2. Absolute Maximum Ratings Parameter Min Max Units VIN to GND -0.3 +7.0 V STROBE, TXMASK/TORCH, SCL, SDA, ON, NTC to GND -0.3 VIN + 0.3 V SW1/2, VOUT1/2, LED_OUT1/2 to GND -0.3 +7.0 V VOUT1/2 to SW1/2 -0.3 voltage between AGND, PGND1/2 pins 0.0 Input Pin Current without causing latchup -100 Comments max. +7V V Note: Diode between VOUT1/2 and SW1/2 0.0 V short connection required +100 +IIN mA Norm: EIA/JESD78 Continuous power dissipation 1470 mW PT at 70ºC Continuous power dissipation derating factor 20 mW/ºC PDERATE ESD HBM ±2000 V Norm: JEDEC JESD22-A114F ESD CDM ±500 V Norm: JEDEC JESD 22-C101E Continuous Power Dissipation (TA = +70ºC) 1 2 Electrostatic Discharge Temperature Ranges and Storage Conditions Junction to ambient thermal resistance 50 ºC/W For more information about thermal metrics, see application note AN01 Thermal Characteristics Junction Temperature +150 ºC Internally limited (overtemperature protection), max. 20000s 3 Storage Temperature Range -55 +125 ºC Humidity 5 85 % Non condensing +260 ºC according to IPC/JEDEC J-STD-020 Body Temperature during Soldering Moisture Sensitivity Level (MSL) MSL 1 Represents a max. floor life time of unlimited 1. Depending on actual PCB layout and PCB used measured on demoboard; for peak power dissipation during flashing see document 'AS3649 Thermal Measurements' 2. PDERATE derating factor changes the total continuous power dissipation (PT) if the ambient temperature is not 70ºC. Therefore for e.g. TAMB=85ºC calculate PT at 85ºC = PT - PDERATE * (85ºC - 70ºC) 3. Measured on AS3649 demoboard. www.ams.com/AS3649 1.0-2 4 - 39 AS3649 Datasheet - E l e c t r i c a l C h a r a c t e r i s t i c s 6 Electrical Characteristics VVIN = +2.7V to +4.4V, TAMB = -30ºC to +85ºC, unless otherwise specified. Typical values are at VVIN = +3.7V, TAMB = +25ºC, unless otherwise specified. Table 3. Electrical Characteristics Symbol Parameter Condition Min Typ Max Unit 3.7 4.4 V General Operating Conditions VVIN Supply Voltage Pin VIN 2.7 VVINREDUCED_ Supply Voltage AS3649 functionally working, but not all parameters fulfilled 2.5 2.7 4.4 5.5 ISHUTDOWN Shutdown Current TXMASK/TORCH=L, STROBE=L, ON=L, VVIN= CCh) www.ams.com/AS3649 1.0-2 22 - 39 AS3649 Datasheet - D e t a i l e d D e s c r i p t i o n Table 9. Current Set LED2 Register Current Set LED2 Register Addr: 2 Bit Bit Name This register defines design versions Default Access Description Define the current on pin LED_OUT2; torch mode uses bits 5:0 of this current setting (max. 1/4 of full current setting) indicator or low current pwm mode uses only 5:0 of this current setting (max. 1/4 of full current setting) Note: Always keep led_current1 >= led_current2 led_current2 7:0 9Ch R/W 0h 0mA 1h 7.8mA 2h 11.7mA ... ... 3Fh 250mA (maximum current for torch light mode, indicator or low current pwm mode, mode_setting=01 or 10) ... ... 7Fh 500mA ... ... 9Ch 613.3mA - default setting ... ... FEh 996mA (1245mA if current_boost=1) FFh 1000mA (1250mA if current_boost=1) 1 1 1. Only use current_boost=1 for currents > 1000mA(code >= CCh) Table 10. TXMask Register TXMask Register Addr: 3 Bit Bit Name This register defines the TXMask settings and coil peak current Default Access Description Defines operating mode for input pin TXMASK/TORCH 1:0 txmask_torch_mode 00 00 pin has no effect 01 txmask-mode; during flash if TXMASK/TORCH=1, the LED current is set to flash_txmask_current - (see TXMASK on page 15) 10 external torch mode: if TXMASK/TORCH=1 and mode_setting=00, the AS3649is set into external torch mode 1 (LED current is defined by the 6LSB bits of led_current1 and led_current2) 11 don’t use R/W Defines the maximum coil current (parameter ILIMIT) 3:2 www.ams.com/AS3649 coil_peak 10 R/W 00 ILIMIT = 2.5A 01 ILIMIT = 2.9A 10 ILIMIT = 3.3A 11 ILIMIT = 3.7A 1.0-2 23 - 39 AS3649 Datasheet - D e t a i l e d D e s c r i p t i o n Table 10. TXMask Register (Continued) TXMask Register Addr: 3 Bit This register defines the TXMask settings and coil peak current Bit Name Default Access Description Define the current on pin LED_OUT1 and LED_OUT2 (each current source) in flash mode if txmask_torch_mode=01 and TXMASK/ TORCH=1 7:4 flash_txmask_current 2 6h R/W 0h 0mA 1h 31mA (39mA if current_boost=1) 2h 63mA (78mA if current_boost=1) 3h 94mA (118mA if current_boost=1) 4h 125mA (157mA if current_boost=1) 5h 157mA (196mA if current_boost=1) 6h 188mA (235mA if current_boost=1) - default 7h 220mA (275mA if current_boost=1) 8h 251mA (314mA if current_boost=1) 9h 282mA (353mA if current_boost=1) Ah 314mA (392mA if current_boost=1) Bh 345mA (431mA if current_boost=1) Ch 376mA (471mA if current_boost=1) Dh 408mA (510mA if current_boost=1) Eh 439mA (549mA if current_boost=1) Fh 471mA (588mA if current_boost=1) 1. The MSB bit of this register not used to protect the LED; therefore the maximum current = 1/4 the maximum flash current 2. If current_boost=1, the LED current is increased by 25%. Table 11. Low Voltage / NTC Register Low Voltage / NTC Register Addr: 4 Bit Bit Name This register defines the operating mode with low battery voltages Default Access Description Voltage level on VIN where current reduction triggers during operation (see Current Reduction by VIN Measurements in Flash Mode and Diagnostic Pulse on page 15) - only in flash mode; if VIN drops below this voltage during current ramp up, the current ramp up is stopped; during operation the current is decreased until the voltage on VIN rises above this threshold - status_uvlo is set 2:0 www.ams.com/AS3649 vin_low_v 4h R/W 0h function is disabled 1h 3.0V 2h 3.07V 3h 3.14V 4h 3.22V - default 5h 3.3V 6h 3.38V 7h 3.47V 1.0-2 24 - 39 AS3649 Datasheet - D e t a i l e d D e s c r i p t i o n Table 11. Low Voltage / NTC Register (Continued) Low Voltage / NTC Register Addr: 4 Bit Bit Name This register defines the operating mode with low battery voltages Default Access Description Enable overtemperature protection on pin NTC (internal comparator comparing NTC to VNTC_TH) 3 ntc_on 0 R/W 0 disabled 1 enabled Current through the NTC (INTC); it is enabled once the LED current source (LED_OUT1/2) is operating and ntc_on=1 or the ADC measures the LED temperature (see NTC - Flash LED Overtemperature Protection on page 14) 7:4 www.ams.com/AS3649 ntc_current 8h R/W 0h off; can be used to use an external current to bias the NTC 1h 40µA 2h 80µA 3h 120µA 4h 160µA 5h 200µA 6h 240µA 7h 280µA 8h 320µA - default 9h 360µA Ah 400µA Bh 440µA Ch 480µA Dh 520µA Eh 560µA Fh 600µA 1.0-2 25 - 39 AS3649 Datasheet - D e t a i l e d D e s c r i p t i o n Table 12. Flash Timer Register Flash Timer Register Addr: 5 Bit This register identifies the flash timer and timeout settings Bit Name Default Access Description Define the duration of the flash timer and timeout timer 5:0 flash_timeout 1 26h R/W 00h … 4ms 01h … 8ms 02h … 12ms 03h … 16ms 04h … 20ms 05h … 24ms 06h … 28ms 07h … 32ms 08h … 36ms 09h … 40ms 0Ah … 44ms 0Bh … 48ms 0Ch … 52ms 0Dh … 56ms 0Eh … 60ms 0Fh … 64ms 10h … 68ms 11h … 72ms 12h … 76ms 13h … 80ms 14h … 84ms 15h … 88ms 2Bh … 484ms 2Ch … 516ms 2Dh … 548ms 2Eh … 580ms 2Fh … 612ms 30h … 644ms 31h … 676ms 32h … 708ms 33h … 740ms 34h … 772ms 35h … 804ms 36h … 836ms 37h … 868ms 38h … 900ms 39h … 932ms 3Ah … 964ms 3Bh … 996ms 3Ch … 1028ms 3Dh … 1060ms 3Eh … 1092ms 3Fh … 1124ms 16h … 92ms 17h … 96ms 18h … 100ms 19h … 104ms 1Ah … 108ms 1Bh … 112ms 1Ch … 116ms 1Dh … 120ms 1Eh … 124ms 1Fh … 128ms 20h … 132ms 21h … 164ms 22h … 196ms 23h … 228ms 24h … 260ms 25h … 292ms 26h … 324ms 27h … 356ms 28h … 388ms 29h … 420ms 2Ah … 452ms 1. Internal calculation for codes above 20h: flash timeout [ms] = (flash_timeout-32) * 32 + 132 [ms] Table 13. Control Register Control Register Addr: 6 Bit Bit Name This register identifies the operating mode and includes an all on/off bit Default Access Description Define the AS3649 operating mode - see Table 5, “Operating Mode and Current Settings,” on page 14 standby/shutdown or external torch mode if txmask_torch_mode (page 23)=10 00 indicator mode (or low current mode using PWM) 01 1:0 mode_setting 00 R/W 1 LED current is defined by the 6LSB bits of led_current1 and led_current2 pwm modulated defined by register inct_pwm (31.5kHz: 1/16...4/16, 7.9kHz: 1/64...3/64) torch light mode: 10 2 LED current is defined by the 6LSB bits of led_current1 and led_current2 flash mode: LED current is defined by led_current1 and led_current2 (mode_setting is automatically cleared after a flash pulse) 11 www.ams.com/AS3649 1.0-2 26 - 39 AS3649 Datasheet - D e t a i l e d D e s c r i p t i o n Table 13. Control Register (Continued) Control Register Addr: 6 Bit Bit Name This register identifies the operating mode and includes an all on/off bit Default Access Description Increase min. on time of DCDC converter - use for diagnostic pulse, if freq_switch_on=1. If this register is not 00 and freq_switch_on=1, the DCDC converter will use 4MHz operation forced PWM mode or pass-through mode but will not switch to 1MHz operation 3:2 min_on_increase 00 R/W 00 100% - default min. on time 01 108% 10 131% 11 157% Force DCDC operation even in pass-through mode - use for diagnostic pulse, if freq_switch_on=1 4 force_dcdc_on 0 R/W 0 DCDC is only enabled when needed; default 1 DCDC is always enabled even when pass-though mode could be used Increase voltage compliance of current source for diagnostic pulses see Short Diagnostic Pulse on page 16 vcompl_adj 7:5 000b R/W 000 default - 0mV 001 14mV (26mV if current_boost=1) 010 29mV (51mV if current_boost=1) 011 43mV (77mV if current_boost=1) 100 57mV (103mV if current_boost=1) 101 71mV (129mV if current_boost=1) 110 85mV (154mV if current_boost=1) 111 100mV (180mV if current_boost=1) 1. The two MSB bits of this register are not used to protect the LED; therefore the maximum indicator (or low current mode using PWM) light current = 1/4 the maximum flash current multiplied by the duty cycle defined by inct_pwm 2. The two MSB bits of this register not used to protect the LED; therefore the maximum torch light current = 1/4 the maximum flash current Table 14. Strobe Signalling / ADC Register Strobe Signalling / ADC Register Addr: 7 Bit Bit Name This register defines the flash current reducing and mode for STROBE Default Access Description Select ADC channel for conversion 3:0 www.ams.com/AS3649 adc_channel 000b R/W 000 NTC 001 TJUNC 010 VIN 1.0-2 27 - 39 AS3649 Datasheet - D e t a i l e d D e s c r i p t i o n Table 14. Strobe Signalling / ADC Register (Continued) Strobe Signalling / ADC Register Addr: 7 Bit Bit Name This register defines the flash current reducing and mode for STROBE Default Access Description Start ADC conversion adc_convert 4 0 R/W 0 ADC conversion finished 1 Start ADC conversion - once finished the register bit is automatically reset and the result is stored in adc_result Allow pulseskip operation of DCDC - see Table 4 on page 12 5 dcdc_skip_enable 1 R/W 0 Disabled - force 4MHz (1MHz) operation 1 Enabled - can use pulseskip 1 Defines if the STROBE input is edge or level sensitive; see also bit strobe_on (page 28) strobe_type 6 1 R/W 0 STROBE input is edge sensitive 1 STROBE input is level sensitive Enables the STROBE input strobe_on 7 1 R/W 0 STROBE input disabled 1 STROBE input enabled in flash mode 1. Exception depending on freq_switch_on (see page 29) - see Table 4 on page 12 Table 15. Fault Register Fault Register Addr: 8 Bit 0 1 2 3 Bit Name status_uvlo reserved fault_ntc fault_txmask This register identifies all the different fault conditions and provide information about the LED detection Default 0 0 0 0 Access R/sC 1 Description an undervoltage event has happened - see Current Reduction by VIN Measurements in Flash Mode and Diagnostic Pulse on page 15 0 No 1 Yes R R/sC R/sC reserved - don’t use 1 1 LED overtemperature detection hit - see NTC - Flash LED Overtemperature Protection on page 14 0 No 1 Yes TXMASK/TORCH event triggered during flash - see TXMASK event occurred on page 13 0 No 1 Yes see Flash Timeout on page 14 4 www.ams.com/AS3649 fault_timeout 0 R/sC 1 0 No fault 1 Flash timeout exceeded 1.0-2 28 - 39 AS3649 Datasheet - D e t a i l e d D e s c r i p t i o n Table 15. Fault Register (Continued) Fault Register Addr: 8 Bit This register identifies all the different fault conditions and provide information about the LED detection Bit Name Default Access Description see Overtemperature Protection on page 13 5 fault_overtemp 0 R/sC 1 0 No fault 1 Junction temperature limit has been exceeded see Short Circuit Protection on page 13 6 fault_led_short 0 R/sC 1 0 No fault 1 A shorted LED is detected (pin LED_OUT1/2) see Overvoltage Protection on page 13 fault_ovp 7 0 R/sC 1 0 No fault 1 An overvoltage condition is detected (pin VOUT) 1. R/sC = Read, self clear; after readout the register is automatically cleared Table 16. PWM and Indicator Register PWM and Indicator Register Addr: 9 Bit This register defines the PWM mode (e.g. for indicator) and 4/1MHz mode switching Bit Name Default Access Description Define the AS3649 PWM with 31.5kHz or 7.9kHz operation for indicator or low current mode (mode_setting=01) 1 2:0 inct_pwm 00 R/W 000 1/16 duty cycle / 31.5kHz 001 2/16 duty cycle / 31.5kHz 010 3/16 duty cycle / 31.5kHz 011 4/16 duty cycle / 31.5kHz 100 1/64 duty cycle / 7.9kHz; needs const_v_mode=1 (additional quiescent current) 101 2/64 duty cycle / 7.9kHz; needs const_v_mode=1 (additional quiescent current) 110 3/64 duty cycle / 7.9kHz; needs const_v_mode=1 (additional quiescent current) 111 (4/64 duty cycle / 7.9kHz) don’t use; use 000 setting instead Exact frequency switching between 4MHz/1MHz for operation close to maximum pulsewidth - see Table 4 on page 12 3 freq_switch_on www.ams.com/AS3649 0 R/W 0 Pulseskip operation is allowed depending on dcdc_skip_enable (see page 28) 1 if led_current1>=40h or led_current2>=40h and current_boost=0, the DCDC is running at 4MHz or 1MHz and pulseskip is disabled results in improved noise performance 1.0-2 29 - 39 AS3649 Datasheet - D e t a i l e d D e s c r i p t i o n Table 16. PWM and Indicator Register (Continued) PWM and Indicator Register Addr: 9 Bit 4 This register defines the PWM mode (e.g. for indicator) and 4/1MHz mode switching Bit Name Default load_balance_on 0 Access R/W Description Balance the current sources (up to +/-15% of set current) to improve application efficiency for unmatched LED forward voltages - see Load Balancing on page 17 0 disabled 1 enabled Enables Constant output voltage mode 5 const_v_mode 0 0 Normal operation defined by mode_setting 1 5V constant voltage mode on VOUT1/2; LED current can be controlled by registers mode_setting, led_current1 and led_current2 as in normal operating mode, but the ramping up/down of the current sources is disabled (instantaneous on/off of the LED current) R/W 1. Using 31.5kHz modulation avoids audible noise on the output capacitor CVOUT Table 17. ADC Result Register ADC Result Register Addr: Ah This register reports the actual set LED current Bit Bit Name Default Access Description 7:0 adc_result NA R Result of ADC conversion for channel adc_channel Table 18. ADC Result LSBs Register ADC Result LSBs Register Addr: Bh This register reports the actual set LED current Bit Bit Name Default Access Description 1:0 adc_result_lsbs NA R Result of ADC conversion for channel adc_channel Table 19. Minimum LED Current Register Minimum LED Current Register Addr: Eh Bit 7:0 This register reports the minimum LED current from the last operation cycle Bit Name led_current_min Default 123 00h Access Description R see Current Reduction by VIN Measurements in Flash Mode and Diagnostic Pulse (see page 15) and Figure 20 on page 16 1. Only the current through LED_OUT1 is reported. 2. As the internal change of this register is asynchronous to the readout, it is recommended to readout the register after the flash pulse. The register will store the minimum current through the LED after e.g. a previous flash. This current can be used for a subsequent flash pulse for a safe operating range. 3. This register is only set if an actual current reduction happens (status_uvlo (see page 28)=1) otherwise led_current_min=0. www.ams.com/AS3649 1.0-2 30 - 39 AS3649 Datasheet - D e t a i l e d D e s c r i p t i o n Table 20. Actual LED Current Register Actual LED Current Register Addr: Fh Bit 7:0 This register reports the actual set LED current Bit Name led_current_actual 12 Default Access Description 00h R Actual set current through the current source (including all current reductions as described in Flash Current Reductions (see page 15) including LED current ramp up/down) 1. Only the current through LED_OUT1 is reported. 2. As the internal change of this register is asynchronous to the readout, it is recommended to readout the register twice and compare the results. Table 21. Unlock Register Register Unlock Register Register Addr: 80h Protection for register Current Boost Bit Bit Name Default Access Description 7:0 unlock NA W Write 55h into this register to enable access to register 81h Table 22. Current Boost Register Current Boost Register Addr: 81h Bit Increase output current by 25% Bit Name Default Access Description Boost all LED currents by 25% 0 current_boost 1 0 R/W 0 all LED current are as described in the tables 1 all LED current are increased by 25% 2 1. Write 55h into register unlock (0x80) to enable access to this register (unlocking is only valid for the next I C access) - required on any write access to this register www.ams.com/AS3649 1.0-2 31 - 39 AS3649 Datasheet - D e t a i l e d D e s c r i p t i o n 8.10 Register Map Table 23. Register Map Register Definition 1 Addr Default Name Content b7 b6 b5 b4 b3 ChipID 0 Cxh Current Set LED1 1 9Ch led_current1 Current Set LED2 2 9Ch led_current2 TXMask 3 68h flash_txmask_current Low Voltage / NTC 4 84h ntc_current Flash Timer 5 26h Control 6 00h Strobe Signalling / ADC 7 E0h dcdc_skip adc_conv strobe_on strobe_ty pe _enable ert Fault 8 00h fault_over fault_time fault_txm fault_ovp fault_led_ short temp out ask PWM and Indicator 9 00h const_v_ load_bala freq_switc mode nce_on h_on ADC Result Ah NA ADC Result LSBs Bh NA Minimum LED Current Eh 00h led_current_min Actual LED Current Fh 00h led_current_actual Unlock Register 80h 00h unlock Current Boost 81h 00h b2 fixed_id b1 b0 version coil_peak txmask_torch_mode ntc_on vin_low_v flash_timeout force_dcd c_on vcompl_adj min_on_increase mode_setting adc_channel fault_ntc reserved status_uvl o inct_pwm adc_result adc_result_lsbs current_b oost 1. Always write’0’ to undefined register bits www.ams.com/AS3649 1.0-2 32 - 39 AS3649 Datasheet - A p p l i c a t i o n I n f o r m a t i o n 9 Application Information 9.1 External Components 9.1.1 Input Capacitor CVIN Low ESR input capacitors reduce input switching noise and reduce the peak current drawn from the battery. Ceramic capacitors are required for input decoupling and should be located as close to the device as is practical. Table 24. Recommended Input Capacitor Part Number C TC Code Rated Voltage Size Manufacturer GRM188R60J106ME47 10µ >3µF@4.5V >2µF@5.25V X5R 6V3 0603 Murata www.murata.com LMK107BBJ106MA 10µ >3µF@4.5V X5R 6V3 0603 Taiyo Yuden www.t-yuden.com If a different input capacitor is chosen, ensure similar ESR value and at least 3µF capacitance at the maximum input supply voltage. Larger capacitor values (C) may be used without limitations. Add a smaller capacitor in parallel to the input pin VIN (e.g. Murata GRM155R61C104, >50nF @ 3V, 0402 size). 9.1.2 Output Capacitor CVOUT Low ESR capacitors should be used to minimize VOUT ripple. Multi-layer ceramic capacitors are recommended since they have extremely low ESR and are available in small footprints. The capacitor should be located as close to the device as is practical. X5R dielectric material is recommended due to their ability to maintain capacitance over wide voltage and temperature range. Table 25. Recommended Output Capacitor Part Number C TC Code Rated Voltage Size GRM219R61A106ME47 10µF +/-10% >4.2µF@5V X5R 10V 0805 (2.0x1.25x0.85mm max 1mm height) 22µF >4.2µF@4.5V X5R 6.3V 0805 (2.0x1.25x1.25mm max. 1.4mm height) 10µF +/-20% >4.2µF@4V X5R 6.3V 0603 (1.6x0.8x0.85mm max. 0.95mm height) GRM21BR60J226M 1 GRM188R60J106ME84 2 Manufacturer Murata www.murata.com 1. Use only for VLED < 4.1V 2. Use only for VLED < 3.75V If a different output capacitor is chosen, ensure similar ESR values and at least 4.2µF capacitance at 5V output voltage. www.ams.com/AS3649 1.0-2 33 - 39 AS3649 Datasheet - A p p l i c a t i o n I n f o r m a t i o n 9.1.3 Inductor LDCDC The fast switching frequency (4MHz) of the AS3649 allows for the use of small SMDs for the external inductor. The saturation current 15 ISATURATION should be chosen to be above the maximum value of ILIMIT . The inductor should have very low DC resistance (DCR) to reduce 2 the I R power losses - high DCR values will reduce efficiency. Table 26. Recommended Inductor Part Number L DCR ISATURATION Size Manufacturer LQM32PN1R0MG0 1.0µH >0.6µH @ 3.0A 60m 3.0A 3.2x2.5x0.9mm max 1.0mm height Murata www.murata.com SPM4012T-1R0M 1.0µH +/-20% 38m 4.57A 4.4x4.1x1.2 mm height is max 2 3.2x3x1.2 mm height is max 4 3.2x2.5mm max 1.0mm height 4 3.2x2.5x0.9mm max 1.0mm height 3 2.4x2.4x1.2mm (height is max.) 4 2.5x2.0x1.2mm height is max 1 SPM3012T-1R0M 1.0µH +/-20% 57m +/-10% 3.4A CIG32W1R0MNE 1.0µH >0.7µH @ 2.7A >0.6µH @ 3.0A 60m +/-25% 3.0A CKP3225N1R0M 1.0µH >0.6µH @ 3.0A 0.6µH @ 2.5A 77m 2.5A MAMK2520T1R0M 1.0µH >0.6µH @ 2.75A 45m 3.1A TDK www.tdk.com Samsung Electro-Mechancs www.sem.samsung.co.kr Taiyo Yuden www.t-yuden.com 1. Flash pattern: 200ms/3A, 200ms pause, 200ms/3A, 2s then repeat again (no limit on the number of total cycles) Alternative pattern with 1000ms/1.6A, 200ms pause, 200ms/3A, 200ms pause, 200ms/3A, 2s then repeat again. (no limit on the number of total cycles). Use only up to coil_peak=2.9A setting 2. Inductance changes by -30%, use only up to coil_peak=3.3A setting 3. Use only for coil_peak=2.5A setting. 4. Use only up to coil_peak=2.9A setting. If a different inductor is chosen, ensure similar DCR values and at least0.6µH inductance at ILIMIT. 9.1.4 Thermistor (NTC) The NTC is used to protect the LED against overheating (hardware protection inside the AS3649, which works without any software - see NTC Flash LED Overtemperature Protection on page 14). The thermistor has to be thermally coupled to the LED (and therefore as close as possible to the LED) and it shall not share the same ground connection as the LED return ground (if they share the same ground connection the high current through the LED will offset the measurement of the NTC). Table 27. Recommended Thermistors Part Number Resistance @ 25ºC B-constant 25/50ºC NCP03WL224E05RL 220k +/-3% 4485K +/-1% NCP03WL104E05RL 100k +/-3% 4485K +/-1% NCP15WF104F03RC 100k NCP15WL683J03RC 68k Size Manufacturer 0201 Murata www.murata.com 0402 It is recommended to use 220k resistance for a detection threshold of 125ºC, 100k for 110ºC and 68k for 80ºC LED temperature detection threshold. 15.Can be adjusted in I2C mode with register coil_peak (see page 23) www.ams.com/AS3649 1.0-2 34 - 39 AS3649 Datasheet - A p p l i c a t i o n I n f o r m a t i o n 9.2 PCB Layout Guideline The high speed operation requires proper layout for optimum performance. Route the power traces first and try to minimize the area and wire length of the two high frequency/high current loops: Loop1: CVIN/CVIN2 - LDCDC - pin SW1/2 - pin GND - CVIN/CVIN2 Loop2: CVIN/CVIN2 - LDCDC - pin SW1/2 - pin VOUT1/2 - CVOUT - pin GND - CVIN/CVIN2 At the pin GND a single via (or more vias, which are closely combined) connects to the common ground plane. This via(s) will isolate the DCDC high frequency currents from the common ground (as most high frequency current will flow between Loop1 and Loop2 and will not pass the ground plane) - see the ‘island’ in Figure 31. Figure 31. Layout Recommendation "-.  ** +,-./,-01         *

'$ )   )$ )       "-.. 
 )         !"# *4 ,-"
, * /2+1 $   5* 234
234,     !"# $ % &$ $$  )                Note: If component placement rules allow, move all components close to the AS3649 to reduce the area and length of Loop1 and Loop2. It is recommended to use the main ground plane for the LED ground connections (improved thermal performance of the LEDs) - it is recommend to use a separate ground line as shown Figure 31 for the ground connection of the NTC (this avoids errors for the temperature measurement of the LEDs due to the high LED current in the main ground plane). Keep the LED path (from pin LED_OUT1/2 to the LED and the ground return path) below 10cm (represents an inductance of less than 100nH). An additional 100nF (e.g. Murata GRM155R61C104, >50nF @ 3V, 0402 size) capacitor CVIN2 in parallel to CVIN is recommended to filter high frequency noise for the power supply of AS3649. This capacitor should be as close as possible to the AGND/VIN pins of AS3649. www.ams.com/AS3649 1.0-2 35 - 39 AS3649 Datasheet - A p p l i c a t i o n I n f o r m a t i o n 9.3 5V Operating Mode The AS3649 can be used to power a 5V system (e.g. audio amplifier). The operating mode is selected by setting register bit const_v_mode (page 30)=1. Note: There is always a diode between VIN and VOUT1/2 due to the internal circuit. Therefore VOUT1/2 cannot be completely switched off Figure 32. 5V Operating Mode     AS3649               www.ams.com/AS3649 1.0-2 36 - 39 AS3649 Datasheet - P a c k a g e D r a w i n g s a n d M a r k i n g s 10 Package Drawings and Markings Figure 33. WL-CSP16 Marking   
                                Note: Line 1: Line 2: Line 3: ams AG logo AS3649 Encoded Datecode (4 characters) Figure 34. WL-CSP16 Package Dimensions    ! "#$ %#&
   
  * ''
'
   $
$' $* $* $' $
$  
' * * ' 
 ( (
(' (* (* (' (
( ) )
)' )* )* )' )
)    '
+    




  $



 ' The coplanarity of the balls is 40µm. www.ams.com/AS3649 1.0-2 37 - 39 AS3649 Datasheet - O r d e r i n g I n f o r m a t i o n 11 Ordering Information The devices are available as the standard products shown in Table 28. Table 28. Ordering Information Ordering Code AS3649-ZWLT Description Delivery Form Package Tape & Reel 16-pin WL-CSP (2.06x2.02x0.6mm) 0.5mm pitch RoHS compliant / Pb-Free / Green 2500mA High Current LED Flash Driver Z Temperature Range: -30ºC - 85ºC WL Package: Wafer Level Chip Scale Package (WL-CSP) 2.06x2.02x0.6mm T Delivery Form: Tape & Reel Note: All products are RoHS compliant and ams green. Buy our products or get free samples online at www.ams.com/ICdirect Technical Support is available at www.ams.com/Technical-Support For further information and requests, email us at sales@ams.com (or) find your local distributor at www.ams.com/distributor www.ams.com/AS3649 1.0-2 38 - 39 AS3649 Datasheet - O r d e r i n g I n f o r m a t i o n Copyrights Copyright © 1997-2013, ams AG, Tobelbaderstrasse 30, 8141 Unterpremstaetten, Austria-Europe. Trademarks Registered ®. All rights reserved. The material herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. All products and companies mentioned are trademarks or registered trademarks of their respective companies. Disclaimer Devices sold by ams AG are covered by the warranty and patent indemnification provisions appearing in its Term of Sale. ams AG makes no warranty, express, statutory, implied, or by description regarding the information set forth herein or regarding the freedom of the described devices from patent infringement. ams AG reserves the right to change specifications and prices at any time and without notice. Therefore, prior to designing this product into a system, it is necessary to check with ams AG for current information. This product is intended for use in normal commercial applications. Applications requiring extended temperature range, unusual environmental requirements, or high reliability applications, such as military, medical life-support or life-sustaining equipment are specifically not recommended without additional processing by ams AG for each application. For shipments of less than 100 parts the manufacturing flow might show deviations from the standard production flow, such as test flow or test location. The information furnished here by ams AG is believed to be correct and accurate. However, ams AG shall not be liable to recipient or any third party for any damages, including but not limited to personal injury, property damage, loss of profits, loss of use, interruption of business or indirect, special, incidental or consequential damages, of any kind, in connection with or arising out of the furnishing, performance or use of the technical data herein. No obligation or liability to recipient or any third party shall arise or flow out of ams AG rendering of technical or other services. Contact Information Headquarters ams AG Tobelbaderstrasse 30 A-8141 Unterpremstaetten, Austria Tel Fax : +43 (0) 3136 500 0 : +43 (0) 3136 525 01 For Sales Offices, Distributors and Representatives, please visit: http://www.ams.com/contact www.ams.com/AS3649 1.0-2 39 - 39