austriamicrosystems AG is now ams AG The technical content of this austriamicrosystems datasheet is still valid. Contact information: Headquarters: ams AG Tobelbaderstrasse 30 8141 Unterpremstaetten, Austria Tel: +43 (0) 3136 500 0 e-Mail: [email protected] Please visit our website at www.ams.com Datasheet AS3642 Ultra Small 500mA Inductive White LED Flash Driver 1 General Description 2 Key Features Total The AS3642 is an inductive high efficient DCDC step up converter driving a current source. 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 current source operates in flash/torch/assist (video/autofocus) and indicator mode. efficiency 4MHz fixed frequency DCDC Boost converter with soft start allows small coils currents Up to 500mA flash current (15.6mA steps) Up to 320mA torch current (10mA steps) 1.35mA,2.9mA,4.4mA or 6mA indicator light current (PWM with 1...4/32 duty cycle) Flash LED(s) cathode connected to ground: Improved thermal performance (ground = heat sink) Simplified PCB layout am lc s on A te G nt st il Adjustable Flash Timer 30ms to 480ms in 30ms steps Flash, 2 The AS3642 is controlled by an I C interface to allow sophisticated control of all settings like currents and timings. Torch, Assist and Indicator Mode Protection functions: Automatic Flash timer to protect the LED Overvoltage and undervoltage Protection Overtemperature Protection LED short circuit protection The complete flash driver solution measures only Available in tiny WL-CSP Packages 2x3 balls 0.5mm pitch, 1.5x1.1x0.6mm package size The AS3642 is available in a space-saving WL-CSP package measuring only 1.5x1.1x0.6mm and operates over the -30ºC to +85ºC temperature range. 3 Applications Figure 1. Typical Operating Circuit Flash/Torch for mobile phones, digital cameras and PDA & "#$* )')* AS3642 www.austriamicrosystems.com/AS3642 (ptr)500mA /1 ch +,- Te ., %%,/,/0 ni & '$( )')" ca ! "#$"#%% lv LED The AS3642 is able to detect a broken coil. Together with the LED short and open detection the AS3642 can be used to verify the connection to its external components and allowing in-circuit test. This reduces test time and simplifies production test procedures. 2 al id High The AS3642 includes flash timer, overvoltage, overtemperature, undervoltage and LED short circuit protection functions. 11mm PCB area. 2 flash driver solution only 11mm AS3642 " 1.2-2 1 - 26 AS3642 Datasheet - P i n o u t 4 Pinout Pin Assignment !" am lc s on A te G nt st il lv al id Figure 2. Pin Assignments (Top View) AS3642 AS3642 Pin Description Table 1. Pin Description for AS3642 Pin Number Pin Name A1 SW DCDC converter switching node - make a short connection to the coil LDCDC GND Power and signal ground - connect to GND and make a short connection to CVOUT A2 B1 LED_OUT B2 VOUT C1 Flash LED current source output DCDC converter output capacitor and supply for AS3642 - make a short connection to CVOUT 2 SCL serial clock input in I C interface SDA serial data input/output for I C interface (needs external pullup resistor) 2 Te ch ni ca C2 Description www.austriamicrosystems.com/AS3642 1.2-2 2 - 26 AS3642 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 Table 3, “Electrical Characteristics,” on page 4 is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Table 2. Absolute Maximum Ratings Min Max Units VOUT, SW to GND -0.3 +7.0 V SCL, SDA, LED_OUT to GND -0.3 VOUT+ 0.3 V max. +7V VOUT to SW -0.3 V Note: Diode between VOUT and SW Input Pin Current without causing latchup -100 +100 +IIN mA Norm: EIA/JESD78 Continuous power dissipation 530 mW PT at 70ºC ambient Continuous power dissipation derating factor 7.2 mW/ºC PDERATE ±2000 V Norm: JEDEC JESD22-A114F lv 1 am lc s on A te G nt st il Continuous Power Dissipation (TA = +70ºC) Comments al id Parameter 2 Electrostatic Discharge ESD HBM ESD CDM ±500 V Norm: JEDEC JESD 22-C101C ESD MM ±100 V Norm: JEDEC JESD 22-A115-A level A +150 ºC Internally limited (overtemperature protection) max. 20000s Temperature Ranges and Storage Conditions Junction Temperature 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) Represents a max. floor life time of unlimited MSL 1 Te ch ni ca 1. Depending on actual PCB layout and PCB used; for peak power dissipation during flashing see document 'AS3642 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) www.austriamicrosystems.com/AS3642 1.2-2 3 - 26 AS3642 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 +5.5V, 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 2.7 3.7 Max Unit Supply Voltage VVINREDUCE Supply Voltage AS3642 functionally working, but not all 1 parameters fulfilled ISHUTDOWN Shutdown Current SCL=L, SDA=L, VVIN<3.7V, 0ºC < TAMB < 50ºC ISTANBY Standby Current interface active, VVIN<3.7V TAMB Operating Temperature D_FUNC 2.5 0.5 -30 VVOUT DCDC Boost output Voltage (pin VOUT) Eta Efficiency ILED_OUT LED_OUT current source output ILED_OUT LED_OUT current source accuracy ILED_OUT LED_OUT ramp time at ILED_OUT=300mA RAMP For high supply voltages the output voltage can reach up to VVOUTMAX (the AS3642 always runs in PWM mode unless VVOUT>VVOUTMAX or during startup) 5.0 V 1.0 µA 0.5 5 µA 25 85 ºC 2.8 ILED_OUT=300mA,VVOUT=4.2V Operating Frequency Current Source V am lc s on A te G nt st il DCDC Step Up Converter fCLK 4.5 lv VVIN al id General Operating Conditions 4.7 82 All internal timings are derived from this oscillator -7.5% 4.0 +7.5% DCDC operating frequency for short pulses (close to 100% operating mode) -7.5% 1.0 +7.5% V % MHz 0 500 mA ILED_OUT=300mA -7 +7 % Ramp-up During startup 0.6 1.0 ms Ramp-down after AS3642 is disabled by interface 0.2 0.7 ms LED_OUT current ripple ILED_OUT = 300mA 10 VILED_COMP LED_OUT current source voltage compliance Minimum voltage between pin VOUT and LED_OUT for operation of the current source (applicable for current_mode=00, 01 and10) 210 350 mV ca ILED_OUT ni RIPPLE mAPP Protection and Fault Detection Functions (see page 10) VVOUT overvoltage protection DCDC Converter Overvoltage Protection 5.0 5.25 5.5 V Current Limit for coil LDCDC (Pin SW) measured at 50% 2 PWM duty cycle maximum 40000s lifetime operation in overcurrent limit 0.7 0.8 0.9 A Flash LED short circuit detection voltage Voltage measured on pin LED_OUT 1.45 1.65 V ch VVOUTMAX Te ILIMIT VLEDSHORT www.austriamicrosystems.com/AS3642 1.2-2 4 - 26 AS3642 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 Table 3. Electrical Characteristics (Continued) Parameter TOVTEMP Overtemperature Protection TOVTEMPHY Condition ST Overtemperature Hysteresis tFLASHTIMER Flash Timer VUVLO Undervoltage 3 Lockout Min Typ Can be adjusted by register flash_timer (see page 18) -7.5% Falling VVIN 2.3 Rising VVIN 144 ºC 5 ºC 30 to +7.5% 480 2.4 VOL Low Level Output Voltage 2 2.5 V VUVLO VUVLO VUVLO +0.05 +0.1 +0.15 V 1.26 VVIN0.2 V 0.0 0.54 V 4 Pins SCL, SDA am lc s on A te G nt st il Low Level Input Voltage ms lv High Level Input Voltage VIL Unit Junction temperature Digital Interface VIH Max al id Symbol Pin SDA with pullup >1k to digital supply <2V, VVIN>2.7V 0.3 V I C interface timings - see Figure 3 on page 6 Minimum time from SDA or SCL going high to 2 first I C start command tWAKEUP Wakeup Time tTIMEOUT I C timeout time fSCLK SCL Clock Frequency 2 500 In flash, assist light and indicator mode if SCL and SDA are L for tTIMEOUT, the AS3642 enters automatically shutdown mode 35 1/ tTIMEO 400 µs ms kHz UT Bus Free Time Between a STOP and START Condition 1.3 µs tHD:STA Hold Time (Repeated) 5 START Condition 0.6 µs tLOW LOW Period of SCL Clock 1.3 µs tHIGH HIGH Period of SCL Clock 0.6 µs tSU:STA Setup Time for a Repeated START Condition 0.6 µs ni 6 0 Data Hold Time ch tHD:DAT ca tBUF 7 0.9 µs Data Setup Time 100 tR Rise Time of Both SDA and SCL Signals 20 + 0.1CB 300 ns tF Fall Time of Both SDA and SCL Signals 20 + 0.1CB 300 ns tSU:STO Setup Time for STOP Condition 0.6 CB Capacitive Load for Each Bus Line Te tSU:DAT CB — total capacitance of one bus line in pF www.austriamicrosystems.com/AS3642 1.2-2 ns µs 400 pF 5 - 26 AS3642 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 Table 3. Electrical Characteristics (Continued) Symbol Parameter CI/O I/O Capacitance (SDA, SCL) Condition Min Typ Max Unit 10 pF am lc s on A te G nt st il lv al id 1. Limited to max. 5V due to overvoltage protection circuit on pin VOUT 2. Due to slope compensation of the current limit, ILIMIT changes with duty cycle - see Figure 16 on page 9. 3. Due to the architecture (the supply of the AS3642 is connected to the output VOUT), the undervoltage lockout is only detected when the DCDC converter is not switching 4. The logic input levels VIH and VIL allow for 1.8V supplied driving circuit (70%/30% of 1.8V) 5. After this period, the first clock pulse is generated. 6. A device must internally provide a hold time of at least 300ns for the SDA signal (referred to the VIHMIN of the SCL signal) to bridge the undefined region of the falling edge of SCL. 7. A fast-mode device can be used in a standard-mode system, but the requirement tSU:DAT = to 250ns must then be met. This is automatically the case if the device does not stretch the LOW period of the SCL signal. If such a device does stretch the LOW period of the SCL signal, it must output the next data bit to the SDA line tR max + tSU:DAT = 1000 + 250 = 1250ns before the SCL line is released. Timing Diagrams 2 Figure 3. I C interface Timing Diagram SDA tBUF tLOW tR ca SCL tHD:STA tF tHD:STA ni tHD:DAT tHIGH tSU:STA tSU:STO tSU:DAT REPEATED START Te ch STOP START www.austriamicrosystems.com/AS3642 1.2-2 6 - 26 AS3642 Datasheet - Ty p i c a l O p e r a t i n g C h a r a c t e r i s t i c s 7 Typical Operating Characteristics VVIN = 3.7V, TA = +25ºC (unless otherwise specified) Figure 4. DCDC Efficiency vs. VVIN 85 85 80 75 70 65 IOUT = 50mA IOUT = 120mA IOUT = 220mA IOUT = 320mA IOUT = 500mA 55 70 65 pulseskip is used for currents above 320mA 60 55 IOUT = 50mA IOUT = 120mA IOUT = 220mA IOUT = 320mA IOUT = 500mA 50 3,9 2,7 4,3 Input Voltage (V) 1V/Div VVIN,VLED_OUT,VOUT IVIN ca 100mA/Div VVIN,VLED_OUT,VOUT ILED_OUT 4,3 250µs/Div 1V/Div 20mA/Div ILED_OUT ch ILED_OUT VLED_OUT Figure 9. VOUT / ILED_OUT ripple, ILED_OUT = 300mA ni Figure 8. ILED Startup (ILED_OUT=51.6mA) VVIN,VLED_OUT,VOUT 3,9 Figure 7. IVIN Startup (ILED_OUT=300mA) 250µs/Div Te 3,5 Input Voltage (V) Figure 6. ILED Startup (ILED_OUT=300mA) 50µs/Div www.austriamicrosystems.com/AS3642 3,1 1V/Div 3,5 100mA/Div 3,1 50mV/Div 2,7 20mA/Div 50 75 am lc s on A te G nt st il 60 80 lv 90 Efficiency PLED/PVIN (%) 95 DCDC Efficiency (%) 90 al id Figure 5. Application Efficiency (PLED/PVIN) vs. VVIN 100 100ns/Div 1.2-2 7 - 26 AS3642 Datasheet - Ty p i c a l O p e r a t i n g C h a r a c t e r i s t i c s Figure 10. ILED Rampdown (ILED_OUT=300mA) Figure 11. ILED_OUT Linearity of current sink 400 300 al id ILED_OUT (mA) IOUT = 50mA IOUT = 120mA IOUT = 220mA IOUT = 320mA IOUT = 500mA 200 100 0 0 250µs/Div 0,8 1,2 1,6 2 2,4 am lc s on A te G nt st il VOUT-LED_OUT (V) Figure 12. ILED_OUT vs. TAMB 321 0,4 lv ILED_OUT 100mA/Div 1V/Div VVIN,VLED_OUT,VOUT 500 Figure 13. Oscillator frequency fCLK vs. TAMB 4,00 Frequency (MHz) ILED_OUT (mA) 3,98 320 319 3,96 3,94 3,92 10 30 50 3,90 -30 70 10 30 50 70 VLED_OUT, VOUT Figure 15. DCDC fCLK change 4MHz->1MHz(51mA) ISW ISW 100mA/Div 1V/Div ni Te ch VLED_OUT, VOUT Figure 14. DCDC fCLK change 4MHz->1MHz(300mA) 5µs/Div www.austriamicrosystems.com/AS3642 -10 Ambient Temperature (C) ca Ambient Temperature (C) 1V/Div -10 50mA/Div 318 -30 5µs/Div 1.2-2 8 - 26 AS3642 Datasheet - D e t a i l e d D e s c r i p t i o n 8 Detailed Description The AS3642 is a high performance DCDC step up converter with internal PMOS and NMOS switches. The switching frequency of 4MHz allows the use of tiny coils. Its output is connected to a flash LED by an internal current source. 2 The AS3642 is controlled by an I C interface. All timings and currents can be accurately adjusted by this interface. It support following operating modes: al id 1. Flash mode (enabled by mode=11): The LED current is defined by register flash_current. A timer defines the output flash duration (30ms...480ms 2 lv in 30ms steps defined by register flash_timer). The flash is started immediately after the end of the I C command. If SCL and SDA are L for more than tTIMEOUT, shutdown mode is automatically entered. 2. Assist light mode (=video or torch light mode) (enabled by mode=10): The LED current is defined by register assist_current. The current is enabled until another mode is chosen by the interface. If SCL and SDA are L for more than tTIMEOUT, shutdown mode is automatically entered. 3. Indicator light mode (enabled by mode=01): 1 Internal Circuit am lc s on A te G nt st il The LED current is PWM modulated by 1/32, 2/32, 3/32 or 4/32 (defined by register ind_current resulting in a effective current of 1.35mA / 2.9mA / 4.4mA or 6.0mA. The current is enabled until another mode is chosen by the interface. If SCL and SDA are L for more than tTIMEOUT, shutdown mode is automatically entered 4. Shutdown mode (mode=00), SCL=0V, SDA=0V: The DCDC and the current source is disabled and the AS3642 is configured to draw minimum current. The AS3642 includes a fixed frequency DCDC step-up with accurate startup control. Together with the output current source (on LED_OUT) it includes protection and safety functions as shown in the following internal blockdiagram: Figure 16. AS3642 internal circuit + !"#$5$8' 7 7 4!&)5/' + ch ;+2 + &55/ 7 /# ca 2 3 +. +/# #6/+/# !"#$%$&%' 8*5/ 2 &)5/ ,-+., +/#+ ++ 0 + . #6/ ni : :0 +60 ( ++ !"#$)$*%' 2 *(- 9 Te 3 /#. AS3642 1. The PWM modulation frequency is 31.25kHz to avoid audible noise on the external capacitors. www.austriamicrosystems.com/AS3642 1.2-2 9 - 26 AS3642 Datasheet - D e t a i l e d D e s c r i p t i o n The DCDC converter always operates in PWM mode (exception: PFM mode is allowed during startup) to reduce EMI in EMI sensitive systems. For flash and assist light mode and high duty cycles close to 100% on-time (maximum duty cycle) of the PMOS, the DCDC converter can switch into a 1MHz operating mode and maximum duty cycle to improve efficiency for this load condition. The DCDC converter returns back to its normal 4MHz operating frequency when load or supply conditions change. Due to this switching between two fixed frequencies the noise spectrum of the system is exactly defined and predictable. If improved efficiency is required, the fixed switching between 1MHz / 4MHz can be 2 The internal circuit for switching between these two frequencies is shown in Figure 17: Figure 17. Internal circuit of 4MHz/1Mhz selection ! 3 lv AS3642 "! #$# am lc s on A te G nt st il $ al id disabled by freq_switch_on (see page 16)=0 . In this case pulseskip will be used. ,- #%&!'' ()!*+ ./. 012-#$.," $ External Strobe Input To start the flash operation by an hardware input using an external strobe input, use schematic shown in Figure 18: Figure 18. External strobe input AS3642 & " ! " #$$% '#( Te ch ni ca To enable this function, program the flash timer with the exact flash duration (by programming flash_timer) and set external_strobe=1. The AS3642 waits for an external strobe signal on pin LED_OUT and starts the flash pulse with a duration defined by flash_timer. 2. If current_mode=11 (500mA operating mode), the AS3642 will always use only 4Mhz. www.austriamicrosystems.com/AS3642 1.2-2 10 - 26 AS3642 Datasheet - D e t a i l e d D e s c r i p t i o n Protection and Fault Detection Functions The protection functions protect the AS3642 and the LED(s) against physical damage. In most cases a register bit is 3 set, which can be readout with the interface. The fault bits are cleared by a readout of the fault register. DCDC Overvoltage Protection al id In case of no or a broken LED at the pin LED_OUT and an enabled DCDC converter, the voltage on VOUT rises until it reaches VVOUTMAX (overvoltage condition) and the voltage across the current source does not reach regulation (VOUT-VLED < VILED_COMP). If this condition is detected, the DCDC converter is stopped, the current sources are dis4 abled and the bit fault_ovp (see page 19) is set. DCDC Broken Coil Detection 2 lv If the coil LDCDC is broken, the AS3642 is not powered by the pin SW connected to VOUT by the internal switch. Due to the protection diodes between SCL to VOUT and SDA to VOUT, the AS3642 can be powered through these diodes. The AS3642 detects this error condition by comparing the voltage on SCL and VOUT. If the voltage on VOUT is lower am lc s on A te G nt st il compared to the voltage on SCL, the AS3642 will ignore any I C write commands. Therefore the application can simply detect this condition. Note: Due to the broken coil detection, the high levels of SDA and SCL should be always below the supply voltage. LED Short Circuit Protection After the startup of the DCDC converter, the voltage on LED_OUT is continuously monitored and compared against VLEDSHORT. If the voltage stays below VLEDSHORT, the DCDC is stopped (as a shorted LED is assumed), the current sources are disabled and the bit fault_led_short (see page 19) is set. Overtemperature Protection The junction temperature of the AS3642 is continuously monitored. If the temperature exceeds TOVTEMP, the DCDC is stopped, the current sources are disabled and the bit fault_overtemp (see page 19) is set. The driver cannot be reenabled unless the junction temperature drops below TOVTEMP-TOVTEMPHYST. Flash Timer The duration of the flash is defined by the register flash_timer (see page 18). After the timer expires, the DCDC is stopped and the flash current source (on pin LED_OUT) is disabled. Supply undervoltage Protection If the voltage on the pin VOUT (=battery voltage) is or falls below VUVLO, the AS3642 is kept in shutdown state and in all registers are set to their default state. ca Note: During operation of the DCDC converter, the supply undervoltage protection will still monitor the DCDC output voltage only. Therefore the supply undervoltage protection will only monitor the battery voltage if the DCDC converter is switched off and the output capacitor is discharged down to the supply voltage. ni Wakeup Circuit - Power off detection Te ch In flash, assist light and indicator mode (register mode (page 18)=01, 10 or 11), if SCL and SDA are L for more than tTIMEOUT, shutdown mode is automatically entered. This feature automatically detects a power-off of the controlling circuit driving SCL and SDA (VDD_I/F goes to 0V) - the internal circuit is shown in Figure 19: 3. Except overtemperature protection bit fault_overtemp: This bit can be cleared once the temperature drops below TOVTEMP-TOVTEMPHYST. 4. In indicator mode (mode=01) the register fault_ovpi s never set (the overvoltage protection is nevertheless operating) www.austriamicrosystems.com/AS3642 1.2-2 11 - 26 AS3642 Datasheet - D e t a i l e d D e s c r i p t i o n Figure 19. Device Shutdown and Wakeup !!" '()(* )))( + &+ !!" $ am lc s on A te G nt st il AS3642 lv al id "& "#!$%" I2C Serial Data Bus 2 The AS3642 supports the I C bus protocol. A device that sends data onto the bus is defined as a transmitter and a device receiving data as a receiver. The device that controls the message is called a master. The devices that are controlled by the master are referred to as slaves. A master device that generates the serial clock (SCL), controls the bus access, and generates the START and STOP conditions must control the bus. The AS3642 operates as a slave on 2 the I C bus. Within the bus specifications a standard mode (100kHz maximum clock rate) and a fast mode (400kHz maximum clock rate) are defined. The AS3642 works in both modes. Connections to the bus are made through the open-drain I/O lines SDA and SCL. The following bus protocol has been defined (Figure 20): Data transfer may be initiated only when the bus is not busy. During data transfer, the data line must remain stable whenever the clock line is HIGH. Changes in the data line while the clock line is HIGH are interpreted as control signals. Accordingly, the following bus conditions have been defined: ca Bus Not Busy Both data and clock lines remain HIGH. Start Data Transfer ni A change in the state of the data line, from HIGH to LOW, while the clock is HIGH, defines a START condition. Stop Data Transfer ch A change in the state of the data line, from LOW to HIGH, while the clock line is HIGH, defines the STOP condition. Data Valid Te The state of the data line represents valid data when, after a START condition, the data line is stable for the duration of the HIGH period of the clock signal. The data on the line must be changed during the LOW period of the clock signal. There is one clock pulse per bit of data. Each data transfer is initiated with a START condition and terminated with a STOP condition. The number of data bytes transferred between START and STOP conditions are not limited, and are determined by the master device. The information is transferred byte-wise and each receiver acknowledges with a ninth bit. www.austriamicrosystems.com/AS3642 1.2-2 12 - 26 AS3642 Datasheet - D e t a i l e d D e s c r i p t i o n Acknowledge Each receiving device, when addressed, is obliged to generate an acknowledge after the reception of each byte. The master device must generate an extra clock pulse that is associated with this acknowledge bit. al id A device that acknowledges must pull down the SDA line during the acknowledge clock pulse in such a way that the SDA line is stable LOW during the HIGH period of the acknowledge-related clock pulse. Of course, setup and hold times must be taken into account. A master must signal an end of data to the slave by not generating an acknowledge bit on the last byte that has been clocked out of the slave. In this case, the slave must leave the data line HIGH to enable the master to generate the STOP condition. 2 lv Figure 20. Data Transfer on I C Serial Bus SDA MSB SLAVE ADDRESS am lc s on A te G nt st il R/W DIRECTION BIT ACKNOWLEDGEMENT SIGNAL FROM RECEIVER ACKNOWLEDGEMENT SIGNAL FROM RECEIVER SCL 1 2 6 7 8 9 1 2 3-8 8 9 ACK START CONDITION REPEATED IF MORE BYTES ARE TRANSFERRED STOP CONDITION OR REPEATED START CONDITION Depending upon the state of the R/W bit, two types of data transfer are possible: ni ca 1. Data transfer from a master transmitter to a slave receiver. The first byte transmitted by the master is the slave address. Next follows a number of data bytes. The slave returns an acknowledge bit after each received byte. Data is transferred with the most significant bit (MSB) first. 2. Data transfer from a slave transmitter to a master receiver. The master transmits the first byte (the slave address). The slave then returns an acknowledge bit, followed by the slave transmitting a number of data bytes. The master returns an acknowledge bit after all received bytes other than the last byte. At the end of the last received byte, a “not acknowledge” is returned. The master device generates all of the serial clock pulses and the START and STOP conditions. A transfer is ended with a STOP condition or with a repeated START condition. Since a repeated START condition is also the beginning of the next serial transfer, the bus is not released. Data is transferred with the most significant bit (MSB) first. The AS3642 can operate in the following two modes: Te ch 1. Slave Receiver Mode (Write Mode): Serial data and clock are received through SDA and SCL. After each byte is received an acknowledge bit is transmitted. START and STOP conditions are recognized as the beginning and end of a serial transfer. Address recognition is performed by hardware after reception of the slave address and direction bit (see Figure 21). The slave address byte is the first byte received after the master generates the START condition. The slave address byte contains the 7-bit AS3642 address, which is 0110000, 5 followed by the direction bit (R/W), which, for a write, is 0. After receiving and decoding the slave address byte the device outputs an acknowledge on the SDA line. After the AS3642 acknowledges the slave address + write bit, the master transmits a register address to the AS3642. This sets the register pointer on the AS3642. The master may then transmit zero or more bytes of data, with the AS3642 acknowledging each byte received. 5. The address for writing to the AS3642 is 60h = 01100000b www.austriamicrosystems.com/AS3642 1.2-2 13 - 26 AS3642 Datasheet - D e t a i l e d D e s c r i p t i o n The address pointer will increment after each data byte is transferred. The master generates a STOP condition to terminate the data write. 2. Slave Transmitter Mode (Read Mode): The first byte is received and handled as in the slave receiver mode. However, in this mode, the direction bit indicates that the transfer direction is reversed. Serial data is transmitted on SDA by the AS3642 while the serial clock is input on SCL. START and STOP conditions are recognized as the beginning and end of a serial transfer (Figure 22 and Figure 23). The slave address byte is the first byte received after the master generates a START condition. The slave address byte contains the 7-bit AS3642 6 al id address, which is 0110000, followed by the direction bit (R/W), which, for a read, is 1. After receiving and decoding the slave address byte the device outputs an acknowledge on the SDA line. The AS3642 then begins to transmit data starting with the register address pointed to by the register pointer. If the register pointer is not written to before the initiation of a read mode the first address that is read is the last one stored in the register pointer. The AS3642 must receive a “not acknowledge” to end a read. am lc s on A te G nt st il 0110000 <RW> <Slave Address> S lv Figure 21. Data Write - Slave Receiver Mode 0 A <Word Address (n)> <Data(n)> XXXXXXXX XXXXXXXX A S - Start A - Acknowledge (ACK) P - Stop <Data(n+X)> <Data(n+1)> A XXXXXXXX A XXXXXXXX A P NA P Data Transferred (X + 1 Bytes + Acknowledge) <Slave Address> 0110000 1 <Data(n+1)> <Data(n)> A XXXXXXXX A ca S <RW> Figure 22. Data Read (from Current Pointer Location) - Slave Transmitter Mode A XXXXXXXX A XXXXXXXX Data Transferred (X + 1 Bytes + Acknowledge) Note: Last data byte is followed by a NACK Te ch ni S - Start A - Acknowledge (ACK) P - Stop NA - Not Acknowledge (NACK) XXXXXXXX <Data(n+X)> <Data(n+2)> 6. The address for read mode from the AS3642 is 61h = 01100001b www.austriamicrosystems.com/AS3642 1.2-2 14 - 26 AS3642 Datasheet - D e t a i l e d D e s c r i p t i o n 0 XXXXXXXX A XXXXXXXX Sr 0110000 A XXXXXXXX 1 A <Data(n+X)> A XXXXXXXX NA Data Transferred (X + 1 Bytes + Acknowledge) Note: Last data byte is followed by a NACK P Te ch ni ca am lc s on A te G nt st il S - Start Sr - Repeated Start A - Acknowledge (ACK) P - Stop NA - Not Acknowledge (NACK) A <Data(n+2)> <Data(n+1)> <Data(n)> XXXXXXXX A al id 0110000 <Slave Address> lv S <Word Address (n)> <RW> <RW> Figure 23. Data Read (Write Pointer, Then Read) - Slave Receive and Transmit www.austriamicrosystems.com/AS3642 1.2-2 15 - 26 AS3642 Datasheet - D e t a i l e d D e s c r i p t i o n Register Description Table 4. Design Info Register Design Info Register Addr: 0 This register has a fixed ID Bit Name 7:0 fixed_id Default Access 13h Description 2 This is a fixed identification (e.g. to verify the I C communication) R Table 5. Version Control Register Version Control Register Addr: 1 lv This register defines design versions al id Bit Bit Name Default Access Description 3:0 version Xh R AS3642 version number 7:4 reserved Xh R reserved - don’t use am lc s on A te G nt st il Bit Table 6. Current Set Register Addr: 2 Bit Current Set Register This register defines the Current Settings Bit Name Default Access Description Define the current on pin LED_OUT 00 1 1:0 current_mode 00 R/W 10 LED_OUT current is defined by ind_current, assist_current and flash_current 01 LED_OUT current is defined by register 2, bits <7:3> LSB = 10mA, full range = 320mA 11 LED_OUT current is defined by register 2, bits <7:3> LSB = 15.625mA, full range = 500mA Exact frequency switching between 4MHz/1MHz for assist and flash modes for operation close to maximum pulsewidth - see Figure 17 on page 10 2 2 1 R/W ch ni ca freq_switch_on Te 4:3 5 ind_current 0 Pulseskip operation is allowed for all modes results in better efficiency 1 In flash and assist light mode, the DCDC is running at 4MHz or 1MHz (pulseskip is disabled) results in improved noise performance Define the current on pin LED_OUT in indicator mode if current_mode=00 or 10 10 R/W 00 ILED_OUT = 1.35mA (PWM with 1/32 duty cycle) 01 ILED_OUT = 2.9mA (PWM with 2/32 duty cycle) 10 ILED_OUT = 4.4mA (PWM with 3/32 duty cycle) 11 ILED_OUT = 6.0mA (PWM with 4/32 duty cycle) Define the current on pin LED_OUT in assist light mode if current_mode=00 or 10 assist_current www.austriamicrosystems.com/AS3642 1 R/W 0 ILED_OUT = 51.6mA 1 ILED_OUT = 72.3mA 1.2-2 16 - 26 AS3642 Datasheet - D e t a i l e d D e s c r i p t i o n Table 6. Current Set Register (Continued) Current Set Register Addr: 2 Bit This register defines the Current Settings Bit Name Default Access Description flash_current 7:6 10 R/W 00 ILED_OUT = 260mA 01 ILED_OUT = 280mA 10 ILED_OUT = 300mA 11 ILED_OUT = 320mA al id Define the current on pin LED_OUT in flash mode if current_mode=00 or 10 lv Define the current on pin LED_OUT for flash and assist mode (mode=10 or 11) if current_mode=01 or 11 am lc s on A te G nt st il current_mode = 01 11 current 7:3 16h R/W 0 ILED_OUT = 10mA 1 ILED_OUT = 20mA 31.25mA 2 ILED_OUT = 30mA 46.875mA 15.6mA ... 1F ILED_OUT = 320mA 500mA Te ch ni ca 1. Before changing current_mode register, write 0xA1 to register 0x80h (password protection). This sequence is added to protect the flash LED against unintentional high currents for flash systems designed only up to 320mA. Additionally do not change this register if the DCDC is operating. 2. For currents above 320mA, the AS3642 will always enable pulseskip mode (register setting of freq_switch_on has no effect) www.austriamicrosystems.com/AS3642 1.2-2 17 - 26 AS3642 Datasheet - D e t a i l e d D e s c r i p t i o n Table 7. Control Register Control Register Addr: 3 Bit This register defines the operating mode and different protection 2 functions in I C interface Bit Name Default Access Description 0h 30ms 1h 60ms 2h 90ms 3h 120ms 150ms default value lv 4h al id Define the duration of the flash timer 180ms 6h 210ms am lc s on A te G nt st il 5h flash_timer 3:0 4h R/W 7h 240ms 8h 270ms 9h 300ms Ah 330ms Bh 360ms Ch 390ms Dh 420ms Eh 450ms Fh 480ms AS3642 operating mode selection mode 00 ca 5:4 reserved 0 ch Te 7 external_strobe 3 0 Shutdown mode 01 Indicator light mode with ind_current 10 Assist light mode with assist_current 11 Flash mode with duration flash_timer with flash_current (if current_mode=00b or 10b) or current (if current_mode=10b or 11b) 1 2 R reserved - don’t use External strobe signal from pin LED_OUT ni 6 R/W 00 0 no external strobe 1 A flash pulse with current defined by flash_current (if current_mode=00b or 10b) or current (if current_mode=10b or 11b) register is triggered on a rising edge on LED_OUT (e.g. due to an external signal pulling it high). At the same time this register is automatically cleared. After the flash pulse (duration defined by flash_timer) the AS3642 returns to shutdown mode. R/W Note: Setting this bit automatically sets mode (see page 18)=11 (flash mode) A ongoing flash started with external_strobe can be stopped by writing ‘0’ to external_strobe and ‘00’ to mode. www.austriamicrosystems.com/AS3642 1.2-2 18 - 26 AS3642 Datasheet - D e t a i l e d D e s c r i p t i o n 1. Before changing mode register to 01, write 0xA1 to register 0x80h (password protection). 2. Torch mode and assist light mode share the same operating mode and identical currents. 3. Before changing external_strobe register to 01, write 0xA1 to register 0x80h (password protection). Table 8. Fault Register Addr: 4 al id Fault Register This register identifies all the different fault conditions and provide information about the LED detection Bit Bit Name 4:0 reserved Default Access 0 Description R reserved - don’t use fault_overtemp 5 0 R lv see Overtemperature Protection on page 11 0 No fault 1 Junction temperature limit has been exceeded am lc s on A te G nt st il see LED Short Circuit Protection on page 11 fault_led_short 6 0 R 0 No fault 1 A shorted LED is detected (pin LED_OUT) see DCDC Overvoltage Protection on page 11 fault_ovp 7 Register Map Table 9. Register Map Register Definition Version Control Current Set 13h 1 XXh 2 B4h 3 4 No fault 1 An overvoltage condition is detected (pin VOUT) 04h 00h b6 b5 b4 b3 b2 b1 b0 fixed_id reserved flash_current version assist_c urrent ind_current current if current_mode=10 or 11 external reserve _strobe d mode fault_ov fault_le fault_ov p d_short ertemp freq_swi tch_on current_mode flash_timer reserved Te ch Fault 0 ni Control 0 Content b7 Design Info R Default ca Name Addr 0 www.austriamicrosystems.com/AS3642 1.2-2 19 - 26 AS3642 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 2 The AS3642 can be directly connected to an (existing) I C bus (e.g. from the baseband or camera processor). All functions are accessible by this interface. An strobe input can be done by adding a diode (with an optional resistor in series) to the LED_OUT pin. Setting the register bit external_strobe=1 enable this input as a strobe input. The duration 2 al id of the flash is programmed by the I C interface, but the exact starting time is defined by this input- see External Strobe Input on page 10. External Components Input Capacitor CVIN Table 10. Recommended Input Capacitor C TC Code ESR Rated Voltage Size Manufacturer am lc s on A te G nt st il Part Number lv 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. CL05A395MQ5NQKL 4.7µF +/-10% >1.6µF @ VVIN X5R <20m 6V3 0402 Samsung ElectroMechancs www.sem.samsung.co.kr If a different input capacitor is chosen, ensure similar ESR value and at least 1.6µF capacitance at the maximum input supply voltage. Larger capacitor values (C) may be used without limitations. 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 11. Recommended Output Capacitor Part Number TC Code ESR Rated Voltage Size Manufacturer 2x1.5µF +/-15% X5R <10m 6V3 0405 2-array Panasonic www.panasonic.com Samsung ElectroMechancs www.sem.samsung.co.kr ca ECJUNBPJ155K C CL14A185MQ8SAKL ni If a different output capacitor is chosen, ensure similar ESR values and at least 1.0µF capacitance at maximum output voltage. ch Inductor LDCDC The fast switching frequency (4MHz) of the AS3642 allows for the use of small SMDs for the external inductor. The 2 Te inductor should have low DC resistance (DCR) to reduce the I R power losses - high DCR values will reduce efficiency. Table 12. Recommended Inductor Part Number L DCR L @ 0.9A Size Manufacturer LQM21PN1R0NGC 1.1µH 100m >0.7µH 2x1.25x0.9mm Murata www.murata.com ELGTEA1R0SN 1.0µH >0.7µH 2x1.25x0.9mm Panasonic www.panasonic.com www.austriamicrosystems.com/AS3642 1.2-2 20 - 26 AS3642 Datasheet - A p p l i c a t i o n I n f o r m a t i o n Table 12. Recommended Inductor (Continued) L DCR L @ 0.9A Size Manufacturer CIG21K1R0SCE 1.17µH 135m >0.7µH 2x1.25x0.9mm Samsung ElectroMechancs www.sem.samsung.co.kr CKP2012N1R0M 1.0µH 110m >0.7µH 2x1.25x0.9mm Taiyo Yuden www.t-yuden.com MLP2012L1R0MT 1.0µH >0.7µH 2x1.25x0.9mm TDK www.tdk.com MDT2012-CR1R0AN 1.0µH >0.7µH 2x1.25x0.9mm Toko www.toko.co.jp 110m al id Part Number lv If a different inductor is chosen, ensure similar DCR values and at least 0.7µH inductance at 0.9A input current. LED Use LED and optics as required by the system. Part Number CERAMOS LUW C9SM LXCL-PWF3 am lc s on A te G nt st il Table 13. Recommended LEDs Name Lumen @ 300mA Size Manufacturer Ceramos 55 2.04x1.64x0.75mm Osram Opto Semiconductors www.osram-os.com Luxeon PWF3 30 2.04x1.64x0.7mm Philips Lumileds www.philipslumileds.com 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 - LDCDC - pin SW - pin GND - CVIN Loop2: CVIN - LDCDC - pin SW - pin VOUT - CVOUT - pin GND - CVIN Te ch ni ca 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 ‘ground via’ in Figure 24. www.austriamicrosystems.com/AS3642 1.2-2 21 - 26 AS3642 Datasheet - A p p l i c a t i o n I n f o r m a t i o n Figure 24. Layout recommendation al id !" lv AS3642 am lc s on A te G nt st il Note: If component placement rules allow, move all components close to the AS3642 to reduce the area and length of Loop1 and Loop2. The recommended PCB pad size for the AS3642 is 250µm. Application Self Testing Guideline Using the in-build self testing features of the AS3642, the errors as shown in Figure 25 during the assembling and soldering of the AS3642, can be detected - this simplifies and can reduce cost during manufacturing: Figure 25. Self Testing - Detecting Assembling and Soldering Errors ! ca ch ! ni AS3642 Te The self testing procedure is simple: www.austriamicrosystems.com/AS3642 1.2-2 22 - 26 AS3642 Datasheet - A p p l i c a t i o n I n f o r m a t i o n 1. Write 0x20 into register 0x03 (Control register) [Enable assist light with default 72mA]. 7 2 2. Read back register 0x03 - must return 0x20, otherwise LDCDC or I C (SCL or SDA) is broken 3. Write 0x00 into register 0x03 [Power off] 4. Read register 0x04 (Fault register) - must return 0x00, otherwise the LED is open or shorted Table 14. How-to identify errors al id See Table 14 to identify the different possible soldering errors: Identified by SCL or SDA broken writing 0x20 to 0x03 and read back of register 0x03 does not return 0x20 LDCDC broken writing 0x20 to 0x03 and read back of register 0x03 does not return 0x20 - see DCDC Broken Coil Detection on page 11 Flash LED shorted register fault_led_short (see page 19) is set Flash LED open register fault_ovp (see page 19) is set lv Error am lc s on A te G nt st il Typical I2C programming example A typical use case for the AS3642 is to generate a 480ms, 500mA flash pulse. The programming example is shown in Table 15: 2 Table 15. I C Programing Example - 500mA, 480ms flash pulse Sequence C-Syntax Purpose/Action write 0xA1 to register 0x80h AMSWriteByte(0x80,0xA1); Use password to unlock next I C write write 0xFF to register 0x02h AMSWriteByte(0x02,0xFF); Set 500mA mode (current_mode (page 16)=11b) and current (page 17) to 500mA write 0x3F to register 0x03h AMSWriteByte(0x03,0x3F); Set flash_timer (page 18) to 480ms and mode (page 18) to flash (which automatically fires the flash and stops it after flash_timer expired) 2 the AS3642 automatically returns to shutdown mode Te ch ni ca - no further action required - 7. Alternative testing method: Instead of reading the internal registers, the current into the AS3642 can be measured. During assist light mode, the supply current must increase by at least 60mA. If an error is detected, the current source and the DCDC is automatically switched off - see Protection and Fault Detection Functions on page 11 www.austriamicrosystems.com/AS3642 1.2-2 23 - 26 AS3642 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 26. 6pin WL-CSP Marking lv al id Note: AS3642 <Code> Encoded Datecode (4 characters) am lc s on A te G nt st il Line 1: Line 2: Figure 27. 6pin WL-CSP Package Dimensions * ni * & & ) * * # ch " ## & ca & # $%& '%( ! Te The coplanarity of the balls is 40µm. www.austriamicrosystems.com/AS3642 1.2-2 24 - 26 AS3642 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 16. Table 16. Ordering Information Description Delivery Form Package AS3642-ZWLT Ultra Small 500mA Inductive White LED Flash Driver Tape & Reel 6-pin WL-CSP (1.5mm x 1.1mm x 0.6mm) RoHS compliant / Pb-Free / Green al id Model Note: All products are RoHS compliant and austriamicrosystems green. Buy our products or get free samples online at ICdirect: http://www.austriamicrosystems.com/ICdirect lv Technical support is found at http://www.austriamicrosystems.com/Technical-Support Note: AS3642-ZWLT am lc s on A te G nt st il For further information and requests, please contact us mailto:[email protected] or find your local distributor at http://www.austriamicrosystems.com/distributor Te ch ni ca AS3642Z ... Temperature Range: -30ºC - 85ºC WL ... Wafer Level Chip Scale Package (WL-CSP) T ... Delivery Form: Tape & Reel www.austriamicrosystems.com/AS3642 1.2-2 25 - 26 AS3642 Datasheet - O r d e r i n g I n f o r m a t i o n Copyrights Copyright © 1997-2011, austriamicrosystems AG, Schloss Premstaetten, 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. al id All products and companies mentioned are trademarks or registered trademarks of their respective companies. Disclaimer am lc s on A te G nt st il lv Devices sold by austriamicrosystems AG are covered by the warranty and patent indemnification provisions appearing in its Term of Sale. austriamicrosystems 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. austriamicrosystems 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 austriamicrosystems 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 lifesustaining equipment are specifically not recommended without additional processing by austriamicrosystems 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. ca The information furnished here by austriamicrosystems AG is believed to be correct and accurate. However, austriamicrosystems 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. 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