IS32LT3125A-GRLA3-TR

IS32LT3125/3125A SINGLE CHANNEL 250mA LED DRIVER WITH FAULT DETECTION June 2020 GENERAL DESCRIPTION FEATURES The IS32LT3125/3125A is a linear programmable current regulator consisting of a single output channel capable of 250mA. It features an EN pin to enable and disable the output channel’s current source. It supports PWM dimming via EN pin or power supply modulation (PSM). The UV pin can be used to set external VCC undervoltage lockout threshold via a resistor divider. An external resistor programs the current level for the channel current source. In addition, IS32LT3125/3125A integrates fault protection for LED open/short, ISET pin open/short and over temperature condition for robust operation. Detection of these failures is reported by the FAULTB pin. When a fault is detected the device will disable itself and output an open drain low signal. Multiple devices can have their FAULTB pins connected to create a “one-fail-all-fail” condition. Under a fault condition, the IS32LT3125 will sink 30mA ICC current, while the IS32LT3125A will sink a lower 2mA (Max.) ICC.   The IS32LT3125/3125A is targeted at the automotive market with end applications to include interior and exterior lighting. For 12V automotive applications the low dropout driver can support one to several LEDs on the output channel. Both devices are offered in a small thermally enhanced SOP-8-EP package.          Single channel, sources up to 250mA 5.0V to 28V input supply voltage range - Withstand 42V load dump External resister sets source current Programmable VCC undervoltage lockout to match the LED stack for High Side PWM operation Shared fault flag for multiple devices operation Fault protection with flag output: - LED string open/short - OUT pin short to VCC/GND - ISET pin open/short - Thermal shutdown - ICC set to 30mA under fault condition (IS32LT3125 only) External CSTOR capacitor keeps fault status during start/stop operation SOP-8-EP package AEC-Q100 Qualified Operating temperature range from -40°C ~ +125°C APPLICATIONS  Automotive interior/exterior lighting: - Turn signal light - Tail/stop light - Position light - Dome light TYPICAL APPLICATION CIRCUIT Figure 1 Lumissil Microsystems – www.lumissil.com Rev.A, 06/08/2020 Typical Application Circuit 1 IS32LT3125/3125A Figure 2 Typical Application Circuit (Several Devices in Parallel with FAULTB Interconnection) Note 1: For PSM dimming application, high CVCC capacitor value will affect the dimming accuracy. To get better dimming performance, recommend 0.1µF for it. Lumissil Microsystems – www.lumissil.com Rev.A, 06/08/2020 2 IS32LT3125/3125A PIN CONFIGURATION Package Pin Configuration (Top view) SOP-8-EP PIN DESCRIPTION No. Pin Description 1 CSTOR 2 ISET 3 FAULTB 4 OUT Output current source channel. 5 VCC Power supply input pin. 6 UV External under voltage lockout threshold detection pin. 7 EN Enable pin. It can be used for LED PWM dimming or device ON/OFF. 8 GND Ground. Thermal Pad Must be electrically connected to GND plane for better thermal dissipation. Keep-alive capacitor to maintain the deglitch timer and fault latch status with collapsing VCC. Output current setting for channel. Connect a resistor between this pin and GND to set the maximum output current. Open drain output with internal pull up to 4.5V. Active low to indicate the fault conditions. This pin is also an input pin. Pulling this pin low will shutdown the device. Lumissil Microsystems – www.lumissil.com Rev.A, 06/08/2020 3 IS32LT3125/3125A ORDERING INFORMATION Automotive Range: -40°C to +125°C Order Part No. Package QTY/Reel IS32LT3125-GRLA3-TR IS32LT3125A-GRLA3-TR SOP-8-EP, Lead-free 2500 Copyright  ©  2020  Lumissil  Microsystems. All  rights  reserved.  Lumissil Microsystems reserves  the  right  to  make  changes  to  this  specification  and  its  products  at  any  time  without  notice.  Lumissil  Microsystems  assumes  no  liability  arising  out  of  the  application  or  use  of  any  information,  products  or  services described herein. Customers are advised to obtain the latest version of this device specification before relying on any published information and  before placing orders for products.  Lumissil Microsystems does not recommend the use of any of its products in life support applications where the failure or malfunction of the product can  reasonably be expected to cause failure of the life support system or to significantly affect its safety or effectiveness. Products are not authorized for use in  such applications unless Lumissil Microsystems receives written assurance to its satisfaction, that:  a.) the risk of injury or damage has been minimized;  b.) the user assume all such risks; and  c.) potential liability of Lumissil Microsystems is adequately protected under the circumstances Lumissil Microsystems – www.lumissil.com Rev.A, 06/08/2020 4 IS32LT3125/3125A ABSOLUTE MAXIMUM RATINGS VCC, OUT, EN, UV ISET, FAULTB, CSTOR Operating temperature, TA=TJ Storage temperature range, TSTG Package thermal resistance, junction to ambient (4 layer standard test PCB based on JESD 51-2A), θJA Package thermal resistance, junction to thermal PAD (4 layer standard test PCB based on JESD 51-8), θJP Maximum power dissipation, PDMAX ESD (HBM) ESD (CDM) -0.3V ~ +45V -0.3V ~ +7.0V -40°C ~ +150°C -65°C ~ +150°C 43.3°C/W 1.39°C/W 2.31W ±2kV ±750V Note 2: Stresses beyond those listed under “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 condition beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS TJ = -40°C ~ +125°C, VCC=12V, the detail refer to each condition description. Typical values are at TJ = 25°C. Symbol Parameter Conditions Min. Typ. Max. Unit Power Up Parameter VCC VUVLO VUVLO_HY Supply voltage range VCC under voltage lockout threshold voltage VCC under voltage lockout voltage hysteresis 5 VCC falling 4.2 4.5 VCC supply current RISET=20kΩ, VEN =high, No Fault condition. 2.5 ISD Quiescent supply current In shutdown mode (OUT turned off), VEN = low 0.7 RISET=20kΩ, VEN=high. IS32LT3125 OUT connected to Supply current during LED string GND (in fault master IS32LT3125A mode) short or open 20 RISET=20kΩ, VEN= high, VFAULTB= low (in fault slave mode). tSD EN low time for IC power shutdown tON EN high time for IC power up V 4.8 V 0.15 ICC ISD_FLT 28 40 V 3.5 mA mA 30 40 1 2 1 2 48 55 ms 40 μs IOUT= -100mA, VCC= 12V, VEN= High mA Channel Parameter VISET ISET pin voltage RISET= 20kΩ IOUT Output current (Note 3) RISET= 20kΩ, VHR= 1V Lumissil Microsystems – www.lumissil.com Rev.A, 06/08/2020 1 -106 -100 V -94 mA 5 IS32LT3125/3125A ELECTRICAL CHARACTERISTICS (CONTINUE) TJ = -40°C ~ +125°C, VCC=12V, the detail refer to each condition description. Typical values are at TJ = 25°C. Symbol VHR Parameter Minimum headroom voltage Conditions Min. Typ. Max. VCC – VOUT, IOUT= -250mA 1500 VCC – VOUT, IOUT= -100mA 700 Unit mV IOUT_R Channel output current range RISET= 80kΩ, IOUT=-25mA RISET= 8kΩ, IOUT=-250mA -250 IOUT_L Output limit current RISET=5kΩ -350 ILEAK Channel leakage current VEN=Low, VOUT=0V, VCC=28V Current slew time Enabled by EN pin, current rise/fall between 0%~100% 4 μs Fault deglitch time Fault must be present at least this long to trigger the fault detect 25 μs VFAULTB FAULTB pin voltage Sink current = 20mA 0.2 0.4 V RFAULTB FAULTB pin pull up resistor 200 300 KΩ 2 V tSL -300 -25 mA -260 mA 1 μA Fault Protect Parameter tFD VFAULTB_IH VFAULTB_IL FAULTB pin input high enable threshold FAULTB pin input low disable threshold 0.8 V VSCD OUT pin short to GND threshold Measured at OUT VSCD_HY OUT pin short to GND hysteresis Measured at OUT VOCD OUT pin open threshold Measured at (VCC-VOUT) VOC_HY OUT pin open hysteresis Measured at (VCC-VOUT) 100 ICST CSTOR leakage current VCSTOR = 5.5V 4.6 TSD Thermal shutdown threshold (Note 4) 165 °C THY Over-temperature hysteresis (Note 4) 25 °C EN input voltage threshold Voltage rising 1.0 1.2 1.5 220 150 V mV 300 mV mV 10 μA Logic Input VEN VENHY EN input hysteresis fPWM PWM frequency to EN (Note 4) VUV UV input voltage threshold Voltage rising VUVHY 1.18 1.23 1.28 40 UV input hysteresis 1.18 1.23 40 V mV 1 kHz 1.28 V mV Note 3: Output current accuracy is not intended to be guaranteed at output voltages less than 1.8V. Note 4: Guaranteed by design. Lumissil Microsystems – www.lumissil.com Rev.A, 06/08/2020 6 IS32LT3125/3125A TYPICAL PERFORMANCE CHARACTERISTICS 300 110 105 TJ = -40°C TJ = 25°C 100 TJ = 125°C RISET = 8kΩ VCC = 12V TJ = -40°C 250 Output Current (mA) Output Current (mA) VHR = 2V RISET = 20kΩ 200 150 RISET = 20kΩ 100 95 RISET = 80kΩ 50 90 5 15 25 35 0 45 0 1 2 3 7 8 9 10 9 10 110 125 300 300 RISET = 8kΩ VCC = 12V TJ = 25°C 200 150 RISET = 20kΩ 100 RISET = 80kΩ 50 0 1 2 3 4 5 RISET = 8kΩ VCC = 12V TJ = 125°C 250 Output Current (mA) 250 Output Current (mA) 6 Figure 4 IOUT vs. VHR Figure 3 IOUT vs. VCC 200 150 RISET = 20kΩ 100 RISET = 80kΩ 50 6 7 8 9 0 10 0 1 2 3 6 7 8 330 300 RISET = 8kΩ VCC = 12V VHR = 2V Output Current (mA) 325 200 150 RISET = 20kΩ 100 RISET = 80kΩ 50 0 -40 5 Figure 6 IOUT vs. VHR Figure 5 IOUT vs. VHR 250 4 Headroom Voltage (V) Headroom Voltage (V) Output Current (mA) 5 Headroom Voltage (V) Supply Voltage (V) 0 4 -25 -10 5 20 35 50 VCC = 12V VHR = 2V RISET = 5kΩ 320 315 310 305 65 80 Temperature (°C) Figure 7 IOUT vs. TJ Lumissil Microsystems – www.lumissil.com Rev.A, 06/08/2020 95 110 125 300 -40 -25 -10 5 20 35 50 65 80 95 Temperature (°C) Figure 8 IOUT_L vs. TJ 7 IS32LT3125/3125A 4 0.85 Supply Current (mA) Supply Current (mA) 3.5 0.90 VCC = 12V RISET = 20kΩ EN = High 3 2.5 2 0.80 0.75 0.70 0.65 1.5 1 -40 VCC = 12V EN = Low -25 -10 5 20 35 50 65 80 95 110 0.60 -40 125 -25 -10 5 Temperature (°C) Figure 9 ICC vs. TJ 65 80 95 110 125 80 95 110 125 80 95 110 125 Figure 10 ISD vs. TJ VCC = 12V Fault Slave Mode 29 Supply Current (mA) Supply Current (mA) 50 1 VCC = 12V Fault Master Mode 28 27 0.8 0.6 0.4 0.2 26 -25 -10 5 20 35 50 65 80 95 110 0 -40 125 -25 -10 5 Temperature (°C) 20 35 50 65 Temperature (°C) Figure 11 ISD_FLT vs. TJ For IS32LT3125 Figure 12 ISD_FLT vs. TJ 1.5 1.1 VCC = 12V Fault Master Mode VCC = 12V RISET = 12kΩ 1.2 1.05 VISET (V) Supply Current (mA) 35 Temperature (°C) 30 25 -40 20 0.9 1 0.6 0.95 0.3 0 -40 -25 -10 5 20 35 50 65 80 Temperature (°C) Figure 13 ISD_FLT vs. TJ for IS32LT3125A Lumissil Microsystems – www.lumissil.com Rev.A, 06/08/2020 95 110 125 0.9 -40 -25 -10 5 20 35 50 65 Temperature (°C) Figure 14 VISET vs. TJ 8 IS32LT3125/3125A 4.8 1.25 VCC = 12V 1.24 VCC = 12V VIH 4.75 1.23 4.7 VUVLO (V) VUV (V) 1.22 1.21 1.2 VIL 1.19 VIH 4.65 4.6 4.55 VIL 1.18 4.5 1.17 4.45 1.16 1.15 -40 -25 -10 5 20 35 50 65 80 95 110 4.4 -40 125 -25 -10 Temperature (°C) 20 35 50 65 80 95 110 125 Temperature (°C) Figure 15 VUV vs. TJ Figure 16 VUVLO vs. TJ 1.25 100 VCC = 12V VIH Output Current (mA) 1.21 VIL 1.19 VCC = 12V RISET = 20kΩ PSM Dimming 1kHz TJ = -40°C, 25°C, 125°C 90 1.23 VEN (V) 5 80 70 60 50 40 30 20 1.17 10 1.15 -40 -25 -10 5 20 35 50 65 80 95 110 0 125 0 20 Temperature (°C) Figure 17 VEN vs. TJ 80 100 80 100 Figure 18 PSM Dimming at 1kHz 100 VCC = 12V RISET = 20kΩ PSM Dimming 500Hz TJ = -40°C, 25°C, 125°C 80 70 60 50 40 80 70 60 50 40 30 30 20 20 10 10 0 20 VCC = 12V RISET = 20kΩ PSM Dimming 100Hz TJ = -40°C, 25°C, 125°C 90 Output Current (mA) 90 Output Current (mA) 60 PSM Duty Cycle (%) 100 0 40 40 60 PSM Duty Cycle (%) Figure 19 PSM Dimming at 500Hz Lumissil Microsystems – www.lumissil.com Rev.A, 06/08/2020 80 100 0 0 20 40 60 PSM Duty Cycle (%) Figure 20 PSM Dimming at 100Hz 9 IS32LT3125/3125A 100 100 VCC = 12V RISET = 20kΩ PWM Dimming 1kHz TJ = -40°C, 25°C, 125°C 80 70 60 50 40 80 70 60 50 40 30 30 20 20 10 10 0 0 20 VCC = 12V RISET = 20kΩ PWM Dimming 100Hz TJ = -40°C, 25°C, 125°C 90 Output Current (mA) Output Current (mA) 90 40 60 80 100 0 0 20 40 PWM Duty Cycle (%) VCC = 12V VHR = 2V TA = -40°C VCC = 12V VHR = 2V TA = -40°C VISET 500mV/Div VFAULT 2V/Div VFAULT 2V/Div IOUT 50mA/Div IOUT 50mA/Div Time (1µs/Div) Time (4µs/Div) Figure 23 EN Off VEN 2V/Div 100 Figure 22 PWM Dimming at 100Hz VEN 2V/Div VISET 500mV/Div 80 PWM Duty Cycle (%) Figure 21 PWM Dimming at 1kHz VEN 2V/Div 60 VCC = 12V VHR = 2V TA = 25°C Figure 24 EN On VEN 2V/Div VISET 500mV/Div VISET 500mV/Div VFAULT 2V/Div VFAULT 2V/Div IOUT 50mA/Div IOUT 50mA/Div Time (1µs/Div) Figure 25 EN Off Lumissil Microsystems – www.lumissil.com Rev.A, 06/08/2020 VCC = 12V VHR = 2V TA = 25°C Time (4µs/Div) Figure 26 EN On 10 IS32LT3125/3125A VEN 2V/Div VCC = 12V VHR = 2V TA = 125°C VEN 2V/Div VISET 500mV/Div VISET 500mV/Div VFAULT 2V/Div VFAULT 2V/Div IOUT 50mA/Div IOUT 50mA/Div Time (2µs/Div) Time (4µs/Div) Figure 27 EN Off VEN 2V/Div VCC = 12V VHR = 2V TA = 125°C Figure 28 EN On VEN 2V/Div VISET 500mV/Div VISET 500mV/Div VFAULT 2V/Div VFAULT 2V/Div IOUT 50mA/Div IOUT 50mA/Div Time (20ms/Div) VCC = 12V VHR = 2V TA = 25°C Time (20ms/Div) Figure 29 tSD VEN 2V/Div VCC = 12V VHR = 2V TA = 125°C Figure 30 tSD VCC = 12V VHR = 2V TA = -40°C VISET 500mV/Div VFAULT 2V/Div IOUT 50mA/Div Time (20ms/Div) Figure 31 tSD Lumissil Microsystems – www.lumissil.com Rev.A, 06/08/2020 11 IS32LT3125/3125A FUNCTIONAL BLOCK DIAGRAM Lumissil Microsystems – www.lumissil.com Rev.A, 06/08/2020 12 IS32LT3125/3125A APPLICATION INFORMATION The IS32LT3125/3125A is a single channel linear current driver optimized to drive automotive interior or exterior LED light which can be dimmed via Power Supply Modulation (PSM) or by digitally driving the EN pin. The output current is set by a single reference resistor (RISET) and capable of 250mA. OUTPUT CURRENT SETTING A single resistor (RISET) controls the maximum output current for the channel. The resistor value for a specific current level is calculated using the following Equation (1): RISET 2000  I SET (1) (8kΩ≤RISET≤80kΩ) RISET need to be chosen 1% accuracy resistor with good temperature characteristic to ensure stable output current. The device is protected from an output overcurrent condition caused by a too low value RISET, by internally limiting the maximum current to 300mA (Typ.). If ISET pin is open, the output will be off and FAULTB will be pulled low. I LED  I MAX  DPWM IMAX is computed using Equation (1) and DPWM is the duty cycle. To guarantee a reasonably good dimming effect, recommend PWM frequency in the range of 100Hz ~ 1kHz. Driving the EN pin with a PWM signal can effectively adjust the LED intensity. The PWM signal voltage levels must meet the EN pin input voltage levels, VEN. Pull up to VCC via a 10KΩ resister when EN pin is unused; do not leave it floating. UNDER VOLTAGE PIN OPERATION The IC has an internal VCC UVLO (Under Voltage Lock Out) set at VUVLO. However, it may be desirable to externally set an UVLO to track the number of LED’s used in the string. For PSM dimming application, the higher UVLO will track the PSM off time to a pre-determined VCC level. In addition, it is necessary to prevent false LED open detection due to the LED string losing its headroom voltage, such as when VCC rises up from zero during power up or PSM dimming. The UV pin can be used to set a VCC under voltage lockout threshold via a resistor divider. VBattery 5 POWER SUPPLY MODULATION DIMMING The IS32LT3125/3125A can operate with Power Supply Modulation (PSM) where the device’s power supply is pulse width modulated to achieve LED dimming. The IS32LT3125/3125A stability is not affected by operation with PSM. To get better dimming linearity, the recommended PSM frequency can be in the range of 100Hz to 300Hz, (200Hz Typ.) and input capacitor, CVCC, should be low value (0.1uF typical) to ensure rapid discharge during PSM low period. CSTOR OPERATION To keep the IC operating normally during condition of PSM when VCC goes to zero, CSTOR capacitor provides the keep-alive current needed to power the digital counter and the fault flag circuits. A capacitor value of 2.2µF is recommended. The keep-alive time could be roughly calculated by the following Equation (2): t alive 2.5V  C STOR  I CST (2) EN PIN OPERATION The voltage at the EN pin must be higher than VEN to enable the IC and below (VEN-VENHY) to disable the IC. The EN pin of the IS32LT3125/3125A can accept a PWM signal to implement LED dimming. LED average current may be computed using the following Equation (3). Lumissil Microsystems – www.lumissil.com Rev.A, 06/08/2020 (3) VCC PSM R1 R2 Figure 32 6 UV IS32LT3125 /IS32LT3125A UV Pin Operation This external UVLO threshold voltage can be computed using the following Equation (4): VCC _ UVLO  VUV  R1  R2 R2 (4) Pull up to VCC using a 10kΩ resister when UV pin is unused; do not leave it floating. To prevent false open detection, the external UVLO threshold voltage should be set at Equation (5): VCC _ UVLO  VLED _ MAX  VOCD (5) Where VLED_MAX is the maximum LED string forward voltage on the output channel. OUTPUT STATE DIAGNOSTIC DETECTION AND FAULT IS32LT3125/3125A offers a fault diagnostic function. LED string open/short, output shorted to GND/VCC, 13 IS32LT3125/3125A ISET pin short/open or thermal shutdown will trigger this function. An output shorted to GND or VCC is detected as a fault if the OUT pin voltage drops below the short detect voltage threshold VSCD or VCC to OUT drop voltage is lower than VOCD and remains below the threshold for tFD. Then the channel will change to source a 4mA current for recovery detection. The FAULTB pin will be pulled low and the VCC standby current will increase to ISD_FLT (typical, 30mA for IS32LT3125, 1mA for IS32LT3125A) to indicate the fault condition. This state will recover after the fault condition is removed. If the ISET pin is either shorted or open for tFD deglitch time, the channel will turn off. The FAULTB pin will pull low and the VCC standby current will increase to ISD_FLT (typical, 30mA for IS32LT3125, 1mA for IS32LT3125A) to indicate the fault condition. The state will recover after the fault condition is removed. FAULTB PARALLEL INTERCONNECTION For LED lighting systems which require the complete lighting system be shut down when a fault is detected, the FAULTB pin can be used in a parallel connection with multiple IS32LT3125/3125A devices as shown in Figure 2. A detected fault output by one device (fault master device) will pull low the FAULTB pins of the other parallel connected devices (fault slave devices) and simultaneously turn them off. This satisfies the “One-Fail-All-Fail” operating requirement. For IS32LT3125, only the fault master device has 30mA VCC standby current indication. THERMAL SHUTDOWN Figure 33 OUT Pin Shorted Operation In the event the LED channel is open circuited, the OUT pin voltage will go up close to VCC. If VCC to OUT drop voltage remains below the threshold VOCD for tFD, the channel will change to source a 4mA current for recovery detection. The FAULTB pin will be pulled low and the VCC standby current will increase to ISD_FLT (typical, 30mA for IS32LT3125, 1mA for IS32LT3125A) to indicate the fault condition. The state will recover after the open condition is removed. To protect the IC from damage due to high power dissipation, the temperature of the die is monitored. In the event that the die temperature exceeds 165°C, the device will go into shutdown mode. The channel (OUT) will turn off. The FAULTB pin will pull low and the VCC standby current will increase to ISD_FLT (typical, 30mA for IS32LT3125, 1mA for IS32LT3125A) to indicate the fault condition. At this point, the IC begins to cool off. Any attempt to enable the channel back to the source condition before the IC cooled to TJ