IS32LT3140A SINGLE CHANNEL 450mA LED DRIVER WITH THERMAL SHUNT RESISTOR AND SINGLE LED SHORT DETECTION June 2021 GENERAL DESCRIPTION FEATURES The IS32LT3140A is an automotive-grade high-side Wide input voltage range, 4.5V to 40V programmable current regulator consisting of a single Single-channel sources up to 450mA output channel capable of 450mA. An external resistor High-side external resister sets source current sets the current level for the single-channel current 8% current accuracy over -40C ~ +150C source. An optional thermal shunt resistor can be used Low headroom voltage, max 700mV at 150mA to significantly optimize IC power dissipation. It features Low operating current of 350A and 5A in an EN pin to enable or shutdown the device. It supports shutdown either PWM dimming via a PWM pin or power supply modulation (PSM). A resistor divider circuit can be used Optional thermal shunt resistor to optimize IC on the UV pin to set an external VCC under-voltage power dissipation lockout threshold for LED string open and single LED Support for both PWM or PSM dimming short fault detection. In addition, the IS32LT3140A Programmable VIN under-voltage lockout at PWM integrates fault protection for a single LED short, LED pin string open/short, output overcurrent (not reported), Fault protection with open-drain flag output: and over-temperature condition for robust operation. - Selectable fault actions Detection of these failures is reported by the FAULTB - Single LED short pin. When a fault is detected the device will disable - LED string open/short itself and output an active low open drain signal. - Output overcurrent (not reported) Multiple devices can have their FAULTB pins connected to create a one-fail-all-fail condition. - Thermal shutdown Shared fault flag for multiple device operation to The IS32LT3140A is targeted at the automotive market comply with one-fail-all-fail function with end applications to include interior and exterior AEC-Q100 Qualified lighting. For 12V automotive applications, the low dropout driver can support one to several LEDs on the Operating temperature range from -40C ~ +150C output channel. The device is offered in a small APPLICATIONS thermally enhanced eTSSOP-14 package. Automotive interior/exterior lighting: - Turn signal light - Rear lamp - Dome light TYPICAL APPLICATION CIRCUIT R ISET V Battery D 1 14 13 VIN VICC Optional R 10k UV1 Thermal Shunt C R VIN P Resistor 1 11 EN OUT 2 R R UV R PWM1 UV2 SD1 9 SDH IS32LT3140A 4 R SD2 PWM R PWM2 V IN 8 10k SDL 5 SMODE 6 FAULTB 3 7 FMODE GND Figure 1 Typical Application Circuit (PSM Dimming Or Non-Dimming Applications) Lumissil Microsystems www.lumissil.com 1 Rev. A, 02/08/2021 IS32LT3140A R ISET V Battery D 1 14 13 VIN VICC 10k C VIN 1 11 EN OUT R UV1 2 UV R SD1 R UV2 9 SDH R SD2 IS32LT3140A 4 PWM Input PWM V IN 8 10k SDL 5 SMODE 6 FAULTB 3 7 FMODE GND Figure 2 Typical Application Circuit with PWM Dimming Note 1: For PSM dimming application, a high C capacitor value will affect the dimming accuracy. To get better dimming performance, VIN recommend a value of 0.1F. If no PSM dimming requirement, C can be a larger value. VIN Note 2: The thermal shunt resistor R is only available for applications without EN shutdown, PWM dimming or one fail all fail mode fault P protection. Note 3: The current sense resistor R must be placed as close as possible to VIN and VICC pins on the PCB layout to avoid noise interference. ISET Lumissil Microsystems www.lumissil.com 2 Rev. A, 02/08/2021