| Driver | Buck |
|---|---|
| Status | Prod |
| Vin(V) | 4.5~38 |
| Dimming | PWM |
| Document | Eval Board |
| Key Feature | 1.5-Ampere PWM dimmable constant-current buck LED driver with output fault report/protect, 2uA shutdown, spread spectrum |
| Power Transistor | Built-in |
| Pkg-Pin(mm) | SOP-8-EP |
| Product Family | 32 = Automotive Analog and Mixed Signal |
| Part Number | 3951 = 3951 |
| Product Type | LT = Lighting LED Driver |
| Temperature Grade | A3 = Automotive temp. (-40°C to 125°C) |
| Package option | TR = Tape & Reel |
| Solder Type | L = Lead-free (RoHS Compliant) |
| Package Type | GR = SOP |
| Outpack | Tape on Reel |
The IS32LT3951 is a DC-to-DC switching converter that integrates an N-channel MOSFET to operate in a buck configuration. The device can operate from a wide input voltage between 4.5V and 38V and provides a constant current of up to 1.5A for driving a single LED or multiple series connected LEDs. The external resistor, RISET, is used to set a constant LED output current, while allowing the output voltage to be automatically adjusted for a variety of LED configurations. The IS32LT3951 operates in a fixed frequency mode during switching. There is an external resistor connected between the VCC and TON pins used to configure the on-time (switching frequency). The switching frequency is dithered for spread spectrum operation which will spread the electromagnetic energy into a wider frequency band. This function is helpful for optimizing EMI performance. A logic input PWM signal applied to the enable (EN) pin will adjust the average LED current. The LED brightness is proportional to the duty cycle of the PWM signal. True average output current operation is achieved with fast transient response by using cycle-by-cycle, controlled on-time method. The IS32LT3951 is available in an SOP-8-EP package with an exposed pad for enhanced thermal dissipation. It operates from 4.5V to 38V over the temperature range of -40°C to +125°C.