ISSI IS32LT3954 | Demoboard IS31LT3954_IS32LT3954 DEMO BOARD GUIDE

Description

The IS31LT3954_IS32LT3954 is a DC-to-DC switching converter, which integrate an N-channel MOSFET to operate in a buck configuration. The device supply a wide input voltage between 4.5V and 38V and provides a constant current of up to 3A for driving a single LED or multiple series connected LEDs.The external resistor, RSET, is used to adjust LED output current, which allowing the output voltage to be automatically adjusted for a variety of LED configurations.The IS31LT3954_IS32LT3954 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 feature to spread the electromagnetic emitting energy into a wider frequency band. It is helpful to optimize the EMI performance.A logic input PWM signal to the enable (EN) pin is applied to adjust the LED current. The brightness of LED 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.IS31LT3954_IS32LT3954 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.

Features

• Wide input voltage supply from 4.5V to 38V
• Withstand 40V load dump
• ±5% true average output current control
• 3A maximum output over operating temperature range
• Cycle-by-cycle current limit
• Integrated high-side MOSFET switch
• Dimming via direct logic input or power supply voltage
• Internal control loop compensation
• Under-voltage lockout (UVLO) and thermal shutdown protection
• 2μA low power shutdown
• Spread spectrum to optimize EMI
• Robust fault protection and reporting function:
• Pin-to-GND short
• Component open/short faults
• Adjacent pin-to-pin short
• LED open/short
• AEC-Q100 qualification
• IS32LT3954 only

Typical applications

• Automotive and avionic lighting, Daytime running lights, Turn/stop lights, Front and rear fog lights, Matrix headlight, Motorcycle headlight

More information

• Datasheet
• IC product information