IS32LT3953 Datasheet, PDF (1/10 Pages) Integrated Silicon Solution, Inc – CONSTANT-CURRENT 3-AMPERE PWM DIMMABLE

IS32LT3953
CONSTANT-CURRENT 3-AMPERE PWM DIMMABLE
BUCK REGULATOR LED DRIVER
Advanced Information
December 2013
GENERAL DESCRIPTION
The IS32LT3953 is a DC-to-DC switching converter
with an integrated N-channel MOSFET operating in a
buck configuration. The device is connected to a
voltage higher than the LED voltage; between 6V and
48V and provides a constant current of up to 3.0A for
driving a single LED or multiple series connected
LEDs.
The LED output current is set by an external current
sense resistor, allowing the output voltage to be
automatically adjusted for a variety of LED
configurations.
The IS32LT3953 operates in a fixed frequency mode
during switching. The on-time (switching frequency) is
programmed using an external resistor connected
between the VIN and TON pins.
LED dimming is accomplished by applying a logic
input PWM (pulse-width-modulation) signal to the
enable (EN) pin. The resulting LED brightness is
proportional to the duty cycle of the PWM signal.
True average current is output using cycle-by-cycle,
controlled on-time method.
The IS32LT3953 is offered in an SOP-8-EP package
with an exposed pad for enhanced thermal dissipation.
The operating temperature range is from -40°C to
+125°C.
FEATURES
 Supply voltage 6V ~ 48V
 True average output current control
 3.0A maximum output over operating temperature
range
 Cycle-by-cycle current limit
 Integrated MOSFET switch
 Dimming via direct logic input or power supply
voltage
 Internal control loop compensation
 Under-voltage lockout (UVLO) and thermal
shutdown protection
 Low power shutdown (1μA typical)
 Robust protection against:
-Adjacent pin-to-pin short
-Pin-to-GND short
-Component open/short faults
 Automotive AEC-Q100 Qualified (Pending)
APPLICATIONS
 Automotive and avionic lighting
 Daytime running lights
 Front and rear fog lights
 Turn/stop lights
 Map light
 Dimmable interior lights
TYPICAL APPLICATION CIRCUIT
Figure 1 Typical Application Circuit
Integrated Silicon Solution, Inc. – www.issi.com
1
Rev. 00A, 11/29/2013