LT3492 LINER [Linear Technology], LT3492 Datasheet - Page 6

• Manufacturer Part Number: LT3492
• Description: Triple Output LED Driver with 3000:1 PWM Dimming
• Manufacturer: LINER [Linear Technology]

LT3492
PIN FUNCTIONS
CTRL1, CTRL2, CTRL3: LED Current Adjustment Pins. Sets
voltage across external sense resistor between ISP and ISN
pins of the respective converter. Setting CTRL voltage to
be less than 1V will control the current sense voltage to be
one-tenth of CTRL voltage. If CTRL voltage is higher than
1V, the default current sense voltage is 100mV. The CTRL
pin must not be left fl oating.
FADJ: Switching Frequency Adjustment Pin. Setting FADJ
voltage to be less than 1V will adjust switching frequency
up to 2.1MHz. If FADJ voltage is higher than 1V, the default
switching frequency is 2.1MHz. The FADJ pin must not
be left fl oating.
GND: Signal Ground and Power Ground. Solder exposed
pad directly to ground plane.
ISN1, ISN2, ISN3: Noninverting Input of Current Sense
Error Amplifi er. Connect directly to LED current sense
resistor terminal for current sensing of the respective
converter.
ISP1, ISP2, ISP3: Inverting Input of Current Sense Error
Amplifi er. Connect directly to other terminal of LED current
sense resistor terminal of the respective converter.
OVP1, OVP2, OVP3: Open LED Protection Pins. A voltage
higher than 1V on OVP turns off the internal main switch
of the respective converter. Tie to ground if not used.
PWM1, PWM2, PWM3: Pulse Width Modulated Input.
Signal low turns off the respective converter, reduces
6
quiescent supply current and causes the V
converter to become high impedance. PWM pin must not
be left fl oating; tie to V
SHDN: Shutdown Pin. Used to shut down the switching
regulator and the internal bias circuits for all three convert-
ers. Tie to 1.5V or greater to enable the device. Tie below
0.4V to turn off the device.
SW1, SW2, SW3: Switch Pins. Collector of the internal
NPN power switch of the respective converter. Connect
to external inductor and anode of external Schottky recti-
fi er of the respective converter. Minimize the metal trace
area connected to this pin to minimize electromagnetic
interference.
TG1, TG2, TG3: The Gate Driver Output Pin for Disconnnect
P-Channel MOSFET. One for each converter. When the
PWM pin is low, the TG pin pulls up to ISP to turn off the
external MOSFET. When the PWM pin is high, the external
MOSFET turns on. ISPn-TGn is limited to 6.5V to protect
the MOSFET. Leave open if the external MOSFET is not
used.
V
a series RC from these pins to GND.
V
the internal control circuitry.
V
nominal Output Voltage is 2V.
C1
IN
REF
: Input Supply Pin. Must be locally bypassed. Powers
, V
: Reference Output Pin. Can supply up to 200μA. The
C2
, V
C3
: Error Amplifi er Compensation Pins. Connect
REF
if not used.
C
pin for that
3492f