LT3492 데이터 시트보기 (PDF) - Linear Technology

부품명

상세내역

제조사

LT3492

Triple Output LED Driver with 3000:1 PWM Dimming

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 floating.

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 floating.

GND: Signal Ground and Power Ground. Solder exposed

pad directly to ground plane.

ISN1, ISN2, ISN3: Noninverting Input of Current Sense

Error Amplifier. Connect directly to LED current sense

resistor terminal for current sensing of the respective

converter.

ISP1, ISP2, ISP3: Inverting Input of Current Sense Error

Amplifier. 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

quiescent supply current and causes the VC pin for that

converter to become high impedance. PWM pin must not

be left floating; tie to VREF if not used.

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-

fier 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.

VC1, VC2, VC3: Error Amplifier Compensation Pins. Connect

a series RC from these pins to GND.

VIN: Input Supply Pin. Must be locally bypassed. Powers

the internal control circuitry.

VREF: Reference Output Pin. Can supply up to 200μA. The

nominal Output Voltage is 2V.

3492f

6

Share Link: