Datasheet LT3492 (Analog Devices) - 7
| Fabricante | Analog Devices |
| Descripción | Triple Output LED Driver with 3000:1 PWM Dimming |
| Páginas / Página | 22 / 7 — PIN FUNCTIONS. CTRL1, CTRL2, CTRL3:. SHDN:. FADJ:. SW1, SW2, SW3:. GND:. … |
| Formato / tamaño de archivo | PDF / 338 Kb |
| Idioma del documento | Inglés |
PIN FUNCTIONS. CTRL1, CTRL2, CTRL3:. SHDN:. FADJ:. SW1, SW2, SW3:. GND:. TG1, TG2, TG3:. ISN1, ISN2, ISN3:. ISP1, ISP2, ISP3:
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LT3492
PIN FUNCTIONS CTRL1, CTRL2, CTRL3:
LED Current Adjustment Pins. Sets quiescent supply current and causes the VC pin for that voltage across external sense resistor between ISP and ISN converter to become high impedance. PWM pin must not pins of the respective converter. Setting CTRL voltage to be left fl oating; tie to VREF if not used. be less than 1V will control the current sense voltage to be
SHDN:
Shutdown Pin. Used to shut down the switching one-tenth of CTRL voltage. If CTRL voltage is higher than regulator and the internal bias circuits for all three convert- 1V, the default current sense voltage is 100mV. The CTRL ers. Tie to 1.5V or greater to enable the device. Tie below pin must not be left fl oating. 0.4V to turn off the device.
FADJ:
Switching Frequency Adjustment Pin. Setting FADJ
SW1, SW2, SW3:
Switch Pins. Collector of the internal voltage to be less than 1V will adjust switching frequency NPN power switch of the respective converter. Connect up to 2.1MHz. If FADJ voltage is higher than 1V, the default to external inductor and anode of external Schottky recti- switching frequency is 2.1MHz. The FADJ pin must not fi er of the respective converter. Minimize the metal trace be left fl oating. area connected to this pin to minimize electromagnetic
GND:
Signal Ground and Power Ground. Solder exposed interference. pad directly to ground plane.
TG1, TG2, TG3:
The Gate Driver Output Pin for Discon-
ISN1, ISN2, ISN3:
Noninverting Input of Current Sense nect P-Channel MOSFET. One for each converter. When Error Amplifi er. Connect directly to LED current sense the PWM pin is low, the TG pin pulls up to ISP to turn resistor terminal for current sensing of the respective off the external MOSFET. When the PWM pin is high, the converter. external MOSFET turns on. ISPn-TGn is limited to 6.5V to protect the MOSFET. Leave open if the external MOSFET
ISP1, ISP2, ISP3:
Inverting Input of Current Sense Error is not used. Amplifi er. Connect directly to other terminal of LED current sense resistor terminal of the respective converter.
VC1, VC2, VC3:
Error Amplifi er Compensation Pins. Connect a series RC from these pins to GND.
OVP1, OVP2, OVP3:
Open LED Protection Pins. A voltage higher than 1V on OVP turns off the internal main switch
VIN:
Input Supply Pin. Must be locally bypassed. Powers of the respective converter. Tie to ground if not used. the internal control circuitry.
PWM1, PWM2, PWM3:
Pulse Width Modulated Input.
VREF:
Reference Output Pin. Can supply up to 200μA. The Signal low turns off the respective converter, reduces nominal Output Voltage is 2V. 3492fa 7
PIN FUNCTIONS CTRL1, CTRL2, CTRL3:
LED Current Adjustment Pins. Sets quiescent supply current and causes the VC pin for that voltage across external sense resistor between ISP and ISN converter to become high impedance. PWM pin must not pins of the respective converter. Setting CTRL voltage to be left fl oating; tie to VREF if not used. be less than 1V will control the current sense voltage to be
SHDN:
Shutdown Pin. Used to shut down the switching one-tenth of CTRL voltage. If CTRL voltage is higher than regulator and the internal bias circuits for all three convert- 1V, the default current sense voltage is 100mV. The CTRL ers. Tie to 1.5V or greater to enable the device. Tie below pin must not be left fl oating. 0.4V to turn off the device.
FADJ:
Switching Frequency Adjustment Pin. Setting FADJ
SW1, SW2, SW3:
Switch Pins. Collector of the internal voltage to be less than 1V will adjust switching frequency NPN power switch of the respective converter. Connect up to 2.1MHz. If FADJ voltage is higher than 1V, the default to external inductor and anode of external Schottky recti- switching frequency is 2.1MHz. The FADJ pin must not fi er of the respective converter. Minimize the metal trace be left fl oating. area connected to this pin to minimize electromagnetic
GND:
Signal Ground and Power Ground. Solder exposed interference. pad directly to ground plane.
TG1, TG2, TG3:
The Gate Driver Output Pin for Discon-
ISN1, ISN2, ISN3:
Noninverting Input of Current Sense nect P-Channel MOSFET. One for each converter. When Error Amplifi er. Connect directly to LED current sense the PWM pin is low, the TG pin pulls up to ISP to turn resistor terminal for current sensing of the respective off the external MOSFET. When the PWM pin is high, the converter. external MOSFET turns on. ISPn-TGn is limited to 6.5V to protect the MOSFET. Leave open if the external MOSFET
ISP1, ISP2, ISP3:
Inverting Input of Current Sense Error is not used. Amplifi er. Connect directly to other terminal of LED current sense resistor terminal of the respective converter.
VC1, VC2, VC3:
Error Amplifi er Compensation Pins. Connect a series RC from these pins to GND.
OVP1, OVP2, OVP3:
Open LED Protection Pins. A voltage higher than 1V on OVP turns off the internal main switch
VIN:
Input Supply Pin. Must be locally bypassed. Powers of the respective converter. Tie to ground if not used. the internal control circuitry.
PWM1, PWM2, PWM3:
Pulse Width Modulated Input.
VREF:
Reference Output Pin. Can supply up to 200μA. The Signal low turns off the respective converter, reduces nominal Output Voltage is 2V. 3492fa 7