LT3782AIFE(RevC) Ver la hoja de datos (PDF) - Linear Technology

Número de pieza

componentes Descripción

Lista de partido

LT3782AIFE
(Rev.:RevC)

2-Phase Step-Up DC/DC Controller

Linear Technology 

LT3782A

Pin Functions (FE/UFD)

SGATE2 (Pin 1/Pin 26): Second Phase Synchronous Drive

Signal. An external driver buffer is needed to drive the top

synchronous power FET.

SGATE1 (Pin 2/Pin 27): First Phase Synchronous Drive

Signal. An external driver buffer is needed to drive the top

synchronous power FET.

GND (Pin 4, Exposed Pad Pin 29/Pin 28, Exposed Pad

Pin 29): Ground. Solder the exposed pad to the PCB

ground plane for rated thermal performance. The exposed

pad should be connected to the GND pin as close to the

IC as possible.

SYNC (Pin 5/Pin 1): Synchronization Input. The pulse

width can range from 10% to 70%. Note that the operating

frequency is half of the sync frequency.

DELAY (Pin 6/Pin 2): When synchronous drivers are used,

the programmable delay that delays BGATE turns on after

SGATE turns off.

DCL (Pin 7/Pin 3): This pin programs the limit of the

maximum duty cycle. When connected to VRSET, it oper-

ates at natural maximum duty cycle, approximately 90%.

SENSE1+ (Pin 8/Pin 4): First Phase Current Sense Amplifier

Positive Input. An RC filter is required across the current

sense resistor. Current limit threshold is set at 63mV.

SENSE1– (Pin 9/Pin 5): First Phase Current Sense Ampli-

fier Negative Input.

SLOPE (Pin 10/Pin 6): A resistor from SLOPE to GND

increases the internal current mode PWM slope com-

pensation.

RSET (Pin 11/Pin 7): A resistor from RSET to GND sets the

oscillator charging current and the operating frequency.

SENSE2– (Pin 12/Pin 8): Second Phase Current Sense

Amplifier Negative Input.

SENSE2+ (Pin 13/Pin 10): Second Phase Current Sense

Amplifier Positive Input. An RC filter is required across

the current sense resistor. Current limit threshold is set

at 63mV.

SS (Pin 14/Pin 11): Soft-Start. A capacitor on this pin sets

the output ramp up rate. The typical time for SS to reach

the programmed level is (C • 2.44V)/10µA.

VC (Pin 15/Pin 12): The output of the gm error amplifier and

the control signal of the current loop of the current-mode

PWM. Switching starts at 0.7V, and higher VC voltages

corresponds to higher inductor current.

FB (Pin 16/Pin 13): Error Amplifier Inverting Input. A

resistor divider to this pin sets the output voltage.

RUN (Pin 17/Pin 14): LT3782A goes into shutdown mode

when VRUN is below 2.3V and goes to low bias current

shutdown mode when VRUN is below 0.3V.

VEE2 (Pin 19/Pin 16): Gate Driver BGATE2 Ground. This

pin should be connected to ground as close to the IC as

possible.

BGATE2 (Pin 20/Pin 17): Second Phase MOSFET Driver.

GBIAS2 (Pin 21/Pin 18): Bias for Gate Driver BGATE2.

Should be connected to GBIAS or an external power supply

between 12V to 14V.

GBIAS1 (Pin 22/Pin 21): Bias for Gate Driver BGATE1.

Should be connected to GBIAS2.

BGATE1 (Pin 23/Pin 22): First Phase MOSFET Driver.

VEE1 (Pin 24/Pin 23): Gate Driver BGATE1 Ground. This

pin should be connected to ground as close to the IC as

possible.

VCC (Pin 27/Pin 24): Chip Power Supply. Good supply

bypassing is required.

GBIAS (Pin 28/Pin 25): Internal 11V regulator output for

biasing internal circuitry. Should be connected to GBIAS1

and GBIAS2. A bypass low ESR capacitor of 2µF or larger

is needed and should be connected directly to the pin to

minimize parasitic impedance.

NC (Pins 3, 18, 25, 26/Pins 9, 15, 19, 20): Not Connected.

Can be connected to GND.

3782afc

6

For more information www.linear.com/LT3782A

Share Link: