LTC3787HGN-TRPBF 查看數據表（PDF） - Linear Technology

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LTC3787HGN-TRPBF

PolyPhase Synchronous Boost Controller

Linear Technology 

LTC3787

PIN FUNCTIONS (QFN/SSOP)

SS (Pin 7/Pin 10): Output Soft-Start Input. A capacitor to

ground at this pin sets the ramp rate of the output voltage

during start-up.

SENSE2– , SENSE1– (Pin 8, Pin 28/Pin 11, Pin 3): Nega-

tive Current Sense Comparator Input. The (–) input to the

current comparator is normally connected to the negative

terminal of a current sense resistor connected in series

with the inductor.

SENSE2+, SENSE1+ (Pin 9, Pin 27/Pin 12, Pin 2): Posi-

tive Current Sense Comparator Input. The (+) input to the

current comparator is normally connected to the positive

terminal of a current sense resistor. The current sense resis-

tor is normally placed at the input of the boost controller in

series with the inductor. This pin also supplies power to the

current comparator. The common mode voltage range on

SENSE+ and SENSE– pins is 2.5V to 38V (40V abs max).

VFB (Pin 10/Pin 13): Error Amplifier Feedback Input. This

pin receives the remotely sensed feedback voltage from

an external resistive divider connected across the output.

ITH (Pin 11/Pin 14): Current Control Threshold and Error

Amplifier Compensation Point. The voltage on this pin sets

the current trip threshold.

NC (Pin 12/Pin 15): No Connect.

SW2, SW1 (Pin 13, Pin 24/Pin 16, Pin 27): Switch Node.

Connect to the source of the synchronous N-channel

MOSFET, the drain of the main N-channel MOSFET and

the inductor.

TG2, TG1 (Pin 14, Pin 23/Pin 17, Pin 26): Top Gate. Con-

nect to the gate of the synchronous N-channel MOSFET.

BOOST2, BOOST1 (Pin 15, Pin 22/Pin 18, Pin 25): Float-

ing power supply for the synchronous N-channel MOSFET.

Bypass to SW with a capacitor and supply with a Schottky

diode connected to INTVCC.

PGND (Pin 19/Pin 22): Driver Power Ground. Connects

to the sources of bottom (main) N-channel MOSFETs and

the (–) terminal(s) of CIN and COUT.

BG2, BG1 (Pin 16, Pin 21/Pin 19, Pin 24): Bottom Gate.

Connect to the gate of the main N-channel MOSFET.

INTVCC (Pin 17/Pin 20): Output of Internal 5.4V LDO.

Power supply for control circuits and gate drivers. De-

couple this pin to GND with a minimum 4.7μF low ESR

ceramic capacitor.

EXTVCC (Pin 18/Pin 21): External Power Input. When this

pin is between 4.8V and 6V, an internal switch bypasses

the internal regulator and supply power to INTVCC directly

from EXTVCC. Do not float this pin. It can be connected to

ground when not used.

VBIAS (Pin 20/Pin 23): Main Supply Pin. It is normally

tied to the input supply VIN or to the output of the boost

converter. A bypass capacitor should be tied between this

pin and the signal ground pin. The operating voltage range

on this pin is 4.5V to 38V (40V abs max).

PGOOD (Pin 25/Pin 28): Power Good Indicator. Open-drain

logic output that is pulled to ground when the output volt-

age is more than ±10 % away from the regulated output

voltage. To avoid false trips the output voltage must be

outside the range for 25μs before this output is activated.

ILIM (Pin 26/Pin 1): Current Comparator Sense Voltage

Range Input. This pin is used to set the peak current

sense voltage in the current comparator. Connect this pin

to SGND, open, and INTVCC to set the peak current sense

voltage to 50mV, 75mV and 100mV, respectively.

GND (Exposed Pad Pin 29) UFD Package: Ground. Must

be soldered to the PCB for rated thermal performance.

3787fc

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