LT8610 查看數據表（PDF） - Linear Technology

零件编号

产品描述 (功能)

生产厂家

LT8610

42V, 2.5A Synchronous Step-Down Regulator with 2.5µA Quiescent Current

Linear Technology 

LT8610

TYPICAL PERFORMANCE CHARACTERISTICS

Transient Response

Start-Up Dropout Performance

Start-Up Dropout Performance

ILOAD

1A/DIV

VOUT

200mV/DIV

50µs/DIV

50mA TO 1A TRANSIENT

12VIN, 5VOUT

COUT = 47µF

8610 G36

VIN

2V/DIV

VOUT

2V/DIV

VIN

VOUT

100ms/DIV

2.5Ω LOAD

(2A IN REGULATION)

8610 G37

VIN

2V/DIV

VOUT

2V/DIV

VIN

VOUT

100ms/DIV

20Ω LOAD

(250mA IN REGULATION)

8610 G38

PIN FUNCTIONS

SYNC (Pin 1): External Clock Synchronization Input.

Ground this pin for low ripple Burst Mode operation at low

output loads. Tie to a clock source for synchronization to

an external frequency. Apply a DC voltage of 3V or higher

or tie to INTVCC for pulse-skipping mode. When in pulse-

skipping mode, the IQ will increase to several hundred µA.

Do not float this pin.

TR/SS (Pin 2): Output Tracking and Soft-Start Pin. This

pin allows user control of output voltage ramp rate during

start-up. A TR/SS voltage below 0.97V forces the LT8610

to regulate the FB pin to equal the TR/SS pin voltage. When

TR/SS is above 0.97V, the tracking function is disabled

and the internal reference resumes control of the error

amplifier. An internal 2.2μA pull-up current from INTVCC

on this pin allows a capacitor to program output voltage

slew rate. This pin is pulled to ground with an internal 230Ω

MOSFET during shutdown and fault conditions; use a series

resistor if driving from a low impedance output. This pin

may be left floating if the tracking function is not needed.

RT (Pin 3): A resistor is tied between RT and ground to

set the switching frequency.

EN/UV (Pin 4): The LT8610 is shut down when this pin

is low and active when this pin is high. The hysteretic

threshold voltage is 1.00V going up and 0.96V going

down. Tie to VIN if the shutdown feature is not used. An

external resistor divider from VIN can be used to program

a VIN threshold below which the LT8610 will shut down.

VIN (Pins 5, 6): The VIN pins supply current to the LT8610

internal circuitry and to the internal topside power switch.

These pins must be tied together and be locally bypassed.

Be sure to place the positive terminal of the input capaci-

tor as close as possible to the VIN pins, and the negative

capacitor terminal as close as possible to the PGND pins.

PGND (Pins 7, 8): Power Switch Ground. These pins are

the return path of the internal bottom-side power switch

and must be tied together. Place the negative terminal of

the input capacitor as close to the PGND pins as possible.

SW (Pins 9, 10, 11): The SW pins are the outputs of the

internal power switches. Tie these pins together and con-

nect them to the inductor and boost capacitor. This node

should be kept small on the PCB for good performance.

BST (Pin 12): This pin is used to provide a drive voltage,

higher than the input voltage, to the topside power switch.

Place a 0.1µF boost capacitor as close as possible to the IC.

INTVCC (Pin 13): Internal 3.4V Regulator Bypass Pin.

The internal power drivers and control circuits are pow-

ered from this voltage. INTVCC maximum output cur-

rent is 20mA. Do not load the INTVCC pin with external

circuitry. INTVCC current will be supplied from BIAS if

VBIAS > 3.1V, otherwise current will be drawn from VIN.

Voltage on INTVCC will vary between 2.8V and 3.4V when

VBIAS is between 3.0V and 3.6V. Decouple this pin to power

ground with at least a 1μF low ESR ceramic capacitor

placed close to the IC.

8610fa

8

For more information www.linear.com/LT8610

Share Link: