LTM4642 datasheet(8/32 Pages) LINER

8 / 32 page

LTM4642

4642fb

For more information www.linear.com/LTM4642

pin FuncTions

GND (A4-A7, C2, D1, D5, E1, E5, E7, F7, H4-H7): Power

ground pins for both input and output returns.

PHASMD (B4): Phase Mode Selection Pin for Program-

ming Clock Out Phase. See Electrical Characteristics and

Applications Information sections.

MODE/PLLIN(C3):ModeSelectionorExternalSynchroni-

zation Pin. Tying this pin to SGND enables discontinuous

mode. Tying this pin to INTVCC enables forced continuous

operation. A clock on the pin will force the controller into

the continuous mode of operation and synchronize the

internal oscillator. The suitable synchronizable frequency

range is 600kHz to 1400kHz subject to inductor ripple

current limits described in the FREQ/PLLFLTR pin section.

The external clock input high threshold is 2V, while the

input low threshold is 0.5V.

CPWR (C7): This pin is the main input power to the control

IC. This pin normally connects to the input source directly.

This pin can be biased at a voltage greater than 4.5V to

allow the VIN1andVIN2tooperatedownto2.375Vinputfor

applications that operate at 2.5V or 3.3V input. If the bias

is less than or equal to 5.3V, connect DRVCC to this pin.

SGND (D2, E2): Signal Ground Pins. Return ground path

for all analog and low power circuitry. Tie a single connec-

tion to PGND in the application. See the Recommended

Layout section.

CLKOUT (D4): Clock Out for Synchronizing Other Regula-

tors to the Common Clock. Used for multiphase applica-

tions. See Applications Information section.

EXTVCC (D6): External Power Input to Controller. When

EXTVCC is higher than 4.7V, the internal 5.3V regulator is

disabledandtheexternalsourcesuppliescurrenttoreduce

the power dissipation in the module. This will improve the

efficiency more at high input voltages.

INTVCC (D7): This pin powers the internal control circuits.

Tie this pin to DRVCCwitha2.2Ωresistor.Thispinrequires

a few milliamps.

PACKAGE ROW AND COLUMN LABELING MAY VARY

AMONG µModule PRODUCTS. REVIEW EACH PACKAGE

LAYOUT CAREFULLY.

COMP1, COMP2 (E3, D3): Current Control Threshold and

Error Amplifier Compensation Point. The module has been

internally compensated for all I/O ranges.

FREQ (E4): Frequency Selection Pin. Tie a resistor from

this pin to SGND to set the frequency of operation between

600kHz to 1.4MHz for the specific output voltages. For

3.3Vinputapplications,650kHzisanoptimizedfrequency.

For 5V to 20V input applications, the optimized operating

frequency for the output voltage is as follows: 0.8V to 1.2V

(650kHz), 1.5V to 1.8V (800kHz), 2.0V to 5V (1.2MHz), 5V

from 20V input (1.4MHz). The resistor equation:

RFREQ kΩ

( )=

41550

FREQ kHz

(

)

– 2.2

DRVCC (E6): This pin is the LDO 5.3V regulator output

used to power the internal control circuits and MOSFET

drivers.Thispinneedsa4.7µFceramicdecouplingcapaci-

tor to GND. For input voltages less than or equal to 5.3V,

connect this pin directly to the input voltage.

VOUTS1 (F2): Output Voltage Sense Point for Channel 1

Remote Sensing. This pin has a 49.9Ω resistor connected

to VOUT1. This pin can be connected at the load point for

accurate remote sensing.

VOUTS–(F3):RemoteGroundSensePin.Connectatremote

ground point.

VFB1, VFB2 (F4, C4): The negative input of the error

amplifier. Internally, this pin is connected to VOUT with

a 60.4k precision resistor. Different output voltages can

be programmed with an additional resistor between VFB

and SGND pins. See the Applications Information section

for details.

TRACK/SS1,TRACK/SS2(F5,C5):OutputVoltageTracking

and Soft-Start Pins. Internal soft-start currents of 1.0µA

charge the soft-start capacitors. See the Applications

Information section to use the tracking function.

PGOOD1, PGOOD2 (F6, C6): Output Voltage Power Good

Indicator. Open-drain logic output that is pulled to ground

when the output voltage is not within ±7.5% of the regula-

tion point. In single output parallel operation when VFB2 is

tied to INTVCC, the PGOOD2 pin is not to be used.

LTM4642 Arkusz danych(PDF) 8 Page - Linear Technology

LTM4642 Arkusz danych(HTML) 8 Page - Linear Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32

Arkusz danych Pobierz

Link URL