LTM8045 datasheet(8/20 Pages) LINER

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LTM8049

8049fa

For more information www.linear.com/LTM8049

PIN FUNCTIONS

FBX1, FBX2 (Pins C1, J1): If configured as a SEPIC, the

LTM8049 regulates its FBX pin to 1.204V. Apply a resis-

tor between FBX and VOUTP. Its value should be RFB =

[(VOUTP – 1.204)/0.0833]k. If the LTM8049 is configured

as an inverting converter, the LTM8049 regulates the FBX

pin to 7mV. Apply a resistor between FBX and VOUTN of

value RFB = [(|VOUTN| + 0.007)/0.0833]k. The LTM8049

features frequency foldback to protect the power switches

during a fault or output current overload. During start-up,

frequency foldback also limits the current the LTM8049

delivers to the load. The user must evaluate the start-up

behavior of the LTM8049 to ensure that it properly pow-

ers up the load.

PG1, PG2 (Pins D6, H6): These active high pins indicates

that the FBn pin voltage for the corresponding channel

is within 4% of its regulation voltage These open drain

outputs requires a pull-up resistor to indicate power good.

Also, the status of these pins is valid only when RUN >

1.4V and VIN > 2.6V.

CLKOUT1, CLKOUT2 (Pins E6, G6): Use these pins to

synchronize devices to either channel of the LTM8049.

ThesepinsoscillateatthesamefrequencyastheLTM8049

internal oscillator or, if active, the SYNC pin. The CLKOUT1

signal is about 180° out of phase with the oscillator of

channel1anddutycycleisabout50%.TheCLKOUT2signal

is in phase with the internal oscillator of channel 2 and its

duty cycle varies linearly with the internal temperature of

the LTM8049. Please refer to the Applications Information

section for detailed information on using CLKOUT2 as an

indication of the LTM8049 internal temperature. Do not

apply a voltage to this pin or use this pin to drive capaci-

tive loads greater than 120pF.

SHARE1, 2 (pins F3, F4): Connect these pins together if

the two outputs of the LTM8049 are paralleled. Otherwise,

leave these pins floating.

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