LTC3554EPD datasheet(12/36 Pages) LINER

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LTC3554

3554f

PIN FUNCTIONS

LTC3554 will partition the available power between the

external load on VOUT and the internal battery charger.

Priority is given to the external load and any extra power

is used to charge the battery. An ideal diode from BAT to

VOUT ensures that VOUT is powered even if the load exceeds

the allotted input current from VBUS or if the VBUS power

source is removed. VOUT should be bypassed with a low

impedance multilayer ceramic capacitor.

SUSP (Pin 19): Suspend Mode Logic Input. If this pin

is driven high the input current limit path is disabled.

In this state the circuit draws negligible power from the

VBUS pin. Any load at the VOUT pin is provided by the

battery through the internal ideal diode. When this input

is grounded, the input current limit will be set to desired

value as determined by the state of the HPWR pin. This

pin has a conditional internal pull-down resistor when

power is applied to the VBUS pin.

VBUS (Pin 20): USB Input Voltage. VBUS will usually be

connected to the USB port of a computer or a DC output

wall adapter. VBUS should be bypassed with a low imped-

ance multilayer ceramic capacitor.

Exposed Pad (Pin 21): Ground. The exposed package pad

is ground and must be soldered to the PC board for proper

functionality and for maximum heat transfer.

LTC3554EPD Datasheet(PDF) 12 Page - Linear Technology