LTC4098(RevB) View Datasheet(PDF) - Linear Technology

Part Name

Description

MFG CO.

LTC4098
(Rev.:RevB)

USB Compatible Switching Power Managers/Li-Ion Chargers with Overvoltage Protection

Linear Technology 

LTC4098/LTC4098-1

PIN FUNCTIONS

VOUT (Pin 12): Output Voltage of the Switching PowerPath

Controller and Input Voltage of the Battery Charger. The

majority of the portable product should be powered from

VOUT. The LTC4098/LTC4098-1 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 power from VBUS or if the

VBUS power source is removed. VOUT should be bypassed

with a low impedance multilayer ceramic capacitor.

VBUS (Pin 13): Input Voltage for the Switching PowerPath

Controller. 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 impedance multilayer ceramic

capacitor.

SW (Pin 14): The SW pin delivers power from VBUS to

VOUT via the step-down switching regulator. An inductor

should be connected from SW to VOUT. See the Applica-

tions Information section for a discussion of inductance

value and current rating.

D0 (Pin 15): Mode Select Input Pin. D0, in combination with

the D1 pin and the D2 pin, controls the current limit and

battery charger functions of the LTC4098/LTC4098-1 (see

Table 1). This pin is pulled low by a weak current sink.

D1 (Pin 16): Mode Select Input Pin. D1, in combination with

the D0 pin and the D2 pin, controls the current limit and

battery charger functions of the LTC4098/LTC4098-1 (see

Table 1). This pin is pulled low by a weak current sink.

D2 (Pin 17): Mode Select Input Pin. D2, in combination

with the D0 pin and D1 pin, controls the current limit and

battery charger functions of the LTC4098/LTC4098-1 (see

Table 1). This pin is pulled low by a weak current sink.

WALL (Pin 18): External Power Source Sense Input.

WALL should be connected to the output of the external

high voltage switching regulator and to the drain of an

external P-channel MOS transistor. It is used to determine

when power is applied to the external regulator. When

power is detected, ACPR is driven low and the USB input

is automatically disabled.

ACPR (Pin 19): External Power Source Present Output

(Active Low). ACPR indicates that the output of the external

high voltage step-down switching regulator is suitable for

use by the LTC4098/LTC4098-1. It should be connected to

the gate of an external P-channel MOS transistor whose

source is connected to VOUT and whose drain is connected

to WALL. ACPR has a high level of VOUT and a low level

of GND.

VC (Pin 20): Bat-Track External Switching Regulator Control

Output. This pin drives the VC pin of a Linear Technology

external step-down switching regulator. In concert with

WALL and ACPR, it will regulate VOUT to maximize battery

charger efficiency.

Exposed Pad (Pin 21): Ground. The Exposed Pad must

be soldered to the PCB.

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