ltc3576 Linear Technology Corporation, ltc3576 Datasheet - Page 14

• Manufacturer Part Number: ltc3576
• Description: Switching Power Manager With Usb On-the-go + Triple Step-down Dc/dcs
• Manufacturer: Linear Technology Corporation

LTC3576/LTC3576-1
DV
serial port is not needed, it can be disabled by grounding
DV
default values. See Table 3.
SCL (Pin 13): Clock Input Pin for the I
I
is grounded, the SCL pin is equivalent to the C2, C4 and
C6 bits in the I
determine the operating modes of switching regulators 1,
2 and 3 when DV
a 2μA internal pull-down current source.
SDA (Pin 14): Data Input Pin for the I
I
is grounded, the SDA pin is equivalent to the C3, C5 and
C7 bits in the I
determine the operating modes of switching regulators 1,
2 and 3 when DV
a 2μA internal pull-down current source.
NC (Pin 15): Unconnected Pin. This pin is not connected
internally to the part. It is permissible to tie this pin to V
in order to make the V
V
This pin will generally be connected to V
capacitor is recommended on this pin.
SW3 (Pin 17): Power Transmission Pin for Switching
Regulator 3.
NC (Pin 18): Unconnected Pin. This pin is not connected
internally to the part. It is permissible to tie this pin to SW3
in order to make the SW3 PCB trace wider.
EN3 (Pin 19): Logic Input. This logic input pin indepen-
dently enables switching regulator 3. Active high. This
pin is logically ORed with its corresponding bit in the
I
current source.
FB3 (Pin 20): Feedback Input for Switching Regulator 3.
When regulator 3’s control loop is complete, this pin servos
PIN FUNCTIONS
14
2
2
2
IN3
C logic levels are scaled with respect to DV
C logic levels are scaled with respect to DV
C serial port. See Table 3. Has a 2μA internal pull-down
CC
CC
. When DV
(Pin 16): Power Input for Switching Regulator 3.
(Pin 12): Logic Supply for the I
2
2
C serial port. SCL in conjunction with SDA
C serial port. SDA in conjunction with SCL
CC
CC
CC
is grounded, the I
is grounded. See Tables 3 and 5. Has
is grounded. See Tables 3 and 5. Has
IN3
PCB trace wider.
2
C bits are set to their
2
C Serial Port. If the
2
2
C Serial Port. The
C Serial Port. The
OUT
. A 1μF MLCC
CC
CC
. If DV
. If DV
IN3
CC
CC
to 1 of 16 possible set points based on the commanded
value from the I
RST3 (Pin 21): Logic Output. This in an open-drain output
which indicates that switching regulator 3 has settled to
its fi nal value. It can be used as a power-on reset for the
primary microprocessor or to enable the other switching
regulators for supply sequencing.
EN2 (Pin 22): Logic Input. This logic input pin indepen-
dently enables switching regulator 2. Active high. This
pin is logically ORed with its corresponding bit in the
I
current source.
SW2 (Pin 23): Power Transmission Pin for Switching
Regulator 2.
V
This pin will generally be connected to V
capacitor is recommended on this pin.
FB2 (Pin 25): Feedback Input for Switching Regulator 2.
When regulator 2’s control loop is complete, this pin servos
to 1 of 16 possible set points based on the commanded
value from the I
V
Output. This pin drives the V
Technology step-down switching regulator. An external P-
channel MOSFET is sometimes required to provide power
to V
Information). In concert with WALL and ACPR, it will
regulate V
WALL (Pin 27): 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 MOSFET if used. 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 au-
tomatically disabled. Pulling this pin above 4.3V enables
the V
2
C
IN2
C serial port. See Table 3. Has a 2μA internal pull-down
(Pin 26): Bat-Track External Switching Regulator Control
OUT
(Pin 24): Power Input for Switching Regulator 2.
C
pin.
with its gate tied to the ACPR pin (see Applications
OUT
to maximize battery charger effi ciency
2
2
C serial port. See Table 4.
C serial port. See Table 4.
C
pin of an external Linear
OUT
. A 1μF MLCC
3576f