34704_09 Datasheet, PDF (5/49 Pages) Freescale Semiconductor, Inc – Multiple Channel DC-DC Power Management IC

PIN CONNECTIONS
Table 2. 34704 Pin Definitions (continued)
A functional description of each pin can be found in the Functional Pin Description section beginning on page 17.
Pin Number Device Pin Name Pin Function
Formal Name
Definition
11
A/B PVIN3
Power
REG3 power supply input This is the connection to the drain of the high side switch FET.
voltage
Input decoupling /filtering is required for proper REG3 operation.
12
A/B
SW3
Output REG3 switching node
The inductor is connected between this pin and the regulated
REG3 output.
13
A/B VOUT3
Output
REG3 output voltage
This is the discharge path of REG3 output voltage.
return pin
14
A/B
FB3
Input
REG3 voltage feedback Connect the feedback resistor divider to this pin.
input for voltage
regulation/programming
15
A/B
SS
Input
Soft start time
The soft start time for all regulators can be adjusted by
connecting this pin to an external resistor divider between VDDI
and AGND pins.
16
A/B FREQ
Input
Oscillator frequency
The oscillator frequency can be adjusted by connecting this pin
to an external resistor divider between VDDI and AGND pins.
This pin sets F_SW1 value.
17
A/B
FB8
Input
REG8 voltage feedback Connect the feedback resistor divider to this pin.
input for voltage
regulation/programming
18
A/B
BT8
Passive REG8 bootstrap capacitor Connect a 0.01μF capacitor between this pin and SW8 pin to
input pin
enhance the gate of the Synchronous Power MOSFET.
19
A/B VOUT8
Output
REG8 regulated output Connect this pin directly to the load directly and to the output
voltage pin
filter as close to the pin as possible.
20
A/B
SW8
Output ^{REG8 switching node}
The inductor is connected between this pin and VIN pin.
21
A/B
SW1
Output ^{REG1 switching node}
The inductor is connected between this pin and VIN Pin.
22
A/B
VG
Passive REG1 regulated output REG1 regulated output voltage before the cut-off switch. This
voltage before the cutoff supplies the internal circuits and the gate drive
switch
23
A
VOUT1
Output
REG1 regulated output Connect this pin directly to the load directly and to the output
voltage pin.
filter as close to the pin as possible.
B
NC0 No Connect ^-
Pin 23 is not connected.
24
A/B
BT1
Passive REG1 bootstrap capacitor Connect a 1μF capacitor between this pin and SW1 pin to
input pin
enhance the gate of the Switch Power MOSFET.
25
A/B
SCL _Input/Output I²C serial interface clock I²C serial interface clock input.
input
26
A/B
SDA _Input/Output I²C serial interface data I²C serial interface data input.
input
27
A/B
RST Open Drain Power reset output signal This is an open drain output and must be pulled up by an
(Microprocessor Reset) external resistor to a supply voltage like V_IN.
28
A _{COMP7 Passive} REG7 compensation
REG7 compensation network connection.
network connection
B
NC1 No Connect ^-
Pin 28 is not connected
29
A
VREF7
Output
REG7 resistor feedback Connect this pin to the bottom of the feedback resistor divider.
network reference voltage
B
NC2 _{No Connect} -
Pin 29 is not connected
Analog Integrated Circuit Device Data
Freescale Semiconductor
34704
5