34701_07 Datasheet, PDF (4/38 Pages) Freescale Semiconductor, Inc – 1.5 A Switch-Mode Power Supply with Linear Regulator

PIN CONNECTIONS
Table 1. Pin Function Description (continued)
A functional description of each pin can be found in the FUNCTIONAL PIN DESCRIPTION section beginning on page 16.
Pin
Pin Name
Formal Name
Definition
20
CS
Current Sense
Current sense pin of the LDO. Overcurrent protection of the linear regulator external
power MOSFET. The voltage drop over the LDO current sense resistor RS is sensed
between the CS and LDO pins. The LDO current limit can be adjusted by selecting
the proper value of the current sensing resistor RS.
21
LDRV
Linear Drive
LDO gate drive of the external pass N-channel MOSFET.
22
VIN1
Input Voltage 1
The input supply pin for the integrated circuit. The internal circuits of the IC are
supplied through this pin.
23
VDDI
26
ADDR
Power Supply
Address
Internal supply voltage. A ceramic low ESR 1uF 6V X5R or X7R capacitor is
recommended.
I²C address selection. This pin can either be left open, tied to VDDI, or grounded
through a 10 kΩ resistor.
27
EN1
Enable 1
Enable 1 Input. The combination of the logic state of the Enable 1 and Enable 2
inputs determines operation mode and type of power sequencing of the IC.
28
EN2
Enable 2
Enable 2 Input. The combination of the logic state of the Enable 1 and Enable 2
inputs determines operation mode and type of power sequencing of the IC.
29
RT
Reset Timer
This pin allows programming of the Power-ON Reset delay by means of an external
RC network.
30
RST
Reset Output
(Active LOW)
The Reset Control circuit monitors both the switching regulator and the LDO
feedback voltages. It is an open drain output and has to be pulled up to some supply
voltage (e.g., the output of the LDO) by an external resistor.
31
CLKSEL
Clock Selection
This pin sets the CLKSYN pin as either an oscillator output or a synchronization input
pin. The CLKSEL pin is also used for the I²C address selection.
32
CLKSYN
Clock Synchronization Oscillator output/synchronization input pin.
34701
4
Analog Integrated Circuit Device Data
Freescale Semiconductor