6 Pin Configuration and Functions

(There is no electric signal down bonded to thermal pad inside IC. Exposed thermal pad must be soldered to PCB for optimal thermal performance.)

Figure 6-1 RHB Package32 Pins(Top View)

Table 6-1 Pin Functions

PIN		DESCRIPTION
NAME	NO.	DESCRIPTION
LVIN2	1	Input power supply for LDO2. Connect LVIN2 pin as close as possible to the (+) terminal of an input ceramic capacitor (suggest 1 µF).
LOUT2	2	LDO2 output. Connect LOUT2 pin as close as possible to the (+) terminal of an output ceramic capacitor (suggest 1 µF).
LFB2	3	Feedback Kelvin sensing pin for LDO2 output voltage. Connect this pin to LDO2 resistor divider.
LEN2	4	Enable for LDO2. Float to enable.
PGOOD	5	An open-drain output, asserts low if the output voltage of any buck is beyond regulation range due to thermal shutdown, overcurrent, undervoltage, or ENx shut down.
MODE	6	When high, an automatic power-up or power-down sequence is provided according to the states of EN1, EN2, and EN3 pins.
FB2	7	Feedback Kelvin sensing pin for buck2 output voltage. Connect this pin to buck2 resistor divider.
EN2	8	Enable for buck2. Float to enable. Can use this pin to adjust the input undervoltage lockout of buck2 with a resistor divider.
BST2	9	Boot-strapped supply to the high-side floating gate driver in buck2. Connect a capacitor (recommend 47 nF) from BST2 pin to LX2 pin.
LX2	10	Switching node connection to the inductor and bootstrap capacitor for buck2. The voltage swing at this pin is from a diode voltage below the ground up to VIN2 voltage.
PGND2	11	Power ground connection of buck2. Connect PGND2 pin as close as possible to the (–) terminal of VIN2 input ceramic capacitor.
VIN2	12	Input power supply for buck2. Connect VIN2 pin as close as possible to the (+) terminal of an input ceramic capacitor (suggest 10 µF).
VIN3	13	Input power supply for buck3. Connect VIN3 pin as close as possible to the (+) terminal of an input ceramic capacitor (suggest 10 µF).
PGND3	14	Power ground connection of buck3. Connect PGND3 pin as close as possible to the (–) terminal of VIN3 input ceramic capacitor.
LX3	15	Switching node connection to the inductor and bootstrap capacitor for buck3. The voltage swing at this pin is from a diode voltage below the ground up to VIN3 voltage.
BST3	16	Boot-strapped supply to the high-side floating gate driver in buck3. Connect a capacitor (recommend 47 nF) from BST3 pin to LX3 pin.
EN3	17	Enable for buck3. Float to enable. Can use this pin to adjust the input undervoltage lockout of buck3 with a resistor divider.
FB3	18	Feedback Kelvin sensing pin for buck3 output voltage. Connect this pin to buck3 resistor divider.
AGND	19	Analog ground common to buck controllers and other analog circuits. It must be routed separately from high-current power grounds to the (–) terminal of the bypass capacitor of input voltage VIN.
V7V	20	Internal LDO for gate driver and internal controller. Connect a 10-µF capacitor from the pin to power ground.
COMP1	21	Error amplifier output and loop compensation pin for buck1. Connect a series resistor and capacitor to compensate the control loop of buck1 with peak current PWM mode.
SS1	22	Soft-start and tracking input for buck1. An internal 5-µA pullup current source is connected to this pin. The soft-start time can be programmed by connecting a capacitor between this pin and ground.
FB1	23	Feedback Kelvin sensing pin for buck1 output voltage. Connect this pin to buck1 resistor divider.
EN1	24	Enable for buck1. Float to enable. Can use this pin to adjust the input undervoltage lockout of buck1 with a resistor divider.
BST1	25	Boot-strapped supply to the high side floating gate driver in buck1. Connect a capacitor (recommend 47 nF) from BST1 pin to LX1 pin.
LX1	26	Switching node connection to the inductor and bootstrap capacitor for buck1. The voltage swing at this pin is from a diode voltage below the ground up to VIN1 voltage.
PGND1	27	Power ground connection of Buck1. Connect PGND1 pin as close as possible to the (–) terminal of VIN1 input ceramic capacitor.
VIN1	28	Input power supply for buck1. Connect VIN1 pin as close as possible to the (+) terminal of an input ceramic capacitor (suggest 10 µF).
LEN1	29	Enable for LDO1. Float to enable.
LFB1	30	Feedback Kelvin sensing pin for LDO1 output voltage. Connect this pin to LDO1 resistor divider.
LOUT1	31	LDO1 output. Connect LOUT1 pin as close as possible to the (+) terminal of an output ceramic capacitor (suggest 1 µF).
LVIN1	32	Input power supply for LDO1. Connect LVIN1 pin as close as possible to the (+) terminal of an input ceramic capacitor (suggest 1 µF).
PAD	—	There is no electric signal down bonded to thermal pad inside IC. Exposed thermal pad must be soldered to PCB for optimal thermal performance.