Dual, 4A/2A, 4MHz, Step-Down DC-DC

Regulator with Tracking/Sequencing Capability

Pin Description

PIN

NAME

FUNCTION

1

SEL

Track/Sequence Select Input. Connect SEL to ground to configure the device as a sequencer. Connect

SEL to AVIN for tracking with output 1 as the master. Leave SEL unconnected for tracking with output 2

as the master. Use the output with the higher voltage as the master and the output with the lower voltage

as the slave.

2, 7, 8

PGND1

Power Ground Connection for Regulator 1. Connect the negative terminals of the input and output filter

capacitor to PGND1. Connect PGND1 externally to SGND at a single point, typically at the negative

terminal of the input capacitor.

3, 6

LX1

Inductor Connection for Regulator 1. LX1 is the drain connection of the internal high-side p-channel

MOSFET and the drain connection of the internal synchronous n-channel MOSFET for regulator 1.

4, 5

PVIN1

Input Supply Voltage for Regulator 1. Connect to an external voltage source from 2.5V to 5.5V. Bypass

PVIN1 to PGND1 with a 1µF (min) ceramic capacitor.

9

DVDD1

Switch Driver Supply for Regulator 1. Connect externally to PVIN1.

10

EN1

Enable Input for Regulator 1. When configured as a sequencer, EN1 must exceed 1.225V (typ) for the

PWM controller to begin regulating output 1. When configured as a tracker, connect EN1 to the center

tap of a resistive divider from the regulator 2 output.

11

FB1

Feedback Regulation Point for Regulator 1. Connect FB1 to the center tap of a resistive divider from the

regulator 1 output to SGND to set the output voltage. The FB1 voltage regulates to 0.6V (typ).

12

COMP1

Error-Amplifier Output for Regulator 1. Connect COMP1 to the compensation feedback network.

13, 14, 15,

20, 21, 22

N.C.

No Connection. Do not connect.

16

DVDD2

Switch Driver Supply for Regulator 2. Connect externally to PVIN2.

17

PGND2

Power Ground Connection for Regulator 2. Connect the negative terminals of the input and output filter

capacitors to PGND2. Connect PGND2 externally to SGND at a single point, typically at the negative

terminal of the input capacitor.

18

LX2

Inductor Connection for Regulator 2. LX2 is the drain connection of the internal high-side p-channel

MOSFET and the drain connection of the internal synchronous n-channel MOSFET for regulator 2.

19

PVIN2

Input Supply Voltage for Regulator 2. Connect to an external voltage source from 2.5V to 5.5V. Bypass

PVIN2 to PGND2 with a 1µF (min) ceramic capacitor.

23

COMP2

Error-Amplifier Output for Regulator 2. Connect COMP2 to the compensation feedback network.

24

FB2

Feedback Regulation Point for Regulator 2. Connect to the center tap of a resistive divider from the

regulator 2 output to SGND to set the output voltage. The FB2 voltage regulates to 0.6V (typ).

25

EN2

Enable Input for Regulator 2. When configured as a sequencer, EN2 must exceed 1.225V (typ) for the

PWM controller to begin regulating output 2. When configured as a tracker, connect EN2 to the center

tap of a resistive divider from the regulator 1 output.

26

SGND

Signal Ground. Connect SGND to PGND_ at a single point, typically near negative terminal of the input

bypass capacitor.

27

AVIN

Input Voltage. Bypass AVIN to SGND with a 100nF (min) ceramic capacitor.

28

RT

Oscillator Timing Resistor Connection. Connect a 4.2k

Ω to 33kΩ resistor from RT to SGND to program

the switching frequency from 500kHz to 4MHz.

—EP

Exposed Pad. Connect EP to a large copper plane at SGND potential to improve thermal dissipation. Do

not use as the main SGND connection.

MAX15021

Maxim Integrated

7