Digital Power-Supply Controller/Monitor

with PMBus Interface

8

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Pin Description

PIN

NAME

FUNCTION

1, 3

DVDD

Digital Power-Supply Input (3.3V, typ). Connect AVDD to DVDD externally. Connect a 0.1µF capacitor from

DVDD to DGND.

2

DGND

Digital Ground. Connect AGND to DGND externally close to the device.

4

CLKIO

Clock Input/Output. User-configurable clock input/output signal. The system controller can provide a clock

input to synchronize the time bases of multiple MAX8688 devices. Alternatively, a MAX8688 can provide a

1MHz output clock to other MAX8688s for synchronization. See the MFR_MODE (D1h) section.

5

RST

Active-Low SMBus Interface and Device Reset Line. Active-low logic input. See the RST Operation section.

6

SDA

SMBus Data Line

7

SCL

SMBus Clock Line

8, 9

N.C.

No Connection. Not internally connected.

10

ENOUT

On/Off Signal Open-Drain Output. Typically used to turn on/off a POL power supply under the PMBus

command or A3/ONOFF control. See the ENOUT Operation and MFR_MODE (D1h) sections.

11

FLT

Fault Output, Active-Low Open-Drain Output. Typically connected to system controller/master interrupt

input.

12

A3/ONOFF

Dual-Functioned Three-State MAX8688 Slave Address Identifier (MSB) and POL On/Off Control using the

MFR_MODE Command. See the MAX8688 Address Assignment and A3/ONOFF Operation sections.

13

A2/SDAE

MAX8688 Address Assignment and External EEPROM Interface sections.

14

A1/SCLE

the MAX8688 Address Assignment and External EEPROM Interface sections.

15

DACOUT

Analog Voltage Output of Internal 12-Bit DAC. Connect DACOUT to REFIN or FB of the DC-DC module with

high impedance in shutdown.

16

AGND

Analog Ground. Connect AGND to DGND externally close to the device.

17

AVDD

Analog Power-Supply Input (3.3V, typ). Connect AVDD to DVDD externally. Connect 0.1µF capacitor from

AVDD to AGND.

18

REFO

Buffered Reference Output. Connect a 1µF capacitor from REFO to ground.

19

RS_C

20

RS-

Differential Remote-Sense Input Return of the DC-DC Output Voltage. Connect RS- to the return terminal at

the load.

21

RS+

Differential Remote-Sense Input of DC-DC Output Voltage. Connect RS+ to the load terminal where the

output must be regulated.

22

ISN-

Differential-Sense Input Return of DC-DC Output Current. Connect ISN- to the negative end of the current-

(Figure 7).

23

ISN+

Differential-Sense Input of DC-DC Output Current. Connect ISN+ to the positive end of the current-sense

(Figure 7).

24

ISN_C

—EP

Exposed Pad. Connect EP to the AGND plane for the POL for best temperature measurement performance.

Do not use EP as the main ground connection.