MAX5986A/MAX5986B/MAX5987A

IEEE 802.3af-Compliant, High-Efficiency, Class 1/

Class 2, PDs with Integrated DC-DC Converter

11

Maxim Integrated

Pin Description

Pin Configurations

PIN

NAME

FUNCTION

MAX5986A MAX5986B MAX5987A

1

1

1

AUX

Auxiliary Voltage Input. Auxiliary input to the internal regulator (VDRV).

Connect AUX to the output of the buck converter if the output voltage is

greater than 4.75V to back bias the internal circuitry and increase efficiency.

Connect to a clean ground when not used.

2

2

2

LX

Inductor Connection. Inductor connection for the internal DC-DC converter.

3

3

—

LED

250Hz with 25% duty cycle.

—

—

3

LDO_IN

LDO Input Voltage. Connect LDO_IN to output when used, otherwise connect to

GND. Connect a minimum 1FF bypass capacitor between LDO_IN and GND.

4

4

—

WK

Wake Mode Enable Input. WK has an internal 50kI pullup resistor to the

internal 5V bias rail. A falling edge on WK brings the device out of sleep mode

and into the normal operating mode (wake mode).

—

—

4

LDO_OUT

LDO Output Voltage. Connect a minimum 1FF output capacitor between

LDO_OUT and GND.

5

5

5

FB

Feedback. Feedback input for the DC-DC buck converter. Connect FB to a

resistive divider from the output to GND to adjust the output voltage.

15

16

14

13

6

5

7

8

12

4

12

11

9

PGND

RREF

*EP

*EP

*EXPOSED PAD, CONNECT TO GND

( ) Applies to MAX5986B

*EXPOSED PAD, CONNECT TO GND

SL

VDRV

GND

FB

+

3

10

TQFN

MAX5986A

MAX5986B

TOP VIEW

15

16

14

13

6

5

7

8

12

4

12

11

9

PGND

RREF

LDO_FB

VDRV

GND

FB

+

3

10

TQFN

MAX5987A