MAX5986A MAXIM [Maxim Integrated Products], MAX5986A Datasheet - Page 10

• Manufacturer Part Number: MAX5986A
• Description: IEEE 802.3af-Compliant, High-Efficiency, Class 1,Powered Devices with Integrated DC-DC Converter
• Manufacturer: MAXIM [Maxim Integrated Products]

Powered Devices with Integrated DC-DC Converter
MAX5986A
6, 10, 11
IEEE 802.3af-Compliant, High-Efficiency, Class 1,
12
13
14
15
16
—
—
—
5
7
8
9
PIN
MAX5987A
6, 9, 10
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12
13
14
15
16
11
—
—
—
5
7
8
LDO_FB
RESET
NAME
PGND
VDRV
RREF
GND
WAD
ULP
V
V
FB
SL
EP
DD
CC
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.
Ground. Reference Rail for the Device. It is also the “quiet” ground for all voltage
reference (e.g. FB is referenced to this GND).
Internal 5V Regulator Voltage Output. The internal voltage regulator provides 5V to the
MOSFET driver and other internal circuits. V
drive external circuits. Connect a 1Ff bypass capacitor between V
Sleep Mode Enable Input. A falling edge on SL brings the device into sleep mode. An
external resistor (R
Ultra-Low Power-Mode Enable Input. ULP has an internal 50kI pullup resistor to the
internal 5V bias rail. A falling edge on SL while ULP is asserted low enables ultra-low
power mode. When ultra-low power mode is enabled, the power consumption of the
device is reduced even lower than sleep mode to comply with ultra-low power sleep
power requirements while still supporting MPS.
Wall Power Adapter Detector Input. Wall adapter detection is enabled when the voltage
from WAD to GND is greater than 8.8V. When a wall power adapter is present, the
isolation p-channel power MOSFET turns off. Connect WAD directly to GND when the
wall power adapter or other auxiliary power source is not used.
Positive Supply Input. Connect a 68nF (min) bypass capacitor between V
DC-DC Converter Power Input. V
MOSFET. Connect a 10FF capacitor in parallel with a 1FF ceramic capacitor between
V
Power Ground. Power ground of the DC-DC converter power stage. Connect PGND
to GND with a star connection. Do not use PGND as reference for sensitive feedback
circuit.
Signature Resistor Connection. Connect a 24.9kI resistor (R
LDO Regulator Feedback Input. Connect to V
of 3.3V, or connect to a resistive divider from the LDO_OUT to GND for an adjustable
LDO output voltage.
Open-Drain RESET Output. The RESET output is driven low if either LDO_OUT or FB
drops below 90% of its set value. RESET goes high 100Fs after both LDO_OUT and FB
rise above 95% of their set values. Leave unconnected when not used.
Exposed Pad. Connect the exposed pad to ground.
CC
and PGND.
SL
) connected between SL and GND sets the LED current (I
MAX5986A/MAX5987A
DD
is connected to V
FUNCTION
Pin Description (continued)
DRV
DRV
is referenced to GND. Do not use V
to get the preset LDO output voltage
CC
by an isolation p-channel
SIG
DRV
) to GND.
and GND.
DD
and PGND.
LED
DRV
).
to