MP4689 – 100V INPUT, 1A HIGH POWER LED DRIVER
MP4689 Rev. 1.01 www.MonolithicPower.com 4
4/14/2015 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2015 MPS. All Rights Reserved.
PIN FUNCTIONS
SOIC8E
Pin #
Name Description
1 FB
Feedback. This is the input to hysteretic comparators. An external current sensing resistor is
connected in series with the LEDs to GND. The feedback voltage is connected to this pin
and is regulated at +200mV with 15% current ripple.
2 N/C Not connected
3 VIN
Input Supply. This supplies power to all the internal control circuitry, both BS regulators and
the high-side switch. A decoupling capacitor to ground must be placed close to this pin to
minimize switching spikes.
4 BST
Bootstrap. This is the positive power supply for the internal floating high-side MOSFET
driver. Connect a bypass capacitor between this pin and SW pin.
5 SW
Switch Node. This is the output from the high-side switch. A low V
F
Schottky rectifier to
ground is required. The rectifier must be close to the SW pins to reduce switching spikes.
6 DIM
PWM Dimming Input. Pulling this pin below the specified threshold for dimming off. Pulling it
up above the specified threshold for dimming on. If there is no need for dimming function,
connect DIM and EN pins together.
7 EN
Enable Input. Pulling this pin below the specified threshold shuts the chip down. Pulling it up
above the specified threshold or leaving it floating enables the chip.
8
GND,
Exposed
pad
Ground. It should be connected as close as possible to the output capacitor avoiding the
high current switch paths. Connect exposed pad to GND plane for optimal thermal
performance.
