Datasheet

LED Driver with Integrated MOSFET
for MR16 and Other 12V AC Input Lamps
Pin Configuration
Pin Description
1
3
4
10
8
7
SOURCE
FB
GND
DRAIN
IN
EP
+
EXT
MAX16840
2 9
SOURCEDRAIN
5 6
REFICOMP
TDFN
TOP VIEW
PIN NAME FUNCTION
1, 2 DRAIN Drain of the Internal Switching MOSFET
3 IN
Input. Connect to LED string anode in boost and buck-boost configuration to get OVP protection
during open LED. Bypass it with a sufficient capacitor not to allow IN to go below 6.5V in buck
applications.
4 EXT Base Drive for External Bipolar Until Internal Driver Starts Switching for the First Time After Power-Up
5 COMP
Compensation Component Connection for the Switching Stage. Connect a suitable RC network to
ground. This is the output of the g
m
amplifier
6 REFI
Analog Dimming and Thermal Foldback. The IC sources 50µA current out of this pin. Whenever this
pin voltage is > 1.2V, the FB voltage is regulated to internal 200mV reference. Whenever this pin
voltage < 1.2V, the FB voltage is regulated to V
REFI
/6. Leave this pin unconnected to disable this
foldback feature.
7 GND Ground
8 FB
Current-Sense. This pin includes a 5kI/4pF RC filter at its input to average the current information
over the switching cycle. Connect this pin directly to SOURCE.
9, 10 SOURCE Source of the Internal Switching MOSFET
— EP
Exposed Pad. Connect EP to the ground plane for heatsinking. Do not use the EP as the only
electrical connection to ground.
Maxim Integrated
5
MAX16840
Maxim Integrated
5