MAX16832CASA+T Maxim Integrated Products, MAX16832CASA+T Datasheet - Page 8

• Manufacturer Part Number: MAX16832CASA+T
• Description: IC LED DRIVER HIGH BRIGHT 8-SOIC
• Manufacturer: Maxim Integrated Products
• Type: HBLED Driverr

Specifications of MAX16832CASA+T

• Constant Current: Yes
• Topology: PWM, Step-Down (Buck)
• Number Of Outputs: 1
• Internal Driver: Yes
• Type - Primary: Automotive
• Type - Secondary: High Brightness LED (HBLED)
• Frequency: 2MHz
• Voltage - Supply: 6.5 V ~ 65 V
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width) Exposed Pad, 8-eSOIC. 8-HSOIC
• Operating Temperature: -40°C ~ 125°C
• Current - Output / Channel: 700mA
• Internal Switch(s): Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Output: -
• Efficiency: -
• Lead Free Status / Rohs Status: Details

2MHz, High-Brightness LED Drivers with
Integrated MOSFET and High-Side Current Sense
For stability and best efficiency, a low forward-voltage
drop diode with fast reverse-recovery time and low
capacitance is recommended. A Schottky diode is a
good choice as long as its breakdown voltage is high
enough to withstand the maximum operating voltage.
Careful PCB layout is critical to achieve low switching
losses and stable operation. In normal operation, there
are two power loops. One is formed when the internal
MOSFET is on and the high current flows from ground
through the input cap, R
inductor, and the internal MOSFET back to ground. The
second loop is formed when the internal MOSFET is off
and the high current circulates from the input cap posi-
tive terminal through R
tor, and the freewheeling diode and back to the input
cap positive terminal. Note that the current through
R
with some triangular ripple (low noise). The high-noise,
large signal, fast transition switching currents only flow
through the freewheeling diode to the input cap positive
8
Figure 2. Current-Regulator Operation
SENSE
_______________________________________________________________________________________
V
I
DIM
LED
, the LED load, and the inductor is basically DC
CURRENT
AVG. LED
HYSTERETIC
t1
Freewheeling-Diode Selection
MODE
SENSE
PCB Layout Guidelines
SENSE
, the LED load, the induc-
, the LED load, the
f
SW
terminal, or through the MOSFET to ground and then to
the input cap positive terminal. Without a proper PCB
layout, these square-wave switching currents can cre-
ate problems in a hysteretic LED driver.
The current control depends solely on the voltage
across R
erratic switching of the internal MOSFET (the IC will
operate at a much higher frequency). To help prevent
this, place R
and keep the sense traces short. It is especially impor-
tant to keep the square-wave switching currents in the
freewheeling diode away from R
interference, place the freewheeling diode on the oppo-
site side of the IC as R
capacitor near the diode so it can return the high fre-
quency currents to ground. The layout in Figure 3
should be used as a guideline. The dashed line shows
the path of the high frequency components that cause
disruption in operation. For a good thermal design, the
exposed pad on the IC should solder to a large pad
with many vias to the backside ground plane.
SENSE
SENSE
t2
. Any noise pickup on this node induces
as close as possible to CS and IN
SENSE
∆I
and position the input
SENSE
t
. To minimize
t