MAX16822A_10 Datasheet, PDF (5/10 Pages) Maxim Integrated Products – 2MHz, High-Brightness LED Drivers with Integrated MOSFET and High-Side Current Sense

2MHz, High-Brightness LED Drivers with
Integrated MOSFET and High-Side Current Sense
Typical Operating Characteristics (continued)
(V_IN = V_DIM = 48V, C_VCC = 1µF, R_SENSE = 0.62Ω, L = 220µH (connected between IN and CS). Typical values are at T_A = +25°C,
unless otherwise noted.)
LXRDSON
vs. TEMPERATURE
1.0
VIN = 65V
0.9
0.8
VIN = 48V
0.7
VIN = 6.5V
0.6
0.5
0.4
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
ITEMP_I
vs. TEMPERATURE
30.0
29.5
29.0
28.5
28.0
27.5
27.0
26.5
26.0
25.5
VIN = 48V
25.0
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
Pin Description
PIN
NAME
FUNCTION
1
CS
Current-Sense Input. Connect a resistor between IN and CS to program the LED current.
2
IN
Positive Supply Voltage Input. Bypass with a 1μF or higher value capacitor to GND.
3
GND
Ground
4
PGND
Power Ground
5, 6
LX
Switching Node
7
DIM
Logic-Level Dimming Input. Drive DIM low to turn off the current regulator. Drive DIM high to
enable the current regulator.
8
TEMP_I
Thermal Foldback Control and Linear Input. Bypass with a 0.01μF capacitor to GND if thermal
foldback or analog dimming is used. See the Thermal Foldback section for more details.
Detailed Description
The MAX16822A/MAX16822B are step-down, constant-
current, high-brightness LED (HB LED) drivers. These
devices operate from a +6.5V to +65V input-voltage
range. The maximum output current is 500mA, if the
part is used at temperatures up to +105°C, or 350mA, if
it is used up to +125°C. A high-side current-sense
resistor sets the output current and a dedicated PWM
dimming input enables pulsed LED dimming over a
wide range of brightness levels.
A high-side current-sensing scheme and an on-board
current-setting circuitry minimize the number of exter-
nal components while delivering LED current with ±3%
accuracy, using a 1% sense resistor. See Figure 1 for
an internal block diagram.
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