MAX16838_14 Datasheet, PDF (9/21 Pages) Maxim Integrated Products – Integrated, 2-Channel, High-Brightness LED Driver

MAX16838
Integrated, 2-Channel, High-Brightness LED Driver
with High-Voltage Boost and SEPIC Controller
PIN
TQFN
TSSOP
1
4
2
5
3
6
4
7
5
8
6
9
7
10
8
11
9
12
10
13
11
14
12
15
13
16
14
17
15
18
Pin Description
NAME
FUNCTION
NDRV
DRV
VCC
IN
EN
SGND
CFB
OV
ISET
FLT
OUT2
LEDGND
OUT1
RT
COMP
Gate Drive for Switching MOSFET. Connect NDRV to GATE directly or through a resistor
to control the rise and fall times of the gate drive.
5V Regulator Output. MOSFET gate-driver supply input. Bypass DRV to PGND with a
minimum of 1FF ceramic capacitor. Place the capacitor as close as possible to DRV
and PGND.
Internal Circuitry Supply Voltage. Bypass VCC to SGND with a minimum of 0.1FF
ceramic capacitor. Place the capacitor as close as possible to V_CC and SGND.
Supply Input. Connect a 4.75V to 40V supply to IN. Bypass IN to PGND with a minimum
of 1FF ceramic capacitor. For a 5V Q10% supply voltage, connect V_IN to V_CC.
Enable/Undervoltage Lockout (UVLO) Threshold Input. EN is a dual-function input.
Connect EN to V_IN through a resistor-divider to program the UVLO threshold.
Signal Ground. SGND is the current return path connection for the low-noise analog
signals. Connect SGND, LEDGND, and PGND at a single point.
Current Foldback Reference Input. Connect a resistor-divider between IN, CFB, and
ground to set the current foldback threshold. When the voltage at CFB goes below
1.23V, the LED current starts reducing linearly. Connect to V_CC to disable the current
foldback feature.
Overvoltage Threshold Adjust Input. Connect a resistor-divider from the switching
converter output to OV and SGND. The OV comparator reference is internally set to 1.23V.
LED Current Adjust Input. Connect a resistor R_ISET from ISET to SGND to set the
current through each LED string (I_LED) according to the formula I_LED = 1512V/R_ISET.
Open-Drain, Active-Low Flag Output. FLT asserts when there is an open/short-LED
condition at the output or when there is a thermal shutdown event.
LED String Cathode Connection 2. OUT2 is the open-drain output of the linear current
sink that controls the current through the LED string connected to OUT2. OUT2 sinks
up to 150mA.
LED Ground. LEDGND is the return path connection for the linear current sinks.
Connect SGND, LEDGND, and PGND at a single point.
LED String Cathode Connection 1. OUT1 is the open-drain output of the linear current
sink that controls the current through the LED string connected to OUT1. OUT1 sinks
up to 150mA.
Oscillator Timing Resistor Connection. Connect a timing resistor (RRT) from RT to SGND
to program the switching frequency. Apply an AC-coupled external clock at RT to
synchronize the switching frequency with an external clock source.
Switching Converter Compensation Input. Connect an RC network from COMP to SGND
(see the Feedback Compensation section).
Maxim Integrated
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