LM3423MHBKBSTEV/NOPB National Semiconductor, LM3423MHBKBSTEV/NOPB Datasheet - Page 9

• Manufacturer Part Number: LM3423MHBKBSTEV/NOPB
• Description: BOARD EVAL BUCK BOOST LM3423
• Manufacturer: National Semiconductor
• Series: PowerWise®r

Specifications of LM3423MHBKBSTEV/NOPB

• Current - Output / Channel: 1A
• Outputs And Type: 1, Non-Isolated
• Voltage - Output: 35V
• Features: Dimmable
• Voltage - Input: 4.5 ~ 35V
• Utilized Ic / Part: LM3423
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: LM3423MHBKBSTEV

Block Diagram
Theory of Operation
The LM3421/23 are N-channel MosFET (NFET) controllers
for buck, boost and buck-boost current regulators which are
ideal for driving LED loads. The controller has wide input volt-
age range allowing for regulation of a variety of LED loads.
The high-side differential current sense, with low adjustable
threshold voltage, provides an excellent method for regulating
output current while maintaining high system efficiency. The
LM3421/23 uses a Predictive Off-time (PRO) control archi-
tecture that allows the regulator to be operated using minimal
external control loop compensation, while providing an inher-
9
ent cycle-by-cycle current limit. The adjustable current sense
threshold provides the capability to amplitude (analog) dim
the LED current and the output enable/disable function with
external dimming FET driver allows for fast PWM dimming of
the LED load. When designing, the maximum attainable LED
current is not internally limited because the LM3421/23 is a
controller. Instead it is a function of the system operating
point, component choices, and switching frequency allowing
the LM3421/23 to easily provide constant currents up to 5A.
This controller contains all the features necessary to imple-
ment a high efficiency versatile LED driver.
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