LM3421 Datasheet, PDF (1/72 Pages) National Semiconductor (TI) – N-Channel Controllers for Constant Current LED Drivers

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LM3421, LM3421-Q1, LM3423, LM3423-Q1
SNVS574F – JULY 2008 – REVISED JULY 2015
LM342x/-Q1 N-Channel Controllers for Constant-Current LED Drivers
1 Features
•1 LM3421Q1/LM3423Q1 are Automotive Grade
Products That are AEC-Q100 Grade 1 Qualified
• LM3421Q0/LM3423Q0 are Automotive Grade
Products That are AEC-Q100 Grade 0 Qualified
• V_IN Range From 4.5 V to 75 V
• High-Side Adjustable Current Sense
• 2-Ω, 1-A Peak MOSFET Gate Driver
• Input Undervoltage and Output Overvoltage
Protection
• PWM and Analog Dimming
• Cycle-by-Cycle Current Limit
• Programmable Switching Frequency
• Zero Current Shutdown and Thermal Shutdown
• LED Output Status Flag (LM3423/23Q1/23Q0
Only)
• Fault Status Flag and Timer (LM3423/23Q1/23Q0
Only)
2 Applications
• LED Drivers: Buck, Boost, Buck-Boost, and
SEPIC
• Indoor and Outdoor Area SSL
• Automotive
• General Illumination
• Constant-Current Regulators
3 Description
The LM3421 and LM3423 family of devices are
versatile high voltage N-channel MOSFET controllers
for LED drivers. They can be easily configured in
buck, boost, buck-boost and SEPIC topologies. This
flexibility, along with an input voltage rating of 75 V,
makes the LM3421 and LM3423 devices ideal for
illuminating LEDs in a large family of applications.
Adjustable high-side current sense voltage allows for
tight regulation of the LED current with the highest
efficiency possible. The LM3421 and LM3423 devices
use predictive off-time (PRO) control, which is a
combination of peak current-mode control and a
predictive off-timer. This method of control eases the
design of loop compensation while providing inherent
input voltage feed-forward compensation.
The LM3421 and LM3423 devices include a high-
voltage start-up regulator that operates over a wide
input range of 4.5 V to 75 V. The internal PWM
controller is designed for adjustable switching
frequencies of up to 2 MHz, thus enabling compact
solutions.
Device Information⁽¹⁾
PART NUMBER
PACKAGE
BODY SIZE (NOM)
LM3421
LM3421-Q1
HTSSOP (16)
5.00 mm × 4.40 mm
LM3423
LM3423-Q1
HTSSOP (20)
6.50 mm × 4.40 mm
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
Typical Boost Application Circuit
VIN
1
VIN
LM3421
16
HSN
2
EN
15
HSP
3
COMP
14
RPD
4
CSH
5
RCT
13
IS
12
VCC
ILED
6
AGND
11
GATE
7
OVP
PWM
8
nDIM
DAP
10
PGND
9
DDRV
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.