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LM3423MHX

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Texas Instruments LED Drivers, HTSSOP-20-EP. Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.

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LM3423MHX

Texas Instruments · LED Drivers · HTSSOP-20-EP

LM3423MHX from Texas Instruments, in a HTSSOP-20-EP. Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin Name Type Function
1 VIN power_in Input voltage, recommended 4.5 V to 75 V, to be bypassed with a 100-nF capacitor to AGND as close to the device as possible.
2 EN input Enable: connect to AGND for zero-current shutdown, or apply more than 2.4 V to enable the device.
3 COMP input Compensation pin: connect a capacitor to AGND to set the control loop compensation.
4 CSH input Current sense high: connect a resistor to AGND to set the signal current, or a controlled current source or potentiometer to AGND for analog dimming.
5 RCT input Resistor-capacitor timing: the external RC network sets the predictive off-time and therefore the switching frequency.
6 AGND power_in Analog ground, connected to PGND through the DAP copper pad to provide the ground return for CSH, COMP, RCT and TIMR.
7 OVP input Overvoltage protection: connect to a resistor divider from VO to program OVLO, with a precision 1.24 V turnoff threshold and 23 µA (typical) hysteresis current.
8 nDIM input Dimming input and undervoltage protection: accepts a PWM signal and/or a VIN UVLO divider, with a 1.24 V turn-on threshold and 23 µA hysteresis current source.
9 FLT output Fault flag: N-channel open-drain output that goes high when a fault condition is latched by the timer, to be pulled up from VIN through a resistor.
10 TIMR input Fault timer: connect a capacitor to AGND to set the time delay before a sensed fault condition is latched.
11 LRDY output LED ready flag: N-channel open-drain output that pulls down when the LED current is not in regulation, to be pulled up from VIN through a resistor.
12 DPOL input Dim polarity: connect to AGND when dimming with a series P-channel MOSFET, or leave open when dimming with a series N-channel MOSFET.
13 DDRV output Dim gate drive output: connect to the gate of the dimming MOSFET.
14 PGND power_in Power ground, connected to AGND through the DAP copper pad to provide the ground return for GATE and DDRV.
15 GATE output Main gate drive output: connect to the gate of the main switching MOSFET, which is driven by a 2 Ω, 1 A peak gate driver.
16 VCC power_out Internal regulator output: bypass with a 2.2 µF to 3.3 µF ceramic capacitor to PGND.
17 IS input Main switch current sense: connect to the drain of the main N-channel MOSFET for RDS(on) sensing, or to a sense resistor in its source.
18 RPD input Resistor pulldown: connect the low side of all external resistor dividers (VIN UVLO, OVP) to implement zero-current shutdown.
19 HSP input LED current sense positive: connect through a series resistor to the positive side of the LED current sense resistor.
20 HSN input LED current sense negative: connect through a series resistor to the negative side of the LED current sense resistor.
21 DAP power_in Thermal pad on the bottom of the IC, acting as a star ground that connects AGND and PGND.

Key specifications

Parameter Value
Manufacturer Texas Instruments
Package HTSSOP-20-EP
Category LED Drivers
Pins 21

CAD (KiCad official)

  • Symbol: LM3423MHX
  • Footprint: Package_SO:TSSOP-20-1EP_4.4x6.5mm_P0.65mm_EP2.15x3.35mm
  • 3D model: HTSSOP-20-EP, generated from the KiCad footprint (body from the F.Fab outline, terminals on the pads, 1.2 mm nominal TSSOP height). Neither the vendor nor KiCad ships a 3D model for this package, so the dimensions are nominal, not the manufacturer's CAD (STEP)
  • 3D model files: lm3423mhx-etched.step / lm3423mhx-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); lm3423mhx.step / lm3423mhx.glb are the bare package body.

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

  • Datasheet: Texas Instruments datasheet (79 pp, sha256 5b165c52968afc7c, retrieved 2026-10-08, tier: lcsc)
  • Datasheet language: Chinese. Pin names, descriptions, and specs on this page were extracted and translated to English by ds2sf; the linked PDF is the manufacturer original.
  • Extractor: parts-factory 2.0.0 / extract_pins 0.3, primary claude-haiku-5-5 (text), consensus claude-sonnet-5-5 (agreed), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish.
  • CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF