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LM3423Q1MHX

Public Made by Adom

by adom

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

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LM3423Q1MHX

Texas Instruments · LED Drivers · HTSSOP-20-EP

LM3423Q1MHX 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, specified from 4.5 V to 75 V; bypass 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; connect a capacitor to AGND to set the 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 thus the switching frequency.
6 AGND power_in Analog ground; connect 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 1.24-V turnoff threshold and 23-µA hysteresis current.
8 nDIM input Dimming input and undervoltage protection; connect a PWM signal and/or a VIN resistor divider to program UVLO, with a 1.24-V turnon threshold and 23-µA hysteresis current.
9 FLT output Fault flag; an N-channel open-drain output that goes high when a fault condition is latched by the timer, used with a pullup resistor from VIN.
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; an N-channel open-drain output that pulls down when the LED current is not in regulation, used with a pullup resistor from VIN.
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; connect 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.
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 Nixie Tube Driver/LED Driver
Pins 21

CAD (KiCad official)

  • Symbol: LM3423Q1MHX
  • 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: lm3423q1mhx-etched.step / lm3423q1mhx-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); lm3423q1mhx.step / lm3423q1mhx.glb are the bare package body.

Provenance

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

  • Datasheet: Texas Instruments datasheet (80 pp, sha256 e82ddb4d986b65c0, retrieved 2026-10-11, tier: lcsc)
  • 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