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Texas Instruments LM3423Q1MHX/NOPB
- Part No.:
- LM3423Q1MHX/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 20-PowerTSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM3423Q1MHX/NOPB.pdf
- Description:
- IC LED DRIVER CTRLR PWM 20HTSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,399
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Product details
Overview
LM3423Q1MHX/NOPB from Texas Instruments is a high-voltage N-channel MOSFET LED controller for constant-current drivers in buck, boost, buck-boost, and SEPIC topologies. It supports 4.5 V to 75 V input, features predictive off-time (PRO) control, 1.24 V adjustable high-side current sense threshold, and integrated fault status flag and timer. It is used in automotive LED headlamp and tail lamp drivers requiring precise current regulation under wide input voltage variation.
For engineers reviewing the LM3423Q1MHX/NOPB datasheet, LM3423Q1MHX/NOPB pinout, LM3423Q1MHX/NOPB application, or LM3423Q1MHX/NOPB equivalent, key selection criteria include high-side differential current sensing capability, AEC-Q100 Grade 1 qualification, thermal shutdown at 165°C, and compatibility with external N-channel main and dimming FETs in high-reliability lighting systems.
Technical Context
The LM3423Q1MHX/NOPB implements Predictive Off-Time (PRO) control - a hybrid of peak current-mode control and input-voltage-proportional off-timer - enabling stable loop compensation and inherent input feed-forward without sub-harmonic oscillation up to 100% duty cycle. It uses a high-side transconductance amplifier (gM = 20 mA/V) with 1.24 V reference to regulate LED current via external RSNS, HSP/HSN differential inputs, and CSH feedback node.
It integrates dual gate drivers: GATE (2 Ω source / 1.3 Ω sink @ 25°C) for main switching FET, and DDRV (13.5 Ω source / 3.5 Ω sink @ 25°C) for external dimming FET. Fault management includes OVP (1.24 V threshold), thermal shutdown (165°C), and programmable fault timer via TIMR capacitor.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 4.5 V to 75 V - supports 12 V, 24 V, and 48 V automotive and industrial bus rails without pre-regulation. |
| Current Sense Threshold | 1.24 V ±5% - sets precision LED current via external RSNS; enables <50 mV minimum VSNS for high efficiency. |
| Switching Frequency | Up to 2 MHz - set by RCT/CT network; enables compact magnetics and low output ripple in space-constrained designs. |
| GATE Driver Strength | 2 Ω sourcing / 1.3 Ω sinking - drives N-channel MOSFET gates up to 1 A peak, minimizing switching losses in high-current LED strings. |
| OVP Threshold | 1.24 V with 23 µA hysteresis current - protects LED string from overvoltage via resistor divider on OVP pin; latchable fault behavior. |
| Thermal Shutdown | 165°C with 25°C hysteresis - prevents permanent damage during overload or poor heatsinking; automatic recovery after cooldown. |
| AEC-Q100 Grade | Grade 1 (–40°C to +125°C) - qualified for automotive cabin and exterior lighting per ISO 16750-2 and JESD22-A108. |
Pinout & Package
LM3423Q1MHX/NOPB is housed in a thermally enhanced 20-pin HTSSOP (PWP) package (6.50 mm × 4.40 mm) with exposed thermal pad (DAP) for star-ground connection between AGND and PGND.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Main power input | Bypassed with 100 nF ceramic capacitor to AGND; powers internal start-up regulator and UVLO circuitry. |
| EN | Enable input | Active-high logic input; >2.4 V enables operation; pulldown resistance 0.245–2.85 MΩ enables zero-current shutdown when grounded. |
| COMP | Error amplifier output | Connects to AGND via RC network for loop compensation; regulates CSH to 1.24 V for precise current control. |
| CSH | Current sense feedback | Sinks 100 µA signal current; regulated to 1.24 V; used for analog dimming or closed-loop current error amplification. |
| HSN / HSP | High-side current sense inputs | Differential pair across external RSNS; enables floating LED string sensing with common-mode range up to 76 V. |
| GATE | Main FET gate driver output | Drives N-channel switch gate with 2 Ω source / 1.3 Ω sink; supports fast turn-on/turn-off for high-frequency operation. |
| DDRV | Dimming FET gate driver | Drives external series dimming MOSFET; complements PWM/analog dimming with dedicated drive strength and timing. |
| OVP | Overvoltage protection input | Resistor divider from LED output sets 1.24 V trip point; fault latches until reset or power cycle. |
| nDIM | PWM dimming / UVLO input | Accepts PWM signal for digital dimming; also programs VIN UVLO threshold (1.24 V turn-on) via resistor divider. |
| AGND / PGND | Analog & power ground | Separated internally; connected externally via DAP copper pad to minimize noise coupling between sensing and switching paths. |
| RCT | Off-time timing input | RC network sets predictive off-time and thus switching frequency; VIN/25 reference (565 mV @ VIN=14 V) enables input feed-forward. |
| FLT / TIMR | Fault flag & timer | Open-drain FLT pulls low on fault; TIMR capacitor sets delay before fault latching (e.g., 10 ms for short-circuit detection). |
| IS | Main switch current sense | Connects to MOSFET drain or source for RDS(on)-based current limiting or external sense resistor placement. |
| RPD | Resistor pulldown | Common return for all external resistor dividers (nDIM, OVP); enables zero-current shutdown when pulled to AGND. |
| VCC | Internal LDO output | 7.35 V regulated output; bypassed with 2.2–3.3 µF ceramic capacitor to PGND; powers internal circuitry and gate drivers. |
| Thermal PAD (DAP) | Thermal & ground interface | Exposed copper pad on bottom; must be soldered to PCB thermal plane and star-grounded to AGND/PGND for RθJA = 36.7°C/W. |
Key Features
| Feature | Design Value |
|---|---|
| Predictive Off-Time (PRO) Control | Eliminates sub-harmonic oscillation at any duty cycle; enables stable operation in boost/buck-boost topologies up to 95% duty without slope compensation. |
| High-Side Differential Current Sensing | HSP/HSN inputs support floating LED strings up to 76 V common-mode voltage; rejects ground noise and enables accurate current regulation in high-side configurations. |
| Dual Independent Gate Drivers | GATE (1-A peak) controls main switching FET; DDRV (1-A peak) independently drives external dimming FET - enabling simultaneous PWM + analog dimming schemes. |
| Integrated Fault Management | Dedicated FLT open-drain flag and TIMR-programmable timer provide latched overvoltage, thermal, and current-fault reporting for ASIL-B–compliant diagnostics. |
| AEC-Q100 Qualified | Grade 1 qualification (–40°C to +125°C) with full temperature-range electrical testing ensures reliability in automotive exterior lighting applications. |
Applications
| Automotive Headlamp Driver | Industrial High-Bay Lighting |
|---|---|
Use Scenario: Constant-current driver for multi-string white LED arrays in adaptive front-lighting systems (AFS), operating from 9–16 V battery with load-dump transients. IC Role / Device Role / Timing Role: N-channel controller implementing boost topology with PRO control; regulates 700 mA per string with <±2% accuracy across temperature and input variation. Use Value: High-side sensing eliminates need for shunt on low-side return path, simplifying EMI filtering and enabling true high-side LED string configuration required for functional safety isolation. | Use Scenario: 48 V input LED driver for warehouse high-bay fixtures with 3–5 A total output current and 0–10 V analog dimming interface. IC Role / Device Role / Timing Role: Buck-boost controller with programmable 300 kHz switching frequency; manages wide VIN–VOUT differentials (48 V → 36–60 V) while maintaining tight current regulation. Use Value: RCT-based predictive off-time delivers consistent ripple and efficiency across line and load variations, reducing thermal stress on magnetics and improving system lifetime. |
| Commercial Streetlight Controller | Truck & Bus Tail Lamp Module |
Use Scenario: Outdoor-rated LED streetlight using SEPIC topology to maintain regulation during brownouts (VIN down to 4.5 V) and surges (up to 75 V). IC Role / Device Role / Timing Role: Controller with integrated OVP (programmed to 65 V) and thermal shutdown; coordinates with microcontroller via FLT flag for predictive maintenance alerts. Use Value: Fault status flag and timer enable autonomous fault logging without host MCU intervention - critical for remote, unattended installations. | Use Scenario: CAN-controlled rear lighting module with PWM dimming for brake/tail functions and analog dimming for position lamps, operating from 12 V vehicle bus. IC Role / Device Role / Timing Role: Dual-dimming-capable controller using nDIM for PWM and CSH for analog; supports fast 100 Hz–2 kHz dimming with <1 µs latency. Use Value: Independent DDRV gate driver allows separate dimming FET control, enabling independent brightness scaling for brake vs. tail LEDs without additional ICs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar N-channel LED controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3423MHX/NOPB | Commercial-grade (–40°C to +125°C); lacks AEC-Q100 qualification and FLT/TIMR pins; identical pinout and electrical specs otherwise. | No fault flag or timer; unsuitable for automotive safety-critical systems requiring diagnostic coverage. | Select LM3423MHX/NOPB only for cost-sensitive non-automotive applications where fault reporting is handled externally. |
| LM3423Q0MHX/NOPB | AEC-Q100 Grade 0 (–40°C to +150°C); adds LED output status flag (LRDY) and enhanced thermal margin; same 20-pin HTSSOP package. | Supports under-hood applications (e.g., daytime running lights) requiring extended junction temperature rating. | Choose LM3423Q0MHX/NOPB when ambient temperatures exceed 125°C or LRDY flag is needed for LED-on confirmation. |
Compared with LM3423MHX/NOPB, LM3423Q1MHX/NOPB adds automotive qualification and integrated fault diagnostics; compared with LM3423Q0MHX/NOPB, it trades extended temperature range for lower cost and standard Grade 1 compliance - making it optimal for cabin and exterior lighting below 125°C ambient.
Availability
LM3423Q1MHX/NOPB is available at Aetrix Electronics and suitable for automotive lighting, industrial high-bay fixtures, and outdoor streetlighting requiring stable component supply, AEC-Q100 traceability, and long-term production continuity.
Supply support for LM3423Q1MHX/NOPB includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Texas Instruments is a global semiconductor company specializing in analog, embedded processing, and power management ICs, with leadership in automotive, industrial, and lighting control solutions.
The LM342x family was designed specifically for high-reliability constant-current LED drivers in automotive and industrial environments, emphasizing wide-input operation, high-side sensing, and robust fault protection.
FAQ
What is the maximum input voltage supported by the LM3423Q1MHX/NOPB?
The LM3423Q1MHX/NOPB supports an absolute maximum input voltage of 76 V and operates continuously from 4.5 V to 75 V. This wide range enables direct connection to 12 V, 24 V, and 48 V automotive and industrial power buses, including transient conditions like load dump (per ISO 7637-2). The internal start-up regulator remains functional across this full range, ensuring reliable startup even at minimum VIN.
Does the LM3423Q1MHX/NOPB support both PWM and analog dimming simultaneously?
Yes, the LM3423Q1MHX/NOPB supports concurrent PWM and analog dimming: nDIM accepts a PWM signal for digital brightness control, while the CSH pin can be biased with a DC voltage or current source to adjust the 1.24 V reference point for analog current scaling. This dual-path capability allows fine-grained dimming resolution in automotive lighting systems where both fast-response braking and smooth ambient adjustment are required.
How is overvoltage protection configured on the LM3423Q1MHX/NOPB?
Overvoltage protection on the LM3423Q1MHX/NOPB is configured by connecting a resistor divider from the LED output (VO) to the OVP pin and AGND. The internal comparator trips when the OVP pin voltage reaches 1.24 V, corresponding to VO = 1.24 V × (R1 + R2)/R2. A 23 µA hysteresis current source provides turn-on hysteresis, and the FLT pin asserts an open-drain fault flag that latches until power cycle or reset - enabling fail-safe LED string protection.
What package type and thermal characteristics does the LM3423Q1MHX/NOPB have?
The LM3423Q1MHX/NOPB uses a 20-pin HTSSOP (PWP) package measuring 6.50 mm × 4.40 mm with an exposed thermal pad (DAP). Its junction-to-ambient thermal resistance (RθJA) is 36.7°C/W with proper PCB copper area, and junction-to-case (bottom) resistance is 1.9°C/W. The DAP must be star-grounded to both AGND and PGND to achieve rated thermal performance and ensure stable operation at full load.
Is the LM3423Q1MHX/NOPB pin-compatible with other devices in the LM342x family?
The LM3423Q1MHX/NOPB shares the same 20-pin HTSSOP footprint and pinout with LM3423, LM3423Q0MHX/NOPB, and LM3423MHX/NOPB. However, it is not pin-compatible with the 16-pin LM3421 variants. Key distinguishing pins - FLT, TIMR, LRDY, and DPOL - are present only on 20-pin versions; unused pins on LM3423Q1MHX/NOPB must remain unconnected or tied per datasheet guidance.
LM3423Q1MHX/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 20-PowerTSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- DC DC Controller
- Topology:
- SEPIC, Step-Down (Buck), Step-Up (Boost)
- Internal Switch(s):
- No
- Number of Outputs:
- 1
- Voltage - Supply (Min):
- 4.5V
- Voltage - Supply (Max):
- 75V
- Voltage - Output:
- -
- Current - Output / Channel:
- -
- Frequency:
- 2MHz
- Dimming:
- Analog, PWM
- Applications:
- -
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-HTSSOP
LM3423Q1MHX/NOPB FAQ
1.How can I place an order for LM3423Q1MHX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3423Q1MHX/NOPB on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for LM3423Q1MHX/NOPB reliable?
The price and inventory of LM3423Q1MHX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3423Q1MHX/NOPB is usually 5 days.
3.What payment methods are accepted for LM3423Q1MHX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3423Q1MHX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3423Q1MHX/NOPB?
LM3423Q1MHX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3423Q1MHX/NOPB order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for LM3423Q1MHX/NOPB?
For technical support, including LM3423Q1MHX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3423Q1MHX/NOPB requirements.
6.How does Aetrix verify that LM3423Q1MHX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3423Q1MHX/NOPB products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LM3423Q1MHX/NOPB meets industry standards.
7.What is the process for return or replacement of LM3423Q1MHX/NOPB?
All LM3423Q1MHX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3423Q1MHX/NOPB, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The LM3423Q1MHX/NOPB part is unused and in its original packaging.
Return procedure for LM3423Q1MHX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM3423Q1MHX/NOPB Tags
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BCR402RE6327HTSA1
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BCR430UXTSA2
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BCR420UE6433HTMA1
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BCR420UE6327HTSA1
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BCR421UE6327HTSA1
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LYT1604D-TL
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HV9910CLG-G
Microchip Technology
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CL2N8-G
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BCR420UW6-7
Diodes Incorporated
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BCR421UW6-7
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BCR420UFD-7
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