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Texas Instruments LM3421Q0MH/NOPB
- Part No.:
- LM3421Q0MH/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 16-PowerTSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM3421Q0MH/NOPB.pdf
- Description:
- IC LED DRIVER CTRLR PWM 16HTSSOP
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
LM3421Q0MH/NOPB from Texas Instruments is an AEC-Q100 Grade 0 qualified high-voltage N-channel MOSFET controller for constant-current LED drivers, supporting buck, boost, buck-boost, and SEPIC topologies. It operates from 4.5 V to 75 V input, features predictive off-time (PRO) control, 2-Ω/1-A peak gate drive, and programmable switching frequency up to 2 MHz - enabling compact, high-efficiency LED lighting in automotive front lighting and industrial area illumination.
For engineers reviewing the LM3421Q0MH/NOPB datasheet, LM3421Q0MH/NOPB pinout, LM3421Q0MH/NOPB application, or LM3421Q0MH/NOPB equivalent, this page delivers verified technical context, validated pin functions, real-world dimming interface behavior, thermal shutdown thresholds, and substitution guidance grounded in TI's official SNVS574G revision G documentation.
Technical Context
The LM3421Q0MH/NOPB implements Predictive Off-Time (PRO) control - a hybrid of peak current-mode regulation and input-voltage-proportional off-timer - delivering inherent input feed-forward compensation and eliminating sub-harmonic oscillation at any duty cycle. Its high-side differential current sense (HSP/HSN) enables precise LED current regulation with adjustable 1.24 V reference and 20 mA/V transconductance amplifier.
It integrates a wide-input (4.5–75 V) start-up regulator generating 6.9 V ±0.45 V on VCC, supports both PWM dimming via nDIM and analog dimming via CSH, and includes cycle-by-cycle current limiting via IS pin with 245 mV threshold. Thermal shutdown activates at 165°C with 25°C hysteresis, and fault protection includes OVP (1.24 V threshold), UVLO (1.24 V on nDIM), and zero-current shutdown via RPD.
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/industrial rails without external pre-regulation. |
| Switching Frequency | Up to 2 MHz - enables use of small inductors & capacitors; set via RCT resistor and capacitor network. |
| Current Sense Threshold | 1.24 V (±5%) on CSH - sets LED current accuracy; used with external RHSP/RCSH/RSNS for <±3% ILED regulation. |
| 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. |
| Thermal Shutdown | 165°C activation with 25°C hysteresis - protects against sustained overload or poor PCB thermal design. |
| OVP Threshold | 1.24 V on OVP pin - triggers shutdown when output exceeds programmed level; hysteresis provided by 23 µA current source. |
| EN Threshold | 2.4 V turn-on / 0.8 V turn-off - provides clean enable/disable with 0.1 V hysteresis; internal 0.245–2.85 MΩ pulldown ensures default-off state. |
Pinout & Package
LM3421Q0MH/NOPB is housed in a 16-pin HTSSOP (PWP) package measuring 5.00 mm × 4.40 mm with exposed thermal pad (DAP) for enhanced heat dissipation. The DAP must be star-grounded to AGND and PGND per TI layout guidelines.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (1) | Main power input | Bypassed with 100 nF ceramic capacitor to AGND; powers internal regulator and high-voltage circuitry. |
| EN (2) | Enable control input | Logic-level input: ≥2.4 V enables operation; ≤0.8 V forces zero-current shutdown; internal pulldown ensures safe default-off. |
| COMP (3) | Error amplifier compensation node | Connects RC network to AGND to stabilize control loop; typical pole-zero placement sets bandwidth for PRO control. |
| CSH (4) | High-side current sense amplifier output | Sinks 100 µA nominal signal current; regulated to 1.24 V for precise LED current setting via external resistors. |
| RCT (5) | Predictive off-time timing input | RC network here sets switching frequency; voltage decays from VIN/25 (~565 mV) to trigger off-time timer. |
| nDIM (8) | PWM dimming & UVLO input | Accepts 100–500 Hz PWM signal; also programs UVLO threshold (1.24 V) using resistor divider from VIN. |
| VCC (12) | Internal LDO output | 6.9 V ±0.45 V regulated supply; bypassed with 2.2–3.3 µF ceramic cap to PGND for gate driver stability. |
| GATE (11) | Main MOSFET gate driver output | 2 Ω sourcing / 1.3 Ω sinking capability; drives N-channel switch directly; requires low-inductance layout. |
| PGND (10) | Power ground return | Return path for GATE and DDRV; connected to AGND via DAP copper pad to minimize ground bounce. |
| DDRV (9) | Dimming MOSFET gate driver | Drives external dimming FET; 13.5 Ω sourcing / 3.5 Ω sinking; enables fast PWM dimming independent of main switch. |
| HSN (16) | High-side current sense negative | Connects to low side of RSNS; forms differential pair with HSP to reject common-mode noise in LED string. |
| HSP (15) | High-side current sense positive | Connects to high side of RSNS; matched bias current cancellation (via RHSN = RHSP) improves accuracy. |
| IS (13) | Main switch current sense | Monitors MOSFET drain or source for cycle-by-cycle current limit; 245 mV threshold triggers immediate shutdown. |
| OVP (7) | Output overvoltage protection input | Resistor divider from VO sets 1.24 V trip point; 23 µA hysteresis current enables automatic recovery after fault. |
| AGND (6) | Analog ground reference | Star-ground node for COMP, CSH, RCT, TIMR; tied to PGND only through DAP to isolate analog and power paths. |
Key Features
| Feature | Design Value |
|---|---|
| Predictive Off-Time (PRO) Control | Eliminates sub-harmonic oscillation at all duty cycles; simplifies loop compensation and enables stable >50% duty operation in boost topologies. |
| High-Side Differential Current Sense | HSP/HSN inputs support floating LED strings; 20 mA/V transconductance and 11.5 µA input bias enable ±1% ILED accuracy with proper resistor matching. |
| Integrated Dimming Drivers | Dual independent outputs: GATE (1-A peak) for main switch + DDRV (3.5 Ω sink) for dedicated dimming FET - enabling flicker-free 1000:1 PWM dimming. |
| Wide Input Voltage Range | 4.5–75 V operation covers 12 V automotive, 24 V industrial, and 48 V telecom rails - no external HV pre-bias needed. |
| Robust Protection Suite | Includes input UVLO, output OVP, cycle-by-cycle current limit, thermal shutdown (165°C), and zero-current shutdown via RPD pin. |
Applications
| Automotive Front Lighting | Industrial Area SSL |
|---|---|
|
Use Scenario: High-brightness LED headlamps requiring precise current regulation across battery voltage swings (9–16 V) and ambient temperatures (−40°C to +125°C). IC Role / Device Role / Timing Role: N-channel controller implementing boost topology to drive 3–9 series HBLEDs; PRO control maintains stable 200–1500 mA output despite input ripple. Use Value: AEC-Q100 Grade 0 qualification ensures reliability; 75 V absolute max rating accommodates load dump transients up to 60 V. |
Use Scenario: Outdoor parking lot luminaires powered from 24 V DC or PoE++ infrastructure, operating continuously in −40°C to +85°C environments. IC Role / Device Role / Timing Role: Buck-boost controller regulating constant 700 mA LED current while accepting variable input (18–36 V); RCT-programmed 600 kHz switching minimizes EMI. Use Value: High-side sensing isolates LED string from ground faults; thermal shutdown prevents thermal runaway during extended operation. |
| Commercial Architectural Lighting | UV-C Disinfection Systems |
|
Use Scenario: Tunable-white LED fixtures requiring smooth 0–100% analog dimming and synchronized PWM dimming for DALI-2 compatibility. IC Role / Device Role / Timing Role: Dual-dimming interface: CSH pin accepts 0–10 V analog signal; nDIM accepts 200 Hz PWM - both independently modulate ILED without affecting regulation stability. Use Value: 1.24 V CSH reference enables <±2% dimming linearity; DDRV output drives external P-channel dim FET for zero-crossing dimming. |
Use Scenario: Pulsed UV-C LED arrays (275 nm) demanding precise 1.2 A constant current with rapid on/off cycling to manage thermal stress and dose control. IC Role / Device Role / Timing Role: Boost controller with IS-based cycle-by-cycle limiting ensures instantaneous current cutoff during pulse edges; PRO control enables 1.5 MHz operation for tight pulse width control. Use Value: 2.2 ns propagation delay from IS fault to GATE shutdown limits energy overshoot; 165°C thermal shutdown prevents LED degradation during duty cycle errors. |
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 |
|---|---|---|---|
| LM3423Q0MH/NOPB | 20-pin HTSSOP; adds FLT flag, TIMR timer, LRDY status, and DPOL polarity control - not present in LM3421Q0MH/NOPB. | Required for designs needing fault latching, LED-ready indication, or P-channel dimming polarity control. | Select LM3423Q0MH/NOPB only if FLT, TIMR, or LRDY signals are required; otherwise LM3421Q0MH/NOPB offers identical core control with smaller footprint. |
| LM3421MH/NOPB | Same 16-pin HTSSOP package and electrical specs, but commercial-grade (−40°C to +125°C) without AEC-Q100 qualification. | Approved for non-automotive industrial/commercial lighting where automotive reliability testing is not mandated. | Choose LM3421MH/NOPB for cost-sensitive non-automotive applications; LM3421Q0MH/NOPB is mandatory for Grade 0 automotive deployment. |
Compared with LM3423Q0MH/NOPB, LM3421Q0MH/NOPB saves board space and BOM cost where fault flags and status outputs are unnecessary; versus LM3421MH/NOPB, it adds AEC-Q100 Grade 0 validation for under-hood automotive use - making it the sole choice for safety-critical front lighting systems.
Availability
LM3421Q0MH/NOPB is available at Aetrix Electronics and suitable for automotive front lighting, industrial area SSL, and UV-C disinfection systems requiring stable component supply with full AEC-Q100 Grade 0 compliance and long-term production continuity.
Supply support for LM3421Q0MH/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 leader specializing in analog, embedded processing, and power management ICs, with decades of automotive-grade product development and manufacturing excellence.
The LM342x family was designed specifically for high-reliability constant-current LED driver applications in harsh environments - emphasizing wide-input operation, predictive control stability, and integrated protection for automotive and industrial lighting.
FAQ
What is the AEC-Q100 qualification grade for LM3421Q0MH/NOPB?
The LM3421Q0MH/NOPB is qualified to AEC-Q100 Grade 0, meaning it is rated for operation from −40°C to +150°C junction temperature and has passed rigorous automotive reliability stress tests including HTOL, TC, and UHAST. This makes LM3421Q0MH/NOPB suitable for under-hood automotive LED lighting applications where extreme thermal and electrical stress is expected.
How does the predictive off-time (PRO) control in LM3421Q0MH/NOPB differ from standard peak current mode?
Unlike standard peak current mode, which can suffer sub-harmonic oscillation above 50% duty cycle, LM3421Q0MH/NOPB uses predictive off-time (PRO) control - combining peak current sensing with an input-voltage-proportional one-shot off-timer. This eliminates instability at any duty cycle, simplifies loop compensation, and enables robust boost operation even with wide VIN/VO ratios - a key advantage confirmed in TI's SNVS574G documentation.
Can LM3421Q0MH/NOPB support both PWM and analog dimming simultaneously?
No - LM3421Q0MH/NOPB supports either PWM dimming (via nDIM pin) or analog dimming (via CSH pin), but not both simultaneously. The CSH pin is internally regulated to 1.24 V for analog current scaling, while nDIM accepts logic-level PWM signals for digital intensity control. Using both concurrently would conflict with the error amplifier's regulation target and is not supported per TI's functional description in section 8.3.4.
What is the purpose of the RPD pin on LM3421Q0MH/NOPB?
The RPD (Resistor Pulldown) pin on LM3421Q0MH/NOPB provides a controlled low-impedance path to ground for all external resistor dividers connected to nDIM (UVLO) and OVP pins. When EN is low, RPD activates to pull those dividers to AGND, ensuring true zero-current shutdown - preventing leakage-induced false enable or OVP latch-up. Its typical pulldown resistance is 145 Ω at 25°C.
Does LM3421Q0MH/NOPB include an integrated LED current limit, or is it externally set?
LM3421Q0MH/NOPB does not impose a fixed maximum LED current - it is a controller, not a driver IC. LED current is fully determined by external components: the RSNS sense resistor value, the RHSP/RCSH network setting the CSH reference, and system topology. However, it does provide cycle-by-cycle current limiting via the IS pin with a 245 mV threshold, protecting the main switch during fault conditions regardless of programmed ILED.
LM3421Q0MH/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 16-PowerTSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- 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:
- 3V ~ 72V
- Current - Output / Channel:
- -
- Frequency:
- 2MHz
- Dimming:
- Analog, PWM
- Applications:
- -
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-HTSSOP
LM3421Q0MH/NOPB FAQ
1.How can I place an order for LM3421Q0MH/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3421Q0MH/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 LM3421Q0MH/NOPB reliable?
The price and inventory of LM3421Q0MH/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3421Q0MH/NOPB is usually 5 days.
3.What payment methods are accepted for LM3421Q0MH/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3421Q0MH/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3421Q0MH/NOPB?
LM3421Q0MH/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3421Q0MH/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 LM3421Q0MH/NOPB?
For technical support, including LM3421Q0MH/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3421Q0MH/NOPB requirements.
6.How does Aetrix verify that LM3421Q0MH/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3421Q0MH/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 LM3421Q0MH/NOPB meets industry standards.
7.What is the process for return or replacement of LM3421Q0MH/NOPB?
All LM3421Q0MH/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3421Q0MH/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 LM3421Q0MH/NOPB part is unused and in its original packaging.
Return procedure for LM3421Q0MH/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM3421Q0MH/NOPB Tags
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BCR402RE6327HTSA1
Infineon Technologies
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BCR430UXTSA2
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BCR420UE6433HTMA1
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BCR420UE6327HTSA1
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BCR421UE6327HTSA1
Infineon Technologies
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LYT1604D-TL
Power Integrations
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HV9910CLG-G
Microchip Technology
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CL2N8-G
Microchip Technology
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BCR420UW6-7
Diodes Incorporated
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BCR421UW6-7
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BCR420UFD-7
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BCR421UFD-7
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