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Nexperia USA Inc. NCR421ZX
- Part No.:
- NCR421ZX
- Manufacturer:
- Nexperia USA Inc.
- Category:
- LED Drivers
- Package:
- TO-261-4, TO-261AA
- Datasheet:
-
NCR421ZX.pdf
- Description:
- IC LED DRVR LIN PWM 150MA SOT223
- Quantity:
- Payment:
- Shipping:
Inventory:1,084
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Product details
Overview
NCR421ZX from Nexperia is a resistor-equipped NPN transistor-based LED driver IC in SOT223 package, functioning as a digitally controllable constant-current source with PWM dimming capability. It delivers stabilized output current up to 150 mA (adjustable via external resistor), features 1.4 V low voltage overhead, supports enable input up to 4.5 V, and is AEC-Q101 qualified for automotive interior lighting applications.
For engineers reviewing the NCR421ZX datasheet, NCR421ZX pinout, NCR421ZX application, or NCR421ZX equivalent, this page provides verified technical context, real-world design meaning of key specs, validated pin functions, automotive-grade thermal performance data, and confirmed alternative options for constant-current LED driving circuits requiring PWM control and high reliability.
Technical Context
The NCR421ZX integrates an NPN transistor with internal biasing resistors and two diodes on a single die, forming a self-contained current-regulating stage. Its enable pin accepts digital logic-level signals (up to 4.5 V), enabling direct microcontroller interfacing for PWM dimming at frequencies up to 10 kHz.
Current regulation relies on internal resistor feedback and emitter degeneration, delivering ±1% supply voltage sensitivity and –0.27%/K temperature coefficient over –40 °C to +150 °C ambient. The device operates with output voltage headroom as low as 1.4 V while sustaining up to 1250 mW power dissipation on 4-layer FR4 PCBs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Stabilized IOUT | 10 mA (internal resistor only); up to 150 mA with REXT = 5.1 Ω - enables flexible LED string current scaling without redesign. |
| Voltage overhead | 1.4 V minimum - allows operation with short LED strings or low-VF LEDs even at high ambient temperatures. |
| Enable voltage (VEN) | Max 4.5 V - compatible with 3.3 V microcontrollers and logic families without level-shifting. |
| PWM frequency support | Up to 10 kHz - supports flicker-free dimming across human-perceptible brightness ranges. |
| AEC-Q101 qualification | Qualified for automotive use - meets stress testing requirements for interior lighting in dashboards, instrument clusters, and license plate lamps. |
| Power dissipation (PTOT) | 1250 mW on 4-layer FR4 PCB - enables high-current operation without heatsinking in space-constrained automotive modules. |
| Thermal resistance Rth(j-a) | 70 K/W (4-layer PCB, 1 cm² collector pad) - ensures junction temperature stays below 150 °C at 150 mA under typical board conditions. |
Pinout & Package
SOT223 (SC-73) plastic surface-mounted package with increased heatsink; 4 leads. Exposed collector pad serves as primary thermal path and electrical connection.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VEN | Enable input | Digital control pin; active-high logic input accepting 3.3 V CMOS levels; enables/disables output current and supports PWM dimming up to 10 kHz. |
| 2 - REXT | External current-setting resistor terminal | Connects to one end of external resistor; sets output current magnitude (IOUT ≈ 0.95 V / REXT) when VOUT > 2 V. |
| 3 - GND | Ground reference | Common return path for enable circuitry and current-sense node; must be low-impedance for stable regulation. |
| 4 - IOUT | Constant-current output | Emitter output delivering regulated current to LED anode (when used in high-side configuration) or cathode (in low-side sink mode). |
Key Features
| Feature | Design Value |
|---|---|
| No external current-sense resistor required | 10 mA default output set by internal 95 Ω resistor - eliminates BOM cost and layout area for basic indicator applications. |
| Adjustable current range | 10–150 mA via single external resistor - simplifies design iteration across LED types without changing IC footprint. |
| Low thermal drift | –0.27 %/K current variation over temperature - maintains consistent LED brightness across automotive cabin temperature ranges (–40 °C to +85 °C). |
| High supply rejection | ±1 %/V current change over VEN variation - ensures stable illumination despite battery voltage fluctuations (e.g., 9–16 V automotive systems). |
| Parallel operation support | Matched output characteristics allow direct paralleling with identical REXT values - doubles current capacity and power handling without external balancers. |
Applications
| Automotive Interior Lighting | Dashboard Backlighting |
|---|---|
|
Use Scenario: Driving white LED arrays behind analog gauges and digital displays in vehicle instrument clusters. IC Role / Device Role / Timing Role: Constant-current sink regulating 20–100 mA per LED string; enabled via MCU GPIO with 1–10 kHz PWM for brightness control. Use Value: Maintains uniform luminance across temperature (-40 °C to +85 °C) and supply voltage (9–16 V), eliminating visible dimming or color shift during engine cranking or cold starts. |
Use Scenario: Powering edge-lit LCD backlight segments in center console infotainment panels. IC Role / Device Role / Timing Role: High-accuracy current source delivering 30–150 mA per segment; synchronized PWM dimming from vehicle body controller. Use Value: Enables precise grayscale rendering and dynamic contrast adjustment while meeting AEC-Q101 reliability requirements for 15-year automotive service life. |
| License Plate Illumination | LED Status Indicators |
|
Use Scenario: Driving dual-red LED strings mounted in rear license plate housings for regulatory-compliant illumination. IC Role / Device Role / Timing Role: Robust constant-current driver operating from 12 V battery with reverse-polarity protection via external diode; thermally stable at 85 °C ambient. Use Value: Delivers 100 mA per string with <1.4 V overhead, ensuring full brightness even with aged LEDs and elevated underbody temperatures. |
Use Scenario: Providing status indication in industrial control panels using discrete red/green/blue LEDs. IC Role / Device Role / Timing Role: Low-cost, footprint-efficient current regulator replacing discrete transistor-resistor combinations; driven directly from PLC I/O or microcontroller pins. Use Value: Reduces component count by 2–3 parts per LED while maintaining ±5% current accuracy across 0–70 °C industrial ambient range. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar constant-current LED driving applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ON Semiconductor NSI45020AZT1G | Fixed 20 mA output; no enable pin; SOD-123 package; 2.5 V min overhead | Limited to low-current indicators; no PWM dimming; lower thermal mass | Select when only fixed 20 mA is needed and board space is extremely constrained. |
| Diodes Incorporated AL8861Q-13 | Switching buck LED driver; 3–30 V input; adjustable 50–350 mA; requires inductor and diode | Higher efficiency (>90%) at >5 V input; supports longer LED strings; more complex layout | Select for multi-LED strings above 5 V forward voltage or where efficiency >85% is mandatory. |
Compared with NSI45020AZT1G and AL8861Q-13, the NCR421ZX uniquely balances simplicity (no inductor), digital control (PWM-ready enable), and automotive qualification in a thermally robust SOT223 package-making it optimal for mid-current (10–150 mA), space-limited, and temperature-stable LED applications where linear regulation suffices.
Availability
NCR421ZX is available at Aetrix Electronics and suitable for automotive interior lighting, dashboard backlighting, license plate illumination, and industrial LED status indication requiring stable component supply, AEC-Q101 compliance, and thermal resilience.
Supply support for NCR421ZX 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
Nexperia is a global semiconductor expert focused on essential semiconductors for automotive, industrial, and consumer applications, delivering high-reliability discrete and logic devices.
The NCR421ZX belongs to Nexperia's resistor-equipped transistor (RET) LED driver family, designed specifically for robust, low-component-count constant-current driving in automotive lighting and industrial indicator systems.
FAQ
What is the maximum PWM frequency supported by the NCR421ZX?
The NCR421ZX supports digital PWM dimming up to 10 kHz, as specified in its features and benefits section. This enables smooth, flicker-free brightness control across the full 0–100% range without audible noise or visible strobing, validated under standard test conditions (VEN = 3.3 V, Tamb = 25 °C).
Can the NCR421ZX drive multiple LEDs in series?
No-the NCR421ZX is a constant-current sink with a maximum output voltage headroom of 1.4 V. It is designed for single-LED or parallel-LED configurations where total forward voltage remains low. For series strings exceeding ~2.5 V, a higher-headroom driver or switching topology is required.
How does thermal performance change when using different PCB constructions?
Thermal resistance Rth(j-a) varies from 164 K/W (single-layer FR4) to 70 K/W (4-layer FR4 with 1 cm² collector pad). At 150 mA, junction temperature rise drops from ~17°C to ~10°C under identical ambient conditions-directly impacting long-term reliability and current stability.
Is the NCR421ZX pin-compatible with the NCR420Z?
Yes-both share identical SOT223 pinout (VEN, REXT, GND, IOUT) and mechanical footprint. However, NCR420Z has 40 V enable rating and no PWM support, while NCR421ZX uses 4.5 V enable and supports 10 kHz PWM; substituting requires verifying enable voltage compatibility and dimming requirements.
NCR421ZX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Nexperia USA Inc.
- Series:
- -
- Package/Case:
- TO-261-4, TO-261AA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Linear
- Topology:
- Linear
- Internal Switch(s):
- Yes
- Number of Outputs:
- 1
- Voltage - Supply (Min):
- -
- Voltage - Supply (Max):
- 40V
- Voltage - Output:
- 40V
- Current - Output / Channel:
- 150mA
- Frequency:
- -
- Dimming:
- PWM
- Applications:
- -
- Operating Temperature:
- -55°C ~ 150°C (TA)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-223
NCR421ZX FAQ
1.How can I place an order for NCR421ZX through Aetrix?
Please submit a Request for Quotation (RFQ) for NCR421ZX 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 NCR421ZX reliable?
The price and inventory of NCR421ZX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for NCR421ZX is usually 5 days.
3.What payment methods are accepted for NCR421ZX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for NCR421ZX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for NCR421ZX?
NCR421ZX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your NCR421ZX 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 NCR421ZX?
For technical support, including NCR421ZX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your NCR421ZX requirements.
6.How does Aetrix verify that NCR421ZX is sourced from the original manufacturer or authorized distributors?
All NCR421ZX 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 NCR421ZX meets industry standards.
7.What is the process for return or replacement of NCR421ZX?
All NCR421ZX units undergo pre-shipment inspection (PSI). If there is an issue with NCR421ZX, 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 NCR421ZX part is unused and in its original packaging.
Return procedure for NCR421ZX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
NCR421ZX Tags
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CL2N8-G
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