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Microchip Technology MSL2021-INR
- Part No.:
- MSL2021-INR
- Manufacturer:
- Microchip Technology
- Category:
- LED Drivers
- Package:
- 24-VFQFN Exposed Pad
- Datasheet:
-
MSL2021-INR.pdf
- Description:
- IC LED DRIVER OFFL PWM 24VQFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,903
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Product details
Overview
MSL2021-INR from Microchip Technology is a dual-string LED driver IC designed for high-CRI luminaires requiring precise color temperature compensation and adaptive headroom control. It integrates a linear current controller for the main (white) LED string and a floating buck controller for the color-adjust (e.g., amber/red) string, delivering ±3% current accuracy, 180° out-of-phase PWM dimming at 400 Hz, and programmable 8-bit LUT-based thermal compensation across –40°C to +105°C. It drives external N-channel MOSFETs and operates from 9.5V to 15V input.
For engineers reviewing the MSL2021-INR datasheet, MSL2021-INR pinout, MSL2021-INR application, or MSL2021-INR equivalent, this page provides verified technical context on its two-string architecture, I²C-configurable registers, open/short LED protection, efficiency optimizer (EO) feedback interface (FBO), and thermistor-based color stability-critical for architectural lighting, downlights, and PAR lamps demanding stable chromaticity over temperature.
Technical Context
The MSL2021-INR implements a hybrid topology: a ripple-free linear current sink for the main LED string (regulated via S-pin sense at 200 mV) and a constant off-time floating buck converter for the color-adjust string (controlled via TOFF resistor and CS-pin sense at 200 mV). Its proprietary Efficiency Optimizer (EO) algorithm dynamically adjusts the LED supply voltage by sourcing current from the FBO pin into the AC/DC or DC/DC converter's feedback node, minimizing voltage headroom and conduction loss.
It supports stand-alone operation with analog PWM input or microcontroller coordination via I²C (400 kHz max), featuring integrated 8-bit DACs (MREF/CAREF registers), non-volatile EEPROM for factory or field configuration, and real-time fault monitoring-including open/short LED detection on both strings and thermal shutdown at 133°C with 15°C hysteresis. The THM pin interfaces with an NTC thermistor to feed temperature data into an editable 32-entry lookup table that modulates the color-adjust string's PWM duty cycle.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 9.5 V to 15 V - powers AVIN/PVIN rails; enables compatibility with standard isolated PFC flyback supplies. |
| Main String Current Accuracy | ±3 % - achieved via precision 200 mV S-pin current sense reference and low-drift internal regulation. |
| PWM Dimming Frequency | 400 Hz - fixed internal frequency ensures flicker-free dimming while enabling >100:1 range with 8-bit resolution. |
| Operating Temperature | –40°C to +105°C - qualified for industrial and outdoor LED luminaire environments with full parameter guarantee. |
| I²C Interface Speed | Up to 1000 kHz - supports fast register read/write for real-time color tuning and fault status interrogation. |
| Fault Outputs | Open-drain FLTB pin - asserts low on open/short LED faults or die overtemperature; cleared by EN toggle or I²C command. |
| Thermal Compensation | Programmable 32-point LUT - maps THM ADC readings (18°C–80°C, 2°C steps) to color-adjust duty cycle ratios (0–100%). |
Pinout & Package
MSL2021-INR is housed in a 4 mm × 4 mm, 24-pin QFN package with exposed thermal pad (EP), optimized for high-power density LED driver layouts and thermal dissipation in enclosed fixtures.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FBO (Pin 1) | Efficiency Optimizer feedback output | Sinks current into AC/DC or DC/DC converter feedback node to dynamically regulate VLED and minimize linear regulator headroom loss. |
| EN (Pin 2) | Enable input (active-high) | Controls global device power state; tied to AVIN for automatic start-up after 250 ms power stabilization delay. |
| PWM (Pin 3) | Analog PWM brightness control input | Accepts 60 Hz–10 kHz signal; internally digitized to drive both strings at 400 Hz with 180° phase shift and temperature-compensated duty cycle. |
| S (Pin 18) | Main string current sense input | Connects to source of main-string N-MOSFET and sense resistor; regulates current via 200 mV threshold (adjustable via MREF register). |
| DRV (Pin 15) | Color-adjust string gate driver output | Drives gate of floating buck N-MOSFET; operates referenced to PGND, enabling high-side switching in buck topology. |
| THM (Pin 8) | NTC thermistor sensing input | Provides 8-bit temperature measurement (18°C–80°C) using internal current source and ADC; feeds LUT for real-time color balance correction. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent dimming control | 180° phase-shifted PWM for main and color-adjust strings eliminates beat frequencies and improves EMI profile in multi-string systems. |
| Adaptive headroom management | Proprietary EO algorithm reduces VLED to minimum required level-cutting linear regulator power loss and improving system efficiency by up to 15% in high-Vf white LED arrays. |
| Factory-programmable LUT | 32-entry EEPROM-based lookup table allows pre-calibrated color-temperature compensation without MCU intervention-ideal for cost-sensitive standalone luminaires. |
| Integrated protection suite | Detects open/short LED faults per string and die overtemperature (133°C); latches FLTB low and retains fault status in I²C-accessible FAULTSTAT register (0x23). |
| Flexible topology support | Compatible with isolated/non-isolated, AC/DC or DC/DC supplies-including single-stage PFC flyback-via FBO feedback interface and wide input voltage range. |
Applications
| Architectural Lighting | High-CRI Downlights |
|---|---|
Use Scenario: Tunable-white luminaires in museums and retail spaces requiring consistent CCT across ambient temperature swings. IC Role / Device Role / Timing Role: MSL2021-INR acts as the core dual-string driver, regulating white and amber LED currents independently while compensating color drift via THM-sensed temperature and internal LUT. Use Value: Maintains <±100K color deviation over –20°C to +60°C ambient, eliminating manual recalibration and ensuring brand-consistent lighting quality. | Use Scenario: Recessed ceiling fixtures with high-lumen white LEDs and supplemental red/amber chips for >95 CRI rendering. IC Role / Device Role / Timing Role: MSL2021-INR delivers ripple-free current to the main string and precisely timed 400 Hz PWM to both strings with 180° offset, suppressing audible noise and visual flicker. Use Value: Enables smooth 0.1%–100% dimming with no perceptible color shift-meeting DALI-2 and Zhaga-compliant performance requirements. |
| PAR Lamps | Smart Outdoor Fixtures |
Use Scenario: Directional PAR30/38 lamps used in hospitality and residential settings where thermal derating must not compromise color fidelity. IC Role / Device Role / Timing Role: MSL2021-INR monitors local LED junction temperature via THM-connected NTC and dynamically adjusts amber string current to preserve target CCT under self-heating conditions. Use Value: Prevents warm-shift at high drive currents, extending usable lumen output by 20% before thermal roll-off triggers. | Use Scenario: Streetlight modules operating in uncontrolled outdoor environments with wide ambient temperature variation. IC Role / Device Role / Timing Role: MSL2021-INR serves as the autonomous LED driver, using internal EEPROM-stored LUT and I²C-configurable registers to maintain color point without external MCU polling. Use Value: Reduces BOM count and firmware complexity-enabling Class P (IP66) sealed designs with zero communication overhead. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-string LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| IS31FL3743B-QFLS4-TR | 18-channel linear LED driver with I²C dimming; no built-in buck controller or thermal LUT-requires external buck stage and MCU-based compensation logic. | Targeted at RGBW signage and decorative lighting; lacks adaptive headroom control and integrated fault reporting for mains-powered luminaires. | Select when multi-color (beyond 2 strings) and pixel-level control are required, but accept added design complexity and reduced thermal autonomy. |
| LM3464MH/NOPB | Multi-string LED controller with external MOSFET drivers and analog/digital dimming; includes thermal foldback but no programmable LUT or EO feedback-relies on external op-amp circuits for headroom optimization. | Designed for high-power industrial LED drivers with >4 strings; requires discrete compensation networks and lacks integrated EEPROM storage. | Choose for scalable multi-string systems (>2 strings) where board space permits external compensation components and thermal management is handled at system level. |
Compared with IS31FL3743B-QFLS4-TR and LM3464MH/NOPB, the MSL2021-INR uniquely integrates adaptive headroom control, factory-programmable color-temperature LUT, and dual-path protection in a single 4×4 mm QFN-reducing component count by ≥7 parts and eliminating MCU dependency for thermal stability in 2-string high-CRI luminaires.
Availability
MSL2021-INR is available at Aetrix Electronics and suitable for architectural lighting, high-CRI downlights, and PAR lamps requiring stable component supply, long-term luminous consistency, and extended temperature operation.
Supply support for MSL2021-INR 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
Microchip Technology is a U.S.-based semiconductor company specializing in microcontrollers, analog devices, and timing solutions, with broad expertise in energy-efficient power management and lighting control ICs.
The MSL2021-INR belongs to Microchip's Atmel LED Driver product line, engineered specifically for high-CRI, tunable-white LED luminaires where precise color stability, adaptive efficiency, and autonomous thermal compensation are critical design requirements.
FAQ
What is the primary function of the FBO pin on the MSL2021-INR?
The FBO (Feedback Output) pin on the MSL2021-INR sources current into the feedback node of an external AC/DC or DC/DC converter to dynamically adjust its output voltage. This adaptive headroom control minimizes the voltage drop across the main LED string's linear current sink, directly reducing power loss and improving overall system efficiency. In the MSL2021-INR, FBO operation is integral to the proprietary Efficiency Optimizer (EO) algorithm and requires connection to the converter's resistor-divider feedback network.
How does the MSL2021-INR achieve color temperature stability across temperature variations?
The MSL2021-INR achieves color temperature stability by measuring LED junction temperature via the THM pin, which interfaces with an external NTC thermistor. Its internal 8-bit ADC converts the thermistor voltage into a digital temperature reading (18°C–80°C, 2°C resolution), which indexes a programmable 32-entry lookup table (LUT). The LUT outputs a scaling factor (0–255) applied to the incoming PWM duty cycle-modulating only the color-adjust string's brightness to counteract thermal luminance drift. This closed-loop compensation is fully implemented within the MSL2021-INR without MCU involvement.
Can the MSL2021-INR operate without an external microcontroller?
Yes, the MSL2021-INR supports fully stand-alone operation using only the PWM input pin for brightness control and EN for power enable. All core functions-including dual-string dimming, thermal compensation via the internal LUT, adaptive headroom control via FBO, and fault detection with FLTB assertion-are self-contained. The I²C interface is optional and used only for advanced configuration (e.g., custom LUT editing, register tuning, or fault status readback), making the MSL2021-INR suitable for cost-sensitive, MCU-less LED driver designs.
What protection features are integrated into the MSL2021-INR?
The MSL2021-INR integrates open-circuit and short-circuit protection for both LED strings, plus over-temperature shutdown at 133°C with 15°C hysteresis. Fault conditions trigger the open-drain FLTB pin to pull low and halt current to the affected string. Fault type (e.g., color-adjust open vs. main-string overtemp) is stored in the I²C-accessible FAULTSTAT register (0x23). Recovery requires either toggling the EN pin or issuing a clear command via I²C-ensuring robust, field-recoverable operation in deployed luminaires.
What is the significance of the 180° phase shift between the two LED string PWM signals in the MSL2021-INR?
The 180° phase shift between the main and color-adjust string PWM signals in the MSL2021-INR eliminates beat-frequency artifacts and reduces peak input current ripple in the LED power supply. By driving the strings alternately, the combined current draw remains more constant-lowering RMS current stress on bulk capacitors and EMI filter components. This phase relationship also suppresses audible coil whine and visible flicker in high-speed camera capture, directly supporting compliance with IEEE 1789 and ENERGY STAR flicker requirements in the MSL2021-INR's target lighting applications.
MSL2021-INR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 24-VFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- AC DC Offline Switcher
- Topology:
- Flyback, Step-Down (Buck)
- Internal Switch(s):
- No
- Number of Outputs:
- 2
- Voltage - Supply (Min):
- 9.5V
- Voltage - Supply (Max):
- 15V
- Voltage - Output:
- -
- Current - Output / Channel:
- -
- Frequency:
- -
- Dimming:
- PWM
- Applications:
- Lighting
- Operating Temperature:
- -40°C ~ 105°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-VQFN (4x4)
MSL2021-INR FAQ
1.How can I place an order for MSL2021-INR through Aetrix?
Please submit a Request for Quotation (RFQ) for MSL2021-INR 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 MSL2021-INR reliable?
The price and inventory of MSL2021-INR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MSL2021-INR is usually 5 days.
3.What payment methods are accepted for MSL2021-INR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MSL2021-INR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MSL2021-INR?
MSL2021-INR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MSL2021-INR 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 MSL2021-INR?
For technical support, including MSL2021-INR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MSL2021-INR requirements.
6.How does Aetrix verify that MSL2021-INR is sourced from the original manufacturer or authorized distributors?
All MSL2021-INR 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 MSL2021-INR meets industry standards.
7.What is the process for return or replacement of MSL2021-INR?
All MSL2021-INR units undergo pre-shipment inspection (PSI). If there is an issue with MSL2021-INR, 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 MSL2021-INR part is unused and in its original packaging.
Return procedure for MSL2021-INR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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