My Inquiry
My Account
STMicroelectronics L99LD01
- Part No.:
- L99LD01
- Manufacturer:
- STMicroelectronics
- Category:
- LED Drivers
- Package:
- 32-LQFP
- Datasheet:
-
L99LD01.pdf
- Description:
- IC LED DRVR CTRL PWM 50MA 32LQFP
- Quantity:
- Payment:
- Shipping:
Inventory:3,896
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
L99LD01 from STMicroelectronics is an automotive-qualified, high-efficiency constant-current DC–DC LED driver in LQFP32™ package, supporting Boost, Buck-Boost, and Flyback topologies. It delivers precise LED current regulation (±1% typical), programmable 100–500 kHz switching frequency via RSF resistor, integrated 5 V ±2% micro supply (20 mA), and SPI-controlled diagnostics for headlamp systems.
For engineers reviewing the L99LD01 datasheet, L99LD01 pinout, L99LD01 application, or L99LD01 equivalent, this device supports critical automotive lighting functions including PWM dimming, battery overvoltage shutdown (via R3/R4), LED chain OV detection (R5/R6), NTC-based temperature monitoring, and limp-home mode recovery-requiring accurate current control, thermal safety, and EMC-compliant spread-spectrum operation.
Technical Context
The L99LD01 integrates a current-mode PWM controller with internal slope compensation (adjustable via SC pin resistor) and a random dither oscillator to reduce conducted/EMI emissions across 100–500 kHz. Its dual gate drivers (G1/G2) support external PMOS switches in high-side configurations, while the analog multiplexer on MOUT enables time-shared monitoring of LED voltage, NTC temperature, and low-frequency PWM signals.
SPI interface (SDI/SDO/SCK/CSN) provides full register access for real-time configuration of LED current reference (±66.7%), input current limit (±55.5%), dither modulation depth/frequency, and fault status reporting. The device implements hardware-level protections including battery overvoltage shutdown (INP_OV), LED chain overvoltage detection (VLED), thermal shutdown, watchdog timer, and power-on reset (NRES).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 5.6 V to 24 V VBATT - supports full automotive battery range including cold-crank (5.6 V) and load-dump (up to 40 V absolute max) |
| LED Current Accuracy | ±1% typical - enables tight brightness consistency across LED strings in headlamps without calibration |
| Switching Frequency | 100–500 kHz adjustable via RSF resistor - allows EMI optimization and inductor size trade-off |
| Regulated Micro Supply | 5 V ±2% @ 20 mA - powers external MCU or sensors without additional LDO |
| Current Sense Inputs | ISENSE+ / ISENSE− differential pair - rejects common-mode noise for stable current regulation in noisy automotive environments |
| Thermal Protection | Internal thermal shutdown with hysteresis - prevents damage during sustained overtemperature conditions |
| EMC Reduction | Internal spread-spectrum dither oscillator - spreads switching spectrum to lower peak radiated emissions |
Pinout & Package
L99LD01 is housed in a 7×7 mm LQFP32™ package with exposed thermal pad (ECOPACK® compliant), optimized for automotive PCB thermal management and reflow compatibility.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VCC1 | 5 V regulator output | Supplies external microcontroller; requires 10 µF ceramic capacitor for stability |
| NRES | Reset I/O (open-drain) | Active-low reset signal for MCU; asserts when VCC1 drops below threshold or during startup failure |
| PWM_L | Low-frequency PWM input | Enables analog-style dimming at frequencies down to 100 Hz; tolerant to logic-level signals |
| SDI/SDO/SCK/CSN | SPI serial interface | Full-duplex communication for register read/write; supports ST SPI standard with command byte addressing |
| MOUT | Multiplexed analog output | Time-shared output for LED voltage (VLED), NTC temperature, or PWM signal - selected via SPI command |
| G1/G2 | PMOS gate drivers | High-side drivers capable of driving external PMOS switches in Boost/Flyback topologies |
| VLED | LED chain overvoltage sense input | Monitors LED string voltage via R5/R6 divider; triggers protection if exceeds programmed threshold |
| SC | Slope compensation adjustment | External resistor sets compensation ramp slope - ensures loop stability across wide duty-cycle range |
Key Features
| Feature | Design Value |
|---|---|
| Automotive qualification | AEC-Q100 Grade 1 (−40 °C to +125 °C ambient) - validated for under-hood headlamp placement |
| SPI-programmable current reference | Adjustable LED current ±66.7% - compensates for LED binning and aging without hardware change |
| Limp-home mode | Dedicated LHM pin triggers safe fallback operation (e.g., reduced brightness) upon fault detection |
| Battery overvoltage protection | Configurable shutdown threshold via R3/R4 - prevents damage during 36 V load-dump transients |
| NTC-based thermal monitoring | Direct NTC connection on NTC pin - enables closed-loop LED temperature derating to extend lifetime |
| Watchdog timer | Programmable timeout with WD_Status bit reporting - detects MCU lockup and initiates recovery |
Applications
| Automotive Daytime Running Lights (DRL) | Adaptive Front-Lighting Systems (AFS) |
|---|---|
|
Use Scenario: Continuous low-power illumination during daylight hours, requiring stable luminance and thermal resilience. IC Role / Device Role / Timing Role: Constant-current driver controlling parallel LED strings; manages thermal foldback via NTC feedback on MOUT. Use Value: Maintains consistent light output across −40 °C to +85 °C ambient with ±1% current accuracy and built-in overvoltage protection against battery transients. |
Use Scenario: Dynamic beam shaping using multiple independently controlled LED zones in headlamps. IC Role / Device Role / Timing Role: Primary LED driver with SPI-configurable current per zone; uses MOUT multiplexing to monitor individual LED voltage/temperature. Use Value: Enables real-time thermal derating and fault isolation per LED segment, improving system reliability and enabling ASIL-B compliance support. |
| LED Headlamp High/Low Beam | Automotive Rear Combination Lamps |
|
Use Scenario: High-brightness main beam operation with PWM dimming for high/low switching and adaptive cutoffs. IC Role / Device Role / Timing Role: High-efficiency Boost driver with G1/G2 gate outputs; PWM_L input synchronizes dimming with vehicle CAN commands. Use Value: Delivers >90% efficiency at 2 A LED current while meeting CISPR-25 Class 5 EMC limits via spread-spectrum dithering. |
Use Scenario: Integrated stop/tail/turn signal module requiring multi-function LED control and diagnostics. IC Role / Device Role / Timing Role: Central driver with limp-home mode (LHM pin) and SPI-reported fault status for functional safety reporting. Use Value: Provides fail-safe operation (e.g., reduced brightness on fault) and diagnostic data via CSN-driven interrupt to body controller. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar constant-current LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX20050ATP/V+ (Maxim) | Integrated MOSFETs (no external PMOS required); fixed 2.2 MHz switching; no spread-spectrum dither | Lower BOM count for mid-power DRL; lacks limp-home mode and MOUT multiplexing | Preferred for space-constrained designs where external FETs are undesirable and EMC requirements are less stringent |
| TLC6C5716RTJR (TI) | 16-channel linear LED driver; no DC–DC conversion; max 5.5 V supply; no SPI programming | Only suitable for low-voltage, low-power interior lighting; cannot replace L99LD01 in Boost/Flyback headlamp topologies | Applicable only for non-automotive or low-power cabin lighting where efficiency and high-side switching are not required |
Compared with MAX20050ATP/V+, L99LD01 offers superior EMC performance and functional safety features (limp-home, watchdog) essential for headlamps, while TLC6C5716RTJR serves entirely different low-voltage linear applications with no topology or protection overlap.
Availability
L99LD01 is available at Aetrix Electronics and suitable for automotive headlamp systems, daytime running lights, and adaptive front-lighting applications requiring stable component supply, AEC-Q100 compliance, and long-term production continuity.
Supply support for L99LD01 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
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, specializing in automotive, industrial, and power management ICs with broad manufacturing and quality certification coverage.
L99LD01 belongs to ST's automotive LED driver product line, engineered specifically for high-reliability exterior lighting systems demanding precision current control, robust fault handling, and seamless integration with vehicle microcontrollers via SPI.
FAQ
What topologies does the L99LD01 support?
The L99LD01 supports Boost, Buck-Boost, and Flyback converter topologies through its dual gate drivers (G1/G2) and current-mode PWM controller. It does not integrate power MOSFETs, so external PMOS devices are required. The device's slope compensation (via SC pin) and wide duty-cycle capability ensure stable operation across all three topologies, as confirmed in Section 7 (Application Circuits) of the datasheet.
How is LED current set and adjusted?
LED current is set by an external sense resistor between ISENSE+ and ISENSE−, with nominal value determining base current (e.g., 10 mΩ → 1 A). It is further adjustable via SPI register programming (±66.7% range) to compensate for LED variance or thermal drift. The current sense path uses differential inputs for noise immunity, and the internal amplifier has <1% gain error over temperature.
Does the L99LD01 include built-in diagnostics?
Yes - it provides comprehensive diagnostics including LED chain overvoltage (VLED pin), battery overvoltage (INP_OV), thermal shutdown, watchdog timeout, and start-up failure detection. Fault status is reported via global status byte accessible over SPI, and the CSN pin can assert low to signal faults to an external MCU. Limp-home mode activation is also detectable via LHM pin state.
What is the role of the MOUT pin?
MOUT is a time-multiplexed analog output that sequentially delivers LED string voltage (VLED), NTC thermistor voltage, or low-frequency PWM signal based on SPI command selection. This enables a single ADC channel on the host MCU to monitor multiple parameters without additional external circuitry, reducing BOM cost and PCB area in space-constrained headlamp modules.
L99LD01 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- 32-LQFP
- Packaging:
- Tray
- Product Status:
- Obsolete
- Type:
- DC DC Controller
- Topology:
- Flyback, Step-Down (Buck), Step-Up (Boost)
- Internal Switch(s):
- No
- Number of Outputs:
- 2
- Voltage - Supply (Min):
- 5.6V
- Voltage - Supply (Max):
- 24V
- Voltage - Output:
- 5V
- Current - Output / Channel:
- 50mA
- Frequency:
- 100kHz ~ 500kHz
- Dimming:
- PWM
- Applications:
- -
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-LQFP (7x7)
L99LD01 FAQ
1.How can I place an order for L99LD01 through Aetrix?
Please submit a Request for Quotation (RFQ) for L99LD01 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 L99LD01 reliable?
The price and inventory of L99LD01 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L99LD01 is usually 5 days.
3.What payment methods are accepted for L99LD01?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L99LD01 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for L99LD01?
L99LD01 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your L99LD01 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 L99LD01?
For technical support, including L99LD01 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L99LD01 requirements.
6.How does Aetrix verify that L99LD01 is sourced from the original manufacturer or authorized distributors?
All L99LD01 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 L99LD01 meets industry standards.
7.What is the process for return or replacement of L99LD01?
All L99LD01 units undergo pre-shipment inspection (PSI). If there is an issue with L99LD01, 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 L99LD01 part is unused and in its original packaging.
Return procedure for L99LD01:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
L99LD01 Tags
-
BCR402RE6327HTSA1
Infineon Technologies
-
BCR430UXTSA2
Infineon Technologies
-
BCR420UE6433HTMA1
Infineon Technologies
-
BCR420UE6327HTSA1
Infineon Technologies
-
BCR421UE6327HTSA1
Infineon Technologies
-
LYT1604D-TL
Power Integrations
-
HV9910CLG-G
Microchip Technology
-
CL2N8-G
Microchip Technology
-
BCR420UW6-7
Diodes Incorporated
-
BCR421UW6-7
Diodes Incorporated
-
BCR420UFD-7
Diodes Incorporated
-
BCR421UFD-7
Diodes Incorporated
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
