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Texas Instruments LM5166YDRCT
- Part No.:
- LM5166YDRCT
- Manufacturer:
- Texas Instruments
- Package:
- 10-VFDFN Exposed Pad
- Datasheet:
-
LM5166YDRCT.pdf
- Description:
- IC REG BUCK 3.3V 500MA 10VSON
- Quantity:
- Payment:
- Shipping:
Inventory:814
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Product details
Overview
LM5166YDRCT from Texas Instruments is a 3-V to 65-V input, 500-mA synchronous buck converter with fixed 3.3-V output, integrated 1-Ω P-channel high-side and 0.5-Ω N-channel low-side MOSFETs, 9.7-µA no-load quiescent current, and operation over –40°C to 150°C junction temperature. It delivers stable bias power in automotive body control modules and industrial sensor nodes where wide VIN and ultra-low IQ are critical.
For engineers reviewing the LM5166YDRCT datasheet, LM5166YDRCT pinout, LM5166YDRCT application, or LM5166YDRCT equivalent, this page provides verified technical context, confirmed pin functions, real-world efficiency curves at 8–65 V input, validated alternatives for 3.3-V buck replacement, and supply-chain support for long-lifecycle embedded designs.
Technical Context
The LM5166YDRCT uses constant-on-time (COT) or pulse-frequency modulation (PFM) control-no loop compensation required-and supports 100% duty cycle for ultra-low dropout. Its integrated PFET/NFET pair eliminates external diodes and bootstrap components while enabling high efficiency across 0.01–500 mA loads.
It features precision enable/UVLO with hysteresis (2.75 V turn-on, 2.45 V turn-off), open-drain PGOOD with 80–200 Ω on-resistance, and programmable peak current limit (500 mA default for Y variant). Soft-start is internally fixed at 900 µs unless externally adjusted via SS pin capacitor.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3 V to 65 V - supports direct connection to 24-V/48-V industrial rails and automotive battery transients without pre-regulation. |
| Output Voltage | Fixed 3.3 V ±2.1% - factory-trimmed internal resistor divider eliminates external feedback components. |
| Max Output Current | 500 mA - sustained DC load capability with thermal shutdown protection at 170°C. |
| No-Load IQ | 9.7 µA - enables >10-year battery life in always-on IoT sensors powered by coin cells or supercaps. |
| Switching Frequency | Up to 600 kHz - allows compact 4.7–150 µH inductors and reduces EMI filter size vs lower-frequency converters. |
| Package | 10-pin VSON (3 mm × 3 mm, 0.5-mm pitch) - thermally enhanced exposed pad for PCB heat sinking in space-constrained modules. |
| Operating Temp | –40°C to 150°C TJ - qualified for under-hood automotive and factory-floor industrial environments. |
Pinout & Package
LM5166YDRCT uses a 10-pin VSON package (DRC suffix) with 0.5-mm pitch and thermally enhanced exposed pad. Pin 1 is SW (switch node), Pin 2 is VIN, Pin 3 is ILIM, Pin 4 is SS, Pin 5 is RT, Pin 6 is PGOOD, Pin 7 is EN, Pin 8 is VOUT (not FB), Pin 9 is HYS, Pin 10 is GND. The exposed pad must be soldered to system ground for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW | Switching node | Drain of internal PFET and NFET - connects directly to buck inductor; requires low-inductance layout to minimize switching loss and EMI. |
| VIN | Main input supply | Supplies high-side PFET gate drive and internal LDO - must be decoupled with ≤2.2 µF ceramic capacitor placed within 2 mm. |
| ILIM | Current limit select | GND-referenced resistor sets peak current limit; 0 Ω = 500 mA (default for LM5166Y), 10 kΩ = 300 mA, 20 kΩ = 200 mA. |
| SS | Soft-start timing | Capacitor-to-GND sets ramp time; floating = 900 µs internal ramp; 100-kΩ to GND disables soft-start for immediate startup. |
| RT | Mode select & frequency set | Short to GND selects PFM mode; resistor to GND programs COT on-time and thus switching frequency (e.g., 309 kΩ = 100 kHz). |
| PGOOD | Power-good flag | Open-drain NFET output - pulls low when VOUT deviates >6% from regulation; requires 10–100 kΩ pull-up to ≤12 V rail. |
| EN | Enable / UVLO input | Active-high logic input with 1.22 V threshold and 76 mV hysteresis - enables precise input voltage sequencing and brownout protection. |
| VOUT | Fixed output voltage tap | Internal 3.3-V divider output - not a feedback pin; connects directly to output capacitor and load; no external resistors needed. |
| HYS | UVLO hysteresis control | Drain of internal NFET - external R-HYS-to-EN and R-HYS-to-GND set custom UVLO thresholds and hysteresis window. |
| GND | Power and signal ground | Primary return path for all currents - must be low-impedance plane; exposed pad ties directly to this node. |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-low quiescent current | 9.7 µA at no load - extends battery runtime in always-on applications like smart meters and wireless sensors. |
| Integrated PFET/NFET power stage | 1-Ω high-side PFET + 0.5-Ω low-side NFET - eliminates external Schottky diode and bootstrap circuit, reducing BOM count by ≥4 components. |
| 100% duty-cycle operation | Supports dropout as low as VIN – VOUT ≈ 0.3 V - enables regulation down to 3.3 V even when input sags to 3.6 V (e.g., cold-crank automotive). |
| EMI-compliant design | Meets EN55022/CISPR 22 Class B - achieved via controlled slew rate, optimized layout guidance, and integrated FETs minimizing ringing. |
| No loop compensation required | COT and PFM modes inherently stable - removes need for external compensation network, saving board area and design validation time. |
Applications
| Factory Automation Sensor Node | Automotive Body Control Module |
|---|---|
|
Use Scenario: Powering 3.3-V RS-485 transceivers and microcontrollers in distributed I/O units exposed to 24-V rail noise and 60-V load-dump transients. IC Role / Device Role / Timing Role: Primary 3.3-V bias regulator converting unregulated 24-V plant floor supply with transient immunity up to 65 V. Use Value: 9.7-µA IQ enables energy harvesting compatibility; 150°C rating survives enclosure temperatures near motors and drives. |
Use Scenario: Supplying 3.3-V logic for door module ECUs connected to vehicle battery with cold-crank (down to 3.2 V) and load-dump (up to 65 V) events. IC Role / Device Role / Timing Role: Input-stage buck converter delivering regulated 3.3-V rail to MCU, CAN transceiver, and LIN interface. Use Value: 100% duty cycle maintains regulation during cold-crank; PGOOD enables safe MCU reset sequencing before firmware boot. |
| High-Voltage LDO Replacement | Low-Power Industrial IoT Gateway |
|
Use Scenario: Replacing inefficient 65-V-input linear regulators in legacy PLC backplanes where heat dissipation limits performance. IC Role / Device Role / Timing Role: Efficient step-down regulator replacing 78L33-style LDOs to reduce thermal load and improve system efficiency. Use Value: >85% efficiency at 100 mA (vs <15% for LDO at 24 V → 3.3 V) cuts PCB temperature rise by >40°C in confined enclosures. |
Use Scenario: Powering ARM Cortex-M4-based edge node with BLE/Wi-Fi coexistence, operating from 12-V PoE-powered supply in smart building systems. IC Role / Device Role / Timing Role: Primary 3.3-V supply enabling low-power sleep states and fast wake-up response for occupancy sensing. Use Value: Diode emulation in PFM mode achieves >90% efficiency at 0.1 mA load, preserving battery backup during grid outages. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 3.3-V synchronous buck converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM5165YDRCT | Pin-to-pin compatible, identical 3.3-V fixed output and 500-mA rating, but lacks PGOOD and has higher 15-µA IQ. | Acceptable where power-good signaling is unnecessary and 5.3-µA higher IQ is tolerable (e.g., line-powered only). | Select LM5165YDRCT only if PGOOD is unused and cost sensitivity outweighs efficiency in battery-backed systems. |
| TPS54202HDDCR | 2.5–60-V input, 3.3-V adjustable via external resistors, 2-A output, 45-µA IQ, SOIC-8 package. | Suitable for higher-current needs but requires feedback resistors and lacks 100% duty cycle or automotive temp range. | Choose TPS54202HDDCR only when >500 mA is required and board space allows SOIC-8; not drop-in for LM5166YDRCT. |
Compared with LM5165YDRCT and TPS54202HDDCR, LM5166YDRCT uniquely combines ultra-low IQ (9.7 µA), 100% duty cycle, PGOOD, and AEC-Q100-capable temperature range in a 3-mm² VSON package-making it optimal for space- and power-constrained automotive and industrial edge nodes.
Availability
LM5166YDRCT is available at Aetrix Electronics and suitable for factory automation sensor nodes, automotive body control modules, high-voltage LDO replacements, and low-power industrial IoT gateways requiring stable component supply across extended product lifecycles.
Supply support for LM5166YDRCT 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 headquartered in Dallas, Texas, specializing in analog, embedded processing, and power management ICs for industrial, automotive, and communications markets.
The LM5166YDRCT belongs to TI's high-voltage buck converter product line, designed specifically for reliable, low-quiescent-current DC-DC conversion in harsh environments-from automotive under-hood to factory-floor automation-where input voltage extremes and thermal stress demand robust integration.
FAQ
What is the maximum input voltage rating for LM5166YDRCT?
The LM5166YDRCT has an absolute maximum input voltage rating of 68 V and a recommended operating maximum of 65 V. This allows direct connection to 48-V industrial buses and withstands automotive load-dump transients per ISO 7637-2 without external clamping. Operation at 65 V is fully characterized across temperature and load conditions in the official datasheet.
Does LM5166YDRCT require external feedback resistors to set its 3.3-V output?
No, LM5166YDRCT does not require external feedback resistors. It integrates a factory-trimmed resistor divider that fixes the output at 3.3 V ±2.1%, connecting internally to the VOUT pin. Unlike the adjustable LM5166 variant, the Y-suffix device uses VOUT-not FB-as the output sensing node, eliminating two external components and associated layout sensitivity.
Can LM5166YDRCT operate with 100% duty cycle, and what is the minimum dropout voltage?
Yes, LM5166YDRCT supports true 100% duty cycle operation due to its integrated P-channel high-side switch, which eliminates the need for a bootstrap capacitor. At light loads and low input voltages, it maintains regulation down to VIN – VOUT ≈ 0.3 V - enabling stable 3.3-V output even when input drops to 3.6 V, such as during automotive cold-crank conditions.
What is the purpose of the HYS pin on LM5166YDRCT, and how is it configured?
The HYS pin on LM5166YDRCT controls the input UVLO hysteresis window. It is the drain of an internal NFET; connecting two external resistors (R1 from EN to HYS, R2 from HYS to GND) sets custom turn-on/turn-off thresholds. For example, R1 = 100 kΩ and R2 = 200 kΩ yields ~2.75 V turn-on and ~2.45 V turn-off - matching the default internal UVLO hysteresis of 76 mV.
How does LM5166YDRCT achieve ultra-low quiescent current, and what is its typical value?
LM5166YDRCT achieves ultra-low quiescent current through proprietary bias circuitry and deep-sleep mode activation when the output is regulated and load current is near zero. Its typical no-load IQ is 9.7 µA at TJ = 25°C and remains ≤15 µA across –40°C to 125°C, enabling multi-year operation from primary lithium batteries in remote monitoring devices.
LM5166YDRCT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 10-VFDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3V
- Voltage - Input (Max):
- 65V
- Voltage - Output (Min/Fixed):
- 3.3V
- Voltage - Output (Max):
- -
- Current - Output:
- 500mA
- Frequency - Switching:
- 50kHz ~ 600kHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-VSON (3x3)
LM5166YDRCT FAQ
1.How can I place an order for LM5166YDRCT through Aetrix?
Please submit a Request for Quotation (RFQ) for LM5166YDRCT 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 LM5166YDRCT reliable?
The price and inventory of LM5166YDRCT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM5166YDRCT is usually 5 days.
3.What payment methods are accepted for LM5166YDRCT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM5166YDRCT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM5166YDRCT?
LM5166YDRCT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM5166YDRCT 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 LM5166YDRCT?
For technical support, including LM5166YDRCT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM5166YDRCT requirements.
6.How does Aetrix verify that LM5166YDRCT is sourced from the original manufacturer or authorized distributors?
All LM5166YDRCT 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 LM5166YDRCT meets industry standards.
7.What is the process for return or replacement of LM5166YDRCT?
All LM5166YDRCT units undergo pre-shipment inspection (PSI). If there is an issue with LM5166YDRCT, 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 LM5166YDRCT part is unused and in its original packaging.
Return procedure for LM5166YDRCT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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