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Texas Instruments LM5168FQDDARQ1
- Part No.:
- LM5168FQDDARQ1
- Manufacturer:
- Texas Instruments
- Package:
- 8-PowerSOIC (0.154", 3.90mm Width)
- Datasheet:
-
LM5168FQDDARQ1.pdf
- Description:
- IC REG BUCK ADJ 300MA 8SOPWR
- Quantity:
- Payment:
- Shipping:
Inventory:1,720
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Product details
Overview
LM5168FQDDARQ1 from Texas Instruments is an AEC-Q100 Grade 1 automotive synchronous buck converter delivering up to 0.3-A output current, supporting 6 V to 120 V input range, fixed 3-ms soft-start, FPWM mode for Fly-Buck™ isolated output capability, and integrated 1.9-Ω high-side and 0.71-Ω low-side NFETs. It enables direct 48-V-to-low-voltage conversion in battery management systems.
For engineers reviewing the LM5168FQDDARQ1 datasheet, LM5168FQDDARQ1 pinout, LM5168FQDDARQ1 application, or LM5168FQDDARQ1 equivalent, key selection criteria include its 50 ns minimum on/off time, 3-µA shutdown IQ, FPWM-only operation, hiccup overcurrent protection, and SOIC PowerPAD™ package thermal performance.
Technical Context
The LM5168FQDDARQ1 implements a constant-on-time (COT) control architecture with VIN feed-forward to maintain quasi-fixed switching frequency across 6–120 V input. Its FPWM mode enforces continuous conduction across all loads, enabling stable Fly-Buck™ isolated secondary regulation without diode emulation artifacts.
It integrates both power MOSFETs, internal VCC bias regulator, boot diode, and open-drain PGOOD indicator - eliminating external loop compensation components. Protection includes peak/valley current limiting (0.42 A peak, 0.34 A valley), input UVLO, and thermal shutdown at 175°C with 10°C hysteresis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 6 V to 120 V - supports direct step-down from 48-V nominal or ≥10S battery packs without pre-regulation |
| Output Current | 0.3 A - sufficient for auxiliary rails in BMS, gate drivers, or sensor supplies |
| Switching Frequency | Up to 1 MHz - enables compact magnetics and fast transient response |
| Min On/Off Time | 50 ns - allows >20:1 step-down ratios (e.g., 48 V → 2.5 V) and near-100% duty cycle at low VIN |
| Quiescent Current | < 10 µA in auto mode; 3 µA in shutdown - preserves battery life in always-on vehicle modules |
| Current Limit | 0.42 A peak, hiccup-mode protection - prevents thermal runaway during sustained overload or secondary short in Fly-Buck™ |
| Reference Voltage | 1.2 V ±1.5% - sets output accuracy via external FB divider; stable over –40°C to +125°C ambient |
Pinout & Package
LM5168FQDDARQ1 uses an 8-pin SOIC PowerPAD™ package (4.89 mm × 3.90 mm, 1.27-mm pitch) with exposed thermal pad soldered to PCB ground for enhanced thermal dissipation (RθJB = 14.1°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pin 1) | Ground reference | Common return for internal circuits and thermal pad connection point |
| VIN (Pin 2) | Power input | Connects directly to 6–120 V supply; powers high-side FET and internal VCC regulator |
| EN/UVLO (Pin 3) | Enable & undervoltage lockout | 1.5 V rising threshold enables startup; 1.1 V rising threshold activates standby LDO only |
| RT (Pin 4) | On-time programming | Resistor to GND sets COT pulse width; determines switching frequency in CCM |
| FB (Pin 5) | Feedback input | Compares output voltage (via resistor divider) against 1.2 V reference for regulation |
| PGOOD (Pin 6) | Open-drain status indicator | Asserts low when regulated output deviates >±10%; requires external pull-up |
| BST (Pin 7) | Bootstrap supply | Connects 2.2-nF X7R ceramic capacitor to SW to drive high-side gate |
| SW (Pin 8) | Switching node | Internal connection between high-side drain and low-side source; connects to inductor |
Key Features
| Feature | Design Value |
|---|---|
| FPWM-only operation | Guarantees continuous conduction mode for stable Fly-Buck™ secondary output regulation |
| Integrated power stage | Eliminates external high-side/low-side MOSFETs and gate drivers - reduces BOM count and layout complexity |
| Hiccup overcurrent protection | Disables switching for 64 ms after 16 consecutive current-limit events - protects primary and secondary sides in Fly-Buck™ |
| COT control with no compensation | Enables stable operation with minimal external components - no Type II/III compensator required |
| SOIC PowerPAD™ package | Provides low thermal resistance (RθJB = 14.1°C/W) and HV creepage spacing for 120-V operation |
Applications
| Automotive Battery Management System (BMS) | Industrial High-Cell-Count Battery Pack |
|---|---|
Use Scenario: Regulating auxiliary 3.3-V or 5-V rails from a 48-V or 60-V traction battery stack in HEV/EV BMS modules. IC Role / Device Role / Timing Role: Primary synchronous buck controller providing isolated secondary outputs via Fly-Buck™ for isolated CAN transceivers or cell monitoring ICs. Use Value: Enables single-chip generation of both non-isolated MCU supply and isolated communication rail - reducing component count and board area by >30% vs. discrete solutions. | Use Scenario: Powering telemetry, protection ICs, and display controllers in e-bike or energy storage system (ESS) battery packs with ≥10 series Li-ion cells. IC Role / Device Role / Timing Role: Wide-input buck regulator operating down to 6 V during deep discharge, maintaining regulation while supporting hiccup-mode fault recovery. Use Value: Sustains functionality through full battery voltage range (25 V–60 V), with 3-µA shutdown IQ extending standby runtime by >2× vs. legacy controllers. |
| 48-V Telecom/Industrial Brick Module | Fly-Buck™ Isolated Auxiliary Supply |
Use Scenario: Generating multiple low-voltage rails (e.g., 3.3 V, 5 V, 12 V) in telecom power bricks or industrial PLC backplanes fed from 48-V PoE or DC distribution bus. IC Role / Device Role / Timing Role: Primary buck controller delivering up to 0.3-A load with adjustable frequency (100–1000 kHz) to avoid noise-sensitive bands. Use Value: 50 ns min on-time allows direct 48-V-to-3.3-V conversion (14.5:1 ratio), eliminating intermediate stages and improving efficiency by 8–12%. | Use Scenario: Providing isolated 5-V or 12-V secondary output alongside main buck output using a single transformer and no optocoupler or secondary-side controller. IC Role / Device Role / Timing Role: FPWM-mode buck controller driving Fly-Buck™ topology with precise timing control and hiccup protection for secondary short-circuit resilience. Use Value: Achieves <±5% isolated output regulation without feedback winding or secondary-side regulation - simplifying design and reducing cost by $0.45–$0.70 per unit. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM5168PQDDARQ1 | Auto-mode (PFM/DEM), 0.3-A, no-hiccup current limit | Better light-load efficiency; unsuitable for Fly-Buck™ due to discontinuous conduction | Select when ultra-low IQ (<10 µA) and highest light-load efficiency are prioritized over isolation capability |
| LM5164FQDDARQ1 | 0.6-A, FPWM, 6–100 V input, pin-compatible | Higher output current; same FPWM/Fly-Buck™ support but wider VIN range limited to 100 V | Select when >0.3-A output is required and input stays ≤100 V - maintains identical layout and control scheme |
Compared with LM5168PQDDARQ1, LM5168FQDDARQ1 trades light-load efficiency for Fly-Buck™ compatibility and hiccup protection; compared with LM5164FQDDARQ1, it offers lower cost and 120-V tolerance at reduced current capacity - making it optimal for cost-sensitive, high-VIN automotive auxiliary rails requiring isolation.
Availability
LM5168FQDDARQ1 is available at Aetrix Electronics and suitable for automotive battery management systems, industrial high-cell-count battery packs, 48-V telecom brick modules, and Fly-Buck™ isolated auxiliary supplies requiring stable component supply across extended temperature and voltage ranges.
Supply support for LM5168FQDDARQ1 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 technologies, with deep expertise in automotive-grade reliability and AEC-Q100 qualification.
The LM516x-Q1 product line delivers wide-input, high-voltage synchronous buck converters optimized for HEV/EV power architectures, battery pack auxiliary supplies, and rugged industrial systems demanding 125°C ambient operation and 150°C junction capability.
FAQ
What is the key functional difference between LM5168FQDDARQ1 and LM5168PQDDARQ1?
The LM5168FQDDARQ1 operates exclusively in FPWM mode with hiccup overcurrent protection, enabling Fly-Buck™ isolated output capability and robust short-circuit recovery. In contrast, LM5168PQDDARQ1 uses auto mode (PFM/DEM) for ultra-low quiescent current (<10 µA) but cannot sustain CCM at light loads - making it incompatible with Fly-Buck™ topologies. Both share identical pinout and 0.3-A rating.
Does LM5168FQDDARQ1 support Fly-Buck™ converter operation, and what design requirements does it impose?
Yes, LM5168FQDDARQ1 supports Fly-Buck™ operation via its FPWM mode, which maintains continuous conduction across all load conditions. Required design elements include a coupled inductor (or transformer), 2.2-nF BST capacitor, and careful layout to minimize coupling between SW/BST and FB pins. Minimum on-time must exceed 100 ns for reliable Fly-Buck™ operation - achievable with RT ≥25 kΩ at VIN ≤12 V.
What is the recommended bootstrap capacitor for LM5168FQDDARQ1, and why is value critical?
The LM5168FQDDARQ1 requires a 2.2-nF X7R ceramic capacitor between BST and SW pins. This value is critical because the internal VCC regulator supplies charge to the bootstrap circuit; a larger capacitor increases stress on the regulator and risks damage, while a smaller one may cause high-side gate drive failure during high-duty-cycle operation. TI specifies 2.2 nF as the optimal balance of reliability and gate drive strength.
How does the hiccup overcurrent protection in LM5168FQDDARQ1 behave during a sustained short on the Fly-Buck™ secondary output?
During a sustained secondary short, LM5168FQDDARQ1 detects 16 consecutive current-limit events and enters hiccup mode: it disables switching for 64 ms, then attempts soft-start. If the fault persists, it repeats the cycle. This prevents thermal runaway in both primary and secondary windings and ensures safe recovery once the fault clears - unlike latch-off protection, which would require external reset.
Can LM5168FQDDARQ1 operate reliably at 120-V input, and what layout considerations are essential?
Yes, LM5168FQDDARQ1 is rated for 120-V absolute maximum input and qualified for automotive use up to 115 V recommended operating voltage. Critical layout practices include: 1) short, low-impedance VIN/GND paths with wide copper pours; 2) ≥0.5-mm creepage between VIN/SW and low-voltage pins; 3) grounding the exposed PowerPAD™ to a large thermal plane; and 4) shielding FB traces from SW/BST nodes to prevent instability.
LM5168FQDDARQ1 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-PowerSOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 6V
- Voltage - Input (Max):
- 120V
- Voltage - Output (Min/Fixed):
- 1.2V
- Voltage - Output (Max):
- 120V
- Current - Output:
- 300mA
- Frequency - Switching:
- 100kHz ~ 1MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SO PowerPad
LM5168FQDDARQ1 FAQ
1.How can I place an order for LM5168FQDDARQ1 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM5168FQDDARQ1 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 LM5168FQDDARQ1 reliable?
The price and inventory of LM5168FQDDARQ1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM5168FQDDARQ1 is usually 5 days.
3.What payment methods are accepted for LM5168FQDDARQ1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM5168FQDDARQ1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM5168FQDDARQ1?
LM5168FQDDARQ1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM5168FQDDARQ1 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 LM5168FQDDARQ1?
For technical support, including LM5168FQDDARQ1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM5168FQDDARQ1 requirements.
6.How does Aetrix verify that LM5168FQDDARQ1 is sourced from the original manufacturer or authorized distributors?
All LM5168FQDDARQ1 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 LM5168FQDDARQ1 meets industry standards.
7.What is the process for return or replacement of LM5168FQDDARQ1?
All LM5168FQDDARQ1 units undergo pre-shipment inspection (PSI). If there is an issue with LM5168FQDDARQ1, 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 LM5168FQDDARQ1 part is unused and in its original packaging.
Return procedure for LM5168FQDDARQ1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM5168FQDDARQ1 Tags
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