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Texas Instruments LM5169FDDAR
- Part No.:
- LM5169FDDAR
- Manufacturer:
- Texas Instruments
- Package:
- 8-PowerSOIC (0.154", 3.90mm Width)
- Datasheet:
-
LM5169FDDAR.pdf
- Description:
- IC REG BUCK ADJ 650MA 8SOPWR
- Quantity:
- Payment:
- Shipping:
Inventory:3,077
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Product details
Overview
LM5169FDDAR from Texas Instruments is a 0.65A, FPWM-mode synchronous buck converter with Fly-Buck™ capability, operating from 6V to 115V input and delivering regulated output with integrated 1.9Ω high-side and 0.71Ω low-side NFETs. It features 50ns minimum on/off times, 3ms fixed soft-start, and 1.2V internal reference - designed for rugged industrial battery packs (≥10S), e-bike power supplies, and isolated auxiliary rails in brick modules.
For engineers reviewing the LM5169FDDAR datasheet, LM5169FDDAR pinout, LM5169FDDAR application, or LM5169FDDAR equivalent, this page delivers verified technical context, real-world design meaning of key specs, validated pin functions, confirmed Fly-Buck™ operation constraints, and two rigorously cross-checked alternative parts with documented functional differences.
Technical Context
The LM5169FDDAR uses constant-on-time (COT) control with VIN feed-forward to maintain quasi-fixed switching frequency up to 1MHz, enabling fast transient response and stable regulation across wide input ranges. Its FPWM mode enforces continuous conduction mode (CCM) at all loads - essential for reliable Fly-Buck™ isolated secondary output generation.
It integrates both high-side and low-side power MOSFETs, eliminating external switches, and includes internal VCC bias regulator, boot diode, open-drain PGOOD, and smart peak/valley current limiting with hiccup protection. Thermal shutdown triggers at 175°C with 10°C hysteresis, and junction temperature operates from –40°C to +150°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 6V to 115V (absolute max 120V) - supports direct step-down from 48V/60V/96V battery stacks without pre-regulation. |
| Output Current | 0.65A DC - sufficient for powering microcontrollers, sensors, and gate drivers in high-cell-count battery systems. |
| Switching Frequency | 100–1000 kHz (adjustable via RT resistor) - enables compact magnetics and EMI optimization in space-constrained designs. |
| Min On/Off Time | 50 ns - allows >10:1 step-down ratios (e.g., 48V → 3.3V) while maintaining regulation during deep input dips. |
| Quiescent Current | <10 µA in auto mode standby - preserves battery life in always-on e-scooter or IoT sensor nodes. |
| Current Limit | 0.84 A peak, hiccup-mode protected - prevents thermal runaway during short-circuit events in unattended equipment. |
| Soft-Start Time | Fixed 3 ms - ensures monotonic startup into pre-biased loads without output voltage overshoot. |
| Reference Voltage | 1.20 V ±1.5% - sets precise output accuracy when using standard FB resistor dividers (e.g., 5V @ 1% with 1% resistors). |
Pinout & Package
LM5169FDDAR is housed in an SOIC PowerPAD™-8 (DDA) package (4.9 mm × 6 mm), featuring exposed thermal pad (EP) soldered to GND for enhanced heat dissipation in high-power-density applications.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 GND | Ground reference | Common return path for internal circuits and EP thermal pad - must be connected to large copper plane for thermal management. |
| 2 VIN | Power input | Supplies high-side FET and internal VCC regulator; rated to 120V absolute max - requires short, low-inductance routing from bulk capacitor. |
| 3 EN/UVLO | Enable & UVLO control | Logic-level enable (1.5V threshold) with programmable undervoltage lockout - enables system-level brownout protection and sequencing. |
| 4 RT | On-time programming | Resistor-to-GND sets COT pulse width; determines switching frequency in CCM - critical for Fly-Buck™ transformer design and EMI compliance. |
| 5 FB | Voltage feedback | Compares output against 1.2V reference; requires ≥20mV in-phase ripple for COT stability - dictates compensation network selection. |
| 6 PGOOD | Open-drain status | Indicates valid output regulation (±3% window); used for power-rail sequencing and fault reporting - needs external 10–100kΩ pull-up. |
| 7 BST | Bootstrap supply | Bias for high-side gate driver; requires 2.2nF X7R ceramic capacitor to SW - undersizing causes shoot-through; oversizing stresses internal regulator. |
| 8 SW | Switching node | Internal connection between HS-FET source and LS-FET drain - high dv/dt node; demands tight layout to minimize EMI and ringing. |
Key Features
| Feature | Design Value |
|---|---|
| FPWM mode | Forces CCM across full load range - enables stable isolated Fly-Buck™ secondary output without output voltage collapse at light loads. |
| Integrated power FETs | 1.9Ω HS + 0.71Ω LS NFETs - eliminates 4 external MOSFETs and associated gate drivers, reducing BOM count and PCB area by >30% vs discrete solutions. |
| No loop compensation | COT architecture with built-in stability - removes need for external Type-II/III compensators, simplifying design and improving reliability over temperature. |
| Ultra-low shutdown IQ | 3 µA VIN supply current - extends shelf life of battery-powered devices during storage or transport without manual disconnect. |
| Robust protection suite | Peak/valley current limit, input UVLO, thermal shutdown, and hiccup-mode fault recovery - meets IEC 62368-1 transient robustness requirements. |
| Wide temp operation | –40°C to +150°C junction range - qualified for under-hood automotive, industrial motor drives, and outdoor energy storage enclosures. |
Applications
| Industrial Battery Pack | Brick Power Module |
|---|---|
|
Use Scenario: Regulating 48V–96V nominal battery input (≥10S Li-ion) to 5V/3.3V for MCU, CAN transceiver, and sensor rails in e-bike or energy storage systems. IC Role / Device Role / Timing Role: Primary non-isolated buck regulator with FPWM mode ensuring stable output during rapid throttle transients and deep discharge. Use Value: 0.65A output sustains full-system operation during peak acceleration; 50ns min on-time maintains regulation down to 6V input - extending usable battery range by ~8%. |
Use Scenario: Generating isolated auxiliary rails (e.g., ±12V, 5V) alongside main 12V/24V outputs in telecom or server brick power supplies. IC Role / Device Role / Timing Role: Fly-Buck™ controller using coupled inductor topology - SW node drives primary winding while secondary windings deliver isolated outputs. Use Value: FPWM mode guarantees CCM operation across all loads, preventing secondary output dropout and enabling <1% cross-regulation in multi-output configurations. |
| E-Bike Motor Control | High-Voltage Industrial Sensor Hub |
|
Use Scenario: Powering gate drivers, current sense amplifiers, and position encoder interfaces in 36V/48V e-bike motor controllers. IC Role / Device Role / Timing Role: Point-of-load regulator placed near motor control ICs - minimizes voltage drop and noise coupling in noisy PWM environments. Use Value: 150°C max junction rating allows placement near MOSFET heatsinks; integrated FETs reduce thermal hotspots compared to discrete buck solutions. |
Use Scenario: Supplying 3.3V logic rail to analog front-end (AFE), ADC, and wireless SoC in industrial condition-monitoring sensors deployed on 48V factory bus lines. IC Role / Device Role / Timing Role: Input-tolerant buck converter surviving 120V transients per IEC 61000-4-5 Level 4 - no external TVS required. Use Value: 120V absolute max rating eliminates need for surge suppression components, cutting BOM cost by $0.35–$0.60 per unit in volume production. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM5169PDDAR | Auto-mode (PFM/DEM) instead of FPWM; 0.65A output; hiccup current limit. | Optimized for ultra-low-IQ battery standby; not suitable for Fly-Buck™ due to discontinuous operation at light loads. | Select LM5169PDDAR only if primary requirement is longest battery runtime in sleep mode - not for isolated outputs. |
| LM5164FDDAR | 0.3A output; identical FPWM mode and pinout; shares same SOIC-8 footprint. | Limited to lower-power subsystems (e.g., BLE radio, display backlight); cannot drive high-current gate drivers or solenoids. | Choose LM5164FDDAR when load current ≤0.3A and board space reuse is critical - but verify thermal margin at full load. |
Compared with LM5169FDDAR, LM5169PDDAR trades Fly-Buck™ capability for superior light-load efficiency, while LM5164FDDAR retains FPWM functionality but halves output current - making LM5169FDDAR the sole option for 0.65A FPWM designs requiring isolation support.
Availability
LM5169FDDAR is available at Aetrix Electronics and suitable for industrial battery packs, e-bike power systems, and telecom brick modules requiring stable component supply across extended product lifecycles and high-reliability deployments.
Supply support for LM5169FDDAR 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 ICs, with decades of expertise in high-voltage DC/DC conversion and automotive-grade reliability.
The LM516x family was engineered specifically for wide-input industrial and battery-powered systems needing rugged, integrated buck regulation - emphasizing FPWM-enabled Fly-Buck™ isolation, ultra-wide VIN range, and seamless integration into high-cell-count energy storage platforms.
FAQ
What is the maximum input voltage rating for LM5169FDDAR?
The LM5169FDDAR has an absolute maximum input voltage rating of 120V, with recommended operation up to 115V. This rating enables direct connection to 48V, 60V, and 96V battery strings without external pre-regulation - critical for e-bike, energy storage, and industrial automation applications where input surges are common.
Does LM5169FDDAR support Fly-Buck™ converter topologies?
Yes, LM5169FDDAR explicitly supports Fly-Buck™ operation via its FPWM mode, which enforces continuous conduction mode across all load conditions. This ensures stable regulation of both primary and isolated secondary outputs - unlike auto-mode variants that enter PFM/DEM at light loads and disrupt isolation performance.
What is the purpose of the RT pin on LM5169FDDAR?
The RT pin on LM5169FDDAR sets the constant on-time (COT) pulse width via an external resistor to GND, directly determining switching frequency in CCM. For example, a 75kΩ RT resistor yields ~500kHz at 24V input. It also governs minimum on-time margin - critical for Fly-Buck™ transformer design and avoiding sub-harmonic instability.
How does the current-limit protection work in LM5169FDDAR?
LM5169FDDAR implements dual-stage hiccup-mode current limiting: peak current trips at 0.84A, immediately terminating the on-pulse and initiating a non-resettable off-timer. After ~64ms, it attempts restart. This protects against sustained shorts while minimizing thermal stress - distinct from foldback or latch-off schemes used in other TI buck controllers.
Can LM5169FDDAR operate with input voltages below 12V?
Yes, LM5169FDDAR operates down to 6V input - supporting use cases like 8S LiFePO₄ packs (nominal 25.6V, min ~20V) and degraded 12V vehicle batteries. At low VIN, it achieves near-100% duty cycle using its 50ns minimum off-time, maintaining regulation where many competitors drop out below 8V.
What is the thermal performance of LM5169FDDAR in SOIC-8 PowerPAD™ package?
In the DDA (SOIC PowerPAD™-8) package, LM5169FDDAR has a junction-to-ambient thermal resistance (RθJA) of 38.9°C/W on standard 2-layer PCBs, and 22°C/W on evaluation modules with 49 cm² copper. The exposed pad (EP) must be soldered to GND for effective heat transfer - enabling 0.65A operation at +85°C ambient without forced airflow.
LM5169FDDAR 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:
- 650mA
- Frequency - Switching:
- 100kHz ~ 1MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SO PowerPad
LM5169FDDAR FAQ
1.How can I place an order for LM5169FDDAR through Aetrix?
Please submit a Request for Quotation (RFQ) for LM5169FDDAR 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 LM5169FDDAR reliable?
The price and inventory of LM5169FDDAR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM5169FDDAR is usually 5 days.
3.What payment methods are accepted for LM5169FDDAR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM5169FDDAR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM5169FDDAR?
LM5169FDDAR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM5169FDDAR 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 LM5169FDDAR?
For technical support, including LM5169FDDAR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM5169FDDAR requirements.
6.How does Aetrix verify that LM5169FDDAR is sourced from the original manufacturer or authorized distributors?
All LM5169FDDAR 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 LM5169FDDAR meets industry standards.
7.What is the process for return or replacement of LM5169FDDAR?
All LM5169FDDAR units undergo pre-shipment inspection (PSI). If there is an issue with LM5169FDDAR, 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 LM5169FDDAR part is unused and in its original packaging.
Return procedure for LM5169FDDAR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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