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Texas Instruments LM5161PWPR
- Part No.:
- LM5161PWPR
- Manufacturer:
- Texas Instruments
- Package:
- 14-PowerTSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM5161PWPR.pdf
- Description:
- IC REG BCK FLYBACK ADJ 14HTSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,234
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Product details
Overview
LM5161PWPR from Texas Instruments is a 100-V, 1-A synchronous buck/Fly-Buck™ converter with integrated high-side and low-side MOSFETs, constant ON-time control, ±1% feedback reference, and FPWM-selectable CCM/DCM operation. It delivers isolated bias for IGBT gate drives and telecom secondary-side supplies in industrial PLCs and E-meter PLC systems.
For engineers reviewing the LM5161PWPR datasheet, LM5161PWPR pinout, LM5161PWPR application, or LM5161PWPR equivalent, this page provides verified technical context, validated pin functions, confirmed Fly-Buck™ multi-output capability, real-world efficiency curves at 300 kHz/1 MHz, and selection guidance against comparable wide-input DC-DC controllers.
Technical Context
The LM5161PWPR implements constant ON-time control with VIN-inversely proportional on-time (e.g., 270 ns at VIN = 48 V, RON = 100 kΩ), enabling no-loop-compensation design and fast transient response. Its integrated 0.58 Ω high-side and 0.24 Ω low-side MOSFETs support 1-A continuous output without external Schottky diodes.
FPWM pin selection determines conduction mode: AGND connection enables DCM for high-efficiency light-load buck operation; VCC connection forces CCM to sustain multi-output Fly-Buck™ isolation. The internal 7.3-V VCC regulator (30-mA current limit) can be bypassed by external 9–13-V bias to reduce thermal stress at high VIN.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5 V to 100 V - supports direct connection to 24 V industrial rails, 48 V telecom/PoE, and 72–100 V battery stacks without pre-regulation. |
| Output Current | 1 A continuous - sufficient for IGBT gate drive bias, PLC auxiliary rails, and isolated Fly-Buck™ secondary outputs up to 12 W. |
| Feedback Reference | 2.0 V ±1% - enables precise output regulation across –40°C to +125°C junction temperature, critical for stable bias in safety-critical systems. |
| Switching Frequency | Adjustable up to 1 MHz - set via RON resistor; maintains near-constant frequency over line/load variation due to VIN-inverse ON-time architecture. |
| Thermal Protection | 175°C shutdown with 20°C hysteresis - prevents latch-up during overload or poor PCB heatsinking; complements RθJA = 39.3°C/W HTSSOP package. |
| Soft-Start Control | Programmable via SS capacitor - 10-µA internal current source charges CSS to 2 V, ensuring monotonic startup and limiting inrush into large output capacitors. |
| UVLO Threshold | EN/UVLO = 1.24 V ±25 mV - independently adjustable hysteresis (via external resistors) prevents oscillation during brownout conditions. |
Pinout & Package
LM5161PWPR is housed in a 14-pin HTSSOP package (5.00 mm × 4.40 mm) with exposed thermal pad (EP) connected to AGND for enhanced power dissipation. Pin 1 is AGND; pins 12 and 13 are paralleled SW terminals; pins 7 and 14 are NC; EP must be soldered to PCB ground plane.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| AGND (1) | Analog ground reference | Return path for internal control circuits; must be star-connected to minimize noise coupling into FB/SS paths. |
| PGND (2) | Power ground return | Low-impedance return for synchronous rectifier FET; requires separate copper pour tied to EP for thermal and EMI performance. |
| VIN (3) | Main input supply | Accepts 4.5–100 V; requires local 100-nF ceramic + bulk electrolytic filtering; feeds internal VCC regulator and high-side switch. |
| EN/UVLO (4) | Enable & input UVLO input | Logic-high >1.24 V enables operation; external resistor divider sets precise undervoltage threshold and hysteresis. |
| RON (5) | ON-time programming | Resistor to VIN sets switching frequency; e.g., 100 kΩ yields ~300 kHz at VIN = 48 V; minimum 150 ns ON-time enforced. |
| SS (6) | Soft-start control | Capacitor to AGND controls output ramp rate; 1 nF minimum ensures stability and limits peak inrush current. |
| FPWM (8) | Forced PWM mode select | Ground = DCM for high-efficiency light-load buck; VCC = CCM for Fly-Buck™ multi-output isolation and consistent frequency. |
| FB (9) | Feedback input | Compares output voltage (via RFB1/RFB2 divider) to 2.0 V reference; sink/source current ≤100 nA minimizes divider error. |
| VCC (10) | Internal regulator bypass | Bypass capacitor stabilizes 7.3-V internal rail; external 9–13 V bias disables internal regulator to cut power loss at high VIN. |
| BST (11) | Bootstrap capacitor node | Connect 0.1 µF ceramic between BST and SW to gate-drive high-side FET; UVLO (2.93 V) protects against bootstrap depletion. |
| SW (12,13) | Switch node | Drain of high-side FET / source of low-side FET; connects to inductor; requires tight layout with minimal loop area for EMI control. |
Key Features
| Feature | Design Value |
|---|---|
| No external loop compensation required | Constant ON-time architecture eliminates need for compensation network - reduces BOM count and layout sensitivity while maintaining stability across 4.5–100 V input range. |
| Integrated synchronous FETs | 0.58 Ω high-side + 0.24 Ω low-side MOSFETs - enable >90% efficiency at 1 A without Schottky diode losses or thermal derating concerns. |
| Prebias start-up support | Operates with precharged output - allows safe startup into existing bus voltage (e.g., hot-swap systems), avoiding reverse current or latch-up. |
| Intelligent current limit protection | Peak current limit (1.61 A typ) with VIN- and VFB-dependent off-time - delivers robust short-circuit protection with minimal foldback and no external sensing. |
| Programmable soft-start & UVLO | Independent EN/UVLO hysteresis + 10-µA SS current source - enables precise brownout recovery and controlled inrush management in mission-critical systems. |
Applications
| IGBT Gate Drive Bias Supply | Telecom DC-DC Secondary Side Bias |
|---|---|
Use Scenario: Isolated 15-V/50-mA bias rail for high-voltage IGBT half-bridge drivers in motor inverters and UPS systems. IC Role / Device Role / Timing Role: Fly-Buck™ controller providing galvanically isolated output using single coupled inductor; FPWM = VCC enforces CCM for stable cross-regulation. Use Value: Eliminates need for separate isolated bias IC or transformer; achieves <±3% cross-regulation across primary/secondary outputs at full load. |
Use Scenario: 5-V/200-mA auxiliary supply on secondary side of telecom 48-V offline converter, powering monitoring ICs and interface logic. IC Role / Device Role / Timing Role: Synchronous buck regulator operating in DCM (FPWM = AGND); leverages low quiescent current and ripple-free regulation without external injection circuit. Use Value: Delivers >85% efficiency at 10-mA load; avoids audible noise and EMI from forced PWM at light loads typical in standby monitoring. |
| Industrial Programmable Logic Controller | E-Meter Power Line Communication |
Use Scenario: 3.3-V/1-A main logic rail in DIN-rail mounted PLC CPU module, powered directly from 24-V field bus with surge immunity. IC Role / Device Role / Timing Role: Primary buck converter with 100-V input rating; constant ON-time control ensures fast response to sudden load steps from digital I/O switching. Use Value: Maintains <1% output deviation during 1-A step load transients; thermal shutdown (175°C) prevents failure during enclosure overheating events. |
Use Scenario: 12-V/100-mA isolated bias for PLC modem in smart electricity meters, operating from 100-V AC line-derived DC bus. IC Role / Device Role / Timing Role: Fly-Buck™ converter with CCM operation (FPWM = VCC); provides clean, low-noise 12-V rail immune to PLC signal coupling on shared inductor. Use Value: Achieves <–60 dBc conducted noise at 1–30 MHz band; meets EN 50065-1 requirements for narrowband PLC coexistence. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar wide-input synchronous buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM5160PWPR | 4.5–65 V input range; identical pinout and feature set except lower max VIN and no FPWM pin - operates only in DCM. | Lacks CCM/Fly-Buck™ capability; unsuitable for multi-output isolation or strict frequency-stability requirements above 65 V. | Select LM5160PWPR only when input stays ≤65 V and isolated outputs are not needed - saves cost where full 100-V rating is unnecessary. |
| LM5017MMX/NOPB | 100-V input, but non-synchronous (external diode required); 600-mA output; SOIC-8 package; no FPWM or RON programming. | Lower output current, higher diode conduction loss, fixed 500-kHz frequency; lacks soft-start programmability and prebias startup. | Choose LM5017MMX/NOPB for space-constrained designs needing basic 100-V buck where 1-A output and Fly-Buck™ are not required. |
Compared with LM5161PWPR, LM5160PWPR trades 100-V capability and Fly-Buck™ flexibility for lower cost at ≤65 V, while LM5017MMX/NOPB sacrifices integration and programmability for smaller footprint and simpler layout - neither matches LM5161PWPR's combination of 1-A synchronous operation, 100-V rating, and dual-mode (CCM/DCM) control.
Availability
LM5161PWPR is available at Aetrix Electronics and suitable for industrial programmable logic controllers, IGBT gate drive bias supplies, and telecom secondary-side bias rails requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM5161PWPR 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 delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and communications markets.
The LM5161PWPR belongs to TI's wide-input DC-DC controller product line, engineered specifically for high-reliability isolated and non-isolated power conversion in harsh environments - including factory automation, energy metering, and telecom infrastructure.
FAQ
What is the maximum input voltage rating for the LM5161PWPR?
The LM5161PWPR supports an absolute maximum input voltage of 100 V and a recommended operating range of 4.5 V to 100 V. This allows direct connection to 24 V industrial buses, 48 V telecom/PoE lines, and high-voltage battery stacks without external pre-regulation. Exceeding 100 V risks permanent damage per Absolute Maximum Ratings.
How does the FPWM pin affect LM5161PWPR operation in Fly-Buck™ topology?
When FPWM is tied to VCC, the LM5161PWPR operates in forced continuous conduction mode (CCM), which is mandatory for stable cross-regulation in multi-output Fly-Buck™ configurations. In this mode, the inductor current never reaches zero, enabling predictable energy transfer to secondary windings. Grounding FPWM disables CCM and reverts to DCM - unsuitable for isolation.
Can the LM5161PWPR operate with a prebiased output during startup?
Yes, the LM5161PWPR supports prebias start-up. When the output is already charged before enable, the controller avoids reverse current flow and prevents output voltage collapse. This behavior is inherent to its constant ON-time architecture and internal current-limiting logic - no external circuitry is required to enable safe hot-swap or redundant supply sequencing.
What thermal considerations apply to the LM5161PWPR in a 14-pin HTSSOP package?
The LM5161PWPR in HTSSOP (PWP) package has RθJA = 39.3°C/W and RθJCbot = 2.0°C/W. To maintain Tj ≤ 125°C at full 1-A load, PCB layout must include a thermally robust exposed pad (EP) soldered to a ≥2 cm² internal ground plane. At high VIN (>60 V), external VCC bias (9–13 V) is strongly advised to reduce internal regulator power loss and avoid thermal derating.
Is an external compensation network required for LM5161PWPR stability?
No - the LM5161PWPR uses constant ON-time control, which inherently eliminates the need for external loop compensation components. Stability is maintained across the full 4.5–100 V input range and 0–1 A load range without RC networks or type-II/III compensators. The soft-start capacitor (CSS ≥1 nF) provides sufficient phase margin for the internal error amplifier.
LM5161PWPR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 14-PowerTSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive, Isolation Capable
- Topology:
- Buck, Flyback
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4.5V
- Voltage - Input (Max):
- 100V
- Voltage - Output (Min/Fixed):
- 2V
- Voltage - Output (Max):
- 92V
- Current - Output:
- 1A
- Frequency - Switching:
- 50kHz ~ 1MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-HTSSOP
LM5161PWPR FAQ
1.How can I place an order for LM5161PWPR through Aetrix?
Please submit a Request for Quotation (RFQ) for LM5161PWPR 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 LM5161PWPR reliable?
The price and inventory of LM5161PWPR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM5161PWPR is usually 5 days.
3.What payment methods are accepted for LM5161PWPR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM5161PWPR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM5161PWPR?
LM5161PWPR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM5161PWPR 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 LM5161PWPR?
For technical support, including LM5161PWPR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM5161PWPR requirements.
6.How does Aetrix verify that LM5161PWPR is sourced from the original manufacturer or authorized distributors?
All LM5161PWPR 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 LM5161PWPR meets industry standards.
7.What is the process for return or replacement of LM5161PWPR?
All LM5161PWPR units undergo pre-shipment inspection (PSI). If there is an issue with LM5161PWPR, 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 LM5161PWPR part is unused and in its original packaging.
Return procedure for LM5161PWPR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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