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Texas Instruments LM51571RTER
- Part No.:
- LM51571RTER
- Manufacturer:
- Texas Instruments
- Package:
- 16-WFQFN Exposed Pad
- Datasheet:
-
LM51571RTER.pdf
- Description:
- IC REG BOOST FLYBACK ADJ 16WQFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,162
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Product details
Overview
LM51571RTER from Texas Instruments is a wide-input non-synchronous boost/SEPIC/flyback DC-DC controller with integrated 50-V, 45-mΩ N-channel MOSFET. It operates from 2.9 V to 45 V input, delivers up to 48 V output, supports 100 kHz–2.2 MHz programmable switching frequency, and features dual random spread spectrum for EMI reduction - used in battery-powered portable speaker power supplies and industrial holdup capacitor chargers.
For engineers reviewing the LM51571RTER datasheet, LM51571RTER pinout, LM51571RTER application, or LM51571RTER equivalent, key selection criteria include its 4.33-A peak current limit, ±1% feedback reference accuracy, hiccup-mode overload protection, and 16-pin 3 mm × 3 mm WQFN package with exposed thermal pad.
Technical Context
The LM51571RTER implements peak-current-mode control with an internal transconductance error amplifier (2 mA/V Gm) and programmable soft-start via external capacitor. Its RT pin sets switching frequency from 100 kHz to 2.2 MHz using a single resistor, while MODE pin configures spread spectrum and hiccup-mode protection through precise voltage thresholds (370 mV / 620 mV / >1 V).
It supports three topologies: boost (min 1.5 V input with BIAS ≥ 2.9 V), SEPIC, and primary-side regulated flyback (no optocoupler required). Protection includes overvoltage (110% VREF), line UVLO (1.5 V threshold), thermal shutdown (175°C), and accurate current limiting (4.33 A typical) independent of input voltage.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.9 V to 45 V; enables direct single-cell Li-ion start-up and robust transient tolerance up to 50 V abs max |
| Output Voltage Capability | Up to 48 V; SW pin rated for 50 V absolute maximum, supporting high-voltage bias rails |
| Peak Switch Current Limit | 4.33 A (typ); fixed internal limit ensures consistent inductor sizing across input range |
| Switching Frequency Range | 100 kHz to 2.2 MHz; selectable via RT resistor for AM-band avoidance and compact magnetics |
| Feedback Reference Accuracy | ±1% (0.99–1.01 V); enables precise output regulation without external trimming |
| Shutdown Quiescent Current | ≤2.6 µA; minimizes battery drain in always-on or low-power standby systems |
| Integrated MOSFET RDS(on) | 45 mΩ @ 12 V BIAS; reduces conduction loss and thermal stress in high-current boost stages |
Pinout & Package
LM51571RTER uses a 16-pin WQFN (RTE) package with 3.00 mm × 3.00 mm body size and exposed thermal pad (EP) connected to AGND for enhanced thermal performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 16 PGND | Power ground | Source connection of internal MOSFET; must be low-impedance path to minimize switching noise |
| 2 VCC | VCC regulator output | Supplies internal circuitry and gate driver; requires 5-Ω + 1-µF RC filter to PGND |
| 3 BIAS | High-voltage supply input | Feeds internal VCC regulator; supports 2.9–45 V operation with 50-V transient rating |
| 4 PGOOD | Open-drain power-good indicator | Signals valid output when FB ≥ 90% VREF; requires external pull-up for system sequencing |
| 5 RT | Frequency programming | Resistor-to-AGND sets fSW; internal 0.5-V regulation enables precise frequency control |
| 6 EN/UVLO/SYNC | Multi-function control | Enables device (0.52 V threshold), programs UVLO via divider, or accepts external sync clock |
| 7 AGND | Analog ground reference | Separate from PGND; connects to analog ground plane for error amplifier stability |
| 8 COMP | Error amplifier output | Drives loop compensation network; clamped at 1.1 V (low) / 2.8 V (high) for fault limiting |
| 9 FB | Inverting feedback input | Compares output voltage divider against 1-V reference; determines regulation setpoint |
| 10 SS | Soft-start control | 10-µA current source ramps external capacitor; controls output voltage rise time |
| 11 MODE | Spread spectrum & hiccup mode select | Voltage-programmed (370 mV/620 mV/>1 V) to enable DRSS and/or hiccup protection |
| 12–14 SW | Internal MOSFET drain | High-side switch node; connects to inductor/diode in boost, transformer in flyback |
| 15 NC | No connect | Optional PGND tie for thermal improvement; no internal electrical function |
| EP | Exposed thermal pad | Mandatory connection to AGND plane; reduces θJA by ~12°C/W vs. non-thermal-pad packages |
Key Features
| Feature | Design Value |
|---|---|
| Dual Random Spread Spectrum (DRSS) | Reduces EMI peak amplitude across wide bandwidth using combined triangular + cycle-by-cycle dithering |
| Primary-Side Regulation (Flyback) | Eliminates optocoupler and TL431 in isolated designs via accurate internal reference and current sensing |
| Programmable Hiccup-Mode Overload | Enters 64-cycle off-time after sustained current limit, preventing thermal runaway during short-circuit faults |
| Low-IQ Pulse-Skipping Operation | Maintains >85% efficiency at 10-mA load via adaptive light-load control, extending battery runtime |
| Input Transient Tolerance | Withstands 50-V transients on BIAS pin without latch-up or damage, simplifying front-end protection design |
Applications
| Battery-Powered Portable Speaker | Industrial PLC Power Module |
|---|---|
Use Scenario: Boosts single-cell Li-ion (3.0–4.2 V) to 12–24 V rail for Class-D audio amplifier stage in handheld speakers. IC Role / Device Role / Timing Role: Non-synchronous boost controller managing energy transfer, duty cycle, and current limiting in fixed-frequency PWM mode. Use Value: 2.2-MHz operation enables <10-µH inductors and ceramic output caps, reducing board area by >40% vs. 500-kHz solutions. | Use Scenario: Generates isolated 5 V and 24 V outputs from 24 V DC field bus in programmable logic controller backplane. IC Role / Device Role / Timing Role: Primary-side regulated flyback controller delivering stable outputs without secondary-side feedback components. Use Value: Integrated 45-mΩ MOSFET and ±1% reference eliminate need for external shunt regulator, cutting BOM count by 3 parts. |
| Holdup Capacitor Charger | Piezo Driver Bias Supply |
Use Scenario: Charges 100–470 µF holdup capacitors to 48 V during AC mains interruption in industrial UPS subsystems. IC Role / Device Role / Timing Role: High-voltage boost converter operating in constant-current mode until capacitor reaches target voltage. Use Value: Accurate 4.33-A current limit ensures predictable charge time and prevents inrush overstress on input source. | Use Scenario: Supplies 100–200 V bias to piezoelectric actuators in precision motion control systems requiring fast voltage slewing. IC Role / Device Role / Timing Role: Flyback converter configured for high-ratio step-up with tight output regulation under dynamic load steps. Use Value: 2.2-MHz switching and low 80-ns minimum on-time support rapid 100-V/µs slew rates with minimal dead-time distortion. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar boost/SEPIC/flyback controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM5157RTER | 6.5-A current limit, 48-V max output, 2.2-MHz max fSW | Higher power capability; suited for >15-W boost or multi-output flyback | Select when higher peak current or wider VIN range (up to 45 V) is required |
| LM5122MHX/NOPB | External MOSFET drive, 65-V max input, no integrated switch | Supports >100-W designs with discrete FET selection; lacks spread spectrum | Choose for higher-efficiency, thermally demanding applications where layout control is critical |
Compared with LM5157RTER and LM5122MHX/NOPB, the LM51571RTER trades peak current headroom for smaller solution size and built-in EMI mitigation - making it optimal for space-constrained, battery-operated systems needing reliable 5–20 W output with minimal external components.
Availability
LM51571RTER is available at Aetrix Electronics and suitable for battery-powered portable speakers, industrial PLC power modules, holdup capacitor chargers, and piezo driver bias supplies requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM51571RTER 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-reliability power conversion solutions.
The LM5157x product line targets high-density, low-EMI DC-DC conversion in battery-powered and industrial systems - designed specifically for boost, SEPIC, and primary-side regulated flyback topologies where small footprint and robust transient response are critical.
FAQ
What is the maximum output voltage supported by the LM51571RTER?
The LM51571RTER supports a maximum output voltage of 48 V in boost configuration. Its SW pin has a 50-V absolute maximum rating, allowing safe operation during input transients. This makes the LM51571RTER suitable for applications such as LED bias supplies and industrial holdup capacitor charging where regulated high-voltage rails are required without exceeding device voltage limits.
How does the MODE pin configure spread spectrum and hiccup protection on the LM51571RTER?
The MODE pin on the LM51571RTER selects operating modes via applied voltage during initial power-up: 370 mV enables both dual random spread spectrum (DRSS) and hiccup-mode overload protection; 620 mV enables hiccup mode only; >1 V enables DRSS only. These thresholds correspond to standard resistor dividers (e.g., 37.4 kΩ to AGND), ensuring deterministic startup behavior without external logic.
Can the LM51571RTER operate with input voltage below 2.9 V?
Yes - the LM51571RTER can operate with input supply as low as 1.5 V when the BIAS pin is supplied ≥2.9 V from an auxiliary source (e.g., output rail or external LDO). This capability enables ultra-low-voltage battery operation after initial startup, extending usable capacity in single-cell Li-ion or NiMH systems where main rail drops below 2.9 V.
What is the purpose of the EN/UVLO/SYNC pin on the LM51571RTER?
The EN/UVLO/SYNC pin on the LM51571RTER serves three functions: enabling/disabling the device (threshold = 0.52 V), programming input undervoltage lockout via resistor divider, and accepting external synchronization pulses. When unused, it must be tied to BIAS - floating is prohibited. This multi-function pin reduces external component count while supporting flexible system-level power sequencing and EMI coordination.
Does the LM51571RTER support primary-side regulation in flyback topology without an optocoupler?
Yes - the LM51571RTER supports true primary-side regulation (PSR) in flyback topology using its accurate ±1% internal reference and peak current sensing. It eliminates the need for optocouplers, TL431s, and secondary-side feedback networks by regulating output voltage based on reflected auxiliary winding signals and internal timing, significantly reducing cost and board space in isolated power supplies.
LM51571RTER Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 16-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Up, Step-Up/Step-Down
- Output Configuration:
- Positive
- Topology:
- Boost, Flyback, SEPIC
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.9V
- Voltage - Input (Max):
- 45V
- Voltage - Output (Min/Fixed):
- 1.5V
- Voltage - Output (Max):
- 48V
- Current - Output:
- 4.33A
- Frequency - Switching:
- 100kHz ~ 2.2MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-WQFN (3x3)
LM51571RTER FAQ
1.How can I place an order for LM51571RTER through Aetrix?
Please submit a Request for Quotation (RFQ) for LM51571RTER 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 LM51571RTER reliable?
The price and inventory of LM51571RTER are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM51571RTER is usually 5 days.
3.What payment methods are accepted for LM51571RTER?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM51571RTER transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM51571RTER?
LM51571RTER orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM51571RTER 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 LM51571RTER?
For technical support, including LM51571RTER datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM51571RTER requirements.
6.How does Aetrix verify that LM51571RTER is sourced from the original manufacturer or authorized distributors?
All LM51571RTER 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 LM51571RTER meets industry standards.
7.What is the process for return or replacement of LM51571RTER?
All LM51571RTER units undergo pre-shipment inspection (PSI). If there is an issue with LM51571RTER, 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 LM51571RTER part is unused and in its original packaging.
Return procedure for LM51571RTER:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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