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Texas Instruments LM51571QRTERQ1
- Part No.:
- LM51571QRTERQ1
- Manufacturer:
- Texas Instruments
- Package:
- 16-WFQFN Exposed Pad
- Datasheet:
-
LM51571QRTERQ1.pdf
- Description:
- IC REG BOOST FLYBACK ADJ 16WQFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,905
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Product details
Overview
LM51571QRTERQ1 from Texas Instruments is an AEC-Q100 Grade 1 automotive-qualified, non-synchronous boost/SEPIC/flyback DC-DC controller with integrated 50-V, 4.33-A power MOSFET, 2.2-MHz programmable switching frequency, ±1% feedback reference, and dual random spread spectrum for EMI reduction. It operates from 2.9 V to 45 V input and supports 48-V output in automotive start-stop and LiDAR power supply applications.
For engineers reviewing the LM51571QRTERQ1 datasheet, LM51571QRTERQ1 pinout, LM51571QRTERQ1 application, or LM51571QRTERQ1 equivalent, key selection criteria include peak current limit (4.33 A), BIAS-supplied operation down to 1.5 V input, hiccup-mode overload protection, 45-mΩ RDS(ON), and QFN-16 wettable flanks package compatibility with automotive thermal and layout constraints.
Technical Context
The LM51571QRTERQ1 implements peak-current-mode control with dynamically programmable switching frequency (100 kHz–2.2 MHz via RT resistor) and supports three topologies-boost, SEPIC, and primary-side regulated flyback-without optocoupler. Its internal VCC regulator accepts BIAS input up to 45 V (50-V abs max), enabling robust load-dump tolerance.
It features a precision 1-V reference (±1%), programmable soft-start via external capacitor, PGOOD open-drain indicator, and selectable hiccup-mode protection triggered by sustained overcurrent. Dual random spread spectrum modulation reduces conducted and radiated EMI across wide bandwidths without compromising transient response.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Topology Support | Boost, SEPIC, and primary-side regulated flyback - enables single-chip solutions for battery-backed, isolated, and wide-input automotive rails. |
| Input Voltage Range | 2.9 V to 45 V (with BIAS ≥ 2.9 V); extends to 1.5 V input when BIAS > 2.9 V - supports cold-crank and stop-start battery conditions. |
| Switch Rating | 50-V max drain-source voltage, 4.33-A peak current limit - validated for 48-V output systems with margin against transients. |
| RDS(ON) | 45 mΩ at VBIAS = 12 V - reduces conduction loss and thermal stress in high-current boost stages. |
| Switching Frequency | Programmable 100 kHz to 2.2 MHz via RT resistor - allows AM-band avoidance, compact magnetics, and fast load-transient response. |
| Feedback Reference | 1.00 V ±1% over –40°C to +125°C - ensures stable regulation accuracy across automotive temperature range. |
| EMI Mitigation | Dual random spread spectrum (±7.8% modulation depth) - lowers peak spectral energy across broad frequency span without external components. |
Pinout & Package
LM51571QRTERQ1 is housed in a 3.0 mm × 3.0 mm, 16-pin WQFN package (RTE) with wettable flanks and exposed thermal pad (EP), optimized for automotive PCB assembly and thermal dissipation (RθJA = 45.8°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 16 PGND | Power ground return | Source connection of internal N-channel MOSFET; must be low-inductance path to minimize switching noise and ground bounce. |
| 2 VCC | VCC regulator output | Supplies internal circuitry and gate driver; requires 5-Ω series resistor + 1-µF ceramic cap to PGND for stability. |
| 3 BIAS | High-voltage bias input | Feeds internal VCC regulator; supports 2.9–45 V operation and withstands 50-V transients - critical for load-dump immunity. |
| 4 PGOOD | Power-good indicator | Open-drain output asserting low when FB falls below 90% VREF; requires external pull-up for system sequencing. |
| 5 RT | Frequency programming | Resistor-to-AGND sets fSW from 100 kHz to 2.2 MHz; enables AM-band avoidance and solution size optimization. |
| 6 EN/UVLO/SYNC | Multi-function control | Enables device, programs UVLO threshold, or accepts external sync clock - not left floating; connect to BIAS if unused. |
| 7 AGND | Analog reference ground | Separate low-noise ground for error amplifier and feedback network; must tie to solid analog plane with short trace. |
| 8 COMP | Error amplifier output | Transconductance node (2 mA/V) for loop compensation; connects RC network to AGND for stability tuning. |
| 9 FB | Feedback input | Inverting input of error amp; senses output via resistive divider; accuracy depends on ±1% VREF and layout-sensitive routing. |
| 10 SS | Soft-start control | Capacitor-programmed ramp; internal 10-µA current source sets startup time - prevents inrush and overcurrent during turn-on. |
| 11 MODE | Protection & spectrum mode | Selects hiccup mode and spread spectrum via resistor divider to AGND (e.g., 37.4 kΩ enables both features). |
| 12–14 SW | Power switch drain | Drain node of internal 50-V, 4.33-A MOSFET; carries high di/dt; requires tight layout and Kelvin connection to minimize ringing. |
| 15 NC | No-connect terminal | No internal connection; may be tied to PGND for improved thermal conduction but no electrical function. |
| EP | Exposed thermal pad | Must be soldered to large AGND copper pour for thermal management and EMI shielding - not electrically isolated. |
Key Features
| Feature | Design Value |
|---|---|
| Automotive qualification | AEC-Q100 Grade 1 (–40°C to +125°C TA) - certified for under-hood and infotainment power systems. |
| Primary-side regulation | Integrated error amplifier enables optocoupler-free flyback designs - reduces BOM cost and improves reliability in isolated supplies. |
| Low-power operation | 700 µA operating IQ and ≤2.6 µA shutdown IQ - minimizes battery drain in always-on automotive modules. |
| Transient resilience | Input transient protection up to 50 V and minimum 1.5-V operation with BIAS assist - sustains function during cranking and load dump. |
| EMI compliance support | Leadless WQFN package + dual random spread spectrum - meets CISPR 25 Class 5 requirements without added filtering. |
Applications
| Automotive Start-Stop Voltage Stabilizer | LiDAR High-Voltage Bias Supply |
|---|---|
Use Scenario: Maintains stable 12-V or 24-V rail during engine cranking when battery sags to 6 V. IC Role / Device Role / Timing Role: Non-synchronous boost controller regulating output using BIAS-assisted operation and programmable UVLO. Use Value: Enables uninterrupted operation of ADAS ECUs and cameras without brownout, leveraging 1.5-V minimum input capability and hiccup-mode overload protection. | Use Scenario: Generates 40–48 V bias for laser diode drivers in automotive LiDAR modules. IC Role / Device Role / Timing Role: High-voltage boost converter with 48-V output capability and 2.2-MHz switching for compact transformer design. Use Value: Delivers precise, low-noise high voltage with ±1% reference and spread spectrum - critical for minimizing optical interference and meeting EMC limits. |
| SEPIC Automotive Emergency Call Backup | Piezo Actuator Bias Supply |
Use Scenario: Powers eCall module from degraded 9-V battery during crash event, requiring >12-V output. IC Role / Device Role / Timing Role: SEPIC topology controller supporting buck-boost operation with continuous input-to-output isolation. Use Value: Provides fault-tolerant backup power using single inductor and coupled inductor option - avoids polarity reversal and supports wide VIN/VOUT ratios. | Use Scenario: Supplies fast-switching, low-ripple bias (e.g., ±30 V) for piezo fuel injectors or suspension actuators. IC Role / Device Role / Timing Role: Flyback controller with primary-side regulation and programmable soft-start for controlled voltage ramp. Use Value: Eliminates optocoupler while achieving <1% output accuracy and sub-100-ns timing jitter - essential for precise actuator positioning. |
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 |
|---|---|---|---|
| LM5157QRTERQ1 | Higher 6.5-A peak current limit; identical package, pinout, and feature set - differs only in internal MOSFET rating. | Suitable for higher-output-power boost designs (e.g., >20 W) where 4.33-A limit of LM51571QRTERQ1 is insufficient. | Select LM5157QRTERQ1 when output power or peak inductor current exceeds 4.33 A; otherwise LM51571QRTERQ1 offers optimal cost/performance balance. |
| LM5122QMHXQ1 | Wider 3-V to 75-V input, synchronous rectification, lower 300-µA IQ, but larger HTSSOP-20 package and no spread spectrum. | Better suited for ultra-wide-input industrial or commercial boost converters; lacks automotive EMI mitigation features. | Choose LM5122QMHXQ1 only when input exceeds 45 V or synchronous efficiency is mandatory; LM51571QRTERQ1 remains preferred for AEC-Q100-compliant, EMI-sensitive automotive designs. |
Compared with LM5157QRTERQ1, the LM51571QRTERQ1 trades peak current capacity for tighter thermal and layout constraints in space-constrained modules; versus LM5122QMHXQ1, it delivers superior EMI performance and smaller footprint at the cost of input voltage ceiling and synchronous efficiency.
Availability
LM51571QRTERQ1 is available at Aetrix Electronics and suitable for automotive start-stop systems, LiDAR power supplies, emergency call backup circuits, and piezo actuator biasing requiring stable component supply, AEC-Q100 compliance, and production-ready lead times.
Supply support for LM51571QRTERQ1 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 automotive, industrial, and personal electronics markets.
The LM5157x-Q1 product line was designed specifically for AEC-Q100-compliant DC-DC conversion in automotive battery-connected systems - emphasizing cranking resilience, EMI robustness, and primary-side regulation for isolated topologies.
FAQ
What is the minimum input voltage supported by the LM51571QRTERQ1?
The LM51571QRTERQ1 supports a minimum input voltage of 2.9 V when powered solely from the VSUPPLY pin. However, with the BIAS pin supplied at ≥2.9 V, the device can operate down to 1.5 V on VSUPPLY - a critical capability for automotive cranking conditions. This behavior is enabled by the internal VCC regulator's ability to bootstrap from BIAS, decoupling gate drive from the main input rail.
How does the MODE pin configure spread spectrum and hiccup protection on the LM51571QRTERQ1?
The MODE pin on the LM51571QRTERQ1 selects operating modes via resistor dividers to AGND: 37.4 kΩ enables both hiccup-mode overload protection and dual random spread spectrum; 62.0 kΩ enables hiccup mode only; 100 kΩ enables spread spectrum only; and grounding disables both. These configurations are latched at power-up and determine fault-handling behavior and EMI profile - all settings are validated per TI's characterization data.
Can the LM51571QRTERQ1 be used in flyback topology without an optocoupler?
Yes, the LM51571QRTERQ1 supports primary-side regulation (PSR) in flyback topology using its integrated transconductance error amplifier and accurate 1.00-V ±1% reference. By sensing reflected output voltage across an auxiliary winding, the device eliminates the need for optocoupler and secondary-side TL431, reducing component count, cost, and failure points - confirmed in TI's typical application schematics and AN-2162 design guide.
What is the maximum output voltage achievable with the LM51571QRTERQ1 in boost configuration?
The LM51571QRTERQ1 supports a maximum output voltage of 48 V in boost configuration, constrained by its 50-V absolute maximum switch voltage rating. Exceeding 48 V risks violating the 50-V transient limit at the SW pin during line transients or load steps. TI specifies this limit explicitly in the Device Comparison Table and Absolute Maximum Ratings - design margins must preserve at least 2 V headroom.
Does the LM51571QRTERQ1 support external clock synchronization?
Yes, the LM51571QRTERQ1 supports external clock synchronization via the EN/UVLO/SYNC pin. Applying a negative-going pulse signal within 100 kHz–2.2 MHz range synchronizes the internal oscillator to an external master clock - enabling multi-phase operation and deterministic EMI alignment in complex power systems. This function is electrically isolated from enable and UVLO functions and requires no additional components beyond proper AC coupling.
LM51571QRTERQ1 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):
- 1.5V
- 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 ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-WQFN (3x3)
LM51571QRTERQ1 FAQ
1.How can I place an order for LM51571QRTERQ1 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM51571QRTERQ1 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 LM51571QRTERQ1 reliable?
The price and inventory of LM51571QRTERQ1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM51571QRTERQ1 is usually 5 days.
3.What payment methods are accepted for LM51571QRTERQ1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM51571QRTERQ1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM51571QRTERQ1?
LM51571QRTERQ1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM51571QRTERQ1 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 LM51571QRTERQ1?
For technical support, including LM51571QRTERQ1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM51571QRTERQ1 requirements.
6.How does Aetrix verify that LM51571QRTERQ1 is sourced from the original manufacturer or authorized distributors?
All LM51571QRTERQ1 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 LM51571QRTERQ1 meets industry standards.
7.What is the process for return or replacement of LM51571QRTERQ1?
All LM51571QRTERQ1 units undergo pre-shipment inspection (PSI). If there is an issue with LM51571QRTERQ1, 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 LM51571QRTERQ1 part is unused and in its original packaging.
Return procedure for LM51571QRTERQ1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM51571QRTERQ1 Tags
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