My Inquiry
My Account
Texas Instruments LM51581RTER
- Part No.:
- LM51581RTER
- Manufacturer:
- Texas Instruments
- Package:
- 16-WFQFN Exposed Pad
- Datasheet:
-
LM51581RTER.pdf
- Description:
- IC REG BOOST FLYBACK ADJ 16WQFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,922
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LM51581RTER from Texas Instruments is a wide-input non-synchronous boost/SEPIC/flyback controller with integrated 85-V, 1.63-A N-channel MOSFET, 2.2-MHz programmable switching frequency, ±1% feedback reference, and dual random spread spectrum for EMI reduction. It operates from 1.5 V (with BIAS ≥ 3.2 V) to 60-V input and supports up to 83-V output - ideal for battery-powered industrial PLCs and hold-up capacitor charging.
For engineers reviewing the LM51581RTER datasheet, LM51581RTER pinout, LM51581RTER application, or LM51581RTER equivalent, this page delivers verified technical context, validated pin functions, confirmed topology support (boost/SEPIC/flyback), real-world protection features (hiccup-mode OLP, OVP, thermal shutdown), and accurate alternative comparisons - all grounded in TI's SNVSBZ7 production datasheet.
Technical Context
The LM51581RTER implements peak-current-mode control with dynamically programmable switching frequency (100 kHz–2.2 MHz via RT resistor), enabling AM-band avoidance and compact magnetics. Its internal 133-mΩ MOSFET supports high-efficiency operation across wide input ranges, while the BIAS pin (3.2–60 V) powers an integrated VCC regulator that supplies the gate driver and internal circuitry.
It features primary-side regulation capability in flyback topologies via integrated error amplifier and COMP pin, eliminating optocoupler requirements. Protection includes accurate current limiting over input voltage, selectable hiccup-mode overload response, programmable line UVLO, and thermal shutdown at 175°C with 15°C hysteresis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 1.5 V (with BIAS ≥ 3.2 V) to 60 V - enables single-cell Li-ion start-up and robust transient tolerance up to 65 V abs max |
| Max Output Voltage | 83 V (85 V abs max) - supports high-voltage bias rails for LED drivers, piezo actuators, and industrial sensors |
| Switch Current Limit | 1.63 A (typ), 2.12 A (max) - defines maximum inductor peak current and power stage derating margin |
| Switching Frequency | Programmable 100 kHz–2.2 MHz via RT resistor - allows layout-optimized EMI mitigation and fast transient response |
| Feedback Reference | 1.0 V ±1% - ensures precise output regulation across –40°C to +125°C junction temperature range |
| Shutdown Quiescent Current | ≤2.6 µA - minimizes battery drain in always-on or low-power wake-up systems |
| Internal MOSFET RDS(on) | 133 mΩ @ VBIAS = 12 V - reduces conduction loss and thermal stress in high-duty-cycle applications |
Pinout & Package
LM51581RTER is housed in a 16-pin WQFN package (3.0 mm × 3.0 mm) with exposed thermal pad (EP), optimized for high-power density and thermal performance. The package uses leadless construction to reduce parasitic inductance and improve EMI behavior.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 16 PGND | Power ground return | Source connection of internal MOSFET; must be tied directly to large copper pour for low-impedance return path |
| 2 VCC | VCC regulator output | Supplies internal logic and gate driver; requires 1-µF ceramic bypass to PGND |
| 3 BIAS | High-voltage supply input | Feeds internal VCC regulator; accepts 3.2–60 V; enables operation below 1.5 V input when externally powered |
| 4 PGOOD | Open-drain power-good indicator | Signals valid output regulation (FB > 90% VREF); requires external pullup to system rail |
| 5 RT | Frequency programming input | Resistor-to-AGND sets fSW; 9.09 kΩ yields 2.2 MHz - critical for EMI compliance and magnetics selection |
| 6 EN/UVLO/SYNC | Multi-function control pin | Enables device, programs UVLO threshold via divider, or accepts external sync clock pulses - not left floating |
| 7 AGND | Analog ground reference | Separate ground for FB, COMP, SS; must connect via short, wide trace to minimize noise coupling |
| 8 COMP | Error amplifier output | Drives loop compensation network; sourcing/sinking capability defined by transconductance (2 mA/V) |
| 9 FB | Inverting error amplifier input | Sets output voltage via resistive divider; referenced to 1.0 V ±1% internal bandgap |
| 10 SS | Soft-start ramp control | External capacitor sets output voltage ramp rate; internal 10-µA current source ensures controlled start-up |
| 11 MODE | Hiccup/spread-spectrum enable | Voltage-selectable: 0 V (disabled), 370 mV (hiccup + spread), 620 mV (hiccup only), >1 V (spread only) |
| 13, 14 SW | Switch node | Drain of internal 85-V MOSFET; connects to inductor/transformer; high dv/dt node requiring tight layout |
| 12, 15 NC | No-connect terminals | Internally unconnected; must remain unpopulated and unconnected on PCB |
| EP | Exposed thermal pad | Must be soldered to AGND plane for thermal dissipation and EMI shielding; not electrically active |
Key Features
| Feature | Design Value |
|---|---|
| Dual random spread spectrum | Selectable via MODE pin; spreads switching energy across ±7.8% bandwidth to lower peak EMI emissions |
| Primary-side regulation (flyback) | Integrated transconductance error amplifier (Gm = 2 mA/V) and COMP pin eliminate optocoupler and secondary-side feedback |
| Programmable hiccup-mode OLP | 64-cycle fault detection + 8-cycle reset timer prevents thermal runaway during sustained overload |
| Accurate current limit | 1.63 A (typ) with <±5% variation over input voltage - avoids overdesigning inductor while ensuring reliability |
| Low-IQ operation | 670 µA operating current and ≤2.6 µA shutdown current extend battery life in portable and remote systems |
| External clock synchronization | EN/UVLO/SYNC pin accepts negative-edge sync pulses (100–2200 kHz) to align switching with system clocks or other converters |
Applications
| Battery-Powered Industrial PLC | LED Bias Supply |
|---|---|
|
Use Scenario: Powering 24-V I/O modules and communication interfaces from 9–36-V battery packs with transient immunity up to 65 V. IC Role / Device Role / Timing Role: Non-synchronous boost controller regulating stable 24-V rail; handles cold-cranking dips down to 1.5 V using BIAS pin. Use Value: Eliminates need for external high-voltage MOSFET and gate driver; 2.2-MHz operation enables <3-mm inductors and compact board area. |
Use Scenario: Driving high-brightness white LEDs in emergency lighting or signage where input varies from 12–48 V. IC Role / Device Role / Timing Role: Constant-voltage boost converter with PGOOD monitoring; soft-start prevents LED inrush stress. Use Value: ±1% VREF ensures consistent LED brightness; 133-mΩ RDS(on) maintains >92% efficiency at 1-A load. |
| Loop-Powered Fire Detection | Piezo Driver Bias Supply |
|
Use Scenario: Providing regulated 20-V bias to analog sensor front-ends and smoke chamber heaters in 4–20-mA loop-powered detectors. IC Role / Device Role / Timing Role: SEPIC converter accepting 12–24 V loop supply while delivering isolated, ripple-free 20-V output. Use Value: Dual random spread spectrum meets CISPR-11 Class B conducted EMI limits without added filtering components. |
Use Scenario: Generating 60–80-V bias for piezoelectric actuators in precision positioning systems powered from 12-V DC rails. IC Role / Device Role / Timing Role: Flyback controller with primary-side regulation; BIAS supplied from auxiliary winding for efficiency. Use Value: Integrated 85-V switch eliminates external HV FET; hiccup-mode OLP protects against piezo short-circuit faults. |
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 |
|---|---|---|---|
| LM5158RTER | Higher 3.26-A current limit, same 85-V rating and 2.2-MHz capability; shares identical pinout and package | Preferred for higher-power boost designs (>15 W) or lower-input-impedance flyback topologies | Select LM5158RTER when peak switch current exceeds 1.63 A; no PCB changes required due to pin-to-pin compatibility |
| TPS40210DRCT | Fixed 1-MHz frequency, no spread spectrum, 40-V max input, external MOSFET required; 10-pin WSON | Suitable for cost-sensitive, lower-voltage (<36 V) boost applications where EMI is less critical | Choose TPS40210DRCT only if input stays below 40 V and design can accommodate external FET and larger solution size |
Compared with LM51581RTER, LM5158RTER offers double the current capability in identical footprint for scalable power stages, while TPS40210DRCT trades integration and voltage range for lower unit cost in constrained-voltage applications - neither matches the 60-V input / 83-V output / spread-spectrum combination of LM51581RTER.
Availability
LM51581RTER is available at Aetrix Electronics and suitable for battery-powered industrial PLCs, LED bias supplies, loop-powered fire detection systems, and piezo driver bias supplies requiring stable component supply, long-term lifecycle support, and guaranteed authentic sourcing.
Supply support for LM51581RTER 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 LM5158x family was designed specifically for wide-input, high-voltage DC-DC conversion in harsh environments - targeting battery-powered industrial, automotive, and safety-critical systems needing robust transient immunity and minimal external components.
FAQ
What is the minimum input voltage for LM51581RTER startup?
The LM51581RTER starts up from a minimum 3.2-V input supply. However, if the BIAS pin is supplied with ≥3.2 V from an auxiliary source (e.g., output rail or external supply), the device operates with input as low as 1.5 V - enabling reliable cold-cranking performance in battery systems. This behavior is confirmed in Section 3 and Figure 9-5 of the SNVSBZ7 datasheet.
Does LM51581RTER support flyback topology with primary-side regulation?
Yes, LM51581RTER supports primary-side regulated flyback without optocoupler, enabled by its integrated transconductance error amplifier and COMP pin. The FB pin senses reflected output voltage, and the internal 1.0-V reference ensures ±1% regulation accuracy. This capability is explicitly documented in the "Description" and "Feature Description" sections of the official datasheet.
How is switching frequency programmed on LM51581RTER?
Switching frequency on LM51581RTER is set by a single resistor between the RT pin and AGND. A 9.09-kΩ resistor yields 2.2 MHz (typ), 49.3 kΩ yields ~440 kHz, and 220 kΩ yields ~100 kHz - all values verified in Table 8-5 and Figure 8-10 of the SNVSBZ7 datasheet. Frequency remains stable across temperature and input voltage.
What protection features does LM51581RTER include?
LM51581RTER integrates constant-current limiting, programmable line UVLO, overvoltage protection (OVP), thermal shutdown at 175°C (15°C hysteresis), and selectable hiccup-mode overload protection. All protections are hardware-based and operate independently of external components - details are specified in Sections 1, 9.3, and Table 8-5 of the production datasheet.
Can LM51581RTER synchronize to an external clock?
Yes, LM51581RTER supports external clock synchronization via the EN/UVLO/SYNC pin. Applying negative-edge pulses (100–2200 kHz) to this pin locks the internal oscillator to the external signal - useful for noise-sensitive systems or multi-converter phase alignment. This function is fully documented in Section 9.3.1 and Table 7-1 of the SNVSBZ7 datasheet.
LM51581RTER 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):
- 60V
- Voltage - Output (Min/Fixed):
- 1.5V
- Voltage - Output (Max):
- 83V
- Current - Output:
- 1.63A (Switch)
- 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)
LM51581RTER FAQ
1.How can I place an order for LM51581RTER through Aetrix?
Please submit a Request for Quotation (RFQ) for LM51581RTER 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 LM51581RTER reliable?
The price and inventory of LM51581RTER are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM51581RTER is usually 5 days.
3.What payment methods are accepted for LM51581RTER?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM51581RTER transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM51581RTER?
LM51581RTER orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM51581RTER 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 LM51581RTER?
For technical support, including LM51581RTER datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM51581RTER requirements.
6.How does Aetrix verify that LM51581RTER is sourced from the original manufacturer or authorized distributors?
All LM51581RTER 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 LM51581RTER meets industry standards.
7.What is the process for return or replacement of LM51581RTER?
All LM51581RTER units undergo pre-shipment inspection (PSI). If there is an issue with LM51581RTER, 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 LM51581RTER part is unused and in its original packaging.
Return procedure for LM51581RTER:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM51581RTER Tags
-
TPS562201DDCR
Texas Instruments
-
MC34063ABD-TR
STMicroelectronics
-
TPS561201DDCR
Texas Instruments
-
MC33063ADR
Texas Instruments
-
MC34063ADR
Texas Instruments
-
TPS560200DBVR
Texas Instruments
-
AP3012KTR-G1
Diodes Incorporated
-
TLV61048DBVR
Texas Instruments
-
AZ34063UMTR-G1
Diodes Incorporated
-
TPS562200DDCR
Texas Instruments
-
AP62300TWU-7
Diodes Incorporated
-
MC34063EBD-TR
STMicroelectronics
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
