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Semtech Corporation LR1121IMLTRT
- Part No.:
- LR1121IMLTRT
- Manufacturer:
- Semtech Corporation
- Category:
- RF Transceiver ICs
- Package:
- 32-VFQFN Exposed Pad
- Datasheet:
-
LR1121IMLTRT.pdf
- Description:
- IC RF TXRX ISM>1GHZ 32QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,000
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Product details
Overview
LR1121IMLTRT from Semtech is a Transient Diverting Suppressor (TDS) designed for high-energy EOS protection of 22V-rated power or I/O lines. It delivers ±30kV IEC 61000-4-2 ESD immunity, 40A peak pulse current (8/20μs), and a stable 27.5–28V clamping voltage across temperature and current range. It protects USB Type-C power delivery buses and load switch inputs in industrial and IoT equipment.
For engineers reviewing the LR1121IMLTRT datasheet, pinout, applications, or equivalent options, key selection criteria include clamping voltage stability under surge, low dynamic resistance (20 mΩ), junction capacitance (175 pF at 22V), and DFN 1.6×1.6mm package compatibility with high-density PCB layouts.
Technical Context
The LR1121IMLTRT uses a surge-rated FET as its primary protection element, activated by a precision trigger circuit that turns on the shunt path when transient voltage exceeds breakdown. Unlike conventional TVS diodes, its clamping voltage remains nearly constant-27.5–28V-from 24A to 40A peak pulse current due to decreasing RDS(on) under surge.
It operates across –40°C to +125°C, maintains <600 nA reverse leakage at 22V, and exhibits stable 175 pF capacitance at 1 MHz and 22V bias. Its functional architecture enables robust protection for unsymmetrical lines per IEC 61000-4-5 (±1kV, 1.2/50μs + 8/20μs combo wave, RS = 42Ω).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Working Voltage | 22 V - matches nominal USB PD bus voltage and avoids false triggering during normal operation. |
| Clamping Voltage | 27.5–28 V at 40A (8/20μs) - stays below typical 30V damage threshold of USB PD controllers and load switches. |
| Peak Pulse Current | 40 A (8/20μs) - meets IEC 61000-4-5 Level 4 surge immunity for industrial equipment interfaces. |
| ESD Withstand | ±30 kV contact & air (IEC 61000-4-2) - exceeds automotive and industrial ESD requirements without external shielding. |
| Dynamic Resistance | 20 mΩ - ensures minimal voltage rise under high di/dt transients, critical for fast-rising lightning surges. |
| Junction Capacitance | 175 pF at 22V, 1 MHz - low enough for 22V power rail protection without signal integrity impact on DC/low-frequency lines. |
| Package | DFN 1.6 mm × 1.6 mm × 0.55 mm, 6-lead - enables compact placement near connectors with minimal board area and thermal mass. |
Pinout & Package
LR1121IMLTRT is housed in a Pb-free, RoHS-compliant DFN 1.6 mm × 1.6 mm × 0.55 mm package with exposed thermal pad not required (energy dissipated in silicon). All six pins are electrically active: three GND and three IN terminals must be connected in parallel for full 40A rating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pins 1, 2, 3 | GND | Common ground return path for surge current; all three must be tied to low-inductance ground plane via multiple vias. |
| Pins 4, 5, 6 | IN | Input connection to protected line (e.g., VBUS in USB-C); parallel routing ensures uniform current sharing and minimizes parasitic inductance. |
Key Features
| Feature | Design Value |
|---|---|
| FET-based transient shunting | Replaces conventional TVS with active clamping-enables flat VC vs. IPP curve and eliminates temperature-induced clamping drift. |
| Stable clamping over temperature | 27.5–28 V clamping maintained from –40°C to +125°C-ensures consistent protection in harsh industrial environments. |
| Low dynamic resistance | 20 mΩ measured between 1A–40A (8/20μs)-reduces overshoot during fast-rising transients like ESD and lightning. |
| High EFT immunity | ±4 kV per IEC 61000-4-4 (5/50 ns, 5 kHz & 100 kHz bursts)-protects against repetitive switching noise in motor drives and PLCs. |
| UL 94V-0 molding compound | Ensures flame-retardant reliability in enclosed industrial enclosures and safety-critical power systems. |
Applications
| USB Type-C Power Delivery Protection | Industrial Load Switch Input Protection |
|---|---|
|
Use Scenario: Protecting 20–22V VBUS lines in USB-C ports supporting up to 100W PD, exposed to ESD and hot-plug surges. IC Role / Device Role / Timing Role: Transient diverting suppressor placed directly at connector, clamping surges before they reach PD controller or e-fuse IC. Use Value: Maintains 27.5–28V clamping across temperature-prevents false trips and guarantees safe operation below 30V PD controller absolute maximum ratings. |
Use Scenario: Securing input rails of industrial-grade load switches (e.g., HS2950P) used in remote meters, robotics, and factory automation. IC Role / Device Role / Timing Role: Primary front-end surge protector absorbing 40A transients while limiting voltage stress on internal FET gate oxide. Use Value: Prevents catastrophic failure of load switch ICs during lightning-induced surges on long cable runs or ungrounded installations. |
| IoT Edge Node Power Bus Protection | Storage Device 22V Rail Protection |
|
Use Scenario: Safeguarding 22V auxiliary power rails in battery-backed IoT gateways and edge AI nodes deployed outdoors or in utility infrastructure. IC Role / Device Role / Timing Role: Standalone EOS protector on main DC input, coordinated with upstream fuse and downstream LDOs. Use Value: Delivers ±30kV ESD and 40A surge handling in 1.6×1.6mm footprint-enables ruggedized, space-constrained designs without derating. |
Use Scenario: Protecting 22V power supplies feeding NVMe SSD modules or enterprise HDD backplanes subject to hot-swap and system-level surges. IC Role / Device Role / Timing Role: High-energy clamping device placed at board edge before bulk capacitance and PMIC input. Use Value: Limits transient overvoltage to ≤28V during 1.2/50μs + 8/20μs combo-wave events-preserves data integrity and prevents storage controller latch-up. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TDS2211P.C | Same die, identical electrical specs, same DFN 1.6×1.6mm package; differs only in tape-and-reel packaging (3,000 pcs/reel vs. LR1121IMLTRT's unspecified reel quantity). | Functionally interchangeable in all PCB layouts and protection circuits; no design change required. | Select TDS2211P.C for volume procurement where standard Semtech reel size is preferred. |
| SP1003-02HTG | TVS diode array (2-line), 24V working voltage, 30A (8/20μs), 35V clamping-higher VC, fixed RDYN, and temperature-sensitive clamping. | Limited to lower-energy threats; less suitable for sustained 40A surges or high-temperature industrial use. | Consider SP1003-02HTG only if cost sensitivity outweighs clamping stability and surge margin requirements. |
Compared with TDS2211P.C, LR1121IMLTRT offers identical protection performance but may differ in reel logistics; versus SP1003-02HTG, LR1121IMLTRT provides superior clamping consistency, higher surge rating, and broader temperature resilience-critical for mission-critical 22V rail protection.
Availability
LR1121IMLTRT is available at Aetrix Electronics and suitable for USB Type-C power delivery systems, industrial load switch inputs, and IoT edge node power buses requiring stable component supply and guaranteed EOS protection performance.
Supply support for LR1121IMLTRT 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
Semtech Corporation is a U.S.-based fabless semiconductor company specializing in high-performance analog and mixed-signal semiconductors for power management, protection, and sensing applications.
The LR1121IMLTRT belongs to Semtech's Transient Diverting Suppressor (TDS) family, engineered to replace traditional TVS diodes with active FET-based clamping for stable, temperature-invariant surge protection in demanding industrial and high-reliability interfaces.
FAQ
What is the primary protection function of the LR1121IMLTRT?
The LR1121IMLTRT functions as a transient diverting suppressor that actively shunts high-energy electrical overstress (EOS) events-including ESD, lightning surges, and EFT-to ground using an integrated surge-rated FET. Unlike passive TVS diodes, LR1121IMLTRT maintains a stable ~27.5–28V clamping voltage across its full 40A surge rating and operating temperature range, making it ideal for protecting sensitive 22V power rails.
Does the LR1121IMLTRT require a thermal pad on the PCB?
No, the LR1121IMLTRT does not require a thermal pad. Its DFN package dissipates surge energy within the silicon die rather than relying on conduction through an exposed pad. The datasheet explicitly states "no thermal pad is needed," and layout guidelines emphasize low-inductance grounding via multiple vias to pins 1–3 instead of thermal copper pours.
Can the LR1121IMLTRT be used on bidirectional signal lines like USB DP/DM?
No, the LR1121IMLTRT is designed exclusively for unidirectional 22V power or I/O line protection-not high-speed bidirectional data lines. Its 175 pF capacitance would severely degrade signal integrity on SuperSpeed USB or PCIe lanes. For DP/DM lines, Semtech recommends low-capacitance TVS devices such as RClamp3371ZC (<0.25 pF), while LR1121IMLTRT is reserved for VBUS and other DC power paths.
How does the LR1121IMLTRT compare to standard TVS diodes in clamping behavior?
The LR1121IMLTRT clamps at a nearly constant 27.5–28V from 24A to 40A and across –40°C to +125°C, whereas standard TVS diodes exhibit linearly increasing clamping voltage (VC = VBR + IPP × RDYN) and significant temperature drift. This makes LR1121IMLTRT more reliable for protecting voltage-sensitive components like USB PD controllers, where exceeding 30V risks permanent damage.
What is the recommended PCB layout for optimal performance of the LR1121IMLTRT?
Place the LR1121IMLTRT as close as possible to the protected connector (e.g., USB-C receptacle). Route pins 4–6 (IN) together in a single short, wide trace to the protected line, and connect pins 1–3 (GND) directly to a solid ground plane using ≥3 vias. Avoid stubs or splits-parallel pin connections minimize inductance and ensure balanced current sharing during 40A surges.
LR1121IMLTRT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Semtech Corporation
- Series:
- LoRa™
- Package/Case:
- 32-VFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Programmable:
- -
- Type:
- TxRx Only
- RF Family/Standard:
- General ISM > 1GHz
- Protocol:
- LoRa™
- Modulation:
- 2-FSK, FHSS, FSK, GFSK
- Frequency:
- 150MHz ~ 2.5GHz
- Data Rate (Max):
- 250kbps
- Power - Output:
- 22dBm
- Sensitivity:
- -144dBm
- Memory Size:
- 8kB RAM
- Serial Interfaces:
- SPI
- GPIO:
- -
- Voltage - Supply:
- 1.8V ~ 3.7V
- Current - Receiving:
- 5.4mA ~ 8.3mA
- Current - Transmitting:
- 18.5mA ~ 118mA
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 32-QFN (5x5)
LR1121IMLTRT FAQ
1.How can I place an order for LR1121IMLTRT through Aetrix?
Please submit a Request for Quotation (RFQ) for LR1121IMLTRT 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 LR1121IMLTRT reliable?
The price and inventory of LR1121IMLTRT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LR1121IMLTRT is usually 5 days.
3.What payment methods are accepted for LR1121IMLTRT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LR1121IMLTRT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LR1121IMLTRT?
LR1121IMLTRT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LR1121IMLTRT 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 LR1121IMLTRT?
For technical support, including LR1121IMLTRT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LR1121IMLTRT requirements.
6.How does Aetrix verify that LR1121IMLTRT is sourced from the original manufacturer or authorized distributors?
All LR1121IMLTRT 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 LR1121IMLTRT meets industry standards.
7.What is the process for return or replacement of LR1121IMLTRT?
All LR1121IMLTRT units undergo pre-shipment inspection (PSI). If there is an issue with LR1121IMLTRT, 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 LR1121IMLTRT part is unused and in its original packaging.
Return procedure for LR1121IMLTRT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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