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Texas Instruments LM2738XMYX/NOPB
- Part No.:
- LM2738XMYX/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 8-PowerTSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
LM2738XMYX/NOPB.pdf
- Description:
- IC REG BUCK ADJ 1.5A 8HVSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,721
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Product details
Overview
LM2738XMYX/NOPB from Texas Instruments is a monolithic 1.6-MHz, 1.5-A synchronous step-down DC-DC switching regulator in an 8-pin WSON (3.0 mm × 3.0 mm) package with PowerPAD™ thermal enhancement. It integrates a 250-mΩ NMOS switch, internal soft-start, current-mode PWM control, and 0.8-V ±2% reference for precise output regulation from 0.8 V to 18 V. Used in space-constrained USB-powered devices and set-top boxes requiring high power density.
For engineers reviewing the LM2738XMYX/NOPB datasheet, LM2738XMYX/NOPB pinout, LM2738XMYX/NOPB application, or LM2738XMYX/NOPB equivalent, key selection criteria include verified 1.6-MHz fixed-frequency operation, 400-nA shutdown current, thermal shutdown at 165°C, cycle-by-cycle current limit (2.9 A typ), and BOOST/SW bootstrap gate-drive architecture supporting efficient high-side NMOS switching.
Technical Context
The LM2738XMYX/NOPB implements constant-frequency current-mode PWM control with internal compensation, enabling stable regulation across wide input (3–20 V) and output (0.8–18 V) ranges without external loop components. Its 1.6-MHz oscillator frequency enables use of sub-3-mm surface-mount inductors and ceramic capacitors while maintaining >90% efficiency at 1.5-A load.
Bootstrap-based gate drive (BOOST–SW ≥ 2.5 V, ≤ 5.5 V) powers the integrated 250-mΩ NMOS switch; undervoltage lockout (2.7 V rising, 2.3 V falling) and output overvoltage protection (16% above 0.8 V reference) provide robust system-level fault coverage. Soft-start ramps the 0.8-V reference over ~600 µs to limit in-rush current.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switching Frequency | 1.6 MHz (fixed, LM2738X variant); enables compact 2.2-µH inductors and low-ESR ceramic output caps. |
| Output Current | 1.5 A continuous; supports core power in HDDs and local point-of-load regulation. |
| Input Voltage Range | 3 V to 20 V; accommodates 5-V/12-V rails and battery-backed systems. |
| Output Voltage Range | 0.8 V to 18 V; set via external resistor divider on FB pin with 0.8-V ±2% internal reference. |
| Shutdown Current | 400 nA; minimizes battery drain in always-on USB or portable applications. |
| Switch RDS(ON) | 250 mΩ (typ); reduces conduction loss and improves thermal performance at full load. |
| Current Limit | 2.9 A (typ), cycle-by-cycle; protects internal switch during overload or short-circuit events. |
Pinout & Package
LM2738XMYX/NOPB uses an 8-pin WSON package (3.0 mm × 3.0 mm) with exposed thermal pad (DAP) connected to GND for enhanced heat dissipation. Pin numbering follows standard top-view orientation with pin 1 marked by dot or bevel.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - BOOST | Bootstrap supply input | Drives NMOS gate; requires 0.1-µF X7R capacitor to SW; must maintain 2.5–5.5 V above SW. |
| 2 - VIN | Main power input | Supplies power stage; connect 10-µF X5R bypass cap close to pin; tied internally to VCC. |
| 3 - VCC | Internal regulator input | Internally tied to VIN; no separate connection required. |
| 4 - EN | Enable control | Logic-high (>1.4 V) enables operation; logic-low (<0.4 V) enters 400-nA shutdown mode. |
| 5,7 - GND | Signal & power ground | Low-impedance return path; feedback resistors must tie to these pins for accuracy. |
| 6 - FB | Voltage feedback input | Senses output via resistor divider; regulates to 0.8 V ±2%; supports OVP at 0.93 V. |
| 8 - SW | Switch node output | Connects to inductor and catch diode; swings from GND to VIN minus RDS(ON)×ILOAD. |
| DAP | Thermal pad | Must be soldered to PCB GND plane for thermal management; critical for 125°C junction operation. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 1.6-MHz switching | Enables use of <3-mm inductors and chip capacitors; reduces solution footprint vs lower-frequency alternatives. |
| Integrated 250-mΩ NMOS switch | Eliminates external high-side FET; achieves >90% efficiency at 1.5-A load with minimal BOM count. |
| Internal soft-start (600 µs) | Prevents in-rush current surges during power-up; avoids input rail droop in battery- or USB-fed systems. |
| Output overvoltage protection | Shuts down SW when FB exceeds 0.93 V (16% above 0.8-V reference); safeguards downstream ICs. |
| Thermal shutdown (165°C) | Disables switching until junction cools to ~150°C; prevents permanent damage under sustained overload. |
Applications
| Local Point-of-Load Regulation | USB-Powered Devices |
|---|---|
Use Scenario: Regulating 12-V or 5-V bus to 1.5-V/1.5-A for FPGA I/O banks or microcontroller cores on dense PCBs. IC Role / Device Role / Timing Role: Primary buck converter delivering tightly regulated, low-noise DC power with fast transient response. Use Value: 1.6-MHz operation allows 2.2-µH inductor and 22-µF ceramic output cap-reducing board area by >40% vs 550-kHz solutions. | Use Scenario: Powering portable media players or USB hubs from 5-V USB Type-A ports with strict in-rush limits. IC Role / Device Role / Timing Role: Main DC-DC regulator managing enable sequencing and low-quiescent shutdown. Use Value: 400-nA shutdown current extends battery life; internal soft-start meets USB 2.0 in-rush requirements (<100 mA). |
| Set-Top Boxes | Core Power in HDDs |
Use Scenario: Generating 3.3-V/1.5-A for SoC subsystems in consumer STBs where EMI and thermal density are critical. IC Role / Device Role / Timing Role: High-efficiency buck regulator operating from 12-V intermediate rail with tight output tolerance. Use Value: 90%+ efficiency at full load reduces heatsink requirements; WSON package simplifies thermal layout. | Use Scenario: Supplying 5-V/1.5-A to HDD motor controller ICs and interface logic in slim-profile storage enclosures. IC Role / Device Role / Timing Role: Compact, thermally robust step-down regulator handling dynamic load steps up to 1.5 A. Use Value: Cycle-by-cycle current limit (2.9 A typ) and thermal shutdown protect against motor stall faults. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2738YMYX/NOPB | 550-kHz switching frequency; higher max duty cycle (95% vs 92%); lower boost current (2.5 mA vs 4.5 mA). | Better suited for high-input-to-output voltage ratios (e.g., 12 V → 5 V) where lower frequency improves efficiency. | Select LM2738YMYX/NOPB when board space permits larger inductors and lower EMI is prioritized over miniaturization. |
| TPS62231DRVR | 3-MHz fixed frequency; 0.6-V reference; 2-A output; integrated sync rectifier; smaller 2-mm × 2-mm WSON. | Higher switching frequency enables even smaller passives but requires tighter layout for EMI control. | Choose TPS62231DRVR for next-gen designs needing >2-A output or deeper VIN-to-VOUT conversion with ultra-compact footprint. |
Compared with LM2738YMYX/NOPB, the LM2738XMYX/NOPB trades marginally lower light-load efficiency for significantly reduced passive size; versus TPS62231DRVR, it offers proven thermal robustness and simpler bootstrap implementation at the cost of peak current and integration level.
Availability
LM2738XMYX/NOPB is available at Aetrix Electronics and suitable for USB-powered devices, set-top boxes, and local point-of-load regulation requiring stable component supply, long-term manufacturability, and TI-qualified automotive-grade traceability.
Supply support for LM2738XMYX/NOPB 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 designing analog ICs, embedded processors, and digital signal solutions for industrial, automotive, and consumer markets.
The LM2738XMYX/NOPB belongs to TI's high-frequency DC-DC converter product line, engineered for space-constrained applications demanding high power density, low quiescent current, and robust fault protection without external compensation.
FAQ
What is the exact switching frequency of LM2738XMYX/NOPB and how is it set?
The LM2738XMYX/NOPB has a factory-trimmed fixed switching frequency of 1.6 MHz, specific to the 'X' suffix variant. This frequency is internally generated by a precision oscillator and cannot be adjusted externally. It enables use of small 2.2-µH inductors and low-ESR ceramic capacitors while maintaining stable current-mode PWM regulation across the full 3–20-V input range. The LM2738XMYX/NOPB datasheet specifies typical frequency as 1.6 MHz with ±20% variation over temperature and process.
Does LM2738XMYX/NOPB require an external bootstrap capacitor, and what value is recommended?
Yes, LM2738XMYX/NOPB requires a 0.1-µF X7R ceramic capacitor (e.g., TDK C1005X7R1C104K) between BOOST and SW pins to sustain gate drive for the internal NMOS switch. This capacitor must be placed as close as possible to the pins with short, low-inductance traces. The LM2738XMYX/NOPB datasheet confirms this value supports reliable 1.6-MHz operation and maintains BOOST–SW voltage within the required 2.5–5.5-V window across all loads and temperatures.
How does the enable (EN) pin function on LM2738XMYX/NOPB, and what are its voltage thresholds?
The EN pin on LM2738XMYX/NOPB controls device startup and shutdown. A logic-high voltage ≥1.4 V (rising threshold) enables regulation; a logic-low voltage ≤0.4 V (falling threshold) places LM2738XMYX/NOPB into shutdown mode with 400-nA quiescent current. The pin must never exceed VIN + 0.3 V. Internal hysteresis prevents chatter near the threshold, and the pin must not float-TI recommends pulling to GND or VIN via a resistor if unused. This behavior is explicitly characterized in the LM2738XMYX/NOPB Electrical Characteristics table.
What thermal management provisions does LM2738XMYX/NOPB include, and how is the exposed pad used?
LM2738XMYX/NOPB incorporates thermal shutdown at 165°C and features an exposed thermal pad (DAP) that must be soldered to a PCB GND plane for effective heat transfer. The DAP provides the lowest thermal resistance path (RθJB = 13.2°C/W) to the board. TI's LM2738XMYX/NOPB datasheet specifies minimum solder mask opening, thermal via count (≥4), and copper area guidelines to achieve rated 125°C junction temperature under 1.5-A load. Failure to connect the DAP compromises thermal performance and may trigger premature shutdown.
Can LM2738XMYX/NOPB regulate output voltages below 1 V, and what limits its minimum setting?
Yes, LM2738XMYX/NOPB can regulate down to 0.8 V, as defined by its internal 0.8-V ±2% voltage reference. The minimum output is constrained by this reference-not by duty cycle or stability-and is confirmed in both the Features and Recommended Operating Conditions sections of the LM2738XMYX/NOPB datasheet. To achieve 0.8 V, the feedback divider must satisfy VFB = VOUT × [R2/(R1+R2)] = 0.8 V. Lower outputs are not supported; attempting sub-0.8-V regulation results in loss of regulation and potential instability.
LM2738XMYX/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-PowerTSSOP, 8-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3V
- Voltage - Input (Max):
- 20V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 18V
- Current - Output:
- 1.5A
- Frequency - Switching:
- 1.6MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-HVSSOP
LM2738XMYX/NOPB FAQ
1.How can I place an order for LM2738XMYX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2738XMYX/NOPB 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 LM2738XMYX/NOPB reliable?
The price and inventory of LM2738XMYX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2738XMYX/NOPB is usually 5 days.
3.What payment methods are accepted for LM2738XMYX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2738XMYX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2738XMYX/NOPB?
LM2738XMYX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2738XMYX/NOPB 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 LM2738XMYX/NOPB?
For technical support, including LM2738XMYX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2738XMYX/NOPB requirements.
6.How does Aetrix verify that LM2738XMYX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2738XMYX/NOPB 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 LM2738XMYX/NOPB meets industry standards.
7.What is the process for return or replacement of LM2738XMYX/NOPB?
All LM2738XMYX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2738XMYX/NOPB, 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 LM2738XMYX/NOPB part is unused and in its original packaging.
Return procedure for LM2738XMYX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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