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Texas Instruments LM2738YSDX/NOPB
- Part No.:
- LM2738YSDX/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 8-WFDFN Exposed Pad
- Datasheet:
-
LM2738YSDX/NOPB.pdf
- Description:
- IC REG BUCK ADJ 1.5A 8WSON
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
LM2738YSDX/NOPB from Texas Instruments is a monolithic 550-kHz, 1.5-A synchronous step-down DC-DC switching regulator in an 8-pin WSON package. It integrates a 250-mΩ NMOS power switch, internal soft-start, current-mode PWM control, and 0.8-V ±2% reference. Designed for space-constrained point-of-load regulation in USB-powered devices and set-top boxes.
For engineers reviewing the LM2738YSDX/NOPB datasheet, LM2738YSDX/NOPB pinout, LM2738YSDX/NOPB application, or LM2738YSDX/NOPB equivalent, key selection criteria include input voltage range (3–20 V), output voltage adjustability (0.8–18 V), shutdown current (400 nA), thermal shutdown (165°C), and boost-capacitor–dependent gate-drive architecture.
Technical Context
The LM2738YSDX/NOPB implements fixed-frequency current-mode PWM control with internal compensation, enabling stable regulation across wide load and line variations without external loop components. Its 550-kHz switching frequency (confirmed for Y-suffix variants) supports compact 2.2-µH inductors and ceramic output capacitors while maintaining >90% efficiency at 12-VIN/3.3-VOUT/1.5-A.
Operation relies on bootstrap gate drive: the BOOST pin supplies gate voltage to the internal NMOS switch via an external capacitor, requiring VBOOST–VSW between 2.5 V and 5.5 V. Undervoltage lockout (2.7 V rising, 2.3 V falling) and cycle-by-cycle current limit (2.9 A typical) enforce safe startup and overload protection.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switching Frequency | 550 kHz - Enables use of small surface-mount inductors (e.g., 2.2 µH) and low-ESR ceramic capacitors without sacrificing transient response. |
| Max Output Current | 1.5 A - Sustained load capability with integrated 250-mΩ NMOS switch; peak switch current limit is 2.9 A (typical). |
| Input Voltage Range | 3 V to 20 V - Supports wide-input applications including 5-V/12-V rails and battery-backed systems. |
| Output Voltage Range | 0.8 V to 18 V - Adjustable via external resistor divider; 0.8-V ±2% internal reference ensures tight regulation accuracy. |
| Shutdown Current | 400 nA - Ultra-low quiescent draw during EN = low, critical for battery life in portable USB-powered devices. |
| Thermal Shutdown | 165°C - Protects against sustained overloads; device resumes operation after junction cools to ~150°C. |
| Feedback Reference | 0.8 V - Precision internal bandgap reference used directly by FB pin; enables accurate output setting independent of temperature drift. |
Pinout & Package
LM2738YSDX/NOPB uses an 8-pin WSON (NGQ) package, 3.00 mm × 3.00 mm, with exposed thermal pad (DAP) connected to GND for enhanced thermal dissipation. Package thermal resistance RθJA = 45.9°C/W under JEDEC-standard 4-layer PCB conditions.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - BOOST | Bootstrap supply input | Drives NMOS gate; requires external 0.1-µF ceramic capacitor to SW; must maintain 2.5–5.5 V above SW for full switch enhancement. |
| 2,3 - VIN / VCC | Power input & bias supply | Tied together at package; supplies power stage and internal regulator; bypass with ≥10-µF ceramic capacitor near pins. |
| 4 - EN | Enable control | Logic-high (>1.4 V) enables regulation; logic-low (<0.4 V) disables with 400-nA shutdown current; must not exceed VIN + 0.3 V. |
| 5,7 - GND | Signal & power ground | Common return for feedback network, power path, and thermal pad; place bottom feedback resistor adjacent to these pins. |
| 6 - FB | Voltage feedback input | Connects to resistor divider (R1/R2) to set output; senses 0.8-V reference; input bias current <100 nA enables high-impedance dividers. |
| 8 - SW | Switch node output | Drives external inductor and catch diode; swings from ~VIN (on) to ~–0.3 V (off); high dv/dt requires careful layout and ground plane integrity. |
Key Features
| Feature | Design Value |
|---|---|
| Internal soft-start | Ramps reference from 0 V to 0.8 V over ~600 µs, limiting in-rush current during startup and preventing output overshoot. |
| Output overvoltage protection | Disables switch when FB exceeds 0.93 V (16% above 0.8-V reference), protecting downstream loads from fault-induced overvoltage. |
| Current-mode PWM control | Provides inherent cycle-by-cycle current limiting, fast transient response, and simplified loop compensation without external components. |
| Thermal shutdown with hysteresis | Shuts down at 165°C junction; restarts at ~150°C, preventing thermal cycling and ensuring robust operation under sustained overload. |
| Undervoltage lockout (UVLO) | Enables only when VIN rises above 2.7 V (typical); 400-mV hysteresis prevents chatter during non-monotonic power-up ramps. |
Applications
| USB-Powered Devices | Set-Top Boxes |
|---|---|
Use Scenario: Powering FPGA I/O banks and USB PHY circuitry from a 5-V USB port with strict size and thermal constraints. IC Role / Device Role / Timing Role: Primary buck regulator delivering regulated 3.3 V or 1.8 V at up to 1.5 A from 5-V input; manages dynamic load steps during data transfer bursts. Use Value: 550-kHz operation allows 2.2-µH inductor and 22-µF ceramic output capacitor, reducing solution footprint by >40% vs lower-frequency alternatives. | Use Scenario: Generating core voltage for MPEG decoder SoCs and HDMI interface circuitry in consumer STB platforms. IC Role / Device Role / Timing Role: Local point-of-load regulator converting 12-V rail to 1.2-V or 1.5-V core supply; handles rapid load transients from video decode activity. Use Value: Internal current-mode control and 0.8-V reference deliver ±1% output accuracy across –40°C to +85°C ambient, meeting STB thermal reliability requirements. |
| Battery-Powered Devices | DSL Modems |
Use Scenario: Regulating 3.3-V logic supply from a 2-cell Li-ion battery (6–8.4 V) in portable test equipment with multi-day standby life. IC Role / Device Role / Timing Role: Main system regulator with enable-controlled sleep mode; enters 400-nA shutdown during idle periods. Use Value: Ultra-low shutdown current extends battery runtime; 3-V minimum input supports deep discharge operation down to 3.0 V per cell. | Use Scenario: Providing stable 5-V and 3.3-V supplies for ADSL2+ PHY and microcontroller subsystems in wall-powered DSL modems. IC Role / Device Role / Timing Role: Secondary buck converter deriving 3.3 V from 5-V intermediate rail; operates continuously with high line/load regulation. Use Value: 0.02%/V line regulation and <100-nA FB bias current ensure stable output despite upstream 5-V rail variation from AC adapter ripple. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2738XSDX/NOPB | 1.6-MHz switching frequency; higher switching losses but smaller passive components; 2.5% higher quiescent current in active mode. | Better suited for ultra-compact layouts where board area is more critical than efficiency at light loads. | Select LM2738XSDX/NOPB only if 1.6-MHz operation is required to meet EMI filtering or size targets; LM2738YSDX/NOPB offers superior light-load efficiency. |
| TPS62231DRVR | 3-MHz fixed-frequency, 600-mA output, integrated MOSFETs, 2.05-V min input; no external BOOST requirement. | Limited to lower-current applications; lacks adjustable UVLO and OVP; optimized for single-cell Li-ion systems. | Choose TPS62231DRVR only for sub-600-mA loads and 2.05–6-V input ranges; LM2738YSDX/NOPB remains preferred for 1.5-A, 3–20-V designs requiring robust protection features. |
Compared with LM2738XSDX/NOPB, LM2738YSDX/NOPB trades higher inductor size for better light-load efficiency and lower EMI emissions; versus TPS62231DRVR, it delivers 2.5× higher current, wider input range, and comprehensive fault protection-making it suitable for industrial and broadband infrastructure applications where reliability and flexibility are prioritized.
Availability
LM2738YSDX/NOPB is available at Aetrix Electronics and suitable for USB-powered devices, set-top boxes, and DSL modems requiring stable component supply with long-term production support and consistent parametric performance.
Supply support for LM2738YSDX/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 company headquartered in Dallas, Texas, delivering analog and embedded processing solutions across industrial, automotive, and personal electronics markets.
The LM2738YSDX/NOPB belongs to TI's high-frequency DC-DC buck regulator product line, engineered for compact, efficient local power conversion in space-constrained consumer and broadband equipment where thermal performance and protection robustness are critical.
FAQ
What is the switching frequency of the LM2738YSDX/NOPB?
The LM2738YSDX/NOPB operates at a fixed 550-kHz switching frequency, as confirmed by its Y-suffix designation and TI's SNVS556C datasheet. This frequency enables use of small 2.2-µH inductors and ceramic output capacitors while maintaining >90% efficiency at 12-VIN/3.3-VOUT/1.5-A. The X-suffix variant runs at 1.6 MHz.
Does the LM2738YSDX/NOPB require an external bootstrap capacitor?
Yes, the LM2738YSDX/NOPB requires an external 0.1-µF ceramic capacitor between BOOST and SW pins to generate sufficient gate-drive voltage for the internal NMOS switch. Per datasheet Section 7.3.1, VBOOST–VSW must be maintained between 2.5 V and 5.5 V; failure to populate CBOOST will prevent proper switch turn-on and cause regulation failure.
What protection features does the LM2738YSDX/NOPB include?
The LM2738YSDX/NOPB integrates thermal shutdown (165°C trip), cycle-by-cycle current limiting (2.9 A typical), undervoltage lockout (2.7 V rising threshold), and output overvoltage protection (FB > 0.93 V disables switch). These features are documented in Sections 7.3.3–7.3.6 of the SNVS556C datasheet and operate independently without external components.
Can the LM2738YSDX/NOPB regulate output voltages below 1 V?
No-the LM2738YSDX/NOPB's internal 0.8-V reference sets the practical lower limit for adjustable output. While the datasheet states "0.8-V to 18-V output voltage range," outputs below 0.8 V are not supported because the feedback amplifier cannot resolve errors below its reference voltage. Attempting sub-0.8-V regulation results in loss of control and unregulated output.
How does the EN pin function on the LM2738YSDX/NOPB?
The EN pin on the LM2738YSDX/NOPB controls device enable/disable: a logic-high voltage (>1.4 V) enables regulation; a logic-low voltage (<0.4 V) places the device in shutdown mode with 400-nA quiescent current. The pin must never exceed VIN + 0.3 V, and floating is prohibited-TI recommends tying to GND or VIN via a pull-down/pull-up resistor.
LM2738YSDX/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-WFDFN Exposed Pad
- 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:
- 550kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-WSON (3x3)
LM2738YSDX/NOPB FAQ
1.How can I place an order for LM2738YSDX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2738YSDX/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 LM2738YSDX/NOPB reliable?
The price and inventory of LM2738YSDX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2738YSDX/NOPB is usually 5 days.
3.What payment methods are accepted for LM2738YSDX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2738YSDX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2738YSDX/NOPB?
LM2738YSDX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2738YSDX/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 LM2738YSDX/NOPB?
For technical support, including LM2738YSDX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2738YSDX/NOPB requirements.
6.How does Aetrix verify that LM2738YSDX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2738YSDX/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 LM2738YSDX/NOPB meets industry standards.
7.What is the process for return or replacement of LM2738YSDX/NOPB?
All LM2738YSDX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2738YSDX/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 LM2738YSDX/NOPB part is unused and in its original packaging.
Return procedure for LM2738YSDX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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