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Texas Instruments LM2738YSD/NOPB
- Part No.:
- LM2738YSD/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 8-WFDFN Exposed Pad
- Datasheet:
-
LM2738YSD/NOPB.pdf
- Description:
- IC REG BUCK ADJ 1.5A 8WSON
- Quantity:
- Payment:
- Shipping:
Inventory:2,170
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Product details
Overview
LM2738YSD/NOPB from Texas Instruments is a monolithic 550-kHz, 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. Used in space-constrained point-of-load applications such as USB-powered devices and set-top boxes.
For engineers reviewing the LM2738YSD/NOPB datasheet, LM2738YSD/NOPB pinout, LM2738YSD/NOPB application, or LM2738YSD/NOPB equivalent, this page delivers verified technical context, real-world design meaning of key specs, validated pin functions, confirmed alternatives, and supply-chain support details - all specific to the LM2738YSD/NOPB variant (550 kHz, WSON-8).
Technical Context
The LM2738YSD/NOPB implements fixed-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 550-kHz switching frequency allows use of compact 2.2-µH inductors and ceramic capacitors while maintaining >90% efficiency at 12-VIN/3.3-VOUT/1.5-A loads.
It features cycle-by-cycle current limiting (2.9-A typical), thermal shutdown (165°C), undervoltage lockout (2.7-V rising threshold), and output overvoltage protection (16% above 0.8-V reference). The BOOST pin requires ≥2.5-V headroom above SW for NMOS gate drive, supporting VIN-, VOUT-, or Zener-derived bootstrap configurations.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switching Frequency | 550 kHz - enables use of ≤2.2-µH inductors and low-ESR ceramic output capacitors in minimal PCB area. |
| Max Output Current | 1.5 A - supports core power delivery for HDDs, DSL modems, and USB peripherals without external pass devices. |
| Input Voltage Range | 3 V to 20 V - accommodates 5-V, 12-V, and 19-V rails common in consumer and industrial equipment. |
| Output Voltage Range | 0.8 V to 18 V - programmable via resistor divider on FB pin; 0.8-V reference enables 1.0-V, 1.2-V, 1.5-V, 1.8-V, 3.3-V, and 5-V outputs. |
| NMOS RDS(ON) | 250 mΩ (typ) - minimizes conduction loss at full load; contributes to ≥90% peak efficiency at 12-VIN/3.3-VOUT. |
| Shutdown Current | 400 nA - preserves battery life in always-on or low-power standby modes of portable devices. |
| Feedback Reference | 0.800 V ±2% - ensures ±2% output voltage accuracy across temperature and line/load conditions. |
Pinout & Package
LM2738YSD/NOPB uses an 8-pin WSON package (NGQ) with 3.0 mm × 3.0 mm body and exposed thermal pad (DAP) connected to GND for enhanced thermal performance. Pin 1 is marked by a dot; top view orientation matches TI's standard WSON pinout.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - BOOST | Bootstrap supply input | Drives NMOS gate; requires ≥2.5-V headroom above SW; connects to CBOOST and D2 in typical layout. |
| 2 - VIN | Main power input | Supplies power stage; must be tied to VCC (Pin 3); bypassed with ≥10-µF ceramic capacitor near package. |
| 3 - VCC | Bias supply input | Internal regulator input; tied to VIN externally; supplies control circuitry and EN logic. |
| 4 - EN | Enable control | Logic-high (>1.4 V) enables operation; logic-low (<0.4 V) disables regulator and reduces IQ to 400 nA. |
| 5,7 - GND | Signal & power ground | Common return for feedback network, SW node, and thermal pad; low-impedance PCB connection required. |
| 6 - FB | Feedback input | Senses output voltage via resistor divider; regulates VOUT = 0.8 V × (1 + R1/R2); bias current <100 nA. |
| 8 - SW | Switch node output | Connects to inductor, catch diode, and CBOOST; swings between ~0 V (during TOFF) and VIN – IL×RDS(ON) (during TON). |
Key Features
| Feature | Design Value |
|---|---|
| Current-mode PWM control | Enables fast transient response and inherent cycle-by-cycle current limiting without external slope compensation. |
| 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 SW when FB exceeds 0.928 V (16% above 0.8-V reference), protecting downstream loads from fault conditions. |
| Thermal shutdown | Turns off SW at 165°C junction temperature; resumes operation after cooldown to ~150°C - prevents permanent damage. |
| Undervoltage lockout | Prevents operation below 2.7 V (rising) with 400-mV hysteresis; avoids erratic behavior during brownout or slow power-up. |
Applications
| USB-Powered Devices | Set-Top Boxes |
|---|---|
|
Use Scenario: Regulating 5-V USB input to 3.3-V or 1.8-V logic rails in streaming media adapters and IPTV receivers. IC Role / Device Role / Timing Role: Primary buck converter delivering regulated local power to SoC, memory, and interface ICs. Use Value: 550-kHz switching enables small 2.2-µH inductors and 22-µF X5R ceramics, reducing BOM cost and board area vs. lower-frequency alternatives. |
Use Scenario: Generating 1.2-V core voltage for MPEG decoder SoCs and 3.3-V I/O rails in cable/satellite receivers. IC Role / Device Role / Timing Role: High-efficiency point-of-load regulator with tight output tolerance for noise-sensitive video processing circuits. Use Value: 0.8-V ±2% reference and current-mode control maintain ±2% output accuracy across line, load, and temperature variations. |
| HDD Core Power | Battery-Powered Devices |
|
Use Scenario: Supplying 1.2-V/1.5-A core voltage to 2.5-inch SATA hard disk drive controllers during spin-up and active read/write. IC Role / Device Role / Timing Role: High-current buck regulator handling dynamic load steps up to 1.5 A with minimal output droop. Use Value: Cycle-by-cycle current limit (2.9-A typical) and thermal shutdown protect against short-circuit faults during mechanical shock events. |
Use Scenario: Converting single-cell Li-ion (3.0–4.2 V) or dual-cell alkaline (3–6 V) to stable 3.3-V system rail in portable test equipment and handheld scanners. IC Role / Device Role / Timing Role: Low-quiescent, high-efficiency DC-DC converter extending battery runtime in always-on monitoring systems. Use Value: 400-nA shutdown current and 90% peak efficiency at light loads preserve battery capacity during extended idle periods. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2738XSD/NOPB | 1.6-MHz switching frequency; same package, pinout, and feature set; higher frequency enables smaller inductors but increases switching loss at high VIN. | Better suited for ultra-compact designs where board space is more critical than efficiency at 12-V input. | Select LM2738XSD/NOPB only if 1.6-MHz operation is required; LM2738YSD/NOPB offers superior efficiency in mid-range input voltages (5–15 V). |
| TPS62231DRVR | 3-MHz fixed-frequency buck; 0.6-V reference; 0.9- to 6-V input; 1.8-A output; different pinout (6-pin WSON); no BOOST pin or external diode requirement. | Designed for simpler layouts with integrated high-side switch; lacks programmable UVLO and OVP features of LM2738YSD/NOPB. | Choose TPS62231DRVR for cost-sensitive, space-constrained apps needing minimal external components; LM2738YSD/NOPB preferred when robust fault protection and wide VIN range are mandatory. |
Compared with LM2738XSD/NOPB, the LM2738YSD/NOPB trades higher efficiency at medium input voltages for larger passive components; versus TPS62231DRVR, it provides greater design flexibility via external diode, adjustable UVLO/OVP, and wider input range - at the cost of two extra pins and layout complexity.
Availability
LM2738YSD/NOPB is available at Aetrix Electronics and suitable for USB-powered devices, set-top boxes, HDD core power, and battery-powered instrumentation requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM2738YSD/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 specializing in analog, embedded processing, and power management ICs, with decades of expertise in high-efficiency DC-DC conversion.
The LM2738YSD/NOPB belongs to TI's high-frequency buck regulator product line, designed specifically for space-constrained, high-current point-of-load applications demanding low quiescent current, robust protection, and simplified layout.
FAQ
What is the switching frequency of the LM2738YSD/NOPB?
The LM2738YSD/NOPB operates at a fixed 550-kHz switching frequency. This value is factory-set and not adjustable. It enables use of small surface-mount inductors (e.g., 2.2 µH) and ceramic output capacitors while maintaining high efficiency - typically >90% at 12-V input and 3.3-V/1.5-A output. The LM2738YSD/NOPB variant is distinct from the 1.6-MHz LM2738XSD/NOPB.
Does the LM2738YSD/NOPB require an external catch diode?
Yes, the LM2738YSD/NOPB requires an external Schottky catch diode (e.g., BAT54WS or CRS08) connected between SW and GND. Unlike synchronous buck regulators, it uses an internal NMOS high-side switch and relies on this external diode for inductor current freewheeling during the off-time. Omitting the diode will cause catastrophic failure.
What is the purpose of the BOOST pin on the LM2738YSD/NOPB?
The BOOST pin on the LM2738YSD/NOPB supplies gate drive voltage to the internal NMOS switch. It must be ≥2.5 V above the SW pin voltage during turn-on to ensure full enhancement. A bootstrap capacitor (typically 0.1 µF X7R) and diode (e.g., BAT54WS) form the charge pump. Improper BOOST voltage causes excessive RDS(ON), reduced efficiency, and thermal stress.
Can the LM2738YSD/NOPB operate from a 3.3-V input?
Yes, the LM2738YSD/NOPB supports input voltages as low as 3 V per its recommended operating conditions. However, achieving regulated output requires sufficient headroom: for a 3.3-V output, minimum input is ~4.0 V due to NMOS RDS(ON) drop and diode forward voltage. At 3.3-V input, maximum usable output is ~2.5 V. Always verify duty cycle and current limit margins using TI's Webench or datasheet equations.
How does the LM2738YSD/NOPB handle thermal overload?
The LM2738YSD/NOPB incorporates thermal shutdown that disables the internal NMOS switch when junction temperature exceeds 165°C. Operation resumes automatically once the die cools to ~150°C. This protects against sustained overload or poor PCB thermal design. For reliable continuous operation, maintain θJA ≤ 45.9°C/W (WSON package) using the exposed thermal pad tied to ≥2 cm² of 2-oz copper with ≥4 thermal vias.
LM2738YSD/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-WFDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- 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)
LM2738YSD/NOPB FAQ
1.How can I place an order for LM2738YSD/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2738YSD/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 LM2738YSD/NOPB reliable?
The price and inventory of LM2738YSD/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2738YSD/NOPB is usually 5 days.
3.What payment methods are accepted for LM2738YSD/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2738YSD/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2738YSD/NOPB?
LM2738YSD/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2738YSD/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 LM2738YSD/NOPB?
For technical support, including LM2738YSD/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2738YSD/NOPB requirements.
6.How does Aetrix verify that LM2738YSD/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2738YSD/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 LM2738YSD/NOPB meets industry standards.
7.What is the process for return or replacement of LM2738YSD/NOPB?
All LM2738YSD/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2738YSD/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 LM2738YSD/NOPB part is unused and in its original packaging.
Return procedure for LM2738YSD/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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