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Texas Instruments LM2736XMKX
- Part No.:
- LM2736XMKX
- Manufacturer:
- Texas Instruments
- Package:
- SOT-23-6 Thin, TSOT-23-6
- Datasheet:
-
LM2736XMKX.pdf
- Description:
- IC REG BUCK ADJ 750MA SOT23
- Quantity:
- Payment:
- Shipping:
Inventory:1,998
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Product details
Overview
LM2736XMKX from Texas Instruments is a monolithic, current-mode PWM step-down DC-DC regulator in a 6-pin Thin SOT package. It delivers up to 750 mA output current with 1.6 MHz fixed switching frequency, 1.25 V internal reference (±2%), 350 mΩ NMOS switch RDS(ON), and operates from 3.0 V to 18 V input. It enables compact point-of-load regulation in space-constrained USB-powered devices and notebook computers.
For engineers reviewing the LM2736XMKX datasheet, LM2736XMKX pinout, LM2736XMKX application, or LM2736XMKX equivalent, key selection considerations include its 1.6 MHz switching frequency enabling ultra-small external inductors, 30 nA shutdown current for battery longevity, internal soft-start for controlled ramp-up, and thermal shutdown protection at 165°C junction temperature.
Technical Context
The LM2736XMKX uses constant-frequency current-mode control with internal compensation, eliminating need for external loop components. Its 1.6 MHz oscillator supports minimum on-times down to 13 ns, enabling stable regulation down to 1.25 V output across the full 3–18 V input range.
It integrates undervoltage lockout (UVLO) with 2.74 V turn-on threshold and 440 mV hysteresis, cycle-by-cycle current limiting at 1.5 A (typ), and output overvoltage protection triggered at FB = 1.1 × VREF. The BOOST pin requires ≥2.5 V above SW for optimal gate drive, with recommended VBOOST–VSW between 2.5 V and 5.5 V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switching Frequency | 1.6 MHz - enables use of ≤4.7 µH inductors and chip-scale ceramic capacitors, minimizing PCB area. |
| Output Current | 750 mA - sufficient for core power in HDDs, set-top boxes, and USB peripherals without external pass devices. |
| Input Voltage Range | 3.0 V to 18 V - supports wide-input applications including automotive infotainment and industrial 12 V rails. |
| Feedback Reference | 1.25 V ±2% - sets output voltage via external resistor divider; enables precise 1.25–16 V programmable VOUT. |
| RDS(ON) | 350 mΩ (typ) - limits conduction loss at 750 mA load; contributes to >90% peak efficiency at 5 VIN/3.3 VOUT. |
| Shutdown Current | 30 nA (typ) - preserves battery life in always-on portable systems; enables true low-power sleep modes. |
| Soft-Start Time | ~200 µs - linearly ramps internal error amplifier reference to limit inrush current during startup. |
Pinout & Package
LM2736XMKX is housed in a 6-pin Thin SOT (DDC) package measuring 2.90 mm × 1.60 mm, optimized for high-density layouts and thermal performance on 2- or 4-layer boards.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BOOST | Bootstrap supply | Drives NMOS gate; requires external capacitor to SW; must exceed SW by ≥2.5 V for full 750 mA capability. |
| GND | Signal & power ground | Reference for feedback network and internal circuits; place bottom feedback resistor adjacent to minimize noise coupling. |
| FB | Voltage feedback input | Monitors output via resistor divider; regulates VOUT to 1.25 V at FB; sensitive to layout-induced noise. |
| EN | Enable control | Logic-high (>1.8 V) enables operation; logic-low (<0.4 V) enters 30 nA shutdown; must not exceed VIN + 0.3 V. |
| VIN | Main input supply | Accepts 3–18 V; requires local 10 µF ceramic bypass capacitor near pin to suppress switching transients. |
| SW | Power switch node | Connects to inductor, catch diode, and BOOST capacitor; carries high di/dt; requires short, low-inductance routing. |
Key Features
| Feature | Design Value |
|---|---|
| Internal Compensation | Eliminates external compensation network - reduces BOM count and design iteration time for stable 1.6 MHz operation. |
| Current-Mode Control | Provides inherent cycle-by-cycle current limiting and fast transient response to load steps without external sensing. |
| Thermal Shutdown | Disables switch at 165°C junction temperature and auto-restarts at ~150°C - protects against sustained overload or poor heatsinking. |
| Output Overvoltage Protection | Shuts off NMOS when FB exceeds 1.375 V (1.1 × 1.25 V) - prevents damage to downstream 3.3 V or 1.8 V logic. |
| Undervoltage Lockout | Prevents startup until VIN ≥2.74 V and holds operation until VIN drops below 2.3 V - avoids brownout instability during power ramp. |
Applications
| Local Point of Load Regulation | Core Power in HDDs |
|---|---|
Use Scenario: Regulating 3.3 V or 5 V from a 12 V or 5 V system rail directly at an FPGA or microcontroller power pin. IC Role / Device Role / Timing Role: Primary buck converter delivering regulated DC power; no timing or signal integrity role. Use Value: 1.6 MHz switching allows <2 mm² total solution size with 4.7 µH inductor and 10 µF MLCCs, reducing board area vs. lower-frequency alternatives. | Use Scenario: Supplying 1.2 V or 1.5 V core voltage to HDD controller ASICs with tight transient requirements. IC Role / Device Role / Timing Role: High-efficiency DC-DC converter with fast load-step response due to current-mode architecture. Use Value: 750 mA continuous output and 1.5 A current limit ensure reliable operation during spindle motor startup surges. |
| USB Powered Devices | Notebook Computers |
Use Scenario: Converting 5 V USB power to 3.3 V or 1.8 V for embedded sensors, audio codecs, or Wi-Fi modules. IC Role / Device Role / Timing Role: Standalone step-down regulator with ultra-low shutdown current for battery-backed operation. Use Value: 30 nA shutdown current extends runtime in suspend mode; internal soft-start prevents USB port overcurrent trips. | Use Scenario: Generating auxiliary voltages (e.g., 1.5 V DDR memory, 3.3 V I/O) from main 12 V or 19 V adapter input. IC Role / Device Role / Timing Role: Compact, thermally robust buck regulator for space-limited motherboard VRM sections. Use Value: Thin SOT-6 package (2.9 × 1.6 mm) and 158.1°C/W θJA enable placement near heat-sensitive components without thermal derating. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2736YMKX | 550 kHz switching frequency, higher max duty cycle (96% vs. 92%), slightly lower quiescent current in active mode (1.5 mA vs. 2.2 mA). | Better suited for higher output voltages (e.g., 5 V from 12 V) where lower frequency improves efficiency; requires larger inductors/caps. | Select LM2736YMKX when board area is less constrained and efficiency at light loads is prioritized over footprint. |
| TPS62231DRVR | 3 MHz switching, 600 mA output, 2.05 V to 6.5 V input, integrated synchronous rectifier, 17 µA quiescent current. | Optimized for single-cell Li-ion (3.0–4.2 V) inputs and low-voltage outputs (≥1.0 V); lacks UVLO hysteresis and OVP. | Choose TPS62231DRVR for battery-powered systems needing highest light-load efficiency and smallest possible inductor (1.0 µH typical). |
Compared with LM2736YMKX and TPS62231DRVR, LM2736XMKX uniquely balances 1.6 MHz high-frequency operation with 3–18 V wide input range and integrated protection features (OVP, UVLO hysteresis, thermal shutdown), making it optimal for industrial and USB-C PD adapter-derived rails where input variability and reliability are critical.
Availability
LM2736XMKX is available at Aetrix Electronics and suitable for local point-of-load regulation, core power in HDDs, and USB-powered devices requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.
Supply support for LM2736XMKX 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 specializing in analog, embedded processing, and power management ICs, with leadership in high-reliability, high-efficiency DC-DC conversion solutions.
The LM2736XMKX belongs to TI's Thin SOT buck regulator product line, designed specifically for space-constrained, wide-input applications demanding high power density, robust protection, and minimal external component count.
FAQ
What is the maximum recommended VBOOST–VSW voltage for reliable operation of the LM2736XMKX?
The LM2736XMKX specifies a maximum VBOOST–VSW of 5.5 V per the Absolute Maximum Ratings table. Exceeding this risks internal gate oxide stress and long-term reliability degradation. For best efficiency and full 750 mA capability, maintain VBOOST–VSW between 2.5 V and 5.5 V. The LM2736XMKX datasheet confirms this limit applies across the full operating temperature range (−40°C to +125°C).
Does the LM2736XMKX require an external catch diode, and why?
Yes, the LM2736XMKX requires an external Schottky catch diode (e.g., MBRM110L) connected from SW to VOUT. Because it uses an NMOS high-side switch without synchronous rectification, the diode provides the return path for inductor current during the switch-off period. Omitting it causes catastrophic failure due to unclamped inductive kickback. The LM2736XMKX datasheet explicitly shows D1 in all typical application circuits and specifies 0.3 V forward voltage as optimal for efficiency.
How does the LM2736XMKX achieve 750 mA output with only a 350 mΩ internal switch?
The LM2736XMKX achieves 750 mA continuous output by combining its 350 mΩ NMOS RDS(ON) with 1.6 MHz switching, which minimizes inductor size and ripple current, thereby reducing RMS conduction losses. At 5 VIN/3.3 VOUT, conduction loss is ~195 mW (I²R), well within the thermal limits of the Thin SOT-6 package (θJA = 158.1°C/W). The LM2736XMKX datasheet confirms 750 mA is validated across −40°C to +125°C ambient with proper PCB copper area.
Can the LM2736XMKX be used with ceramic output capacitors exclusively?
Yes, the LM2736XMKX is fully compatible with ceramic output capacitors (e.g., X5R/X7R MLCCs), as confirmed in Section 8.2.1.2.3 of the datasheet. Its current-mode control and internal compensation ensure stability with low-ESR ceramics. A typical 10 µF, 6.3 V X5R capacitor (e.g., TDK C3216X5ROJ106M) meets ripple and transient requirements without added bulk or ESR-related losses.
What protection features are integrated into the LM2736XMKX?
The LM2736XMKX integrates five key protections: (1) cycle-by-cycle current limit (1.5 A typ), (2) thermal shutdown (165°C trip, 150°C restart), (3) output overvoltage protection (trips at FB = 1.375 V), (4) undervoltage lockout with hysteresis (2.74 V ON, 2.3 V OFF), and (5) 30 nA shutdown current to prevent battery drain. All are documented in Sections 7.3 and 7.4 of the LM2736XMKX datasheet and require no external components.
LM2736XMKX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- SOT-23-6 Thin, TSOT-23-6
- 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):
- 18V
- Voltage - Output (Min/Fixed):
- 1.25V
- Voltage - Output (Max):
- 16V
- Current - Output:
- 750mA
- Frequency - Switching:
- 1.6MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-THIN
LM2736XMKX FAQ
1.How can I place an order for LM2736XMKX through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2736XMKX 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 LM2736XMKX reliable?
The price and inventory of LM2736XMKX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2736XMKX is usually 5 days.
3.What payment methods are accepted for LM2736XMKX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2736XMKX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2736XMKX?
LM2736XMKX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2736XMKX 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 LM2736XMKX?
For technical support, including LM2736XMKX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2736XMKX requirements.
6.How does Aetrix verify that LM2736XMKX is sourced from the original manufacturer or authorized distributors?
All LM2736XMKX 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 LM2736XMKX meets industry standards.
7.What is the process for return or replacement of LM2736XMKX?
All LM2736XMKX units undergo pre-shipment inspection (PSI). If there is an issue with LM2736XMKX, 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 LM2736XMKX part is unused and in its original packaging.
Return procedure for LM2736XMKX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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