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Texas Instruments LM2694SDX
- Part No.:
- LM2694SDX
- Manufacturer:
- Texas Instruments
- Package:
- 10-WFDFN Exposed Pad
- Datasheet:
-
LM2694SDX.pdf
- Description:
- IC REG BUCK ADJ 600MA 10WSON
- Quantity:
- Payment:
- Shipping:
Inventory:3,452
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Product details
Overview
LM2694SDX from Texas Instruments is a 30V, 600 mA step-down switching regulator with integrated N-channel buck switch and constant-on-time control architecture. It operates from 8V–30V input, delivers adjustable output voltage via external resistors, features no-loop-compensation design, and supports up to 1 MHz switching frequency in thermally enhanced WSON-10 package. It is used in high-voltage post-regulation for telecom and industrial power supplies.
For engineers reviewing the LM2694SDX datasheet, LM2694SDX pinout, LM2694SDX application, or LM2694SDX equivalent, key selection considerations include its valley current limit (0.62 A), 2.5 V feedback reference, bootstrap-driven gate drive, thermal shutdown at 175°C, and RON/SD programmable on-time control - all critical for stable POL conversion under wide VIN and transient load conditions.
Technical Context
The LM2694SDX implements a constant-on-time (COT) control scheme where on-time is determined by VIN and an external RON resistor, enabling near-constant switching frequency across line and load variations. Its regulation loop compares FB voltage against a precision 2.5 V internal reference without requiring external compensation components.
Current limiting occurs during off-time via ISEN pin sensing, with a nominal valley current threshold of 0.62 A. The device integrates a startup regulator (VCC = 7.0 V ±0.4 V), BST bootstrap circuitry (0.022 µF SW-to-BST capacitor), and dual protection: overvoltage shutdown (FB > 2.9 V) and thermal shutdown (175°C activation).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 8 V to 30 V - supports wide-range industrial and telecom inputs without pre-regulation. |
| Output Current | Up to 600 mA - continuous load capability limited by valley current sense at 0.62 A. |
| Switching Frequency | Up to 1 MHz - programmable via RON resistor; enables compact magnetics and fast transient response. |
| Feedback Reference | 2.5 V - precise internal reference sets output via R1/R2 divider; enables accurate adjustable VOUT. |
| Thermal Shutdown | 175°C activation - protects against sustained overload or poor heatsinking in WSON-10 package. |
| Startup Regulator | VCC = 7.0 V ±0.4 V - powers internal circuitry; eliminates need for external bias supply. |
| Current Sense | Valley current limit at 0.62 A - provides short-circuit protection with smooth transition into constant-current mode. |
Pinout & Package
LM2694SDX is packaged in a thermally enhanced 10-pin WSON (3 mm × 3 mm) with exposed pad. The exposed pad must be soldered to PCB ground plane for optimal thermal performance (θJA = 33°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (SW) | Switching Node | Connects to inductor, freewheeling diode cathode, and BST capacitor - carries high dv/dt switching waveform. |
| 2 (BST) | Bootstrap Supply | Accepts 0.022 µF capacitor from SW - charges internal high-side gate driver during off-time. |
| 3 (ISEN) | Current Sense Output | Sinks recirculating inductor current during off-time - sets valley current limit at 0.62 A. |
| 4 (SGND) | Current Sense Ground | Return path for ISEN current - isolated from main RTN to avoid noise coupling into sense path. |
| 5 (RTN) | Main Circuit Ground | Ground return for VCC, FB, SS, RON/SD, and internal logic - connects to system ground plane. |
| 6 (FB) | Voltage Feedback Input | Compares output voltage (via R1/R2) to 2.5 V reference - no external compensation required. |
| 7 (SS) | Softstart Control | Charged by 12 µA internal current source - controls output ramp rate and reduces inrush stress. |
| 8 (RON/SD) | On-Time Programming / Shutdown | Resistor from VIN sets on-time; grounding disables regulator and resets softstart. |
| 9 (VCC) | Startup Regulator Output | 7.0 V regulated supply - powers internal circuits; accepts external bias to reduce dissipation. |
| 10 (VIN) | Main Input Supply | 8–30 V input - bypassed with low-ESR ceramic capacitor close to pin and RTN. |
Key Features
| Feature | Design Value |
|---|---|
| No loop compensation required | Enables stable operation with minimal external components and eliminates tuning effort for feedback stability. |
| Ultra-fast transient response | Constant-on-time architecture ensures immediate on-pulse initiation when FB falls below 2.5 V - critical for POL loads with sudden current steps. |
| Integrated start-up regulator | VCC = 7.0 V output eliminates need for auxiliary bias rail - simplifies system-level power architecture. |
| Valley current limit at 0.62 A | Provides robust short-circuit protection without foldback, maintaining predictable current limiting during fault conditions. |
| Thermally enhanced WSON-10 | 3 mm × 3 mm package with exposed pad achieves θJA = 33°C/W - supports 600 mA operation without forced air. |
Applications
| High-Efficiency Point-of-Load Regulator | Non-Isolated Telecom Buck Regulator |
|---|---|
Use Scenario: Powering FPGA I/O banks or ASIC core rails from intermediate 12 V or 24 V distribution bus in telecom line cards. IC Role / Device Role / Timing Role: Primary buck converter delivering tightly regulated 1.2 V–5 V outputs with fast load-step response and minimal external components. Use Value: Eliminates need for external compensation and reduces BOM count while sustaining >90% efficiency at 300–600 mA loads. | Use Scenario: Generating 3.3 V or 5 V bias rails from 48 V telecom rectified input in remote radio units (RRUs) and base station subsystems. IC Role / Device Role / Timing Role: High-input-voltage step-down regulator operating directly from -48 V derived 24–30 V rails with built-in UVLO and thermal protection. Use Value: Supports wide VIN range (8–30 V) and withstands 33 V transients - avoids need for front-end pre-regulator stages. |
| Secondary High-Voltage Post Regulator | Industrial Sensor Signal Chain Bias Supply |
Use Scenario: Down-converting 24 V or 30 V industrial PLC backplane voltage to 5 V or 3.3 V for microcontrollers and interface ICs. IC Role / Device Role / Timing Role: Robust secondary regulator handling variable input due to long cable drops and motor-induced transients. Use Value: Integrated 30 V N-channel switch and 175°C thermal shutdown ensure reliable operation in harsh environments. | Use Scenario: Providing clean, low-noise 3.3 V supply for analog front-ends (ADCs, op-amps, sensors) in factory automation modules. IC Role / Device Role / Timing Role: Efficient DC-DC converter with low quiescent current (0.8 mA typical) and precise 2.5 V reference for stable feedback. Use Value: Achieves <100 mVpp output ripple using standard ceramic capacitors - meets noise-sensitive analog supply requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2694MX/NOPB | TSSOP-14 package (vs. WSON-10); identical electrical specs and pinout mapping except NC pins differ. | Larger footprint and higher θJA (40°C/W); less suitable for space-constrained designs but easier hand-soldering. | Select LM2694MX/NOPB when board assembly uses through-hole or TSSOP-compatible processes and thermal margin exceeds 10°C/W. |
| TPS54202DRCT | 4.5–28 V input; 2 A output; integrated FETs; requires external compensation; 2.5 V reference. | Higher current rating and lower VIN min; lacks valley current limit - uses peak current mode with slope compensation. | Choose TPS54202DRCT when >600 mA load or tighter VIN range (e.g., 12 V bus) is required, and layout allows compensation network. |
Compared with LM2694MX/NOPB, LM2694SDX offers superior thermal performance and smaller footprint; compared with TPS54202DRCT, it trades higher current capability for simpler design (no compensation) and wider VIN range - making LM2694SDX optimal for fixed 600 mA, high-input-voltage, low-component-count applications.
Availability
LM2694SDX is available at Aetrix Electronics and suitable for high-efficiency point-of-load (POL) regulators, non-isolated telecom buck converters, and secondary high-voltage post regulators requiring stable component supply across extended temperature and input voltage ranges.
Supply support for LM2694SDX 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 technologies, with decades of expertise in high-reliability power conversion ICs.
The LM2694 product line targets cost-sensitive, high-voltage DC-DC applications in telecom infrastructure and industrial systems - emphasizing simplicity, robustness, and minimal external component count.
FAQ
What is the maximum input voltage rating for LM2694SDX?
The absolute maximum input voltage (VIN to RTN) for LM2694SDX is 33 V, with recommended operating range of 8 V to 30 V. Exceeding 33 V risks permanent damage. Transient spikes within this limit are tolerated, but sustained operation above 30 V violates the specified operating ratings and may degrade reliability or trigger overvoltage protection on internal nodes like BST or VCC.
Does LM2694SDX require external compensation components?
No, LM2694SDX does not require external compensation components. Its constant-on-time control architecture eliminates the need for loop compensation networks, simplifying design and improving transient response. The feedback loop relies solely on the 2.5 V internal reference and external R1/R2 resistor divider - verified across temperature and load in TI's SNVS444A datasheet.
How is the output voltage set on LM2694SDX?
The output voltage of LM2694SDX is set using two external resistors (R1 and R2) forming a voltage divider from VOUT to FB and FB to RTN. The formula is VOUT = 2.5 V × (R1 + R2)/R2. For example, equal 2.5 kΩ resistors yield 5 V output. This relationship is confirmed in the Electrical Characteristics table and Application Information section of the LM2694SDX datasheet.
What is the purpose of the ISEN pin on LM2694SDX?
The ISEN pin on LM2694SDX serves as the valley current sense output during the buck switch off-time. It sinks the recirculating inductor current through an internal 180 mΩ sense resistor, enabling detection of current exceeding 0.62 A. This triggers valley current limiting - holding the switch off until current subsides - providing short-circuit protection without foldback behavior, as documented in the Functional Description and Electrical Characteristics sections.
Can LM2694SDX operate with an externally applied VCC voltage?
Yes, LM2694SDX supports externally applied VCC voltage between 8 V and 14 V to reduce internal power dissipation. When an external supply is diode-connected to VCC, the internal start-up regulator shuts off. However, the sum of external VCC and VIN must not exceed 47 V, and the external supply must be stable and well-bypassed - per Figure 10 and "Start-Up Regulator, VCC" section of the LM2694SDX datasheet.
LM2694SDX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 10-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):
- 8V
- Voltage - Input (Max):
- 30V
- Voltage - Output (Min/Fixed):
- 2.5V
- Voltage - Output (Max):
- 24V
- Current - Output:
- 600mA
- Frequency - Switching:
- 1MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-WSON (3x3)
LM2694SDX FAQ
1.How can I place an order for LM2694SDX through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2694SDX 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 LM2694SDX reliable?
The price and inventory of LM2694SDX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2694SDX is usually 5 days.
3.What payment methods are accepted for LM2694SDX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2694SDX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2694SDX?
LM2694SDX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2694SDX 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 LM2694SDX?
For technical support, including LM2694SDX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2694SDX requirements.
6.How does Aetrix verify that LM2694SDX is sourced from the original manufacturer or authorized distributors?
All LM2694SDX 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 LM2694SDX meets industry standards.
7.What is the process for return or replacement of LM2694SDX?
All LM2694SDX units undergo pre-shipment inspection (PSI). If there is an issue with LM2694SDX, 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 LM2694SDX part is unused and in its original packaging.
Return procedure for LM2694SDX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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