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Texas Instruments LM2694MTX
- Part No.:
- LM2694MTX
- Manufacturer:
- Texas Instruments
- Package:
- 14-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM2694MTX.pdf
- Description:
- IC REG BUCK ADJ 600MA 14TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,740
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Product details
Overview
LM2694MTX 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 to 30V input, delivers adjustable output voltage via external resistors, features no loop compensation, and supports up to 1 MHz switching frequency - used in high-voltage post-regulation for telecom and industrial power supplies.
For engineers reviewing the LM2694MTX datasheet, LM2694MTX pinout, LM2694MTX application, or LM2694MTX equivalent, key selection criteria include its valley current limit (0.62 A), thermal shutdown (175°C), VCC startup regulator (7 V), BST bootstrap operation, and WSON-10 package with exposed pad for thermal management.
Technical Context
The LM2694MTX employs a constant on-time control scheme where tON is determined by VIN and RON/SD resistor value, enabling stable switching frequency across line and load variations. Its regulation relies on a 2.5 V internal reference at FB and requires no external compensation due to inherent stability.
Current limiting occurs during off-time via ISEN pin sensing recirculating inductor current, with nominal threshold of 0.62 A and fast response (<150 ns). The integrated start-up regulator provides 7 V at VCC (6.6–7.4 V) with 9 mA current limit and 5.7 V UVLO, while thermal shutdown activates at 175°C with 20°C hysteresis.
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 Capability | 600 mA continuous - sufficient for point-of-load bias rails in FPGA, DSP, and analog subsystems |
| Switching Frequency | Up to 1 MHz - enables compact magnetics and low-profile designs with minimal EMI filtering |
| Valley Current Limit | 0.62 A ±12% - provides robust short-circuit protection without foldback or frequency collapse |
| FB Regulation Threshold | 2.5 V ±2% - precise reference enables accurate output setting with standard resistor ratios |
| VCC Startup Regulator | 7.0 V ±0.4 V - powers internal circuitry directly from VIN; eliminates need for auxiliary bias supply |
| Thermal Shutdown | 175°C activation, 155°C recovery - protects against sustained overload or poor heatsinking |
| Junction-to-Ambient θJA | 33°C/W (WSON-10, 0 LFPM) - validated thermal performance with exposed pad soldered to PCB ground plane |
Pinout & Package
The LM2694MTX is housed in a thermally enhanced 3 mm × 3 mm WSON-10 package with exposed pad (DSC0010A), requiring connection to PCB ground plane for optimal thermal dissipation and EMI reduction.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 SW | Switching Node | Drives external inductor and freewheeling diode; connects to BST capacitor; handles high dv/dt transitions |
| 2 BST | Bootstrap Supply | Charged from SW during off-time via internal diode; supplies gate drive for high-side N-FET |
| 3 ISEN | Current Sense Output | Sinks recirculating inductor current during off-time; sets 0.62 A valley current limit |
| 4 SGND | Sense Ground Return | Provides dedicated return path for current-sense resistor; isolates sense node from power ground noise |
| 5 RTN | Main Circuit Ground | Reference for all internal regulators and comparators except current-sense path |
| 6 FB | Voltage Feedback Input | Compares output divider voltage to 2.5 V reference; no compensation required |
| 7 SS | Softstart Control | Internal 12 µA current source ramps voltage to 2.5 V; controls output rise time and inrush |
| 8 RON/SD | On-Time Set / Shutdown | Resistor from VIN sets tON; grounding disables regulator and discharges SS |
| 9 VCC | Startup Regulator Output | 7 V regulated supply for internal logic and gate drive; can be externally biased to reduce dissipation |
| 10 VIN | Main Input Supply | Accepts 8–30 V; bypassed locally with ceramic capacitor to minimize input ripple and EMI |
Key Features
| Feature | Design Value |
|---|---|
| No loop compensation required | Enables stable regulation with minimal external components - reduces BOM count and layout sensitivity |
| Constant on-time control | Maintains stable switching frequency across 8–30 V input and full load range without feedback loop tuning |
| Integrated 7 V startup regulator | Eliminates need for external bias supply; supports direct connection to high-voltage rails up to 30 V |
| Valley current limit at 0.62 A | Provides graceful transition to constant-current mode under overload - avoids destructive peak currents |
| Thermal shutdown with hysteresis | Automatically resets at 155°C after 175°C trip - prevents latch-up and enables self-recovery in intermittent overloads |
| WSON-10 with exposed pad | 3×3 mm footprint with 33°C/W thermal resistance - optimized for space-constrained industrial and telecom PCBs |
Applications
| High-Efficiency Point-of-Load Regulator | Non-Isolated Telecom Buck Regulator |
|---|---|
Use Scenario: Powering FPGA core or I/O banks from a 12 V or 24 V intermediate bus in base station or network equipment. IC Role / Device Role / Timing Role: Primary DC-DC buck controller delivering tightly regulated 1.2 V or 3.3 V with fast transient response. Use Value: No loop compensation simplifies design; 0.62 A current limit ensures safe operation during FPGA configuration surges. | Use Scenario: Generating 5 V bias rail from 48 V telecom supply in optical line cards or remote radio units. IC Role / Device Role / Timing Role: High-input-voltage step-down regulator operating in continuous conduction mode at full load. Use Value: 30 V rated switch withstands 48 V transients; constant on-time control maintains stable 250–500 kHz frequency despite line variation. |
| Secondary High-Voltage Post Regulator | Industrial Sensor Bias Supply |
Use Scenario: Down-converting 24 V factory automation bus to 3.3 V for microcontroller and interface ICs. IC Role / Device Role / Timing Role: Robust, thermally efficient buck regulator handling wide ambient temperature swings. Use Value: Exposed-pad WSON-10 package achieves 33°C/W θJA; thermal shutdown prevents failure in enclosed enclosures. | Use Scenario: Providing isolated 5 V supply for analog front-end sensors in motor drives or PLC modules. IC Role / Device Role / Timing Role: Compact, low-noise bias regulator powering precision ADCs and op-amps. Use Value: 2.5 V FB reference tolerance (±2%) ensures output accuracy; softstart minimizes sensor startup disturbance. |
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; higher θJA (40°C/W); same electrical specs and pinout mapping except NC pins | Better suited for prototyping or manual assembly; less thermally efficient than WSON-10 | Select LM2694MX/NOPB when board-level rework or through-hole compatibility is prioritized over thermal density |
| TPS54202DRCT | 2 A output; 4.5–28 V input; integrated FETs; 2.5 V reference; requires external compensation | Higher current capability but narrower input range; more complex loop design | Choose TPS54202DRCT only if >600 mA load or tighter input range (e.g., 12 V systems) justifies added complexity |
Compared with LM2694MX/NOPB, the LM2694MTX offers superior thermal performance in a smaller footprint; versus TPS54202DRCT, it trades higher current for simpler design, wider input range, and no compensation - making LM2694MTX optimal for cost-sensitive, high-input-voltage, moderate-current POL applications.
Availability
LM2694MTX is available at Aetrix Electronics and suitable for high-efficiency point-of-load (POL) regulation, non-isolated telecom buck conversion, and secondary high-voltage post-regulation requiring stable component supply and long-term industrial availability.
Supply support for LM2694MTX 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 LM2694MTX belongs to TI's high-voltage buck regulator product line, designed specifically for efficient, compact, and easy-to-implement DC-DC conversion in telecom, industrial, and automotive auxiliary power systems.
FAQ
What is the maximum input voltage rating for the LM2694MTX?
The LM2694MTX has an absolute maximum input voltage (VIN to RTN) of 33 V, with recommended operating range from 8 V to 30 V. This allows direct use with 24 V industrial buses and 48 V telecom systems with appropriate transient protection. Exceeding 33 V risks permanent damage to the internal N-channel buck switch and startup regulator. Always verify input surge conditions and select input capacitors accordingly.
Does the LM2694MTX require external compensation components?
No, the LM2694MTX does not require external compensation components. Its constant on-time control architecture and internal 2.5 V reference eliminate the need for loop compensation networks. This simplifies design, reduces BOM count, and improves reliability - confirmed in the SNVS444A datasheet Section 1 "Features" and Functional Description. The LM2694MTX achieves stable regulation and ultra-fast transient response inherently.
How is the output voltage set on the LM2694MTX?
The output voltage of the LM2694MTX 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, selecting R1 = R2 = 2.5 kΩ yields 5 V output. The FB pin draws <1 nA bias current, minimizing resistor-divider error. This method is specified in the Electrical Characteristics table and Application Information section of the LM2694MTX datasheet.
What is the purpose of the RON/SD pin on the LM2694MTX?
The RON/SD pin on the LM2694MTX serves dual functions: it sets the buck switch on-time via an external resistor to VIN (RON), and acts as a shutdown control - grounding this pin disables the regulator, discharges the SS capacitor, and reduces quiescent current to 90–180 µA. The shutdown threshold is 0.45–1.2 V rising, with 35 mV hysteresis. This pin is detailed in the Pin Descriptions and Functional Description sections of the LM2694MTX datasheet.
Can the LM2694MTX operate without an external bootstrap capacitor?
No, the LM2694MTX cannot operate without an external bootstrap capacitor. A 0.022 µF ceramic capacitor must be placed between BST and SW pins to supply gate drive voltage for the internal N-channel buck switch. During each off-time, this capacitor recharges from VCC via an internal diode. Omitting C4 causes gate drive failure, resulting in no switching action or erratic operation - explicitly required in the Pin Descriptions and Typical Application Circuit sections of the LM2694MTX datasheet.
LM2694MTX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 14-TSSOP (0.173", 4.40mm 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):
- 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:
- 14-TSSOP
LM2694MTX FAQ
1.How can I place an order for LM2694MTX through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2694MTX 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 LM2694MTX reliable?
The price and inventory of LM2694MTX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2694MTX is usually 5 days.
3.What payment methods are accepted for LM2694MTX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2694MTX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2694MTX?
LM2694MTX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2694MTX 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 LM2694MTX?
For technical support, including LM2694MTX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2694MTX requirements.
6.How does Aetrix verify that LM2694MTX is sourced from the original manufacturer or authorized distributors?
All LM2694MTX 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 LM2694MTX meets industry standards.
7.What is the process for return or replacement of LM2694MTX?
All LM2694MTX units undergo pre-shipment inspection (PSI). If there is an issue with LM2694MTX, 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 LM2694MTX part is unused and in its original packaging.
Return procedure for LM2694MTX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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