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Texas Instruments LM2694MT
- Part No.:
- LM2694MT
- Manufacturer:
- Texas Instruments
- Package:
- 14-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM2694MT.pdf
- Description:
- IC REG BUCK ADJ 600MA 14TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,484
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Product details
Overview
LM2694MT 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 resistor divider feedback (2.5 V reference), and features no loop compensation, valley current limiting at 0.62 A, and thermal shutdown - used in high-voltage POL regulation for telecom and industrial power supplies.
For engineers reviewing the LM2694MT datasheet, LM2694MT pinout, LM2694MT application, or LM2694MT equivalent, key selection considerations include its WSON-10 thermally enhanced package, 1 MHz max switching frequency, RON/SD programmable on-time, BST bootstrap operation, and absence of external compensation requirements.
Technical Context
The LM2694MT employs a constant-on-time control scheme where on-time is determined by VIN and an external RON resistor, enabling stable switching frequency across line and load variations. Its valley current limit detection (0.62 A) triggers off-time extension during overload, transitioning smoothly into constant-current mode without foldback.
It integrates a start-up regulator (7 V ±0.4 V, 9 mA current-limited) powering internal circuitry and gate drive, with UVLO thresholds at 5.7 V (rising) and 5.55 V (falling). The FB pin compares against a precision 2.5 V reference, while an independent 2.9 V overvoltage comparator terminates on-time immediately if exceeded.
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 rails in FPGA I/O, DSP core, or analog subsystems |
| Switching Frequency | Up to 1 MHz - enables compact magnetics and low-profile designs; frequency remains stable vs. load/input |
| Current Limit Threshold | 0.62 A (valley-sensed) - provides short-circuit protection with controlled foldback-free current limiting |
| Feedback Reference Voltage | 2.500 V ±1.5% - sets output voltage via external resistive divider; <100 nA bias current minimizes divider error |
| Thermal Shutdown | 175 °C activation with 20 °C hysteresis - protects against sustained overloads or poor heatsinking |
| VCC Regulator Output | 7.0 V ±0.4 V - powers internal logic and gate driver; externally bypassed with ≥0.1 µF ceramic capacitor |
Pinout & Package
LM2694MT is housed in a thermally enhanced 10-pin WSON package (3 mm × 3 mm) with exposed pad for PCB ground connection. The exposed pad significantly reduces θJA to 33 °C/W (0 LFPM), improving power dissipation capability in space-constrained applications.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 SW | Switching Node | Connection to inductor, freewheeling diode cathode, and BST capacitor - carries high dv/dt and pulsed current |
| 2 BST | Bootstrap Supply | Connects 0.022 µF capacitor to SW; charges via internal diode during off-time to sustain high-side gate drive |
| 3 ISEN | Valley Current Sense | Sinks recirculating inductor current during off-time; internal sense resistor sets 0.62 A current limit threshold |
| 4 SGND | Current Sense Ground | Return path for ISEN current; must be routed separately from RTN to avoid noise coupling into current sensing |
| 5 RTN | Circuit Ground | Main ground return for all internal circuitry except current sense path; connects to system ground plane |
| 6 FB | Voltage Feedback Input | Compares output voltage (via R1/R2 divider) to 2.5 V reference; requires ≥25 mV ripple for stable regulation |
| 7 SS | Soft-Start Control | Internal 12 µA current source charges external capacitor to ramp reference and prevent inrush current |
| 8 RON/SD | On-Time Programming / Shutdown | Resistor to VIN sets on-time; grounding disables regulator and discharges SS capacitor |
| 9 VCC | Startup Regulator Output | 7 V regulated supply for internal circuits; can be externally biased to reduce dissipation when VIN > 8 V |
| 10 VIN | Main Input Supply | Accepts 8–30 V; requires local 0.1 µF + bulk capacitance; absolute max 33 V |
Key Features
| Feature | Design Value |
|---|---|
| No external loop compensation required | Eliminates 3–4 passive components and design iteration; simplifies layout and improves transient response |
| Constant on-time control architecture | Maintains stable switching frequency across 8–30 V input and full load range without frequency droop |
| Integrated start-up regulator (7 V) | Enables direct connection to high-voltage rails up to 30 V; eliminates need for external bias supply |
| Valley current limit at 0.62 A | Provides accurate, temperature-stable short-circuit protection with graceful transition to constant-current mode |
| Thermally enhanced WSON-10 package | 33 °C/W junction-to-ambient thermal resistance enables 600 mA operation in compact 3×3 mm footprint |
Applications
| Telecom Secondary Post-Regulator | Industrial Point-of-Load Converter |
|---|---|
Use Scenario: Regulating 48 V intermediate bus down to 5 V or 3.3 V for line card ASICs or interface ICs in telecom equipment. IC Role / Device Role / Timing Role: Primary DC-DC buck controller providing isolated secondary-side regulation with fast transient response to burst traffic loads. Use Value: Eliminates need for external compensation and reduces component count versus traditional voltage-mode controllers, lowering BOM cost and board area. | Use Scenario: Powering microcontroller I/O banks or sensor signal chains in factory automation PLCs operating from 24 V DC industrial rails. IC Role / Device Role / Timing Role: High-input-voltage step-down regulator delivering stable, low-noise 3.3 V or 5 V with built-in thermal and overcurrent protection. Use Value: Operates reliably across wide input range (8–30 V) and ambient temperatures (−40°C to +125°C junction), reducing qualification effort. |
| Non-Isolated High-Voltage Buck | FPGA Core/I/O Bias Supply |
Use Scenario: Generating 1.2 V or 1.8 V from 12 V or 24 V rail in embedded vision systems or motor drives where isolation is not required. IC Role / Device Role / Timing Role: Efficient non-isolated buck converter with valley current limiting to protect against inductor saturation or output shorts. Use Value: Integrated 30 V N-channel switch and bootstrap driver enable single-chip solution - no external MOSFET or gate driver needed. | Use Scenario: Providing clean, sequenced 1.2 V core and 2.5 V I/O supplies for Xilinx Spartan or Intel Cyclone FPGAs in edge computing modules. IC Role / Device Role / Timing Role: Dual-rail POL regulator using separate LM2694MT instances with soft-start timing coordinated via SS pin capacitors. Use Value: Independent soft-start (SS pin) and shutdown (RON/SD pin) allow precise power sequencing without external supervisors. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2694MM | TSSOP-14 package (θJA = 40 °C/W); same electrical specs and pinout mapping but different pin numbering and NC placement | Less thermally efficient than LM2694MT; preferred only when TSSOP footprint or hand-soldering is required | Select LM2694MM only if board layout constraints prohibit WSON-10 or require through-hole-compatible assembly. |
| TPS54202DRCT | 4.5–28 V input, 2 A output, integrated FETs, current-mode control, requires external compensation; 3×3 mm WSON-10 package | Higher current rating and lower input voltage limit; lacks valley current limit and constant-on-time simplicity | Choose TPS54202DRCT when >600 mA load or tighter output voltage tolerance (<±1%) is required; LM2694MT remains optimal for 8–30 V, 600 mA, minimal-BOM designs. |
Compared with LM2694MM and TPS54202DRCT, the LM2694MT uniquely combines 30 V input capability, valley current limiting, and zero-compensation operation in a thermally superior WSON-10 package - making it the most direct fit for high-input-voltage, moderate-current POL applications where simplicity and thermal performance are prioritized.
Availability
LM2694MT is available at Aetrix Electronics and suitable for telecom secondary regulators, industrial point-of-load converters, and non-isolated high-voltage buck applications requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM2694MT 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 designing analog, embedded processing, and connectivity products for industrial, automotive, and communications markets.
The LM2694MT belongs to TI's high-voltage buck regulator product line, engineered specifically for efficient, low-component-count DC-DC conversion from 8 V to 30 V inputs in space- and thermal-constrained applications.
FAQ
What is the maximum input voltage rating for the LM2694MT?
The LM2694MT has an absolute maximum input voltage (VIN to RTN) rating of 33 V, with recommended operating range from 8 V to 30 V. Exceeding 33 V risks permanent damage. The device includes internal protection features such as VCC under-voltage lockout and thermal shutdown, but these do not override the 33 V absolute maximum rating. Always observe this limit in both steady-state and transient conditions when designing with the LM2694MT.
Does the LM2694MT require external compensation components?
No, the LM2694MT does not require external compensation components. Its constant-on-time control architecture eliminates the need for loop compensation networks (e.g., type-II or type-III compensators), simplifying design and reducing BOM count. This architecture inherently provides ultra-fast transient response and stable operation across line and load variations - a confirmed feature documented in the LM2694MT datasheet (SNVS444A) under "No Loop Compensation Required".
How is the output voltage set on the LM2694MT?
The output voltage of the LM2694MT is set using an external resistive divider connected to the FB pin. The internal reference voltage is 2.500 V, so VOUT = 2.5 × (R1 + R2) / R2, where R1 connects between VOUT and FB, and R2 connects between FB and RTN. Standard 1% resistors in the 1–10 kΩ range are recommended; for example, R1 = R2 = 2.5 kΩ yields 5 V output. The FB pin draws less than 100 nA, minimizing divider current error.
What is the function of the RON/SD pin on the LM2694MT?
The RON/SD pin on the LM2694MT serves dual functions: it programs the buck switch on-time via an external resistor to VIN, and acts as a shutdown control. When pulled below 0.8 V (typically grounded), the LM2694MT enters shutdown mode - disabling the on-timer, grounding the SS pin, and reducing quiescent current to 90–180 µA. During normal operation, the pin voltage ranges from 1.5 V to 3.0 V depending on VIN and RON value, directly determining tON per the formula in the LM2694MT datasheet.
Can the LM2694MT operate with an externally supplied VCC voltage?
Yes, the LM2694MT supports externally applied VCC voltage between 8 V and 14 V. Doing so disables the internal start-up regulator, reducing power dissipation and improving efficiency when VIN exceeds ~10 V. The external VCC must be diode-or'd to avoid backfeed, and the sum of external VCC and VIN must not exceed 47 V (BST-to-VCC absolute max). This feature is explicitly validated in the LM2694MT datasheet Figure 10 and Electrical Characteristics table.
LM2694MT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 14-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- 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
LM2694MT FAQ
1.How can I place an order for LM2694MT through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2694MT 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 LM2694MT reliable?
The price and inventory of LM2694MT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2694MT is usually 5 days.
3.What payment methods are accepted for LM2694MT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2694MT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2694MT?
LM2694MT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2694MT 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 LM2694MT?
For technical support, including LM2694MT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2694MT requirements.
6.How does Aetrix verify that LM2694MT is sourced from the original manufacturer or authorized distributors?
All LM2694MT 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 LM2694MT meets industry standards.
7.What is the process for return or replacement of LM2694MT?
All LM2694MT units undergo pre-shipment inspection (PSI). If there is an issue with LM2694MT, 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 LM2694MT part is unused and in its original packaging.
Return procedure for LM2694MT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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