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Texas Instruments LM2651MTCX-3.3
- Part No.:
- LM2651MTCX-3.3
- Manufacturer:
- Texas Instruments
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM2651MTCX-3.3.pdf
- Description:
- IC REG BUCK 3.3V 1.5A 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,374
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Product details
Overview
LM2651MTCX-3.3 from Texas Instruments is a 1.5 A synchronous step-down DC-DC switching regulator in a 16-pin TSSOP package, delivering fixed 3.3 V output from 4–14 V input, achieving up to 97% efficiency and operating in current-mode PWM or light-load hysteretic mode for battery-powered PDAs, handheld scanners, and peripherals.
For engineers reviewing the LM2651MTCX-3.3 datasheet, LM2651MTCX-3.3 pinout, LM2651MTCX-3.3 application, or LM2651MTCX-3.3 equivalent, key selection considerations include its 300-kHz fixed-frequency oscillator, integrated MOSFETs with 75 mΩ RDS(on), 7 µA shutdown current, patented current-sensing architecture eliminating external sense resistors, and sleep-mode hysteresis of 60 mV at 3.3 V output.
Technical Context
The LM2651MTCX-3.3 implements current-mode PWM control with cycle-by-cycle current limiting (2 A typical) and automatic transition to low-power hysteretic mode below 100 mA load. Its internal 300-kHz oscillator enables compact external components, while the patented current-sensing circuit replaces external sense resistors by monitoring MOSFET conduction voltage drop.
It integrates high-side and low-side N-channel MOSFETs with 75 mΩ RDS(on), uses bootstrap gate drive (VCB pin), includes undervoltage lockout (3.8–3.95 V rising threshold), thermal shutdown at 165°C, and soft-start via external capacitor on SD(SS) pin - all optimized for stable 3.3 V rail generation in space-constrained portable systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3 V ±1.1% over full temperature range; ensures stable logic supply for 3.3-V microcontrollers and interfaces. |
| Input Voltage Range | 4 V to 14 V; supports single-cell Li-ion (4.2 V max) through multi-cell alkaline or 12-V industrial rails. |
| Max Output Current | 1.5 A continuous; sufficient for powering ARM Cortex-M microcontrollers, USB peripherals, and display drivers. |
| Switching Frequency | 300 kHz fixed; allows use of small 4.7–10 µH inductors and low-ESR ceramic output capacitors. |
| Efficiency | Up to 97% at mid-load; maintains >80% even at 15 mA, extending battery life in standby and active modes. |
| Shutdown Current | 7 µA typical; reduces system quiescent power during deep sleep or off-state without external disconnect. |
| Sleep Mode Hysteresis | 60 mV at 3.3 V output; defines 30-mV window around nominal output to prevent oscillation between PWM/hysteretic modes. |
Pinout & Package
LM2651MTCX-3.3 is housed in a 16-pin TSSOP (PW) package measuring 5.00 mm × 4.40 mm, with exposed thermal pad connected to PGND for enhanced thermal performance in high-current operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2 SW | Switched-node output | Connects to inductor and Schottky diode anode; carries high dv/dt switching waveform requiring tight layout. |
| 3–5 VIN | Main power input | Accepts 4–14 V; requires local 10–47 µF low-ESR input capacitor tied directly to PGND pins. |
| 6 VCB | Bootstrap capacitor connection | Drives high-side MOSFET gate; requires 0.1 µF ceramic capacitor between VCB and SW for reliable turn-on. |
| 7 AVIN | Analog supply input | Powers internal error amplifier and control logic; decoupled separately from VIN to reduce noise coupling. |
| 8 SD(SS) | Shutdown/soft-start control | Pulling below 0.3 V disables regulator; external capacitor sets controlled ramp-up of output voltage at startup. |
| 9 FB | Feedback input | Monitors output via resistor divider; internal reference is 1.238 V, enabling precise 3.3 V regulation. |
| 10 COMP | Compensation network | Connects external RC network to stabilize loop response; critical for transient performance and phase margin. |
| 11 NC | No internal connection | Not bonded; must remain unconnected to avoid parasitic coupling or mechanical stress. |
| 12, 13 AGND | Analog ground | Reference for feedback and error amplifier; routed separately from PGND to minimize noise injection. |
| 14–16 PGND | Power ground | Return path for high-current switch node and inductor; tied to thermal pad for optimal heat dissipation. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated synchronous MOSFETs | Eliminates external diode and reduces conduction loss; 75 mΩ high-side RDS(on) enables high efficiency at 1.5 A. |
| Patented current sensing | Replaces external sense resistor with MOSFET VDS-based sensing, saving board area and improving noise immunity. |
| Auto-switching PWM/hysteretic modes | Maintains >80% efficiency down to 15 mA load without external mode control or bias circuitry. |
| Adjustable soft-start | External capacitor on SD(SS) pin controls inrush current and prevents input rail sag during startup sequencing. |
| Thermal shutdown with hysteresis | Shuts down at 165°C and restarts at 140°C, preventing thermal runaway in enclosed or high-ambient environments. |
Applications
| Personal Digital Assistants (PDAs) | Computer Peripherals |
|---|---|
Use Scenario: Powering ARM9-based PDA mainboard with LCD backlight, touch controller, and SD card interface. IC Role / Device Role / Timing Role: Primary 3.3 V system rail regulator delivering 1.2 A average load with burst peaks to 1.5 A. Use Value: 97% peak efficiency extends usable runtime per charge; 7 µA shutdown current preserves battery during suspend-to-RAM. |
Use Scenario: Supplying 3.3 V to USB 2.0 hub ICs, LED status indicators, and EEPROM in docking stations. IC Role / Device Role / Timing Role: Secondary regulated rail derived from 5 V USB upstream or 12 V adapter input. Use Value: Fixed 3.3 V output eliminates need for external feedback resistors; TSSOP package fits dense peripheral PCB layouts. |
| Battery-Powered Handheld Scanners | High-Efficiency 5-V to 3.3-V Conversion |
Use Scenario: Converting two AA/AAA cells (2.4–3.2 V) boosted to 5 V, then stepped down to clean 3.3 V for CMOS image sensor and FPGA. IC Role / Device Role / Timing Role: Final-stage point-of-load regulator ensuring low-noise, ripple-free 3.3 V for analog sensor front-end. Use Value: Sleep-mode hysteresis of 60 mV prevents mode chatter during intermittent scan bursts; AGND/PGND separation minimizes sensor noise. |
Use Scenario: Replacing discrete buck converter designs in legacy 5 V systems upgrading to 3.3 V I/O standards. IC Role / Device Role / Timing Role: Drop-in replacement for LM257x or similar controllers, integrating switches and current sensing. Use Value: Eliminates 2 external MOSFETs and 1 sense resistor; 16-pin TSSOP footprint matches common layout templates for fast redesign. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS62130ARGTR | 3-MHz switching frequency, 95% efficiency, 3-A output, 2.95–6 V input; smaller 16-pin QFN (3 × 3 mm). | Optimized for ultra-compact 3.3 V rails from single Li-ion; lacks programmable soft-start and has higher IQ (17 µA). | Preferred when board space is constrained and input voltage is limited to ≤6 V. |
| LM2678SD-3.3/NOPB | 1-A output, 260-kHz frequency, external MOSFETs required, 50 mV load regulation, TO-263 package. | Higher thermal mass for industrial ambient; requires external high-side FET and sense resistor, increasing BOM count. | Chosen when higher reliability under sustained 85°C ambient or long-term availability is prioritized over integration. |
Compared with TPS62130ARGTR and LM2678SD-3.3/NOPB, the LM2651MTCX-3.3 offers superior light-load efficiency via hysteretic mode, eliminates external sense components, and provides wider 4–14 V input flexibility - making it optimal for multi-battery or adapter-powered portable systems where standby life and design simplicity are critical.
Availability
LM2651MTCX-3.3 is available at Aetrix Electronics and suitable for personal digital assistants, handheld scanners, and computer peripherals requiring stable component supply across production lifecycles and varying input source configurations.
Supply support for LM2651MTCX-3.3 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 headquartered in Dallas, Texas, specializing in analog, embedded processing, and power management ICs for industrial, automotive, and consumer markets.
The LM2651 product line delivers highly integrated synchronous buck regulators targeting battery-operated portable electronics where efficiency across wide load ranges and minimal external component count are essential design goals.
FAQ
What is the maximum input voltage rating for the LM2651MTCX-3.3?
The LM2651MTCX-3.3 has an absolute maximum input voltage rating of 15 V. Operation above this level risks permanent damage. The recommended operating range is 4 V to 14 V, aligning with common battery chemistries and industrial supply rails. Exceeding 14 V may trigger undervoltage lockout recovery instability or degrade long-term reliability.
Does the LM2651MTCX-3.3 require an external Schottky diode?
Yes, TI recommends an external Schottky diode (D1) connected from SW to PGND for the LM2651MTCX-3.3. This prevents conduction through the intrinsic body diode of the low-side MOSFET during dead time, reducing power loss by 1–2% and improving efficiency - especially at higher input voltages and loads.
How does the sleep mode function in the LM2651MTCX-3.3?
The LM2651MTCX-3.3 enters sleep mode automatically when load current drops below 100 mA. In this mode, both MOSFETs turn off, allowing output voltage to decay until reaching the lower hysteretic threshold (3.27 V), then resumes PWM operation. This achieves >80% efficiency at 15 mA while eliminating external mode-control circuitry.
What is the purpose of the VCB pin on the LM2651MTCX-3.3?
VCB on the LM2651MTCX-3.3 supplies the bootstrap voltage for driving the high-side N-channel MOSFET gate. A 0.1 µF ceramic capacitor must be placed between VCB and SW to generate ~6.7 V gate drive above SW potential, ensuring full enhancement and low RDS(on) during high-side conduction.
Can the LM2651MTCX-3.3 be used with a 3.6 V Li-ion battery input?
Yes, the LM2651MTCX-3.3 supports 3.6 V Li-ion battery input - but only when fully charged (up to 4.2 V). Its minimum operating input is 4 V, so operation below that voltage triggers undervoltage lockout. For single-cell Li-ion systems requiring deeper discharge, consider pairing with a boost pre-regulator or selecting a 2.7–5.5 V input alternative.
LM2651MTCX-3.3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4V
- Voltage - Input (Max):
- 14V
- Voltage - Output (Min/Fixed):
- 3.3V
- Voltage - Output (Max):
- -
- Current - Output:
- 1.5A
- Frequency - Switching:
- 300kHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-TSSOP
LM2651MTCX-3.3 FAQ
1.How can I place an order for LM2651MTCX-3.3 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2651MTCX-3.3 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 LM2651MTCX-3.3 reliable?
The price and inventory of LM2651MTCX-3.3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2651MTCX-3.3 is usually 5 days.
3.What payment methods are accepted for LM2651MTCX-3.3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2651MTCX-3.3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2651MTCX-3.3?
LM2651MTCX-3.3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2651MTCX-3.3 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 LM2651MTCX-3.3?
For technical support, including LM2651MTCX-3.3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2651MTCX-3.3 requirements.
6.How does Aetrix verify that LM2651MTCX-3.3 is sourced from the original manufacturer or authorized distributors?
All LM2651MTCX-3.3 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 LM2651MTCX-3.3 meets industry standards.
7.What is the process for return or replacement of LM2651MTCX-3.3?
All LM2651MTCX-3.3 units undergo pre-shipment inspection (PSI). If there is an issue with LM2651MTCX-3.3, 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 LM2651MTCX-3.3 part is unused and in its original packaging.
Return procedure for LM2651MTCX-3.3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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