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Texas Instruments LM2651MTCX-1.8/NOPB
- Part No.:
- LM2651MTCX-1.8/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM2651MTCX-1.8/NOPB.pdf
- Description:
- IC REG BUCK 1.8V 1.5A 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,348
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Product details
Overview
LM2651MTCX-1.8/NOPB from Texas Instruments is a 1.5 A synchronous step-down DC-DC switching regulator in a 16-pin TSSOP package, delivering fixed 1.8 V output from 4–14 V input. It achieves up to 97% efficiency via internal MOSFETs (RDS(on) = 75 mΩ), operates at 300 kHz fixed frequency, and enters hysteretic sleep mode below 100 mA load to maintain >80% efficiency at 15 mA - ideal for battery-powered PDAs and handheld scanners.
For engineers reviewing the LM2651MTCX-1.8/NOPB datasheet, LM2651MTCX-1.8/NOPB pinout, LM2651MTCX-1.8/NOPB application, or LM2651MTCX-1.8/NOPB equivalent, key selection criteria include its patented current-sense architecture (no external sense resistor), 7 µA shutdown current, input UVLO (3.85 V rising threshold), thermal shutdown (165 °C), and compatibility with low-profile external components due to high-frequency operation.
Technical Context
The LM2651MTCX-1.8/NOPB uses current-mode PWM control with cycle-by-cycle current limiting (2 A typical) and automatic transition to hysteretic light-load mode. Its internal high-side and low-side MOSFETs are driven by a bootstrap-regulated gate circuit (VBOOT = 6.7 V typical), eliminating external driver complexity.
Control loop stability relies on transconductance error amplifier (GM = 1250 µmho) with COMP pin compensation, feedback reference of 1.238 V, and soft-start ramp generated by internal 11 µA current source into external capacitor - enabling controlled inrush current and power sequencing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output voltage | Fixed 1.8 V ±2% over full temperature range - ensures stable core supply for low-voltage microcontrollers and ASICs. |
| Input voltage range | 4 V to 14 V - supports single-cell Li-ion (4.2 V max) through 12 V industrial rails without external pre-regulation. |
| Max output current | 1.5 A continuous - sufficient for powering DSPs, FPGAs, and multi-rail PMICs in portable instrumentation. |
| Switching frequency | 300 kHz ±10% - enables use of compact 4.7–10 µH inductors and low-ESR ceramic output capacitors. |
| Quiescent current | 1.6 mA typical - minimizes standby drain in always-on battery systems such as medical monitors. |
| Shutdown current | 7 µA maximum - reduces system-level leakage during deep sleep, extending shelf life of sealed devices. |
| Efficiency peak | 97% at mid-load - achieved via synchronous rectification and low RDS(on) MOSFETs, reducing thermal load in confined enclosures. |
| Thermal shutdown | 165 °C with 25 °C hysteresis - protects against sustained overload or poor PCB heatsinking without requiring external thermal sensors. |
Pinout & Package
LM2651MTCX-1.8/NOPB is housed in a 16-pin TSSOP package (5.00 mm × 4.40 mm body size) with exposed thermal pad (not electrically connected). Pin layout optimized for minimal high-di/dt loop area between VIN, SW, and PGND.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2 - SW | Switched-node output | Connects to inductor and Schottky diode anode; carries high di/dt current - requires short, wide trace to minimize EMI and voltage spikes. |
| 3–5 - VIN | Main power input | Distributes 4–14 V input to internal regulators and high-side switch - must be decoupled with low-ESR ceramic + bulk capacitor near pins. |
| 6 - VCB | Bootstrap capacitor connection | Supplies gate drive voltage for high-side MOSFET; requires 0.1 µF X7R ceramic capacitor placed adjacent to pin. |
| 7 - SD(SS) | Shutdown/soft-start control | Pulling below 0.3 V disables regulator; external capacitor sets soft-start time - prevents input surge and enables power sequencing. |
| 9 - FB | Feedback input | Monitors output via resistive divider; internal 1.238 V reference enables precise regulation - sensitive to noise, requires dedicated trace. |
| 10 - COMP | Compensation network | Connects external RC network to stabilize control loop - determines phase margin and transient response to load steps. |
| 11 - NC | No internal connection | Unbonded pad - must remain unconnected and may be tied to ground for mechanical stability only. |
| 12, 13 - AGND | Analog ground reference | Provides low-noise return for feedback, error amplifier, and bias circuits - isolated from power ground to prevent coupling. |
| 14–16 - PGND | Power ground return | Carries high pulsed currents from MOSFETs and inductor - must connect directly to thermal pad and input/output capacitor grounds. |
Key Features
| Feature | Design Value |
|---|---|
| Patented current sensing | Eliminates external sense resistor - reduces BOM cost, PCB area, and noise susceptibility while maintaining accurate current-mode control. |
| Synchronous rectification | Internal low-RDS(on) (75 mΩ) MOSFETs replace external Schottky diode - improves efficiency by 5–10% and removes reverse-recovery losses. |
| Hysteretic light-load mode | Automatically transitions below 100 mA load - maintains >80% efficiency at 15 mA without external control logic or mode-select pins. |
| Adjustable soft-start | Programmed via single capacitor on SD(SS) pin - controls inrush current and enables staggered power-up across multiple rails in complex systems. |
| Integrated protection | Includes undervoltage lockout (3.85 V), cycle-by-cycle current limit (2 A), and thermal shutdown (165 °C) - eliminates need for discrete protection ICs. |
| Bootstrap gate drive | On-chip charge pump generates 6.7 V gate voltage - ensures full enhancement of high-side MOSFET across full input range without external boost circuitry. |
Applications
| Personal Digital Assistants (PDAs) | Computer Peripherals |
|---|---|
Use Scenario: Powering ARM-based application processors and SRAM in handheld PDA units with single-cell Li-ion battery. IC Role / Device Role / Timing Role: Primary 1.8 V core voltage regulator delivering regulated output with fast transient response to processor DVFS events. Use Value: 97% peak efficiency extends runtime per charge; 7 µA shutdown current preserves battery during weeks of standby. |
Use Scenario: Generating 1.8 V supply for USB controller ICs and interface logic in external HDD enclosures and docking stations. IC Role / Device Role / Timing Role: Secondary DC-DC converter stepping down 5 V USB bus or 12 V adapter input to low-noise logic rail. Use Value: Fixed 1.8 V output eliminates need for external feedback resistors; TSSOP package fits tight board space behind USB connectors. |
| Battery-Powered Scanners | High-Efficiency 5-V Conversion |
Use Scenario: Supplying image sensor and FPGA in handheld barcode scanners powered by two AA alkaline cells (2.4–3.2 V). IC Role / Device Role / Timing Role: Boost-buck capable regulator (with external diode) providing stable 1.8 V despite declining battery voltage. Use Value: Wide 4–14 V input range accommodates boosted battery voltage; hysteretic mode sustains >85% efficiency down to 15 mA idle current. |
Use Scenario: Converting 12 V industrial supply to 1.8 V for digital I/O banks in programmable logic controllers (PLCs). IC Role / Device Role / Timing Role: High-current point-of-load regulator replacing linear LDOs to reduce heat generation in enclosed chassis. Use Value: 1.5 A capability and 97% efficiency cut power dissipation by >80% versus 12 V-to-1.8 V LDO, eliminating forced-air cooling. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS5430DDAR | 3 A output, 500 kHz switching, no integrated bootstrap diode - requires external bootstrap capacitor and higher gate drive overhead. | Higher current and frequency suit more demanding loads but increase EMI filtering complexity and component count. | Choose when >1.5 A output or faster transient response is required; verify layout compatibility with larger TSSOP-8 footprint. |
| MP2315DJ-LF-Z | 1.5 A, 2 MHz switching, integrated high-side/low-side MOSFETs, but only 2.5–6 V input range - incompatible with 12 V inputs. | Optimized for USB-powered devices; lacks UVLO hysteresis and thermal shutdown flag output of LM2651MTCX-1.8/NOPB. | Prefer for space-constrained 5 V systems where 2 MHz allows sub-2 mm inductors; avoid for 12 V industrial or automotive inputs. |
Compared with TPS5430DDAR and MP2315DJ-LF-Z, LM2651MTCX-1.8/NOPB offers broader input range (4–14 V), proven thermal robustness (165 °C shutdown), and lower quiescent current (1.6 mA vs ≥3 mA), making it optimal for long-life battery and wide-input industrial applications where reliability trumps raw speed or current headroom.
Availability
LM2651MTCX-1.8/NOPB is available at Aetrix Electronics and suitable for personal digital assistants, computer peripherals, battery-powered scanners, and high-efficiency 5-V conversion systems requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for LM2651MTCX-1.8/NOPB 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-efficiency DC-DC conversion and industrial-grade reliability.
The LM2651 product line was designed specifically for battery-powered portable electronics requiring ultra-high efficiency across wide load ranges - emphasizing low quiescent current, integrated protection, and simplified external component requirements.
FAQ
What is the output voltage tolerance of the LM2651MTCX-1.8/NOPB over temperature and load?
The LM2651MTCX-1.8/NOPB delivers a fixed 1.8 V output with ±2% tolerance over the full operating junction temperature range (−40 °C to 125 °C) and load current from 15 mA to 1.5 A. At 25 °C and 900 mA load, the typical output is 1.800 V, with min/max values of 1.761 V and 1.836 V respectively - verified per Electrical Characteristics Table 6.5 in the SNVS032E datasheet.
Does the LM2651MTCX-1.8/NOPB require an external Schottky diode?
Yes, TI recommends an external Schottky diode (D1) connected from SW to PGND for the LM2651MTCX-1.8/NOPB. Although it integrates synchronous MOSFETs, the diode prevents conduction through the intrinsic body diode of the low-side FET during dead time - improving efficiency by 1–2% and reducing EMI, especially at higher input voltages and loads.
What is the minimum input voltage required for the LM2651MTCX-1.8/NOPB to start switching?
The LM2651MTCX-1.8/NOPB begins operation when input voltage rises above the undervoltage lockout (UVLO) threshold of 3.85 V (typical, rising edge), with 210 mV hysteresis. Below this level, the device remains disabled regardless of SD(SS) pin state - ensuring reliable startup only when sufficient input energy is available to sustain regulation.
How does the LM2651MTCX-1.8/NOPB achieve current-mode control without an external sense resistor?
The LM2651MTCX-1.8/NOPB implements patented internal current sensing that monitors high-side MOSFET conduction via bond-wire resistance and process-matched transistor structures - eliminating the need for an external sense resistor. This reduces component count, PCB area, and noise pickup while maintaining accurate cycle-by-cycle current limiting at 2 A typical.
Can the LM2651MTCX-1.8/NOPB operate with a 12 V input and deliver 1.5 A continuously?
Yes, the LM2651MTCX-1.8/NOPB is fully rated for 12 V input and 1.5 A continuous output current. Thermal data shows RθJA = 97.3 °C/W in TSSOP-16; at 12 V input and 1.8 V/1.5 A output, power dissipation is ~1.2 W, resulting in ~117 °C junction rise above ambient - well within the 125 °C max operating junction temperature when ambient is ≤25 °C and PCB copper area is adequate.
LM2651MTCX-1.8/NOPB 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):
- 1.8V
- 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-1.8/NOPB FAQ
1.How can I place an order for LM2651MTCX-1.8/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2651MTCX-1.8/NOPB 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-1.8/NOPB reliable?
The price and inventory of LM2651MTCX-1.8/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2651MTCX-1.8/NOPB is usually 5 days.
3.What payment methods are accepted for LM2651MTCX-1.8/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2651MTCX-1.8/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2651MTCX-1.8/NOPB?
LM2651MTCX-1.8/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2651MTCX-1.8/NOPB 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-1.8/NOPB?
For technical support, including LM2651MTCX-1.8/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2651MTCX-1.8/NOPB requirements.
6.How does Aetrix verify that LM2651MTCX-1.8/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2651MTCX-1.8/NOPB 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-1.8/NOPB meets industry standards.
7.What is the process for return or replacement of LM2651MTCX-1.8/NOPB?
All LM2651MTCX-1.8/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2651MTCX-1.8/NOPB, 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-1.8/NOPB part is unused and in its original packaging.
Return procedure for LM2651MTCX-1.8/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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