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Texas Instruments LM2651MTCX-2.5/NOPB
- Part No.:
- LM2651MTCX-2.5/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM2651MTCX-2.5/NOPB.pdf
- Description:
- IC REG BUCK 2.5V 1.5A 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,325
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Product details
Overview
LM2651MTCX-2.5/NOPB from Texas Instruments is a 1.5 A synchronous step-down DC-DC switching regulator with fixed 2.5 V output, 300 kHz fixed-frequency current-mode PWM control, integrated high- and low-side MOSFETs (RDS(on) = 75 mΩ), and automatic hysteretic light-load mode for up to 97% peak efficiency - deployed in battery-powered PDAs, handheld scanners, and computer peripherals requiring stable 2.5 V rail generation from 4–14 V input.
For engineers reviewing the LM2651MTCX-2.5/NOPB datasheet, LM2651MTCX-2.5/NOPB pinout, LM2651MTCX-2.5/NOPB application, or LM2651MTCX-2.5/NOPB equivalent, key selection criteria include its 2.5 V ±2.8% output accuracy over temperature, 7 µA shutdown current, patented internal current sensing (no external sense resistor), 16-pin TSSOP package with separate AGND/PGND pins, and thermal shutdown at 165°C.
Technical Context
The LM2651MTCX-2.5/NOPB operates in constant-frequency (300 kHz) current-mode PWM under moderate-to-heavy loads (>100 mA), then automatically transitions to low-frequency hysteretic mode below the sleep threshold (100 mA) to sustain >80% efficiency at 15 mA. Its patented internal current-sensing circuit eliminates the need for an external sense resistor, improving noise immunity and reducing BOM count.
Control architecture integrates a transconductance error amplifier (Gm = 1250 µmho), adjustable soft-start via external capacitor on SD(SS) pin, input undervoltage lockout (UVLO = 3.85 V with 210 mV hysteresis), and cycle-by-cycle current limiting (typ. 2 A). The device uses bootstrap gate drive (VBOOT = 6.75 V) for the high-side MOSFET and features dedicated analog (AGND) and power (PGND) ground pins to isolate noise-sensitive feedback paths.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 2.5 V ±2.8% over full temperature range - ensures stable logic supply for 2.5 V I/O interfaces without external resistors. |
| Max Output Current | 1.5 A continuous - supports single-rail powering of microcontrollers, FPGAs, or interface ICs in portable systems. |
| Input Voltage Range | 4 V to 14 V - compatible with 5 V, 9 V, and 12 V wall adapters or multi-cell Li-ion/Li-poly battery packs. |
| Switching Frequency | 300 kHz fixed - enables use of compact, low-profile inductors (e.g., 4.7–10 µH) and reduces EMI compared to lower-frequency alternatives. |
| Peak Efficiency | 97% - achieved via synchronous rectification and low RDS(on) (75 mΩ) MOSFETs, minimizing conduction loss in high-current operation. |
| Shutdown Current | 7 µA - extends battery life in standby by disabling switching and bias circuits while retaining fast wake-up capability. |
| Thermal Shutdown | 165°C with 25°C hysteresis - protects against sustained overload or poor PCB thermal design without latch-up. |
Pinout & Package
LM2651MTCX-2.5/NOPB is housed in a 16-pin TSSOP package (5.00 mm × 4.40 mm body size) with exposed thermal pad (not electrically connected), optimized for surface-mount assembly and moderate-power thermal dissipation (θJA = 97.3°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2 SW | Switched-node output | Connects to source of internal high-side MOSFET and drain of low-side MOSFET; drives external inductor and catch diode path. |
| 3–5 VIN | Main power input | Accepts 4–14 V input; multiple pins reduce trace resistance and improve current handling for 1.5 A peak switch current. |
| 6 VCB | Bootstrap capacitor connection | Provides gate-drive voltage for high-side MOSFET; requires 0.1 µF ceramic capacitor between VCB and SW. |
| 7 AVIN | Analog supply input | Powers internal control circuitry and error amplifier; decoupled separately from VIN to minimize noise coupling into feedback loop. |
| 8 SD(SS) | Shutdown/Soft-Start control | Pulling <0.3 V disables regulator; external capacitor sets soft-start ramp time and prevents inrush current surges. |
| 9 FB | Feedback input | Monitors regulated 2.5 V output directly (internal resistor divider); no external components required for fixed-output version. |
| 10 COMP | Compensation network node | Connects to external RC network to stabilize control loop; critical for transient response and phase margin in PWM mode. |
| 11 NC | No internal connection | Unbonded pin; must remain unconnected to avoid parasitic coupling or mechanical stress on die bond wires. |
| 12, 13 AGND | Analog ground reference | Return path for FB, COMP, and error amplifier; isolated from PGND to prevent switching noise from corrupting regulation accuracy. |
| 14–16 PGND | Power ground return | High-current return for VIN, SW, and VCB; connects to input/output capacitors and inductor ground to minimize voltage spikes. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated synchronous MOSFETs | Eliminates external diode and reduces conduction loss - enables 97% efficiency without external rectifier. |
| Patented internal current sensing | Replaces external sense resistor - saves board space, cost, and improves noise immunity in current-mode control. |
| Automatic PWM-to-hysteretic transition | Maintains >80% efficiency down to 15 mA load - extends battery runtime in low-power standby modes. |
| Dual-ground architecture (AGND/PGND) | Separates analog and power return paths - preserves 2.5 V output accuracy under dynamic load transients. |
| Adjustable soft-start | Prevents input current surges during startup - avoids brownout in shared input rails and simplifies power sequencing. |
Applications
| Personal Digital Assistants (PDAs) | Computer Peripherals |
|---|---|
|
Use Scenario: Powering ARM-based application processors and NAND flash memory in handheld PDAs with dual-cell Li-ion batteries (7.2–8.4 V). IC Role / Device Role / Timing Role: Primary 2.5 V system rail regulator delivering up to 1.5 A with tight load regulation (0.3%) and low-noise AGND-referenced feedback. Use Value: Enables extended battery life via 97% peak efficiency and 7 µA shutdown current, while maintaining stable core voltage during burst-mode CPU operation. |
Use Scenario: Generating clean 2.5 V supply for USB 2.0 transceivers and EEPROMs in external HDD enclosures powered from 12 V adapter. IC Role / Device Role / Timing Role: Fixed-output buck converter with UVLO (3.85 V) and thermal shutdown (165°C) to ensure robust operation during ambient temperature excursions. Use Value: Delivers consistent 2.5 V I/O voltage across 4–14 V input range without external resistor programming, reducing design complexity and component count. |
| Battery-Powered Handheld Scanners | High-Efficiency 5-V Conversion Support |
|
Use Scenario: Supplying image sensor array and CMOS logic in barcode scanners using single-cell Li-ion (3.0–4.2 V) with boost-buck hybrid input conditioning. IC Role / Device Role / Timing Role: Secondary 2.5 V rail generator accepting conditioned 5–12 V intermediate bus; leverages 300 kHz frequency for compact magnetics. Use Value: Achieves >80% efficiency at 15 mA standby current - critical for multi-day battery life in intermittent-scan usage patterns. |
Use Scenario: Serving as post-regulator downstream of a 5 V buck converter to generate precise 2.5 V for analog front-end (AFE) circuits in industrial data loggers. IC Role / Device Role / Timing Role: Low-noise, high-PSRR point-of-load regulator with dedicated AGND pin to reject ripple from upstream 5 V switching stage. Use Value: Maintains 2.5 V output accuracy within ±2.8% despite 100 mVpp 5 V rail ripple, enabling accurate 12-bit ADC reference stability. |
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 low-side FET (requires external diode), higher quiescent current (12 mA) | Higher current headroom but lower light-load efficiency; lacks automatic hysteretic mode | Choose when >1.5 A peak load or higher switching frequency is required; accept trade-off in standby power and BOM complexity. |
| LM2678SD-2.5/NOPB | 2.5 A output, 260 kHz, external diode required, higher RDS(on) (120 mΩ), no sleep mode | Greater current capacity but 10–15% lower peak efficiency and no light-load optimization | Prefer for ruggedized industrial applications needing higher fault current margin; avoid where battery life is critical. |
Compared with TPS5430DDAR and LM2678SD-2.5/NOPB, LM2651MTCX-2.5/NOPB delivers superior light-load efficiency via automatic hysteretic mode and eliminates external diode losses through full synchronous integration - making it optimal for portable devices with mixed run/standby duty cycles.
Availability
LM2651MTCX-2.5/NOPB is available at Aetrix Electronics and suitable for personal digital assistants, handheld scanners, computer peripherals, and industrial data loggers requiring stable component supply with guaranteed long-term sourcing.
Supply support for LM2651MTCX-2.5/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 company headquartered in Dallas, Texas, specializing in analog, embedded processing, and power management ICs for industrial, automotive, and consumer markets.
The LM2651 product line was designed specifically for high-efficiency, low-quiescent-current DC-DC conversion in battery-powered portable electronics - emphasizing integrated power stages, intelligent light-load management, and simplified layout through dual-ground separation.
FAQ
What is the output voltage tolerance of the LM2651MTCX-2.5/NOPB over temperature?
The LM2651MTCX-2.5/NOPB provides a fixed 2.5 V output with ±2.8% tolerance over the full operating junction temperature range (−40°C to 125°C), as verified in the Electrical Characteristics table for the LM2651-2.5 variant. This specification ensures reliable operation of 2.5 V logic interfaces without external trimming or calibration, even under thermal stress conditions encountered in handheld enclosures.
Does the LM2651MTCX-2.5/NOPB require external compensation components?
Yes, the LM2651MTCX-2.5/NOPB requires external compensation components connected to the COMP pin (Pin 10) to stabilize the control loop. A typical network includes a series RC (e.g., 15 kΩ + 2.2 nF) and optionally a second capacitor (Cc2) to cancel the ESR zero of the output capacitor - details are provided in Section 8.2.2.7 of the SNVS032E datasheet.
Can the LM2651MTCX-2.5/NOPB operate with a 3.3 V input supply?
No, the LM2651MTCX-2.5/NOPB has a minimum recommended input voltage of 4 V per the Recommended Operating Conditions table. Operation below 4 V risks undervoltage lockout activation (VINUV rising edge = 3.85 V), causing premature shutdown. For 3.3 V input applications, a different regulator such as the TPS62130 is recommended.
What is the purpose of the separate AGND and PGND pins on the LM2651MTCX-2.5/NOPB?
The LM2651MTCX-2.5/NOPB uses separate AGND (Pins 12–13) and PGND (Pins 14–16) pins to isolate noise-sensitive analog circuitry (error amplifier, FB comparator) from high-current power return paths. This separation prevents switching transients from degrading output voltage accuracy and ensures stable regulation under dynamic load steps - a critical design feature confirmed in the Pin Functions table and Layout Guidelines section.
Is an external Schottky diode required when using the LM2651MTCX-2.5/NOPB?
Yes, Texas Instruments recommends an external Schottky diode (D1) connected from SW to PGND to prevent conduction through the intrinsic body diode of the internal low-side MOSFET during dead time. This improves efficiency by 1–2% and reduces noise, especially at higher input voltages and loads - guidance is explicitly stated in Section 8.2.2.8 of the SNVS032E datasheet.
LM2651MTCX-2.5/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):
- 2.5V
- 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-2.5/NOPB FAQ
1.How can I place an order for LM2651MTCX-2.5/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2651MTCX-2.5/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-2.5/NOPB reliable?
The price and inventory of LM2651MTCX-2.5/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-2.5/NOPB is usually 5 days.
3.What payment methods are accepted for LM2651MTCX-2.5/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2651MTCX-2.5/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2651MTCX-2.5/NOPB?
LM2651MTCX-2.5/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2651MTCX-2.5/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-2.5/NOPB?
For technical support, including LM2651MTCX-2.5/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2651MTCX-2.5/NOPB requirements.
6.How does Aetrix verify that LM2651MTCX-2.5/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2651MTCX-2.5/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-2.5/NOPB meets industry standards.
7.What is the process for return or replacement of LM2651MTCX-2.5/NOPB?
All LM2651MTCX-2.5/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2651MTCX-2.5/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-2.5/NOPB part is unused and in its original packaging.
Return procedure for LM2651MTCX-2.5/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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