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Texas Instruments LM2651MTC-1.8/NOPB
- Part No.:
- LM2651MTC-1.8/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM2651MTC-1.8/NOPB.pdf
- Description:
- IC REG BUCK 1.8V 1.5A 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,210
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Product details
Overview
LM2651MTC-1.8/NOPB from Texas Instruments is a 1.5-A synchronous step-down DC-DC switching regulator with fixed 1.8-V output, 4–14-V input range, 300-kHz fixed-frequency PWM operation, and patented current-mode control. It delivers up to 97% efficiency across 1.5-A to 15-mA load range and integrates low-RDS(on) MOSFETs (75 mΩ high-side) for compact battery-powered power supplies.
For engineers reviewing the LM2651MTC-1.8/NOPB datasheet, LM2651MTC-1.8/NOPB pinout, LM2651MTC-1.8/NOPB application, or LM2651MTC-1.8/NOPB equivalent, key selection considerations include its ultrahigh light-load efficiency, internal current sensing eliminating external sense resistors, 7-µA shutdown current, programmable soft-start, and thermal/UVLO/current-limit protection in a 16-pin TSSOP package.
Technical Context
The LM2651MTC-1.8/NOPB operates in constant-frequency current-mode PWM under moderate-to-heavy loads and automatically transitions to hysteretic mode at light loads (below ~100 mA) to sustain >80% efficiency down to 15 mA. Its patented internal current-sensing circuit replaces the external sense resistor, improving noise immunity and reducing BOM count.
It features a 300-kHz oscillator enabling small external magnetics, integrated high- and low-side MOSFETs with 75 mΩ RDS(on), bootstrap gate drive (6.7 V typical), and dual ground pins (AGND and PGND) for analog/digital separation. Protection includes input UVLO (3.85 V rising threshold), cycle-by-cycle current limit (~2 A), thermal shutdown (165°C), and soft-start via external capacitor on SD(SS) pin.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output voltage | Fixed 1.8 V ±2% over full temperature and load range - ensures stable core supply for low-voltage microcontrollers and FPGAs. |
| Input voltage range | 4 V to 14 V - supports single-cell LiFePO₄, dual-cell alkaline/NiMH, or 5–12 V industrial rails without pre-regulation. |
| Max output current | 1.5 A continuous - sufficient for powering SoCs, DSPs, or multiple peripherals from a single buck stage. |
| Switching frequency | 300 kHz (±10%) - enables use of sub-10-mm inductors and reduces EMI compared to 1–2 MHz alternatives. |
| Quiescent current | 1.6 mA typical - minimizes standby drain in always-on systems like IoT sensors or remote controls. |
| Shutdown current | 7 µA maximum - extends shelf life and battery runtime during deep sleep or system off states. |
| Efficiency peak | 97% at mid-load - reduces thermal stress and eliminates need for heatsinking in space-constrained designs. |
| Thermal shutdown | 165°C with 25°C hysteresis - provides robust fault recovery without latch-up or manual reset. |
Pinout & Package
LM2651MTC-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 functions are validated per TI SNVS032E Rev E datasheet.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2 SW | Switched-node output | Connects to source of internal high-side MOSFET and inductor - carries high di/dt; requires short, low-inductance routing. |
| 3–5 VIN | Main power input | Accepts 4–14 V input; multiple pins reduce IR drop and improve thermal dissipation for 1.5-A operation. |
| 6 VCB | Bootstrap capacitor node | Supplies gate drive voltage for high-side MOSFET; requires 0.1-µF ceramic capacitor to SW and AGND. |
| 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 ramp time - enables controlled power sequencing. |
| 9 FB | Feedback input | Monitors regulated 1.8-V output directly - no external divider needed for fixed-output version. |
| 10 COMP | Compensation network | Connects to error amplifier output; external RC network stabilizes loop response and ensures ≥45° phase margin. |
| 11 NC | No connection | Unbonded die pad - must remain floating; no PCB trace or copper pour should connect to this pin. |
| 12, 13 AGND | Analog ground reference | Return path for feedback, compensation, and control circuits - isolated from power ground to prevent noise injection. |
| 14–16 PGND | Power ground return | High-current return for MOSFETs and inductor - routed with wide copper to minimize voltage bounce and EMI. |
Key Features
| Feature | Design Value |
|---|---|
| Ultrahigh efficiency up to 97% | Reduces thermal load and enables fanless operation in sealed enclosures or handheld devices. |
| Patented internal current sensing | Eliminates external sense resistor - saves board area, cost, and avoids accuracy drift due to temperature or layout parasitics. |
| Synchronous rectification | Replaces Schottky catch diode with low-RDS(on) MOSFET - cuts conduction loss by >50% vs asynchronous designs. |
| Adjustable soft-start | Prevents inrush current surges during power-up - protects input capacitors and upstream regulators in multi-rail systems. |
| Light-load hysteretic mode | Maintains >80% efficiency at 15 mA - extends battery life in standby without requiring external enable control. |
| Integrated protection suite | Includes UVLO, thermal shutdown, and cycle-by-cycle current limiting - enables robust operation without external supervision ICs. |
Applications
| Personal Digital Assistants (PDAs) | Computer Peripherals |
|---|---|
|
Use Scenario: Powering ARM-based application processors and DDR memory in legacy PDA platforms with single Li-ion cell input. IC Role / Device Role / Timing Role: Primary 1.8-V core regulator delivering clean, tightly regulated voltage with fast transient response to processor load steps. Use Value: 97% peak efficiency and 7-µA shutdown current extend usable runtime between charges by >25% versus older linear or asynchronous buck solutions. |
Use Scenario: Supplying 1.8-V I/O banks for USB 2.0 hubs, card readers, or docking stations powered from 5-V USB or wall adapters. IC Role / Device Role / Timing Role: High-efficiency point-of-load converter replacing LDOs to reduce heat generation in thermally constrained plastic enclosures. Use Value: Synchronous architecture and 300-kHz switching allow use of 4.7-µH inductors < 3 mm tall - enabling ultra-thin peripheral designs. |
| Battery-Powered Devices | Handheld Scanners |
|
Use Scenario: Providing regulated 1.8-V supply for Bluetooth LE SoCs and sensors in portable medical monitors or asset trackers. IC Role / Device Role / Timing Role: Always-on power management IC maintaining regulation during intermittent wake/sleep cycles with minimal quiescent draw. Use Value: Hysteretic light-load mode sustains >85% efficiency at 20 mA - doubling battery life versus fixed-frequency-only converters in duty-cycled applications. |
Use Scenario: Powering CMOS image sensors and laser drivers in ruggedized barcode scanners operating from 2×AA or Li-ion packs. IC Role / Device Role / Timing Role: Main DC-DC regulator handling wide input variation (4–14 V) while delivering stable 1.8-V rail for precision analog front-ends. Use Value: Input UVLO (3.85 V) and thermal shutdown (165°C) ensure safe operation during battery depletion or extended use in hot environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS54302DDCR | 3-A rating, 2.5–6-V input, 1.5-MHz switching, integrated compensation - higher current but narrower input range. | Preferred for newer designs needing higher output current or smaller inductors; not suitable for 12-V input or 1.5-A+ loads at 14-V input. | Select when board space is critical and input is limited to 5–6 V; verify thermal performance at full load with 1.5-MHz switching. |
| LM2678SD-1.8/NOPB | 2.5-A rating, 8–40-V input, 63-kHz frequency, external MOSFETs - wider input but lower efficiency and larger magnetics. | Used in industrial 24-V systems where input exceeds 14 V; lacks integrated MOSFETs and requires more external components. | Choose only if input voltage exceeds 14 V or output current demand exceeds 1.5 A; expect 5–10% lower efficiency and larger solution size. |
Compared with LM2651MTC-1.8/NOPB, TPS54302DDCR offers higher current and frequency but sacrifices 12-V compatibility, while LM2678SD-1.8/NOPB supports higher input voltages but requires external FETs and delivers lower efficiency - making LM2651MTC-1.8/NOPB optimal for 4–14-V, 1.5-A, space-constrained battery applications.
Availability
LM2651MTC-1.8/NOPB is available at Aetrix Electronics and suitable for personal digital assistants, computer peripherals, and battery-powered devices requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for LM2651MTC-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 designing analog ICs, embedded processors, and connectivity solutions for industrial, automotive, and consumer markets since 1930.
The LM2651 series was developed as a high-efficiency, integrated synchronous buck regulator family targeting portable and battery-operated equipment needing minimal external components and ultra-low quiescent current.
FAQ
What is the recommended input capacitor for LM2651MTC-1.8/NOPB?
A low-ESR ceramic or tantalum capacitor (≥10 µF, 25-V rating) placed between VIN and PGND is required. TI recommends adding a 0.1-µF ceramic capacitor close to the VIN and PGND pins to suppress high-frequency noise. RMS current rating must exceed IOUT/2, especially when input voltage approaches twice the output voltage.
Does LM2651MTC-1.8/NOPB require an external Schottky diode?
Yes - TI recommends an external Schottky diode (e.g., RB050M-30) across the low-side MOSFET to prevent reverse-recovery losses during dead time. This improves efficiency by 1–2%, especially at high input voltages and loads, and reduces EMI caused by body-diode conduction.
How does the soft-start function work on LM2651MTC-1.8/NOPB?
The LM2651MTC-1.8/NOPB uses an internal 11-µA current source to charge an external capacitor on the SD(SS) pin. Soft-start time is calculated as TSS = CSS × 0.6 V / 2 µA + CSS × (2 V − 0.6 V) / 10 µA. A 100-nF capacitor yields ~12-ms startup with controlled current ramp and no output overshoot.
What is the thermal performance of LM2651MTC-1.8/NOPB in TSSOP package?
LM2651MTC-1.8/NOPB has a junction-to-ambient thermal resistance (RθJA) of 97.3°C/W in the 16-pin TSSOP package. With 1.5-A load and 10-V input, typical power dissipation is ~0.45 W, resulting in ~44°C junction rise above ambient - well within the 125°C max operating limit. Adding 2 cm² copper pour reduces RθJA by ~25°C/W.
Can LM2651MTC-1.8/NOPB be used with input voltage below 4 V?
No - the absolute minimum recommended input voltage is 4 V per datasheet Section 6.3. Below this, undervoltage lockout (UVLO) prevents operation. The UVLO rising threshold is 3.85 V with 210-mV hysteresis, so the part will not start until VIN exceeds 3.85 V and remains active down to 3.64 V before shutting off.
LM2651MTC-1.8/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- 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
LM2651MTC-1.8/NOPB FAQ
1.How can I place an order for LM2651MTC-1.8/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2651MTC-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 LM2651MTC-1.8/NOPB reliable?
The price and inventory of LM2651MTC-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 LM2651MTC-1.8/NOPB is usually 5 days.
3.What payment methods are accepted for LM2651MTC-1.8/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2651MTC-1.8/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2651MTC-1.8/NOPB?
LM2651MTC-1.8/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2651MTC-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 LM2651MTC-1.8/NOPB?
For technical support, including LM2651MTC-1.8/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2651MTC-1.8/NOPB requirements.
6.How does Aetrix verify that LM2651MTC-1.8/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2651MTC-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 LM2651MTC-1.8/NOPB meets industry standards.
7.What is the process for return or replacement of LM2651MTC-1.8/NOPB?
All LM2651MTC-1.8/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2651MTC-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 LM2651MTC-1.8/NOPB part is unused and in its original packaging.
Return procedure for LM2651MTC-1.8/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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