My Inquiry
My Account
Texas Instruments LM2655MTCX-ADJ
- Part No.:
- LM2655MTCX-ADJ
- Manufacturer:
- Texas Instruments
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM2655MTCX-ADJ.pdf
- Description:
- IC REG BUCK ADJ 2.5A 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,782
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LM2655MTCX-ADJ from Texas Instruments (formerly National Semiconductor) is a 2.5A synchronous step-down DC-DC regulator with internal high-side MOSFET (RDS(ON) = 33 mΩ), fixed 300 kHz PWM switching, and adjustable output voltage via external feedback resistors. It supports 4–14 V input, delivers >90% efficiency in synchronous mode, and integrates programmable soft-start, input undervoltage lockout, and thermal shutdown - ideal for portable TFT monitors and battery-powered peripherals.
For engineers reviewing the LM2655MTCX-ADJ datasheet, LM2655MTCX-ADJ pinout, LM2655MTCX-ADJ application, or LM2655MTCX-ADJ equivalent, key selection considerations include its TSSOP-16 package footprint, synchronous/async mode flexibility, 1.238 V feedback reference, low 12 µA shutdown current, and integrated current-sense architecture eliminating external sense resistors.
Technical Context
The LM2655MTCX-ADJ implements constant-frequency current-mode control with a patented internal current-sensing circuit that eliminates the need for an external sense resistor. Its 300 kHz oscillator enables compact magnetics while maintaining stable regulation across 4–14 V input and load currents up to 2.5 A.
It operates in either synchronous mode (using external low-side N-MOSFET driven by LDR pin) or asynchronous mode (with external Schottky diode), offering design trade-offs between peak efficiency (>96%) and BOM cost. Protection features include input UVLO (3.8 V threshold), output overvoltage (108% VOUT) and undervoltage latch (81% VOUT), and thermal shutdown at 165 °C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4 V to 14 V - supports wide-input industrial and portable power rails without pre-regulation. |
| Output Current | 2.5 A continuous - sufficient for powering core logic in HDDs, peripherals, and TFT panel supplies. |
| Switching Frequency | 300 kHz fixed - enables use of small, low-cost inductors and simplifies EMI filtering design. |
| Feedback Reference | 1.238 V ±30 mV - sets precise output voltage via external resistor divider; enables 1.24–13 V adjustment range. |
| High-Side RDS(ON) | 33 mΩ typical - reduces conduction loss and improves full-load efficiency in compact TSSOP-16 layout. |
| Shutdown Current | <12 µA - extends battery life in always-on or standby modes of portable devices. |
| Thermal Shutdown | 165 °C with 25 °C hysteresis - provides robust protection during overload or poor heatsinking conditions. |
Pinout & Package
LM2655MTCX-ADJ is housed in a 16-pin TSSOP (Thin Shrink Small Outline Package) with exposed thermal pad (NS package code MTC16), optimized for high-power density and thermal performance on standard PCBs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1–2, SW | Switched-node connection | Drain of internal high-side MOSFET; connects to inductor and external Schottky diode or low-side MOSFET source. |
| 3–5, 14–16, PVIN | Main power supply input | Drain connection for internal high-side MOSFET; multiple pins reduce trace resistance and improve current handling. |
| 6, VCB | Bootstrap capacitor node | Provides gate drive voltage for internal high-side N-MOSFET; requires 0.1 µF ceramic capacitor to SW. |
| 7, AVIN | Analog supply input | Powers control circuitry independently; allows extended input operation when decoupled from PVIN. |
| 8, SD(SS) | Shutdown / Soft-start control | Pulling <0.3 V disables regulator; capacitor to GND controls startup ramp and sequencing. |
| 9, FB | Feedback input | Monitors output voltage via resistor divider; 1.238 V reference enables precise adjustable regulation. |
| 10, COMP | Compensation network | Connects error amplifier output to external RC network for loop stability tuning. |
| 11, LDELAY | Undervoltage latch delay | Capacitor to GND sets timeout before UVLO latch triggers (5 µA charge current, 2 V threshold). |
| 12, LDR | Low-side driver output | Drives external N-MOSFET gate in synchronous mode; 500 mA sink / 180 mA source capability. |
| 13, GND | Power ground | Common return for power and control circuits; must be low-impedance and thermally connected to pad. |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous/Asynchronous Mode Flexibility | Single IC supports both topologies: synchronous for >96% efficiency or asynchronous for lower BOM cost using Schottky diode. |
| Integrated Current Sensing | Patented internal sensing eliminates external current-sense resistor - reduces cost, board area, and noise susceptibility. |
| Programmable Soft-Start | Capacitor-controlled ramp on SD(SS) pin limits inrush current and enables controlled power-up sequencing of multiple rails. |
| Comprehensive Protection Suite | Includes input UVLO, output OVP/UVP latch, thermal shutdown, and cycle-by-cycle current limiting - ensures robust field operation. |
| Wide Input Range with Dual VIN Pins | Separate PVIN (power path) and AVIN (control supply) allow operation with input voltages as low as ~4.5 V on PVIN when AVIN is externally biased. |
Applications
| TFT Monitor Power Supply | Hard Disk Drive (HDD) Logic Rail |
|---|---|
|
Use Scenario: Powers digital timing controller (TCON) and source/gate drivers in 12–24 V input TFT-LCD panels. IC Role / Device Role / Timing Role: Primary 3.3 V or 5 V buck regulator delivering stable, low-noise power under dynamic backlight and video load transients. Use Value: High efficiency (>90%) minimizes heat buildup in sealed display enclosures; programmable soft-start prevents display initialization glitches. |
Use Scenario: Supplies 3.3 V logic and servo control circuits in 2.5" and 3.5" SATA/IDE hard drives. IC Role / Device Role / Timing Role: Main system regulator converting 5 V or 12 V bus to regulated 3.3 V for microcontroller, interface ICs, and actuator drivers. Use Value: Low 12 µA shutdown current extends idle battery life; thermal shutdown protects against enclosure overheating during sustained seek operations. |
| Internet Appliance Core Rail | Portable Peripheral Power |
|
Use Scenario: Provides 1.8 V or 2.5 V core voltage for ARM-based networking gateways, VoIP phones, and set-top boxes. IC Role / Device Role / Timing Role: Adjustable-output buck converter supporting multiple SoC voltage requirements via feedback resistor reconfiguration. Use Value: 1.238 V reference and wide 1.24–13 V output range enable single-design reuse across product variants; TSSOP-16 footprint fits space-constrained layouts. |
Use Scenario: Powers USB hubs, card readers, and docking stations operating from 5 V USB or 12 V wall adapters. IC Role / Device Role / Timing Role: High-current, low-quiescent regulator delivering 3.3 V or 5 V with fast transient response to plug-in events. Use Value: Synchronous mode achieves >95% efficiency at 2 A, reducing thermal stress in plastic enclosures; LDR pin enables seamless integration with discrete low-side FETs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS54260DGQR | Wider 3.5–60 V input, integrated low-side FET, 2.5 A rating, but no LDR pin - fully integrated vs. LM2655MTCX-ADJ's external low-side drive. | Better suited for high-input industrial systems; less flexible for custom low-side MOSFET selection or async diode use. | Choose TPS54260DGQR when input exceeds 14 V or board space is critical; retain LM2655MTCX-ADJ for topology flexibility and proven thermal performance in TSSOP-16. |
| LM2678SD-ADJ/NOPB | 5 A rating, 8-pin SOIC, no LDR pin, fixed 260 kHz frequency, higher RDS(ON) (75 mΩ), no programmable UVLO delay. | Higher current capacity but larger solution size and reduced efficiency at light loads due to lack of synchronous option. | Choose LM2678SD-ADJ/NOPB only if 5 A output is required and synchronous efficiency is not critical; LM2655MTCX-ADJ offers superior power density and thermal management. |
Compared with TPS54260DGQR and LM2678SD-ADJ/NOPB, the LM2655MTCX-ADJ uniquely balances adjustability, synchronous/async dual-mode operation, and compact TSSOP-16 packaging - making it optimal for mid-power portable and embedded applications where layout flexibility and thermal control are prioritized over ultra-wide input range or highest possible current rating.
Availability
LM2655MTCX-ADJ is available at Aetrix Electronics and suitable for TFT monitor power supplies, hard disk drive logic rails, and internet appliance core voltage regulation requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.
Supply support for LM2655MTCX-ADJ 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 acquired National Semiconductor in 2011 and maintains full technical and manufacturing continuity for legacy power management products including the LM2655 series.
The LM2655MTCX-ADJ belongs to TI's high-efficiency synchronous buck regulator product line, designed specifically for space-constrained portable and embedded systems needing flexible, reliable, and thermally efficient DC-DC conversion.
FAQ
What is the feedback reference voltage of the LM2655MTCX-ADJ?
The LM2655MTCX-ADJ uses a precision 1.238 V feedback reference voltage (VFB) with ±30 mV tolerance over temperature. This value is used in the resistor divider equation (RFB1 = RFB2 × (VOUT − 1.238)/1.238) to set the output voltage. The LM2655MTCX-ADJ's tight reference tolerance enables accurate regulation across its 1.24–13 V adjustable range.
Can the LM2655MTCX-ADJ operate in synchronous mode without an external MOSFET?
No - the LM2655MTCX-ADJ requires an external low-side N-channel MOSFET to operate in synchronous mode. Its LDR pin provides gate drive capability (500 mA sink / 180 mA source), but the low-side switch itself is not integrated. The LM2655MTCX-ADJ's architecture intentionally separates this function to allow optimization of MOSFET selection for specific voltage, current, and thermal requirements.
What is the minimum recommended input voltage for reliable startup of the LM2655MTCX-ADJ?
The LM2655MTCX-ADJ has a guaranteed input undervoltage lockout (UVLO) rising threshold of 3.8 V, with hysteresis of 210 mV. For reliable startup, the input voltage on PVIN must exceed 3.95 V (maximum specified UVLO threshold). Additionally, AVIN must be ≥4.0 V to power control circuitry - so dual-supply biasing may be needed for inputs below 4 V.
How does the LM2655MTCX-ADJ achieve current sensing without an external resistor?
The LM2655MTCX-ADJ uses patented internal current-sensing circuitry that monitors the voltage drop across its integrated high-side MOSFET's RDS(ON). This eliminates the need for an external sense resistor, reducing BOM cost, PCB area, and power loss. The sensed signal feeds directly into the current-mode PWM comparator, enabling accurate cycle-by-cycle current limiting in the LM2655MTCX-ADJ.
What thermal considerations apply to the LM2655MTCX-ADJ in TSSOP-16 package?
The LM2655MTCX-ADJ in TSSOP-16 has a θJA of 140 °C/W under worst-case conditions (no heatsink). With 893 mW max power dissipation at 25 °C ambient, derating is required above 25 °C (−7.14 mW/°C). Thermal shutdown activates at 165 °C with 25 °C hysteresis. To maintain reliability, the LM2655MTCX-ADJ requires adequate copper pour and vias under its exposed thermal pad per NS MTC16 layout guidelines.
LM2655MTCX-ADJ 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:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4V
- Voltage - Input (Max):
- 14V
- Voltage - Output (Min/Fixed):
- 1.238V
- Voltage - Output (Max):
- 13V
- Current - Output:
- 2.5A
- Frequency - Switching:
- 300kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-TSSOP
LM2655MTCX-ADJ FAQ
1.How can I place an order for LM2655MTCX-ADJ through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2655MTCX-ADJ 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 LM2655MTCX-ADJ reliable?
The price and inventory of LM2655MTCX-ADJ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2655MTCX-ADJ is usually 5 days.
3.What payment methods are accepted for LM2655MTCX-ADJ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2655MTCX-ADJ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2655MTCX-ADJ?
LM2655MTCX-ADJ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2655MTCX-ADJ 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 LM2655MTCX-ADJ?
For technical support, including LM2655MTCX-ADJ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2655MTCX-ADJ requirements.
6.How does Aetrix verify that LM2655MTCX-ADJ is sourced from the original manufacturer or authorized distributors?
All LM2655MTCX-ADJ 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 LM2655MTCX-ADJ meets industry standards.
7.What is the process for return or replacement of LM2655MTCX-ADJ?
All LM2655MTCX-ADJ units undergo pre-shipment inspection (PSI). If there is an issue with LM2655MTCX-ADJ, 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 LM2655MTCX-ADJ part is unused and in its original packaging.
Return procedure for LM2655MTCX-ADJ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM2655MTCX-ADJ Tags
-
TPS562201DDCR
Texas Instruments
-
MC34063ABD-TR
STMicroelectronics
-
TPS561201DDCR
Texas Instruments
-
MC33063ADR
Texas Instruments
-
MC34063ADR
Texas Instruments
-
TPS560200DBVR
Texas Instruments
-
AP3012KTR-G1
Diodes Incorporated
-
TLV61048DBVR
Texas Instruments
-
AZ34063UMTR-G1
Diodes Incorporated
-
TPS562200DDCR
Texas Instruments
-
AP62300TWU-7
Diodes Incorporated
-
MC34063EBD-TR
STMicroelectronics
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
