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Texas Instruments LM2655MTC-3.3
- Part No.:
- LM2655MTC-3.3
- Manufacturer:
- Texas Instruments
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM2655MTC-3.3.pdf
- Description:
- IC REG BUCK 3.3V 2.5A 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,308
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Product details
Overview
LM2655MTC-3.3 from Texas Instruments (formerly National Semiconductor) is a 2.5A synchronous step-down DC-DC regulator in TSSOP-16 package, featuring internal 33 mΩ high-side MOSFET, fixed 300 kHz PWM switching, and factory-trimmed 3.3 V output. It supports both synchronous and asynchronous operation, delivers >90% efficiency at 5 V input, and integrates programmable soft-start, input undervoltage lockout, and thermal shutdown - ideal for TFT monitor power rails and portable peripheral supplies.
For engineers reviewing the LM2655MTC-3.3 datasheet, LM2655MTC-3.3 pinout, LM2655MTC-3.3 application, or LM2655MTC-3.3 equivalent, key selection criteria include verified 3.3 V ±2.4% output accuracy over load/temperature, guaranteed <12 µA shutdown current, synchronous low-side drive capability (LDR pin), and TSSOP-16 thermal performance with θJA = 140 °C/W.
Technical Context
The LM2655MTC-3.3 implements constant-frequency current-mode control using patented resistorless current sensing, eliminating external sense resistors while maintaining cycle-by-cycle peak current limiting. Its architecture separates PVIN (power input) and AVIN (analog supply) rails, enabling extended input range configurations where PVIN can be as low as ~3.8 V when AVIN is independently powered.
It provides dual protection modes: output undervoltage latch (enabled after configurable delay via LDELAY pin) and immediate overvoltage shutdown at 108–114% of nominal output. The integrated low-side driver (LDR) delivers 500 mA sink / 180 mA source with 7 ns fall time, supporting fast-switching N-channel MOSFETs with Ciss < 1000 pF to meet 30 ns deadtime requirements.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3 V ±2.4% (3.235–3.416 V) across full temperature and 100 mA–2.5 A load range |
| Input Voltage Range | 4.0 V to 14.0 V on AVIN; PVIN supports ≥3.8 V with external bias - enables flexible rail sequencing |
| Switching Frequency | Fixed 300 kHz (255–345 kHz over temp); enables compact magnetics and predictable EMI filtering |
| Internal High-Side RDS(ON) | 33 mΩ typical (80 mΩ max); reduces conduction loss and improves full-load efficiency vs. external FET solutions |
| Shutdown Current | <12 µA max at TJ = 125 °C; ensures battery-powered systems retain >99.9% standby energy |
| Thermal Shutdown | 165 °C with 25 °C hysteresis; prevents permanent damage during sustained overload or poor heatsinking |
| Soft-Start Time | Programmable via SS pin capacitor; controls inrush current and enables controlled power-up sequencing |
Pinout & Package
LM2655MTC-3.3 is housed in a 16-pin TSSOP (Thin Shrink Small Outline Package) with exposed thermal pad (NS package code MTC16), optimized for surface-mount assembly and moderate-power thermal dissipation (PD = 893 mW at TA = 25 °C).
| 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 FET |
| 3–5, 14–16, PVIN | Main power input | High-current path to drain of internal high-side MOSFET; multiple pins reduce trace resistance and improve thermal spreading |
| 6, VCB | Bootstrap capacitor connection | 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 only; must be 4–14 V; enables extended PVIN operation below 4 V when biased separately |
| 8, SD(SS) | Shutdown & soft-start control | Pulling <0.3 V disables regulator; capacitor to GND sets soft-start ramp and prevents inrush current surges |
| 9, FB | Feedback input | Monitors regulated 3.3 V output directly; no external divider required for fixed-output version |
| 10, COMP | Compensation network | Connects external RC network to stabilize loop response; supports Type II compensation |
| 11, LDELAY | Undervoltage latch delay | 5 µA current source charges external capacitor; sets timeout before UVLO latch triggers (TDELAY = CDELAY × 400 ms/nF) |
| 12, LDR | Low-side driver output | Drives external N-MOSFET gate in synchronous mode; 500 mA sink capability ensures <30 ns turn-off |
| 13, GND | Power ground | Common return for PVIN, SW, and LDR; must be low-impedance plane tied to thermal pad |
Key Features
| Feature | Design Value |
|---|---|
| Resistorless current sensing | Eliminates external sense resistor, reducing BOM cost, PCB area, and I²R losses while improving noise immunity |
| Synchronous/asynchronous mode select | Configurable via LDR pin termination - enables trade-off between peak efficiency (>96%) and solution cost |
| Programmable soft-start | Capacitor-controlled ramp limits inrush current and allows precise sequencing of multiple rails in multi-voltage systems |
| Independent PVIN/AVIN rails | Permits ultra-low input operation (e.g., 3.8 V PVIN) when AVIN is supplied from stable 5 V or 12 V auxiliary rail |
| Comprehensive protection suite | Includes input UVLO (3.8 V threshold), output UV/OV latch, thermal shutdown, and cycle-by-cycle current limit |
Applications
| TFT Monitor Power Supply | Hard Disk Drive +5 V Rail |
|---|---|
|
Use Scenario: Provides stable 3.3 V logic supply and 5 V analog rail for LCD timing controllers and source drivers in 15–24 inch TFT panels. IC Role / Device Role / Timing Role: Primary buck regulator delivering 2.5 A continuous current with tight line/load regulation (<1.7% max deviation). Use Value: Fixed 3.3 V output eliminates feedback resistor errors; TSSOP-16 footprint fits dense display PCB layouts without requiring external current sense components. |
Use Scenario: Generates clean +5 V from 12 V or 19 V adapter input for HDD spindle motor control ICs and interface logic. IC Role / Device Role / Timing Role: Synchronous buck converter operating at 300 kHz to minimize EMI near sensitive read/write channels. Use Value: Internal 33 mΩ MOSFET and low-quiescent-current design (<3 mA active, <12 µA shutdown) extend battery life in portable storage devices. |
| Internet Appliance CPU Core Supply | USB Peripheral Hub Power |
|
Use Scenario: Powers ARM-based SoC cores (e.g., TI AM335x) in network-attached storage or VoIP gateways requiring 3.3 V @ 2 A. IC Role / Device Role / Timing Role: High-efficiency step-down regulator with programmable soft-start to prevent brownout during cold boot. Use Value: Patented current sensing ensures accurate current limiting across temperature; LDELAY pin enables graceful recovery from transient overloads. |
Use Scenario: Supplies regulated 3.3 V to USB 2.0 hub controllers and PHYs in docking stations and multi-port adapters. IC Role / Device Role / Timing Role: Compact TSSOP-16 solution meeting USB power delivery specs with <2.4% output tolerance and fast transient response. Use Value: Low-side driver (LDR) supports optional synchronous FET for >94% efficiency at 500 mA–2 A loads, reducing thermal stress in enclosed enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS54231DR | Fixed 3.3 V, 2 A, 570 kHz, integrated high/low-side FETs; no external LDR or PVIN/AVIN separation | Higher frequency enables smaller inductors; lacks programmable LDELAY and independent PVIN biasing | Choose for space-constrained designs needing single-chip simplicity; avoid if extended low-VIN operation or sequenced UVLO is required |
| LM2678-3.3 | 3 A, 260 kHz, external diode only (asynchronous), no LDR or LDELAY; higher RDS(ON) (75 mΩ) | No synchronous option; lower efficiency (~85% at 2 A); simpler protection set (no output UV/OV latch) | Choose for cost-sensitive, non-battery applications where 90%+ efficiency and advanced sequencing are not critical |
Compared with LM2655MTC-3.3, TPS54231DR offers higher integration but sacrifices design flexibility in input range and protection configurability, while LM2678-3.3 provides robustness at lower cost but cannot match the 96% peak efficiency or programmable fault timing of the LM2655MTC-3.3.
Availability
LM2655MTC-3.3 is available at Aetrix Electronics and suitable for TFT monitors, hard disk drives, and internet appliances requiring stable component supply, long-term industrial lifecycle support, and consistent parametric performance across manufacturing lots.
Supply support for LM2655MTC-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 acquired National Semiconductor in 2011 and maintains full technical and manufacturing continuity for legacy power management products including the LM2655 series.
The LM2655 product line was designed for high-density, medium-power DC-DC conversion in space-constrained consumer and computing applications - emphasizing efficiency, protection flexibility, and ease of layout with minimal external components.
FAQ
What is the output voltage tolerance of the LM2655MTC-3.3 over temperature and load?
The LM2655MTC-3.3 delivers a factory-trimmed 3.3 V output with guaranteed tolerance of ±2.4% (3.235 V to 3.416 V) across −40 °C to +125 °C junction temperature and 100 mA to 2.5 A load range. This specification is validated per the LM2655-3.3 Electrical Characteristics table in the official datasheet (DS101284), with worst-case limits applying over full operating conditions - ensuring reliable logic-level compatibility in TFT monitors and peripheral interfaces.
Can the LM2655MTC-3.3 operate with input voltage below 4 V?
Yes - the LM2655MTC-3.3 supports extended low-input operation by separating PVIN (power input) and AVIN (analog supply) functions. When AVIN is supplied with a stable 4–14 V bias (e.g., from a separate LDO), PVIN may be as low as 3.8 V, enabling use in battery-powered systems nearing end-of-discharge. This configuration is explicitly detailed in the "Extending Input Voltage Range" application circuit (Figure 4, DS101284) and does not require modification of the LM2655MTC-3.3 itself.
Does the LM2655MTC-3.3 require an external current-sense resistor?
No - the LM2655MTC-3.3 uses patented internal current-sensing circuitry that monitors high-side MOSFET conduction without an external sense resistor. This eliminates associated power loss, board space, and noise coupling while maintaining accurate cycle-by-cycle current limiting. The feature is confirmed in the General Description and Operation sections of the LM2655 datasheet (DS101284), and applies identically to the LM2655MTC-3.3 fixed-output variant.
How is synchronous versus asynchronous operation selected on the LM2655MTC-3.3?
Synchronous operation is enabled by connecting the LDR pin to the gate of an external N-channel MOSFET; asynchronous mode is selected by leaving LDR open or terminating it with a >1 MΩ resistor. The LM2655MTC-3.3's internal logic automatically adapts - driving LDR in sync mode or disabling it in async mode. This dual-mode capability is intrinsic to the LM2655MTC-3.3 silicon and requires no configuration bits or external programming.
What protection features are integrated into the LM2655MTC-3.3?
The LM2655MTC-3.3 integrates six hardware protections: (1) input undervoltage lockout (3.8 V threshold), (2) output overvoltage shutdown (108–114% of 3.3 V), (3) output undervoltage latch with user-configurable delay (via LDELAY pin), (4) thermal shutdown (165 °C), (5) cycle-by-cycle current limiting, and (6) soft-start inrush control. All are active without external components and documented in the Absolute Maximum Ratings and Electrical Characteristics tables of DS101284 for the LM2655MTC-3.3.
LM2655MTC-3.3 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):
- 3.3V
- Voltage - Output (Max):
- -
- 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
LM2655MTC-3.3 FAQ
1.How can I place an order for LM2655MTC-3.3 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2655MTC-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 LM2655MTC-3.3 reliable?
The price and inventory of LM2655MTC-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 LM2655MTC-3.3 is usually 5 days.
3.What payment methods are accepted for LM2655MTC-3.3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2655MTC-3.3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2655MTC-3.3?
LM2655MTC-3.3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2655MTC-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 LM2655MTC-3.3?
For technical support, including LM2655MTC-3.3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2655MTC-3.3 requirements.
6.How does Aetrix verify that LM2655MTC-3.3 is sourced from the original manufacturer or authorized distributors?
All LM2655MTC-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 LM2655MTC-3.3 meets industry standards.
7.What is the process for return or replacement of LM2655MTC-3.3?
All LM2655MTC-3.3 units undergo pre-shipment inspection (PSI). If there is an issue with LM2655MTC-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 LM2655MTC-3.3 part is unused and in its original packaging.
Return procedure for LM2655MTC-3.3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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