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Texas Instruments LM3677LEX-1.5/NOPB
- Part No.:
- LM3677LEX-1.5/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 6-UFDFN
- Datasheet:
-
LM3677LEX-1.5/NOPB.pdf
- Description:
- IC REG BUCK 1.5V 600MA 6USON
- Quantity:
- Payment:
- Shipping:
Inventory:4,656
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Product details
Overview
LM3677LEX-1.5/NOPB from Texas Instruments is a 3 MHz, 600 mA synchronous step-down DC-DC converter optimized for ultra-low-voltage circuits powered by a single Li-Ion cell (2.7V–5.5V input), delivering a fixed 1.5 V output with ±2.5% regulation accuracy, 16 µA typical quiescent current in PFM mode, and internal PFET/NFET synchronous rectification. It serves as the primary core voltage regulator in mobile phone baseband processors and camera modules.
For engineers reviewing the LM3677LEX-1.5/NOPB datasheet, LM3677LEX-1.5/NOPB pinout, LM3677LEX-1.5/NOPB application, or LM3677LEX-1.5/NOPB equivalent, key selection criteria include its 5-bump DSBGA package footprint, automatic PFM/PWM mode transition at ~42 mA (VIN = 3.6 V), 0.01 µA shutdown current, and requirement for only three external passive components (1.0 µH inductor, 4.7 µF CIN, 10 µF COUT).
Technical Context
The LM3677LEX-1.5/NOPB implements a voltage-mode PWM controller with input voltage feed-forward compensation to maintain stable line regulation across its 2.7V–5.5V input range. Its internal 0.5 V reference and fixed 1.5 V output are achieved via resistorless feedback - the device is factory-trimmed and does not require external resistors on the FB pin.
It integrates dual power switches: a PFET with 350 mΩ typical RDS(ON) and an NFET with 150 mΩ typical RDS(ON), enabling >90% efficiency at 300 mA load and 3.6 V input. Thermal shutdown activates at 150°C (typ.), and cycle-by-cycle current limiting trips at 1220 mA (typ.) to protect against overload.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 1.5 V ±2.5% - eliminates need for external feedback resistors and simplifies layout for space-constrained portable designs. |
| Max Output Current | 600 mA - supports core logic rails of ARM-based application processors and image signal processors without external boost stages. |
| Switching Frequency | 3 MHz (typ.), 2.5–3.5 MHz (min–max) - enables use of sub-1.0 mm height, 1.0 µH shielded inductors and reduces EMI filtering burden. |
| Quiescent Current | 16 µA (typ.) in PFM mode - extends battery runtime during display-off or standby states in handheld devices. |
| Shutdown Current | 0.01 µA (typ.) - ensures negligible battery drain when system is fully powered down via EN pin control. |
| Input Voltage Range | 2.7 V to 5.5 V - compatible with single-cell Li-Ion (fully charged to 4.2 V, discharged to 2.7 V) and regulated 3.3 V/5 V rails. |
| Feedback Reference | 0.5 V internal - sets output as VOUT = 0.5 V × (1 + R1/R2); for fixed 1.5 V version, R1/R2 ratio is laser-trimmed internally. |
Pinout & Package
LM3677LEX-1.5/NOPB is housed in a lead-free, RoHS-compliant 5-bump DSBGA package (package code YZR0005), measuring 1.0 mm × 1.0 mm × 0.5 mm, with 0.4 mm pitch and bottom-side thermal pad for enhanced thermal dissipation in thin-profile mobile PCBs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (A1) | Power input | Connects directly to 4.7 µF input capacitor; must be decoupled within 2 mm to minimize high-frequency switching noise injection into the battery rail. |
| GND (A3) | Ground reference | Primary return path for PFET/NFET switching currents; requires low-inductance connection to thermal pad and system ground plane. |
| EN (C1) | Enable control | Logic-compatible input: <0.4 V = shutdown (0.01 µA IQ), >1.0 V = active; must not float - tie to system PMIC or pull-up if always-on operation required. |
| FB (C3) | Feedback sense | Internally connected to 0.5 V reference; unused on fixed-output variants - leave unconnected per TI design guidelines. |
| SW (B2) | Switching node | Drives external 1.0 µH inductor; carries high di/dt square wave (0–VIN); requires shortest possible trace to inductor and minimal loop area with GND. |
Key Features
| Feature | Design Value |
|---|---|
| Automatic PFM/PWM mode switching | Transitions seamlessly between 3 MHz fixed-frequency PWM (>80 mA load) and variable-frequency PFM (<42 mA at VIN=3.6 V), optimizing efficiency across full load range without external control. |
| Internal synchronous rectification | Integrated PFET (350 mΩ) and NFET (150 mΩ) eliminate external Schottky diode, reducing conduction loss and board area while enabling >90% peak efficiency at 300 mA. |
| Soft-start circuitry | Gradually ramps switch current limit (200 → 400 → 600 → 1220 mA) during EN assertion, limiting inrush current into 10 µF output capacitor and preventing input rail sag. |
| Thermal & current protection | Combines cycle-by-cycle current limiting (1220 mA typ.) and thermal shutdown (150°C trip), allowing safe operation under short-circuit or high-ambient conditions without external supervision. |
| Minimal external component count | Requires only one 1.0 µH inductor and two ceramic capacitors (4.7 µF CIN, 10 µF COUT) - total solution size <20 mm² - ideal for slim smartphone and wearable PCBs. |
Applications
| Mobile Phone Baseband Power | Digital Camera Image Sensor Rail |
|---|---|
Use Scenario: Powers ARM Cortex-A series application processor cores requiring tightly regulated 1.5 V at up to 500 mA during video encode/decode bursts. IC Role / Device Role / Timing Role: Primary buck regulator supplying CPU I/O and memory interface voltage domain; operates in PWM mode during active processing and transitions to PFM during idle screen-off periods. Use Value: Delivers ±2.5% output accuracy and <10 µs transient response to 100 mA load steps, ensuring stable processor operation without brownout resets. | Use Scenario: Supplies 1.5 V bias to CMOS image sensor analog front-end (AFE) and column ADC during high-speed capture sequences. IC Role / Device Role / Timing Role: Low-noise, fast-transient point-of-load regulator placed adjacent to sensor die; SW node routing minimized to reduce coupling into sensitive analog pixel signals. Use Value: 3 MHz switching frequency shifts EMI energy above 20 MHz, avoiding interference with sensor clock harmonics and enabling clean 12-bit image data acquisition. |
| Portable Media Player Audio Codec | WLAN/BT Combo Module Core Supply |
Use Scenario: Provides clean 1.5 V rail to stereo audio codec DSP and DAC circuitry in MP3 players with <100 µV RMS output ripple. IC Role / Device Role / Timing Role: Secondary regulated supply derived from main 3.3 V PMIC rail; uses PFM mode during music playback pause to extend battery life. Use Value: 16 µA quiescent current in PFM mode contributes <0.5% daily battery drain during standby, enabling multi-week shelf life. | Use Scenario: Powers 1.5 V core logic of integrated Wi-Fi/Bluetooth SoC in smart speakers and IoT hubs operating from USB 5 V input. IC Role / Device Role / Timing Role: Compact, thermally efficient buck stage replacing linear regulators to meet 1 W thermal budget in sealed enclosures. Use Value: Internal synchronous FETs achieve 89% efficiency at 400 mA, reducing junction temperature rise by 18°C versus discrete MOSFET solution. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down DC-DC converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS62231DRYR | Fixed 1.5 V output, 3 MHz switching, 600 mA rating, but uses 6-pin USON (NGE0006A) instead of 5-bump DSBGA; RDS(ON) higher (PFET 450 mΩ, NFET 200 mΩ). | Same load capability and efficiency profile, but larger 2.0 mm × 2.0 mm USON footprint increases PCB area by 300%. | Select when board layout allows larger package and thermal pad access is less constrained than in ultra-thin mobile designs. |
| AP63201WS-15 | Fixed 1.5 V, 600 mA, 3 MHz, but lacks automatic PFM/PWM mode switching - operates in forced-PWM only, resulting in 45 µA typical IQ vs. 16 µA. | Better EMI predictability due to fixed frequency, but 2.8× higher light-load current reduces battery life in always-on sensor nodes. | Select for noise-sensitive RF coexistence testing where deterministic 3 MHz spectral content is preferred over adaptive efficiency. |
Compared with TPS62231DRYR and AP63201WS-15, the LM3677LEX-1.5/NOPB offers the smallest footprint (1.0 mm²), lowest quiescent current in light load, and tightest output tolerance - making it optimal for volume production of space- and battery-limited consumer electronics where BOM cost and PCB real estate are critical.
Availability
LM3677LEX-1.5/NOPB is available at Aetrix Electronics and suitable for mobile phones, digital still cameras, and portable media players requiring stable component supply, long-term lifecycle support, and consistent parametric performance across manufacturing lots.
Supply support for LM3677LEX-1.5/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 with broad automotive, industrial, and personal electronics reach.
The LM3677 product line was designed specifically for ultra-low-voltage, high-efficiency power conversion in battery-powered portable devices - emphasizing minimal external components, sub-1 mm profile packaging, and intelligent light-load efficiency modes.
FAQ
What is the recommended inductor value for LM3677LEX-1.5/NOPB?
A 1.0 µH shielded inductor with ≥1375 mA saturation current rating is recommended for LM3677LEX-1.5/NOPB. This value balances efficiency, transient response, and physical size - supporting full 600 mA load while maintaining <10% peak-to-peak output ripple. TI's suggested part is MIPSA2520D 1R0 (FDK), which fits the 2.5 mm × 2.0 mm footprint and has ≤100 mΩ DCR for minimal conduction loss. The LM3677LEX-1.5/NOPB datasheet specifies this inductor value in all typical application circuits.
Can LM3677LEX-1.5/NOPB operate from a 2.5 V input?
No - LM3677LEX-1.5/NOPB requires minimum 2.7 V input per its Absolute Maximum Ratings and Operating Ratings tables. At 2.5 V, the device may fail to start or exhibit unstable regulation due to insufficient headroom for the internal PFET gate drive and reference circuitry. For 2.5 V input systems, consider the LM3677LEX-1.2/NOPB variant, which is validated down to 2.7 V input but derated to 5.0 V max for 1.2 V output. The LM3677LEX-1.5/NOPB specification explicitly defines 2.7 V as the lower bound.
Is the FB pin used on LM3677LEX-1.5/NOPB?
No - the FB pin is not connected internally on the LM3677LEX-1.5/NOPB fixed-output variant. TI's datasheet states "For fixed-output versions, the FB pin is not used and should be left unconnected." Unlike adjustable versions (e.g., LM3677-ADJ), this part uses factory-laser-trimmed feedback to set 1.5 V output; connecting external resistors or capacitors to FB will disrupt regulation. The LM3677LEX-1.5/NOPB pinout diagram confirms FB (C3) as a no-connect terminal.
What is the thermal resistance (θJA) of LM3677LEX-1.5/NOPB in its DSBGA package?
The junction-to-ambient thermal resistance (θJA) for LM3677LEX-1.5/NOPB in the 5-bump DSBGA package is 117°C/W, measured on a standard 4-layer JEDEC test board. This value is higher than the USON variant (85°C/W) due to the DSBGA's smaller thermal pad area and reliance on solder ball conduction. Designers must ensure adequate copper pour under the thermal pad and use ≥6 thermal vias to inner ground planes to approach this spec. The LM3677LEX-1.5/NOPB datasheet lists this θJA in the Thermal Properties table.
Does LM3677LEX-1.5/NOPB support forced PWM mode?
No - LM3677LEX-1.5/NOPB does not support forced PWM mode; it exclusively uses automatic PFM/PWM mode switching based on load current. There is no pin, register, or external configuration to disable PFM operation. When load drops below ~42 mA (at VIN = 3.6 V), the device autonomously enters PFM to reduce quiescent current from 35 µA (PWM) to 16 µA (PFM). This behavior is hardwired in the control logic of the LM3677LEX-1.5/NOPB and cannot be overridden.
LM3677LEX-1.5/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 6-UFDFN
- 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):
- 2.7V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 1.5V
- Voltage - Output (Max):
- -
- Current - Output:
- 600mA
- Frequency - Switching:
- 3MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -30°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 6-USON (2x1.5)
LM3677LEX-1.5/NOPB FAQ
1.How can I place an order for LM3677LEX-1.5/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3677LEX-1.5/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 LM3677LEX-1.5/NOPB reliable?
The price and inventory of LM3677LEX-1.5/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3677LEX-1.5/NOPB is usually 5 days.
3.What payment methods are accepted for LM3677LEX-1.5/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3677LEX-1.5/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3677LEX-1.5/NOPB?
LM3677LEX-1.5/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3677LEX-1.5/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 LM3677LEX-1.5/NOPB?
For technical support, including LM3677LEX-1.5/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3677LEX-1.5/NOPB requirements.
6.How does Aetrix verify that LM3677LEX-1.5/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3677LEX-1.5/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 LM3677LEX-1.5/NOPB meets industry standards.
7.What is the process for return or replacement of LM3677LEX-1.5/NOPB?
All LM3677LEX-1.5/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3677LEX-1.5/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 LM3677LEX-1.5/NOPB part is unused and in its original packaging.
Return procedure for LM3677LEX-1.5/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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