My Inquiry
My Account
Texas Instruments LM3678SDX-1.2/NOPB
- Part No.:
- LM3678SDX-1.2/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 10-WFDFN Exposed Pad
- Datasheet:
-
LM3678SDX-1.2/NOPB.pdf
- Description:
- IC REG BUCK PROG 1.5A 10SON
- Quantity:
- Payment:
- Shipping:
Inventory:4,004
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LM3678SDX-1.2/NOPB from Texas Instruments is a high-performance, synchronous step-down DC-DC converter optimized for single-cell Li-Ion battery-powered handheld devices. It delivers up to 1.5 A at a fixed 1.2 V output, operates from 2.5 V to 5.5 V input, features 3.3 MHz fixed-frequency PWM control, and achieves >90% peak efficiency at 500 mA with VIN = 3.6 V - enabling compact power delivery in smartphones and portable media players.
For engineers reviewing the LM3678SDX-1.2/NOPB datasheet, LM3678SDX-1.2/NOPB pinout, LM3678SDX-1.2/NOPB application, or LM3678SDX-1.2/NOPB equivalent, key selection considerations include its 10-pin WSON (DSC) package, ±3% output voltage precision, 0.01 µA shutdown current, internal soft-start, and integrated PFET/NFET synchronous rectification with 150 mΩ / 110 mΩ typical RDS(ON).
Technical Context
The LM3678SDX-1.2/NOPB implements a voltage-mode PWM controller with input voltage feed-forward for stable line regulation across its 2.5–5.5 V input range. Its 3.3 MHz switching frequency enables use of a 1 µH inductor and ultra-compact external components - total solution size under 33 mm².
Internal synchronous rectification replaces the external Schottky diode, reducing conduction loss and improving light-load efficiency. Protection features include cycle-by-cycle current limiting (2.15 A typ), thermal shutdown (150°C), undervoltage lockout, and PGOOD flag with ±7.5% output voltage monitoring.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 1.2 V ±3% - eliminates external feedback resistors and ensures stable core voltage for low-power processors. |
| Input Voltage Range | 2.5 V to 5.5 V - supports full discharge curve of single Li-Ion cell (2.7 V–4.2 V) plus USB/adapter rails. |
| Max Output Current | 1.5 A continuous - sufficient for application processors, RF transceivers, and display drivers in handhelds. |
| Switching Frequency | 3.3 MHz (typ), 2.7–3.6 MHz (min–max) - enables tiny 1 µH inductors and reduces EMI fundamental frequency. |
| Shutdown Current | 0.01 µA (typ) - minimizes battery drain during system sleep or off-state in always-on portable devices. |
| Feedback Reference | 0.5 V internal reference - used with internal resistor divider to set 1.2 V output; no external FB network required. |
| Thermal Shutdown | Activates at TJ = 150°C (typ), releases at 130°C - protects against sustained overload or poor PCB thermal design. |
Pinout & Package
LM3678SDX-1.2/NOPB uses a 3 mm × 3 mm, 10-pin WSON (DSC) package with exposed die attach pad (DAP) for enhanced thermal performance. The DAP must be soldered to PCB ground plane but not used as primary ground path.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2 | GND | Power and analog ground pins - require low-impedance connection to PCB ground plane; pin 1 is power ground, pin 2 is analog ground. |
| 3 | SW | Switching node - connects internally to PFET drain and NFET source; carries high dv/dt and high di/dt; must be routed short and away from noise-sensitive traces. |
| 4, 5 | VDD | Analog and power supply inputs - connect jointly to input filter capacitor (10 µF ceramic); decouples internal bias and switch drive circuits. |
| 6 | VSELECT | Output voltage select logic input - tied HIGH (≥1.2 V) to configure 1.2 V output; unused in this fixed-voltage variant but must be terminated. |
| 7 | PGOOD | Open-drain power-good flag - pulled low when VOUT deviates >±7.5% from regulation; used for system sequencing and fault detection. |
| 8 | PWM | PWM mode enable - must be connected to VIN to activate fixed-frequency PWM operation (not PFM). |
| 9 | EN | Enable control - device enabled when EN ≥1.0 V; disabled (shutdown) when EN ≤0.4 V; must not float. |
| 10 | FB | Feedback input - internally connected to fixed 1.2 V divider; leave unconnected in this variant (no external resistor network required). |
| DAP | Die Attach Pad | Thermal pad - soldered to PCB ground pour to improve θJA (49.8°C/W on 4-layer board); enhances thermal reliability under 1.5 A load. |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous Rectification | Integrated PFET (150 mΩ typ) + NFET (110 mΩ typ) - eliminates external Schottky diode, improves efficiency by 5–10% vs. asynchronous designs at 1.2 V. |
| High-Frequency PWM | 3.3 MHz fixed switching - allows 1 µH inductor and 10 µF/22 µF ceramic input/output capacitors, minimizing board area and cost. |
| Soft Start | Controlled in-rush current ramp - prevents input voltage droop and output overshoot during startup; activates only after VIN ≥2.5 V and EN rising edge. |
| Current Limit Protection | 2.15 A (typ) cycle-by-cycle limit - prevents damage during short-circuit or overload; includes timed NFET conduction for safe inductor current decay. |
| Low Quiescent Current | 0.01 µA shutdown, ~400 µA no-load IQ in PWM mode - extends battery life in standby without compromising transient response. |
Applications
| Smartphone Core Power | USB Modem Baseband Supply |
|---|---|
Use Scenario: Powers ARM Cortex-A series application processor core rail in dual-mode smartphones operating from single Li-Ion cell. IC Role / Device Role / Timing Role: Primary synchronous buck regulator delivering regulated 1.2 V at up to 1.5 A with fast load transient response (<10 µs recovery). Use Value: Enables high-performance processing while maintaining >85% efficiency at 1 A load and <10 mV output ripple - critical for digital logic stability. |
Use Scenario: Supplies 1.2 V to baseband IC and RF transceiver in USB-connected LTE modems powered via 5 V USB bus. IC Role / Device Role / Timing Role: Intermediate voltage regulator stepping down from internal 3.3 V LDO output to 1.2 V core rail; handles pulsed transmit current bursts. Use Value: Delivers 1.5 A peak current with <20 mV undershoot during 0→1 A load steps - prevents baseband reset or data corruption during transmission. |
| Portable Media Player SoC | Digital Still Camera Image Processor |
Use Scenario: Provides 1.2 V core voltage to multimedia SoC in flash-based audio/video players with OLED display backlight. IC Role / Device Role / Timing Role: High-efficiency point-of-load converter with PGOOD signaling to enable SoC boot sequence only after stable 1.2 V is established. Use Value: Achieves 90%+ efficiency at 500 mA, reducing thermal load in sealed plastic enclosure and extending playback time per charge. |
Use Scenario: Powers image signal processor (ISP) and embedded DRAM in compact digital still cameras using Li-Poly battery. IC Role / Device Role / Timing Role: Low-noise, fast-transient buck regulator supporting burst-mode ISP operation during image capture and preview. Use Value: Maintains <±1% output regulation during 100 mA → 1.2 A load transitions - ensures consistent color accuracy and reduced image artifacts. |
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 1.2 V, 1.8 A max, 3.6 MHz, 12-pin WSON - higher current rating and slightly higher switching frequency; requires different PCB footprint. | Supports higher peak loads in next-gen processors; less suitable for space-constrained legacy layouts due to larger package. | Select when >1.5 A capability or tighter output tolerance (±1.5%) is required; verify thermal margin with 12-pin layout. |
| RT8059GJ6 | Fixed 1.2 V, 1.5 A max, 3 MHz, 6-pin SOT-23 - smaller package but lower efficiency (~82% at 1 A) and no PGOOD or thermal shutdown. | Limited to low-complexity, cost-sensitive applications where protection features and precision are secondary. | Choose only for non-critical subsystems with relaxed reliability requirements; avoid in battery-critical or thermally constrained designs. |
Compared with TPS62231DRYR and RT8059GJ6, the LM3678SDX-1.2/NOPB offers optimal balance of compact 10-pin WSON footprint, robust protection (PGOOD, thermal shutdown, current limit), and verified 90%+ efficiency at 1.2 V - making it preferred for production-grade handheld power rails where reliability and board area are co-prioritized.
Availability
LM3678SDX-1.2/NOPB is available at Aetrix Electronics and suitable for smartphone core power, USB modem baseband supply, and portable media player SoC applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for LM3678SDX-1.2/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 specializing in analog, embedded processing, and power management technologies, with decades of expertise in high-efficiency DC-DC conversion for portable electronics.
The LM3678 product line was designed specifically for miniature, high-frequency step-down regulation in battery-powered handheld devices - emphasizing minimal external component count, thermal robustness in small form factors, and seamless integration with Li-Ion battery voltage profiles.
FAQ
What is the recommended input capacitor for LM3678SDX-1.2/NOPB?
A 10 µF, 6.3 V X5R/X7R ceramic capacitor (e.g., 0805 case) is recommended for LM3678SDX-1.2/NOPB. It must be placed directly between VIN and GND pins with minimal trace length to suppress high-frequency switching noise and supply transient current. TI specifies GRM21BR60J106K (Murata) and JMK212BJ106K (Taiyo Yuden) as validated options.
Does LM3678SDX-1.2/NOPB require external feedback resistors?
No, LM3678SDX-1.2/NOPB does not require external feedback resistors. It is a fixed-output variant with an internal resistor divider referenced to a 0.5 V bandgap, delivering precisely 1.2 V ±3%. The FB pin is internally connected and must remain unconnected on the PCB.
How is the 1.2 V output selected on LM3678SDX-1.2/NOPB?
The 1.2 V output on LM3678SDX-1.2/NOPB is factory-configured and fixed; the VSELECT pin is not functional in this variant. While the datasheet notes VSELECT = HIGH selects 1.2 V in adjustable versions, LM3678SDX-1.2/NOPB uses internal hard-wired logic and requires VSELECT to be tied to VIN or left floating only if explicitly permitted - TI recommends tying it HIGH for consistency.
What thermal design guidance applies to LM3678SDX-1.2/NOPB?
LM3678SDX-1.2/NOPB requires soldering the exposed DAP to a minimum 100 mm² copper pour connected to PCB ground via ≥4 thermal vias (0.3 mm diameter). On a 4-layer board, this achieves θJA = 49.8°C/W. Without proper DAP grounding, junction temperature can exceed 125°C at 1.5 A load, triggering thermal shutdown.
Can LM3678SDX-1.2/NOPB operate in PFM mode?
No, LM3678SDX-1.2/NOPB operates exclusively in PWM mode. The PWM pin must be connected to VIN to enable fixed-frequency operation. It lacks PFM capability - unlike some other TI buck converters, this variant does not auto-switch to discontinuous conduction mode for light loads.
What is the maximum allowable input voltage for LM3678SDX-1.2/NOPB?
The absolute maximum input voltage for LM3678SDX-1.2/NOPB is 6.0 V, but the recommended operating range is 2.5 V to 5.5 V. Exceeding 5.5 V risks exceeding internal PFET gate oxide limits and may cause premature failure, even briefly. Applications powered from 5 V USB must ensure no overshoot exceeds 5.5 V.
LM3678SDX-1.2/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 10-WFDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Programmable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.5V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 0.8V, 1.2V
- Voltage - Output (Max):
- -
- Current - Output:
- 1.5A
- Frequency - Switching:
- 3.3MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -30°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-SON (3x3)
LM3678SDX-1.2/NOPB FAQ
1.How can I place an order for LM3678SDX-1.2/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3678SDX-1.2/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 LM3678SDX-1.2/NOPB reliable?
The price and inventory of LM3678SDX-1.2/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3678SDX-1.2/NOPB is usually 5 days.
3.What payment methods are accepted for LM3678SDX-1.2/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3678SDX-1.2/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3678SDX-1.2/NOPB?
LM3678SDX-1.2/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3678SDX-1.2/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 LM3678SDX-1.2/NOPB?
For technical support, including LM3678SDX-1.2/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3678SDX-1.2/NOPB requirements.
6.How does Aetrix verify that LM3678SDX-1.2/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3678SDX-1.2/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 LM3678SDX-1.2/NOPB meets industry standards.
7.What is the process for return or replacement of LM3678SDX-1.2/NOPB?
All LM3678SDX-1.2/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3678SDX-1.2/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 LM3678SDX-1.2/NOPB part is unused and in its original packaging.
Return procedure for LM3678SDX-1.2/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM3678SDX-1.2/NOPB 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…
