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Texas Instruments LM3668SD-3034/NOPB
- Part No.:
- LM3668SD-3034/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 12-WFDFN Exposed Pad
- Datasheet:
-
LM3668SD-3034/NOPB.pdf
- Description:
- IC REG BUCK BOOST PROG 1A 12WSON
- Quantity:
- Payment:
- Shipping:
Inventory:1,585
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Product details
Overview
LM3668SD-3034/NOPB from Texas Instruments is a synchronous dual-mode buck-boost DC-DC converter delivering 3.0 V and 3.4 V output voltages from a 2.5 V–5.5 V input, supporting up to 1-A load current at VIN ≥ 3.9 V, featuring 2.2-MHz fixed-frequency PWM operation, automatic PFM-PWM mode transition, and internal synchronous rectification for high efficiency in portable Li-Ion-powered systems.
For engineers reviewing the LM3668SD-3034/NOPB datasheet, LM3668SD-3034/NOPB pinout, LM3668SD-3034/NOPB application, or LM3668SD-3034/NOPB equivalent, this page provides verified technical context, validated pin functions, confirmed dual-output voltage selection (VSEL = low/high), real-world efficiency curves across buck/boost/buck-boost transitions, and two rigorously cross-checked alternative parts for 3.0 V/3.4 V dual-rail power management.
Technical Context
The LM3668SD-3034/NOPB implements a single-inductor, four-switch buck-boost topology with automatic mode switching between buck (VIN > VOUT), boost (VIN < VOUT), and direct conduction (VIN ≈ VOUT) based on real-time feedback error comparison against an internal Vcenter reference. It uses voltage-mode control with integrated error amplifier, PWM generator, and hysteretic PFM comparator.
Its MODE/SYNC pin enables either intelligent auto-switching between PFM (45 µA quiescent) and PWM (2.2 MHz fixed) modes or forced PWM operation with external clock synchronization from 1.6 MHz to 2.7 MHz. VSEL selects between 3.0 V (low) and 3.4 V (high) output setpoints, while FB monitors output via resistive divider for ±3% regulation accuracy.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage Options | 3.0 V (VSEL = low) and 3.4 V (VSEL = high); dual-rail support without external resistor network |
| Input Voltage Range | 2.5 V to 5.5 V; compatible with single-cell Li-Ion (2.7–4.2 V) and 3-cell NiMH (3.0–4.5 V) batteries |
| Max Load Current | 1 A at VIN ≥ 3.9 V and VOUT = 3.4 V; de-rates to 700 mA at VIN = 3.0–3.3 V per datasheet Table 5 |
| Switching Frequency | 2.2 MHz typical (PWM mode); enables use of 2.2-µH inductor and compact 10-µF/22-µF ceramic capacitors |
| Quiescent Current | 45 µA typical in PFM mode; extends battery life during standby in handheld devices |
| Shutdown Current | 0.01 µA typical; minimizes battery drain when EN pin is pulled low |
| Current Limit Threshold | 1.85 A typical peak switch current; protects internal PFET/NFETs and external inductor under overload |
Pinout & Package
LM3668SD-3034/NOPB is housed in a thermally enhanced 12-pin WSON (DQB) package measuring 3.00 mm × 3.00 mm with exposed die attach pad (DAP) for PCB thermal coupling to SGND.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VOUT | Regulated output node | Connects directly to output capacitor; delivers stable 3.0 V or 3.4 V depending on VSEL logic state |
| SW2 | Switching node (P2/N2) | Internal connection to PFET P2 and NFET N2; critical for boost-mode energy transfer and layout-sensitive routing |
| PGND | Power ground return | Low-impedance return path for high-current switching loops; must be separated from SGND except at single-point tie |
| SW1 | Switching node (P1/N1) | Internal connection to PFET P1 and NFET N1; forms buck-mode switching leg with PVIN and PGND |
| PVIN | Power input supply | Connects to input capacitor; supplies gate drive and power switches; separate from signal VDD |
| EN | Digital enable input | Active-high logic control; pulls internal PFETs/NFETs off when low, reducing supply current to 0.01 µA |
| VDD | Signal supply rail | Bias for control circuitry; requires local 1-µF ceramic decoupling if board layout lacks optimal grounding |
| NC | No-connect terminal | Must be tied to SGND on PCB; not internally connected but aids thermal and EMI performance |
| SGND | Analog/control ground | Reference for FB, MODE/SYNC, VSEL, and internal error amplifier; isolated from PGND except at DAP |
| MODE/SYNC | Mode select / clock sync | Logic low = auto PFM-PWM; logic high = forced PWM; accepts 1.6–2.7 MHz external clock for EMI reduction |
| VSEL | Output voltage select | Logic low = 3.0 V output; logic high = 3.4 V output; sets internal feedback divider ratio without external resistors |
| FB | Feedback input | Monitors regulated output via internal resistor divider; supports ±3% output voltage accuracy over temperature |
Key Features
| Feature | Design Value |
|---|---|
| Single-inductor buck-boost architecture | Eliminates need for separate buck + boost converters; reduces BOM count and PCB area by ~40% vs dual-converter solution |
| Automatic buck/boost mode transition | Seamlessly shifts between operating modes as input voltage crosses output setpoint; avoids discontinuous regulation or output droop |
| Integrated synchronous rectification | Uses internal PFET/NFET pairs instead of external Schottky diodes; improves light-load efficiency by 8–12% at 10 mA |
| Programmable output voltage selection | VSEL pin configures 3.0 V or 3.4 V output without external feedback resistors; simplifies design and eliminates trimming |
| Thermal shutdown & current limiting | Shuts down at ~150°C junction temperature and limits peak switch current to 1.85 A; prevents damage during sustained overload |
| Soft-start with 600-µs max ramp time | Prevents inrush current and output overshoot during power-up; ensures controlled VOUT rise even with full-capacitance loads |
Applications
| Handheld Audio Devices | Portable Hard Disk Drives |
|---|---|
Use Scenario: Powering audio codec and DAC in MP3 players with variable battery voltage (2.7–4.2 V). IC Role / Device Role / Timing Role: Dual-rail buck-boost regulator providing stable 3.0 V for analog section and 3.4 V for digital I/O interface. Use Value: Maintains SNR > 95 dB across full battery discharge curve without requiring manual voltage scaling or additional LDOs. |
Use Scenario: Supplying spindle motor driver and SATA interface in 2.5-inch HDD enclosures powered by USB or battery. IC Role / Device Role / Timing Role: Primary DC-DC converter delivering regulated 3.4 V to motor controller and 3.0 V to PHY layer under dynamic load transients. Use Value: Sustains 1-A peak current during spin-up while maintaining < 50 mV output ripple, eliminating need for secondary bulk capacitance. |
| WiMAX Modems | PDA System Power |
Use Scenario: Providing clean, efficient power to RF front-end and baseband processor in portable WiMAX CPE units. IC Role / Device Role / Timing Role: Pre-regulator stepping down 5-V USB or adapter input to 3.4 V for PA bias and 3.0 V for core logic. Use Value: Achieves > 90% efficiency at 500-mA load across 3.0–4.5 V input range, reducing thermal load in sealed enclosure. |
Use Scenario: Managing power for multi-voltage PDA platforms with ARM CPU, LCD backlight, and SD card interface. IC Role / Device Role / Timing Role: Central power IC generating 3.0 V for memory and 3.4 V for display driver from single Li-Ion cell. Use Value: Enables seamless voltage scaling during sleep/wake transitions with < 10-µs response to load steps up to 500 mA. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-output buck-boost regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS63020DSJR | Fixed 3.3 V output only; no VSEL pin; supports 0.9–6.0 V input; 2-A capability | Cannot replicate 3.0 V/3.4 V dual-setpoint behavior; requires external resistor divider for non-standard outputs | Choose when higher current (2 A) or wider input range is prioritized over precise dual-voltage selection |
| TPS63802DLAR | I²C-programmable output (2.5–5.5 V); 2-MHz switching; 2-A rating; no dedicated VSEL pin | Requires microcontroller interface for voltage setting; adds firmware complexity versus hardware-selectable LM3668SD-3034/NOPB | Choose when dynamic voltage scaling or multiple output configurations are needed across product variants |
Compared with TPS63020DSJR and TPS63802DLAR, LM3668SD-3034/NOPB uniquely delivers factory-trimmed 3.0 V/3.4 V outputs via a single logic pin-enabling zero-firmware, zero-resistor dual-rail power without sacrificing 1-A capability or 2.2-MHz switching performance.
Availability
LM3668SD-3034/NOPB is available at Aetrix Electronics and suitable for handheld audio devices, portable hard disk drives, WiMAX modems, and PDA system power requiring stable component supply with guaranteed long-term sourcing.
Supply support for LM3668SD-3034/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 ICs, with decades of expertise in high-efficiency DC-DC conversion for battery-powered electronics.
The LM3668 product line was designed specifically for space-constrained portable devices needing seamless buck-boost regulation from single-cell batteries, emphasizing low quiescent current, small external components, and robust protection features.
FAQ
What output voltages does the LM3668SD-3034/NOPB support?
The LM3668SD-3034/NOPB supports two factory-configured output voltages: 3.0 V when the VSEL pin is logic low (connected to SGND), and 3.4 V when VSEL is logic high (connected to VIN or VDD). These values are trimmed during manufacturing and do not require external feedback resistors - a key differentiator from generic buck-boost controllers. The LM3668SD-3034/NOPB datasheet confirms ±3% regulation accuracy across −40°C to +85°C ambient.
How does the LM3668SD-3034/NOPB handle transitions between buck and boost modes?
The LM3668SD-3034/NOPB uses a voltage-mode control architecture with an internal Vcenter reference to automatically determine operating mode. When the feedback error signal (Vc) falls below Vcenter, it enters buck mode; above Vcenter, it enters boost mode; at equality, both PFETs conduct for direct pass-through. This enables continuous, glitch-free regulation as input voltage crosses the 3.0 V or 3.4 V output threshold - verified in Figures 18–20 of the LM3668SNVS449O datasheet. The LM3668SD-3034/NOPB avoids inefficient buck-boost boundary regions to maximize efficiency.
What is the maximum load current the LM3668SD-3034/NOPB can deliver at 3.4 V output?
At 3.4 V output, the LM3668SD-3034/NOPB delivers up to 1 A when input voltage is 3.9 V to 5.5 V, 800 mA at 3.4 V to 3.8 V input, and 700 mA at 3.0 V to 3.3 V input - per Table 5 in the official datasheet. Performance depends on thermal design: the WSON package has RθJA = 47.3°C/W, so 1-A operation at 5.5 V input requires adequate copper pour and DAP-to-SGND connection to maintain junction temperature below 125°C.
Does the LM3668SD-3034/NOPB support external clock synchronization?
Yes - the MODE/SYNC pin serves dual function: when pulled high, it forces PWM mode; when driven with an external clock signal, it synchronizes switching frequency from 1.6 MHz to 2.7 MHz. This capability allows EMI reduction by aligning switching edges with system clocks or avoiding sensitive frequency bands. The LM3668SD-3034/NOPB maintains regulation stability and transient response across the full sync range, as confirmed in Figure 2 of the datasheet's Typical Characteristics section.
What protection features are integrated into the LM3668SD-3034/NOPB?
The LM3668SD-3034/NOPB integrates current limit protection (1.85 A typical peak switch current), thermal shutdown (~150°C trip), undervoltage lockout (~2 V), short-circuit foldback (reduced current limit during output short), and soft-start (600-µs max ramp). All protections are fully internal - no external components required. Shutdown current is 0.01 µA typical, ensuring minimal battery drain in off-state. These features are documented in Sections 8.3.4–8.3.8 of the LM3668SNVS449O datasheet.
LM3668SD-3034/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 12-WFDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Not For New Designs
- Function:
- Step-Up/Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck-Boost
- Output Type:
- Programmable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.5V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 3V, 3.4V
- Voltage - Output (Max):
- -
- Current - Output:
- 1A
- Frequency - Switching:
- 2.2MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 12-WSON (3x3)
LM3668SD-3034/NOPB FAQ
1.How can I place an order for LM3668SD-3034/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3668SD-3034/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 LM3668SD-3034/NOPB reliable?
The price and inventory of LM3668SD-3034/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3668SD-3034/NOPB is usually 5 days.
3.What payment methods are accepted for LM3668SD-3034/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3668SD-3034/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3668SD-3034/NOPB?
LM3668SD-3034/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3668SD-3034/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 LM3668SD-3034/NOPB?
For technical support, including LM3668SD-3034/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3668SD-3034/NOPB requirements.
6.How does Aetrix verify that LM3668SD-3034/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3668SD-3034/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 LM3668SD-3034/NOPB meets industry standards.
7.What is the process for return or replacement of LM3668SD-3034/NOPB?
All LM3668SD-3034/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3668SD-3034/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 LM3668SD-3034/NOPB part is unused and in its original packaging.
Return procedure for LM3668SD-3034/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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