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Texas Instruments LM3668SD-2833/NOPB
- Part No.:
- LM3668SD-2833/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 12-WFDFN Exposed Pad
- Datasheet:
-
LM3668SD-2833/NOPB.pdf
- Description:
- IC REG BUCK BOOST PROG 1A 12WSON
- Quantity:
- Payment:
- Shipping:
Inventory:2,299
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Product details
Overview
LM3668SD-2833/NOPB from Texas Instruments is a synchronous dual-mode buck-boost DC-DC converter delivering regulated 2.8 V or 3.3 V outputs from 2.5 V–5.5 V input, supporting up to 1-A load current at VIN ≥ 2.8 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-2833/NOPB datasheet, LM3668SD-2833/NOPB pinout, LM3668SD-2833/NOPB application, or LM3668SD-2833/NOPB equivalent, key selection criteria include output voltage selectability (VSEL logic-controlled), 45-µA typical quiescent current in PFM mode, thermal shutdown at 150°C, 0.01-µA shutdown current, and WSON-12 package compatibility with compact 3.0 mm × 3.0 mm PCB layouts.
Technical Context
The LM3668SD-2833/NOPB implements a four-switch buck-boost topology with two integrated N-channel and two P-channel MOSFETs, enabling seamless mode transition between buck (VIN > VOUT) and boost (VIN < VOUT) without discontinuity. Its voltage-mode control architecture uses an internal error amplifier comparing FB voltage to a 0.6-V reference, with MODE/SYNC pin selecting either automatic PFM-PWM hysteresis or forced PWM operation.
Switching behavior is governed by real-time monitoring of inductor current and output regulation error: in buck mode, P2 remains on while P1/N1 switch; in boost mode, P1 remains on while N2/P2 switch. The device includes undervoltage protection (~2 V threshold), short-circuit current limiting (reduced to ~0.9 A during fault), and soft-start with ≤600-µs ramp time after VIN stabilization.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output voltages | 2.8 V (VSEL = low) or 3.3 V (VSEL = high); selectable via single logic input |
| Input voltage range | 2.5 V to 5.5 V; supports full Li-Ion battery discharge curve (3.0–4.2 V) plus USB/adapter rails |
| Max output current | 1 A at VIN ≥ 2.8 V and VOUT = 2.8/3.3 V; enables direct powering of baseband processors or RF modules |
| Quiescent current | 45 µA typical in PFM mode; extends standby battery life in always-on peripherals |
| Switching frequency | 2.2 MHz typical (PWM mode); allows use of 2.2-µH inductor and small ceramic capacitors (10 µF CIN, 22 µF COUT) |
| Shutdown current | 0.01 µA typical; minimizes battery drain when system is powered off |
| Thermal shutdown | 150°C trip point; protects die under sustained overload or poor PCB thermal design |
Pinout & Package
The LM3668SD-2833/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) requiring connection to SGND for optimal thermal performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VOUT | Regulated output node | Connects directly to output capacitor; delivers stable 2.8 V or 3.3 V to load |
| SW2 | Switching node (P2/N2) | Internal connection to PFET P2 and NFET N2; requires low-inductance layout to minimize EMI |
| PGND | Power ground return | High-current return path for power switches; must be separated from SGND and tied at single point |
| SW1 | Switching node (P1/N1) | Internal connection to PFET P1 and NFET N1; critical for buck/boost transition integrity |
| PVIN | Power input supply | Connects to input capacitor; supplies gate drive and power switches independently of VDD |
| EN | Enable control input | Active-high digital enable; pulling low disables converter and reduces current to 0.01 µA |
| VDD | Signal supply input | Provides bias for control circuitry; recommended 1-µF ceramic decoupling close to pin |
| NC | No-connect terminal | Must be connected to SGND on PCB; not internally bonded |
| SGND | Analog/control ground | Reference for FB, VSEL, MODE/SYNC, and error amplifier; separate from PGND |
| MODE/SYNC | Mode control or clock sync | Low = auto PFM-PWM; high = forced PWM; external 1.6–2.7 MHz clock accepted when high |
| VSEL | Output voltage select | Logic-low → 2.8 V; logic-high → 3.3 V; sets feedback divider ratio internally |
| FB | Feedback input | Monitors VOUT via internal resistor divider; connects externally only if custom output voltage needed |
Key Features
| Feature | Design Value |
|---|---|
| Single-inductor dual-mode conversion | Eliminates need for separate buck and boost ICs; reduces BOM count and board area in dual-rail systems |
| Automatic PFM-PWM mode transition | Maintains >85% efficiency across 10-µA to 1-A load range without manual mode control |
| Internal synchronous rectification | Replaces external Schottky diodes; achieves typical 92% peak efficiency at 500 mA (VIN = 3.6 V, VOUT = 3.3 V) |
| VSEL-configurable dual output | Hardware-selectable 2.8 V/3.3 V outputs simplify design reuse across product variants without firmware change |
| Integrated soft-start | Prevents inrush current and output overshoot during power-up; max 600-µs startup time ensures reliable sequencing |
Applications
| Handset Peripherals | MP3 Players |
|---|---|
Use Scenario: Powering camera modules, touch controllers, or audio codecs in smartphones where input voltage varies from 4.2 V (charged Li-Ion) down to 2.8 V (discharged). IC Role / Device Role / Timing Role: Primary voltage regulator supplying stable 2.8 V or 3.3 V to low-power analog/digital peripherals. Use Value: Seamless buck-boost transition prevents brownout during battery sag; 45-µA PFM current preserves standby time. | Use Scenario: Supplying DSP, flash memory, and display drivers in portable audio players operating from single-cell Li-Ion batteries. IC Role / Device Role / Timing Role: Efficient DC-DC conversion delivering regulated 3.3 V rail from dynamically varying battery voltage. Use Value: 2.2-MHz switching enables ultra-compact filter design (2.2 µH + 22 µF); WSON-12 footprint saves space in thin form factors. |
| PDAs | Portable Hard Disk Drives |
Use Scenario: Providing clean 3.3 V power to microcontrollers and interface ICs in handheld computing devices with aggressive power budgets. IC Role / Device Role / Timing Role: Main system regulator managing dynamic load transients during CPU wake/sleep cycles. Use Value: Load transient response < 50 µs (buck mode) and < 100 µs (boost mode) maintains stable core voltage during burst activity. | Use Scenario: Regulating 2.8 V for HDD spindle motor drivers and 3.3 V for SATA controller logic in external storage enclosures. IC Role / Device Role / Timing Role: Dual-output capable regulator supporting mixed-voltage subsystems from one battery source. Use Value: VSEL pin enables hardware-based voltage selection matching different drive requirements without redesign. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-mode buck-boost regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS63020DSJR | Higher 2-A output capability; 2.5-V–6-V input; 3.3-V fixed output only (no VSEL) | Requires external resistors for 2.8-V operation; lacks VSEL simplicity for dual-voltage designs | Choose when higher current or wider input range is required, and dual output voltage is not needed. |
| MAX8646ETA+ | 3-MHz switching; 1.2-A max; supports 2.5–3.3 V programmable output via I²C, not VSEL | Requires digital interface and firmware support; no hardware-selectable dual voltage | Choose when programmable output and telemetry are prioritized over pin-strapped simplicity and low quiescent current. |
Compared with TPS63020DSJR and MAX8646ETA+, the LM3668SD-2833/NOPB uniquely offers hardware-selectable 2.8 V/3.3 V outputs via VSEL, 45-µA PFM quiescent current, and seamless buck-boost transition-making it optimal for cost-sensitive, firmware-light portable systems needing dual-rail flexibility in minimal area.
Availability
LM3668SD-2833/NOPB is available at Aetrix Electronics and suitable for handset peripherals, MP3 players, and PDAs requiring stable component supply with consistent WSON-12 packaging, long-term lifecycle support, and traceable sourcing from authorized channels.
Supply support for LM3668SD-2833/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 LM3668 product line was designed specifically for single-cell Li-Ion battery-powered portable devices requiring compact, efficient, and flexible dual-mode voltage regulation without external programming interfaces.
FAQ
What output voltages does the LM3668SD-2833/NOPB support?
The LM3668SD-2833/NOPB supports two factory-configured output voltages: 2.8 V when the VSEL pin is logic-low (connected to SGND), and 3.3 V when VSEL is logic-high (connected to VIN or VDD). These values are fixed per device variant and cannot be adjusted externally beyond this binary selection.
How does the LM3668SD-2833/NOPB handle transitions between buck and boost modes?
The LM3668SD-2833/NOPB uses an internal voltage-mode control loop that continuously monitors the feedback error signal relative to a center threshold (Vcenter) to determine operating mode. When VIN > VOUT, it operates in buck mode with P2 always on; when VIN < VOUT, it switches to boost mode with P1 always on-ensuring continuous regulation without output discontinuity or audible artifacts.
What is the purpose of the MODE/SYNC pin on the LM3668SD-2833/NOPB?
The MODE/SYNC pin on the LM3668SD-2833/NOPB serves dual functions: pulled low, it enables automatic PFM-PWM mode transition for optimal light-load efficiency; pulled high, it forces continuous PWM operation or accepts an external 1.6–2.7 MHz synchronization clock to eliminate beat frequencies in multi-rail systems.
Can the LM3668SD-2833/NOPB be used with input voltages below 2.5 V?
No-the LM3668SD-2833/NOPB has a specified minimum input voltage of 2.5 V per its Recommended Operating Conditions. Operation below this level risks undervoltage lockout activation (UVP threshold ~2 V) and may result in unregulated output or device shutdown; it is not characterized or guaranteed for sub-2.5-V operation.
What thermal considerations apply to the LM3668SD-2833/NOPB in high-current applications?
The LM3668SD-2833/NOPB features thermal shutdown at ~150°C and has a junction-to-board thermal resistance (RθJB) of 21.6°C/W. For 1-A loads, ensure the DAP is soldered to a minimum 100-mm² copper pour connected to SGND, and limit ambient temperature to ≤85°C per datasheet specifications to avoid derating or intermittent shutdown.
LM3668SD-2833/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 12-WFDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- 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):
- 2.8V, 3.3V
- 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-2833/NOPB FAQ
1.How can I place an order for LM3668SD-2833/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3668SD-2833/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-2833/NOPB reliable?
The price and inventory of LM3668SD-2833/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-2833/NOPB is usually 5 days.
3.What payment methods are accepted for LM3668SD-2833/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3668SD-2833/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3668SD-2833/NOPB?
LM3668SD-2833/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3668SD-2833/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-2833/NOPB?
For technical support, including LM3668SD-2833/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3668SD-2833/NOPB requirements.
6.How does Aetrix verify that LM3668SD-2833/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3668SD-2833/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-2833/NOPB meets industry standards.
7.What is the process for return or replacement of LM3668SD-2833/NOPB?
All LM3668SD-2833/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3668SD-2833/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-2833/NOPB part is unused and in its original packaging.
Return procedure for LM3668SD-2833/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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