LM3668SD-3.3 Texas Instruments Integrated Circuit (Small Outline No-lead) In Stock
Texas Instruments LM3668SD-3.3 is a dual buck/boost switching controller delivering 1 A output at 3.3 V with a 2500 kHz switching frequency. It accepts a 2.5 V to 5.5 V input range and uses PWM voltage-mode control with optional PFM for light-load efficiency. Packaged in a 12-pin LLP for space-constrained portable applications.
- Manufacturer
- Texas Instruments
- Package
- Small Outline No-lead
- Pin Count
- 12
- Lifecycle
- OBSOLETE
- Datasheet
- LM3668SD-3.3 Datasheet PDF
- Category
- Integrated Circuit
- Temp Range
- -40.0°C to 85.0°C
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
What are the key features of LM3668SD-3.3?
- Buck/boost topology maintains a regulated 3.3 V output across a 2.5 V to 5.5 V input range without interruption
- 2500 kHz switching frequency minimizes external inductor and capacitor size for compact 12-pin LLP designs
- Dual PWM voltage-mode control with optional pulse frequency modulation for improved light-load efficiency
- 1 A continuous output current capability supports a wide range of portable and battery-powered loads
What is LM3668SD-3.3 used for?
The LM3668SD-3.3 is designed for single-cell Li-ion and alkaline battery-powered devices such as portable scanners, handheld instruments, and wireless sensor nodes that require a stable 3.3 V rail throughout the battery discharge cycle. Its 2500 kHz switching frequency allows very small passive components, enabling ultra-compact power modules. The dual-mode PWM/PFM control extends battery life in always-on IoT designs operating across a 2.5 V to 5.5 V input range.
What are the specifications of LM3668SD-3.3?
| Pbfree Code | Yes |
| Reach Compliance Code | Compliant |
| YTEOL | 0 |
| Additional Feature | PULSE FREQUENCY MODULATION TECHNIQUE ALSO AVAILABLE |
| Analog IC - Other Type | DUAL SWITCHING CONTROLLER |
| Control Mode | VOLTAGE-MODE |
| Control Technique | PULSE WIDTH MODULATION |
| Input Voltage-Max | 5.5V |
| Input Voltage-Min | 2.5V |
| Input Voltage-Nom | 3.6V |
| JESD-30 Code | S-XDSO-N12 |
| JESD-609 Code | e3 |
| Number of Functions | 1 |
| Output Current-Max | 2.05A |
| Package Body Material | UNSPECIFIED |
| Package Equivalence Code | SOLCC12,.12,16 |
| Package Shape | SQUARE |
| Package Style | SMALL OUTLINE, HEAT SINK/SLUG, VERY THIN PROFILE |
| Peak Reflow Temperature (Cel) | 260 |
| Qualification Status | Not Qualified |
| Surface Mount | YES |
| Switcher Configuration | BUCK-BOOST |
| Switching Frequency-Max | 2500kHz |
| Temperature Grade | INDUSTRIAL |
| Terminal Finish | Matte Tin (Sn) |
| Terminal Form | NO LEAD |
| Terminal Pitch | 0.4mm |
| Terminal Position | DUAL |
| Time@Peak Reflow Temperature-Max (s) | 40 |
| Package | Small Outline No-lead |
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
| Moisture Sensitivity Level | MSL 1 |
| ECCN | EAR99 |
| HTS Code | 8542.39.00.60 |
Where can I find the LM3668SD-3.3 datasheet?
LM3668SD-3.3 Datasheet DownloadOfficial datasheet from Texas Instruments
What are equivalent replacements for LM3668SD-3.3?
Compatible alternatives and drop-in replacements for LM3668SD-3.3:
Dual Switching Controller, Voltage-mode, 2.05A, 2500kHz Switching Freq-Max, CMOS, PDSO12
Dual Switching Controller, Voltage-mode, 2.05A, 2500kHz Switching Freq-Max, CMOS, PDSO12
Frequently Asked Questions
How does the LM3668SD-3.3 maintain a 3.3 V output when the battery voltage drops below 3.3 V?
The LM3668SD-3.3 uses a buck/boost topology that seamlessly transitions between step-down and step-up conversion, keeping the output at a fixed 3.3 V even when the input falls anywhere in the 2.5 V to 5.5 V range. This makes it ideal for single-cell Li-ion batteries that discharge from 4.2 V down to around 2.7 V without any output drop.
What switching frequency does LM3668SD-3.3 use, and how does it affect external component selection?
LM3668SD-3.3 switches at 2500 kHz, which is significantly higher than typical 300-600 kHz buck converters. This high frequency allows the use of smaller inductors and output capacitors, reducing total solution size. For example, a 1 µH inductor and 10 µF ceramic capacitors may be sufficient, compared to much larger values needed at lower frequencies.
Which power management scenarios justify choosing LM3668SD-3.3 over a simple LDO regulator?
LM3668SD-3.3 is preferred over an LDO when the input voltage can fall below the required 3.3 V output, making a linear regulator physically impossible to use. Its switching efficiency also delivers substantially higher power conversion efficiency—often above 90%—compared to the poor efficiency of an LDO operating with a small dropout. Battery-powered portable devices benefit especially from this trade-off, gaining longer runtime from a 1 A, 3.3 V regulated rail.
How does pulse frequency modulation improve LM3668SD-3.3 efficiency at light loads?
At light loads below approximately 100 mA, PFM mode reduces switching losses by lowering the switching frequency proportionally to output power demand. This keeps the efficiency above 80% even at milliamp-level loads, extending battery life in sleep-mode IoT nodes that need a steady 3.3 V rail but spend most time drawing very little current from the 2.5 V to 5.5 V input supply.
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About Texas Instruments
Texas Instruments (TI) is a global semiconductor company headquartered in Dallas, Texas. TI designs and manufactures analog and embedded processing chips used in industrial, automotive, consumer, communications, and enterprise systems.
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