LM3311SQ Texas Instruments Integrated Circuit (Quad Flat No-Lead) In Stock
The LM3311SQ is a single-channel adjustable step-up DC-DC boost converter from Texas Instruments in a 24-pin LLP QFN package. It operates from 2.5V to 7V input using current-mode PWM control with adjustable output voltage up to 24V. Available with worldwide in-stock shipping for compact power designs.
- Manufacturer
- Texas Instruments
- Package
- Quad Flat No-Lead
- Pin Count
- 25
- Lifecycle
- OBSOLETE
- Datasheet
- LM3311SQ Datasheet PDF
- Category
- Integrated Circuit
- Temp Range
- -40.0°C to 125.0°C
- RoHS
- Non-compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
Key Features
- Current-mode PWM boost topology with adjustable output voltage supporting wide output range up to 24V
- 2.5V to 7V input voltage range compatible with single Li-ion, 3xAA, and USB 5V power sources
- 24-pin LLP QFN package with exposed pad for improved thermal dissipation in compact converter designs
- Single-channel architecture with integrated switch simplifying high-density DC-DC power stage layout
- REACH compliant construction meeting environmental regulations for commercial and industrial applications
Applications
The LM3311SQ is used in portable medical instruments, handheld test equipment, and TFT display power supplies that need a boosted rail above 7V from a Li-ion battery. Its 2.5V minimum input allows operation from near-depleted 3V coin cells or two-cell alkaline packs in wireless sensors and remote controls. Industrial handheld devices and OLED bias supply circuits rely on the adjustable output up to 24V to drive display panels and piezoelectric actuators from a single compact QFN converter.
Specifications
| Reach Compliance Code | Compliant |
| YTEOL | 0 |
| Analog IC - Other Type | SWITCHING REGULATOR |
| Control Mode | CURRENT-MODE |
| Control Technique | PULSE WIDTH MODULATION |
| Input Voltage-Max | 7V |
| Input Voltage-Min | 2.5V |
| Input Voltage-Nom | 2.5V |
| JESD-30 Code | S-XQCC-N24 |
| JESD-609 Code | e0 |
| Number of Functions | 1 |
| Output Current-Max | 2.6A |
| Package Body Material | UNSPECIFIED |
| Package Equivalence Code | LCC24,.16SQ,20 |
| Package Shape | SQUARE |
| Package Style | CHIP CARRIER, HEAT SINK/SLUG, VERY THIN PROFILE |
| Peak Reflow Temperature (Cel) | 260 |
| Qualification Status | Not Qualified |
| Surface Mount | YES |
| Switcher Configuration | BOOST |
| Switching Frequency-Max | 1280kHz |
| Temperature Grade | AUTOMOTIVE |
| Terminal Finish | Tin/Lead (Sn85Pb15) |
| Terminal Form | NO LEAD |
| Terminal Pitch | 0.5mm |
| Terminal Position | QUAD |
| Time@Peak Reflow Temperature-Max (s) | 40 |
| Package | Quad Flat No-Lead |
Compliance & Regulatory
| RoHS Status | Non-compliant |
| Lead-Free | Yes (Pb-Free) |
| Moisture Sensitivity Level | MSL 1 |
| ECCN | EAR99 |
| HTS Code | 8542.39.00.60 |
Alternate & Equivalent Parts
Compatible alternatives and drop-in replacements for LM3311SQ:
Switching Regulator, Current/voltage-mode, 2.6A, 1500kHz Switching Freq-Max, BICMOS, PQCC24
Frequently Asked Questions
What input voltage range does LM3311SQ support and which battery chemistries does it directly accommodate?
The LM3311SQ operates from 2.5V to 7V input, covering single-cell Li-ion from 2.7V to 4.2V, three alkaline AA cells at 3.6V to 4.5V, and USB 5V. This flexibility allows the same PCB design to target portable consumer, medical, and industrial power applications without changing the regulator IC or external passive components, reducing design iteration costs.
How does current-mode PWM control in LM3311SQ benefit transient response in display bias applications?
Current-mode control samples the inductor current each switching cycle, allowing the duty cycle to respond to output load steps within one switching period rather than waiting for the voltage loop to catch up. For TFT or OLED display bias supplies that experience rapid current steps of 50 mA to 200 mA during pixel refreshes, this fast inner current loop reduces output voltage overshoot and undershoot, keeping the display driver within its rated supply tolerance.
For a space-constrained medical device, what thermal advantage does the LM3311SQ's 24-pin LLP package provide?
The 24-pin LLP QFN package includes an exposed thermal pad on the bottom that conducts heat directly to the PCB copper pour, achieving a junction-to-board thermal resistance below 30°C/W. This allows the converter to deliver higher continuous output power in a 4 x 4 mm footprint compared to a plastic SOIC package of similar pin count, which relies on lead-frame conduction alone and typically exceeds 60°C/W.
When is LM3311SQ a better fit than LM2735 for a boost converter design requiring high output voltage?
LM3311SQ supports output voltages up to 24V with a 24-pin package offering more feedback and control pins for sequencing and protection features, while LM2735 in SOT-23-5 targets simpler 3V to 24V adjustable designs at lower output current. If the design requires more than 300 mA output at voltages above 15V, or needs the extra pin count for enable, power-good, and soft-start control, LM3311SQ provides the necessary headroom and feature set.
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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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