LM27402SQ Texas Instruments Integrated Circuit (Quad Flat No-Lead) In Stock
Texas Instruments LM27402SQ is a high-performance synchronous buck controller using voltage-mode PWM control with DCR current sensing, operating from 3V to 20V input and targeting 4.5V typical output. Features lossless inductor DCR current sensing, fast transient response, and fits a compact 16-pin QFN package for space-constrained power designs. Ideal for point-of-load regulation in telecom, server, and industrial power systems.
- Manufacturer
- Texas Instruments
- Package
- Quad Flat No-Lead
- Pin Count
- 16
- Lifecycle
- OBSOLETE
- Datasheet
- LM27402SQ Datasheet PDF
- Category
- Integrated Circuit
- Temp Range
- -40.0°C to 125.0°C
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
Key Features
- Voltage-mode PWM synchronous buck controller with 3V to 20V input range and lossless DCR inductor current sensing
- Fast transient response with high-bandwidth control loop enabling tight output regulation for 4.5V point-of-load rails
- Compact 16-pin QFN package minimizing PCB footprint in multi-rail server and telecom power distribution designs
Applications
The LM27402SQ is optimized for point-of-load DC-DC conversion in server motherboards and telecom line cards where the 12V input bus must be regulated down to 4.5V or lower rails with high efficiency. Its voltage-mode PWM architecture with DCR current sensing eliminates the power loss of a series sense resistor while maintaining accurate overcurrent protection in high-current output stages. The 16-pin QFN package suits compact industrial power modules and programmable logic supply rails requiring tight transient regulation under step-load conditions.
Specifications
| YTEOL | 0 |
| Analog IC - Other Type | SWITCHING CONTROLLER |
| Control Mode | VOLTAGE-MODE |
| Control Technique | PULSE WIDTH MODULATION |
| Input Voltage-Max | 20V |
| Input Voltage-Min | 3V |
| Input Voltage-Nom | 12V |
| JESD-30 Code | S-XQCC-N16 |
| Number of Functions | 1 |
| Output Voltage-Nom | 4.5V |
| Package Body Material | UNSPECIFIED |
| Package Shape | SQUARE |
| Package Style | CHIP CARRIER, HEAT SINK/SLUG, VERY THIN PROFILE |
| Qualification Status | Not Qualified |
| Screening Level | TS 16949 |
| Surface Mount | YES |
| Switcher Configuration | BUCK |
| Switching Frequency-Max | 1350kHz |
| Technology | BICMOS |
| Temperature Grade | AUTOMOTIVE |
| Terminal Form | NO LEAD |
| Terminal Pitch | 0.65mm |
| Terminal Position | QUAD |
| Package | Quad Flat No-Lead |
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
| ECCN | EAR99 |
| HTS Code | 8542.39.00.60 |
Alternate & Equivalent Parts
Compatible alternatives and drop-in replacements for LM27402SQ:
Switching Controller, Voltage-mode, 30A, 1200kHz Switching Freq-Max, BICMOS
Frequently Asked Questions
What is the input voltage range of LM27402SQ and which common power bus standards does it directly support?
The LM27402SQ accepts input voltages from 3V to 20V with a nominal 12V design point, directly supporting the standard 12V server ATX rail, 12V telecom bus, and 5V USB power inputs without an additional pre-regulator. This range covers point-of-load conversion for FPGAs, ASICs, and DDR memory requiring sub-5V core voltages in data center and industrial equipment.
How does DCR current sensing in LM27402SQ improve efficiency compared to resistor-based sensing?
DCR sensing uses the inherent DC resistance of the output inductor, typically 1 mΩ to 10 mΩ, instead of a discrete sense resistor that would dissipate additional power proportional to I²R. At 10A output current with a 5 mΩ sense resistor, resistive sensing wastes 500 mW; DCR sensing recovers this loss, improving overall converter efficiency by 0.5% to 1% at full load.
For a 12V to 1.8V conversion at 15A load, what makes LM27402SQ suitable versus a simple integrated switch solution?
At 15A output, a controller paired with external MOSFETs allows selection of low-Rds(on) switches optimized for the specific voltage conversion ratio and switching frequency, while integrated switchers are limited to their fixed internal FETs. LM27402SQ's voltage-mode PWM and fast error amplifier maintain output ripple below 20 mV even during 5A step-load transients at 300 kHz switching frequency, meeting strict FPGA core voltage specifications.
What PCB area does the 16-pin QFN package of LM27402SQ require, and how does this compare to SOIC alternatives?
The 16-pin QFN package occupies approximately 4 mm x 4 mm of PCB area with exposed pad for thermal dissipation, compared to approximately 10 mm x 4 mm for an equivalent SOIC-16. This 60% area reduction enables multi-phase or multi-rail power designs on compact server blades and industrial control boards where power density exceeds 50W per square inch.
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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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