LM21305SQE/NOPB
Active3-18V, 5A, CURRENT MODE SYNCHRONOUS BUCK REGULATOR WITH ADJUSTABLE FREQUENCY
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LM21305SQE/NOPB
Active3-18V, 5A, CURRENT MODE SYNCHRONOUS BUCK REGULATOR WITH ADJUSTABLE FREQUENCY
Technical Specifications
Parameters and characteristics for this part
| Specification | LM21305SQE/NOPB |
|---|---|
| Current - Output | 5 A |
| Frequency - Switching [Max] | 1.5 MHz |
| Frequency - Switching [Min] | 300 kHz |
| Function | Step-Down |
| Mounting Type | Surface Mount |
| Number of Outputs | 1 |
| Operating Temperature [Max] | 85 °C |
| Operating Temperature [Min] | -40 °C |
| Output Configuration | Positive |
| Output Type | Adjustable |
| Package / Case | 28-WFQFN Exposed Pad |
| Supplier Device Package | 28-WQFN (5x5) |
| Synchronous Rectifier | True |
| Topology | Buck |
| Voltage - Input (Max) [Max] | 18 V |
| Voltage - Input (Min) [Min] | 3 V |
| Voltage - Output (Max) [Max] | 18 V |
| Voltage - Output (Min/Fixed) | 0.598 V |
Pricing
Prices provided here are for design reference only. For realtime values and availability, please visit the distributors directly
| Distributor | Package | Quantity | $ | |
|---|---|---|---|---|
| Digikey | Cut Tape (CT) | 1 | $ 7.68 | |
| 10 | $ 6.94 | |||
| 25 | $ 6.61 | |||
| 100 | $ 5.74 | |||
| Digi-Reel® | 1 | $ 7.68 | ||
| 10 | $ 6.94 | |||
| 25 | $ 6.61 | |||
| 100 | $ 5.74 | |||
| Tape & Reel (TR) | 250 | $ 5.48 | ||
| 500 | $ 5.00 | |||
| 1250 | $ 4.36 | |||
| Texas Instruments | SMALL T&R | 1 | $ 5.88 | |
| 100 | $ 4.79 | |||
| 250 | $ 3.77 | |||
| 1000 | $ 3.19 | |||
Description
General part information
LM21305 Series
The LM21305 is a full-featured, 5-A, synchronous buck dc-dc converter optimized for solution size, flexibility, and high conversion efficiency. High-power density LM21305 designs are easily achieved by virtue of monolithic integration of high-side and low-side power MOSFETs, high switching frequency, peak current-mode control, and optimized thermal design. The efficiency of the LM21305 is maximized at light loads with diode emulation mode operation and at heavy loads by optimal design of the MOSFET adaptive gate drivers to minimize switch dead-times and body-diode conduction losses.
The LM21305 accepts a wide input voltage range of 3 V to 18 V for interface to various intermediate bus voltages, including 3.3-V, 5-V, and 12-V rails. A 1.5% voltage reference and 70-ns, high-side MOSFET minimum controllable on-time enable output voltages as low as 0.598 V with excellent setpoint accuracy. The LM21305 is available in a 5-mm × 5-mm2WQFN-28 thermally-enhanced package with 0.5-mm pitch.
The LM21305 offers flexible system configuration with programmable switching frequency from 300 kHz to 1.5 MHz using one resistor or by external clock synchronization for beat-frequency-sensitive and multi-regulator applications. On-chip bias supply low-dropout (LDO) sub-regulators eliminate the need for an external bias power and simplify circuit board layout. The device also offers an internal soft-start to limit inrush current and provide monotonic startup capability into unbiased and pre-biased loads, integrated boot diodes, cycle-by-cycle current limiting, and thermal shutdown. Peak current-mode control with a high-gain error amplifier maintains stability throughout the entire input voltage and load current ranges, enabling excellent line and load transient response.
Documents
Technical documentation and resources