The LM2598 is a 150kHz 1A step-down switching regulator that provides fixed 3.3V, 5V, 12V, and an adjustable output voltage. This chip features excellent line and load regulation and only requires the minimum number of external components for use.
The LM2598 series is a monolithic integrated circuit that provides all active functions for a step‑down (buck) switching regulator. It drives a 1 A load, offers excellent line and load regulation, and operates at a fixed 150 kHz switching frequency, allowing smaller filter components.
The device is available in fixed 3.3 V, 5 V, and 12 V versions as well as an adjustable version (1.2 V‑37 V). It comes in 7‑lead TO‑220 and TO‑263 packages, includes shutdown/soft‑start, error‑flag functions, and internal frequency compensation. Typical applications include high‑efficiency buck regulators, pre‑regulators for linear regulators, and on‑card switching supplies.
| Fixed output voltages | 3.3 V, 5 V, 12 V |
|---|---|
| Adjustable output range | 1.2 V to 37 V |
| Maximum output current | 1 A |
| Switching frequency | 150 kHz |
| Input voltage range | 4.5 V to 40 V |
| Efficiency (12 V in, 1 A load) | ≈78 % |
The LM2598 can deliver up to 1 A of output current.
It operates with an input voltage from 4.5 V up to 40 V.
The regulator switches at a fixed frequency of 150 kHz.
No heat sink is required for output voltages less than 12 V and ambient temperatures below 50 °C.