Overview: DATASHEET ISL78233, ISL78234
3A and 4A pact Synchronous Buck Regulators FN8359 Rev.11.01 Jun 16, 2022 The ISL78233 and ISL78234 are highly efficient, monolithic, synchronous step-down DC/DC converters that can deliver 3A (ISL78233), or 4A (ISL78234) of continuous output current from a 2.7V to 5.5V input supply. The devices use current mode control architecture to deliver a very low duty cycle operation at high frequency with fast transient response and excellent loop stability.
The ISL78233 and ISL78234 integrate a very low ON-resistance P-channel (35mΩ) high-side FET and N-channel (11mΩ) low-side FET to maximize efficiency and minimize external ponent count. The 100% duty-cycle operation allows less than 200mV dropout voltage at 4A output current. The operation frequency of the Pulse-Width Modulator (PWM) is adjustable from 500kHz to 4MHz. The default switching frequency of 2MHz is set by connecting the FS pin high.
The ISL78233 and ISL78234 can be configured for discontinuous or forced continuous operation at light load. Forced continuous operation reduces noise and RF interference, while discontinuous mode provides higher efficiency by reducing switching losses at light loads.
Fault protection is provided by internal Hiccup mode current limiting during short-circuit and overcurrent conditions. Other protection, such as overvoltage and over-temperature are also integrated into the device. A power-good output voltage monitor indicates when the output is in regulation.
The ISL78233 and ISL78234 offer a 1ms Power-Good (PG) timer at power-up. When in shutdown, the ISL78233 and ISL78234 discharge the output capacitor through an internal soft-stop switch.
