ISL78235ARZ-T7A

The ISL78235ARZ-T7A is a highly efficient, monolithic, synchronous step-down DC/DC converter that can deliver 5A of continuous output current from a 2.7V to 5.5V input supply. The device uses peak current mode control architecture to achieve very low duty cycle operation at high frequency with fast transient response and excellent loop stability.

The ISL78235ARZ-T7A integrates a low ON-resistance P-channel (35mΩ, typical) high-side FET and N-channel (11mΩ, typical) low-side FET to maximize efficiency and minimize external component count. The 100% duty cycle operation allows less than 250mV dropout voltage at 5A output current. The operating 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 ISL78235ARZ-T7A can be configured for discontinuous (PFM) or forced continuous (PWM) operation at light load. Forced continuous operation reduces noise and RF interference; 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. The device also integrates output overvoltage and over-temperature protections. A power-good monitor indicates when the output is in regulation. The ISL78235ARZ-T7A features a 1ms Power-Good (PG) timer at power-up. When in shutdown, the ISL78235ARZ-T7A discharges the output capacitor through an internal 100Ω soft-stop switch. Other features include internal fixed or adjustable soft-start and internal/external compensation.

The ISL78235ARZ-T7A is available in a 3mm x 3mm 16 Ld Thin Quad Flat No-lead (TQFN) Pb-free package and in a 5mmx5mm 16 Ld Wettable Flank Quad Flat No-Lead (WFQFN) package with an exposed pad for improved thermal performance. The ISL78235ARZ-T7A is rated to operate across the temperature range of -40°C to +105°C in the 3mmx3mm package and -40°C to +125°C in the 5mmx5mm package.

Feature