ISL78228ARZ-T7A Renesas

DATASHEET ISL78228 FN7849 Rev 4.00 Dual 800mA Low Quiescent Current 2.25MHz High Efficiency Synchronous Buck February 26, 2016 Regulator The ISL78228 is a high efficiency, dual synchronous step-down Features DC/DC regulator that can deliver up to 800mA continuous Internal current mode compensation output current per channel. The supply voltage range of 2.75V to 5.5V allows for the use of a 3.3V or 5V input. The current 100% maximum duty cycle for lowest dropout mode control architecture enables very low duty cycle Selectable forced PWM mode and PFM mode operation at high frequency with fast transient response and External synchronization up to 4MHz excellent loop stability. The ISL78228 operates above the AM radio band as well as the 2.25MHz switching frequency, Start-up with prebiased output allowing for the use of small, low cost inductors and Soft-stop output discharge during disable capacitors. Each channel is optimized for generating an output voltage as low as 0.6V. Internal digital soft-start - 2ms Power-good (PG) output with 1ms delay The ISL78228 has a user configurable mode of operation-forced PWM mode and PFM mode. The forced PWM AEC-Q100 qualified mode operation reduces noise and RF interference while the Pb-free (RoHS compliant) PFM mode operation provides high efficiency by reducing switching losses at light loads. In PFM mode of operation, both Applications channels draw a total quiescent current of only 30A, hence DC/DC POL modules enabling high light-load efficiency in order to maximize battery life. C/P, FPGA and DSP power The ISL78228 offers a 1ms power-good (PG) to monitor both Rear camera systems outputs at power-up. When shut down, ISL78228 discharges Navigation systems the output capacitor. Other features include internal digital Infotainment systems soft-start, enable for power sequence, overcurrent protection, and thermal shutdown. The ISL78228 is offered in a 3mmx3mm 10 Ld DFN package with 1mm maximum height. TABLE 1. KEY DIFFERENCES BETWEEN FAMILY OF PARTS 2 The complete converter occupies less than 1.8cm area. PART I CH1 I CH2 ADJ or FIXED OUT OUT The ISL78228 is AEC-Q100 qualified and is rated for the NUMBER (A) (A) V PACKAGE OUT automotive temperature range (-40C to +105C). ISL78228 0.8 0.8 ADJ 10 Ld 3x3 DFN ISL78322 2.0 1.7 ADJ 12 Ld 4x3 DFN 100 90 80 2.5V -PFM OUT 1.8V -PFM OUT 70 2.5V -PWM OUT 60 1.8V -PWM OUT 50 VIN = 5V 40 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 OUTPUT LOAD (A) FIGURE 1. EFFICIENCY CHARACTERISTICS CURVE FN7849 Rev 4.00 Page 1 of 18 February 26, 2016 EFFICIENCY (%)ISL78228 Typical Application L1 OUTPUT1 2.2H 2.5V/800mA LX1 C2 10F C3 10pF PGND R2 316k INPUT 2.75V TO 5.5V FB1 VIN R3 EN1 C1 100k 10F ISL78228 EN2 L2 OUTPUT2 2.2H 1.8V/800mA LX2 PG C4 10F C5 10pF PGND R5 SYNC 200k FB2 R6 100k PGND FIGURE 2. TYPICAL APPLICATION FN7849 Rev 4.00 Page 2 of 18 February 26, 2016