LTC3521IUF#PBF, Switching Voltage Regulators 1A Buck-Boost DC/DC and Dual 600mA Buck DC/DC Converters

LTC®3521 combines a 1A buck-boost DC/DC converter and a dual 600mA synchronous buck DC/DC converter. The 1.1MHz switching frequency minimizes the solution footprint while maintaining high efficiency. The buck converter is current mode controlled and utilize an internal synchronous rectifier to improve efficiency. The buck converter supports 100% duty cycle operation to extend battery life. If the PWM pin is held low, the buck converter automatically transition from burst mode operation to PWM mode at high loads. The buck-boost converter features continuous conduction operation to maximize efficiency and minimize noise. With the PWM pin held high, the buck converters remain in low noise, 1.1MHz PWM mode. Application includes bar code readers, medical instruments, handy terminals, PDAs, handheld PCs, GPS receivers.

• Pin-selectable burst mode® operation
• 30µA total quiescent current in burst mode operation, <2µA current in shutdown
• Independent power good indicator outputs, integrated soft-start
• Input voltage range from 1.8 to 5.5V (TA = 25°C)
• Typical burst mode quiescent current is 30µA (VFB1 = 0.66V, VFB2 = 0.66V, VFB3 = 0.66V, VPWM = 0V)
• Typical power good outputs low voltage is 0.1V (IPGOOD1 = IPGOOD2 = IPGOOD3 = 1mA, TA = 25°C)
• Typical oscillator frequency is 1.1MHz (TA = 25°C)
• Minimum duty cycle is 0% (VFB2 = VFB3 = 0.66V, TA = 25°C)
• 24-lead plastic QFN package
• Temperature rating range from -40°C to 125°C