Features

• Programmable Average Input Current Limit: ±5% Accuracy
• Dual Step-Down Outputs: Up to 96% Efficiency
• Low Ripple (<25mV_P-P) Burst Mode® Operation: I_Q = 50μA
• Input Voltage Range: 2.5V to 5.5V
• Output Voltage Range: 0.6V to 5V
• 2.25MHz Constant-Frequency Operation
• Power Good Output Voltage Monitor for Each Channel
• Low Dropout Operation: 100% Duty Cycle
• Independent Internal Soft-Start for Each Channel
• Current Mode Operation for Excellent Line and Load Transient Response
• ±2% Output Voltage Accuracy
• Short-Circuit Protected
• Shutdown Current ≤ 1μA
• Available in Small Thermally Enhanced 10-Lead MSE and 3mm × 3mm DFN Packages

Typical Application

Description

The LTC3619 is a dual monolithic synchronous buck regulator using a constant frequency, current mode architecture.

The input supply voltage range is 2.5V to 5.5V, making it ideal for Li-Ion and USB powered applications. 100% duty cycle capability provides low dropout operation, extending the run time in battery-operated systems. Low output voltages are supported with the 0.6V feedback reference voltage. Channel 1 and channel 2 can supply 400mA and 800mA output current, respectively.

The LTC3619’s programmable average input current limit is ideal for USB applications and for point-of-load power supplies because the LTC3619’s limited input current will still allow its output to deliver high peak load currents without collapsing the input supply. When the sum of both channels’ currents exceeds the input current limit, channel 2 is current limited while channel 1 remains regulated. The operating frequency is internally set at 2.25MHz allowing the use of small surface mount inductors. Internal soft-start reduces in-rush current during start-up. The LTC3619 is available in small MSOP and 3mm × 3mm DFN packages and is also available in a low noise, high efficiency pulse skipping version, LTC3619B.