LT3692 Monolithic Dual Channel Tracking Step-Down Switching Regulator

describe

^{The LT®3692} is a dual channel, current mode PWM step-down DC/DC converter with two internal 3.5A switches. Independent input voltage, shutdown, feedback, soft-start, current limit and comparator pins for each channel simplify complex power supply tracking and sequencing requirements.

To optimize efficiency and component size, both converters have a programmable maximum current limit and are synchronized to a common external clock input or a resistor-settable 250kHz to 2.25MHz fixed internal oscillator. The device provides a frequency divider for channel 1 to further optimize component size. A 180° phase relationship is maintained between channels at all frequencies, reducing voltage ripple and component size. A clock output is provided for synchronizing multiple regulators.

The minimum input-to-output voltage ratio is improved by allowing the switch to remain on for multiple clock cycles, turning off only when the boost capacitor needs to be recharged. Independent channel operation can be set using the SHDN pin. Disabling both converters reduces the total quiescent current to <10μA.

Features

Wide input range:

● Works from 3V to 36V

● OVLO (Over Voltage Lockout) function protects the circuit from 60V transient voltage

● Independent power supply, shutdown, soft-start, programmable current limit and programmable power good indicator pin for each 3.5A regulator

● Adjustable/synchronizable fixed frequency operation with synchronous clock output: 250kHz to 2.25MHz

● Independent synchronous switching frequency optimizes component size

● Reverse switching operation

● Output can be connected in parallel

● Flexible output voltage tracking

● Enhanced short circuit protection

● Low dropout voltage: 95% maximum duty cycle

● Low shutdown current: <10μA

● 5mm x 5mm QFN package

Encapsulation

Typical Applications

application

● Car power supply

Distributed power supply regulation