Analog Devices Inc. LTC781x Synchronous Boost Buck Controllers

Analog Devices Inc. LTC781x Synchronous Boost Buck Controllers are high-performance, low quiescent current 38V and 60V DC-DC switching regulator controllers. The LTC781x Controllers drive the N-channel power MOSFET stages. The design includes independent step-up (boost) and step-down (buck) controllers. These independent boost and buck controllers can regulate two separate outputs. When cascaded, the independent boost and buck controllers regulate the output voltage from the input voltage. The input voltage can be above, below, or equal to the output voltage.

LTC781x's cascaded boost-buck solution delivers a fast transient response using continuous, non-pulsating input and output currents. The continuous, non-pulsating, input and output currents substantially reduce voltage ripple and EMI. LTC781x's low voltage ripple and reduced EMI make the controllers ideal for industrial, automotive, and high-power, battery-operated systems. The Analog Devices Inc. LTC781x Controllers operate from a 4.5V to 60V input supply and can maintain performance down to 2.2V after start-up. The controllers extend the operating run time in battery-powered systems with no-load quiescent current as low as 33µA.

Features

Synchronous boost and buck controllers
When cascaded, allows V_IN above, below, or equal to regulated V_OUT
Output remains in regulation through input dips (e.g., Cold Crank) down to 2.2V
4.5V to 60V bias input voltage range
Low input and output ripple
Low EMI
Fast output transient response
High light load efficiency
Low Operating I_Q
- 33μA operating I_Q(both channels on) (LTC7812)
- 28μA operating I_Q (buck channel on) (LTC7812)
- 29μA operating I_Q (one channel on) (LTC7813)
- 34μA operating I_Q (both channels on) (LTC7813)

R_SENSE or lossless DCR current sensing
Buck Output Voltage Range
- 0.8V ≤ V_OUT ≤ 24V (LTC7812)
- 0.8V ≤ V_OUT ≤ 60V (LTC7813)
Up to 60V boost output voltage
Phase-lockable frequency (75kHz to 850kHz)
Small 32-pin 5mm × 5mm QFN package