LTC7817 Series

40V, Low IQ, 3MHz, Triple Output Buck/Buck/Boost Synchronous Controller

Catalog

40V, Low IQ, 3MHz, Triple Output Buck/Buck/Boost Synchronous Controller

Part	Package / Case	Output Phases	Control Features	Duty Cycle (Max) [Max]	Output Type	Mounting Type	Function	Number of Outputs	Operating Temperature [Min]	Operating Temperature [Max]	Output Configuration	Frequency - Switching [Max]	Frequency - Switching [Min]	Voltage - Supply (Vcc/Vdd) [Max]	Voltage - Supply (Vcc/Vdd) [Min]	Topology
Analog Devices LTC7817IUHF#WTRPBF	38-WFQFN Exposed Pad	2	Current Limit Enable Frequency Control	100 %	Transistor Driver	Surface Mount	Step-Down Step-Up	3	-40 °C	125 ¯C	Positive	3 MHz	100 kHz	40 V	4.5 V	Boost Buck
Analog Devices LTC7817JUHF#WPBF	38-WFQFN Exposed Pad	2	Current Limit Enable Frequency Control	100 %	Transistor Driver	Surface Mount	Step-Down Step-Up	3	-40 °C	150 °C	Positive	3 MHz	100 kHz	40 V	4.5 V	Boost Buck
Analog Devices LTC7817EUHF#PBF	38-WFQFN Exposed Pad	2	Current Limit Enable Frequency Control	100 %	Transistor Driver	Surface Mount	Step-Down Step-Up	3	-40 °C	125 ¯C	Positive	3 MHz	100 kHz	40 V	4.5 V	Boost Buck
Analog Devices LTC7817JUHF#WTRPBF	38-WFQFN Exposed Pad	2	Current Limit Enable Frequency Control	100 %	Transistor Driver	Surface Mount	Step-Down Step-Up	3	-40 °C	150 °C	Positive	3 MHz	100 kHz	40 V	4.5 V	Boost Buck
Analog Devices LTC7817IUHF#WPBF	38-WFQFN Exposed Pad	2	Current Limit Enable Frequency Control	100 %	Transistor Driver	Surface Mount	Step-Down Step-Up	3	-40 °C	125 ¯C	Positive	3 MHz	100 kHz	40 V	4.5 V	Boost Buck

Catalog

40V, Low IQ, 3MHz, Triple Output Buck/Buck/Boost Synchronous Controller

Key Features

• Dual Buck Plus Single Boost Synchronous Controllers

• Low Operating IQ:

• 14μA (14V to 3.3V, Channel 1 On)

• Outputs Remain in Regulation Through Cold Crank Down to 1V Input Supply Voltage

• Wide Bias Input Voltage Range: 4.5V to 40V

• Buck and Boost Output Voltages up to 40V

• Pass-Thru™Operation: 100% Duty Cycle for Boost Synchronous MOSFET

• RSENSEor DCR Current Sensing

• Programmable Fixed Frequency (100kHz to 3MHz)

• Phase-Lockable Frequency (100kHz to 3MHz)

• Selectable Continuous, Pulse-Skipping, or Low Ripple Burst Mode Operation at Light Loads

• Very Low Buck Dropout Operation: 99% Duty Cycle

• Low Shutdown IQ: 1.5μA

• Small 38-Lead 5mm × 7mm QFN Package

• AEC-Q100 Qualified for Automotive Applications

Description

The LTC7817 is a high performance triple output (buck/buck/boost) synchronous DC/DC switching regulator controller that drives all N-channel power MOSFET stages. Its constant frequency current mode architecture allows a phase-lockable switching frequency of up to 3MHz. The LTC7817 operates from a wide 4.5V to 40V input supply range. When biased from the output of the boost converter or another auxiliary supply, the LTC7817 can operate from an input supply as low as 1V after start-up.The very low no-load quiescent current extends operating run time in battery powered systems. OPTI-LOOP®compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values. The LTC7817 features a precision 0.8V reference for the bucks, 1.2V reference for the boost and a power good output indicator.The LTC7817 synchronous boost Pass-Thru capability minimizes losses in automotive start-stop applications.APPLICATIONSAutomotive and TransportationIndustrialMilitary/Avionics