LTC7871

Part: LTC7871 — Analog Devices

Type: Six-Phase, Synchronous Bidirectional Buck or Boost Controller

Description: The LTC7871 is a high performance six-phase bidirectional buck or boost switching regulator controller that operates from V HIGH voltages up to 100V and V LOW voltages up to 60V, featuring ±1% voltage regulation accuracy and an SPI compliant serial interface. It allows dynamic regulation of input voltage, output voltage, or current.

Operating Conditions:

• Supply voltage: V HIGH: 6–100 V, V LOW: 1.2–60 V
• Operating temperature: -40 to 150 °C
• Switching frequency: 60 kHz to 750 kHz

Absolute Maximum Ratings:

• Max supply voltage: V HIGH: 100 V
• Max continuous current: DRV CC /EXTV CC Peak Current: 150 mA
• Max junction/storage temperature: 150 °C

Key Specs:

• V HIGH Supply Voltage Range: 6 V to 100 V
• V LOW Supply Voltage Range: 1.2 V to 60 V
• V LOW Regulated Feedback Voltage: 1.188 V to 1.212 V (l, ITH LOW Voltage = 1.5V)
• V HIGH Regulated Feedback Voltage: 1.188 V to 1.212 V (l, ITH HIGH Voltage = 0.5V)
• Synchronous Rectification Efficiency: Up to 98%
• Synchronizable Frequency: 60 kHz to 750 kHz (l, SYNC = External Clock)
• Maximum Current Sense Threshold (R SENSE Configuration): 12.5 mV (Typ, V ILIM = 0V)
• Buck Mode Maximum Duty Cycle: 98%

Features:

• Unique Architecture Allows Dynamic Regulation of Input Voltage, Output Voltage or Current
• Operates with External Gate Drivers and MOSFETs
• Synchronous Rectification: Up to 98% Efficiency
• ±1% Voltage Regulation Accuracy Overtemperature
• SPI Compliant Serial Interface
• Multiphase/Multi-ICs Operation Up to 24 Phases

Applications:

• Automotive 48V/12V Dual Battery Systems
• Backup Power Systems

Package:

• 64-Lead (10mm × 10mm) Plastic LQFP

• n Unique Architecture Allows Dynamic Regulation of Input Voltage, Output Voltage or Current
• n Operates with External Gate Drivers and MOSFETs
• n VHIGH Voltages Up to 100V; V LOW Voltages Up to 60V
• n Synchronous Rectification: Up to 98% Efficiency
• n ADI-Proprietary Advanced Current Mode Control
• n ±1% Voltage Regulation Accuracy Overtemperature
• n Accurate, Programmable Inductor Current Monitoring and Bidirectional Regulation
• n SPI Compliant Serial Interface
• n Operation Status and Fault Report
• n Programmable V HIGH , V LOW Margining
• n Phase-Lockable Frequency: 60kHz to 750kHz
• n Optional Spread Spectrum Modulation
• n Multiphase/Multi-ICs Operation Up to 24 Phases
• n Selectable CCM/DCM/Burst Mode Operation
• n Thermally Enhanced 64-Lead LQFP Package
• n AEC-Q100 Qualification in Progress

• n Automotive 48V/12V Dual Battery Systems
• n Backup Power Systems

Rev. B

ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T A = 25°C, V HIGH = 48V, V RUN = 5V unless otherwise noted. (Note 2)

Rev. B

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Rev. B

ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T A = 25°C, V HIGH = 48V, V RUN = 5V unless otherwise noted. (Note 2)

V

The LTC7871 has a temperature sensor integrated on the IC, to sense the die temperature. When the die temperature exceeds 180°C, all switching actions stop, and all PWM pins become Hi-Z, thus turning off all external MOSFETs. At the same time, all the channels are disconnected from the IMON pins, and the SS and ITH HIGH / ITH LOW pins continue to function normally, so as not to interfere with other LTC7871 chips that may reference the common pins. When the temperature drops 15°C below the trip threshold, normal operation resumes.

The Typical Application on the first page of this data sheet is a basic LTC7871 application circuit. In general, external component selection is driven by the load requirements, and begins with the DCR or R SENSE and inductor value. Next, power MOSFETs are selected. Finally, V HIGH and VLOW capacitors are selected.

High Voltage Bidirectional Controller with Programming and Monitoring Functions