LTC7897

RECOMMENDED FOR NEW DESIGNS

140V, Low IQ, Synchronous Buck Controller with Programmable 5V to 10V Gate Drive

Data Sheet (Rev. A) Product Selection Table

Part Models: 2
1ku List Price: Starting From $3.50

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Overview

Wide V_IN Range: 4V to 135V (140V ABS MAX)
Wide Output Voltage Range: 0.8V ≤ V_OUT ≤ 135V (140V ABS MAX)
Adjustable Gate Drive Level: 5V to 10V (OPTI-DRIVE, 14V ABS MAX)
Adjustable Driver Voltage UVLO
Adaptive or Resistor Adjustable Dead Times
Split-Output Gate Drivers for Adjustable Turn-On and Turn-Off Driver Strengths

100% Duty Cycle Operation
Low Operating I_Q: 5μA (48V<_IN to 3.3V_OUT)
Spread Spectrum Frequency Modulation
Programmable Frequency (100kHz to 2.5MHz);
Synchronizable Frequency (100kHz to 2.5MHz);
28-Pin (4mm x 5mm) QFN Package

The LTC^®7897 is a high performance, 100% duty cycle capable, synchronous step-down, DC/DC switching regulator controller that drives all N-channel synchronous silicon metal oxide field effect transistor (MOSFET) power stages. Synchronous rectification increases efficiency, reduces power loss, and simplifies the application design by reducing thermal requirements.

The wide input and output voltage ranges of the LTC7897 enable not only high step-down ratios but also a wide range of positive to negative voltage conversion. The gate drivers of the LTC7897 provide robustness with a 14V ABS MAX rating and flexibility with adjustable drive levels and dead times to optimize applications.

The gate drive voltage of the LTC7897 can optionally be adjusted from 5V to 10V to allow use of logic-level or standard threshold MOSFETs. The dead times of the LTC7897 can be optimized with external resistors for margin or to tailor the application for higher efficiency and allow for high frequency operation.

Applications

Industrial Power Systems
Military/Avionics
Telecommunications Power Systems

Part Models: 2
1ku List Price: Starting From $3.50

Documentation

Data Sheet 1

LTC7897: 140V, Low IQ, Synchronous Buck Controller with Programmable 5V to 10V Gate Drive Data Sheet (Rev.A) 03/04/2025

User Guide 1

EVAL-LTC7897-AZ User Guide: Wide Input and Output Voltage Synchronous Buck Controller (Rev.0) 03/04/2025

ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal. View our quality and reliability program and certifications for more information.

Part Model	Pin/Package Drawing	Documentation	CAD Symbols, Footprints, and 3D Models
LTC7897RUFD#PBF	28-Lead QFN (4mm x 5mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC7897RUFD#TRPBF	28-Lead QFN (4mm x 5mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys

Part Models	Product Lifecycle	PCN

Aug 11, 2025 - 25_0123 LTC7897 Data Sheet Revision
		PCN25_0123_Form Material_Report Datasheet Specification Comparison
LTC7897RUFD#PBF	PRODUCTION
LTC7897RUFD#TRPBF	PRODUCTION

This is the most up-to-date revision of the Data Sheet.

Software Resources

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Tools & Simulations

LTspice 1

135V Synchronous Buck Converter, Input: 16V - 135V, Output: 12V @ 20A, Fsw: 200kHz

LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.

Evaluation Kits

Wide Input and Output Voltage Synchronous Buck Controller

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Product Details

The evaluation circuit EVAL-LTC7897-AZ features the LTC^®7897: a 140V Low I_Q Synchronous Buck Controller with Programmable 5V to 10V Gate Drive. Split gate drivers allow for easily adjustable turn-on and turn-off of FETs. User adjustable adaptive and smart dead time control modes are available for optimal gate timing. Additionally, the IC features low I_Q, up to 2.5MHz programmable/synchronizable switching frequency, spread spectrum, and a small 28-lead (4mm x 5mm) QFN package. These features allow for a wide variety of applications including industrial, military, medical, and telecommunications systems.

The EVAL-LTC7897-AZ operates from a 16V to 100V input voltage range and generates a 12V, 20A output (see Figure 8 in user guide). The LTC7897 has a precision voltage reference providing an output voltage with 2% tolerance over the full operating conditions. The EVAL-LTC7897-AZ is set to a 200kHz switching frequency, which results in a small and efficient circuit. The converter achieves over 93% efficiency with a 20A load at full operating V_IN and peak efficiency over 96%.

The LTC7897 supports output voltages from 0.8V to 135V. The evaluation circuit has been designed with 150V FETs. Various FETs of similar footprint can be substituted to fit a wide array of applications.

The EVAL-LTC7897-AZ provides a high-performance, cost-effective solution for generating a 12V output. The LTC7897 data sheet gives a complete description of this part, its operation, and application information. The data sheet must be read in conjunction with this user guide for EVAL-LTC7897-AZ.

Design files for this circuit board are available at www.analog.com.