LTC7821
Info : RECOMMENDED FOR NEW DESIGNS
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LTC7821

Hybrid Step-Down Synchronous Controller

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Info : RECOMMENDED FOR NEW DESIGNS tooltip
Info : RECOMMENDED FOR NEW DESIGNS tooltip
Part Details
Part Models 4
1ku List Price Starting From $6.20
Features
  • Wide VIN Range: 10V to 72V (80V ABS Max)
  • Soft Switching for Low Noise Operation
  • Phase-Lockable Fixed Frequency 200kHz to 1.5MHz
  • ±1% Output Voltage Accuracy
  • RSENSE or DCR Current Sensing
  • Programmable CCM, DCM, or Burst Mode® Operation
  • CLKOUT Pin for Multiphase Operation
  • Short Circuit Protected
  • EXTVCC Input for Improved Efficiency
  • Monotonic Output Voltage Start-Up
  • Optional External Reference
  • 32-Pin (5mm × 5mm) QFN
Additional Details
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The LTC7821 uses a proprietary architecture that merges a soft switching charge pump topology with a synchronous step-down converter to provide superior efficiency and EMI performance compared to traditional switching architectures.

In a typical 48V to 12V application, efficiency of greater than 97% is attainable with the LTC7821 switching at 500kHz. The same efficiency can only be achieved with a traditional controller switching at one-third the frequency. Higher switching frequencies allow the use of smaller inductances that yield faster transient response and smaller solution size.

The LTC7821 can be easily paralleled to provide higher output currents with its accurate current sharing capability and frequency synchronization function.

Applications

  • Intermediate Bus Converters
  • High Current Distributed Power Systems
  • Telecom, Datacom, and Storage Systems
Part Models 4
1ku List Price Starting From $6.20

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Documentation

Documentation

Video

Part Model Pin/Package Drawing Documentation CAD Symbols, Footprints, and 3D Models
LTC7821EUH#PBF
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LTC7821EUH#TRPBF
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LTC7821IUH#PBF
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Product Lifecycle

PCN

Jan 20, 2022

- 21_0269

Addition of Alternate Assembly Site ASE Taiwan for Select LFCSP Products

LTC7821EUH#PBF

PRODUCTION

LTC7821EUH#TRPBF

PRODUCTION

LTC7821IUH#PBF

PRODUCTION

LTC7821IUH#TRPBF

PRODUCTION

Jun 30, 2021

- 21_0130

LTC7821 Die Revision

LTC7821EUH#PBF

PRODUCTION

LTC7821EUH#TRPBF

PRODUCTION

LTC7821IUH#PBF

PRODUCTION

LTC7821IUH#TRPBF

PRODUCTION

Aug 27, 2020

- 20_0272

Additional Wafer Fab Location (Vanguard International Semiconductor, Taiwan) for LTC2949 and LTC7821

LTC7821EUH#PBF

PRODUCTION

LTC7821EUH#TRPBF

PRODUCTION

LTC7821IUH#PBF

PRODUCTION

LTC7821IUH#TRPBF

PRODUCTION

Filter by Model

reset

Reset Filters

Part Models

Product Lifecycle

PCN

Jan 20, 2022

- 21_0269

arrow down

Addition of Alternate Assembly Site ASE Taiwan for Select LFCSP Products

LTC7821EUH#PBF

PRODUCTION

LTC7821EUH#TRPBF

PRODUCTION

LTC7821IUH#PBF

PRODUCTION

LTC7821IUH#TRPBF

PRODUCTION

Jun 30, 2021

- 21_0130

arrow down

LTC7821 Die Revision

LTC7821EUH#PBF

PRODUCTION

LTC7821EUH#TRPBF

PRODUCTION

LTC7821IUH#PBF

PRODUCTION

LTC7821IUH#TRPBF

PRODUCTION

Aug 27, 2020

- 20_0272

arrow down

Additional Wafer Fab Location (Vanguard International Semiconductor, Taiwan) for LTC2949 and LTC7821

LTC7821EUH#PBF

PRODUCTION

LTC7821EUH#TRPBF

PRODUCTION

LTC7821IUH#PBF

PRODUCTION

LTC7821IUH#TRPBF

PRODUCTION

Software & Part Ecosystem

Software & Part Ecosystem

Evaluation Kit

Evaluation Kits 3

reference details image

DC2513A

OBSOLETE: LTC7821EUH Demo Board | 36V ≤ VIN ≤ 72V; VOUT = 12V at 20A, 97.5% Efficiency/500kHz

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DC2513A

OBSOLETE: LTC7821EUH Demo Board | 36V ≤ VIN ≤ 72V; VOUT = 12V at 20A, 97.5% Efficiency/500kHz

OBSOLETE: LTC7821EUH Demo Board | 36V ≤ VIN ≤ 72V; VOUT = 12V at 20A, 97.5% Efficiency/500kHz

Product Detail

This evaluation board is obsolete and no longer recommended.  The replacement board is the DC2513B.

Demonstration circuit 2513A is a high efficiency, high power density hybrid converter. It can deliver 12V/20A with an input voltage from 36V to 72V. This demo board features the LTC7821, which uses an architecture that merges soft-switching switched-capacitor topology with a traditional step-down converter to provide superior efficiency compared to the traditional switching architectures. It offers a high efficiency/high density and cost effective solution for non isolated intermediate bus applications in power distribution, datacom and telecom as well as emerging 48V automotive systems.

reference details image

DC2513B

LTC7821 Demo Board | 12V, 20A Hybrid Step-Down Synchronous Converter

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DC2513B

LTC7821 Demo Board | 12V, 20A Hybrid Step-Down Synchronous Converter

LTC7821 Demo Board | 12V, 20A Hybrid Step-Down Synchronous Converter

Product Detail

Demonstration circuit 2513B is a high efficiency, high power density hybrid converter. It can deliver 12V/20A with an input voltage from 36V to 72V. This demo board features the LTC7821, which uses an architecture that merges soft-switching switched-capacitor topology with a traditional step-down converter to provide superior efficiency compared to the traditional switching architectures. It offers a high efficiency/high density and cost effective solution for nonisolated intermediate bus applications in power distribution, datacom and telecom as well as emerging 48V automotive systems.

External MOSFETs switch at a 500kHz fixed frequency for this demo board and can be programmed from 200kHz to 1.5MHz. The LTC7821’s powerful 1Ω N-channel MOSFET gate drivers maximize efficiency and can drive multiple MOSFETs in parallel for higher power applications. Due to its current mode control architecture, multiple LTC7821s can be operated in a parallel, multiphase configuration with excellent current sharing and low output voltage ripple to enable much higher power applications. Other benefits include low EMI emissions due to a soft-switched front end and reduced MOSFET stress.

The LTC7821 design eliminates the inrush current typically associated with switched capacitor circuits by prebalancing the capacitors on start-up. The LTC7821 also monitors system voltage, current and temperature for faults, and uses a sense resistor for overcurrent protection. It stops switching and pulls the FAULT pin low when a fault condition occurs. An onboard timer can be set for appropriate restart/retry times.

Additional features include ±1% output voltage accuracy over temperature, a clock output for multiphase operation, a power good output signal, short-circuit protection, monotonic output voltage start-up, optional external reference, undervoltage lockout and internal charge balance circuitry.

The LTC7821 data sheet must be used in conjunction with this demo board manual.

reference details image

DC2787A

LTC7821 Demo Board | 40V ≥ VIN ≥ 60V, VOUT = 12V @ 100A

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DC2787A

LTC7821 Demo Board | 40V ≥ VIN ≥ 60V, VOUT = 12V @ 100A

LTC7821 Demo Board | 40V ≥ VIN ≥ 60V, VOUT = 12V @ 100A

Product Detail

Demonstration circuit 2787A is a high efficiency, 4 phase, hybrid converter. It can deliver 12V/100A with the input voltage from 40V to 60V. The demo board features the LTC7821, which uses an architecture that merges a soft-switching switched-capacitor topology with a traditional step-down converter to provide superior efficiency compared to the traditional switching architectures. It offers a high efficiency/high density and cost effective solution for nonisolated intermediate bus applications in power distribution, datacom and telecom as well as emerging 48V automotive systems. 

External MOSFETs switch at a 400kHz fixed frequency for this demo board and can be programmed from 200kHz to 1.5MHz. The LTC7821’s powerful 1Ω N-channel MOSFET gate drivers maximize efficiency and can drive multiple MOSFETs in parallel for higher power applications. Due to its current mode control architecture, multiple LTC7821 devices can be operated in a parallel, multiphase configuration with excellent current sharing and low output voltage ripple to enable much higher power applications. Other benefits include low EMI emissions due to a soft-switched front end and reduced MOSFET stress.

The LTC7821 design eliminates the inrush current typically associated with switched capacitor circuits by prebalancing the capacitors on start-up. The LTC7821 also monitors system voltage, current and temperature for faults, and uses a sense resistor for overcurrent protection. It stops switching and pulls the FAULT pin low when a fault condition occurs. An onboard timer can be set for appropriate restart/retry times. Additional features include ±1% output voltage accuracy over temperature, a clock output for multiphase operation, a power good output signal, short-circuit protection, monotonic output voltage start-up, optional external reference, undervoltage lockout and internal charge balance circuitry. The LTC7821 data sheet must be used in conjunction with this demo board manual.

Tools & Simulations

Tools & Simulations 1

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.

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