LT8619
LT8619-5

RECOMMENDED FOR NEW DESIGNS

60V, 1.2A Synchronous Monolithic Buck Regulator with 6μA Quiescent Current

Data Sheet (Rev. D) Product Selection Table
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Overview

  • Wide Input Voltage Range: 3V to 60V
  • Fast Minimum Switch-On Time: 30ns
  • Ultralow Quiescent Current Burst Mode Operation:
    • 6μA IQ Regulating 12VIN to 3.3VOUT
    • 10mVP-P Output Ripple at No Load
  • Synchronizable/Programmable Fixed Frequency Forced Continuous Mode Operation: 300kHz to 2.2MHz
  • Low Dropout: 360mV at 0.5A
  • Low EMI
  • High Efficiency Synchronous Operation:
    • 92% Efficiency at 0.5A, 5VOUT from 12VIN
    • 90% Efficiency at 0.5A, 3.3VOUT from 12VIN
  • Accurate 1V Enable Pin Threshold
  • Internal Soft-Start and Compensation
  • Power Good Flag
  • Small Thermally Enhanced 16-Lead MSOP Package and 10-Lead (3mm × 3mm) DFN Packages
  • AEC-Q100 Qualified for Automotive Applications
  • Enables Functional Safety on a System Level
LT8619
LT8619-5
60V, 1.2A Synchronous Monolithic Buck Regulator with 6μA Quiescent Current
LT8619/L8619-5 Application Circuit LT8619/L8619-5 Performance Graph LT8619/L8619-5 Pin Configuration LT8619/L8619-5 Pin Configuration
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Documentation

Data Sheet 1

Technical Articles 1

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Software Resources

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Hardware Ecosystem

Parts Product Life Cycle Description
Hot Swap Controllers 2
LTC4231
RECOMMENDED FOR NEW DESIGNS Micropower Hot Swap Controller
LTC4380
RECOMMENDED FOR NEW DESIGNS Low Quiescent Current Surge Stopper
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Tools & Simulations

LTspice 1

Models for the following parts are available in LTspice:

  • LT8619
  • LT8619-5

LTpowerCAD 1

Design tools for the following parts are available in LTpowerCAD:

  • LT8619
LTspice

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.

LTpowerCAD

LTpowerCAD® is a power supply design program which selects power stage components, provides detailed power efficiency, shows quick loop Bode plot stability and load transient analysis, and can export to LTspice for simulation.

Evaluation Kits

eval board
schematic 1
schematic 2
schematic 3
schematic 4
schematic 5
DC2137A

LT8619 60V, 1.2A Synchronous Monolithic Buck Regulator with 6µA Quiescent Current

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Product Details

Demonstration circuit 2137A is a monolithic step-down DC/DC switching regulator featuring the LT®8619. The LT8619 is a high efficiency, high speed synchronous monolithic step-down switching regulator that consumes only 6µA of quiescent current. The demo circuit is designed for 5V, 1.2A output from 6V to 48V input with the transient input voltage up to 60V. The wide input range makes it suitable for regulating power from a wide variety of sources, including automotive, industrial systems and telecom supplies. The power switch, compensation and other necessary circuits are inside of the LT8619 to minimize external components and simplify design.

The LT8619 switching frequency can be programmed either via oscillator resistor or external clock over a 300kHz to 2.2MHz range. The default frequency of demo circuit 2137A is 2MHz. The SYNC pin on the demo board is grounded (JP1 at BURST position) by default for low ripple Burst Mode® operation. To synchronize to an external clock, move JP1 to SYNC and apply the external clock to the SYNC terminal. The RT resistor (R4) should be chosen to set the LT8619 internal switching frequency equal or below the lowest synchronization input. During clock synchronization, the controller enters forced continuous mode. Pulse-skipping mode and forced continuous mode can be selected respectively by moving JP1 shunt.

Low ripple Burst Mode operation increases the efficiency at the light load while keeping the output ripple low. Figure 1 shows the efficiency of the circuit at 12V and 24V input in Burst Mode operation (input from VIN terminal to bypass the EMI filter).

The demo board has an EMI filter installed. The EMI performance of the board (with EMI filter) is shown on Figure 2. The red line in Radiated EMI Performance is CISPR25 Class 5 peak limit. The figure shows that the circuit passes the test with a wide margin. To achieve EMI/ EMC performance as shown in Figure 2, the input EMI filter is required and the input voltage should be applied at VEMI terminal.

The LT8619 data sheet gives a complete description of the part, operation and application information. The data sheet must be read in conjunction with this demo manual for demo circuit 2137A. The LT8619 is assembled in a small 16-lead MSOP and 10-lead 3mm × 3mm DFN packages with exposed pad. Proper board layout is essential for both low EMI operation and maximum thermal performance. See the data sheet sections for details.
DC2137A
LT8619 60V, 1.2A Synchronous Monolithic Buck Regulator with 6µA Quiescent Current
DC2137A DC2137A DC2137A DC2137A_UG-1297 Image DC2137A_UG-1297 Image

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