Features and Benefits
- Input Voltage Range: 2.5V to 26V
- 0.8V to 24V Output Voltage Range
- High Output Current
- 6.5A with VOUT = 5V, VIN > 6V
- 3A with VOUT = 5V, VIN = 3V
- 6.5A with VOUT = 12V, VIN > 14V
- 4 A with VOUT = 12V, VIN = 9V
- Ultralow Noise Buck-Boost Architecture
- Programmable Output Current Limit
- Programmable Frequency Range: 400kHz to 2MHz
- Accurate Enable Comparator Threshold
- Burst Mode® Operation, No-Load IQ = 35μA
- Current Mode Control
- External Clock Synchronization
- Maximum Power Point Control
- 28-Lead 4mm × 5mm LQFN Package
The LT3120 is a high efficiency 26V monolithic buck-boost converter. Extensive feature integration and very low resistance internal power switches minimize the total solution footprint for even the most demanding applications. A proprietary 4-switch PWM architecture provides seamless low noise operation from input voltages above, equal to, or below the output voltage.
External frequency programming as well as synchronization using an internal PLL enable operation over a wide switching frequency range of 400kHz to 2MHz. The wide 2.5V to 26V input range is well suited for operation from unregulated power sources including battery stacks and backup capacitors. After start-up, operation is possible with input voltages as low as 500mV.
Other features include, output short-circuit protection, thermal overload protection, less than 3μA shutdown current, power good indicator, Burst Mode operation, and maximum power point control.
The LT3120 is offered in thermally enhanced 28-lead 4mm × 5mm LQFN package.
- RF Power Supply
- USB Power Delivery
- System Backup Power Supply
- 1-Cell to 5-Cell Lithium Battery Powered Products
- Wide Input Range Power Supply
- Lead Acid to 12V Regulator
Product Lifecycle Recommended for New Designs
This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.
Evaluation Kits (1)
Demonstration circuit 2815A features the LT3120, as wide operating range synchronous monolithic buck-boost converter with programmable output current limit.
The DC2815A demo board has four user selectable operating modes:
- An accurate programmable EN/UVLO pin which is used to ENABLE the converter (JP1).
- Programmable MPPC (Maximum Power Point Control) for Input Regulation Set Point (JP2).
- Burst Mode® operation and External CLK/Fixed Frequency PWM (JP3).
- Programmable Output Average Current Limit Set Point (JP4).
The LT3120 uses average current mode control to simplify voltage loop compensation and provide good line and load transient response.
The DC2815A operates with a 2.5V to 26V input voltage range. The demo board has been designed with the output voltage set to 5V. The LT3120 incorporates a proprietary low noise switching algorithm which optimizes efficiency with input voltages above, below or equal to the output voltage and ensures seamless transitions between operating modes.
In PWM mode, the switching frequency can operate between 400kHz to 2MHz by programming the RT resistor R5. LT3120 can be synchronized to an External CLK provided RT is programmed 25% to 50% below the synchronization frequency.
The LT3120 has an optional programmable current limit that can be used to control the output current. The current limit circuit requires an external sense resistor connected between ISP and ISN and the current limit value can be set by adjusting R6 and C26 connected to PROG pin.
LT3120 also has programmable MPPC feature to set the input regulation voltage and can be adjusted by changing R13, R14 and C28.
The LT3120 data sheet has detailed information about the operation, specifications, and applications of the part. The data sheet should be read in conjunction with the DC2815A quick start guide.
Tools & Simulations
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.
Models for the following parts are available in LTspice:
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.
Sample & Buy
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Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.