Features and Benefits
- Wide Input Range:
- Operation from 4.1V to 60V
- Overvoltage Lockout Protects Circuit Through 80V Transients
- Two 1A Output Switching Regulators with Internal Power Switches
- Short Circuit Robust
- Adjustable 250kHz to 2.5MHz Switching Frequency, Synchronizable Over the Full Range
- Integrated Boost Diodes
- Integrated Loop Compensation
- Anti-Phase Switching Reduces Ripple
- Low Shutdown IQ (<2μA)
- Uses Small Inductors and Ceramic Capacitors
- Thermally Enhanced, 16-Lead MSOP Package
The LT3988 is a dual, current mode, step-down, DC/DC converter that accepts two input voltages up to 60V (80V transient), which may be driven from separate supplies or can be cascaded. High efficiency switches are included on the die along with internal boost diodes and loop compensation. Both converters are capable of generating 1A outputs, are synchronized to a single oscillator programmable up to 2.5MHz, and run with opposite phases, reducing input ripple current.
The switching frequency is set with a single resistor yielding a range of 250kHz to 2.5MHz, or a clock signal can be applied to the SYNC pin. The LT3988’s high switching frequency allows the use of small inductors and capacitors, resulting in a very small dual output supply. The constant switching frequency, combined with low impedance ceramic capacitors, results in low, predictable output ripple. A current mode PWM architecture provides fast transient response with cycle-by-cycle current limiting. Diode current sense and thermal shutdown provide additional protection.
The LT3988 is available in a 16-lead MSOP package with an exposed pad for low thermal resistance.
- Commercial Vehicle Battery Regulation
- Industrial Supplies
- Distributed Supply Regulation
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (1)
Demonstration circuit 1677A is a dual 60V monolithic 1A step-down regulator featuring the LT3988. The demo board operates from inputs up to 60V. The outputs are 5V, 1A and 3.3V, 1A. The wide input range of the LT3988 allows a variety of input sources, such as commercial vehicle batteries and industrial supplies. The switching frequency can be programmed either via oscillator resistor or external clock over a 250kHz to 2.5MHz range. The LT3988 internal boost diodes and loop compensation reduce the components count and solution size. The current mode control scheme creates fast transient response and good loop stability. The EN/UVLO pin can be used to set the part in micropower shutdown mode, reducing the supply current to less than 2μA.
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.
To launch ready-to-run LTspice demonstration circuits for this part:
Step 1: Download and install LTspice on your computer.
Step 2: Click on the link in the section below to download a demonstration circuit.
Step 3: If LTspice does not automatically open after clicking the link below, you can instead run the simulation by right clicking on the link and selecting “Save Target As.” After saving the file to your computer, start LTspice and open the demonstration circuit by selecting ‘Open’ from the ‘File’ menu.
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
The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.