Features and Benefits
- Flexible Power Supply System Capable of Four Regulated Outputs with VBATT << VOUT
- Two High Voltage Synchronous Buck Regulators
- 3V to 42V Input Voltage Range
- Output Currents Up to 2.5A and 1.5A
- One Low Voltage Synchronous Buck Regulator
- 2.6V to 5.5V Input Voltage Range
- Output Currents Up to 1.8A
- One Boost Controller Allows Buck Converters to Regulate with VBATT << VOUT
- Selectable Burst Mode® Operation Allows Low 28µA IQ with High Voltage Channels Active
- Programmable Power-On Reset
- Individual Channel Power Good Indicators
- Step-Down Switching Frequency: 250kHz to 2.2MHz
- Available in 40-Lead QFN (6mm × 6mm) Package
- AEC-Q100 Qualified for Automotive Applications
The LT8603 is a highly flexible, quad output regulator combining two high input voltage capable monolithic step-down switching regulators, one low input voltage capable monolithic step-down regulator, and a boost controller to satisfy a wide range of applications while occupying minimal board space.
With the boost controller configured to supply the chip VIN supply, the LT8603 produces three precisely regulated outputs even when the boost input voltage falls significantly below the regulated output voltages, such as during an automotive cold crank scenario. Alternatively, with the boost controller driven from one of the step-down regulator outputs or configured as a SEPIC, the LT8603 provides four precisely regulated outputs over a wide input voltage range.
The LT8603 provides robust regulation by including a cycle-by-cycle current limit for all step-down regulators, thermal shutdown, and a boost controller that can tolerate reverse battery connections and negative transient input voltages down to –42V.
- Automotive Stop-Start and Cold Crank Ride Through
- Last-Gasp CPU Power Hold-Up
- Industrial Controls and Power Supplies
Markets & Technology
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 (2)
Demonstration Circuit 2114A features the LT8603 with triple monolithic buck regulators and a boost controller. The demo circuit is designed for 8.0V, 5.0V, 3.3V, and 1.8V outputs from a nominal 12V input. The 4th channel is set as a boost converter and is powered from a wide input range with output VOUT4 regulated at 8V if 3V < VIN < 8.5V. It works as diode pass through if the input is above 8.5V. The two high voltage buck regulators are powered from the boost converter. VOUT1 is regulated at 5V with 1.5A maximum output load current, and VOUT2 is at 3.3V with 2.5A maximum output load current. Thanks to the pre-boost converter, they can ride through a cold crank in automotive applications while providing constant output voltages 5V and 3.3V. The low voltage buck is powered from the VOUT2 (3.3V), and the output VOUT3 is regulated at 1.8V with 1.8A maximum load current.
Demonstration circuit 2469A features the LT8603 with triple monolithic buck regulators and the boost channel as SEPIC. The demo circuit is designed for 8V, 5V, 3.3V, and 1.8V outputs from a nominal 12V input. The 4th channel is set as a SEPIC converter and its output is regulated at 8V over a wide input range. The two high voltage buck regulators are powered from VOUT4. VOUT1 is regulated at 5V with 1.5A maximum output load current, and VOUT2 is at 3.3V with 2.5A maximum output load current. The low voltage buck is powered from VOUT2 (3.3V), and the output VOUT3 is regulated at 1.8V with 1.8A maximum load current. Thanks to the SEPIC converter, all four outputs can ride through a cold crank in automotive applications while providing regulated output voltages.
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:
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Sample & Buy
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