Features and Benefits
- True Color PWM™ Dimming Delivers Up to 3000:1 Dimming Ratio
- Drives Six Strings of LEDs at Up to 30mA
- ±1.5% Accurate LED Current Matching
- Wide Input Voltage Range: 3.2V to 30V
- Output Voltage Up to 44V
- Regulates Current Even When VIN > VOUT
- Disconnects LEDs in Shutdown
- Programmable Open LED Protection (Regulated)
- OPENLED Alert Pin
- Programmable LED Current Derating
- Adjustable Frequency: 200kHz to 2.5MHz
- Synchronizable to an External Clock
- Parallel Channels for Higher Current per LED String
- Thermally Enhanced 4mm × 4mm QFN and 24-Lead TSSOP Packages
The LT3598 is a fixed frequency step-up DC/DC converter designed to drive up to six strings of LEDs at an output voltage up to 44V. LED dimming can be achieved with analog dimming on the CTRL pin, and with pulse width modulation dimming on the PWM pin. The LT3598 accurately regulates LED current even when the input voltage is higher than the LED output voltage. The switching frequency is programmable from 200kHz to 2.5MHz through an external resistor.
Additional features include programmable overvoltage protection, switching frequency synchronization to an external clock, LED current derating based on junction temperature and/or LED temperature, LED string disable control, OPENLED alert pin and output voltage limiting when all LED strings are disconnected. The LT3598 is available in a thermally enhanced 24-lead (4mm × 4mm) QFN and 24-lead TSSOP packages.
- Notebook Computer Display
- Medium Size Displays
- Automotive LCD Display
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 1285 is a 6-String 30mA LED Driver with 1.5% Current Matching featuring the LT3598. The LT3598 is a step-up DC/DC converter designed to drive up to 6-strings of LEDs at an output voltage up to 44V. The LED strings are connected to internal current sources where the current level is set with an external resistor. The input demo board input voltage range is 3.2V to 5.5V, limited by the voltage rating of the bias capacitor, C2. The IC voltage rating is 30V.
The demonstration circuit is configured to drive 20mA through each LED string. Each string can have up to 10 white LEDs. The circuit operation frequency is set to 1MHz. Parameters such as the LED current; the switching frequency, etc can be modified easily based on the demo circuit.
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.