Features and Benefits
- Dual Output Boost for Dual Display Devices
- Drives Up to Six White LEDs and OLED/LCD Bias
- Internal Power Switches and Schottky Diodes
- Independent Dimming and Shutdown
- 200mV High Side Sense on LED Driver Allows "One-Wire Current Source"
- Wide Input Voltage Range: 2.5V to 12V
- Wide Output Voltage Range: Up to 32V
- 2.3MHz PWM Frequency for LED Driver
- PFM for OLED Driver is Non-Audible Over Entire Load Range
- Open LED Protection (27V Maximum on CAP1 Pin)
- OLED Output Disconnect
- Available in 12-Pin DFN Package
- 1mm Tall Solution Height
The LT3498 is a dual output boost converter featuring a 2.3MHz PWM LED Driver and PFM OLED Driver. It includes an internal power switch and Schottky diode for each driver. Both converters can be independently shut down and modulated. This highly integrated power solution is ideal for dual display electronic devices.
The 2.3MHz step-up converter is designed to drive up to six white LEDs in series from a Li-Ion cell. The device features a unique high side LED current sense that enables the part to function as a “one-wire” current source—one side of the LED string can be returned to ground anywhere. Traditional LED drivers use a grounded resistor to sense LED current, requiring a 2-wire connection to the LED string.
The PFM OLED driver is a low noise boost converter that features a novel control technique.* The converter controls power delivery by varying both the peak inductor current and switch off time. This technique results in low output voltage ripple, as well as, high efficiency over a wide load range. The off time of the switch is not allowed to exceed a fixed level, guaranteeing a switching frequency that stays above the audio band.
- Cellular Phones
- PDAs, Handheld Computers
- Digital Cameras
- MP3 Players
- GPS Receivers
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 1137 is a 20mA Six White LED Driver and OLED driver with Integrated Schottky featuring the LT3498. The LT3498 is a dual output boost converter featuring a 2.3MHz PWM LED driver and a PFM (Pulse Frequency Modulation) OLED driver. The demo board is designed to operate from 3V to 5V, ideal for Li Ion battery powered dual display applications, such as main and sub-displays for cell phones.
The demo board offers flexible LED dimming methods. Users can use DC dimming, filtered PWM dimming or direct PWM dimming. The parts functions as a “one-wire” current source from the LED string point of view. The circuit protection clamps LED driver output to 27V (typ) if an open circuit condition occurs. When CTRL2 is higher than 1.5V, the demo board OLED supply output voltage is 16V. It can deliver up to 24mA from a 3V source.
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.