Features and Benefits
- Wide Battery Input Range: 4.5V to 30V
- Grounded Lamp or Floating Lamp Configurations
- Open Lamp Protection
- Precision 50µA Full-Scale DAC Programming Current
- Standard SPI Mode or Pulse Mode
- DAC Setting Is Retained in Shutdown
The LT11186F is a fixed frequency, current mode, switching regulator that provides the control function for Cold Cathode Fluorescent Lighting (CCFL). The IC includes an efficient high current switch, an oscillator, output drive logic, control circuitry and a micropower 8-bit 50µA full-scale current output DAC. The DAC provides simple “bits-to-lamp current control” and communicates in two interface modes including standard SPI mode and pulse mode. On power-up, the DAC counter resets to half-scale and the DAC configures to SPI or pulse mode depending on the CS signal level. In SPI mode, the system microprocessor serially transfers the present 8-bit data and reads back the previous 8-bit data. In pulse mode, the upper six bits of the DAC configure as increment-only (1-wire interface) or increment/decrement (2-wire interface) operation depending on the DIN signal level.
The LT1186F control circuitry operates from a logic supply voltage of 3.3V or 5V. The IC also has a battery supply voltage pin that operates from 4.5V to 30V. The LT1186F draws 6mA typical quiescent current. An active low shutdown pin reduces total supply current to 35µA for standby operation and the DAC retains its last setting. A 200kHz switching frequency minimizes magnetic component size. Current mode switching techniques with cycle-by-cycle limiting gives high reliability and simple loop frequency compensation. The LT1186F is available in a 16-pin narrow SO package.
- Notebook and Palmtop Computers
- Portable Instruments
- Retail Terminals
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.
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.