LM8342

ACTIVE

Programmable TFT Vcom Calibrator with Non-Volatile Memory

Product details

Display type LCD unipolar IC integration VCOM Vin (min) (V) 4.5 Vin (max) (V) 18 Applications 13 to 21 inches, 21 inches and above, 7 inches or less, 7 to 13 inches Source driver voltage (min) (V) 4.5 Source driver voltage (max) (V) 18 Level shifter/scan driver (Ch) 0 Features Gamma buffer, I2C interface, VCOM or op amp Rating Catalog Operating temperature range (°C) -40 to 85
Display type LCD unipolar IC integration VCOM Vin (min) (V) 4.5 Vin (max) (V) 18 Applications 13 to 21 inches, 21 inches and above, 7 inches or less, 7 to 13 inches Source driver voltage (min) (V) 4.5 Source driver voltage (max) (V) 18 Level shifter/scan driver (Ch) 0 Features Gamma buffer, I2C interface, VCOM or op amp Rating Catalog Operating temperature range (°C) -40 to 85
WSON (DSC) 10 9 mm² 3 x 3
  • I2C Compatible Programmable DAC to Set the Output Current
  • Ensured Monotonic DAC
  • Non-Volatile Memory to Hold the Setting
  • EEPROM in System Programmable
  • No External Programming Voltage Required
  • Maximum Interface Bus Speed is 400 kHz
  • SON-10 Package

All trademarks are the property of their respective owners.

  • I2C Compatible Programmable DAC to Set the Output Current
  • Ensured Monotonic DAC
  • Non-Volatile Memory to Hold the Setting
  • EEPROM in System Programmable
  • No External Programming Voltage Required
  • Maximum Interface Bus Speed is 400 kHz
  • SON-10 Package

All trademarks are the property of their respective owners.

The LM8342 is an integrated combination of a non-volatile register (7 bits EEPROM) and a DAC controlled current source. Using the LM8342, the VCOM calibration procedure is simplified by elimination of the potentiometer adjustment task. This adjustment task is currently performed at the factory using a trimmer adjustment tool and visual inspection.

The VCOM adjustment can be done electronically in production, using the I2C compatible interface. The factory operator can physically view the screen head-on (frontal viewing) when performing this step, easing manufacturing especially for large TFT panels.

The VCOM level is typically at half AVDD (determined by R1 and R2) and is buffered by the actual VCOM driver. By controlling the level of IOUT, the VCOM level can be tuned. The current level at the output of the LM8342 is a fraction (1/128 to 128/128) of a maximum current which is set by RSET and an analog reference (AVDD). The actual fraction is determined by the 7-bit DAC. As a result, the output current of the LM8342 has a good temperature stability yielding a very stable VCOM adjustment. Controlling the DAC setting of the LM8342 is done via its I2C compatible interface. The actual DAC setting is stored in a volatile register. Using a “Write to EE” command the data can be stored permanently in the embedded EEPROM. At power on of the device, the EEPROM data is copied to the volatile register, setting the DAC. At any time, the data in the EEPROM can be changed again via the I2C compatible interface.

The LM8342 is an integrated combination of a non-volatile register (7 bits EEPROM) and a DAC controlled current source. Using the LM8342, the VCOM calibration procedure is simplified by elimination of the potentiometer adjustment task. This adjustment task is currently performed at the factory using a trimmer adjustment tool and visual inspection.

The VCOM adjustment can be done electronically in production, using the I2C compatible interface. The factory operator can physically view the screen head-on (frontal viewing) when performing this step, easing manufacturing especially for large TFT panels.

The VCOM level is typically at half AVDD (determined by R1 and R2) and is buffered by the actual VCOM driver. By controlling the level of IOUT, the VCOM level can be tuned. The current level at the output of the LM8342 is a fraction (1/128 to 128/128) of a maximum current which is set by RSET and an analog reference (AVDD). The actual fraction is determined by the 7-bit DAC. As a result, the output current of the LM8342 has a good temperature stability yielding a very stable VCOM adjustment. Controlling the DAC setting of the LM8342 is done via its I2C compatible interface. The actual DAC setting is stored in a volatile register. Using a “Write to EE” command the data can be stored permanently in the embedded EEPROM. At power on of the device, the EEPROM data is copied to the volatile register, setting the DAC. At any time, the data in the EEPROM can be changed again via the I2C compatible interface.

Download View video with transcript Video

Technical documentation

star =Top documentation for this product selected by TI
No results found. Please clear your search and try again.
View all 2
Type Title Date
* Data sheet LM8342 Programmable TFT V COM Calibrator with Non-Volatile Memory datasheet (Rev. B) 25 Mar 2013
Application note How to Use the LM8342 VCOM Calibrator 06 Nov 2017

Design & development

For additional terms or required resources, click any title below to view the detail page where available.

Calculation tool

LM8342DESIGN-CALC LM8342 Component Calculation Spreadsheet

Supported products & hardware

Supported products & hardware

Products
LCD & OLED display power & drivers
LM8342 Programmable TFT Vcom Calibrator with Non-Volatile Memory
Simulation tool

PSPICE-FOR-TI — PSpice® for TI design and simulation tool

PSpice® for TI is a design and simulation environment that helps evaluate functionality of analog circuits. This full-featured, design and simulation suite uses an analog analysis engine from Cadence®. Available at no cost, PSpice for TI includes one of the largest model libraries in the (...)
Package Pins CAD symbols, footprints & 3D models
WSON (DSC) 10 Ultra Librarian

Ordering & quality

Information included:
  • RoHS
  • REACH
  • Device marking
  • Lead finish/Ball material
  • MSL rating/Peak reflow
  • MTBF/FIT estimates
  • Material content
  • Qualification summary
  • Ongoing reliability monitoring
Information included:
  • Fab location
  • Assembly location

Support & training

TI E2E™ forums with technical support from TI engineers

Content is provided "as is" by TI and community contributors and does not constitute TI specifications. See terms of use.

If you have questions about quality, packaging or ordering TI products, see TI support. ​​​​​​​​​​​​​​

Videos