MAX9665ETP+ Maxim Integrated, MAX9665ETP+ Datasheet - Page 12

• Manufacturer Part Number: MAX9665ETP+
• Description: LCD Gamma Buffers 6/8/10-Channel 10-Bit Nonvolatile Programmable Gamma and VCOM Reference Voltages
• Manufacturer: Maxim Integrated

6/8/10-Channel, 10-Bit, Nonvolatile Programmable
Gamma and VCOM Reference Voltages
MTP memory, which is a form of nonvolatile memory,
stores the DAC code values even when the chip is not
powered. When the chip is powered up, the code val-
ues are automatically transferred from MTP memory to
the I
Power-Up section for more details.
The user can program DAC codes into MTP memory for
up to 300 times. In conventional TFT-LCD applications, a
resistor string creates the gamma voltages. MTP memory
eliminates the resistor string and the need to change
manually the resistor values when searching for the opti-
mal gamma curve for a new TFT-LCD panel model.
The POR circuit that monitors DVDD ensures that all I
registers are reset to their MTP values upon power-up
or POR. Once DVDD rises above 2.4V (typ), the POR
circuit releases the I
in MTP are loaded. Should DVDD drop to less than 2.4V
typical, then the contents of the registers can no longer
be guaranteed and a reset is generated. When DVDD
rises back above the POR voltage, the values stored in
MTP are loaded back into the I
The transfer time of the MTP registers to I
300µs typical and is less than 400µs in the worst case.
During this time, AVDD should not be powered up, and
the I
only starts acknowledging commands after all registers
have been loaded from MTP).
When the die temperature reaches +165°C, all gamma
buffers except for the middle ones are disabled. See
Table 1.
When the die cools down by 15°C, all the buffers are
enabled again.
The VCOM operational amplifier does not have thermal
protection.
Table 1. Buffer Output Status During Thermal Shutdown
12
MAX9665
MAX9666
MAX9667
2
______________________________________________________________________________________
2
C does not acknowledge any commands (the I
PART
C registers. See the Power-On Reset (POR)/
Multiple-Time Programmable (MTP)
Power-On Reset (POR)/Power-Up
2
C registers and the values stored
OUT2 and OUT3
OUT3 and OUT4
OUT4 and OUT5
ENABLED
2
Thermal Protection
C registers.
2
C registers is
Memory
2
2
C
C
OUT0, OUT1, OUT2, OUT3, OUT6, OUT7, OUT8, OUT9
The MAX9665/MAX9666/MAX9667 have two digital
interfaces: I
face, the user can change all the registers and program
MTP memory. The I
pose of the two interfaces.
The single-wire interface, which is compatible with the
MAX1512 digital interface, is included to support TFT-
LCD production lines that depend upon the single-wire
interface to adjust the VCOM voltage to minimize flick-
er. Note that the single-wire interface cannot program
the gamma registers or gamma MTP memory.
To prevent any collision between the single-wire inter-
face and the I
face is only allowed if the other is in the idle state. For
example, if the I
ing a command, any input through the single-wire inter-
face is ignored. Conversely, if the single-wire interface
is in the middle of executing a command, the I
face does not acknowledge any commands.
Figure 2. VCOM Operational Amplifier with Feedback Resistors
OUT0, OUT1, OUT2, OUT5, OUT6, OUT7
Interoperability Between the Single-Wire
OUT0, OUT1, OUT4, OUT5
2
C and single-wire. Through the I
2
C interface, operation through one inter-
DISABLED
Interface and the I
2
C interface is in the middle of execut-
MAX9665
MAX9666
MAX9667
2
C interface is the more general pur-
Digital Interfaces
VCOM
FB
2
C Interface
2
2
C inter-
C inter-