MAX1512 Maxim Integrated Products, MAX1512 Datasheet - Page 10

• Manufacturer Part Number: MAX1512
• Description: EEPROM-Programmable TFT VCOM Calibrator
• Manufacturer: Maxim Integrated Products

To avoid unintentional VCOM adjustment, the MAX1512
is guaranteed to reject CTL pulses shorter than 20µs. In
addition, to avoid the possibility of a single false pulse
caused by power-up sequencing between V
CTL, the very first pulse is ignored.
EEPROM-Programmable TFT VCOM Calibrator
Figure 7. EEPROM Programming
Table 1. EEPROM Programming Specifications
10
CTL Programming Voltage
CTL Programming Ramp
EEPROM Program Time
V
Done Hold Time
V
DD
PP
CTL VOLTAGE
V
/ 2
PP
0
Fall Time
______________________________________________________________________________________
PARAMETER
T1
T2
T3
SYMBOL
V
T1
T2
T3
T4
PP
T4
DD
TIME
and
15.25
MIN
200
7.0
0.9
10
To program the EEPROM, apply the EEPROM program-
ming waveform through the CTL interface (Figure 7).
The control interface delivers programming power and
DAC adjustment commands on the same wire. This
1-wire approach minimizes the number of connections
from the programming circuit to the LCD panel.
To apply the EEPROM programming waveform, carefully
ramp CTL from midscale (V
voltage, V
is generated digitally, use at least 45 steps to achieve
the required 320mV ramp resolution. During the ramp
time, VCOM adjustment is disabled and the EEPROM
cells are biased in preparation for programming. After
reaching V
EFPROM program time, the EEPROM stores the DAC
setting. Next, drive CTL to ground in less than 1ms and
hold for at least 200µs. Finally, drive CTL to V
complete the write cycle. The EEPROM is factory set to
half scale. Follow the EEPROM Programming Spec-
ifications in Table 1 to guarantee reliable EEPROM pro-
gramming. Violating the specifications can damage the
EEPROM or affect data retention.
A complete evaluation kit is available to simplify evalua-
tion and production development.
PP
TYP
15.5
7.5
1.0
PP
, in 7.5ms as shown in Figure 7. If the ramp
, hold CTL at V
EEPROM Programming (CTL)
15.75
MAX
1000
DD
8.0
1.1
PP
/ 2) to the programming
for 1ms. During the
UNITS
ms
ms
DD
µs
µs
V
/ 2 to